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Biomedical subjects

A T Cockett

Publications and source records attributed to A T Cockett.

At least 163 records · Page 9Linked to original sources
PubMed1976

Vasectomy and vasovasostomy. I. Timing of histologic changes in immature and mature dog testis after vasectomy.

The effects of vasectomy on the development and maintenance of spermatogenesis was studied using immature and mature dog testes. Bilateral vasectomy in immature dogs delayed the development of advanced spermatocytes, spermatids, and spermatozoa for about 3 months postsurgery. Spermatogenesis appeared to be recovered to control levels by 4 months postvasectomy. Spermatogenesis in mature dogs was also altered after bilateral vasectomy. Decreased numbers of advanced spermatocytes as well as maturation arrest was observed by 3 weeks postvasectomy. Seminiferous tubule cell layers quickly decreased to one to three layers as the lumina became occluded with sloughed cells by 3 to 6 weeks postvasectomy. Recovery in terms of the numbers of spermatocytes, spermatids, and spermatozoa was evident by 13 weeks postvasectomy, although occasional dog testes did not recover and appeared to be more sensitive to vasectomy-induced damage. It thus appears that vasectomy temporarily inhibits both the development and maintenance of spermatogenesis in immature as well as mature dog testes. Spermatogenesis does recover but may be maintained at somewhat lower levels after vasectomy. Changes are rapid in onset and take several weeks to be reversed. Some dog testes appear to be more sensitive to the damage and it may be irreversible in these testes.

Animals↗
PubMed1976

Vasectomy and vasovasostomy. II. A comparison of two methods of vasovasostomy: silastic versus chromic stents.

Twelve adult, bilaterally vasectomized dogs were used to compare two different procedures for reuniting the severed vas deferens. Approximately 5 months postvasectomy six dogs had vasovasostomies utilizing Silastic stents and the vasa deferentia of six additional dogs were rejoined with intravasal chromic stents. Ejaculates were subsequently obtained at 2-week intervals and evaluated for sperm count, motility, viability, and seminal ion concentrations. All of the dogs in which Silastic had been utilized as the stent had sperm reappear in the ejaculate, whereas only 40% of the dogs in which chromic catgut had been utilized had reappearance of spermatozoa. The over-all quality of the ejaculate was also better in the animals in which Silastic had been utilized. Testicular and epididymal histology was normal in most dogs of both groups, but three of the dogs with chromic stents in which the anastomosis had not been a success had abnormal histology, with reduced numbers of spermatocytes, spermatids, and spermatozoa. The data suggest that Silastic stents are better than chromic stents for vas reanastomosis. They also suggest that some dog testes react negatively to vasectomy and do not recover by 1 year postvasectomy when vas patency is not reversed.

Animals↗
PubMed1976

Age-related changes in male rat reproductive organ weights and plasma testosterone concentrations after administration of a monoamine oxidase inhibitor.

Experiments were conducted to determine the effects of pargyline, a monoamine oxidase inhibitor, onmale rat reproductive organ weights, testicular histology, and plasma testosterone levels. Pargyline was administered to various groups of rats by implanting it, either dissolved or in a powder form, in Silastic tubing capsules. Additional rats were injected with pargyline solutions. The effects of pargyline.appeared to be age-related with younger animals, weighing under 400 gm (less than 100 days of age), showing a decrease in testicular and accessory organ weights and plasma testosterone. Older animals did not show a decrease in organ weights. Testicular histology in the pargyline-treated groups showed sloughage of cellular material into the tubular lumina, decreases in the number of cell layers, and a reduction of the number of mature spermatocytes. Other areas in the same testis were normal, however, and resembled control histology. The results suggest that pargyline can have detrimental effects on testicular function and that the effects may be age-related.

Age Factors↗
PubMed1976

Correlation between follicle stimulating hormone, luteinizing hormone, testosterone and 5-hydroxyindole acetic acid with sperm cell concentration.

Plasma follicle stimulating hormone, luteinizing hormone, testosterone, urinary 5-hydroxyindole acetic acid and 17-ketosteroids were measured in patients seen at an infertility clinic. Plasma follicle stimulating hormone and luteinizing hormone levels, and urinary 5-hydroxyindole acetic acid levels were increased in patients with sperm concentrations less than 10 times 10(6) per ml. The results suggest that in patients with sperm counts less than 10 times 10(6) per ml. there is not only impaired spermatogenesis but also decreased Leydig cell function. Urinary 17-ketosteroid levels were not related to sperm cell concentration.

17-Ketosteroids↗
PubMed1976

Percutaneous nephropyelostomy in the management of acute pyohydronephrosis.

Percutaneous nephropyelostomy using the posterolateral approach was employed together with antibiotics and other supportive therapy as the initial step in the treatment of acute pyohydronephrosis, with gratifying results. Percutaneous nephropyelostomy is recommended as the procedure of choice for this specific clinical emergency.

Acute Disease↗
PubMed1976

Elevated urinary levels of 5-hydroxyindole acetic acid and its relationship among levels of plasma follicle stimulating hormone, testosterone and testicular pathology in patients with severe oligospermia and/or azoospermia.

Plasma follicle stimulating hormone, testosterone and urine 5-hydroxyindole acetic acid levels were measured in 300 patients seen at an andrology clinic. Testicular biopsies were obtained from many of the severely oligospermic or azoospermic patients. Plasma follicle stimulating hormone concentrations were related inversely to sperm cell concentration, while plasma testosterone concentrations were depressed as the sperm count decreased to 5 times 106 per ml. The urine levels of 5-hydroxyindole acetic acid followed the same pattern as follicle stimulating hormone and were elevated in the group of individuals with sperm counts less than 10 times 106 per ml. Elevations in 5-hydroxyindole acetic acid often were associated with abnormalities in the testicular biopsy. Only 30 per cent of the patients who had elevated 5-hydroxyindole acetic acid also had elevated follicle stimulating hormone or depressed testosterone levels. The factors responsible for the elevation in 5-hydroxyindole acetic acid levels as the sperm count declines remain unclear.

Follicle Stimulating Hormone↗
PubMed1976

Caffeine, theophylline, and human sperm motility.

Concentrations of 10(-2), 10(-3), 10(-4), 10(-5), or 10(-6) M caffeine and theophylline were added to semen samples to determine the effects of these compounds on several parameters of semen quality. Semen samples were incubated at 37 degrees C and observed 0.5,1,2,4, and 6 hours after addition of the respective compounds. Semen quality was determined by estimating the percentage of active spermatozoa, by estimating sperm motility, and by counting the number of viable sperm at each time interval. Neither of the compounds, at any of the dose levels tested, had any significantly different effects on the quality of sperm motility or the percentage of active or viable spermatozoa, although a few samples responded favorably to these compounds. Noted improvements in semen quality did not appear to be dependent on the initial semen quality. The data contradict previous reports and suggest that methyl xanthines do not have beneficial effects on the majority of semen samples obtained from men seen at a fertility evaluation clinic.

Animals↗
PubMed1976

Hormonal control of seminiferous tubule contractions. A hypothesis of sperm transport from the testicle.

The effects of steroids on the presence or absence and relative magnitude of rat seminiferous tubule contractions were evaluated microscopically. Both 10- and 30-mg implants of estradiol in vivo and concentrations of 10(-8) or 10(-9) M estradiol in vitro depressed the percentage of seminiferous tubules contracting without altering the magnitude of the contraction. Higher doses of both testosterone and dihydrotestosterone in vivo and in vitro maintained the tubular contractions at normal or above normal levels whereas lower doses of these compounds reduced both the percentage and magnitude of the tubules contracting. The results from these experiments suggest that rat seminiferous tubule contractions can be altered by steroids. Testosterone and dihydrotestosterone inhibit the contractions at lower doses and stimulate the contractions at higher doses and thus may regulate the transport of spermatozoa from the rat testicle.

Animals↗
PubMed1975

A comparison of subjective measurements of human sperm motility and viability with two live-dead staining techniques.

Two commonly used live-dead stains (eosin-nigrosin (EN) and eosin-opal blue (EOB)) were compared with the estimated active spermatozoa in semen samples from patients attending an infertility service. Twenty-eight semen samples were analyzed throughout the day of their collection by estimating the number of active spermatozoa and by staining a portion of the incubated sample (37 degrees C) with each stain. The samples were analyzed 30, 60, 120, 240, and 360 minutes after the initial collection. At 30 minutes there were no significant differences between the estimated values and those of either stain. The slope of the EN stain closely paralleled that of the estimated measurements throughout the remainder of the time periods, while the EOB slope was somewhat steeper. Repeatability of values for semen samples obtained on different days was generally good for each stain. A comparison of semen samples from 85 patients, 30 minutes after collection, showed no significant differences between the numbers of estimated active sperm and the percentage live using the EN stain. Studies of 132 semen samples using the EN stain showed a positive correlation with the over-all quality of sperm motility. The results indicate that there is a role for live-dead staining in assessing semen quality.

Cell Biology↗
PubMed1975

Recent advances in the diagnosis and management of blunt renal trauma.

Experience with 207 cases of blunt renal trauma is reviewed. We have found that renal scans and selective renal arteriography are the most informative diagnostic tests. However, in a small community setting we suggest use of an infusion urogram and a retrograde pyelogram. Our accuracy rates with these 4 diagnostic tests are listed and selected cases are illustrated. We believe that if exploration is warranted, kidney salvage rates will be improved because of an accurate assessment of the extent of renal injury.

Accidents, Traffic↗
PubMed1975

Semen analysis: a review of samples from 225 men seen at an infertility clinic.

The results from 225 men attending an infertility clinic are presented. The percentage of oval, viable and active sperm cells, and the motility scores were lower in samples with counts less than 10 times 10(6) per ml., increased in counts or 10 to 40 times 10(6) per ml. and again increased in counts more than 40 times 10(6) per ml. The percentage of semen samples with abnormalities in measured parameters dramatically increased as the sperm count decreased. The percentage of samples with significant numbers of white blood cells was higher in samples with sperm counts less than 10 times 10(6) per ml. and in the azoospermic patients, while viscosity problems seemed to be associated with counts less than 10 times 10(6) per ml. Agglutination was more of a problem in samples with counts more than 40 times 10(6) per ml.

Cell Count↗
PubMed1975

Correlation between follicle stimulating hormone, luteinizing hormone, testosterone and 5-hydroxyindole acetic acid with sperm cell concentration.

Plasma follicle stimulating hormone, luteininzing hormone, testosterone, urinary 5-hydroxyindole acetic acid and 17-ketosteroids were measured in patients seen at an infertility clinic. Plasma folicle stimulating hormone and luteinizing hormone levels, and urinary 5-hydroxyindole acetic acid levels were increased in patients with sperm concentrations less than 10 times 10(6) per ml. Plasma testosterone levels were lower in patients with sperm concentrations less than 10 times 10(6) per ml. The results suggest that in patients with sperm counts less than 10 times 10(6) per ml. there is not only impaired spermatogenesis but also decreased Leydig cell function. Urinary 17-ketosteroid levels were not related to sperm cell concentration.

17-Ketosteroids↗