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Browse Health
Family Practitioner, Primary Care Doctor
7 years of experience
Accepting new patients

Credentials

Education ?

Medical School
(2005)

Affiliations ?

Dr. Burns is affiliated with 2 hospitals.

Hospital Affiliations

Score

Rankings

  • Lehigh Valley Hospital
    1200 S Cedar Crest Blvd, Allentown, PA 18103
    •  
    Top 25%
  • Lehigh Valley Hospital - Muhlenberg
    2545 Schoenersville Rd, Bethlehem, PA 18017
    •  
    Top 25%
  • Publications & Research

    Dr. Burns has contributed to 153 publications.
    Title Interaction of Prenatal Exposure to Cigarettes and Maoa Genotype in Pathways to Youth Antisocial Behavior.
    Date December 2010
    Journal Molecular Psychiatry
    Excerpt

    Genetic susceptibility to antisocial behavior may increase fetal sensitivity to prenatal exposure to cigarette smoke. Testing putative gene x exposure mechanisms requires precise measurement of exposure and outcomes. We tested whether a functional polymorphism in the gene encoding the enzyme monoamine oxidase A (MAOA) interacts with exposure to predict pathways to adolescent antisocial behavior. We assessed both clinical and information-processing outcomes. One hundred seventy-six adolescents and their mothers participated in a follow-up of a pregnancy cohort with well-characterized exposure. A sex-specific pattern of gene x exposure interaction was detected. Exposed boys with the low-activity MAOA 5' uVNTR (untranslated region variable number of tandem repeats) genotype were at increased risk for conduct disorder (CD) symptoms. In contrast, exposed girls with the high-activity MAOA uVNTR genotype were at increased risk for both CD symptoms and hostile attribution bias on a face-processing task. There was no evidence of a gene-environment correlation (rGE). Findings suggest that the MAOA uVNTR genotype, prenatal exposure to cigarettes and sex interact to predict antisocial behavior and related information-processing patterns. Future research to replicate and extend these findings should focus on elucidating how gene x exposure interactions may shape behavior through associated changes in brain function.

    Title Genetic Adaptation of Pseudomonas Aeruginosa to the Airways of Cystic Fibrosis Patients is Catalyzed by Hypermutation.
    Date December 2008
    Journal Journal of Bacteriology
    Excerpt

    In previous work (E. E. Smith, D. G. Buckley, Z. Wu, C. Saenphimmachack, L. R. Hoffman, D. A. D'Argenio, S. I. Miller, B. W. Ramsey, D. P. Speert, S. M. Moskowitz, J. L. Burns, R. Kaul, and M. V. Olson, Proc. Natl. Acad. Sci. USA 103:8487-8492, 2006) it was shown that Pseudomonas aeruginosa undergoes intense genetic adaptation during chronic respiratory infection (CRI) in cystic fibrosis (CF) patients. We used the same collection of isolates to explore the role of hypermutation in this process, since one of the hallmarks of CRI is the high prevalence of DNA mismatch repair (MMR) system-deficient mutator strains. The presence of mutations in 34 genes (many of them positively linked to adaptation in CF patients) in the study collection of 90 P. aeruginosa isolates obtained longitudinally from 29 CF patients was not homogeneous; on the contrary, mutations were significantly concentrated in the mutator lineages, which represented 17% of the isolates (87% MMR deficient). While sequential nonmutator lineages acquired a median of only 0.25 mutation per year of infection, mutator lineages accumulated more than 3 mutations per year. On the whole-genome scale, data for the first fully sequenced late CF isolate, which was also shown to be an MMR-deficient mutator, also support these findings. Moreover, for the first time the predicted amplification of mutator populations due to hitchhiking with adaptive mutations in the course of natural human infections is clearly documented. Interestingly, increased accumulation of mutations in mutator lineages was not a consequence of overrepresentation of mutations in genes involved in antimicrobial resistance, the only adaptive trait linked so far to hypermutation in CF patients, demonstrating that hypermutation also plays a major role in P. aeruginosa genome evolution and adaptation during CRI.

    Title Large-insert Genome Analysis Technology Detects Structural Variation in Pseudomonas Aeruginosa Clinical Strains from Cystic Fibrosis Patients.
    Date July 2008
    Journal Genomics
    Excerpt

    Large-insert genome analysis (LIGAN) is a broadly applicable, high-throughput technology designed to characterize genome-scale structural variation. Fosmid paired-end sequences and DNA fingerprints from a query genome are compared to a reference sequence using the Genomic Variation Analysis (GenVal) suite of software tools to pinpoint locations of insertions, deletions, and rearrangements. Fosmids spanning regions that contain new structural variants can then be sequenced. Clonal pairs of Pseudomonas aeruginosa isolates from four cystic fibrosis patients were used to validate the LIGAN technology. Approximately 1.5 Mb of inserted sequences were identified, including 743 kb containing 615 ORFs that are absent from published P. aeruginosa genomes. Six rearrangement breakpoints and 220 kb of deleted sequences were also identified. Our study expands the "genome universe" of P. aeruginosa and validates a technology that complements emerging, short-read sequencing methods that are better suited to characterizing single-nucleotide polymorphisms than structural variation.

    Title A Phase 2 Study of Aztreonam Lysine for Inhalation to Treat Patients with Cystic Fibrosis and Pseudomonas Aeruginosa Infection.
    Date April 2008
    Journal Pediatric Pulmonology
    Excerpt

    BACKGROUND: Aztreonam lysine for inhalation (AZLI) is being developed for treatment of CF patients with Pseudomonas aeruginosa airway infection. METHODS: This double-blind, randomized, placebo-controlled Phase 2 study evaluated the safety, tolerability and efficacy of 75 and 225 mg AZLI administered BID for 14 days using the eFlow Electronic Nebulizer (Pari Innovative Manufacturers, Inc., Midlothian, VA). Patients were 13 years and older with FEV1>or=40% predicted, chronic P. aeruginosa infection, and had used no anti-pseudomonal antibiotics for 56 days. RESULTS: Of 131 patients screened, 105 received AZLI or placebo. Mean age was 26 years and mean FEV1 percent predicted was 77% at baseline. There was a statistically significant reduction, compared to placebo, in P. aeruginosa CFU density in each AZLI group at Days 7 and 14 (P<0.001). The planned primary analysis, percent change in FEV1 at Day 14, demonstrated no statistically significant difference. Post hoc analysis demonstrated significant increase in FEV1 at Day 7 for the subset of patients with baseline FEV1<75% predicted in the 225 mg AZLI group. Bronchodilator use was associated with greater improvement in FEV1, as well as greater reduction in P. aeruginosa bacterial density and higher plasma aztreonam concentrations in the 225 mg AZLI group. Adverse events were similar between placebo and AZLI although there was a trend toward increased respiratory symptoms in the 225 mg AZLI group. CONCLUSION: These data support the further development of AZLI and provide information for the design of subsequent studies.

    Title Correlations of Dietary Patterns with Prostate Health.
    Date March 2008
    Journal Molecular Nutrition & Food Research
    Excerpt

    Both genetic and environmental influences may be involved in etiology of prostate health and prostate cancer. These include ethnic origin, family history, smoking, and diet. Adiposity and excess energy intake are potentially distinct risk factors and positive associations with prostate cancer risk for both were observed among case-control and cohort studies. Some epidemiological studies support an association between dietary fat, particularly saturated or animal fats, and prostate cancer risk. Of these, several suggest reduced risk with low-fat diets high in n-3 fatty acids and increased risk with high-fat diets rich in n-6 fatty acids. Others suggested association with higher meat intake, possibly due to heterocyclic amines and polycyclic aromatic hydrocarbons, produced during grilling or frying. Positive association of prostate cancer risk with dairy intake could involve alpha-methylacyl-CoA racemase activity (required for beta-oxidation of phytanic acid present in dairy products and red meat) or the suppression of vitamin D activity by calcium. Inverse associations were observed with dietary intake of plant foods. These include cereals, soy products, and fruit and vegetable sources of carotenoids. Numerous plant constituents may act synergistically in the prevention and inhibition of prostate disorders. These diet-risk associations may lead to future individualized diet recommendations based upon genetic polymorphisms.

    Title Shewanella Putrefaciens Produces an Fe(iii)-solubilizing Organic Ligand During Anaerobic Respiration on Insoluble Fe(iii) Oxides.
    Date January 2008
    Journal Journal of Inorganic Biochemistry
    Excerpt

    The mechanism of Fe(III) reduction was investigated using voltammetric techniques in anaerobic incubations of Shewanella putrefaciens strain 200 supplemented with Fe(III) citrate or a suite of Fe(III) oxides as terminal electron acceptor. Results indicate that organic complexes of Fe(III) are produced during the reduction of Fe(III) at rates that correlate with the reactivity of the Fe(III) phase and bacterial cell density. Anaerobic Fe(III) solubilization activity is detected with either Fe(III) oxides or Fe(III) citrate, suggesting that the organic ligand produced is strong enough to destabilize Fe(III) from soluble or solid Fe(III) substrates. Results also demonstrate that Fe(III) oxide dissolution is not controlled by the intrinsic chemical reactivity of the Fe(III) oxides. Instead, the chemical reaction between the endogenous organic ligand is only affected by the number of reactive surface sites available to S. putrefaciens. This report describes the first application of voltammetric techniques to demonstrate production of soluble organic-Fe(III) complexes by any Fe(III)-reducing microorganism and is the first report of a Fe(III)-solubilizing ligand generated by a metal-reducing member of the genus Shewanella.

    Title Unique Lipid a Modifications in Pseudomonas Aeruginosa Isolated from the Airways of Patients with Cystic Fibrosis.
    Date October 2007
    Journal The Journal of Infectious Diseases
    Excerpt

    Three structural features of lipid A (addition of palmitate [C16 fatty acid], addition of aminoarabinose [positively charged amino sugar residue], and retention of 3-hydroxydecanoate [3-OH C10 fatty acid]) were determined for Pseudomonas aeruginosa isolates from patients with cystic fibrosis (CF; n=86), from the environment (n=13), and from patients with other conditions (n=14). Among P. aeruginosa CF isolates, 100% had lipid A with palmitate, 24.6% with aminoarabinose, and 33.3% retained 3-hydroxydecanoate. None of the isolates from the environment or from patients with other conditions displayed these modifications. These results indicate that unique lipid A modifications occur in clinical P. aeruginosa CF isolates.

    Title Pilus-mediated Epithelial Cell Death in Response to Infection with Burkholderia Cenocepacia.
    Date October 2007
    Journal Microbes and Infection / Institut Pasteur
    Excerpt

    Burkholderia cenocepacia is an opportunistic pathogen that can cause serious infections in cystic fibrosis (CF) patients. The ET12 lineage appears particularly virulent in CF; however, its pathogenesis is poorly understood and may be associated with host response. To help characterize this response, the ability of B. cenocepacia to induce cytotoxicity and apoptosis in an epithelial cell model was examined. Upon infection with B. cenocepacia strain K56-2, A549 human lung epithelial cells underwent significant cell death; propidium iodine staining and DNA fragmentation assays suggested apoptosis. Initiation of cell death was independent of the type III secretion system, biofilm formation, and secreted bacterial cytotoxins. However, the frequency of cell death was lower in cells infected with a non-piliated mutant, K56-2 cblA::Tp. Furthermore, purified cbl pili were found to directly induce cytotoxicity in A549 cells and activate caspase-9, -8, -7, and -3, the major cysteine proteinases involved in apoptosis. It appears that B. cenocepacia cbl pili, which are a distinctive feature of the ET12 lineage, act as an initiator of cytotoxicity and apoptosis. Understanding the role of cbl pili in the pathogenesis of B. cenocepacia infections offers the potential for decreasing the virulence of these potentially life-threatening organisms in CF patients.

    Title Allometric Growth Ratios Are Independent of Igf2 Gene Dosage During Development.
    Date October 2007
    Journal Evolution & Development
    Excerpt

    In the mouse, allelic dosage of the paternally expressed gene coding for insulin-like growth factor II (Igf2), from null to bi-allelic, results in dose-dependent growth, an effect which appears to be fully established during a discrete period of embryogenesis that then persists throughout life. Here, we specifically quantify the influence of Igf2 allelic dosage on the proportionality of regional embryonic growth rather than overall growth. Remarkably, preservation of allometric growth ratios between head and body regions were observed throughout development, irrespective of the range of overall growth phenotype (60-130% of wild type). Evaluation of log-log plots suggests that each allele of Igf2 expressed corresponds to the equivalent of 2-4 days of relative growth. Igf2 is predominantly expressed in extra-embryonic mesoderm (E7.5-E8.25), 24 h before alterations in cell number are known to occur in embryos with disruption of the paternally expressed allele. We hypothesized that the preservation of proportionality may result from modification of extra-embryonic development and subsequent alteration of systemic nutritional supply. Morphological analyses of chorio-allantoic and placental development between E9 and E9.5 appeared Igf2 independent. This suggests either an intrinsic but systemic Igf2-dependent activity within the embryo or a more complex developmental mechanism accounts for the proportional phenotype. Allelic IGF2 expression is subject to stochastic variation in humans, with 10% of the population estimated to be functionally bi-allelic. Evaluation of allometric growth of normal and pathological human embryos, suggest intra-uterine growth phenotypes associated with altered IGF2 imprinting are also likely to be proportionate.

    Title Duration of Treatment Effect After Tobramycin Solution for Inhalation in Young Children with Cystic Fibrosis.
    Date October 2007
    Journal Pediatric Pulmonology
    Excerpt

    RATIONALE: Among young children with cystic fibrosis (CF), Pseudomonas aeruginosa (Pa) airway infection is associated with increased morbidity and mortality. Early intervention strategies include tobramycin solution for inhalation (TSI), which can eradicate lower airway Pa from cultures obtained at the end of 28 days of treatment in young children. METHODS: We conducted an open label, sequential cohort study of TSI in young children with CF to investigate duration of antimicrobial treatment effect. The primary outcome was lower airway Pa eradication per bronchoalveolar lavage (BAL) fluid culture. Sequential treatment cohorts varied by duration of treatment (28 or 56 days) and timing of follow-up BAL (at Days 56, 84, or 112). Subjects (N = 36) were treated with TSI, 300 mg twice daily, for 28 days or 56 days per cohort assignment. RESULTS: Among 31 evaluable subjects, culture based, lower airway Pa eradication was observed in the majority of subjects for up to 1-3 months following TSI treatment: 75% in Cohort 28/56 (days of treatment/day of follow-up BAL), 63% in Cohort 28/84, 82% in Cohort 56/112, and 75% in Cohort 28/112. Non-mucoid Pa at baseline and/or exotoxin A seronegativity were associated with higher rates of eradication. There was a less pronounced effect of TSI treatment on Pa eradication from oropharyngeal cultures in all cohorts. TSI treatment was associated with reduced neutrophilic airway inflammation and was not related to any serious adverse events. CONCLUSION: TSI monotherapy is safe and can eradicate lower airway Pa for up to 3 months after treatment in young children with CF.

    Title Noninvasive Body Contouring by Focused Ultrasound: Safety and Efficacy of the Contour I Device in a Multicenter, Controlled, Clinical Study.
    Date August 2007
    Journal Plastic and Reconstructive Surgery
    Excerpt

    BACKGROUND: The removal of unwanted body fat using a noninvasive technique is desirable to patients and physicians. The authors describe a controlled, multicenter, clinical trial assessing the safety and efficacy of a focused therapeutic ultrasound device for noninvasive body contouring. METHODS: Eligible healthy adult subjects were enrolled to the experimental group or the control group at five sites. The experimental group received one treatment with the Contour I device (UltraShape Ltd., Tel Aviv, Israel) in the abdomen, thighs, or flanks and were evaluated over a 12-week period. Efficacy outcomes were reduction of circumference and fat thickness. Circumference reduction was compared with the untreated group and with an untreated area (thigh) within the treated group. Safety monitoring included laboratory testing (including serum lipids), pulse oximetry, and liver ultrasound. RESULTS: One hundred sixty-four subjects participated in the study (137 subjects in the experimental group and 27 in the control, untreated group). A single Contour I treatment was safe and well tolerated and produced a mean reduction of approximately 2 cm in treatment area circumference and approximately 2.9 mm in skin fat thickness. The majority of the effect was achieved within 2 weeks and was sustained at 12 weeks. No clinically significant changes in the measured safety parameters were recorded. Seven adverse events were reported, all of which were anticipated, mild, and resolved within the study period. CONCLUSION: The Contour I device provides a safe and effective noninvasive technology for body contouring.

    Title Blastomyces Antigen Detection for Monitoring Progression of Blastomycosis in a Pregnant Adolescent.
    Date August 2007
    Journal Infectious Diseases in Obstetrics and Gynecology
    Excerpt

    Although disseminated blastomycosis is a rare complication in pregnancy, delay in diagnosis and treatment can be fatal. We investigate the use of the Blastomyces urine antigen in diagnosis following disease progression in the intrapartum, postpartum, and neonatal periods. We describe a case of disseminated blastomycosis in a pregnant adolescent and review the pertinent literature regarding treatment and monitoring blastomycosis in pregnancy and the neonatal periods. This is the first reported case in which the Blastomyces urine antigen is utilized as a method of following disease activity during pregnancy confirming absence of clinically evident disease in a neonate. Urine antigen detection for blastomycosis can be useful for following progression of disease in patients with disseminated blastomycosis in both the intrapartum and postpartum periods.

    Title Terminal Electron Acceptors Influence the Quantity and Chemical Composition of Capsular Exopolymers Produced by Anaerobically Growing Shewanella Spp.
    Date August 2007
    Journal Biomacromolecules
    Excerpt

    Bacterial exopolymers perform various roles, including acting as a carbon sink, a protective layer against desiccation or antimicrobial agents, or a structural matrix in biofilms. Despite such varied roles, little is known about the heterogeneity of bacterial exopolymer production under varying growth conditions. Here we describe experiments designed to characterize the quantity and quality of exopolymers produced by two commonly studied members of the widely distributed genus Shewanella. Electrokinetic, spectroscopic, and electron microscopic techniques were employed to demonstrate that cell surfaces of Shewanella oneidensis MR-1 (electrophoretic softness, lambda(-1), range from 0.4 to 2.6 nm) are associated with less extracellular polymeric material than surfaces of Shewanella putrefaciens 200R (lambda(-1) range from 1.6 to 3.0 nm). Both species exhibit similar responses to changes in electron acceptor with nitrate- and fumarate-grown cells producing relatively little exopolymer compared to trimethylamine N-oxide (TMAO)-grown cells. In S. oneidensis, the increase in exopolymers has no apparent effect upon cell-surface fixed charge density (-7.7 to -8.7 mM), but for S. putrefaciens a significant drop in fixed charge density is observed between fumarate/nitrate-grown cells (-43 mM) and TMAO-grown cells (-20.8 mM). For both species, exopolymers produced during growth on TMAO have significant amide functionality, increasing from approximately 20-25% of C-containing moieties in nitrate-grown cells to over 30% for TMAO-grown cells (determined from X-ray photoelectron spectroscopy). The increased exopolymer layer associated with TMAO-grown cells appears as a continuous, convoluted layer covering the entire cell surface when viewed by low-temperature, high-resolution scanning electron microscopy. Such significant changes in cell-surface architecture, dependent upon the electron acceptor used for growth, are likely to influence a variety of cell interactions, including aggregation and attachment to surfaces, and the binding of aqueous metal species.

    Title Clinical Response to Azithromycin in Cystic Fibrosis Correlates with in Vitro Effects on Pseudomonas Aeruginosa Phenotypes.
    Date July 2007
    Journal Pediatric Pulmonology
    Excerpt

    A 6-month clinical trial of azithromycin (AZM) in American cystic fibrosis (CF) patients with chronic Pseudomonas aeruginosa infection showed clinical improvement without significant reduction in bacterial density. Sub-inhibitory AZM has been hypothesized to affect P. aeruginosa virulence, partly contributing to the mechanism of action of AZM. To correlate bacterial phenotypes of P. aeruginosa isolates with clinical response to AZM in CF patients. Pre-treatment P. aeruginosa isolates from subjects randomized to AZM in the US trial were characterized for bacterial phenotypes: AZM minimal inhibitory concentration (MIC), mucoidy, and baseline and AZM effects on twitching and swimming motility, and production of pyocyanin, protease and phospholipase C (PLC). Initial analyses of a subset of subjects identified phenotypes most strongly associated with FEV(1) response and pulmonary exacerbation. These phenotypes were subsequently characterized and tested in isolates from subjects of the complete AZM cohort. Exploratory analyses of the initial subset suggested that the MIC and in vitro change in PLC and swimming motility with AZM were the strongest candidates among the bacterial phenotypes. When tested, only the change in PLC was significantly correlated with the change in FEV(1) (P=0.05), and occurrence and time to pulmonary exacerbation (both P=0.02). In the complete cohort, change in PLC continued to show significant correlation with FEV(1) response (P=0.006), but not exacerbation. The in vitro effect of AZM on PLC correlates with FEV(1) response to AZM. This suggests that AZM anti-virulence effects may be predictive of clinical response and play a role in the mechanism of action of AZM in CF patients.

    Title The Effect of Molecular Weight of Nonadsorbing Polymer on the Structure of Depletion-induced Flocs.
    Date June 2007
    Journal Journal of Colloid and Interface Science
    Excerpt

    This work explores the structural compactness of depletion-induced particle flocs with respect to the molecular weight of nonadsorbing polymer flocculants. Small-angle static light scattering was used to monitor the structural characteristics of the flocs, which were formed by the addition of nonadsorbing poly(acrylic acids) to a stable colloidal polystyrene latex dispersion. It was found that the floc mass fractal dimension, considered to be a measure of structural compactness, was dependent upon both the molecular weight and the concentration of the polyacid. In particular, reducing the molecular weight of the polymer at a fixed polyacid concentration resulted in higher mass fractal dimensions, despite the highly polydisperse nature of the polymer samples. This structural behavior was attributed to the lower particle sticking efficiencies upon collision. This reduced sticking ability is the result of the shallowing in the secondary potential energy well with decreasing polymer chain length, which was directly supported by atomic force microscopy data. Our results suggest that the formation of a shallower attraction well with a lower molecular weight nonadsorbing polymer is the result of the insufficiency of the increased osmotic pressure to counter-balance the short-ranged nature of the depletion interaction.

    Title Association Between Pulmonary Function and Sputum Biomarkers in Cystic Fibrosis.
    Date June 2007
    Journal American Journal of Respiratory and Critical Care Medicine
    Excerpt

    RATIONALE: Sputum biomarkers of infection and inflammation are noninvasive measures that enable quantification of the complex pathophysiology of cystic fibrosis (CF) lung disease. Validation of these biomarkers as correlates of disease severity is a key step for their application. OBJECTIVES: We constructed a large database from four multicenter studies to quantify the strength of association between expectorated sputum biomarkers and FEV(1.) METHODS: FEV(1) (range, 25-120% predicted) and quantitative data on expectorated sputum biomarkers including free neutrophil elastase, IL-8, neutrophils, Pseudomonas aeruginosa, and Staphylococcus aureus were obtained from 269 participants (ages, 9-54 years) from 33 centers. Cross-sectional and longitudinal statistical analyses were performed to estimate associations between the markers and FEV(1), including the use of multivariable analyses. RESULTS: Elastase was negatively correlated with FEV(1) (correlation [r] = -0.35; 95% confidence interval [CI]: -0.46, -0.22). On average, patients with CF who differed in their elastase measurements by 0.5 log differed in their FEV(1) values by -7.3% (95% CI: -9.7, -4.6). Neutrophil counts and IL-8 were also each negatively correlated. In a multivariable regression, elastase and neutrophil counts were able to explain the majority of variation in FEV(1). Elastase was further shown to have a significant longitudinal association with FEV(1), specifically a -2.9% decline in FEV(1) (95% CI: -5.0, -0.9) per 1-log increase in elastase. Although correlated with FEV(1), bacterial densities were unable to explain clinically meaningful differences in FEV(1) within and across patients. CONCLUSIONS: These data support the role of sputum biomarkers as correlates of disease severity in a diverse CF population.

    Title Growth Phenotypes of Pseudomonas Aeruginosa Lasr Mutants Adapted to the Airways of Cystic Fibrosis Patients.
    Date May 2007
    Journal Molecular Microbiology
    Excerpt

    The opportunistic pathogen Pseudomonas aeruginosa undergoes genetic change during chronic airway infection of cystic fibrosis (CF) patients. One common change is a mutation inactivating lasR, which encodes a transcriptional regulator that responds to a homoserine lactone signal to activate expression of acute virulence factors. Colonies of lasR mutants visibly accumulated the iridescent intercellular signal 4-hydroxy-2-heptylquinoline. Using this colony phenotype, we identified P. aeruginosa lasR mutants that emerged in the airway of a CF patient early during chronic infection, and during growth in the laboratory on a rich medium. The lasR loss-of-function mutations in these strains conferred a growth advantage with particular carbon and nitrogen sources, including amino acids, in part due to increased expression of the catabolic pathway regulator CbrB. This growth phenotype could contribute to selection of lasR mutants both on rich medium and within the CF airway, supporting a key role for bacterial metabolic adaptation during chronic infection. Inactivation of lasR also resulted in increased beta-lactamase activity that increased tolerance to ceftazidime, a widely used beta-lactam antibiotic. Loss of LasR function may represent a marker of an early stage in chronic infection of the CF airway with clinical implications for antibiotic resistance and disease progression.

    Title Exacerbations in Cystic Fibrosis. 1: Epidemiology and Pathogenesis.
    Date May 2007
    Journal Thorax
    Excerpt

    With the improving survival of patients with cystic fibrosis (CF), the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is an acute pulmonary exacerbation. Clinical and microbial epidemiology studies of CF pulmonary exacerbations continue to provide important insight into the course, prognosis and complications of the disease. This review provides a summary of the pathophysiology, clinical epidemiology and microbial epidemiology of a CF pulmonary exacerbation.

    Title Characterization of Small-colony-variant Stenotrophomonas Maltophilia Isolated from the Sputum Specimens of Five Patients with Cystic Fibrosis.
    Date March 2007
    Journal Journal of Clinical Microbiology
    Excerpt

    Cystic fibrosis (CF) patients are predisposed to chronic respiratory infection by nonfermentative gram-negative bacilli, including Stenotrophomonas maltophilia. S. maltophilia is highly resistant to most antibiotics, with the exception of sulfamethoxazole-trimethoprim (SXT). SXT-resistant S. maltophilia has been reported, but the mechanism of resistance is not well defined. Repeated findings of suspected small-colony-variant (SCV) S. maltophilia isolates from the sputa of five CF patients were confirmed by partial 16S rRNA gene sequencing. The SCV S. maltophilia isolates were the only S. maltophilia isolates in these cultures, and none were clonally related. DNA fingerprint analysis confirmed that once established, the SCV S. maltophilia strains persisted. Nutritional studies of SCV S. maltophilia have suggested auxotrophy in hemin, methionine, and thymidine associated with resistance to multiple antibiotics, including SXT. The phenotypic switch from wild-type to SCV S. maltophilia was reproducible in vitro by exposure to SXT, suggesting that prolonged exposure to antibiotics may select for both the SCV S. maltophilia phenotype and SXT resistance by interference with the dihydrofolate reductase pathway. Recovery of SCV S. maltophilia from the sputum of CF patients has implications for both laboratory testing and patient management.

    Title Anti-inflammatory Properties of Macrolides.
    Date March 2007
    Journal The Pediatric Infectious Disease Journal
    Title Covariates of Tooth-brushing Frequency in Low-income African Americans from Grades 5 to 8.
    Date February 2007
    Journal Pediatric Dentistry
    Excerpt

    PURPOSE: The purpose of this study was to examine tooth-brushing frequency in 575 urban and nearby suburban African American children as part of a comprehensive risk-reduction study for students at high risk for violence, drugs, school delinquency, and unsafe sexual behaviors to determine which covariates predicted tooth-brushing frequency. METHODS: Students were surveyed 5 times, from the beginning of grade 5 and the end of each year through grade 8, and parents were surveyed at the beginning of grade 5. Peer influence, importance of being liked, self-esteem, attitudes towards tooth-brushing, oral health knowledge, self-efficacy, parental attitudes, and other covariates were examined for the ability to predict self-reporting of tooth-brushing frequency. RESULTS: In the fifth grade, peer influence, the importance of being liked, and physical self-esteem were the significant predictors, and peer influence continued to predict tooth-brushing in the eighth grade. Oral health knowledge and parental influence were not significant. CONCLUSION: Peer influence is an important factor in tooth-brushing behavior in metropolitan African American preadolescent children.

    Title Microbiology, Safety, and Pharmacokinetics of Aztreonam Lysinate for Inhalation in Patients with Cystic Fibrosis.
    Date February 2007
    Journal Pediatric Pulmonology
    Excerpt

    BACKGROUND: Aztreonam lysinate for inhalation (AI) is a novel monobactam formulation being investigated for pulmonary Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF). METHODS: Pre-clinical studies investigated the pre- and post-nebulization activity of AI and its activity in the presence of CF sputum. A double-blind, placebo-controlled, dose-escalation trial determined pharmacokinetics and tolerability of AI in subjects with CF. Single daily escalating doses of AI 75, 150, or 225 mg, or placebo were self-administered using an eFlow Electronic Nebulizer. Sputum samples were collected up to 4 hr and blood samples up to 8 hr post-dose. RESULTS: AI activity against multiple CF isolates was retained after nebulization via eFlow, and activity was not inhibited by CF sputum. All 12 adult subjects and 11/12 adolescents tolerated all AI doses. One patient had an asymptomatic FEV1 decrease > 20% with the 150 mg dose. Median aztreonam sputum concentrations in adults 10 min after AI 75, 150, and 225 mg were 383, 879, and 985 microg/g, respectively. Median sputum concentrations in adolescents 10 min after AI 75, 150, and 225 mg were 324, 387, and 260 microg/g, respectively. Systemic exposure to AI was low. Plasma pharmacokinetics in adults receiving AI 75 mg were Cmax = 419 ng/g, Tmax = 0.99 hr, t1/2 = 2.1 hr. Aztreonam concentrations in sputum were at or above the MIC50 for at least 4 hr post-dose. CONCLUSION: These data support the continued development of AI for treatment of pulmonary infections in patients with CF.

    Title Genetic Adaptation by Pseudomonas Aeruginosa to the Airways of Cystic Fibrosis Patients.
    Date July 2006
    Journal Proceedings of the National Academy of Sciences of the United States of America
    Excerpt

    In many human infections, hosts and pathogens coexist for years or decades. Important examples include HIV, herpes viruses, tuberculosis, leprosy, and malaria. With the exception of intensively studied viral infections such as HIV/AIDs, little is known about the extent to which the clonal expansion that occurs during long-term infection by pathogens involves important genetic adaptations. We report here a detailed, whole-genome analysis of one such infection, that of a cystic fibrosis (CF) patient by the opportunistic bacterial pathogen Pseudomonas aeruginosa. The bacteria underwent numerous genetic adaptations during 8 years of infection, as evidenced by a positive-selection signal across the genome and an overwhelming signal in specific genes, several of which are mutated during the course of most CF infections. Of particular interest is our finding that virulence factors that are required for the initiation of acute infections are often selected against during chronic infections. It is apparent that the genotypes of the P. aeruginosa strains present in advanced CF infections differ systematically from those of "wild-type" P. aeruginosa and that these differences may offer new opportunities for treatment of this chronic disease.

    Title Comparison of Biophysical and Biologic Properties of Alpha-helical Enantiomeric Antimicrobial Peptides.
    Date July 2006
    Journal Chemical Biology & Drug Design
    Excerpt

    In our previous study (Chen et al. J Biol Chem 2005, 280:12316-12329), we utilized an alpha-helical antimicrobial peptide V(681) as the framework to study the effects of peptide hydrophobicity, amphipathicity, and helicity on biologic activities where we obtained several V(681) analogs with dramatic improvement in peptide therapeutic indices against gram-negative and gram-positive bacteria. In the present study, the D-enantiomers of three peptides--V(681), V13A(D) and V13K(L) were synthesized to compare biophysical and biologic properties with their enantiomeric isomers. Each D-enantiomer was shown by circular dichroism spectroscopy to be a mirror image of the corresponding L-isomer in benign conditions and in the presence of 50% trifluoroethanol. L- and D-enantiomers exhibited equivalent antimicrobial activities against a diverse group of Pseudomonas aeruginosa clinical isolates, various gram-negative and gram-positive bacteria and a fungus. In addition, L- and D-enantiomeric peptides were equally active in their ability to lyse human red blood cells. The similar activity of L- and D-enantiomeric peptides on prokaryotic or eukaryotic cell membranes suggests that there are no chiral receptors and the cell membrane is the sole target for these peptides. Peptide D-V13K(D) showed significant improvements in the therapeutic indices compared with the parent peptide V(681) by 53-fold against P. aeruginosa strains, 80-fold against gram-negative bacteria, 69-fold against gram-positive bacteria, and 33-fold against Candida albicans. The excellent stability of D-enantiomers to trypsin digestion (no proteolysis by trypsin) compared with the rapid breakdown of the L-enantiomers highlights the advantage of the D-enantiomers and their potential as clinical therapeutics.

    Title Soluble Igf2 Receptor Rescues Apc(min/+) Intestinal Adenoma Progression Induced by Igf2 Loss of Imprinting.
    Date April 2006
    Journal Cancer Research
    Excerpt

    The potent growth-promoting activity of insulin-like growth factor-II (IGF-II) is highly regulated during development but frequently up-regulated in tumors. Increased expression of the normally monoallelic (paternally expressed) mouse (Igf2) and human (IGF2) genes modify progression of intestinal adenoma in the Apc(Min/+) mouse and correlate with a high relative risk of human colorectal cancer susceptibility, respectively. We examined the functional consequence of Igf2 allelic dosage (null, monoallelic, and biallelic) on intestinal adenoma development in the Apc(Min/+) by breeding with mice with either disruption of Igf2 paternal allele or H19 maternal allele and used these models to evaluate an IGF-II-specific therapeutic intervention. Increased allelic Igf2 expression led to elongation of intestinal crypts, increased adenoma growth independent of systemic growth, and increased adenoma nuclear beta-catenin staining. By introducing a transgene expressing a soluble form of the full-length IGF-II/mannose 6-phosphate receptor (sIGF2R) in the intestine, which acts as a specific inhibitor of IGF-II ligand bioavailability (ligand trap), we show rescue of the Igf2-dependent intestinal and adenoma phenotype. This evidence shows the functional potency of allelic dosage of an epigenetically regulated gene in cancer and supports the application of an IGF-II ligand-specific therapeutic intervention in colorectal cancer.

    Title Toothbrushing Patterns over Time in At-risk Metropolitan African-american 5th- 8th Graders.
    Date March 2006
    Journal Journal of Public Health Dentistry
    Excerpt

    OBJECTIVES: A large study of risky pre-teen behavior provided an opportunity to examine self-reported toothbrushing frequency for stability over time and adequacy. METHODS: 1115 metropolitan African-American children at risk for violence and drug use self-reported toothbrushing frequency in at least one of five measurement points from 5th to 8th grade as part of a larger study. Longitudinal data were available for 815 students. RESULTS: 81% reported mainly twice daily, 8% reported mainly once daily, 10% changed over time, and 1% were consistently less than once daily. CONCLUSIONS: Overall, the children reported once or twice daily toothbrushing frequency, stable between 5th and 8th grades. A minority of children showed low or inconsistent frequencies and these results may indicate an opportunity for intervention to improve habits.

    Title Anaerobic Killing of Mucoid Pseudomonas Aeruginosa by Acidified Nitrite Derivatives Under Cystic Fibrosis Airway Conditions.
    Date March 2006
    Journal The Journal of Clinical Investigation
    Excerpt

    Mucoid, mucA mutant Pseudomonas aeruginosa cause chronic lung infections in cystic fibrosis (CF) patients and are refractory to phagocytosis and antibiotics. Here we show that mucoid bacteria perish during anaerobic exposure to 15 mM nitrite (NO2) at pH 6.5, which mimics CF airway mucus. Killing required a pH lower than 7, implicating formation of nitrous acid (HNO2) and NO, that adds NO equivalents to cellular molecules. Eighty-seven percent of CF isolates possessed mucA mutations and were killed by HNO2 (3-log reduction in 4 days). Furthermore, antibiotic-resistant strains determined were also equally sensitive to HNO2. More importantly, HNO2 killed mucoid bacteria (a) in anaerobic biofilms; (b) in vitro in ultrasupernatants of airway secretions derived from explanted CF patient lungs; and (c) in mouse lungs in vivo in a pH-dependent fashion, with no organisms remaining after daily exposure to HNO2 for 16 days. HNO2 at these levels of acidity and NO2 also had no adverse effects on cultured human airway epithelia in vitro. In summary, selective killing by HNO2 may provide novel insights into the important clinical goal of eradicating mucoid P. aeruginosa from the CF airways.

    Title Use of Pseudomonas Biofilm Susceptibilities to Assign Simulated Antibiotic Regimens for Cystic Fibrosis Airway Infection.
    Date February 2006
    Journal The Journal of Antimicrobial Chemotherapy
    Excerpt

    OBJECTIVES: Increasing evidence indicates that Pseudomonas aeruginosa grows as a biofilm in the lungs of cystic fibrosis (CF) patients. In contrast, the bacterial inoculum used in conventional susceptibility testing is composed of planktonic cells. As a prelude to a clinical trial of biofilm susceptibility testing in CF, simulated antibiotic regimens based on either biofilm or conventional susceptibility testing of CF patient isolates were compared. PATIENTS AND METHODS: Biofilm and conventional susceptibilities were determined for P. aeruginosa isolate sets from 40 CF patients. An algorithm was used to assign simulated regimens of two anti-pseudomonal antibiotics for each patient/susceptibility method dataset. For agents with equivalent activity, the algorithm included a drug selection hierarchy, the rationale for which was suppression of chronic infection. Substitution of an alternative hierarchy, based on treatment of acute exacerbation, was used to evaluate the robustness of the regimen assignments. RESULTS: For both drug-ranking schemes, all 40 simulated regimens based on conventional susceptibilities included a beta-lactam antibiotic. In contrast, based on biofilm testing, only 43% of chronic regimens and 65% of acute regimens included a beta-lactam. Moreover, the conventional and biofilm regimens assigned to individual patients were discordant, with only 20% and 40% of chronic and acute regimens, respectively, consisting of drugs in the same two mechanistic classes by both methods. CONCLUSIONS: Biofilm susceptibility testing of CF P. aeruginosa isolate sets leads to different antibiotic assignments than conventional testing, with no single two-drug regimen predicted to provide optimal anti-biofilm activity against the majority of isolate sets.

    Title Conservation of a Novel Protein Associated with an Antibiotic Efflux Operon in Burkholderia Cenocepacia.
    Date September 2005
    Journal Fems Microbiology Letters
    Excerpt

    Burkholderia cenocepacia is a significant problem in individuals with cystic fibrosis and is a member of the B. cepacia complex of closely related antibiotic resistant bacteria. A salicylate-regulated antibiotic efflux operon has been identified in B. cenocepacia and one of its four genes, llpE, is without parallel in previously reported efflux operons. PCR amplification and sequencing of llpE from B. cepacia complex isolates demonstrated the highest prevalence in B. cenocepacia with a high degree of sequence conservation. While at least one non-synonymous mutation was identified between isolates from different genomovars, only synonymous differences were identified within the IIIA and IIIB sub-groups of B. cenocepacia. Structural modeling suggests that LlpE is a member of the alpha/beta hydrolase enzyme family. Identification of strong structural homology to hydrolases and a high degree of conservation in B. cenocepacia suggests an enzymatic function for LlpE, benefiting survival in the cystic fibrosis lung.

    Title Measuring Patient Acceptance of Implantable Cardiac Device Therapy: Initial Psychometric Investigation of the Florida Patient Acceptance Survey.
    Date July 2005
    Journal Journal of Cardiovascular Electrophysiology
    Excerpt

    INTRODUCTION: Patient acceptance of implantable device therapy has been established as an important outcome but the operationalization and validation of a measure of patient acceptance of implantable device therapy has not been fully completed. This study sought to validate a new measure of patient acceptance of cardiac implantable devices called the Florida Patient Acceptance Survey (FPAS). METHODS: The sample consisted of implantable cardioverter defibrillator (ICD; n = 58), and implantable atrioverter defibrillator (ICD-AT; n = 96), and pacemaker (PM, n = 84) patients. Mean age of all participants was 69 years; they were mostly male (62%) and married (75%). The final FPAS comprised 15 items with four consistent factors: Return to Function, Device-Related Distress, Positive Appraisal, and Body Image Concerns. RESULTS: The total FPAS demonstrated good internal consistency (Cronbach's alpha = 0.83), and internal consistency for each of the subscales ranged from 0.74 to 0.89. The FPAS demonstrated convergent, divergent, and discriminant validity when compared to other self-report measures of QOL, atrial symptoms, depression, and anxiety. A total FPAS score can be formed and between group comparisons with this sample indicated that ICD patients report a high level of acceptance (mean = 76), ICD-AT patients report a significantly higher level of acceptance (mean = 81.1), and PM patients reported the highest level of patient acceptance (mean = 85.4) of these implantable device groups. CONCLUSION: This initial psychometric investigation of the FPAS suggests that the FPAS may be useful in both clinical and research settings to assess patient acceptance of implantable cardiac devices.

    Title Hypermutable Haemophilus Influenzae with Mutations in Muts Are Found in Cystic Fibrosis Sputum.
    Date March 2005
    Journal Microbiology (reading, England)
    Excerpt

    Hypermutable bacterial pathogens exist at surprisingly high prevalence and benefit bacterial populations by promoting adaptation to selective environments, including resistance to antibiotics. Five hundred Haemophilus influenzae isolates were screened for an increased frequency of mutation to resistance to rifampicin, nalidixic acid and spectinomycin: of the 14 hypermutable isolates identified, 12 were isolated from cystic fibrosis (CF) sputum. Analysis by enterobacterial repetitive intergenic consensus (ERIC)-PCR and ribotyping identified eight distinct genetic fingerprints. The hypermutable phenotype of seven of the eight unique isolates was associated with polymorphisms in conserved sites of mutS. Four of the mutant mutS alleles were cloned and failed to complement the mutator phenotype of a mutS : : TSTE mutant of H. influenzae strain Rd KW20. Antibiotic susceptibility testing of the hypermutators identified one beta-lactamase-negative ampicillin-resistant (BLNAR) isolate with two isolates producing beta-lactamase. Six isolates from the same patient with CF, with the same genetic fingerprint, were clonal by multilocus sequence typing (MLST). In this clone, there was an evolution to higher MIC values for the antibiotics administered to the patient during the period in which the strains were isolated. Hypermutable H. influenzae with mutations in mutS are prevalent, particularly in the CF lung environment, and may be selected for and maintained by antibiotic pressure.

    Title Insulin-like Growth Factor Ligands, Receptors, and Binding Proteins in Cancer.
    Date March 2005
    Journal The Journal of Pathology
    Excerpt

    This review aims to summarize experimental evidence supporting the role of the insulin-like growth factor (IGF) signalling system in the progression, maintenance, and treatment of cancer. These data implicate the IGF system as an important modifier of cancer cell proliferation, survival, growth, and treatment sensitivity. The role of the IGF system in cancer should be examined in the context of the extra-cellular and intra-cellular signalling networks, in particular: phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt/PKB), mammalian target of rapamycin (mTOR), and forkhead transcription factors (FOXO). This review highlights evidence derived from molecular structure and functional genetics with respect to how the extra-cellular components of the IGF system function normally, and their subsequent modifications in cancer. The therapeutic relevance of the research evidence described is also addressed, as the challenge is to apply this knowledge to human health.

    Title Use of Phage Display to Identify Potential Pseudomonas Aeruginosa Gene Products Relevant to Early Cystic Fibrosis Airway Infections.
    Date January 2005
    Journal Infection and Immunity
    Excerpt

    Pseudomonas aeruginosa airway infections are a major cause of morbidity and mortality in patients with cystic fibrosis. Treatment of established infections is difficult, even with microbiologically active agents. Thus, prevention of infection is an important goal of management. Isolates from cystic fibrosis patients appear to originate from the environment but adapt to the milieu of the airway of the cystic fibrosis patient and evolve toward a common phenotype. Identification of the antigens expressed early in infection may lead to novel targets for vaccine development. Immunogenic peptides were identified in a J404 random nonapeptide phage display library with serum from cystic fibrosis patients obtained within the first year of P. aeruginosa infection. One hundred sixty-five reactive clones were verified by plaque lift assays, and their inserts were sequenced. The sequenced nonapeptides were compared with the published sequence of strain PAO1, identifying homologies to 76 genes encoding outer membrane and secreted proteins. The majority of these were proteins involved in small-molecule transport, membrane structural proteins, and secreted factors. An in silico analysis was performed that suggested that the occurrence of multiple matches to predominantly outer membrane and secreted proteins was not attributable to random chance. Finally, gene expression array data from early isolates of P. aeruginosa from cystic fibrosis patients was compared with the results from phage display analysis. Eleven outer membrane and secreted proteins were common between the two data sets. These included genes involved in iron acquisition, antibiotic efflux, fimbrial biogenesis, and pyocin synthesis. These results demonstrate the feasibility and validity of this novel approach and suggest potential targets for future development.

    Title Do Patients Accept Implantable Atrial Defibrillation Therapy? Results from the Patient Atrial Shock Survey of Acceptance and Tolerance (passat) Study.
    Date November 2004
    Journal Journal of Cardiovascular Electrophysiology
    Excerpt

    INTRODUCTION: The Medtronic Jewel AF 7250 is an implantable cardioverter defibrillator with atrial and ventricular therapies (ICD-AT). The ICD-AT is effective in managing atrial tachyarrhythmias (atrial fibrillation [AF]), but patient acceptance remains an issue. This aim of this study was to measure ICD-AT acceptance. METHODS AND RESULTS: ICD-AT acceptance was evaluated in 96 patients enrolled in the "Jewel AF-AF-Only Study" for > or =3 months of follow-up (mean 19 months). Patients were mostly men (72%; age 65 +/- 12 years). Clinical data and a written survey (75% response rate) were used to quantify demographics, AF frequency and symptoms, atrial defibrillation therapy, quality of life (QOL), psychosocial distress, and ICD-AT therapy acceptance. From implant to survey, AF symptom and severity scores decreased by 18% (P < or = 0.05), and QOL (SF-36) scores increased by 15% to 50% (P < or = 0.05). ICD-AT therapy acceptance was high, with 71.3% of patients scoring in the 75th percentile on the Florida Patient Acceptance Survey. ICD-AT acceptance was correlated with the Physical Component Scale and Mental Health Component Scale scores of the SF-36 (r = 0.28 and 0.35, respectively). ICD-AT acceptance was negatively correlated with depressive symptomatology (r =-0.59), trait anxiety (r =-0.48), illness intrusiveness (r =-0.55), and AF symptom and severity scores (r =-0.26). ICD-AT acceptance did not correlate with preimplant cardioversions, number of atrial shocks, AF episodes detected by the device, or device implant duration. CONCLUSION: Most patients accepted ICD-AT therapy. Patients were more likely to accept ICD-AT if they had less psychosocial distress, greater QOL, and lower AF symptom burden.

    Title Pandoraea Bacteremia in a Cystic Fibrosis Patient with Associated Systemic Illness.
    Date October 2004
    Journal The Pediatric Infectious Disease Journal
    Excerpt

    Pandoraea is a recently classified genus primarily isolated from the sputum of cystic fibrosis patients, but its pathogenic potential is unknown. We describe a case of Pandoraea bacteremia in a 16-year-old cystic fibrosis patient associated with clinical disease, suggesting that this organism should be considered a true pathogen in susceptible patients.

    Title Contribution of Burkholderia Cenocepacia Flagella to Infectivity and Inflammation.
    Date September 2004
    Journal Infection and Immunity
    Excerpt

    Burkholderia cenocepacia is an opportunistic pathogen that can cause severe lung infections in cystic fibrosis patients. To understand the contribution of B. cenocepacia flagella to infection, a strain mutated in the major flagellin subunit, fliCII, was constructed in B. cenocepacia K56-2 and tested in a murine agar bead model of lung infection. C57/BL6 mice infected with approximately 10(8) wild-type K56-2 bacteria exhibited 40% mortality after 3 days, whereas no mortality was noted in mice infected with the fliCII mutant. Among the mice surviving the infection with either strain, there was no significant difference in the bacterial loads in the lungs and spleen, bacteremia, weight loss, or infiltration of immune effector cells at 3 days postinfection. Similar results were observed at 24 h, prior to expression of the lethality phenotype. KC, a murine interleukin-8 (IL-8) homolog, was elevated in both the bronchoalveolar lavage fluid and serum of mice infected with the wild type compared to the fliCII mutant at 24 h, suggesting that flagella stimulated host cells. To demonstrate that flagella contributed to these responses, the interaction between B. cenocepacia and Toll-like receptor 5 (TLR5) was investigated. Infection of HEK293 cells with heat-killed wild-type K56-2, but not infection with the fliCII mutant, resulted in both NF-kappaB activation and IL-8 secretion that was dependent upon expression of TLR5. Together, these results demonstrate that B. cenocepacia flagella contribute to virulence in an in vivo infection model, and that induction of host immune responses through interaction with TLR5 may contribute to its overall pathogenic potential.

    Title Clinically Feasible Biofilm Susceptibility Assay for Isolates of Pseudomonas Aeruginosa from Patients with Cystic Fibrosis.
    Date September 2004
    Journal Journal of Clinical Microbiology
    Excerpt

    Pseudomonas aeruginosa is the predominant cause of chronic airway infection in cystic fibrosis (CF). CF airway isolates are often tested for antibiotic susceptibility but are rarely eradicated by the antibiotics identified as potentially effective. The growth state of P. aeruginosa in CF airways is probably different from that exhibited under conventional susceptibility testing conditions and may represent a bacterial biofilm. Biofilm susceptibility testing methods were adapted to create an assay for implementation in a clinical microbiology laboratory. This assay gave reproducible results when examined in 300 paired determinations with 12 antimicrobial agents, with a serious error rate of 5.7%. The biofilm assay was used retrospectively to test these 12 agents against 94 isolates from 41 CF patients. The biofilm inhibitory concentrations (BICs) were much higher than the corresponding conventionally determined MICs for the beta-lactam antibiotics (median values: aztreonam, >128 microg/ml versus 4 microg/ml; ceftazidime, 128 microg/ml versus 2 microg/ml; piperacillin-tazobactam, 256 microg/ml versus 4 microg/ml; and ticarcillin-clavulanate, 512 microg/ml versus 16 microg/ml, respectively) and doxycycline (>64 microg/ml versus 16 microg/ml); and similar for meropenem (4 micro g/ml versus < or = 1 microg/ml), ciprofloxacin (0.5 microg/ml versus 1 microg/ml), and the aminoglycosides amikacin (32 microg/ml versus 16 microg/ml), gentamicin (16 microg/ml versus 8 microg/ml), and tobramycin (4 microg/ml versus 2 microg/ml). The median BIC for azithromycin was 2 microg/ml, whereas isolates were uniformly resistant when tested by standard methods. This demonstrates the feasibility of adapting biofilm susceptibility methods to the clinical microbiology laboratory and opens the way to examining whether biofilm testing might be used to select more effective antibiotic combinations for CF airway infections than methods in current use.

    Title Effects of 2 Prevention Programs on High-risk Behaviors Among African American Youth: a Randomized Trial.
    Date May 2004
    Journal Archives of Pediatrics & Adolescent Medicine
    Excerpt

    OBJECTIVE: To test the efficacy of 2 programs designed to reduce high-risk behaviors among inner-city African American youth. DESIGN: Cluster randomized trial. SETTING: Twelve metropolitan Chicago, Ill, schools and the communities they serve, 1994 through 1998. PARTICIPANTS: Students in grades 5 through 8 and their parents and teachers. INTERVENTIONS: The social development curriculum (SDC) consisted of 16 to 21 lessons per year focusing on social competence skills necessary to manage situations in which high-risk behaviors occur. The school/community intervention (SCI) consisted of SDC and school-wide climate and parent and community components. The control group received an attention-placebo health enhancement curriculum (HEC) of equal intensity to the SDC focusing on nutrition, physical activity, and general health care. MAIN OUTCOME MEASURES: Student self-reports of violence, provocative behavior, school delinquency, substance use, and sexual behaviors (intercourse and condom use). RESULTS: For boys, the SDC and SCI significantly reduced the rate of increase in violent behavior (by 35% and 47% compared with HEC, respectively), provoking behavior (41% and 59%), school delinquency (31% and 66%), drug use (32% and 34%), and recent sexual intercourse (44% and 65%), and improved the rate of increase in condom use (95% and 165%). The SCI was significantly more effective than the SDC for a combined behavioral measure (79% improvement vs 51%). There were no significant effects for girls. CONCLUSIONS: Theoretically derived social-emotional programs that are culturally sensitive, developmentally appropriate, and offered in multiple grades can reduce multiple risk behaviors for inner-city African American boys in grades 5 through 8. The lack of effects for girls deserves further research.

    Title Sleep Quality Among Patients Treated with Implantable Atrial Defibrillation Therapy: Effect of Nocturnal Shock Delivery and Psychological Distress.
    Date March 2004
    Journal Journal of Cardiovascular Electrophysiology
    Excerpt

    INTRODUCTION: The Medtronic ICD-AT has atrial/ventricular therapies, which can be programmed to deliver atrial defibrillation during sleep, intended to potentially decrease shock anxiety/pain and lifestyle disruption. However, these shocks may diminish sleep quality. This study examined atrial shock characteristics (i.e., mode, frequency), AF symptoms, and psychological factors as determinants of sleep quality. METHODS AND RESULTS: The 96 ICD-AT patients were mostly men (72%; M age 65 +/- 12 years) and implanted for 1.6 years (SD = 0.8 years). Patients were divided into shock groups based on the proportion of mode (> or =90%) of total atrial shocks received. Patients were grouped into either automatic-nocturnal shock group (8 P.M.-8 A.M.; n = 35) or manual-awake shock group (n = 42). Psychological measures included Pittsburgh Sleep Quality Index (PSQI), Center for Epidemiology Studies-Depression Scale, State-Trait Anxiety Inventory, and Illness Intrusiveness Rating Scale. Atrial fibrillation disease burden was assessed via atrial symptom score and atrial shock use. PSQI global scores were similar between manual (7.67 +/- 2.53) and automatic shock (8.20 +/- 2.93) groups. A multiple hierarchical regression analysis indicated that no atrial shock variables were predictive of sleep quality; yet, both AF symptom (B = 0.226, P = 0.040) and depression (B = 0.392, P = 0.034) scores predicted diminished sleep quality, accounting for 42% of the variance in global sleep quality (P < 0.001). CONCLUSION: These results suggest that atrial defibrillation therapy does not have a deleterious impact on sleep. However, the significance of AF symptoms and depression indicate that comprehensive care of both physical and psychological symptomatology may improve sleep quality in ICD-AT patients.

    Title Salicylate Induces an Antibiotic Efflux Pump in Burkholderia Cepacia Complex Genomovar Iii (b. Cenocepacia).
    Date March 2004
    Journal The Journal of Clinical Investigation
    Excerpt

    An antibiotic efflux gene cluster that confers resistance to chloramphenicol, trimethoprim, and ciprofloxacin has been identified in Burkholderia cenocepacia (genomovar III), an important cystic fibrosis pathogen. Five open reading frames have been identified in the cluster. There is apparently a single transcriptional unit, with llpE encoding a lipase-like protein, ceoA encoding a putative periplasmic linker protein, ceoB encoding a putative cytoplasmic membrane protein, and opcM encoding a previously described outer membrane protein. A putative LysR-type transcriptional regulatory gene, ceoR, is divergently transcribed upstream of the structural gene cluster. Experiments using radiolabeled chloramphenicol and salicylate demonstrated active efflux of both compounds in the presence of the gene cluster. Salicylate is an important siderophore produced by B. cepacia complex isolates, and both extrinsic salicylate and iron starvation appear to upregulate ceoR promoter activity, as does chloramphenicol. These results suggest that salicylate is a natural substrate for the efflux pump in B. cenocepacia and imply that the environment of low iron concentration in the cystic fibrosis lung can induce efflux-mediated resistance, even in the absence of antibiotic selective pressure.

    Title Inflammatory and Microbiologic Markers in Induced Sputum After Intravenous Antibiotics in Cystic Fibrosis.
    Date February 2004
    Journal American Journal of Respiratory and Critical Care Medicine
    Excerpt

    Induced sputum has been used to study airway inflammation. We sought to determine whether markers of infection and inflammation in induced sputum were a useful and safe outcome measure in cystic fibrosis. We hypothesized that bacterial density and inflammatory content of induced sputum would decrease after antibiotic therapy. Induced sputum was assayed for bacterial density, cell count, and differential and inflammatory markers before and after treatment with intravenous antibiotics. Fifty-five of the 72 subjects enrolled (mean age +/- SD 18.2 +/- 7.9 years) completed the study. FEV1 increased by an average 0.3 +/- 0.3 L (10.4 +/- 8.7% predicted FEV1), p<0.0001; density of Pseudomonas aeruginosa and Staphylococcus aureus decreased by 2.4 +/- 3.1 log10 cfu/g (p<0.0005) and 4.0 +/- 2.3 log10 cfu/ml (p<0.0001), respectively; neutrophil count decreased by 0.4 +/- 0.6 log10 cells/ml (p<0.0001), interleukin-8 concentration by 0.5 +/- 1.3 log10 pg/ml (p<0.05), and neutrophil elastase by 0.4 +/- 0.7 log10 microg/ml (p<0.005). Seven of 127 (6%) sputum induction procedures showed a decrease in FEV1 of 20% or more. We conclude that markers in induced sputum may be useful, noninvasive outcome measures to assess response to therapies in cystic fibrosis studies.

    Title Genome Mosaicism is Conserved but Not Unique in Pseudomonas Aeruginosa Isolates from the Airways of Young Children with Cystic Fibrosis.
    Date February 2004
    Journal Environmental Microbiology
    Excerpt

    Pseudomonas aeruginosa strains from the chronic lung infections of cystic fibrosis (CF) patients are phenotypically and genotypically diverse. Using strain PAO1 whole genome DNA microarrays, we assessed the genomic variation in P. aeruginosa strains isolated from young children with CF (6 months to 8 years of age) as well as from the environment. Eighty-nine to 97% of the PAO1 open reading frames were detected in 20 strains by microarray analysis, while subsets of 38 gene islands were absent or divergent. No specific pattern of genome mosaicism defined strains associated with CF. Many mosaic regions were distinguished by their low G + C content; their inclusion of phage related or pyocin genes; or by their linkage to a vgr gene or a tRNA gene. Microarray and phenotypic analysis of sequential isolates from individual patients revealed two deletions of greater than 100 kbp formed during evolution in the lung. The gene loss in these sequential isolates raises the possibility that acquisition of pyomelanin production and loss of pyoverdin uptake each may be of adaptive significance. Further characterization of P. aeruginosa diversity within the airways of individual CF patients may reveal common adaptations, perhaps mediated by gene loss, that suggest new opportunities for therapy.

    Title Pathophysiology and Management of Pulmonary Infections in Cystic Fibrosis.
    Date November 2003
    Journal American Journal of Respiratory and Critical Care Medicine
    Excerpt

    This comprehensive State of the Art review summarizes the current published knowledge base regarding the pathophysiology and microbiology of pulmonary disease in cystic fibrosis (CF). The molecular basis of CF lung disease including the impact of defective cystic fibrosis transmembrane regulator (CFTR) protein function on airway physiology, mucociliary clearance, and establishment of Pseudomonas aeruginosa infection is described. An extensive review of the microbiology of CF lung disease with particular reference to infection with P. aeruginosa is provided. Other pathogens commonly associated with CF lung disease including Staphylococcal aureus, Burkholderia cepacia, Stenotrophomonas maltophilia, Achromobacter xylosoxidans and atypical mycobacteria are also described. Clinical presentation and assessment of CF lung disease including diagnostic microbiology and other measures of pulmonary health are reviewed. Current recommendations for management of CF lung disease are provided. An extensive review of antipseudomonal therapies in the settings of treatment for early P. aeruginosa infection, maintenance for patients with chronic P. aeruginosa infection, and treatment of exacerbation in pulmonary symptoms, as well as antibiotic therapies for other CF respiratory pathogens, are included. In addition, the article discusses infection control policies, therapies to optimize airway clearance and reduce inflammation, and potential future therapies.

    Title Use of Real-time Pcr with Multiple Targets to Identify Pseudomonas Aeruginosa and Other Nonfermenting Gram-negative Bacilli from Patients with Cystic Fibrosis.
    Date November 2003
    Journal Journal of Clinical Microbiology
    Excerpt

    Pseudomonas aeruginosa and other gram-negative isolates from patients with cystic fibrosis (CF) may be difficult to identify because of their marked phenotypic diversity. We examined 200 gram-negative clinical isolates from CF respiratory tract specimens and compared identification by biochemical testing and real-time PCR with multiple different target sequences using a standardized combination of biochemical testing and molecular identification, including 16S rRNA partial sequencing and gyrB PCR and sequencing as a "gold standard." Of 50 isolates easily identified phenotypically as P. aeruginosa, all were positive with PCR primers for gyrB or oprI, 98% were positive with exotoxin A primers, and 90% were positive with algD primers. Of 50 P. aeruginosa isolates that could be identified by basic biochemical testing, 100% were positive by real-time PCR with gyrB or oprI primers, 96% were positive with exotoxin A primers, and 92% were positive with algD primers. For isolates requiring more-extensive biochemical evaluation, 13 isolates were identified as P. aeruginosa; all 13 were positive with gyrB primers, 12 of 13 were positive with oprI primers, 11 of 13 were positive with exotoxin A primers, and 10 of 13 were positive with algD primers. A single false-positive P. aeruginosa result was seen with oprI primers. The best-performing commercial biochemical testing was in exact agreement with molecular identification only 60% of the time for this most difficult group. Real-time PCR had costs similar to those of commercial biochemical testing but a much shorter turnaround time. Given the diversity of these CF isolates, real-time PCR with a combination of two target sequences appears to be the optimum choice for identification of atypical P. aeruginosa and for non-P. aeruginosa gram-negative isolates.

    Title Azithromycin in Patients with Cystic Fibrosis Chronically Infected with Pseudomonas Aeruginosa: a Randomized Controlled Trial.
    Date October 2003
    Journal Jama : the Journal of the American Medical Association
    Excerpt

    CONTEXT: Treatment strategies for cystic fibrosis (CF) lung disease include antibiotics, mucolytics, and anti-inflammatory therapies. Increasing evidence suggests that macrolide antibiotics might be beneficial in patients with CF. OBJECTIVE: To determine if an association between azithromycin use and pulmonary function exists in patients with CF. DESIGN AND SETTING: A multicenter, randomized, double-blind, placebo-controlled trial conducted from December 15, 2000, to May 2, 2002, at 23 CF care centers in the United States. PARTICIPANTS: Of the 251 screened participants with a diagnosis of CF, 185 (74%) were randomized. Eligibility criteria included age 6 years or older, infection with Pseudomonas aeruginosa for 1 or more years, and a forced expiratory volume in 1 second (FEV1) of 30% or more. Participants were stratified by FEV1 (> or =60% predicted vs <60% predicted), weight of less than 40 kg vs 40 kg or more, and CF center. INTERVENTION: The active group (n = 87) received 250 mg (weight <40 kg) or 500 mg (weight > or =40 kg) of oral azithromycin 3 days a week for 168 days; placebo group (n = 98) received identically packaged tablets. MAIN OUTCOME MEASURES: Change in FEV1 from day 0 to completion of therapy at day 168 and determination of safety. Secondary outcomes included pulmonary exacerbations and weight gain. RESULTS: The azithromycin group had a mean 0.097-L (SD, 0.26) increase in FEV1 at day 168 compared with 0.003 L (SD, 0.23) in the placebo group (mean difference, 0.094 L; 95% confidence interval [CI], 0.023-0.165; P =.009). Nausea occurred in 17% more participants in the azithromycin group (P =.01), diarrhea in 15% more (P =.009), and wheezing in 13% more (P =.007). Participants in the azithromycin group had less risk of experiencing an exacerbation than participants in the placebo group (hazard ratio, 0.65; 95% CI, 0.44-0.95; P =.03) and weighed at the end of the study an average 0.7 kg more than participants receiving placebo (95% CI, 0.1-1.4 kg; P =.02). CONCLUSION: Azithromycin treatment was associated with improvement in clinically relevant end points and should be considered for patients with CF who are 6 years or older and chronically infected with P aeruginosa.

    Title Susceptibility Testing of Pseudomonas Aeruginosa Isolates and Clinical Response to Parenteral Antibiotic Administration: Lack of Association in Cystic Fibrosis.
    Date May 2003
    Journal Chest
    Excerpt

    STUDY OBJECTIVE: To determine the relationship between the antibiotic susceptibility of Pseudomonas aeruginosa isolated from the sputum of patients with cystic fibrosis (CF) and the patient's response to parenteral antibiotic administration, we performed a retrospective analysis using data from patients in the placebo arm of a phase 3 trial of tobramycin solution for inhalation. All patients were chronically infected with P aeruginosa. Seventy-seven of the 262 patients receiving placebo experienced a pulmonary exacerbation during the trial for which they received therapy with IV tobramycin and ceftazidime. The susceptibility of the P aeruginosa isolates to ceftazidime and tobramycin was determined at trial enrollment by broth microdilution. DESIGN: The clinical response to combination antibiotic therapy was assessed by analyzing differences in spirometry before and after antibiotic administration. The FEV(1) percent predicted at the first visit after the conclusion of antibiotic administration was compared to the FEV(1) percent predicted prior to antibiotic therapy. The results were analyzed both descriptively and by regression analyses. RESULTS: The conditions of 54 patients improved, and those of 9 patients worsened, and in 14 patients there was no change in FEV(1) with antibiotic administration. No correlation was observed between the susceptibility of P aeruginosa to tobramycin or ceftazidime and clinical response. Only the three following variables were observed to significantly correlate with FEV(1) after antibiotic treatment on regression analysis: FEV(1) prior to treatment (p < 0.0001); number of days elapsed between the previous FEV(1) measurement and the initiation of IV antibiotic therapy (p < 0.002); and the number of days elapsed between the determination of the minimum inhibitory concentration and the initiation of IV therapy (p < 0.03). No significant trends were observed between the antibiotic susceptibility of P aeruginosa isolates and treatment outcomes. CONCLUSION: While lack of statistical significance for a trend between bacterial susceptibilities and the response to parenteral antibiotic administration does not mean that no such trend exists, the precision of the confidence intervals allows us to conclude that even if isolate antibiotic susceptibilities affect outcome, the impact would be small and not clinically relevant.

    Title Viscosity Effect on the Structural Compactness of Latex Flocs Formed Under Weak Depletion Attractions.
    Date May 2003
    Journal Journal of Colloid and Interface Science
    Excerpt

    Dilute aqueous dispersions of colloidal polystyrene latex spheres were flocculated by adding a nonadsorbing polymer sample, poly(acrylic acid). The structural compactness of the flocs thus formed was characterized in terms of their mass fractal dimension using the small-angle static light scattering technique. It was found that with low poly(acrylic acid) concentrations and thus weak depletion attraction forces, the dispersion medium viscosity had a marked effect on the floc structure. An increase in the viscosity led to formation of denser flocs. This was revealed in three sets of depletion flocculation experiments: (a) adjusting the background electrolyte concentration at a fixed level of poly(acrylic acid), (b) using water and 30% (w/w) glycerol as the respective solvents, and (c) inducing latex flocculation with two poly(acrylic acids) of different molecular weights at the respective critical polyacid concentrations. Direct force measurements were made with atomic force microscopy to isolate the influence of viscosity on floc structure from that of interparticle interaction energies. We conclude that the formation of denser flocs with increasing medium viscosity can be attributed to the reduced diffusivity of particles in the solution. The latter resulted in an enhanced rate of floc restructuring (through relaxation of attached particles) relative to floc growth.

    Title Evaluation of Microscan Autoscan for Identification of Pseudomonas Aeruginosa Isolates from Cystic Fibrosis Patients.
    Date May 2003
    Journal Journal of Clinical Microbiology
    Excerpt

    Accurate identification of gram-negative bacilli from cystic fibrosis (CF) patients is essential. Only 57% (108 of 189) of nonmucoid strains and 40% (24 of 60) of mucoid strains were definitively identified as Pseudomonas aeruginosa with MicroScan Autoscan. Most common misidentifications were Pseudomonas fluorescens-Pseudomonas putida (i.e., the strain was either P. fluorescens or P. putida, but the system did not make the distinction and yielded the result P. fluorescens/putida) and Alcaligenes spp. Extending the incubation to 48 h improved identification, but 15% of isolates remained misidentified. The MicroScan Autoscan system cannot be recommended for the identification of P. aeruginosa isolates from CF patients.

    Title Significant Microbiological Effect of Inhaled Tobramycin in Young Children with Cystic Fibrosis.
    Date April 2003
    Journal American Journal of Respiratory and Critical Care Medicine
    Excerpt

    We conducted a double-blind, placebo-controlled, multicenter, randomized trial to test the hypothesis that 300 mg of tobramycin solution for inhalation administered twice daily for 28 days would be safe and result in a profound decrease in Pseudomonas aeruginosa (Pa) density from the lower airway of young children with cystic fibrosis. Ninety-eight subjects were to be randomized; however, the trial was stopped early because of evidence of a significant microbiological treatment effect. Twenty-one children under age 6 years were randomized (8 active; 13 placebo) and underwent bronchoalveolar lavage at baseline and on Day 28. There was a significant difference between treatment groups in the reduction in Pa density; no Pa was detected on Day 28 in 8 of 8 active group patients compared with 1 of 13 placebo group patients. We observed no differences between treatment groups for clinical indices, markers of inflammation, or incidence of adverse events. No abnormalities in serum creatinine or audiometry and no episodes of significant bronchospasm were observed in association with active treatment. We conclude that 28 days of tobramycin solution for inhalation of 300 mg twice daily is safe and effective for significant reduction of lower airway Pa density in young children with cystic fibrosis.

    Title Analysis of Sequential Aliquots of Hypertonic Saline Solution-induced Sputum from Clinically Stable Patients with Cystic Fibrosis.
    Date April 2003
    Journal Chest
    Excerpt

    STUDY OBJECTIVES: Sputum induction (SI) is a noninvasive tool for sampling inflamed airways. The purpose of this study was to determine the optimal duration of collection in patients with cystic fibrosis (CF). The hypothesis was that the duration of SI collection would quantitatively and qualitatively alter the content of the induced sputum. METHODS: In 10 clinically stable patients with CF (mean +/- SD age, 28 +/- 7 years; mean FEV(1), 2.6 +/- 0.7 L), SI was performed with 3% hypertonic saline solution at five time points over 20 min. RESULTS: SI was well tolerated, with an average maximum fall in FEV(1) of 7 +/- 7%. The sample volumes, urea concentrations, interleukin-8 concentrations, total cell counts, and nonsquamous cell counts remained constant (p > 0.05). The percentage of neutrophils decreased from 89 +/- 5% to 86 +/- 4% (p = 0.03), and the percentage of alveolar macrophages increased 5 +/- 2% to 8 +/- 4% (p < 0.01). The mean quantitative microbiological counts of nonmucoid Pseudomonas aeruginosa and Staphylococcus aureus decreased over the 20-min time period each by half a log (p = 0.05 and p < 0.01, respectively). Surfactant protein-A concentration increased from 1.6 +/- 0.3 to 2.4 +/- 0.4 ng/mL (log(10); p < 0.001). CONCLUSIONS: We conclude that aliquots of induced sputum are similar in clinically stable patients with CF during 4-min intervals, although there is more alveolar sampling after 20 min. When induced-sputum samples are fractionated for research monitoring of inflammatory or microbiologic indexes, power calculations accounting for these variations over time are required.

    Title Impairments to Wound Healing.
    Date April 2003
    Journal Clinics in Plastic Surgery
    Excerpt

    Impaired wound healing is a complication faced by all physicians, regardless of their field of practice. Plastic surgeons are frequently called on to help treat patients who fail to heal properly. Therefore, plastic surgeons must be well versed in the intrinsic and extrinsic factors that can impair wound healing, such as nutrition, drugs, radiation, smoking, and hypoxia. Only by limiting detrimental factors can wound healing progress in a beneficial fashion.

    Title Attenuated Virulence of a Burkholderia Cepacia Type Iii Secretion Mutant in a Murine Model of Infection.
    Date March 2003
    Journal Infection and Immunity
    Excerpt

    Type III secretion systems are utilized by a number of gram-negative bacterial pathogens to deliver virulence-associated proteins into host cells. Using a PCR-based approach, we identified homologs of type III secretion genes in the gram-negative bacterium Burkholderia cepacia, an important pulmonary pathogen in immunocompromised patients and patients with cystic fibrosis. One of the genes, designated bscN, encodes a member of a family of ATP-binding proteins believed to generate energy driving virulence protein secretion. Genetic dissection of the regions flanking the bscN gene revealed a locus consisting of at least 10 open reading frames, predicted to encode products with significant homology to known type III secretion proteins in other bacteria. A defined null mutation was generated in the bscN gene, and the null strain and wild-type parent strain were examined by use of a murine model of B. cepacia infection. Quantitative bacteriological analysis of the lungs and spleens of infected C57BL/6 mice revealed that the bscN null strain was attenuated in virulence compared to the parent strain, with significantly lower bacterial recovery from the lungs and spleens at 3 days postinfection. Moreover, histopathological changes, including an inflammatory cell infiltrate, were more pronounced in the lungs of mice infected with the wild-type parent strain than in those of mice infected with the isogenic bscN mutant. These results implicate type III secretion as an important determinant in the pathogenesis of B. cepacia.

    Title Whole-genome Sequence Variation Among Multiple Isolates of Pseudomonas Aeruginosa.
    Date March 2003
    Journal Journal of Bacteriology
    Excerpt

    Whole-genome shotgun sequencing was used to study the sequence variation of three Pseudomonas aeruginosa isolates, two from clonal infections of cystic fibrosis patients and one from an aquatic environment, relative to the genomic sequence of reference strain PAO1. The majority of the PAO1 genome is represented in these strains; however, at least three prominent islands of PAO1-specific sequence are apparent. Conversely, approximately 10% of the sequencing reads derived from each isolate fail to align with the PAO1 backbone. While average sequence variation among all strains is roughly 0.5%, regions of pronounced differences were evident in whole-genome scans of nucleotide diversity. We analyzed two such divergent loci, the pyoverdine and O-antigen biosynthesis regions, by complete resequencing. A thorough analysis of isolates collected over time from one of the cystic fibrosis patients revealed independent mutations resulting in the loss of O-antigen synthesis alternating with a mucoid phenotype. Overall, we conclude that most of the PAO1 genome represents a core P. aeruginosa backbone sequence while the strains addressed in this study possess additional genetic material that accounts for at least 10% of their genomes. Approximately half of these additional sequences are novel.

    Title Ciprofloxacin and Amoxicillin As Continuation Treatment of Febrile Neutropenia in Pediatric Cancer Patients.
    Date January 2003
    Journal Medical and Pediatric Oncology
    Excerpt

    BACKGROUND: The empiric administration of anti-microbial therapy significantly reduces the morbidity and mortality associated with febrile neutropenic episodes in oncology patients. Outpatient empiric antibiotic therapy can be safely administered to a subset of febrile neutropenic patients at low risk for clinical complications. PROCEDURE: Pediatric cancer patients presenting with febrile neutropenia after non-myeloablative chemotherapy and who met institutional criteria for early hospital discharge following a minimum of 48-hr inpatient empiric intravenous ceftazidime were eligible for the study. The feasibility and efficacy of an outpatient continuation therapy of oral ciprofloxacin (CPR) 25-30 mg/kg/day divided BID and amoxicillin (AMX) 30-50 mg/kg/day divided TID was assessed. RESULTS: Thirty febrile neutropenic episodes in 26 patients were treated with outpatient oral CPR/AMX therapy. Oral CPR/AMX therapy was feasible in 28 (93%) and efficacious in 26 (87%) of treatment episodes. CPR/AMX was discontinued due to abdominal pain and diarrhea (n = 2), recurrent fever (n = 3), or gastrointestinal bleeding (n = 1). No patient developed new bacteremia or cardiopulmonary decompensation. Bone/joint pain or gastrointestinal symptoms occurred in 27% of treatment episodes. Duration of neutropenia, lower absolute neutrophil count (ANC) (< 100/mm(3)) at start of oral antibiotic therapy and active malignant disease were associated with failure of oral antibiotic therapy. CONCLUSIONS: It is feasible to administer oral CPR/AMX as continuation antibiotic therapy for a selected subgroup of febrile neutropenic episodes defined after initial hospitalization and empiric antibiotic therapy. Prospectively randomized trials will be required to analyze adequately the efficacy of an oral CPR/AMX outpatient antibiotic regimen for treatment of febrile neutropenia in pediatric oncology patients.

    Title Utility of Gram Staining for Evaluation of the Quality of Cystic Fibrosis Sputum Samples.
    Date October 2002
    Journal Journal of Clinical Microbiology
    Excerpt

    The microscopic examination of Gram-stained sputum specimens is very helpful in the evaluation of patients with community-acquired pneumonia and has also been recommended for use in cystic fibrosis (CF) patients. This study was undertaken to evaluate that recommendation. One hundred one sputum samples from CF patients were cultured for gram-negative bacilli and examined by Gram staining for both sputum adequacy (using the quality [Q] score) and bacterial morphology. Subjective evaluation of adequacy was also performed and categorized. Based on Q score evaluation, 41% of the samples would have been rejected despite a subjective appearance of purulence. Only three of these rejected samples were culture negative for gram-negative CF pathogens. Correlation between culture results and quantitative Gram stain examination was also poor. These data suggest that subjective evaluation combined with comprehensive bacteriology is superior to Gram staining in identifying pathogens in CF sputum.

    Title The Effects of Different Types of Music on Perceived and Physiological Measures of Stress.
    Date October 2002
    Journal Journal of Music Therapy
    Excerpt

    The effects of different types of music on perceived and physiological measures of stress were evaluated. Sixty undergraduate psychology students, 31 males and 29 females, rated their level of relaxation and completed the State-Trait Anxiety Inventory (STAI) after they were told that they would be taking a stressful, mental test. Participants were randomly assigned to listen to different types of music or silence while skin temperature, frontalis muscle activity, and heart rate were recorded. Participants rated their relaxation and anxiety levels after listening to music or silence and completed the Mental Rotations Task Test. MANOVA's resulted in significant differences between groups for trait anxiety, F(57, 3) = 3.058, p =.036, and postmusic phase heart rate, F(57, 3) = 3.522, p =.021. Significant differences were also found between groups on state anxiety when trait anxiety was used as a covariate, F(57, 3) = 3.95, p =.024. The results of the research suggest that music may have an effect on the cognitive component of the stress response.

    Title Homeopathic Physician with His Vials of Medications.
    Date September 2002
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Factors Affecting the Incidence of Stenotrophomonas Maltophilia Isolation in Cystic Fibrosis.
    Date August 2002
    Journal Chest
    Excerpt

    STUDY OBJECTIVES: To identify factors predisposing cystic fibrosis (CF) patients to Stenotrophomonas maltophilia infection and to determine whether coinfection with S maltophilia affects the clinical response to therapy with tobramycin solution for inhalation (TSI), 300 mg bid. DESIGN: Retrospective review of data collected from two identical, 6-month, randomized, placebo-controlled trials. SETTING: Sixty-nine CF centers in the United States. INTERVENTIONS: Active drug administration of 300 mg TSI. PATIENTS: Five hundred twenty CF patients with chronic Pseudomonas aeruginosa endobronchial infections. MEASUREMENTS AND RESULTS: A logistic regression analysis identified factors contributing to increased S maltophilia isolation frequency. In this multivariate analysis, the only significant predictors of S maltophilia isolation during the last month of the trial were the concomitant use of oral quinolones (primarily ciprofloxacin; p = 0.0015) and S maltophilia isolation prior to treatment (p < 0.0001). Treatment group, gender, age, use of systemic or inhaled steroids, use of oral sulfonamide, IV cephalosporins, or penicillin antibiotics, baseline FEV(1) percent predicted, and pretreatment Aspergillus isolation were not significant predictors of subsequent S maltophilia infection. In addition, S maltophilia-positive culture frequency was compared to the change in pulmonary function. Patients who either never had culture results positive for S maltophilia or who were positive at <25% of observations had greater clinical response to TSI at the final study visit compared to patients who were positive at > or = 25% of observations. CONCLUSIONS: TSI therapy did not result in a greater risk for isolation of S maltophilia than standard care alone. In contrast, oral quinolone antibiotic use during the trial was associated with a 2.7-fold increased risk of having a culture positive for S maltophilia (p = 0.0015). The use of TSI to suppress P aeruginosa resulted in improved lung function, regardless of S maltophilia culture frequency. However, improvement was not as great among patients who were persistently coinfected with S maltophilia.

    Title Response to Recombinant Hepatitis B Vaccine in Children and Adolescents with Chronic Renal Failure.
    Date August 2002
    Journal American Journal of Kidney Diseases : the Official Journal of the National Kidney Foundation
    Excerpt

    BACKGROUND: Diminished antibody responses to the dosage of hepatitis B (HB) vaccine indicated for healthy adults has led to a greater dosage recommendation (40 microg of HB surface antigen [HBsAg]) for adults with chronic renal failure (CRF), but an appropriate dosage for children with CRF has not been established. METHODS: Seventy-eight children and adolescents with CRF (22 patients, predialysis; 42 patients, chronic dialysis therapy; 14 renal transplant recipients) aged 1 to 19 years (mean, 10.1 years) were enrolled onto a study to test a three 20-microg dose course of the HB vaccine Recombivax HB (Merck & Co, Inc, West Point, PA). RESULTS: The vaccine was well tolerated; no patient had a serious adverse event attributable to vaccine, and no patient withdrew from the study because of an adverse event. Overall, 91% of 66 patients administered three doses had a protective titer of 10 mIU/mL or greater for antibody against HBsAg (anti-HBs) and a geometric mean titer (GMT) of 733 mIU/mL, with seroprotection rates and GMTs among predialysis, dialysis, and renal transplant patients of 100% (4,140 mIU/mL), 94% (419 mIU/mL), and 64% (152 mIU/mL), respectively. All (100%) predialysis patients had a 10-mIU/mL or greater anti-HBs titer after only two doses of vaccine compared with 64% of dialysis patients and 50% of transplant recipients. Eighty-eight percent of 57 fully vaccinated patients tested 12 months after the first dose retained a 10-mIU/mL or greater anti-HBs titer. CONCLUSION: A regimen of three 20-microg doses of Recombivax HB is suitably immunogenic for children with CRF not administered immunosuppressive medication. When possible, at least two, and preferably all three, doses of vaccine should be administered before progression to end-stage renal disease.

    Title Ribosomal Dna-directed Pcr for Identification of Achromobacter (alcaligenes) Xylosoxidans Recovered from Sputum Samples from Cystic Fibrosis Patients.
    Date July 2002
    Journal Journal of Clinical Microbiology
    Excerpt

    The opportunistic human pathogen Achromobacter (Alcaligenes) xylosoxidans has been recovered with increasing frequency from respiratory tract culture of persons with cystic fibrosis (CF). However, confusion of this species with other closely related respiratory pathogens has limited studies to better elucidate its epidemiology, natural history, and pathogenic role in CF. Misidentification of A. xylosoxidans as Burkholderia cepacia complex is especially problematic and presents a challenge to effective infection control in CF. To address the problem of accurate identification of A. xylosoxidans, we developed a PCR assay based on a 16S ribosomal DNA sequence. In an analysis of 149 isolates that included 47 A. xylosoxidans and several related glucose-nonfermenting species recovered from CF sputum, the sensitivity and specificity of this PCR assay were determined to be 100 and 97%, respectively. The availability of this assay will enhance identification of A. xylosoxidans, thereby facilitating study of the pathogenic role of this species and improving infection control efforts in CF.

    Title Young at Heart: Understanding the Unique Psychosocial Adjustment of Young Implantable Cardioverter Defibrillator Recipients.
    Date July 2002
    Journal Pacing and Clinical Electrophysiology : Pace
    Excerpt

    This article reviews the data related to psychosocial adjustment of young ICD recipients, postulates theories to explain potential adjustment difficulties to ICD therapy experienced by younger recipients, and suggests clinical management techniques for addressing the unique psychosocial concerns of young ICD recipients. Studies of young ICD recipients suggest that a wide range of psychosocial adjustment issues are prominent in the post-ICD implantation period and that the issues may be different from older ICD recipients. The disability-stress-coping model and the transactional-stress-coping model are postulated as explanations for the unique adjustment concerns of children and adolescents with ICDs. Social comparison theory is also applied to the concerns of young adults with ICDs such that they often lack same age peers to compare experiences with cardiac difficulties. Brief, clinic-based interventions by health care providers, like a screening and referral heuristic and an "ICD Buddy" system, are suggested to increase effective coping and decrease social isolation for young ICD recipients.

    Title Emergence of New Pathogens in Cf: the Devil We Know or the Devil We Don't Know?
    Date April 2002
    Journal The Journal of Pediatrics
    Title Correlation Between an in Vitro Invasion Assay and a Murine Model of Burkholderia Cepacia Lung Infection.
    Date March 2002
    Journal Infection and Immunity
    Excerpt

    Our understanding of the virulence of Burkholderia cepacia complex lung infections in cystic fibrosis patients is incomplete. There is a great deal of variability in the clinical course, from simple colonization to severe and often fatal necrotizing pneumonia, termed cepacia syndrome. Multiple subspecies (called genomovars) have been identified, and these genomovars may hold the key to understanding the variable pathogenicity. Thirty-one B. cepacia complex isolates belonging to five of the seven genomovars were examined by using a gentamicin protection assay of invasion with A549 cells. The level of epithelial cell invasion by B. cepacia in the A549 model was relatively low compared with the data obtained for other pathogens and was often variable from assay to assay. Thus, a statistical approach was used to determine invasiveness. When this model was used, one of four genomovar I strains (25%), three of eight genomovar II strains (37.5%), seven of nine genomovar III strains (77.8%), one of four genomovar IV strains (25%), and none of the four genomovar V strains examined were defined as invasive. All other strains were categorized as either noninvasive or indeterminate. Invasive, noninvasive, and indeterminate isolates belonging to genomovars II and III were subsequently tested for splenic invasion with the mouse agar bead model. Correlation between the models for six strains was demonstrated. Our results indicate that a statistical model used to determine invasiveness in an in vitro invasion assay can be used to predict in vivo invasiveness.

    Title Comparison of Two Culture Methods for Detection of Tobramycin-resistant Gram-negative Organisms in the Sputum of Patients with Cystic Fibrosis.
    Date February 2002
    Journal Journal of Clinical Microbiology
    Excerpt

    A culture method utilizing quantitative plating on antibiotic-containing media has been proposed as a technique for the detection of tobramycin-resistant organisms that is more sensitive than standard methods. Typical sputum culture methods quantitate the relative amounts of each distinct morphotype, followed by antibiotic susceptibility testing of a single colony of each morphotype. Sputum specimens from 240 cystic fibrosis patients were homogenized, serially diluted, and processed in parallel by the standard method (MacConkey agar and OF basal medium with agar, polymyxin, bacitracin, and lactose) and by plating on antibiotic-containing media (MacConkey agar with tobramycin added at 25 microg/ml [MAC-25] and 100 microg/ml [MAC-100]). MICs of tobramycin were determined for all Pseudomonas aeruginosa isolates by broth microdilution. Growth of P. aeruginosa on MAC-25 was considered to be equivalent to a tobramycin MIC of > or = 16 microg/ml, and growth on MAC-100 was considered to be equivalent to a tobramycin MIC of > or = 128 microg/ml. Analysis of method-specific detection rates showed that tobramycin-containing medium was more sensitive than the standard method for the detection of tobramycin-resistant P. aeruginosa, Stenotrophomonas maltophilia, and Achromobacter xylosoxidans but was less sensitive for the detection of Burkholderia cepacia than the standard method. When MICs for P. aeruginosa that grew on tobramycin-containing medium were tested by broth microdilution, the MICs for 28 of 121 strains (23%) growing on MAC-25 and 22 of 56 strains (39%) growing on MAC-100 were MICs < 16 and < 128 microg/ml, respectively. Addition of a tobramycin-containing MacConkey plate to the routine media for sputum culture may provide additional, clinically relevant microbiologic data.

    Title Ampicillin Use in Infant Fever: a Systematic Review.
    Date January 2002
    Journal Archives of Pediatrics & Adolescent Medicine
    Excerpt

    OBJECTIVES: To estimate the prevalence of perinatal Listeria monocytogenes and enterococcal infections in outpatient febrile infants and to evaluate the need to treat with ampicillin. DATA SOURCES: Online bibliographies were searched for articles related to serious bacterial infection and fever in infants. Reference lists from selected and review articles were also examined. STUDY SELECTION: Studies that reported rates and types of bacterial infection in febrile outpatients younger than 3 months were included. Those performed outside North America, lacking results by age, or those that evaluated selected patient populations were excluded. DATA EXTRACTION: Two authors independently reviewed the selected articles for inclusion and abstracted the data. DATA SYNTHESIS: Fourteen studies, evaluating 5247 febrile outpatients, were included. The prevalences of L monocytogenes and enterococcal infections were 7.3 (binomial exact 95% confidence interval [CI], 3.5-13.3), 1.9 (95% CI, 0.6-4.4), and 5.6 (95% CI, 0.7-2.1) per 1000 febrile infants in the first, second, and third months of life, respectively. To cover 1 infant with serious bacterial infection caused by L monocytogenes and enterococcal infections, the numbers of febrile infants who would need ampicillin were estimated as 138 (95% CI, 76-288) in the first month, 527 (95% CI, 226-1621) in the second month, and 178 (95% CI, 50-1469) in the third month. Enterococcal infections occurred in all ages studied; there were no Listeria infections after 30 days of age. CONCLUSION: The empirical use of ampicillin to cover febrile infants for L monocytogenes and enterococcal infections is most justifiable in the first month of life.

    Title Burkholderia Cepacia--a Transmissible Cystic Fibrosis Pathogen.
    Date December 2001
    Journal The Journal of Pediatrics
    Title Cleaning Home Nebulizers Used by Patients with Cystic Fibrosis: is Rinsing with Tap Water Enough?
    Date December 2001
    Journal The Journal of Hospital Infection
    Title Use of Random Amplified Polymorphic Dna Pcr to Examine Epidemiology of Stenotrophomonas Maltophilia and Achromobacter (alcaligenes) Xylosoxidans from Patients with Cystic Fibrosis.
    Date December 2001
    Journal Journal of Clinical Microbiology
    Excerpt

    Stenotrophomonas maltophilia and Achromobacter (Alcaligenes) xylosoxidans have been increasingly recognized as a cause of respiratory tract colonization in cystic fibrosis (CF). Although both organisms have been associated with progressive deterioration of pulmonary function, demonstration of causality is lacking. To examine the molecular epidemiology of S. maltophilia and A. xylosoxidans in CF, isolates from patients monitored for up to 2 years were fingerprinted using a PCR-based randomly amplified polymorphic DNA (RAPD-PCR) method. Sixty-one of 69 CF centers screened had 183 S. maltophilia culture-positive patients, and 46 centers had 92 A. xylosoxidans-positive patients. At least one isolate from each patient was genotyped, and patients with > or =10 positive cultures (12 S. maltophilia cultures, 15 A. xylosoxidans cultures) had serial isolates genotyped. In addition, centers with multiple culture-positive patients were examined for evidence of shared clones. There were no instances of shared genotypes among different CF centers. Some patients demonstrated isolates with a single genotype throughout the observation period, and others had intervening or sequential genotypes. At the six centers with multiple S. maltophilia culture-positive patients and the seven centers with multiple A. xylosoxidans-positive patients, there were three and five instances of shared genotypes, respectively. The majority of shared isolates were from pairs who were siblings or otherwise epidemiologically linked. These findings suggest RAPD-PCR typing can distinguish unique CF isolates of S. maltophilia and A. xylosoxidans, person-to-person transmission may occur, there are not a small number of clones infecting CF airways, and patients with long-term colonization may either have a persistent organism or may acquire additional organisms over time.

    Title Early Pulmonary Infection, Inflammation, and Clinical Outcomes in Infants with Cystic Fibrosis.
    Date December 2001
    Journal Pediatric Pulmonology
    Excerpt

    A thorough understanding of the early natural history of cystic fibrosis (CF) lung disease is critical for the development of effective interventions in the youngest patients. We assessed the evolution of pulmonary infection, inflammation, and clinical course among 40 infants over a 2-year period through annual bronchoalveolar lavage (BAL) for culture and measurements of pro- and anti-inflammatory cytokines, semiannual infant pulmonary function testing, and quarterly clinical evaluations. Both the prevalence of CF pathogens and their density in BAL fluid increased with age. Infants had neutrophilic lower airway inflammation and elevated IL-8 concentrations independent of whether CF pathogens were recovered. Total leukocyte and neutrophil densities and IL-8 concentrations increased with density of CF pathogens in BAL fluid, whether the isolated organism was P. aeruginosa or another pathogen. IL-10 concentrations were similar in CF subjects and non-CF historical controls. Infants generally had suboptimal growth (low weight and height percentiles) and obstructive lung disease (decreased expiratory flows and air trapping). Subjects from whom CF pathogens were isolated at > 10(5) cfu/mL had the worst air trapping and lowest Brasfield chest X-ray scores. Our findings provide a foundation for future studies of early intervention in CF lung disease, including antimicrobial and anti-inflammatory therapy.

    Title Cell Survival and Proliferation Are Modified by Insulin-like Growth Factor 2 Between Days 9 and 10 of Mouse Gestation.
    Date December 2001
    Journal Development (cambridge, England)
    Excerpt

    The size of mammalian species involves the interaction of multiple genetic modifiers that control the timing and extent of growth mechanisms. Disruption of the paternal allele of the imprinted embryonic gene coding for insulin-like growth factor 2 (IGF2, Igf2(+m/-p)), results in viable mice that are 60% the weight of wild-type littermates. Differences in weight are first detected at embryonic day (E) 11, and the growth deficit is maintained throughout life. We report the mechanisms that account for this unusual phenotype. In order to quantify growth, we used novel methods to generate single cell suspensions of post-implantation mouse embryos. We were then able to quantify cell number, cell proliferation and cell death between E8.5 and E11.5 using flow cytometry. Determination of total embryo cell number also allowed us to time litters by a method other than by plugging. Wild-type and Igf2(+m/-p) embryos accumulated similar total cell numbers up to E9.25, but cell number began to diverge by around E9.5, with significant differences by E11 (75% of wild type). A relative increase in pyknotic nuclei, sub-GI cytometry counts and caspase activity, all indicative of cell death, occurred in Igf2(+m/-p) embryos at E9.25, reverting to wild-type levels by E9.75. This was followed at E9.75 by a significant reduction in the proportion of cells in S phase, quantified by S-phase cytometry counts and BrdU labelling. No significant differences in cell size were detected. We conclude that the majority of the cell number differences between wild-type and Igf2(+m/-p) mice can be accounted for by modification of cell survival and proliferation during the period (E9 to E10) of post-implantation development.

    Title Serum and Lower Respiratory Tract Drug Concentrations After Tobramycin Inhalation in Young Children with Cystic Fibrosis.
    Date December 2001
    Journal The Journal of Pediatrics
    Excerpt

    OBJECTIVES: To assess the serum and lower respiratory tract tobramycin concentrations (C(T)) produced by a single dose of tobramycin for inhalation delivered by a nebulizer and a compressor in patients with cystic fibrosis (CF) 6 months to 6 years of age. STUDY DESIGN: We performed a dose escalation study of serum C(T) measured before and 0.5, 1, 2, and 4 hours after a single dose of inhaled tobramycin, either 180 mg (10 patients) or 300 mg (19 patients). In a separate group of 12 patients, epithelial lining fluid (ELF) C(T) was measured by bronchoalveolar lavage 30 to 45 minutes after a 300-mg dose. RESULTS: A 180-mg dose of inhaled tobramycin produced a mean peak serum C(T) of 0.5 microg/mL (SD 0.4; range, <0.2 to 1.4 microg/mL). A 300-mg dose produced a mean peak serum C(T) of 0.6 microg/mL (SD 0.5; range, <0.2 to 1.2 microg/mL). These peak values are well below the accepted maximum trough concentration with parenteral dosing (2 microg/mL). The target ELF C(T) was 20 microg/mL, 10-fold greater than the minimal inhibitory concentration for most Pseudomonas aeruginosa isolates from very young patients with CF (2 microg/mL). Mean ELF C(T) was 90 microg/mL (SD 54; range, 16 to 204 microg/mL) and exceeded the target concentration in 11 patients. CONCLUSION: In patients with CF ages 6 months to 6 years, a single 300-mg dose of inhaled tobramycin appears to produce safe peak serum concentrations and drug concentrations in the bactericidal range in the lower respiratory tract.

    Title A View Through the Clouds of Imprinting.
    Date August 2001
    Journal The Faseb Journal : Official Publication of the Federation of American Societies for Experimental Biology
    Excerpt

    The purpose of this review is to examine whether our current knowledge of the higher order control of gene expression and nuclear organization can help us understand the mechanisms of genomic imprinting. Imprinting involves the inheritance of a silenced allele of a gene through either a paternal or maternal germline. We have approached the problem of imprinting using a model based on the dynamic attachment of chromatin loops to immobilized RNA polymerases and control elements. We have combined the information from different experimental approaches, examining primarily the IGF2-H19 locus, in an attempt to simplify the complexity of the imprinting data that has accumulated. It is hoped that a unified model may generate predictions amenable to experimental testing and contribute to the interpretation of future experiments.

    Title Comparison of Two Commercial Systems (vitek and Microscan-walkaway) for Antimicrobial Susceptibility Testing of Pseudomonas Aeruginosa Isolates from Cystic Fibrosis Patients.
    Date August 2001
    Journal Diagnostic Microbiology and Infectious Disease
    Excerpt

    Antimicrobial susceptibility testing of cystic fibrosis (CF) isolates of Pseudomonas aeruginosa is difficult because the organisms are often mucoid and slow-growing. This study of 498 CF strains examined the correlation of results derived from two commonly used commercial systems (Vitek, MicroScan-WalkAway) with a reference method for 10 antimicrobials. Correlation to reference results was unacceptably low for all agents and both commercial systems had a high rate of very major (false-susceptible) errors. Although mucoid strains produced a 4.8% greater intermethod error, it was not markedly different than non-mucoid strains for the Vitek System. Overall, these tested commercial systems performed poorly for CF isolates in contrast to earlier reported, high correlations with the reference methods (broth microdilution frozen panels and agar dilution) of the National Committee for Clinical Laboratory Standards, the standardized disk diffusion test, and the Etest (AB BIODISK, Solna, Sweden).

    Title Sputum Induction As a Research Tool for Sampling the Airways of Subjects with Cystic Fibrosis.
    Date April 2001
    Journal Thorax
    Excerpt

    BACKGROUND: Sputum induction (SI) has proved to be a reliable non-invasive tool for sampling inflammatory airway contents in asthma, with distinct advantages over collection of expectorated sputum (ES) and bronchoalveolar lavage (BAL). A study was undertaken to evaluate the safety of SI and to assess if it might be an equally valuable outcome tool in patients with cystic fibrosis (CF). METHODS: The safety of the procedure was examined and sample volume, cell counts, cytokine concentrations, and bacterial culture results obtained by SI, spontaneous ES, and fibreoptic bronchoscopy were compared in 10 adults with CF. RESULTS: SI was well tolerated and was preferred to BAL by all subjects. The mean (SE) sample volume obtained by SI was significantly greater than ES (6.74 (1.46) ml v 1.85 (0.33) ml, p = 0.005). There was no significant difference in the number of cells per ml of sample collected. There was a difference in the mean (SD) percentage of non-epithelial, non-squamous cells collected (67 (28)%, 86 (21)%, and 99 (1)% for ES, SI, and BAL, respectively). These percentage counts were different between ES and both SI and BAL (p=0.03 and p=0.006, respectively). Cell differential counts (excluding squamous cells) from all collection methods were similar (mean (SD) 84 (9)%, 87 (7)%, and 88 (11)% polymorphonuclear cells for ES, SI, and BAL, respectively). The concentrations of interleukin (IL)-8 and tumour necrosis factor (TNF)-alpha were the same in all three samples when corrected for dilution using urea concentration. The test specific detection rate for recovery of bacteriological pathogens was 79% for SI, 76% for ES, and 73% for BAL. CONCLUSION: SI offers safety advantages over BAL and may be a more representative airway outcome measurement in patients with CF.

    Title Longitudinal Assessment of Pseudomonas Aeruginosa in Young Children with Cystic Fibrosis.
    Date February 2001
    Journal The Journal of Infectious Diseases
    Excerpt

    Pseudomonas aeruginosa lung infection is an important cause of morbidity and mortality in cystic fibrosis (CF). Longitudinal assessment of the phenotypic changes in P. aeruginosa isolated from young children with CF is lacking. This study investigated genotypic and phenotypic changes in P. aeruginosa from oropharynx (OP) and bronchoalveolar lavage fluid (BALF) in a cohort of 40 CF patients during the first 3 years of life; antibody response was also examined. A high degree of genotypic variability was identified, and each patient had unique genotypes. Early isolates had a phenotype distinct from those of usual CF isolates: generally nonmucoid and antibiotic susceptible. Genotype and phenotype correlated between OP and BALF isolates. As determined by culture, 72.5% of patients demonstrated P. aeruginosa during their first 3 years. On the basis of combined culture and serologic results, 97.5% of patients had evidence of infection by age 3 years, which suggests that P. aeruginosa infection occurs early in CF and may be intermittent or undetectable by culture.

    Title Transcytosis of Gastrointestinal Epithelial Cells by Escherichia Coli K1.
    Date January 2001
    Journal Pediatric Research
    Excerpt

    Escherichia coli K1 is an important neonatal pathogen that is usually transferred from maternal to infant gastrointestinal tract at the time of parturition. Approximately 20% of neonates are colonized, and a proportion of colonized infants goes on to have systemic infection. Entry into the bloodstream from the gastrointestinal tract is hypothesized to occur via epithelial cell invasion. Invasion of multiple epithelial cell lines was studied using gentamicin protection assays and transcytosis of polarized monolayers. Electron microscopy was used to confirm cellular invasion. Cell lines used include two human gastrointestinal lines, Caco-2 and T84; a human respiratory cell line, A549; a human laryngeal cell line, HEp-2; and a canine kidney cell line, MDCK. A virulent E. coli K1 strain, RS218, readily invaded HEp-2, A549, and T84 cell lines in gentamicin protection assays, but was less invasive into MDCK and Caco-2 cells. RS218 also demonstrated transcytosis of both T84 and Caco-2 cells. Four clinical isolates of E. coli K1 demonstrated levels of transcytosis of T84 cells similar to RS218. Caco-2 invasiveness correlated with length of time in tissue culture with maximum invasiveness demonstrated at 11 d in culture, when cells were polarized and differentiated.

    Title Identification and Detection of Stenotrophomonas Maltophilia by Rrna-directed Pcr.
    Date January 2001
    Journal Journal of Clinical Microbiology
    Excerpt

    Stenotrophomonas maltophilia has recently emerged as an important nosocomial pathogen in immunocompromised patients, in transplant recipients, and in persons with cystic fibrosis (CF). While this organism is nonpathogenic in healthy individuals, it is increasingly associated with morbidity and mortality in susceptible populations. Recent studies have indicated that for approximately 10% of CF patients with moderate lung disease, S. maltophilia can be cultured from respiratory tract secretions. Identification of S. maltophilia can be problematic, and analysis of isolates from the Burkholderia cepacia Research Laboratory and Repository showed that several isolates presumptively identified as B. cepacia by clinical microbiology laboratories were in fact S. maltophilia. To overcome the problems associated with definitive identification, we developed species-specific PCR (SS-PCR) primers, designated SM1 and SM4, directed to the 23S rRNA gene, and tested their utility to accurately identify S. maltophilia directly from sputum. The SS-PCR was developed and tested against a panel of 112 S. maltophilia isolates collected from diverse geographic locations. To test for specificity, 43 isolates from 17 different species were analyzed. PCR with the SM1-SM4 primer pair and isolated genomic DNA as a template resulted in amplification of a band from all S. maltophilia isolates and was uniformly negative for all other species tested, yielding a sensitivity and a specificity of 100% for the SS-PCR. The utility of the SS-PCR to directly identify S. maltophilia in sputum was examined. Thirteen expectorated sputum samples from CF patients were analyzed by SS-PCR. Three samples were PCR positive, in complete concordance with the conventional laboratory culture. Thus, we have developed an SS-PCR protocol that can rapidly and accurately identify S. maltophilia isolates and which can be used for the direct detection of this organism in CF patient sputum.

    Title Massage Therapy.
    Date December 2000
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Infection Control in Cystic Fibrosis: Practical Recommendations for the Hospital, Clinic, and Social Settings.
    Date November 2000
    Journal American Journal of Infection Control
    Title Factor Analysis of the Condom Use Self-efficacy Scale Among Multicultural College Students.
    Date September 2000
    Journal Health Education Research
    Excerpt

    The Condom Use Self-Efficacy Scale (CUSES) was administered to 447 multicultural college students. The sample consisted of 63.5% Hispanic/Latino, 17.1% African-American, 13.7% Caucasian, 4.1% other and 1.6% Asian students. The obtained scores were subjected to a principal components factor analysis with a Varimax rotation. An item designation criteria was used and three distinct factors were extracted: (1) 'Appropriation', (2) 'Sexually Transmitted Diseases' and (3) 'Partners' Disapproval'. Comparisons to the only other published factor analysis of the CUSES are made. Implications for future research using the CUSES to design AIDS education curricula for multicultural college students are discussed.

    Title Comparison of Agar Diffusion Methodologies for Antimicrobial Susceptibility Testing of Pseudomonas Aeruginosa Isolates from Cystic Fibrosis Patients.
    Date June 2000
    Journal Journal of Clinical Microbiology
    Excerpt

    Pseudomonas aeruginosa is the most common pathogen infecting the lungs of patients with cystic fibrosis (CF). Improved antimicrobial chemotherapy has significantly increased the life expectancy of these patients. However, accurate susceptibility testing of P. aeruginosa isolates from CF sputum may be difficult because the organisms are often mucoid and slow growing. This study of 597 CF isolates of P. aeruginosa examined the correlation of disk diffusion and Etest (AB BIODISK, Solna, Sweden) results with a reference broth microdilution method. The rates of interpretive errors for 12 commonly used antipseudomonal antimicrobials were determined. The disk diffusion method correlated well (zone diameter versus MIC) for all of the agents tested. However, for mucoid isolates, correlation coefficients (r values) for piperacillin, piperacillin-tazobactam, and meropenem were <0.80. The Etest correlation with reference broth microdilution results (MIC versus MIC) was acceptable for all of the agents tested, for both mucoid and nonmucoid isolates. Category interpretation errors were similar for the disk diffusion and Etest methods with 0.4 and 0.1%, respectively, very major errors (false susceptibility) and 1.1 and 2.2% major errors (false resistance). Overall, both agar diffusion methods appear to be broadly acceptable for routine clinical use in susceptibility testing of CF isolates of P. aeruginosa.

    Title Aminoglycoside-resistance Mechanisms for Cystic Fibrosis Pseudomonas Aeruginosa Isolates Are Unchanged by Long-term, Intermittent, Inhaled Tobramycin Treatment.
    Date April 2000
    Journal The Journal of Infectious Diseases
    Excerpt

    Aminoglycoside-resistance mechanisms were characterized in Pseudomonas aeruginosa isolates from cystic fibrosis (CF) patients during a recent clinical trial of inhaled tobramycin. Impermeability, in which bacteria have reduced susceptibility to all aminoglycosides, was the predominant mode of resistance in isolates obtained both before and after 6 months of cyclic treatment with tobramycin or placebo administered by aerosol. Enzymatic resistance mechanisms were found in fewer than 10% of resistant isolates. P. aeruginosa from individual patients could be grouped on the basis of genetic relatedness. When enzymatic resistance was involved, all isolates in a group had elevated tobramycin MICs. When impermeability occurred, MICs of a genotypic group varied from susceptible to resistant. These findings suggest that impermeability resistance occurs in only a fraction of the P. aeruginosa population in lungs of persons with CF and that this form of resistance arises by a process involving multiple small changes in MIC.

    Title Activities of Tobramycin and Six Other Antibiotics Against Pseudomonas Aeruginosa Isolates from Patients with Cystic Fibrosis.
    Date January 2000
    Journal Antimicrobial Agents and Chemotherapy
    Excerpt

    The in vitro activity of tobramycin was compared with those of six other antimicrobial agents against 1,240 Pseudomonas aeruginosa isolates collected from 508 patients with cystic fibrosis during pretreatment visits as part of the phase III clinical trials of tobramycin solution for inhalation. The tobramycin MIC at which 50% of isolates are inhibited (MIC(50)) and MIC(90) were 1 and 8 microg/ml, respectively. Tobramycin was the most active drug tested and also showed good activity against isolates resistant to multiple antibiotics. The isolates were less frequently resistant to tobramycin (5.4%) than to ceftazidime (11.1%), aztreonam (11.9%), amikacin (13.1%), ticarcillin (16.7%), gentamicin (19.3%), or ciprofloxacin (20.7%). For all antibiotics tested, nonmucoid isolates were more resistant than mucoid isolates. Of 56 isolates for which the tobramycin MIC was > or = 16 microg/ml and that were investigated for resistance mechanisms, only 7 (12.5%) were shown to possess known aminoglycoside-modifying enzymes; the remaining were presumably resistant by an incompletely understood mechanism often referred to as "impermeability."

    Title Specific Lipopolysaccharide Found in Cystic Fibrosis Airway Pseudomonas Aeruginosa.
    Date December 1999
    Journal Science (new York, N.y.)
    Excerpt

    Cystic fibrosis (CF) patients develop chronic airway infections with Pseudomonas aeruginosa (PA). Pseudomonas aeruginosa synthesized lipopolysaccharide (LPS) with a variety of penta- and hexa-acylated lipid A structures under different environmental conditions. CF patient PA synthesized LPS with specific lipid A structures indicating unique recognition of the CF airway environment. CF-specific lipid A forms containing palmitate and aminoarabinose were associated with resistance to cationic antimicrobial peptides and increased inflammatory responses, indicating that they are likely to be involved in airway disease.

    Title Fifteen Years of Experience with Bacterial Meningitis.
    Date December 1999
    Journal The Pediatric Infectious Disease Journal
    Excerpt

    BACKGROUND: Introduction of Haemophilus influenzae type b (Hib) vaccines has dramatically altered the epidemiology of bacterial meningitis in children. The goal of this study was to describe these changes in a pediatric teaching hospital. METHODS: Patient charts at Children's Hospital and Regional Medical Center, Seattle, were identified by diagnosis codes and reviewed retrospectively. The 1981 to 1995 time period was chosen to incorporate three distinct 5-year periods: before the use of unconjugated Hib vaccine; between the unconjugated and conjugate vaccines; and after the conjugate vaccines were available for routine immunization of infants. RESULTS: Bacterial meningitis was identified in 806 cases. In 13 premature infant cases Escherichia coli was most frequently isolated (6 cases). Group B Streptococcus, E. coli and Listeria monocytogenes were the most common pathogens in 87 neonatal cases. The most common pathogens in 706 cases of childhood meningitis were H. influenzae, Streptococcus pneumoniae and Neisseria meningitidis. H. influenzae was the most common pathogen in the first two time periods (73 and 69% of childhood cases, respectively), but not so in the third period (16%). CONCLUSIONS: A changing pattern in childhood meningitis was observed during the study period. H. influenzae cases dramatically declined, altering the relative proportions of other pathogens, S. pneumoniae and N. meningitidis. However, the number of cases caused by these latter pathogens remained steady.

    Title Western Frontier Physician Taking Pulse.
    Date November 1999
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Chinese Folk Medicine: the Ceremony of Driving Away the Seventy-two Malignant Spirits.
    Date October 1999
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Evaluation of Reference Dilution Test Methods for Antimicrobial Susceptibility Testing of Pseudomonas Aeruginosa Strains Isolated from Patients with Cystic Fibrosis.
    Date September 1999
    Journal Journal of Clinical Microbiology
    Excerpt

    The development of multidrug-resistant Pseudomonas aeruginosa in patients with cystic fibrosis (CF) is most likely a consequence of increasing life expectancy and more prolonged exposure to antibiotics. The optimal method for antibiotic susceptibility testing of CF strains, particularly mucoid P. aeruginosa strains, is unknown. Antimicrobial susceptibilities of 48 CF strains (25 mucoid) and 50 non-CF strains to 12 anti-Pseudomonas agents were tested by both agar dilution and commercially custom-prepared broth microdilution plates (PML Microbiologicals, Portland, Oreg.) in three laboratories simultaneously to determine if broth microdilution could substitute for agar dilution as the reference method in subsequent studies. Comparison of MICs generated by agar dilution and broth microdilution demonstrated correlation coefficients (r) exceeding 0.85 for all agents tested; correlation was excellent for aminoglycosides (r >/= 0.92) and very good for beta-lactam agents including agents paired with a beta-lactamase inhibitor (r >/= 0.87) and for ciprofloxacin (r = 0.86). Correlation was not improved by 48-h readings, but correlation between 24- and 48-h readings ranged between 0.91 and 0.98 for both methods. Interlaboratory variations were minimal, as the percentage of acceptable variations was 94% for both methods, and serious discords were infrequent (<2% of comparisons). However, CF strains were more likely to have serious discords than were non-CF strains (P < 0. 0001), although mucoid strains were not more likely to have serious discords than were nonmucoid strains. In this study, MICs determined by custom-prepared broth microdilution compared favorably with MICs determined by agar dilution. Thus, this broth microdilution assay can serve as a reference method and facilitate future studies to determine the optimal method for antibiotic susceptibility testing of CF strains.

    Title Calcineurin is Required for Skeletal Muscle Hypertrophy.
    Date August 1999
    Journal The Journal of Biological Chemistry
    Excerpt

    Molecular signaling pathways linking increases in skeletal muscle usage to alterations in muscle size have not been identified. In the present study, we tested the hypothesis that calcineurin, a calcium-regulated phosphatase recently implicated in the signaling of some forms of cardiomyopathic growth, is required to induce skeletal muscle hypertrophy and muscle fiber type conversions associated with functional overload in vivo. Administration of the specific calcineurin inhibitors cyclosporin (CsA) or FK506 to mice, for which the fast plantaris muscle was overloaded for 1-4 weeks, prevented the rapid doubling of mass and individual fiber size and the 4-20-fold increase in the number of slow fibers that characterize this condition. CsA treatment influenced the expression of muscle myofibrillar protein genes in a way reflective of fiber phenotype transformations but only in the long term of the overload condition, suggesting that the control of this growth response by calcineurin is not limited to the transcriptional activation of these muscle-specific genes. Clinically, these results provide insight to the post-surgical muscle wasting and weakness observed in recovering transplant recipients administered therapeutic dosages of these immunosuppressants.

    Title Burkholderia Cepacia Infections in Cystic Fibrosis.
    Date July 1999
    Journal The Pediatric Infectious Disease Journal
    Title Effect of Chronic Intermittent Administration of Inhaled Tobramycin on Respiratory Microbial Flora in Patients with Cystic Fibrosis.
    Date June 1999
    Journal The Journal of Infectious Diseases
    Excerpt

    Pseudomonas aeruginosa endobronchial infection causes significant morbidity and mortality among cystic fibrosis patients. Microbiology results from two multicenter, double-blind, placebo-controlled trials of inhaled tobramycin in cystic fibrosis were monitored for longitudinal changes in sputum microbial flora, antibiotic susceptibility, and selection of P. aeruginosa isolates with decreased tobramycin susceptibility. Clinical response was examined to determine whether current susceptibility standards are applicable to aerosolized administration. Treatment with inhaled tobramycin did not increase isolation of Burkholderia cepacia, Stenotrophomonas maltophilia, or Alcaligenes xylosoxidans; however, isolation of Candida albicans and Aspergillus species did increase. Although P. aeruginosa tobramycin susceptibility decreased in the tobramycin group compared with that in the placebo group, there was no evidence of selection for the most resistant isolates to become most prevalent. The definition of resistance for parenteral administration does not apply to inhaled tobramycin: too few patients had P. aeruginosa with a tobramycin MIC >/=16 microgram/mL to define a new break point on the basis of clinical response.

    Title Nocardia Asteroides Septic Arthritis in a Healthy Child.
    Date May 1999
    Journal The Pediatric Infectious Disease Journal
    Title Comparison of Isolation Media for Recovery of Burkholderia Cepacia Complex from Respiratory Secretions of Patients with Cystic Fibrosis.
    Date April 1999
    Journal Journal of Clinical Microbiology
    Excerpt

    Burkholderia cepacia selective agar (BCSA) has previously been devised for isolation of B. cepacia from respiratory secretions of patients with cystic fibrosis and tested under research laboratory conditions. Here we describe a study in which BCSA, oxidation-fermentation polymyxin bacitracin lactose agar (OFPBL), and Pseudomonas cepacia agar (PCA) were compared in routine culture procedures for the ability to grow B. cepacia and inhibit other organisms. Three hundred twenty-eight specimens from 209 patients at two pediatric centers and 328 specimens from 109 adults were tested. Plates were inoculated, incubated, and read for quality and quantity of growth at 24, 48, and 72 h. Five (1.5%) specimens from 4 (1.9%) children and 75 (22.9%) specimens from 16 (14.7%) adults grew B. cepacia complex. At 24, 48, and 72 h, BCSA achieved 43, 93, and 100% detection, respectively; OFPBL achieved 26, 84, and 96%, respectively; and PCA achieved 33, 74, and 84% detection, respectively. Quality was assessed as pinpoint or good growth. At 24 h, most cultures growing B. cepacia complex had pinpoint colonies. By 48 and 72 h, 48 and 69% of B. cepacia complex cultures, respectively, had good growth on BCSA, while on OFPBL 19 and 30%, respectively, had good growth and on PCA 11 and 18%, respectively, had good growth. BCSA was superior to OFPBL and PCA in suppressing organisms other than B. cepacia complex; 40 non-B. cepacia complex organisms were isolated from BCSA, 263 were isolated from OFPBL, and 116 were isolated from PCA. We conclude that BCSA is superior to OFPBL and PCA in its ability to support the growth of B. cepacia complex and to suppress other respiratory organisms.

    Title A Lost Opportunity to Discover Antibiotics.
    Date December 1998
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Microbiology of Sputum from Patients at Cystic Fibrosis Centers in the United States.
    Date September 1998
    Journal Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America
    Excerpt

    During a phase III national collaborative study of aerosolized tobramycin (1 July 1995 through 30 September 1996), the microbiology of specimens from 595 patients at 69 cystic fibrosis (CF) centers was examined. Samples from three screening visits were processed in a single laboratory by means of standardized techniques for identification and susceptibility testing. From 1,753 pretreatment specimens, 5,128 pathogens were isolated (average, 2.9/specimen). Of the 3,936 Pseudomonas aeruginosa isolates, 56.7% were mucoid. The specimens of 125 patients (21.0%) yielded tobramycin-resistant P. aeruginosa (213 isolates); 61 (10.3%), Stenotrophomonas maltophilia; and 52 (8.7%), Alcaligenes xylosoxidans. Isolation of Burkholderia cepacia was an exclusion criterion. Only visit 3 sputum samples were cultured for gram-positive organisms and fungi (n = 465 patients); samples from 201 patients (43.2%) yielded Staphylococcus aureus (18.8% of isolates were oxacillin-resistant), and those from 114 (24.5%) yielded an Aspergillus species. Compared with the Cystic Fibrosis Foundation Patient Registry, the current study identified many more patients colonized with S. maltophilia, A. xylosoxidans, Aspergillus species, and oxacillin-resistant S. aureus, suggesting the utility of standardized processing of CF specimens.

    Title Tobacco As a Psychiatric Remedy.
    Date June 1998
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Andrew Taylor Still, M.d.: Founder of Osteopathy.
    Date February 1998
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Hydrotherapy.
    Date January 1998
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title The Genesis of Physical Culture in America.
    Date January 1998
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Phrenologist at Work, 1856.
    Date December 1997
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title South Vietnamese Healing Ceremony.
    Date December 1997
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title An Image of Distant Contact: a Blind Japanese Massage Practitioner.
    Date December 1997
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Incense over a Medicine Bundle: Hidatsa.
    Date December 1997
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Homeopathic Physician, 1855.
    Date December 1997
    Journal Journal of Alternative and Complementary Medicine (new York, N.y.)
    Title Unusual Presentations of Nontuberculous Mycobacterial Infections in Children.
    Date September 1997
    Journal The Pediatric Infectious Disease Journal
    Title Nucleotide Sequence Analysis of a Gene from Burkholderia (pseudomonas) Cepacia Encoding an Outer Membrane Lipoprotein Involved in Multiple Antibiotic Resistance.
    Date December 1996
    Journal Antimicrobial Agents and Chemotherapy
    Excerpt

    Antibiotic-resistant Burkholderia (Pseudomonas) cepacia is an important etiologic agent of nosocomial and cystic fibrosis infections. The primary resistance mechanism which has been reported is decreased outer membrane permeability. We previously reported the cloning and characterization of a chloramphenicol resistance determinant from an isolate of B. cepacia from a patient with cystic fibrosis that resulted in decreased drug accumulation. In the present studies we subcloned and sequenced the resistance determinant and identified gene products related to decreased drug accumulation. Additional drug resistances encoded by the determinant include resistances to trimethoprim and ciprofloxacin. Sequence analysis of a 3.4-kb subcloned fragment identified one complete and one partial open reading frame which are homologous with two of three components of a potential antibiotic efflux operon from Pseudomonas aeruginosa (mexA-mexB-oprM). On the basis of sequence data, outer membrane protein analysis, protein expression systems, and a lipoprotein labelling assay, the complete open reading frame encodes an outer membrane lipoprotein which is homologous with OprM. The partial open reading frame shows homology at the protein level with the C terminus of the protein product of mexB. DNA hybridization studies demonstrated homology of an internal mexA probe with a larger subcloned fragment from B. cepacia. The finding of multiple antibiotic resistance in B. cepacia as a result of an antibiotic efflux pump is surprising because it has long been believed that resistance in this organism is caused by impermeability to antibiotics.

    Title Invasion of Respiratory Epithelial Cells by Burkholderia (pseudomonas) Cepacia.
    Date November 1996
    Journal Infection and Immunity
    Excerpt

    Pulmonary infections caused by Burkholderia (Pseudomonas) cepacia are an important cause of morbidity and mortality in cystic fibrosis (CF) patients. Several features suggestive of cellular invasion and intracellular sequestration of B. cepacia in CF are persistence of infection in the face of antibiotic therapy to which the organism demonstrates in vitro susceptibility and a propensity to cause bacteremic infections in patients with CF. Epithelial cell invasion was demonstrated in vitro in A549 cells by a modified gentamicin protection assay. The kinetics of invasion appear to be saturable. Electron microscopy of invaded monolayers showed intracytoplasmic bacteria enclosed by membrane-bound vacuoles. No lysosomal fusion with these vacuoles was observed. Intraepithelial cell replication was suggested by electron microscopy and confirmed by both a quantitative assay and a visual assay. Cytochalasin D, but not colchicine, inhibited invasion, suggesting a role for microfilaments but not microtubules. The invasion phenotype in B. cepacia may be an important virulence factor for CF infections.

    Title An Affinity of Human Replication Protein A for Ultraviolet-damaged Dna.
    Date August 1996
    Journal The Journal of Biological Chemistry
    Excerpt

    Replication protein A (RPA), a heterotrimeric protein of 70-, 32-, and 14-kDa subunits, is an essential factor for DNA replication. Biochemical studies with human and yeast RPA have indicated that it is a DNA-binding protein that has higher affinity for single-stranded DNA. Interestingly, in vitro nucleotide excision repair studies with purified protein components have shown an absolute requirement for RPA in the incision of UV-damaged DNA. Here we use a mobility shift assay to demonstrate that human RPA binds a UV damaged duplex DNA fragment preferentially. Complex formation between RPA and the UV-irradiated DNA is not affected by prior enzymatic photo-reactivation of the DNA, suggesting an affinity of RPA for the (6-4) photoproduct. We also show that Mg2+ in the millimolar range is required for preferential binding of RPA to damaged DNA. These findings identify a novel property of RPA and implicate RPA in damage recognition during the incision of UV-damaged DNA.

    Title Establishment of Immortalized Alveolar Type Ii Epithelial Cell Lines from Adult Rats.
    Date January 1996
    Journal In Vitro Cellular & Developmental Biology. Animal
    Excerpt

    We developed methodology to isolate and culture rat alveolar Type II cells under conditions that preserved their proliferative capacity, and applied lipofection to introduce an immortalizing gene into the cells. Briefly, the alveolar Type II cells were isolated from male F344 rats using airway perfusion with a pronase solution followed by incubation for 30 min at 37 degrees C. Cells obtained by pronase digestion were predominantly epithelial in morphology and were positive for Papanicolaou and alkaline phosphatase staining. These cells could be maintained on an extracellular matrix of fibronectin and Type IV collagen in a low serum, insulin-supplemented Ham's F12 growth medium for four to five passages. Rat alveolar epithelial cells obtained by this method were transformed with the SV40-T antigen gene and two immortalized cell lines (RLE-6T and RLE-6TN) were obtained. The RLE-6T line exhibits positive nuclear immunostaining for the SV40-T antigen and the RLE-6TN line does not. PCR analysis of genomic DNA from the RLE-6T and RLE-6TN cells demonstrated the T-antigen gene was present only in the RLE-6T line indicating the RLE-6TN line is likely derived from a spontaneous transformant. After more than 50 population doublings, the RLE-6T cells stained positive for cytokeratin, possessed alkaline phosphatase activity, and contained lipid-containing inclusion bodies (phosphine 3R staining); all characteristics of alveolar Type II cells. The RLE-6TN cells exhibited similar characteristics except they did not express alkaline phosphatase activity. Early passage RLE-6T and 6TN cells showed a near diploid chromosome number.(ABSTRACT TRUNCATED AT 250 WORDS)

    Title Retinal Degeneration Slow (rds) in Mouse Results from Simple Insertion of a T Haplotype-specific Element into Protein-coding Exon Ii.
    Date January 1996
    Journal Genomics
    Excerpt

    Retinal degeneration slow (rds) is a semidominant mutation of mice that causes dysplasia and degeneration of rod and cone photoreceptors. Mutations in RDS, the human ortholog of the rds gene, are responsible for several inherited retinal dystrophies including a subset of retinitis pigmentosa. The normal rds locus encodes rds/peripherin, an integral membrane glycoprotein present in outer segment discs. Genomic libraries from wildtype and rds/rds mice were screened with an rds cDNA, and phage lambda clones that span the normal and mutant loci were mapped. We show that in mice, rds is caused by the insertion into exon II of a 9.2-kb repetitive genomic element that is very similar to the t haplotype-specific element in the H-2 complex. The entire element is included in the RNA products of the mutant locus. We present evidence that rds in mice represents a null allele.

    Title Comparison Study of Home Catheter Cleaning Methods.
    Date August 1995
    Journal Rehabilitation Nursing : the Official Journal of the Association of Rehabilitation Nurses
    Excerpt

    Three methods of cleaning urinary catheters for reuse at home by clients on intermittent catheterization programs were studied. Reused catheters were collected from clients, autoclaved, and then incubated in a culture of Escherichia coli broth. Three different isolates of E. coli were used at concentrations ranging from 4.8 x 10(5) to 1.0 x 10(8) colony-forming units per milliliter. The catheters were then rinsed with tap water for 1 minute and soaked in one of three cleaning solutions for 30 minutes. The three cleaning solutions studied were 0.6% hydrogen peroxide, bleach in a 1:4 solution with tap water, and betadine in a 1:2 solution with tap water. None of the cleaned catheters showed detectable growth for 48 hours after the cleaning procedure was performed.

    Title Mechanisms of Bacterial Resistance.
    Date June 1995
    Journal Pediatric Clinics of North America
    Excerpt

    Antibiotic resistance is a growing problem in clinical pediatrics. Many of the agents traditionally used to treat pediatric pathogens are becoming less effective because of increasing bacterial resistance. In addition, many more children are immunocompromised because of primary or acquired immunodeficiencies and because of advances in cancer chemotherapy and transplantation. These children are being admitted to hospitals where they may be exposed to multiply resistant nosocomial pathogens. An improved understanding of the mechanisms of antibiotic resistance and the development of treatment strategies to prevent the emergence of resistance will be increasingly required in pediatrics.

    Title Accuracy and Cost of Antibiotic Susceptibility Testing of Mixed Morphotypes of Pseudomonas Aeruginosa.
    Date August 1994
    Journal Journal of Clinical Microbiology
    Excerpt

    Chronic Pseudomonas aeruginosa colonization of the lower respiratory tract of patients with cystic fibrosis frequently results in pulmonary exacerbations requiring treatment with antimicrobial agents. Multiple morphotypes with different antibiotic susceptibilities are often isolated from a single sputum sample. Determination of MICs of antibiotics for each sputum morphotype is used to guide therapy but is time-consuming and expensive. We explored an alternative assay for determining MICs for all P. aeruginosa morphotypes cultured from a homogenized sputum sample. We sought correlations of those MICs with the MIC for the most resistant morphotypes tested separately. The MICs determined for a mixture of morphotypes correctly predicted the highest MICs (+/- one dilution) determined for isolated morphotypes 73.5% of the time. The MIC for the mixed morphotypes correctly predicted susceptibility in 90.4% of samples. In contrast, determination of the MIC for the mixture of morphotypes correctly predicted resistance in only 57.0%. For sputa containing susceptible isolates, testing the mixed culture may provide adequate susceptibility data with significant laboratory time and cost savings. However, for sputa with resistant strains, the traditional method of testing isolated morphotypes should still be used.

    Title Laryngeal Tuberculosis.
    Date February 1994
    Journal The Journal of Otolaryngology
    Title Septic Arthritis of the Temporomandibular Joint: Review of the Literature and Report of Two Cases in Children.
    Date December 1993
    Journal International Journal of Oral and Maxillofacial Surgery
    Excerpt

    Septic arthritis of the temporomandibular joint (TMJ) has a high morbidity, is infrequently reported, and has been described almost exclusively in adults. We present two cases of septic arthritis of the TMJ that occurred in children after minor blunt trauma. Literature related to septic arthritis of the TMJ was reviewed, and a composite list of cases was constructed. The most common causes were various infections of the head and neck, rheumatic joint disease, and iatrogenesis. Pathogens may gain access to the TMJ by several routes. Patients typically present with an acute, tender, monarticular arthritis with associated swelling and erythema. Malaise, nausea, and vomiting may also be present. Traumatic effusions, fractures, and neoplasms may present in a similar fashion, and mimic TMJ septic arthritis. Staphylococcus aureus is the most commonly reported pathogen and often causes permanent joint damage. Aspiration and analysis of joint fluid, as well as blood chemistry, imaging studies, and clinical impression, may assist in the diagnosis. Timely diagnosis and treatment are essential for a successful outcome; therapy should include antimicrobial agents, adequate drainage, and resting of the joint. Complications include spread of infection, postinfectious bony changes, and fibrous (or bony) ankylosis of the temporomandibular joint.

    Title Clinical Manifestations and Treatment of Pulmonary Infections in Cystic Fibrosis.
    Date November 1993
    Journal Advances in Pediatric Infectious Diseases
    Title Ozena.
    Date July 1993
    Journal The Journal of Otolaryngology
    Title Marked Phenotypic Variability in Pseudomonas Cepacia Isolated from a Patient with Cystic Fibrosis.
    Date May 1993
    Journal Journal of Clinical Microbiology
    Excerpt

    Characterization of the epidemiology of Pseudomonas cepacia colonization in cystic fibrosis is difficult because of the phenotypic variability of isolates. A single sputum culture may yield colonies which differ in morphology, antibiotic susceptibility, and pigment production. We examined serial P. cepacia isolates from a cystic fibrosis patient which the clinical laboratory identified as separate strains; these were selected on the basis of isolation date and culture site. An attempt was made to sample at multiple time points and, at a single time point, from three different culture sites. Ribotype analysis, using both the standard Southern blot technique and a recently reported method which uses the polymerase chain reaction, was used to distinguish unique P. cepacia strains. Characterization included comparison of antibiotic susceptibility, plasmid content, and outer membrane protein (OMP) patterns. rRNA analysis demonstrated that all isolates had the same ribotype, consistent with their being derivatives of the same strain. Antibiotic susceptibility testing revealed variability among both same-date and same-site isolates. Screening for plasmid DNA identified three groups of isolates; both same-date and same-site isolates demonstrated variability. OMP profiles were similar, but at least six distinct patterns were identified. For the six same-date isolates, five different OMP patterns were identified. For the 10 same-site isolates from different dates, five of the six OMP patterns were represented. We have demonstrated marked phenotypic variability in 14 strains of P. cepacia isolated from different sites and at different times from a single colonized patient. Ribotyping identified all the isolates as derivatives of a single strain; thus, the diversity of phenotypes appears to be the result of differential gene expression.

    Title Low Incidence of Citrullinemia Carriers Among Dairy Cattle of the United States.
    Date April 1993
    Journal Journal of Dairy Science
    Excerpt

    Bovine citrullinemia is an autosomal recessive disorder that is lethal in the early postnatal period. Dairy bulls from the US were screened for citrullinemia genotype with a mutation-specific assay of semen or leukocyte DNA. One heterozygote was detected among 367 US Holstein bulls tested, corresponding to an incidence of .3%; DNA sequencing showed that this bull (bull C) was heterozygous for the translation-termination mutation described as the cause of bovine citrullinemia. Tests on daughters of bull C revealed that 26 were heterozygous and 25 were homozygous normal, confirming that the condition is autosomal recessive and that bull C was heterozygous. Although bull C was among 273 bulls tested from the top 400 bulls based on Type-Production Index as of July 1990, he was not among the 90 tested from the top 100. He has fewer than 2000 offspring registered with the Holstein Association of America and has few sons in AI. Furthermore, he was culled for other reasons before his citrullinemia status was known. Accordingly, the incidence of citrullinemia carriers is low among US Holsteins, and the impact of the one carrier found on the future of the breed is expected to be minor. No carriers were found among 102 US Guernsey bulls and 53 US Jersey bulls tested.

    Title Ear Examination: the Otoscope.
    Date April 1993
    Journal The Journal of Otolaryngology
    Title Salicylate-inducible Antibiotic Resistance in Pseudomonas Cepacia Associated with Absence of a Pore-forming Outer Membrane Protein.
    Date December 1992
    Journal Antimicrobial Agents and Chemotherapy
    Excerpt

    The most common mechanism of antibiotic resistance in multiply resistant Pseudomonas cepacia is decreased porin-mediated outer membrane permeability. In some gram-negative organisms this form of antibiotic resistance can be induced by growth in the presence of weak acids, such as salicylates, which suppress porin synthesis. To determine the effects of salicylates on outer membrane permeability of P. cepacia, a susceptible laboratory strain, 249-2, was grown in 10 mM sodium salicylate. Antibiotic susceptibility and uptake, as well as outer membrane protein patterns, were compared between strain 249-2 grown with and without salicylates. The MICs of chloramphenicol, trimethoprim, ciprofloxacin, and ceftazidime were compared between organisms grown in standard and salicylate-containing medium and are as follows: chloramphenicol, 12.5 versus 100 micrograms/ml; trimethoprim, 0.78 versus 3.125 micrograms/ml; ciprofloxacin, 0.4 versus 1.56 micrograms/ml; ceftazidime, 3.125 versus 3.125 micrograms/ml. The permeability of beta-lactam antibiotics was calculated from the rate of hydrolysis of the chromogenic cephalosporin, PADAC. There was no significant difference between strains grown in the presence and absence of salicylate. By using high-pressure liquid chromatography quantitation of loss from culture medium, the effect of 10 mM salicylate on the cellular permeability of chloramphenicol was measured in strain 249-2 by introduction of a plasmid which encodes production of chloramphenicol acetyltransferase. After 1 h of incubation, 18.5% +/- 1.54% versus 70.1% +/- 3.52%, and after 2 h, 4.20% +/- 1.65% versus 41.90% +/- 2.16% remained in supernatants from organisms grown in the absence and presence of 10 mM salicylate, respectively. Outer membrane protein pattern analysis demonstrated the absence of a protein of apparent molecular weight of 40,000 when strain 249-2 was grown in the presence of 10 mM salicylate. To determine whether this protein functioned as a porin, reconstituted membrane vesicles were constructed to assess antibiotic permeability. Vesicles constructed with this salicylate-suppressible outer membrane protein (OpcS) were permeable to chloramphenicol but not to penicillin G. These findings suggest that OpcS is a selective, antibiotic-permeable porin which can be suppressed by growth in the presence of salicylate. Further investigation will be required to determine the biochemical effects of salicylate on porin synthesis.

    Title A Temperature-jump Device for Time-resolved Cryo-transmission Electron Microscopy.
    Date July 1992
    Journal Microscopy Research and Technique
    Excerpt

    We describe a temperature-jump device that permits time-resolved studies of thin cryo-transmission electron microscopy specimens. The specimen is rapidly heated to induce a change in microstructure just prior to cryo-fixation. The apparatus consists of a xenon arc lamp equipped with a shutter controlled by timing circuitry, used in conjunction with an environmental specimen preparation chamber. The specimen is heated by exposure to focused light from the lamp, and then plunged into cryogen. Using a thermocouple constructed from an electron microscope grid, we show that temperature jumps of 30-60 K are achieved with exposure times of 150-450 milliseconds. Micrographs of dimyristoyl phosphatidylcholine (DMPC) vesicles and n-docosane films, subjected to these exposures, show that the specimens are still at least 20-30 K above their initial temperature when they contact the cryogen. This method could be applied to a variety of biological and chemical systems which undergo structural changes activated by a rise in temperature.

    Title Nasal Lavage.
    Date June 1992
    Journal The Journal of Otolaryngology
    Title Characterization of the Early Ultrastructural and Biochemical Events Occurring in Dichloromethane Diphosphonate Nephrotoxicity.
    Date June 1991
    Journal Toxicologic Pathology
    Excerpt

    A chelator, dichloromethane diphosphonate (Cl2MDP), used to treat for malignancy-induced hypercalcemia, has nephrotoxic potential. An acute animal model developed to examine the mechanism was used to further characterize the renal effects. NAG enzymuria appears to be an early premonitor of injury. Ultrastructurally, an increase in size and number of protein-containing phagolysosomal reabsorption droplets in proximal convoluted tubules associated with proteinuria precedes advent of tubular cell necrosis indicating these organelles to be a potential target site for Cl2MDP in the kidney. In vitro studies using rabbit cortical tubules and rat brush border membrane vesicle preparations suggest that the renal toxicity is not due to perturbation of phosphate transport or oxidative metabolism. An operational hypothesis emerges indicating that Cl2MDP may be protein bound affecting carrier protein charge facilitating glomerular leakage with tubular accumulation via protein transport. Cl2MDP may induce critical cation perturbation at the subcellular level as the mechanism of cell death.

    Title Time-resolved Cryotransmission Electron Microscopy.
    Date March 1990
    Journal Journal of Electron Microscopy Technique
    Excerpt

    We describe a new technique, time-resolved cryotransmission electron microscopy (TRC-TEM), that can be used to study changes in microstructure occurring during dynamic processes such as phase transitions and chemical reactions. The sample is prepared on an electron microscope grid maintained at a fixed temperature in a controlled atmosphere. The dynamic process is induced on the grid by a change in pH, salt, or reactant concentration by rapid mixing with appropriate solutions. Alternatively, induction is by rapid change of specimen temperature, or by controlled evaporation of a volatile component. We call such procedures on-the-grid processing. The dynamic process is permitted to run for a defined time and then the thin-film specimen is thermally fixed by plunging into liquid ethane at its freezing point, producing a cryotransmission electron microscopy specimen. By repeating this procedure with varying delays between induction and sample fixation, we can observe transient microstructures. We demonstrate the use of TRC-TEM to study the intermediate structures that form during the transitions between L alpha, III, and HII liquid crystalline phases in phospholipid systems. We also identify several other possible applications of the technique.

    Title Isolation and Characterization of Dihydrofolate Reductase from Trimethoprim-susceptible and Trimethoprim-resistant Pseudomonas Cepacia.
    Date November 1989
    Journal Antimicrobial Agents and Chemotherapy
    Excerpt

    Trimethoprim resistance was investigated in cystic fibrosis isolates of Pseudomonas cepacia. Determination of the MIC of trimethoprim for 111 strains revealed at least two populations of resistant organisms, suggesting the presence of more than one mechanism of resistance. Investigation of the antibiotic target, dihydrofolate reductase, was undertaken in both a susceptible strain and a strain with high-level resistance (MIC, greater than 1,000 micrograms/ml). The enzyme was purified by using ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography. Specific activities, molecular weights, isoelectric points, and substrate kinetics were similar for both enzymes. However, the dihydrofolate reductase from the trimethoprim-resistant strain demonstrated decreased susceptibility to inhibition by trimethoprim and increased susceptibility to inhibition by methotrexate, suggesting that these two enzymes are not identical. We conclude that the mechanism of trimethoprim resistance in this strain with high-level resistance is production of a trimethoprim-resistant dihydrofolate reductase.

    Title Intermediates in Membrane Fusion and Bilayer/nonbilayer Phase Transitions Imaged by Time-resolved Cryo-transmission Electron Microscopy.
    Date August 1989
    Journal Biophysical Journal
    Excerpt

    Bilayer-to-nonbilayer phase transitions in phospholipids occur by means of poorly characterized intermediates. Many have proposed that membrane fusion can also occur by formation of these intermediates. Structures for such intermediates were proposed in a recent theory of these transition mechanisms. Using time-resolved cryo-transmission electron Microscopy (TRC-TEM), we have directly visualized the evolution of inverted phase micro-structure in liposomal aggregates. We have identified one of the proposed intermediates, termed an interlamellar attachment (ILA), which has the structure and dimensions predicted by the theory. We show that ILAs are likely to be the structure corresponding to "lipidic particles" observed by freeze-fracture electron microscopy. ILAs appear to assemble the inverted cubic (III) phase by formation of an ILA lattice, as previously proposed. ILAs are also observed to mediate membrane fusion in the same systems, on the same time scale, and under nearly the same conditions in which membrane fusion was observed by fluorescence methods in earlier studies. These earlier studies indicated a linkage between a membrane fusion mechanism and III phase formation. Our micrographs suggest that the same intermediate structure mediates both of those processes.

    Title Nhs Review. Emasculating the Profession.
    Date June 1989
    Journal Bmj (clinical Research Ed.)
    Title Chloramphenicol Resistance in Pseudomonas Cepacia Because of Decreased Permeability.
    Date June 1989
    Journal Antimicrobial Agents and Chemotherapy
    Excerpt

    The mechanism of chloramphenicol resistance was examined in a high-level-resistant isolate of Pseudomonas cepacia from a patient with cystic fibrosis. We investigated potential resistance mechanisms, including production of chloramphenicol acetyltransferase, ribosomal resistance, and decreased permeability. This strain (MIC, 200 micrograms/ml) had no detectable chloramphenicol acetyltransferase activity. In in vitro translation experiments in which we compared the resistant isolate with a susceptible strain of P. cepacia, inhibition of amino acid incorporation was equivalent even in organisms that were preincubated with sub-MICs of chloramphenicol. A 21.9-kilobase (kb) fragment of DNA was cloned which coded for chloramphenicol resistance; this fragment was expressed in P. cepacia but not in Escherichia coli. Quantitation of chloramphenicol uptake in the isogenic pair of susceptible and resistant organisms revealed a nearly 10-fold decrease of drug entry into the resistant strain. Comparison of isolated outer membrane proteins and lipopolysaccharide patterns identified no significant differences between the isogenic pair of organisms. We concluded that the mechanism of chloramphenicol resistance in this strain is decreased permeability.

    Title Preparation and Characterization of a Reconstituted Stratum Corneum Film As a Model Membrane for Skin Transport.
    Date April 1989
    Journal Archives of Dermatological Research
    Excerpt

    A zwitterionic surfactant, 6-eicosyldimethyl ammoniohexanoate (C20AH), completely disaggregates stratum corneum into individual cells. The cells can be cast into a film of reconstituted stratum corneum (RSC). Such films prepared from pig and human skin mimic intact human stratum corneum in microscopic, mechanical, and barrier evaluations. The films are useful as model membranes for skin transport experiments.

    Title In Vitro Activity of Second and Third Generation Cephalosporins Against Ampicillin Susceptible and Resistant Haemophilus Influenzae.
    Date March 1989
    Journal Infection
    Excerpt

    One hundred seventy-five clinical isolates of Haemophilus influenzae (including 74 beta-lactamase-producing strains) were examined for susceptibility to ampicillin, cefonicid, cefamandole, cefuroxime and cefotaxime. Cefonicid and cefamandole exhibited similar activity against ampicillin-susceptible strains (MIC90 = 0.2 mg/l for both antibiotics); cefuroxime was slightly less active (MIC90 = 0.01 mg/l). However, cefonicid, cefuroxime and cefotaxime were all more active against beta-lactamase-producing H. influenzae than cefamandole (MIC90 = 1.0 mg/l for cefonicid, MIC90 = 2.0 mg/l for cefuroxime, MIC90 = 0.01 mg/l for cefotaxime, MIC90 = 5.0 mg/l for cefamandole). One hundred twenty-five of the 175 isolates were also tested for susceptibility to cefonicid and cefamandole by disc diffusion technique and a plot of zone diameter vs. MIC was analyzed for the beta-lactamase-producing strains.

    Title Freeze-fracture-replication Using the Controlled Environment Vitrification System (cevs).
    Date January 1989
    Journal Journal of Electron Microscopy Technique
    Title Ribotype Analysis of Pseudomonas Cepacia from Cystic Fibrosis Treatment Centers.
    Date December 1988
    Journal The Journal of Pediatrics
    Title A Major Outer-membrane Protein Functions As a Porin in Haemophilus Influenzae.
    Date November 1987
    Journal Journal of General Microbiology
    Excerpt

    Porins are pore-forming outer-membrane proteins which serve as a non-specific pathway for the entry of hydrophilic molecules into Gram-negative bacteria. We studied four strains of Haemophilus influenzae that had decreased permeability to chloramphenicol associated with diminished quantities of a 40 kDa major outer-membrane protein. Isogenic pairs of organisms containing and lacking this protein were compared. The latter strains grew more slowly and were less permeable to sucrose and raffinose. They were also more resistant to multiple hydrophilic antibiotics than an isogenic strain containing the 40 kDa protein and were less permeable to penicillin G and chloramphenicol. We conclude that the 40 kDa outer-membrane protein functions as a porin in H. influenzae.

    Title Pediatric Urinary Tract Infection. Diagnosis, Classification, and Significance.
    Date November 1987
    Journal Pediatric Clinics of North America
    Excerpt

    The initial task is to establish the diagnosis of a urinary tract infection. The clinical setting, method of specimen collection, bacterial colony count, and species are all important considerations. Next, the infection is classified as complicated or uncomplicated. Complicated infections require hospitalization and parenteral antibiotic therapy. Appropriate imaging studies are imperative to determine whether urologic intervention is necessary. All children with well-documented urinary tract infections deserve diagnostic evaluation, regardless of sex or presence of systemic symptoms.

    Title Chloramphenicol Accumulation by Haemophilus Influenzae.
    Date July 1987
    Journal Antimicrobial Agents and Chemotherapy
    Excerpt

    The mechanism of chloramphenicol transport into susceptible strains of Haemophilus influenzae cells has not been reported previously. We examined apparent uptake of chloramphenicol by bacterial cells by using high-pressure liquid chromatography to quantitate drug disappearance from liquid media. Cell-associated chloramphenicol concentration is 1,000-fold greater than the extracellular drug concentration. Under incubation conditions associated with chloramphenicol disappearance from media, cellular protein synthesis was inhibited; however, if accumulation was inhibited, protein synthesis occurred in the presence of the drug. Chloramphenicol uptake appeared saturable (Km = 0.96 mM, Vmax = 0.9 mumol/min per mg of protein) and energy dependent: disappearance from media was markedly decreased by 2,4-dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone, compounds which disrupt the proton motive force. Uptake occurred only in median which can support growth and was dependent upon temperature and pH. Drug accumulation was minimally affected by inhibitors of electron transport or by gentamicin and puromycin, both inhibitors of protein synthesis. The rate of disappearance was inhibited by SCH24893, a fluorinated chloramphenicol analog which also inhibits protein synthesis. We conclude that chloramphenicol accumulation by H. influenzae occurs by energy-dependent transport.

    Title Gastric Spirillosis in Beagles.
    Date July 1987
    Journal American Journal of Veterinary Research
    Excerpt

    Light microscopic, ultrastructural, and microbiologic evaluations were performed on stomachs from 30 healthy laboratory-reared Beagles. Spiral-shaped microorganisms were seen in the gastric glands and parietal cell canaliculi of all the dogs. Organisms were most numerous in the cardia and in the region of the fundic-pyloric junction. Lymphoreticular hyperplasia, dilatation of parietal cell canaliculi, and degeneration of individual parietal cells (rarely seen) were the only morphologic alterations seen. Organisms were helical, had tufts of flagella at each end, and were approximately 0.5 X 7.0 micron; some had a distinct axial fibril (indicating two distinct forms of the organism). Attempts to propagate a viable culture of the organism were not successful. The organism most closely resembled those of the genus Spirillum. Because the organism was commonly found in the gastric mucosa of healthy Beagles, it probably should be considered part of the natural gastric flora of dogs.

    Title Decalin-induced Nephrotoxicity: Light and Electron Microscopic Examination of the Effects of Oral Dosing on the Development of Kidney Lesions in the Rat.
    Date April 1987
    Journal Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association
    Excerpt

    Male and female Fischer 344 rats were given decalin by oral gavage for 5 or 12 consecutive days in order to determine whether oral dosing would result in light microscopically evident renal effects that were comparable to those that have been observed after inhalation exposure. Decalin (in corn oil vehicle) was administered at doses of 0, 0.1, 0.5, 1.0 or 2.0 g/kg body weight to male rats, and 0, 1.0, 1.5, 1.75 or 2.0 g/kg to female rats. Biopsies of the kidneys of selected control and high-dose male rats were taken for examination by electron microscopy. Sections of kidneys from all control and treated rats were examined by light microscopy. The kidneys of all male control rats contained minimal levels of hyaline droplets within the cytoplasm of proximal convoluted tubule (PCT) epithelial cells. Decalin-induced alterations in the kidneys of male rats included an exacerbation of the hyaline droplet/globule levels found in controls and the formation of granular casts in the outer zone of the renal medulla. The exacerbated formation of hyaline droplets was characterized light microscopically by a marked dose-related increase in the number and size of individual droplets/globules and ultrastructurally by a marked increase in the size range of, and the presence of crystalline inclusions in, the PCT epithelial cell phagolysosomal populations. No other ultrastructural alterations occurred that differentiated treated male rats from control males. The formation of granular casts was dose and time related, occurring in 60% of male rats given 0.5 g decalin/kg for 12 days and in 100% of those given 1.0 g decalin/kg for 12 days. Light microscopy revealed no differences between the kidneys of control and decalin-treated female rats, and no hyaline droplets or granular casts were observed in the kidneys of any female rat killed after 5 or 12 days. These results were in agreement with those of inhalation studies and provide additional evidence that the formation of hyaline droplets in response to exposure to volatile hydrocarbons may be unique to the male rat.

    Title Cloning and Expression in Escherichia Coli of a Gene Encoding Nonenzymatic Chloramphenicol Resistance from Pseudomonas Aeruginosa.
    Date July 1986
    Journal Antimicrobial Agents and Chemotherapy
    Excerpt

    High-level chloramphenicol resistance in Pseudomonas aeruginosa may be due to enzymatic inactivation, ribosomal mutation, or a permeability barrier. We investigated the nonenzymatic resistance mechanism encoded by Tn1696, a transposon found in P. aeruginosa. A 1-megadalton DNA fragment from Tn1696 was cloned which mediated expression of chloramphenicol resistance in Escherichia coli. Comparison of the effects of chloramphenicol on in vitro translation revealed no difference between the susceptible recipient strain and the resistant transformant containing the cloned gene. The rate of chloramphenicol uptake was slower in the resistant strain, suggesting a permeability barrier to the antibiotic. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membranes demonstrated the absence of a 50,000-dalton protein in the resistant strain. DNA homology was evident between Tn1696 and chloramphenicol-resistant isolates of Haemophilus influenzae possessing altered outer membrane permeability. We conclude that chloramphenicol resistance encoded by Tn1696 is due to a permeability barrier and hypothesize that the gene from P. aeruginosa may share a common ancestral origin with these genes from other gram-negative organisms.

    Title Effect of Tobramycin on Protein Synthesis in 2-deoxystreptamine Aminoglycoside-resistant Clinical Isolates of Haemophilus Influenzae.
    Date July 1986
    Journal Antimicrobial Agents and Chemotherapy
    Excerpt

    Clinical isolates of Haemophilus influenzae resistant to a broad range of 2-deoxystreptamine aminoglycosides (2-DAM) were studied. The gene responsible for resistance could be mobilized by transformation into a 2-DAM susceptible laboratory strain of H. influenzae, enabling isogenic comparisons. The transformants had the same resistance phenotype as the parental strains. There was close linkage between 2-DAM resistance and streptomycin resistance, a chromosomal marker, but weak linkage between 2-DAM and erythromycin resistance. Resistant transformants exhibited a decreased accumulation of gentamicin due to the absence of the rapid, energy-dependent phase of uptake. Resistance was not through metabolic inactivation of the antibiotic; no aminoglycoside-acetylating, -adenylylating, or -phosphorylating activity was detected in the wild-type strains or in the 2-DAM-resistant transformants. Protein synthesis in 2-DAM-susceptible H. influenzae strains increased in the presence of low (1 microgram/ml) and moderate (50 micrograms/ml) concentrations of tobramycin. With higher concentrations (100 and 500 micrograms/ml), protein synthesis was progressively inhibited. In contrast, protein synthesis in 2-DAM-resistant clinical isolates and transformants was inhibited by 1 microgram of tobramycin per ml, and inhibition increased with higher drug concentrations. Since the stimulating effect of low concentrations of tobramycin in susceptible H. influenzae strains is probably due to misreading, these findings suggest that 2-DAM-resistant strains of H. influenzae have reduced sensitivity to misreading, indicating that altered ribosomes are responsible for the resistance.

    Title Primary Meningococcal Pneumonia Diagnosed by Pleural Fluid Culture.
    Date March 1986
    Journal American Journal of Diseases of Children (1960)
    Title A Permeability Barrier As a Mechanism of Chloramphenicol Resistance in Haemophilus Influenzae.
    Date April 1985
    Journal Antimicrobial Agents and Chemotherapy
    Excerpt

    Chloramphenicol resistance in Haemophilus influenzae occurs most frequently via plasmid-mediated chloramphenicol acetyltransferase production. We studied four strains with high-level chloramphenicol resistance (MIC greater than 20 micrograms/ml) which did not have detectable chloramphenicol acetyltransferase activity. The chloramphenicol resistance determinant was transformed into a chloramphenicol-susceptible laboratory H. influenzae strain from each of the four wild-type strains, enabling isogenic comparisons. By thin-layer chromatography and a bioassay, there was no evidence of non-chloramphenicol acetyltransferase modification of chloramphenicol. In vitro protein synthesis in the presence of chloramphenicol was equivalently inhibited in the chloramphenicol-resistant transformants and in the susceptible recipient. Chloramphenicol uptake by these strains during logarithmic growth was compared by high-pressure liquid chromatographic quantitation; at chloramphenicol concentrations of 5, 10, and 20 micrograms/ml the four transformants showed a decreased rate of uptake of chloramphenicol compared with the isogenic chloramphenicol-susceptible recipient. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of outer membrane proteins revealed a markedly diminished 40-kilodalton protein in the resistant transformants. We propose that the mechanism of chloramphenicol resistance in these strains is a relative permeability barrier due to the loss of an outer membrane protein.

    Title No Evidence for Chromosomal Mosaicism in Multiple Tissues of 10 Patients with 45, Xo Turner Syndrome.
    Date March 1979
    Journal Clinical Genetics
    Excerpt

    Why the frequency of spontaneous abortions among monosomy X conceptuses is 98% while the postnatal course of Turner syndrome is relatively benign has not been understood. One explanation could be that mosaicism for a euploid cell line confers viability and that those 2% of 45,XO zygotes surviving in utero have some degree of mosaicism. We thus reasoned that if the non-mosaic 45,XO karyotype is lethal, a thorough study of living Turner syndrome patients might reveal a much higher frequency of mosaicism than the 30--40% reported. Ten adult women with a 45,XO leukocyte karyotype were investigated, looking at five tissue types from all three germ layers: buccal mucosa and hair from ectoderm, urinary epithelium from endoderm and ectoderm, and lymphocytes and skin fibroblasts from mesoderm. We were unable to confirm mosaicism in these patients, although in 2 out of 10 there was the suggestion of a small percentage of euploid cells in skin and blood karyotypes.

    Title Open Pulmonary Biopsy. Nineteen-year Experience with 416 Consecutive Operations.
    Date February 1976
    Journal Chest
    Excerpt

    Four hundred and sixteen open pulmonary biopsies through limited thoracotomies are reported. Tissue sufficient for diagnosis was obtained in all cases. Case selection, operative technique, spectrum of diagnoses, complications, and comparisons with other techniques are defined. Diagnoses by category were as follows: occupational, 105 patients (25 percent); neoplastic disease, 80 patients (19 percent); specific histologic diagnosis, (ie, sarcoidosis), 70 patients (17 percent); specific infection, 23 patients (6 percent); vascular diagnosis, 16 patients (4 percent); and nonspecific pulmonary disease, 122 patients (29 percent). Pneumothorax, minor in most cases, was the most common complication. It occurred in 97 (23 percent) of the patients, but only 24 (6 percent) required the placement of a chest tube. Pleural effusion occurred in 106 patients (25 percent) and was minor. Hemothorax occurred in two (0.5 percent) and superficial wound infection in three (0.7 percent). Overall mortality was 4.5 percent (19 patients). Only two deaths (0.4 percent) were related to the procedure. Open pulmonary biopsy remains our diagnostic method of choice in diffuse lung disease of undetermined etiology.

    Title Some Personality Attributes of Volunteers and of Nonvolunteers for Psychological Experimentation.
    Date May 1974
    Journal The Journal of Social Psychology
    Title Delinquents Failed by the System.
    Date August 1971
    Journal Special Education
    Title Cepacia-like Syndrome Caused by Burkholderia Multivorans.
    Date
    Journal The Canadian Journal of Infectious Diseases = Journal Canadien Des Maladies Infectieuses
    Excerpt

    The variable severity of Burkholderia cepacia complex infections in cystic fibrosis (CF) has recently been ascribed to differences in the virulence between genomovars. Specifically, genomovar III isolates have been associated with higher transmission rates and adverse outcomes compared to other B cepacia genomovars, and consequently further segregation between genomovar III and non-genomovar III B cepacia infected patients is advocated in some centres. The important role of non-genomovar III isolates is presented in the context of a clinical case whereby a patient with long-standing pulmonary infection with B multiovorans developed bacteremic infection reminiscent of the fatal 'cepacia syndrome'.

    Title Impact of Pseudomonas and Staphylococcus Infection on Inflammation and Clinical Status in Young Children with Cystic Fibrosis.
    Date
    Journal The Journal of Pediatrics
    Excerpt

    OBJECTIVE: To assess the effects of Pseudomonas aeruginosa and Staphylococcus aureus infection on lower airway inflammation and clinical status in young children with cystic fibrosis (CF). STUDY DESIGN: We studied 111 children age < 6 years who had 2 P aeruginosa-positive oropharyngeal cultures within 12 months. We examined bronchoalveolar lavage fluid (BALF) inflammatory markers (ie, cell count, differential, interleukin [IL]-8, IL-6, neutrophil elastase), CF-related bacterial pathogens, exotoxin A serology, and clinical indicators of disease severity. RESULTS: Young children with CF with both upper and lower airway P aeruginosa infection had higher neutrophil counts, higher IL-8 and free neutrophil elastase levels, increased likelihood of positive exotoxin A titers, and lower Shwachman scores compared with those with positive upper airway cultures only. S aureus was associated with increased lower airway inflammation, and the presence of both P aeruginosa and S aureus had an additive effect on concentrations of lower airway inflammatory markers. BALF markers of inflammation were increased with the number of different bacterial pathogens detected. CONCLUSIONS: Young children with CF who have upper and lower airway P aeruginosa infection have increased endobronchial inflammation and poorer clinical status compared with those with only upper airway P aeruginosa infection. The independent and additive effects of S aureus on inflammation support the significance of polymicrobial infection in early CF lung disease.

    Title Pseudomonas Aeruginosa Lasr Mutants Are Associated with Cystic Fibrosis Lung Disease Progression.
    Date
    Journal Journal of Cystic Fibrosis : Official Journal of the European Cystic Fibrosis Society
    Excerpt

    BACKGROUND: Pseudomonas aeruginosa with mutations in the transcriptional regulator LasR chronically infect the airways of people with cystic fibrosis (CF), yet the prevalence and clinical implications of lasR mutant infection are unknown. METHODS: In an exploratory study, we screened 166 P. aeruginosa isolates from 58 CF patients for LasR inactivation and mucoidy, and compared clinical characteristics among source patients. RESULTS: lasR mutation prevalence was comparable to that of mucoidy, the best-described CF-adapted phenotype, but affected patients were on average approximately 2 years younger. In a regression analysis, lung function decline with age was worse among patients with lasR mutant infection than in those without, similar to the effect of mucoidy. CONCLUSIONS: Culture positivity for lasR mutant P. aeruginosa may serve as a marker of early CF adaptive change of prognostic significance. Furthermore, as LasR inactivation alters susceptibility to antibiotics, infection with lasR mutant P. aeruginosa may impact response to therapy.

    Title Randomized Trial of Biofilm Testing to Select Antibiotics for Cystic Fibrosis Airway Infection.
    Date
    Journal Pediatric Pulmonology
    Excerpt

    In cystic fibrosis (CF), conventional antibiotic susceptibility results correlate poorly with clinical outcomes. We hypothesized that biofilm testing would more accurately reflect the susceptibilities of bacteria infecting CF airways.

    Title A Rare Continual Flowering Strategy and Its Influence on Offspring Quality in a Gynodioecious Plant.
    Date
    Journal American Journal of Botany
    Excerpt

    The majority of angiosperms have a single annual bout of reproduction; species that flower continually throughout the year are rare. Ochradenus baccatus is a gynodioecious, desert shrub whose principal flowering period is associated with the winter rains, although large individuals also remain in flower during the hot, dry summer. The goal of this study was to examine the reproductive consequences of continual flowering in a large population of O. baccatus in Israel. Over the two years of this study, 60% of individuals flowered continuously. The number of fruit and seeds per fruit were greater in winter. Winter seeds were ∼12% heavier than summer seeds and had significantly higher germination rates (80 vs. 60%, respectively). Although summer seeds were smaller and less likely to germinate, we propose that the benefit derived from their production lies in their ability to capitalize on the first winter rains. These early rain events provide a head start on establishment and growth in the hostile desert environment. Plants that delay reproduction until the onset of rains risk having their offspring face the dry conditions of spring and summer.

    Title Initial Pseudomonas Aeruginosa Treatment Failure is Associated with Exacerbations in Cystic Fibrosis.
    Date
    Journal Pediatric Pulmonology
    Excerpt

    The risk of pulmonary exacerbation following Pseudomonas aeruginosa (Pa) acquisition in children with cystic fibrosis (CF) is unknown.

    Title Respiratory Viruses in Children with Cystic Fibrosis: Viral Detection and Clinical Findings.
    Date
    Journal Influenza and Other Respiratory Viruses
    Excerpt

    Please cite this paper as: Burns et al. (2011) Respiratory viruses in children with cystic fibrosis: viral detection and clinical findings. Influenza and Other Respiratory Viruses 6(3), 218-223. Background  Viral detection from different respiratory sample types in children with cystic fibrosis (CF) is facilitated by available molecular methods, but optimum sampling strategies have not been identified. In addition, associations between viral detection and respiratory symptoms are not well described. Objectives  Study goals were to compare molecular detection of viruses from concurrent upper airway and sputum samples in children with CF and to describe relative frequency of respiratory viral infections and identify potential clinical associations. Methods  We conducted a 2-year prospective surveillance study in 44 children with CF aged 6-18 years. Upper airway and sputum samples were collected quarterly and during pulmonary exacerbations and tested for respiratory syncytial virus (RSV), influenza viruses, parainfluenza viruses types 1-4, human metapneumovirus, coronaviruses, rhinoviruses, and adenoviruses. Physical exams and symptom surveys were used to identify respiratory signs and symptoms. Results  Upper airway samples were collected at 359 visits; concordance of PCR-based viral detection was examined in a subset of paired upper airway and sputum samples from 21 participants at 92 visits. Rhinovirus was the most commonly detected virus (23·1% overall), and rhinovirus detection was the same for both sample types (21·7% each). Sensitivity and specificity for the detection of rhinovirus in sputum relative to upper airway sampling were 70% and 91·7%, respectively. Respiratory symptoms associated with rhinovirus detection included increased cough, increased nasal congestion, increased sputum production, and wheezing. Conclusions  A relatively high frequency of rhinovirus detection was observed by either upper airway or sputum samples, and clinical findings suggest a significant-associated symptom burden.

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