Urologists
30 years of experience
Video profile
Accepting new patients
Chestnut Hill
8815 Germantown Ave
Ste 34
Philadelphia, PA 19118
215-247-3082
Locations and availability (1)

Education ?

Medical School Score Rankings
University of Pennsylvania (1980)
  • Currently 4 of 4 apples
Top 25%

Awards & Distinctions ?

Associations
American Urological Association
American Board of Urology

Affiliations ?

Dr. Garber is affiliated with 16 hospitals.

Hospital Affilations

Score

Rankings

  • Chestnut Hill Hospital
    8835 Germantown Ave, Philadelphia, PA 19118
    • Currently 4 of 4 crosses
    Top 25%
  • Thomas Jefferson University Hospital
    Urology
    111 S 11th St, Philadelphia, PA 19107
    • Currently 4 of 4 crosses
    Top 25%
  • Methodist Hospital
    Urology
    2301 S Broad St, Philadelphia, PA 19148
    • Currently 3 of 4 crosses
    Top 50%
  • Nazareth Hospital
    2601 Holme Ave, Philadelphia, PA 19152
    • Currently 3 of 4 crosses
    Top 50%
  • Mercy Hospital of Philadelphia
    1503 Lansdowne Ave, Darby, PA 19023
    • Currently 3 of 4 crosses
    Top 50%
  • University of PA Medical Center/Presbyterian
    Urology
    51 N 39th St, Philadelphia, PA 19104
    • Currently 3 of 4 crosses
    Top 50%
  • Taylor Hospital - Crozer Chester
    175 E Chester Pike, Ridley Park, PA 19078
    • Currently 2 of 4 crosses
  • Mercy Fitzgerald Hospital
    1400 Lansdowne Ave, Darby, PA 19023
    • Currently 2 of 4 crosses
  • Hahnemann University Hospital
    230 N Broad St, Philadelphia, PA 19102
    • Currently 2 of 4 crosses
  • Delaware County Memorial Hospital
    501 N Lansdowne Ave, Drexel Hill, PA 19026
    • Currently 2 of 4 crosses
  • Mercy Suburban Hospital
    2701 Dekalb Pike, Norristown, PA 19401
    • Currently 2 of 4 crosses
  • Crozer-Chester Medical Center
    1 Medical Center Blvd, Chester, PA 19013
    • Currently 2 of 4 crosses
  • Graduate Hospital
    1800 Lombard St, Philadelphia, PA 19146
    • Currently 1 of 4 crosses
  • Mercy Philadelphia Hospital
  • Presbyterian Medical Center Of The University Of Pennsylvania Health System
  • HttpWww.Mercyhealth.OrgFitzgerald
  • Publications & Research

    Dr. Garber has contributed to 30 publications.
    Title Coloplast Titan Inflatable Penile Prosthesis with One-touch Release Pump: Review of 100 Cases and Comparison with Genesis Pump.
    Date May 2011
    Journal The Journal of Sexual Medicine
    Excerpt

    In 2008 Coloplast Corporation modified their Titan inflatable penile prosthesis (IPP) with a new One-Touch Release (OTR) pump, in an attempt to facilitate device deflation. There is currently little published data concerning this new pump.

    Title Inflatable Penile Prostheses for the Treatment of Erectile Dysfunction: an Update.
    Date August 2008
    Journal Expert Review of Medical Devices
    Excerpt

    Male erectile dysfunction (ED) is a common medical condition. Three oral medications (sildenafil, vardenafil and tadalafil, all phosphodiesterase type 5 inhibitors) have been developed and approved for the treatment of ED by the US FDA. Extensive worldwide marketing of these medications has raised public awareness of ED, and allowed many previously untreated men to seek and receive effective therapy. A variety of other ED treatments are available and approved by the FDA, including vacuum-constriction devices and intracavernous or intraurethral alprostadil. However, roughly 30-40% of men with ED are not adequately served by these treatments due to their cost, side effects, contraindications, the need to 'time' sexual activity, or lack of satisfactory erectile response. For men who do not respond to less invasive therapy, an inflatable penile prosthesis can provide a satisfying and effective alternative. This article will review and critique the inflatable penile prostheses that are currently available in the USA and the EU for the treatment of ED.

    Title Inflatable Penile Prosthesis: Site-specific Malfunction Analysis.
    Date September 2003
    Journal International Journal of Impotence Research
    Excerpt

    The purpose of this study was to analyze retrospectively the exact site(s) of device failure of a large series of Mentor Alpha I inflatable penile prostheses. The study consisted of 442 patients implanted over a 12-year period. Only those patients who developed a device malfunction and returned for re-evaluation by the author were included. The exact site(s) of device malfunction were obtained from a review of operative reports. The average length of follow-up in this series was 63 months, ranging from 1 to 138 months. In all, 22 (4.98%) patients developed device malfunction and returned for evaluation, including six (3.9%) of the 154 infrapubic devices and 16 (5.6%) of the 288 scrotal devices. Of these 22 patients, three declined revision and 19 were reoperated on by the author. The exact site of malfunction differed in the infrapubic vs scrotal implants. Most malfunctions of the scrotal device involved tubing fractures at the pump strain reliefs, whereas infrapubic device malfunctions typically involved the cylinders or the reservoir. A review of these malfunction patterns may assist the manufacturer in further improving the reliability of this prosthesis, and may assist implanting surgeons in planning operative procedures.

    Title Does Surgical Approach Affect the Incidence of Inflatable Penile Prosthesis Infection?
    Date August 1998
    Journal Urology
    Excerpt

    OBJECTIVES: To review retrospectively the rate of infection in 380 consecutive organically impotent men implanted with a Mentor Alpha I inflatable penile prosthesis, stratified by surgical approach (scrotal or infrapubic). METHODS: Data were obtained from review of medical records. One hundred percent of cases were available for a minimum postoperative follow-up of 6 months. RESULTS: Twenty patients had a prior penile prosthetic operation and were excluded, leaving 360 primary implants for review. Overall, 6 patients (1.7%) developed periprosthetic infection. Four of these 6 patients were diabetic. Four of 139 infrapubic cases (2.9%) and 2 of 221 scrotal cases (0.9%) developed periprosthetic infection. This difference was not statistically significant (P = 0.15). Equal proportions of the infrapubic (39.6%) and scrotal cases (40.3%) were diabetic patients. The infection rate in patients with and without diabetes was 4 of 144 (2.8%) and 2 of 216 (0.9%), respectively. This difference was not statistically significant (P = 0.18). CONCLUSIONS: This study indicates that there is no statistically significant difference in the infection rate when the scrotal and infrapubic approaches to inflatable penile prosthesis insertion are compared.

    Title Outpatient Inflatable Penile Prosthesis Insertion.
    Date May 1997
    Journal Urology
    Excerpt

    OBJECTIVES: To assess the initial results of an ambulatory, outpatient, multiple-component inflatable penile prosthesis (IPP) insertion protocol. METHODS: Ninety-five consecutive men with organic impotence were implanted with a multiple-component IPP on an outpatient basis. Short-term complications were assessed by direct patient examination, phone interview, and office visits. RESULTS: Complications seen with this approach included 1 patient who required hospitalization for gross hematuria, 1 patient with a periprosthetic infection, and 4 patients who were unable to void and were sent home with a urethral catheter. CONCLUSIONS: Multiple-component IPP insertion is easily adaptable to the outpatient setting. The prosthetic infection rate (1%) was similar to that seen with inpatient implantation protocols. Urinary retention (4%) was the most frequent complication, and it was easily managed with temporary catheterization. Early results suggest that outpatient IPP insertion is a safe, effective treatment for men with organic impotence.

    Title Intracorporal Lengths of Organically Impotent Men.
    Date March 1997
    Journal International Journal of Impotence Research
    Excerpt

    This report analyzes the intracorporal lengths of 236 consecutive organically impotent men who underwent insertion of a penile prosthesis. The average right or left intracorporal length in this series was 20.9 cm, with a standard deviation of 2.2 cm. Intracorporal length ranged from 14-27 cm. This data may be used as reference ranges for penile prosthesis manufacturers, and for Urologists who implant prostheses or perform penile lengthening procedures.

    Title Inflatable Penile Prosthesis: Results of 150 Cases.
    Date February 1997
    Journal British Journal of Urology
    Excerpt

    OBJECTIVES: To evaluate the reliability of the prosthesis and the rate of complications in organically impotent men who were implanted with an inflatable penile prosthesis. PATIENTS AND METHODS: A consecutive series of 150 men (mean age 60 years, range 25-90) were followed for a mean of 19 months (range 0-65) after implantation of the Mentor Alpha 1 penile prosthesis. Information was obtained from their medical records and by telephone interview, but the satisfaction of the patients was not assessed quantitatively. RESULTS: There were no complications in 145 of the patients and they currently have functioning prostheses. Complications occurred in five patients (3%), including two peri-prosthetic infections (1%) and two intra-operative and one post-operative cylinder aneurysm. Complications requiring re-operation occurred in three (2%) of patients; none of the implants leaked. CONCLUSIONS: These results suggest that for men with organic impotence, a Mentor Alpha 1 implant is an effective treatment option with acceptable morbidity and good mechanical reliability.

    Title Retraction Method for Implantation of Penile Prosthesis.
    Date November 1995
    Journal British Journal of Urology
    Title Mentor Alpha-1 Inflatable Penile Prosthesis Cylinder Aneurysm: an Unusual Complication.
    Date October 1995
    Journal International Journal of Impotence Research
    Excerpt

    This report describes the author's experience with Mentor Alpha-1 inflatable penile prosthesis cylinder aneurysms. In a series of 93 consecutive cases three implants developed a cylinder aneurysm. Two aneurysms developed intraoperatively and one developed 27 months postoperatively. Literature review suggests that the Mentor Alpha-1 penile prosthesis cylinders are very resistant to aneurysm formation under normal circumstances. However aneurysmal dilatation may occur if the cylinders are subjected to unusual stress.

    Title Mentor Alpha 1 Inflatable Penile Prosthesis: Patient Satisfaction and Device Reliability.
    Date March 1994
    Journal Urology
    Excerpt

    OBJECTIVE. This report describes a study of patient satisfaction and device reliability in 50 organically impotent males who were implanted with a Mentor Alpha 1 inflatable penile prosthesis. METHOD. Data were obtained from review of medical records, and patient-completed structured questionnaires. RESULTS. The average patient age was fifty-nine years (range: 25 to 90 years). Thirty-one patients (62%) had underlying medical conditions, and all tried at least one other treatment prior to implantation. All patients received perioperative prophylactic antibiotics, and all were drained with a closed suction drain for twenty-four hours. Follow-up ranged from two to forty-one months (av. 15 mos). Complications occurred in 2 patients (4%), including 1 periprosthetic infection and 1 intraoperative cylinder aneurysm. An average of one office visit was required for teaching inflation/deflation. Ninety-eight percent of the patients and 96 percent of their partners were satisfied with the device. Ninety-four percent and 96 percent thought the device was easy to inflate and deflate, respectively. Two patients (4%) reported partial cylinder inflation related to physical activity. All were satisfied with the girth and rigidity, but only 92 percent were satisfied with the length. Ninety-eight percent said they would undergo the procedure again and would recommend this implant to other impotent patients. CONCLUSIONS. These data indicate that the Mentor Alpha 1 device has good short-term mechanical reliability, and yields a high level of patient and partner satisfaction.

    Title Masson's Tumor of the Kidney: a New Renal Lesion.
    Date February 1990
    Journal The Journal of Urology
    Excerpt

    Intravascular papillary endothelial hyperplasia (Masson's tumor) is a rare benign reactive lesion usually found in thrombosed subcutaneous blood vessels. We report a case of Masson's tumor of the kidney, and discuss the relevant clinical, radiographical and pathological aspects.

    Title Xanthogranulomatous Pyelonephritis and Amyloidosis: a Rare Association.
    Date July 1989
    Journal The Journal of Urology
    Excerpt

    The coincidence of systemic amyloidosis and xanthogranulomatous pyelonephritis has been reported previously only once. Clinical findings, such as the nephrotic syndrome, cardiac and autonomic nervous system dysfunction, and adrenal insufficiency, are suggestive and a thorough investigation to rule out other causes of secondary amyloidosis is warranted. We report a case of xanthogranulomatous pyelonephritis associated with secondary systemic amyloidosis and the nephrotic syndrome. Treatment consisted of nephrectomy and intensive supportive care. The unique clinical, radiographic and pathological aspects of this case are discussed.

    Title Effect of Contractile Activity on Muscarinic Receptor Density and the Response to Muscarinic Agonists.
    Date December 1988
    Journal The Journal of Pharmacology and Experimental Therapeutics
    Excerpt

    Autonomic receptor density can be modulated by alterations in neuronal activity over a relatively short period of time (hours). The current study investigates whether increased in vivo stimulation of urinary bladder smooth muscle can alter muscarinic receptor density and response to muscarinic stimulation. A high degree of reflex stimulation of the urinary bladder (rabbits) was initiated by stricture of the external urethra. Intravesical pressure and intra-abdominal pressure were monitored continuously over a 4-hr time period. At the end of the 4-hr period, the rabbits were sacrificed and isolated strips of bladder body were either mounted in isolated smooth muscle baths for contractile studies or frozen and stored in liquid nitrogen for muscarinic receptor analysis. These studies demonstrated that over 4 hr of urethral stricture there was a significant reduction in muscarinic receptor density from a Bmax of 34 +/- 3.4 fmol/mg of protein in control bladder strips to 22 +/- 2.4 fmol/mg of protein in the experimental group. In association with the decreased muscarinic receptor density, there was a significant and selective decrease in the contractile response to muscarinic stimulation. Similar to the in vivo studies, repetitive field stimulation of in vitro strips resulted in a significant decrease in muscarinic receptor density and a significant and selective decrease in the contractile response to muscarinic stimulation. The results from these studies indicate that muscarinic receptor density, and response to muscarinic stimulation, can be modulated over a relatively short period of time by alterations in the level of neuronal stimulation.

    Title Characterization of a Salmonella Typhimurium Mutant Defective in Phosphoribosylpyrophosphate Synthetase.
    Date April 1985
    Journal Journal of General Microbiology
    Excerpt

    This study describes the isolation and characterization of a mutant (strain GP122) of Salmonella typhimurium with a partial deficiency of phosphoribosylpyrophosphate (PRPP) synthetase activity. This strain was isolated in a purE deoD gpt purin auxotroph by a procedure designed to select guanosine-utilizing mutants. Strain GP122 had roughly 15% of the PRPP synthetase activity and 25% of the PRPP pool of its parent strain. The mutant exhibited many of the predicted consequences of a decreased PRPP pool and a defective PRPP synthetase enzyme, including: poor growth on purine bases; decreased accumulation of 5-aminoimidazole ribonucleotide (the substrate of the blocked purE reaction) under conditions of purine starvation; excretion of anthranilic acid when grown in medium lacking tryptophan; increased resistance to inhibition by 5-fluorouracil; derepressed levels of aspartate transcarbamylase and orotate phosphoribosyltransferase, enzymes involved in the pyrimidine de novo biosynthetic pathway; growth stimulation by PRPP-sparing compounds (e.g. guanosine, histidine); poor growth in low phosphate medium; and increased heat lability of the defective enzyme. This mutant strain also had increased levels of guanosine 5'-monophosphate reductase. This genetic lesion, designated prs, was mapped by conjugation and phage P22-mediated transduction at 35 units on the Salmonella linkage map.

    Title Immunochemical Analysis of Fibronectin Using Monoclonal Antibodies.
    Date December 1982
    Journal Biochimica Et Biophysica Acta
    Excerpt

    Cloned hybrid cell lines secreting antibodies directed against human plasma fibronectin were prepared according to the methods of Kohler and Milstein (Kohler, G. and Milstein, C. (1975) Nature (London) 256, 495-497 and (1976) Eur. J. Immunol. 6, 511-519). The specificity of each monoclonal antibody for fibronectin was established from autoradiograms of radioimmunoprecipitates following SDS-polyacrylamide gel electrophoresis. The monoclonal antibodies were reactive with both native and SDS-denatured fibronectin. Ascites fluids obtained from infected isogenic mice precipitated 85-95% of the 125I-labelled fibronectin radioactivity in indirect radioimmunoprecipitation tests. Localization of specific epitopes to restricted regions of the fibronectin molecule was carried out by monitoring monoclonal antibody binding to proteolytic fragments. Of the five monoclonal antibodies analyzed in this study, three recognized determinants which resided in the terminal 35 kDa region of the fibronectin monomer. Furthermore, these epitopes were localized to fragments as small as 20 kDa. Competition studies carried out using plasma fibronectins isolated from different species revealed that three monoclonal antibodies recognized sites which were relatively conserved, while two monoclonal antibodies recognized epitopic sequences which were unique to the human protein. The corresponding anti-fibronectin serum also demonstrated discriminatory capabilities. Immunofluorescent analysis of human fibroblasts grown in vitro demonstrated that all the monoclonal antibodies tested were reactive with pericellular fibronectin.

    Title Separation and Characterization of Neuronal and Glial Cell Populations from Embryonic Chick Cerebra in Culture.
    Date August 1982
    Journal Anatomischer Anzeiger
    Excerpt

    A new procedure of separation of glial and neuronal cell population from embryonic chick cerebra has been described and their morphology in vitro was examined by SEM. This technique used the differential adhesive properties of the glial and neuronal cells to obtain an initial separation in primary monolayer culture. The neuronal fraction was then further purified by treatment with cytosine arabinoside. The homogeneity of the glial and neuronal cultures produced by this technique was examined by phase contrast and scanning electron microscopy, liquid scintillation counting of incorporation of radioactive precursors into the cultured cells and autoradiographic study of the cultures. The purity of the neuronal culture was estimated to be better than 97 and 98% based on LSC and autoradiography respectively. The purity of glial culture was assessed by phase contrast and SEM and was estimated to have a purity of over 99%. The viability of the both cultures was good following initial separation. The glial cells were typically epitheloid and formed confluent monolayer 7--10 days after initial separation. These cells have a smooth upper surface and are typically hexagonal in shape. The neuronal cultures formed small aggregates interconnected with compound neuronal processes. It was noted that the neuronal differentiation was closely related to the glial cells. In the presence of a glial carpet, the aggregates became flattened and well differentiated neuronal cells were found. On the contrary, round neuronal aggregates were found. In the case of mixed cultures of glial and neuronal cells neurites were seen grown mainly on the surface of glial carpet. Only in rare occasions, neurites were seen bridging over the bare glass surface.

    Title Scanning Electron Microscopic Observations on the Interaction Between Normal Neuronal and Tumour Cells in Monolayer Culture.
    Date January 1982
    Journal Anatomischer Anzeiger
    Excerpt

    Interaction of embryonic chick cerebral cells with the astrocytoma (C6) and neuroblastoma (N2a) cells were examined by SEM. When astrocytoma cells were added to the glial monolayer cell substratum the glial substratum was loosened and astrocytoma cells grew into the gaps of the loosened glial substratum. It is believed that the penetrating property of the astrocytoma cells may be related to the invasiveness of the tumour cells. When neuroblastoma (N2a) cells were added to normal glial substratum, no invasion of the glial substratum was observed. Instead, for the first 2 days the tumour cells rested on the glial substratum and sent out numerous fine filopodia (0.1-0.2 micrometers) closely adhered to the surface of the glial cells. On the third day, the groups of glial cells underneath the neuroblastoma cells, which have been covered by filopodia of the tumour cells were rounded and became retracted from the glial substratum. These morphologically altered cells showed features of the tumour cells. It is therefore speculated that neuroblastoma cells have the ability of changing (transforming?) the glial cells probably through their filopodia. When neuroblastoma cells were added to the astrocytoma substratum, there was an initial reaction on both cell types in which lamellipodia were extremely developed. This initial reaction subsided about 24 hours later and the neuroblastoma cells became more flattened, and grew on the astrocytoma substratum. In this case no rounding up of astrocytoma cells was observed. Normal neuronal cells when added to astrocytoma substratum, showed well differentiated neuronal characteristics. This indicates that neuronal differentiation can be maintained by a tumour substratum.

    Title Selective Association of Embryonic Murine Mesencephalic Dopamine Neurons in Vitro.
    Date December 1981
    Journal Brain Research
    Title 3h-thymidine Autoradiographic Analysis of Telencephalic Histogenesis in the Chick Embryo: I. Neuronal Birthdates of Telencephalic Compartments in Situ.
    Date August 1981
    Journal The Journal of Comparative Neurology
    Excerpt

    The birthdates of neuronal populations comprising the chick telencephalon were determined by 3H-thymidine labeling and were mapped with respect to their terminal positions in the 16-day embryo. Essentially all neurons were generated between four and nine days of embryonic development. Each telencephalic structure (based on terminology used by Karten and Hodos, '67) was characterized by a specific range of birthdates: some regions such as the core of the ectostriatum or the paleostriatum primitivum, were generated within a single day, while others, such as the hyperstriatum accessorium, required up to five days for generation of the complete population. Spatial-temporal gradients of neuronal birthdates, lateromedial and ventrodorsal, were seen in the telencephalon as a whole and within individual subcompartments as well. An "outside-in" pattern of histogenesis predominated throughout the entire telencephalon, including the dorsolateral cortex. However, notable exceptions pertaining to the paleostriatum augmentatum, hyperstriatum intercalatus and field "L" were observed. Glial cells, generated for the most part after day ten, were found to be distributed homogeneously throughout all areas of the telencephalon. These data provide the first birthdating data for an avian telencephalon and bring greater resolution to previous analyses of the histogenesis of this brain region. Further, the compartmentalization of the proliferative neuroepithelium is revealed by these data, and the possibility of a common time of origin in the neuroepithelium for neurons of related function is discussed.

    Title 3h-thymidine Autoradiographic Analysis of Telencephalic Histogenesis in the Chick Embryo: Ii. Dynamics of Neuronal Migration, Displacement, and Aggregation.
    Date August 1981
    Journal The Journal of Comparative Neurology
    Excerpt

    The movements of cells from their sites of origin in the proliferative neuroepithelium to their final positions in the chick telencephalon were traced by autoradiographic analysis of 3H-thymidine-labeled brains. A series of chick embryos were labeled on successive days of development between days 5 and 9 and fixed for autoradiography between days 6 and 10. Isochrone maps visualizing neuronal positions on each day of development between days 6 and 10 provided direct information concerning cell migrations, displacements, and aggregations leading to compartmentalization of the telencephalic wall and the generation of the "outside-in" pattern of histogenesis characteristic of the avian telencephalon. The topological divisions of the telencephalic wall appear to result from two factors: (1) the specification of neuronal precursors within the neuroepithelium and (2) the intrinsic associative and migratory properties of postmitotic neuronal populations expressed within the mantle layers. There was no evidence that glial cell barriers mediated the initial compartmentalization of neuronal populations.

    Title Target Neuron-specific Process Formation by Embryonic Mesencephalic Dopamine Neurons in Vitro.
    Date July 1981
    Journal Proceedings of the National Academy of Sciences of the United States of America
    Excerpt

    Mesencephalic dopamine neurons from the embryonic mouse brain were dissociated, aggregated in vitro in the presence of dissociated cells from appropriate or inappropriate target neuron areas, and visualized by the Falck-Hillarp histofluorescence technique after exposure to 1 microM exogenous dopamine. When aggregated with the surrounding rostral mesencephalic tegmentum cells only or with the addition of rostral tectum cells, the dopamine neurons formed a dense dendritic arborization, but no axons were observed. In the presence of dopamine-neuron target cells from the corpus striatum, a dense axonal plexus characteristic of that formed in this area in vivo was observed. In contrast, in aggregates formed with target cells from the frontal cortex, branching fluorescent axons bearing irregularly spaced and shaped varicosities were found coursing through the neuropil, as is characteristic of the dopaminergic innervation to the frontal cortex in vivo. Only proximal dendrites were observed in the presence of these axonal target cells. Dopamine neurons cultured with inappropriate target cells from the occipital cortex did not form either extensive axonal or dendritic processes. Thus, the presence, type, and distribution of dopamine neuronal processes are dependent on the presence of appropriate target cells. The formation of unique patterns of neuronal processes by dissociated neurons in vitro suggests that the information necessary for this differentiation is intrinsic to the dopamine neurons and their target cells. This system provides a useful model with which to study basic mechanisms underlying neuronal recognition.

    Title Utilization of 2,6-diaminopurine by Salmonella Typhimurium.
    Date May 1981
    Journal Journal of Bacteriology
    Excerpt

    The pathway for the utilization of 2,6-diaminopurine (DAP) as an exogenous purine source in Salmonella typhimurium was examined. In strains able to use DAP as a purine source, mutant derivatives lacking either purine nucleoside phosphorylase or adenosine deaminase activity lost the ability to do so. The implied pathway of DAP utilization was via its conversion to DAP ribonucleoside by purine nucleoside phosphorylase, followed by deamination to guanosine by adenosine deaminase. Guanosine can then enter the established purine salvage pathways. In the course of defining this pathway, purine auxotrophs able to utilize DAP as sole purine source were isolated and partially characterized. These mutants fell into several classes, including (i) strains that only required an exogenous source of guanine nucleotides (e.g., guaA and guaB strains); (ii) strains that had a purF genetic lesion (i.e., were defective in alpha-5-phosphoribosyl 1-pyrophosphate amidotransferase activity); and (iii) strains that had constitutive levels of purine nucleoside phosphorylase. Selection among purine auxotrophs blocked in the de novo synthesis of inosine 5'-monophosphate, for efficient growth on DAP as sole source of purine nucleotides, readily yielded mutants which were defective in the regulation of their deoxyribonucleoside-catabolizing enzymes (e.g., deoR mutants).

    Title Self-assembly of Cortical Plate Cells in Vitro Within Embryonic Mouse Cerebral Aggregates. Golgi and Electron Microscopic Analysis.
    Date December 1980
    Journal Brain Research
    Excerpt

    Mouse isocortical cells were dissociated at 18 days of embryonic development and were reaggregated in vitro by rotation in gyratory incubator shaker. The internal organization of the resulting aggregates was studied by conventional light microscopy, Golgi impregnation, and electron microscopy, establishing the following pattern of reassembly: (1) the predominant cell type in the aggregates was the pyramidal neuron; (2) each of these pyramidal neurons tended to orient its apical dendrite toward the surface of the aggregate; and (3) in larger aggregates (diameter > 600 microns) there was prominent parallel alignment of pyramidal cell apical dendrites. These characteristics resulted in an in vitro reconstruction of the major features of isocortex observed in situ, including formation of a superficial, rather acellular plexiform layer. Reconstruction of isocortical architecture appeared to take place independently of either a germinal epithelium, a radial glial framework, or an outer mesenchymal scaffold. Analysis of the events occurring during aggregate formation suggests that intrinsic cellular information accounts for the expression of basic pyramidal cell morphology. However, dendritic orientation and alignment are most likely determined by cell-cell interactions dependent upon specific cell surface recognition properties, as well as by geometric restraints imposed by the spherical or cylindrical shape of the aggregates.

    Title Glutamine and Related Analogs Regulate Guanosine Monophosphate Reductase in Salmonella Typhimurium.
    Date October 1980
    Journal Journal of Bacteriology
    Excerpt

    The addition of a glutamine analog, 6-diazo-5-oxo-L-norleucine, or an inhibitor of glutamine synthetase, L-methionine-dl-sulfoximine, to the growth media of most Salmonella typhimurium strains resulted in a marked elevation of guanosine monophosphate reductase levels. The elevation caused by either compound required protein synthesis and could be antagonized by exogenous glutamine. In addition, when glutamine auxotrophs were grown in suboptimal concentrations of glutamine, the guanosine monophosphate reductase levels were increased. It is postulated that glutamine or a product of its metabolism may function under normal conditions as a negative regulatory element in the control of guanosine monophosphate reductase and that decreased effective intracellular levels of glutamine result in an increase in the level of the enzyme.

    Title Fibronectin Associated with the Glial Component of Embryonic Brain Cell Cultures.
    Date September 1980
    Journal Journal of Supramolecular Structure
    Excerpt

    In the basic approach to investigations of neuronal--glial interactions during both normal brain development and its pathogenesis, embryonic brain cell populations were fractionated into purified neuronal and glial components. Using separation procedures based on differential adhesion and cytotoxicity, the isolated neuronal and glial phenotypes could be identified by distinct morphological and biochemical characteristics, including the visualization of glial fibrillary acid protein (GFA) within glial cells in immunohistochemical assays with monospecific anti-GFA serum. When unfractionated cerebrum cells dissociated from 10-day chick or 14-day mouse embryos were plated as monolayers and cultured for 1--14 days, monospecific antiserum against fibronectin (LETS glycoprotein) was found to react with many, but not all, of the cells as revealed by indirect immunofluorescence microscopy. The isolated neuronal and glial components of these populations were used to determine whether the appearance of membrane-associated fibronectin was characteristic of one cell type or the other, or both, and if neuronal--glial cell interaction was required for its expression. It was found that the surfaces of glial cells, completely isolated from neurons, showed an intense fluorescent reaction to the anti-fibronectin serum. In contrast, the purified neuronal cultures showed no fluorescence with either the anti-GFA or anti-fibronectin sera. These results demonstrate fibronectin as a cell surface protein associated primarily with glial cells and independent of neuronal--glial cell interaction for its expression. Furthermore, the results indicate that the fibronectin observed on glial cell surfaces in these cultures is produced endogenously and is not due to the preferential binding of fibronectin present in the culture medium. The role of fibronectin as an adhesive molecule in neuronal--glial interactions is discussed.

    Title Control of Epithelial Development.
    Date October 1976
    Journal Current Problems in Dermatology
    Excerpt

    Interactions between epidermal and dermal cells of integumental systems exert finely regulated controls over epithelial development. Experimental reconstruction of skin tissues, in vitro and in vivo, from selected populations of dissociated embryonic chick and mouse cells provides a unique opportunity for analyzing the morphogenetic information intrinsic to individual cells. Dermal cells are shown not only to induce and specify particular epithelial structures; they also exercise the power to suppress potential developmental programs. Epidermal cells not only recognize and respond to dermal directives; they are also critical agents in the communication of cues for histogenetic patterning to both neighboring epithelial cells and subadjacent dermal elements. The role of the cell surface as a site for developmental control is discussed in the context of current evidence.

    Title Selective Cell Association of Catecholamine Neurons in Brain Aggregates in Vitro.
    Date October 1976
    Journal Brain Research
    Excerpt

    Brain tissues (aggregates) were reconstructed in vitro from dissociated single cell suspensions derived from 12- to 18-day embryonic mouse midbrain containing the substantia nigra. The application of the Falck-Hillarp histofluorescence method to these cell systems allows the visualization and identification of this specific population of developing catecholamine (CA) neurons during their reassembly, differentiation and histogenetic patterning in vitro. CA neurons are unselectively distributed in the initial dissociated cell suspension and in the reaggregating tissue up to 24 h. By 48 h the CA neurons have selectively associated into small clusters which further coalesce into a thick and elongated band along one margin of the aggregate by 96 h. This structure is similar in organization to the morphology exhibited by substantia nigra neurons in situ during their migratory phase in normal development. In addition, the differentiated neurons observed in the later aggregates appear to produce normal processes. Catecholamine analyses show a significant increase in dopamine and noradrenaline levels during the process of differentiation and histogenetic organization in vitro.

    Title Brain Histogenesis in Vitro: Reconstruction of Brain Tissue from Dissociated Cells.
    Date March 1973
    Journal In Vitro
    Title Reconstruction of Brain Tissue from Cell Suspensions. I. Aggregation Patterns of Cells Dissociated from Different Regions of the Developing Brain.
    Date June 1972
    Journal Developmental Biology
    Title Reconstruction of Brain Tissue from Cell Suspensions. 2. Specific Enhancement of Aggregation of Embryonic Cerebral Cells by Supernatant from Homologous Cell Cultures.
    Date June 1972
    Journal Developmental Biology

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