Family Physicians, General Practitioner
27 years of experience

Accepting new patients
Buenaventura Lakes
Orlando Family Physicians
104 Buenaventura Blvd
Kissimmee, FL 34743
407-344-9959
Locations and availability (2)

Education ?

Medical School
Universidad De San Carlos (1983)
Foreign school

Publications & Research

Dr. Hernandez has contributed to 40 publications.
Title Same-sex Cohabitation Under the Effects of Quinpirole Induces a Conditioned Socio-sexual Partner Preference in Males, but Not in Female Rats.
Date December 2011
Journal Pharmacology, Biochemistry, and Behavior
Excerpt

The effects of the dopamine D2-type receptor agonist quinpirole (QNP) were examined on the development of conditioned same-sex partner preference induced by cohabitation in rats. In Experiment 1, males received either saline or QNP (1.25mg/kg) and cohabited during three trials with almond-scented stimulus males that were sexually naïve. In Experiment 2, males received six trials, and in Experiment 3 received three trials with sexually expert stimulus males. During a final drug-free preference test, males chose between the familiar or a novel male partner. In Experiments 1, 2 and 3 only QNP-treated males displayed a social preference for the familiar male, observed with more time spent together. In Experiment 3 males also displayed a sexual preference observed with more non-contact erections when were exposed to their male partner. In Experiment 4 we tested the effects on OVX, E+P primed females that received 1 systemic injection of either saline or QNP during three conditioning trials. In Experiment 5, females received 2 injections 12-h apart during each trial. Results indicated that both saline and QNP-treated females failed to develop partner preference. These data demonstrate that enhanced D2-type receptor activity during cohabitation facilitates the development of conditioned same-sex partner preference in males, but not in female rats. We discuss the implications for same-sex partner preferences.

Title Histological Modifications of the Rat Prostate Following Transection of Somatic and Autonomic Nerves.
Date December 2010
Journal Anais Da Academia Brasileira De Ciências
Excerpt

It is known that hormones influence significantly the prostate tissue. However, we reported that mating induces an increase in androgen receptors, revealing a neural influence on the gland. These data suggested that somatic afferents (scrotal and genitofemoral nerves) and autonomic efferents (pelvic and hypogastric nerves) could regulate the structure of the prostate. Here we assessed the role of these nerves in maintaining the histology of the gland. Hence, afferent or efferent nerves of male rats were transected. Then, the ventral and dorsolateral regions of the prostate were processed for histology. Results showed that afferent transection affects prostate histology. The alveoli area decreased and increased in the ventral and dorsolateral prostate, respectively. The epithelial cell height increased in both regions. Efferent denervation produced dramatic changes in the prostate gland. The tissue lost its configuration, and the epithelium became scattered and almost vanished. Thus, afferent nerves are responsible for spinal processes pertaining to the trophic control of the prostate, activating its autonomic innervation. Hence, our data imply that innervation seems to be synergic with hormones for the healthy maintenance of the prostate. Thus, it is suggested that some prostate pathologies could be due to the failure of the autonomic neural pathways regulating the gland.

Title Acute Effects of 2-methoxyestradiol on Endothelial Aortic No Release in Male and Ovariectomized Female Rats.
Date September 2010
Journal Nitric Oxide : Biology and Chemistry / Official Journal of the Nitric Oxide Society
Excerpt

The endogenous metabolites of 17beta-estradiol are thought to have protective vascular effects, especially in males and estrogen-deprived females. The present study evaluated the acute in vitro effects of the active metabolite 2-methoxyestradiol on endothelial NO release from ovariectomized female and intact male and female rat aortas. NO was measured electrochemically by differential normal pulse amperometry using carbon fiber microsensors, and also by fluorescence microscopy using 4,5-diaminofluorescein diacetate. 2-Methoxyestradiol alone induced a maintained increase in endothelial NO release in male and ovariectomized rats that was reduced by pretreatment with L-NAME. NO release induced by calcium ionophore alone (A23187) was lower in aortas from ovariectomized rats than from intact females, indicating that estrogen deprivation induces endothelial dysfunction. Pretreatment of aortas with 2-methoxyestradiol potentiated significantly the A23187-induced-NO release in ovariectomized as well as in males, but not in intact females. This potentiation was reduced or abolished by L-NAME. 2-Methoxyestradiol potentiated the vasodilatory effect of A23187 on intestinal arterioles, and also increased intestinal tissular laser-Doppler blood flow signal. These results demonstrate that 17beta-estradiol and its active metabolite 2-methoxyestradiol increase basal aortic endothelial NO production and also cause a potentiation of the calcium ionophore-stimulated NO release in male and ovariectomized, while it has no effects on intact females. 2-Methoxyestradiol appears to be a promising pharmacological agent capable of improving endothelial function in men and postmenopausal women.

Title Multiunit Recording of the Cerebellar Cortex, Inferior Olive, and Fastigial Nucleus During Copulation in Naive and Sexually Experienced Male Rats.
Date July 2010
Journal Cerebellum (london, England)
Excerpt

The sexual behavior of male rats constitutes a natural model to study learning of motor skills at the level of the central nervous system. We previously showed that sexual behavior increases Fos expression in granule cells at lobules 6 to 9 of the vermis cerebellum. Herein, we obtained multiunit recordings of lobules 6a and 7 during the training period of naive subjects, and during consecutive ejaculations of expert males. Recordings from both lobules and the inferior olive showed that the maximum amplitude of mount, intromission, and ejaculation signals were similar, but sexual behavior during training tests produced a decrease in the amplitude for mount and intromission signals. The fastigial nucleus showed an inverse mirror-like response. Thus, the cerebellum is involved in the neural basis of sexual behavior and the learning of appropriate behavioral displays during copulation, with a wiring that involves the cerebellar cortex, inferior olive, and fastigial nucleus.

Title Evaluation of the Effect of Selective Serotonin-reuptake Inhibitors on Lymphocyte Subsets in Patients with a Major Depressive Disorder.
Date April 2010
Journal European Neuropsychopharmacology : the Journal of the European College of Neuropsychopharmacology
Excerpt

To date, only the effect of a short-term antidepressant treatment (<12 weeks) on neuroendocrinoimmune alterations in patients with a major depressive disorder has been evaluated. Our objective was to determine the effect of a 52-week long treatment with selective serotonin-reuptake inhibitors on lymphocyte subsets. The participants were thirty-one patients and twenty-two healthy volunteers. The final number of patients (10) resulted from selection and course, as detailed in the enrollment scheme. Methods used to psychiatrically analyze the participants included the Mini-International Neuropsychiatric Interview, Hamilton Depression Scale and Beck Depression Inventory. The peripheral lymphocyte subsets were measured in peripheral blood using flow cytometry. Before treatment, increased counts of natural killer (NK) cells in patients were statistically significant when compared with those of healthy volunteers (312+/-29 versus 158+/-30; cells/mL), but no differences in the populations of T and B cells were found. The patients showed remission of depressive episodes after 20 weeks of treatment along with an increase in NK cell and B cell populations, which remained increased until the end of the study. At the 52nd week of treatment, patients showed an increase in the counts of NK cells (396+/-101 cells/mL) and B cells (268+/-64 cells/mL) compared to healthy volunteers (NK, 159+/-30 cells/mL; B cells, 179+/-37 cells/mL). We conclude that long-term treatment with selective serotonin-reuptake inhibitors not only causes remission of depressive symptoms, but also affects lymphocyte subset populations. The physiopathological consequence of these changes remains to be determined.

Title Decreased Muscle Strength Relates to Self-reported Stooping, Crouching, or Kneeling Difficulty in Older Adults.
Date January 2010
Journal Physical Therapy
Excerpt

Bending down and kneeling are fundamental tasks of daily living, yet nearly a quarter of older adults report having difficulty performing or being unable to perform these movements. Older adults with stooping, crouching, or kneeling (SCK) difficulty have demonstrated an increased fall risk. Strength (force-generating capacity) measures may be useful for determining both SCK difficulty and fall risk.

Title An Interactive Tool for Visualizing Design Heterogeneity in Clinical Trials.
Date January 2010
Journal Amia ... Annual Symposium Proceedings / Amia Symposium. Amia Symposium
Excerpt

Clinical questions are often studied by randomized clinical trials (RCTs) of heterogeneous design. Systematic reviewers and trial designers need to compare the design and results across these trials. If trial information is available in computer processable form, computer-based visualization techniques can provide cognitive support for such comparisons. CTeXplorer offers systematic reviewers and trial designers a tool to better and more quickly understand design heterogeneity in RCTs. CTeXplorer supports dynamic queries on eligibility criteria, interventions, and outcomes in three linked views. We tested CTeXplorer for displaying 12 RCTs on prevention of mother-to-child transmission of HIV. Three target users found the representation and organization of information intuitive and easy to learn. They were able to use CTeXplorer to achieve a quick cognitive overview of a heterogeneous group of RCTs. This work shows the benefit of capturing trial information in computable form. Future work includes leveraging ontologies to enhance CTeXplorer visualizations.

Title Characteristics of Older Adults with Self-reported Stooping, Crouching, or Kneeling Difficulty.
Date September 2008
Journal The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
Excerpt

BACKGROUND: Stooping, crouching, and kneeling (SCK) are fundamental components of daily living tasks, and nearly a quarter of older adults report a lot of difficulty or inability to perform these movements. This study examined characteristics associated with SCK difficulty to explore underlying mechanisms and remediation strategies. METHODS: One hundred eighty-four older adults with no, low, or high SCK difficulty underwent a comprehensive laboratory visit at the University of Michigan. RESULTS: Twenty-one percent of participants (n = 39) reported a lot of difficulty or inability to stoop, crouch, or kneel. Characteristics independently associated with increasing SCK difficulty were self-reported leg joint limitations, (odds ratio [OR] = 3.84; 95% confidence interval [CI], 1.64-9.01), Activities-specific Balance Confidence Scale score (OR = 0.97; 95% CI, 0.95-0.99), and knee extension strength (OR = 0.72; 95% CI, 0.55-0.94). CONCLUSIONS: Increasing SCK difficulty is associated with balance confidence as well as leg limitations. Remediation of SCK difficulty will likely require a program that encompasses both behavioral and physical issues.

Title Fos Expression at the Cerebellum Following Non-contact Arousal and Mating Behavior in Male Rats.
Date April 2008
Journal Physiology & Behavior
Excerpt

The cerebellum is considered a center underlying fine movements, cognition, memory and sexual responses. The latter feature led us to correlate sexual arousal and copulation in male rats with neural activity at the cerebellar cortex. Two behavioral paradigms were used in this investigation: the stimulation of males by distant receptive females (non-contact sexual stimulation), and the execution of up to three consecutive ejaculations. The vermis area of the cerebellum was removed following behavioral experiments, cut into sagittal sections, and analyzed with Fos immunohistochemistry to determine neuronal activation. At the mid-vermis region (sections from the midline to 0.1 mm laterally), non-contact stimulation significantly increased the activity of granule neurons. The number of activated cells increased in every lobule, but lobules 1 and 6 to 9 showed the greatest increment. In sexual behavior tests, males reaching one ejaculation had a high number of activated neurons similar to those counted after non-contact stimulation. However, two or three consecutive ejaculations showed a smaller number of Fos-ir cells. In contrast to the mid-vermis region, sections farthest from the midline (0.1 to 0.9 mm laterally) revealed that only lobule 7 expressed activated neurons. These data suggest that a well-delineated group of granule neurons have a sexual biphasic response at the cerebellar vermis, and that Fos in them is under an active degradation mechanism. Thus, they participate as a neural substrate for male rat sexual responses with an activation-deactivation process corresponding with the sensory stimulation and motor performance occurring during copulation.

Title Characteristics of Ejaculated Rat Semen After Lesion of Scrotal Nerves.
Date July 2007
Journal Physiology & Behavior
Excerpt

The scrotum, representing the pouch surrounding the testes and their associated structures, plays a significant role in maintaining the gonad at a temperature lower than that of the body. Although thermoregulation of the testes has been ascribed as a main function of the scrotum, here we found that mechanical stimulation of the scrotum is important during mating to facilitate the appropriate expulsion of semen during ejaculation. Previously we showed that the scrotal skin area is innervated by two nerve branches, the proximal (Psb) and distal (Dsb) scrotal branches which supply the proximal or distal half of the scrotum, respectively. The sensory field of each nerve is testosterone-dependent. The decreased androgen levels following castration reduce the sensitive area to mechanical stimuli that can be restored following exogenous administration of the hormone. Here, we tested the effect of scrotal nerve transection on sexual parameters of experienced male rats. Data show that lesion of PSb or DSb alone or combined did not affect the execution of sexual behavior. However, these lesions significantly reduced the proportion of males that expelled semen during ejaculation, with that semen showing a reduced quantity of sperm. Thus, scrotal nerves are important in reproduction not for the appropriate display of sexual behavior, but for the expulsion of a normal quantity of semen and number of sperm during ejaculation. Our suggestion is that scrotal afferents trigger spinal reflexes to activate autonomic efferents supplying the male reproductive tract for the control of seminal emission.

Title A Study of the Prostate, Androgens and Sexual Activity of Male Rats.
Date April 2007
Journal Reproductive Biology and Endocrinology : Rb&e
Excerpt

BACKGROUND: The prostate is a sexual gland that produces important substances for the potency of sperm to fertilize eggs within the female reproductive tract, and is under complex endocrine control. Taking advantage of the peculiar behavioral pattern of copulating male rats, we developed experimental paradigms to determine the influence of sexual behavior on the level of serum testosterone, prostate androgen receptors, and mRNA for androgen receptors in male rats displaying up to four consecutive ejaculations. METHODS: The effect of four consecutive ejaculations was investigated by determining levels of (i) testosterone in serum by solid phase RIA, (ii) androgen receptors at the ventral prostate with Western Blots, and (iii) androgen receptors-mRNA with RT-PCR. Data were analyzed with a one-way ANOVA followed by a post hoc application of Dunnett's test if required. RESULTS: The constant execution of sexual behavior did not produce any change in the weight of the ventral prostate. Serum testosterone increased after the second ejaculation, and remained elevated even after four ejaculations. The androgen receptor at the ventral prostate was higher after the first to third ejaculations, but returned suddenly to baseline levels after the fourth ejaculation. The level of mRNA increased after the first ejaculation, continued to increase after the second, and reached the highest peak after the third ejaculation; however, it returned suddenly to baseline levels after the fourth ejaculation. CONCLUSION: Four consecutive ejaculations by sexually experienced male rats had important effects on the physiological responses of the ventral prostate. Fast responses were induced as a result of sexual behavior that involved an increase and decrease in androgen receptors after one and four ejaculations, respectively. However, a progressive response was observed in the elevation of mRNA for androgen receptors, which also showed a fast decrease after four ejaculations. All of these changes with the prostate gland occurred in the presence of a sustained elevation of testosterone in the serum that started after two ejaculations. A consideration of these fast-induced changes suggests that the nerve supply plays a key role in prostate physiology during the sexual behavior of male rats.

Title Denitrification Potential and Organic Matter As Affected by Vegetation Community, Wetland Age, and Plant Introduction in Created Wetlands.
Date February 2007
Journal Journal of Environmental Quality
Excerpt

Denitrification potential (DP) and organic matter (OM) in soils were compared in three different vegetation communities-emergent macrophyte, open water, and forested edge-in two 10-yr-old created riverine wetlands. Organic matter, cold water-extractable organic matter (CWEOM), anaerobic mineralizable carbon (AnMC), and DP varied significantly (P<0.05) among vegetation communities. The surface (0 to 9 cm) soils in the emergent macrophyte community (EMC) showed highest DP (0.07+/-0.01 mg N h-1 kg-1), OM (84.90+/-5.60 g kg-1), CWEOM (1.12+/-0.20 g kg-1), and AnMC (1.50+/-0.10 mg C h-1 kg-1). In the deeper layer (9 to 18 cm), DP and CWEOM (0.04+/-0.01 mg N h-1 kg-1 and 1.13+/-0.20 g kg-1, respectively) were significantly higher in the open water community (OWC) than in the emergent macrophyte and forested edge communities. Plant introduction did not affect DP or OM content and characteristics. After 10 yr of wetland development, mean DP increased 25-fold in the surface layer (from 0.002 to 0.053 mg N h-1 kg-1); OM content more than doubled to 90.80+/-19.22 g kg-1, and CWEOM and HWEOM increased 2.5 and 2.7 times respectively from 1993 (prewetland conditions) to 2004. Humic acids were the most abundant form of OM in 2004 and 1993 samples. Significant (P<0.05) positive relationships between DP and OM, CWEOM, and AnMC were found in the surface layer; in the 9- to 18-cm layer, significant positive relationships were found between DP and CWEOM and AnMC.

Title Effect of a Calcium Hydroxide-based Root Canal Dressing on Periapical Repair in Dogs: a Histological Study.
Date October 2006
Journal Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics
Excerpt

To compare the periapical repair of teeth with periapical lesion following root canal treatment by using a calcium hydroxide-based intracanal dressing for several time periods or filling in a single visit.

Title Prostate Response to Prolactin in Sexually Active Male Rats.
Date September 2006
Journal Reproductive Biology and Endocrinology : Rb&e
Excerpt

BACKGROUND: The prostate is a key gland in the sexual physiology of male mammals. Its sensitivity to steroid hormones is widely known, but its response to prolactin is still poorly known. Previous studies have shown a correlation between sexual behaviour, prolactin release and prostate physiology. Thus, here we used the sexual behaviour of male rats as a model for studying this correlation. Hence, we developed experimental paradigms to determine the influence of prolactin on sexual behaviour and prostate organization of male rats. METHODS: In addition to sexual behaviour recordings, we developed the ELISA procedure to quantify the serum level of prolactin, and the hematoxilin-eosin technique for analysis of the histological organization of the prostate. Also, different experimental manipulations were carried out; they included pituitary grafts, and haloperidol and ovine prolactin treatments. Data were analyzed with a One way ANOVA followed by post hoc Dunnet test if required. RESULTS: Data showed that male prolactin has a basal level with two peaks at the light-dark-light transitions. Consecutive ejaculations increased serum prolactin after the first ejaculation, which reached the highest level after the second, and started to decrease after the third ejaculation. These normal levels of prolactin did not induce any change at the prostate tissue. However, treatments for constant elevations of serum prolactin decreased sexual potency and increased the weight of the gland, the alveoli area and the epithelial cell height. Treatments for transient elevation of serum prolactin did not affect the sexual behaviour of males, but triggered these significant effects mainly at the ventral prostate. CONCLUSION: The prostate is a sexual gland that responds to prolactin. Mating-induced prolactin release is required during sexual encounters to activate the epithelial cells in the gland. Here we saw a precise mechanism controlling the release of prolactin during ejaculations that avoid the detrimental effects produced by constant levels. However, we showed that minor elevations of prolactin which do not affect the sexual behaviour of males, produced significant changes at the prostate epithelium that could account for triggering the development of hyperplasia or cancer. Thus, it is suggested that minute elevations of serum prolactin in healthy subjects are at the etiology of prostate abnormal growth.

Title Trunk Repositioning Errors Are Increased in Balance-impaired Older Adults.
Date January 2006
Journal The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
Excerpt

BACKGROUND: Controlling the flexing trunk is critical in recovering from a loss of balance and avoiding a fall. To investigate the relationship between trunk control and balance in older adults, we measured trunk repositioning accuracy in young and balance-impaired and unimpaired older adults. METHODS: Young adults (N = 8, mean age 24.3 years) and two groups of community-dwelling older adults defined by unipedal stance time (UST)-a balance-unimpaired group (UST > 30 seconds, N = 7, mean age 73.9 years) and a balance-impaired group (UST < 5 seconds, N = 8, mean age 79.6 years)-were tested in standing trunk control ability by reproducing a approximately 30 degrees trunk flexion angle under three visual-surface conditions: eyes opened and closed on the floor, and eyes opened on foam. Errors in reproducing the angle were defined as trunk repositioning errors (TREs). Clinical measures related to balance, trunk extensor strength, and self-reported disability were obtained. RESULTS: TREs were significantly greater in the balance-impaired group than in the other groups, even when controlling for trunk extensor strength and body mass. In older adults, there were significant correlations between TREs and three clinical measures of balance and fall risk, UST and maximum step length (-0.65 to -0.75), and Timed Up & Go score (0.55), and between TREs and age (0.63-0.76). In each group TREs were similar under the three visual-surface conditions. Test-retest reliability for TREs was good to excellent (intraclass correlation coefficients > or =0.74). CONCLUSIONS: Older balance-impaired adults have larger TREs, and thus poorer trunk control, than do balance-unimpaired older individuals. TREs are reliable and valid measures of underlying balance impairment in older adults, and may eventually prove to be useful in predicting the ability to recover from losses of balance and to avoid falls.

Title Shewanella Oneidensis Mr-1 Uses Overlapping Pathways for Iron Reduction at a Distance and by Direct Contact Under Conditions Relevant for Biofilms.
Date October 2005
Journal Applied and Environmental Microbiology
Excerpt

We developed a new method to measure iron reduction at a distance based on depositing Fe(III) (hydr)oxide within nanoporous glass beads. In this "Fe-bead" system, Shewanella oneidensis reduces at least 86.5% of the iron in the absence of direct contact. Biofilm formation accompanies Fe-bead reduction and is observable both macro- and microscopically. Fe-bead reduction is catalyzed by live cells adapted to anaerobic conditions, and maximal reduction rates require sustained protein synthesis. The amount of reactive ferric iron in the Fe-bead system is available in excess such that the rate of Fe-bead reduction is directly proportional to cell density; i.e., it is diffusion limited. Addition of either lysates prepared from anaerobic cells or exogenous electron shuttles stimulates Fe-bead reduction by S. oneidensis, but iron chelators or additional Fe(II) do not. Neither dissolved Fe(III) nor electron shuttling activity was detected in culture supernatants, implying that the mediator is retained within the biofilm matrix. Strains with mutations in omcB or mtrB show about 50% of the wild-type levels of reduction, while a cymA mutant shows less than 20% of the wild-type levels of reduction and a menF mutant shows insignificant reduction. The Fe-bead reduction defect of the menF mutant can be restored by addition of menaquinone, but menaquinone itself cannot stimulate Fe-bead reduction. Because the menF gene encodes the first committed step of menaquinone biosynthesis, no intermediates of the menaquinone biosynthetic pathway are used as diffusible mediators by this organism to promote iron reduction at a distance. CymA and menaquinone are required for both direct and indirect mineral reduction, whereas MtrB and OmcB contribute to but are not absolutely required for iron reduction at a distance.

Title Timing Between Ejaculations Changes Paternity Success.
Date July 2004
Journal Physiology & Behavior
Excerpt

It is believed that when two male rats copulate with a single female, the last one that ejaculates fathers significantly more pups than the first one. To determine the effects of order and elapsed time between two males copulating with the same female, albino Wistar (W) and pigmented Long-Evans (LE) male rats copulated with a W female. Paternity was confirmed by the pups' pigmentation. Three groups were made according to the elapsed time between the first male's ejaculation and the placement of the female with the second male; T0 (0-min group); T5 (5-min group); and T10 (10-min group). Male order was counterbalanced in each group. The results showed that the second male had the advantage in T0, but the first males had the advantage in T5 and T10. These data indicate that in a two-male situation, the advantage in paternity for a second male occurs only during copulations following the first few minutes of a first male's ejaculation. After 5 min, a second male has no advantage in fathering pups.

Title Phenazines and Other Redox-active Antibiotics Promote Microbial Mineral Reduction.
Date June 2004
Journal Applied and Environmental Microbiology
Excerpt

Natural products with important therapeutic properties are known to be produced by a variety of soil bacteria, yet the ecological function of these compounds is not well understood. Here we show that phenazines and other redox-active antibiotics can promote microbial mineral reduction. Pseudomonas chlororaphis PCL1391, a root isolate that produces phenazine-1-carboxamide (PCN), is able to reductively dissolve poorly crystalline iron and manganese oxides, whereas a strain carrying a mutation in one of the phenazine-biosynthetic genes (phzB) is not; the addition of purified PCN restores this ability to the mutant strain. The small amount of PCN produced relative to the large amount of ferric iron reduced in cultures of P. chlororaphis implies that PCN is recycled multiple times; moreover, poorly crystalline iron (hydr)oxide can be reduced abiotically by reduced PCN. This ability suggests that PCN functions as an electron shuttle rather than an iron chelator, a finding that is consistent with the observation that dissolved ferric iron is undetectable in culture fluids. Multiple phenazines and the glycopeptidic antibiotic bleomycin can also stimulate mineral reduction by the dissimilatory iron-reducing bacterium Shewanella oneidensis MR1. Because diverse bacterial strains that cannot grow on iron can reduce phenazines, and because thermodynamic calculations suggest that phenazines have lower redox potentials than those of poorly crystalline iron (hydr)oxides in a range of relevant environmental pH (5 to 9), we suggest that natural products like phenazines may promote microbial mineral reduction in the environment.

Title Acute Onset of Wegener's Granulomatosis and Diffuse Alveolar Hemorrhage Treated Successfully by Extracorporeal Membrane Oxygenation.
Date October 2003
Journal Pediatric Critical Care Medicine : a Journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies
Excerpt

Wegener's granulomatosis is a necrotizing granulomatous vasculitis involving the upper airway, lungs, and kidneys. Diffuse alveolar hemorrhage is a rare and life-threatening presentation of Wegener's granulomatosis. We report on a previously healthy 13-yr-old boy who presented with fulminant pulmonary hemorrhage leading to acute respiratory distress syndrome and was found to have Wegener's granulomatosis. The diagnosis was based on clinical, radiologic, serologic, and histologic manifestations. The therapeutic challenges and the modalities of support to sustain life until clinical remission are presented.

Title Neuroendocrine Control of Urine-marking Behavior in Male Rats.
Date June 2002
Journal Physiology & Behavior
Excerpt

Sexually experienced Wistar male rats were used to investigate (a) urine voiding in the presence of nearby estrous females and the control of such voiding by (b) steroid hormones and (c) peripheral nerves supplying the genitourinary system. The first experiment showed that males always have a low rate of urine voiding that is significantly increased when a receptive female is around. Thus, it is suggested that an airborne scent from the female stimulates the olfactory system of males, triggering urine emission to transmit sex-related messages, i.e., male rats display the well-known urine-marking behavior of mammals. The number of urine marks and sniffing to females decreased after castration, and were restored after exogenous treatment with testosterone or estradiol. The proposed hypothesis is that airborne scents from the female activate the aromatization process in nuclei of the olfactory pathway of the male, evoking a cascade of neuronal responses that finish in urine marking. Peripheral nerves supplying the genitourinary system are the viscerocutaneous branch of the pelvic nerve (Vc) and the hypogastric (Hg). Data showed that both nerves are important for the central control of urine storage and voiding. Transection of Vc almost blocked urine marking, while Hg lesion increased the number of marks. Thus, it is discussed that Vc is the most important nerve in charge of voiding the bladder, and that Hg is important for continence.

Title Linear Dimensions of the Upper Airway Structure During Development: Assessment by Magnetic Resonance Imaging.
Date February 2002
Journal American Journal of Respiratory and Critical Care Medicine
Excerpt

The upper airway undergoes progressive changes during childhood. Using magnetic resonance imaging (MRI), we studied the growth relationships of the tissues surrounding the upper airway (bone and soft tissues) in 92 normal children (47% males; range, 1 to 11 yr) who underwent brain MRI. None had symptoms of sleep-disordered breathing or conditions that impacted on their upper airway. MRI was performed under sedation. Sequential T1-weighted spin echo sagittal and axial sections were obtained and analyzed on a computer. We measured lower face skeletal growth along the midsagittal and axial oropharyngeal planes. In the midsagittal plane the mental spine-clivus distance related linearly to age (r = 0.86, p < 0.001). Along this axis, the dimensions of tongue, soft palate, nasopharyngeal airway, and adenoid increased with age and maintained constant proportion to the mental spine-clivus distance. Similarly, a linear relationship was noted for mandibular growth measured along the intermandibular line on the axial plane and age (r = 0.78, p < 0.001). In addition, the intertonsillar, tonsils, parapharyngeal fat pads, and pterygoids widths maintained constant proportion to intermandibular width with age. We conclude that the lower face skeleton grows linearly along the sagittal and axial planes from the first to the eleventh year. Our data indicate that soft tissues, including tonsils and adenoid, surrounding the upper airway grow proportionally to the skeletal structures during the same time period.

Title Extracellular Electron Transfer.
Date December 2001
Journal Cellular and Molecular Life Sciences : Cmls
Excerpt

Results from several laboratories indicate that extracellular electron transfer may be a general mechanism whereby microoorganisms generate energy for cell growth and/or maintenance. Specifically, bacteria can use redox-active organic small molecules, generated outside or inside the cells, to shuttle electrons between reduced and oxidized compounds. Electron shuttling has now been reported for several different bacterial species, and exchanges of shuttling compounds may even syntrophically link diverse organisms in nature. Biofilm systems in both geological and clinical settings are likely to be important environments for metabolisms that employ extracellular electron transfer. Both structural and functional analyses suggest that electron shuttles and some virulence factors may be related to one another.

Title Fertility Ratio in Male Rats: Effects After Denervation of Two Pelvic Floor Muscles.
Date May 2000
Journal Physiology & Behavior
Excerpt

Fertility ratio is defined here as the proportion of females that a male can impregnate after a constant period of in-polygyny living. This ratio was investigated in male rats after denervation of two pelvic floor muscles, the pubococcygeus and iliococcygeus. Denervation was carried out by transecting the somatomotor branch of the pelvic nerve. The lesion did not modify the sexual behavior of males or their overall fertility, but decreased the weight of the ejaculated seminal plug. Consequently, the number of days living in cohabitation to induce pregnancy was increased in lesioned males (approximately 13 days) compared with intact and sham animals (approximately 5 days). These results showed that the fertility ratio was optimal when intact/sham males cohabited with females for two consecutive estrous cycles, but that lesioned males needed up to four cycles to induce most pregnancies. Two hypotheses are raised by our results. The first is that pelvic floor denervation decreases the forceful tension required to expel the semen from the prostatic urethra to the vagina, then an incomplete seminal plug is expelled. The second is that denervation cut afferent fibers that reflexively promote the continence of the semen deposited in the prostatic urethra during seminal emission, allowing some to leak out before ejaculation. The latter hypothesis can also explain the recovery of the fertility ratio in lesioned males. It could be a compensatory mechanism mediated by the pudendal nerve supply to the coccygeus muscle, the other pelvic floor muscle.

Title Spinal Organization and Steroid Sensitivity of Motoneurons Innervating the Pubococcygeus Muscle in the Male Rat.
Date July 1999
Journal The Journal of Comparative Neurology
Excerpt

Male rat motoneurons innervating the pubococcygeus muscle were located in the ventral nucleus of lamina IX at the sixth lumbar (L6) and first sacral (S1) spinal cord segments. Retrograde labeling with horseradish peroxidase-wheat germ agglutinin was transported up to second-order dendrites and revealed that these motoneurons have a "U-shaped arborization" of dendrites toward the intermediolateral and intermediomedial nuclei area of lamina VII. This dendritic organization makes a wide "final common path" that probably integrates afferent information from several sources, accounting for the participation of the pubococcygeus muscle in autonomic and somatic processes, such as those related to micturition and reproduction. Castration produced a decrement in the morphometry of these motoneurons. A main effect was a decrement in dendritic length. Steroid replacement indicated that testosterone and estradiol, but not dihydrotestosterone, are able to induce a recovery of morphometric alterations. However, estrogen induced recovery after 2 weeks of treatment, whereas testosterone took 4 weeks. Thus, it is proposed that supraspinal aromatization of testosterone in the male central nervous system might be an important process for the appropriate organization of the pubococcygeus muscle motoneurons and that estradiol seems to need a shorter time of action than testosterone because of differential up-regulation and down-regulation of steroid receptors.

Title Surgically-assisted Diagnostic Laparoscopy.
Date May 1995
Journal The American Journal of Gastroenterology
Title Laparoscope Examination Without Pneumoperitoneum for Lysis of Adhesions Before Laparoscopic-guided Liver Biopsy.
Date July 1994
Journal Gastrointestinal Endoscopy
Title Endoscopic Therapy of Gastroplasty Outlet Obstruction.
Date May 1994
Journal Gastrointestinal Endoscopy
Title Endoscopic Polypectomy of a Large Duodenal Carcinoid.
Date February 1994
Journal Gastrointestinal Endoscopy
Title The Endoscopic Diagnosis of the Invaginating Ampulla of Vater Mimicking Choledocholithiasis.
Date January 1994
Journal The American Journal of Gastroenterology
Title Risk of Needle-stick Injuries in the Transmission of Hepatitis C Virus in Hospital Personnel.
Date February 1993
Journal Journal of Hepatology
Excerpt

To assess the risk to hospital personnel of acquiring an hepatitis C virus (HCV) infection as a result of occupational exposure to needle-stick injuries, 81 employees who had parenteral exposure to an anti-HCV-positive source were followed for 12 months. None developed hepatitis and anti-HCV testing by a second-generation ELISA system of serum samples collected on the day of exposure and at 3, 6 and 12 months was negative. Consequently, a low efficacy of needle-stick injuries in the transmission of HCV in hospital personnel may be suggested.

Title Combined Injection and Thermal Therapy in the Management of Early Post-polypectomy Bleeding.
Date November 1992
Journal The American Journal of Gastroenterology
Title Endoscopic Examination of the Common Hepatic Duct and Cholangiography in a Patient with Previous Roux-en-y Hepaticojejunostomy and Billroth I Operation.
Date November 1992
Journal Gastrointestinal Endoscopy
Title Endoscopic Removal of an Impacted Colonic Foreign Body (fish Bone) Complicated by a Pelvic Abscess.
Date July 1992
Journal Gastrointestinal Endoscopy
Title Endoscopic Treatment of the Sump Syndrome Without Sphincterotomy.
Date April 1991
Journal Gastrointestinal Endoscopy
Title Fulminant Liver Failure and Pancreatitis Associated with the Use of Sulfamethoxazole-trimethoprim.
Date January 1990
Journal The American Journal of Gastroenterology
Excerpt

We report the case of a 26-yr-old patient with fulminant liver failure and acute hemorrhagic pancreatitis secondary to the use of trimethoprim-sulfamethoxazole (Bactrim DS). Our patient presented with skin rash and decreased C3 and C4 levels, which we believed was due to a hypersensitivity reaction secondary to the sulfonamide component (sulfamethoxazole). To our knowledge, this is the first case reported in which sulfamethoxazole-trimethoprim has been implicated as a cause of fulminant liver failure and acute hemorrhagic pancreatitis simultaneously, and emphasizes the need of discontinuing this medication as soon as there is evidence of liver and pancreatic dysfunction.

Title Fulminant Idiopathic Pseudomembranous Colitis.
Date September 1989
Journal American Family Physician
Excerpt

Pseudomembranous colitis is characterized by inflammatory plaques and pseudomembranes on the colonic mucosa. The disorder most commonly occurs after the use of antibiotics, which allow overgrowth of Clostridium difficile, a spore-forming, gram-positive rod that produces a toxin. Overgrowth of Staphylococcus aureus can also produce pseudomembranous colitis. In rare cases, pseudomembranous colitis is not associated with antibiotic use. When C. difficile is present, vancomycin or metronidazole usually produces a prompt response. In idiopathic cases, surgery may be required.

Title Endoscopic Removal of a Large Common Bile Duct Stone Through a Choledochoduodenostomy.
Date October 1988
Journal Gastrointestinal Endoscopy
Title Gastric "tattooing": a Technique for Anatomic Localization of Small Bleeding Lesions.
Date September 1986
Journal The American Journal of Gastroenterology
Title Pyogenic Liver Abscess.
Date December 1983
Journal American Family Physician
Excerpt

The primary source of pyogenic liver abscess is undetermined in about 30 percent of cases. Escherichia coli, microaerophilic streptococci and Bacteroides fragilis are among the common pathogens. Some cases can be treated with antibiotics alone; others require surgical management. With improved methods of diagnosis and therapy, the mortality rate is now 10 percent or less.

Title Proinflammatory Cytokine Levels in Fibromyalgia Patients Are Independent of Body Mass Index.
Date
Journal Bmc Research Notes
Excerpt

ABSTRACT:


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