Natan Bar-Chama

Identification and characterization of repopulating spermatogonial stem cells from the adult human testis

BACKGROUND This study was conducted to identify and characterize repopulating spermatogonial stem cells (SSCs) in the adult human testes. METHODS Testes biopsies from obstructive azoospermic patients and normal segments of human testicular tissue were used. Flow cytometry, real-time PCR and immunohistochemical analysis were performed. Purified human spermatogonia were transplanted into busulfan-treated recipient mouse testes and integrated cells were detected by human nuclear protein antibody co-localized with stem cell and germ cell markers. RESULTS Testicular biopsies collected from obstructive azoospermic men showed similar morphology and distribution of markers to the normal human testes. Flow cytometry showed distinct populations of stage-specific embryonic antigen-4 (SSEA-4), CD49f and CD90 positive cells in the adult human testes. SSEA-4 (+) cells showed high expression levels of SSC-specific genes and high levels of telomerase activity. Extensive colonization of human cells in the mouse testes indicates the presence of highly enriched populations of SSCs in the SSEA-4 (+) sorted cells. All the HNP (+) cells in the mouse testes were positive for germ cell marker dead box mRNA helicase and only half of them were dimly positive for c-kit. In addition, subpopulations of human spermatogonia that colonized mouse testes were positively stained for CD49f, GPR-125, Nanog and Oct-4 indicating the existence of population of cells among human spermatogonia with SSC and pluripotent characteristics. CONCLUSIONS This study clearly demonstrates that repopulating human SSCs have phenotypic characteristics of SSEA-4(+), CD49f(+), GPR-125(+)and c-Kit (neg/low). The results have direct implications for enrichment of human spermatogonia for further culture and germ cell differentiation studies.

Paternal age and assisted reproductive technology outcome in ovum recipients

This study suggests that paternal age may be inversely associated with reproductive outcome, as demonstrated by a decline in fertilization, blastocyst formation, implantation and cryopreservation rates with advancing age.

Accuracy of semen counting chambers as determined by the use of latex beads

OBJECTIVE To assess the accuracy of the Hemacytometer (Hausser Scientific, Horsham, PA), Makler (Sefi-Medical Instrument, Haifa, Israel), Cell-VU (Millennium Sciences Inc., New York, NY), and Micro-Cell chambers (Conception Technologies, San Diego, CA) counting chambers. DESIGN A solution containing a known concentration of latex beads was used as the standard to perform counts on the four different counting chambers. MAIN OUTCOME MEASURES Bead counts for the four different chambers were compared with the bead counts of the standard solution. Variability within chambers also was determined. RESULTS Mean bead concentrations for both the Cell-VU and Micro-Cell chambers were consistently similar to the bead concentration of the standard solution. Both the hemacytometer and the Makler chambers overestimated the actual bead concentration of the standard solution by as much as 50% and revealed significant interchamber variability. CONCLUSIONS Our data revealed marked differences in the accuracy and reliability of the different counting chambers tested and emphasized the need for standardization and quality control of laboratory procedures.

Direct Exposure of Mouse Spermatogenic Cells to High Doses of Adenovirus Gene Therapy Vector Does Not Result in Germ Cell Transduction

The potential for adenovirus gene therapy vectors to gain access to male germ cells was rigorously tested in the mouse by injecting high titers of the vector directly into the testis and epididymis, or by exposing sperm to the vector immediately prior to or during in vitro fertilization. The adenovirus vector carried the bacterial lacZ gene (Adbeta-Gal) driven by the Rous sarcoma virus (RSV) promoter, and infection was assessed by testing for lacZ expression, either with antibodies to LacZ protein or by staining for LacZ enzymatic activity. A total of 109 plaque-forming units (PFU) was inserted into the testis or epididymis, and in vitro fertilization was performed after sperm were exposed either to 10 or 100 PFU per sperm cell. lacZ expression was examined within testes for several weeks after injection, and in preimplantation embryos produced by in vitro fertilization with sperm exposed to the gene therapy vector. Direct injection of Adbeta-Gal into either the testis or epididymis resulted in lacZ expression only within the interstitium of the testis and not within seminiferous tubules. Despite direct exposure of spermatogenic cells or mature sperm to high titers of virus, lacZ expression was likewise not detected in embryos. These findings are consistent with the conclusion that the risk is minimal for germ line integration of adenovirus vectors exposed to male reproductive cells.

Acceptability and Preliminary Feasibility of an Internet/CD-ROM-Based Education and Decision Program for Early-Stage Prostate Cancer Patients: Randomized Pilot Study

Background Prostate cancer is the most common cancer affecting men in the United States. Management options for localized disease exist, yet an evidence-based criterion standard for treatment still has to emerge. Although 5-year survival rates approach 98%, all treatment options carry the possibility for significant side effects, such as erectile dysfunction and urinary incontinence. It is therefore recommended that patients be actively involved in the treatment decision process. We have developed an Internet/CD-ROM-based multimedia Prostate Interactive Educational System (PIES) to enhance patients’ treatment decision making. PIES virtually mirrors a health center to provide patients with information about prostate cancer and its treatment through an intuitive interface, using videos, animations, graphics, and texts. Objectives (1) To examine the acceptability and feasibility of the PIES intervention and to report preliminary outcomes of the program in a pilot trial among patients with a new prostate cancer diagnosis, and (2) to explore the potential impact of tailoring PIES treatment information to participants’ information-seeking styles on study outcomes. Methods Participants (n = 72) were patients with newly diagnosed localized prostate cancer who had not made a treatment decision. Patients were randomly assigned to 3 experimental conditions: (1) control condition (providing information through standard National Cancer Institute brochures; 26%), and PIES (2) with tailoring (43%) and (3) without tailoring to a patient’s information-seeking style (31%). Questionnaires were administrated before (t1) and immediately after the intervention (t2). Measurements include evaluation and acceptability of the PIES intervention, monitoring/blunting information-seeking style, psychological distress, and decision-related variables (eg, decisional confidence, feeling informed about prostate cancer and treatment, and treatment preference). Results The PIES program was well accepted by patients and did not interfere with the clinical routine. About 79% of eligible patients (72/91) completed the pre- and post-PIES intervention assessments. Patients in the PIES groups compared with those in the control condition were significantly more likely to report higher levels of confidence in their treatment choices, higher levels of helpfulness of the information they received in making a treatment decision, and that the information they received was emotionally reassuring. Patients in the PIES groups compared with those in the control condition were significantly less likely to need more information about treatment options, were less anxious about their treatment choices, and thought the information they received was clear (P < .05). Tailoring PIES information to information-seeking style was not related to decision-making variables. Conclusions This pilot study confirms that the implementation of PIES within a clinical practice is feasible and acceptable to patients with a recent diagnosis of prostate cancer. PIES improved key decision-making process variables and reduced the emotional impact of a difficult medical decision.

Male reproduction and environmental and occupational exposures: A review of epidemiologic methods

Concerns that chemical exposures in the environment have been detrimental to male sexual development and fertility have been heightened by reports of declining sperm counts over the past 50 years. Marked geographic variation has been found in semen quality and in the incidence of testicular cancer and certain urogenital defects. Debate continues over the existence, magnitude and significance of these trends, and how best to evaluate the hypothesis that in utero and childhood exposures to estrogenic compounds may be to blame. Epidemiologic methods for assessing the impact of hazardous substances on male reproductive health have been developed mainly in the area of occupational medicine, and this paper will review the currently recommended methods. These include questionnaires to determine reproductive history and sexual function; reproductive hormone profiles; and semen analyses such as sperm concentration, motility, and morphology. New research tools that show significant promise from the fields of clinical reproductive medicine and reproductive toxicology are discussed as possible additions to epidemiologic studies, including assays of sperm function and genetic integrity, and biomarkers of DNA damage. For population-based studies involving occupational groups or communities with environmental exposures, issues related to the cost, validity, precision and utility of these methods must be carefully considered.

Initial experience with processed human cadaveric allograft skin for reconstruction of the corpus cavernosum in repair of distal extrusion of a penile prosthesis

We describe our initial experience with the novel application of processed human cadaveric allograft skin in reconstruction of a damaged corpus cavernosum associated with distal extrusion of a penile prosthesis. The material was evaluated for ease of reconstruction, adequacy of repair, and outcome. Human processed dermis allograft requires no intraoperative harvesting, is technically easy to fashion, and offers adequate tensile strength in the reconstruction of damaged corpora cavernosa. This initial experience with processed human cadaveric dermis in reconstruction of damaged corpora cavernosa is encouraging. Further evaluation to define the long-term efficacy and scope of application of this material in urologic reconstructive procedures is warranted.

Medical implications of erectile dysfunction.

Erectile dysfunction (ED) is a common condition in aging men, with a prevalence of 52% in men aged 40 to 70 years. It is frequently associated with several comorbid conditions, including cardiovascular disease, lower urinary tract symptoms, and testosterone deficiency. These conditions often have major consequences on the quality of life of patients and require adequate evaluation by the primary care practitioner. Complaints of ED, therefore, serve as a marker for these conditions and give the practitioner an opportunity to prevent the consequences of a delay in treatment. In this article, the evidence behind these associations is described.

Intratesticular mucinous cystadenoma: immunohistochemical comparison with ovarian and colonic tissue.

We report a case of a primary intratesticular mucinous cystadenoma in an asymptomatic 39-year-old man. The mass was found incidentally during a consultation for infertility. Pathologic examination of the orchiectomy specimen revealed a unilocular cyst lined with bland mucinous epithelium and mucinous extravasation, consistent with a diagnosis of mucinous cystadenoma. Foci of bone were also found in association with extensive chronic inflammation. Immunohistochemical stains performed showed immunoreactivity for cytokeratin 7, and nonreactivity for cytokeratin 20, CA125, chromogranin, and synaptophysin. The immunohistochemical staining patterns of the present case are compared with those of known mucinous cystadenomas of the ovary and nonneoplastic colonic mucosa. The histogenesis of this entity is discussed in light of the literature and the immunohistochemical findings in this rare case.

Erectile dysfunction and infertility

Infertility is common and associated with distress, anxiety, and depression, all of which can result in sexual dysfunction. This stress-related erectile dysfunction can be effectively treated with oral phosphodiesterase type 5 inhibitors. A review of the current literature suggests that phosphodiesterase type 5 inhibitors have no detrimental effects on human semen parameters or hormonal milieu. Physicians treating infertile couples should be aware of the association between erectile dysfunction and infertility and be proactive in inquiring and treating infertility-induced erectile dysfunction.