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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of urology 3 (1996), S. 0 
    ISSN: 1442-2042
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: We evaluated the effects of chronic renal failure on hypothalamo-pituitary-testicular axis function in male Wistar rats. Methods: Chronic renal failure was induced by five-sixths nephrectomy in male rats. Seven to 10 weeks after the surgery, serum urea and creatinine concentrations and hematocrits were evaluated, and human chorionic gonadotropin (hCG) and gonadotropin-releasing hormone (GnRH) tests, and prolactin stimulating antl suppression tests were performed. In addition, androgen-binding protein, epididymal sperm content, motility, ancl fertile potential were assessed. Results: Basal serum testosterone concentrations and the response of testosterone to hCG were significantly lower in rats with chronic renal failure than in controls. Basal serum gonadotropin levels were elevated in rats with chronic renal failure, but the gonadotropin response to GnRH did not differ from that in controls. Serum protactin IeveIs responded appropriately to stimuIation and suppression tests. Androgen-binding protein levels, epididymal sperm content, motility, and fertile potential were significantly lower in uremic rats. Conclusions: Chronic rend failure in rats interferes with endocrinologic mechanisms and testicular functions. Thus, uremic rats have a low fertile potential.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-7330
    Keywords: fertility ; rabbit ; round spermatid ; laser microscope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose Our purpose was to investigate the possibility of achieving fertilization and subsequent normal embryonic development by injecting round spermatid nuclei into rabbit oocytes. Results Two- to four-cell-stage embryos developed after round spermatid nuclear injections into rabbit ooplasma could further develop in vitro up to the expanding blastocyst stage or in vivo up to complete gestation. Conclusion The current findings show that the haploid set of chromosomes of round spermatid can pair with the chromosomes of the ootid to participate in complete fertilization and subsequent embryonic and fetal development. In addition, we suggest that postmeiotic modifications of the round spermatid are not required for the pairing of male gamete chromosomes with those of the ootid.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-0879
    Keywords: Key words Spermatocyte ; Spermatid ; Telomerase ; Testis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated whether testicular telomerase activity is due to telomerase expression in all cells or expression in a limited number of cells. Telomerase activity was assayed in highly purified fractions of spermatogonia cells plus primary spermatocytes, secondary spermatocytes plus round spermatids, secondary spermatocytes plus spermatids plus spermatozoa, round spermatids, or spermatozoa prepared from healthy or cryptorchid animals. Telomerase activity was additionally assayed in testicular tissue of prepubertal animals and animals with Sertoli cell only pathophysiology. Telomerase activity was detected in fractions containing primary spermatocytes and/or secondary spermatocytes and/or spermatids. Fractions enriched in round spermatids were positive for telomerase activity. In contrast, spermatozoa or Sertoli cell fractions were negative for telomerase activity. Using the relative telomerase activity assay and the sensitive quantitative telomerase assay to quantify telomerase activity, we showed that induction of cryptorchidism does not result in quantitative alterations in testicular tissue telomerase activity. In addition, elimination of round spermatids does not lead to significant alterations in testicular tissue telomerase activity. The present results suggest that the male gamete telomerase activity is inhibited during spermiogenesis. Furthermore, it appears that spermatogonia/primary spermatocytes are the main sources of telomerase activity in the testis.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1434-0879
    Keywords: Key words Testicular function ; Smoking ; Fertility ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We evaluated the effects of smoking on testicular function and fertilizing potential in rats. Twenty rats (group A) were exposed to the smoke of 20 cigarettes for 1 h per day. Ten rats (group B) were exposed to the smoke of 40 incense sticks for 1 h per day, and an additional 10 rats served as a control group (group C). After 10 weeks of daily exposure, serum levels of nicotine and cotinine were assessed, and a mating test was conducted. Five days later, serum concentrations of testosterone before and after human chorionic gonadotropin (hCG) stimulation, gonadotropins, and epididymal sperm content and motility were evaluated. In addition, in vitro fertilization was carried out. Nicotine and cotinine were detected in group A, but not in groups B and C. Basal serum testosterone and gonadotropin concentrations did not differ significantly among the three groups, but the testosterone response to hCG stimulation was significantly lower in group A than in groups B and C. Group A showed significant reductions in epididymal sperm content and motility, and in fertility in vivo and in vitro. These findings suggest that smoking leads to a secretory dysfunction of the Leydig cells, and also a deficiency in sperm maturation and spermatogenesis. In addition, smoking has a detrimental effect on sperm fertilizing potentials in vivo and in vitro.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-0879
    Keywords: Key words Smoking ; Cotinine ; Sperm ; Fertilization ; Oocyte activation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We evaluated the effect of cotinine on sperm fertilizing capacity in vitro. Human spermatozoa were washed and re-suspended in medium containing albumin and various concentrations of cotinine (0, 100, 200, 400, or 800 ng/ml). After an 8-h incubation period, sperm motility, hypoosmotic swelling test (HOST) outcome, and the percentage of hyperactivated spermatozoa were assayed. Aliquots of spermatozoa were then processed for the zona-free hamster oocyte sperm penetration assay (SPA) or hamster ooplasmic injections. Spermatozoa exposed to concentrations of cotinine equal to 400 or 800 ng/ml demonstrated significantly smaller outcomes for all of the above with the exception of after hamster ooplasmic injections, where high cotinine concentrations did not affect sperm viability or sperm capacity to undergo decondensation and activate hamster oocytes. It appears that cotinine concentrations of 400 or 800 ng/ml exert a detrimental effect on sperm motility, membrane function, and the ability to undergo capacitation. In addition, the current findings suggest that smokers with a high seminal plasma cotinine concentration who participate in assisted reproduction programs may be treated with intracytoplasmic sperm injections (ICSI) rather than conventional in vitro fertilization (IVF) trials.
    Type of Medium: Electronic Resource
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