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Biomedical subjects

E Steinberger

Publications and source records attributed to E Steinberger.

At least 37 records · Page 2Linked to original sources
PubMed1982

Circannual rhythm in human sperm count revealed by serially independent sampling.

Sperm concentration and total sperm counts from single semen and samples from each of 4435 patients requesting vasectomy between September 1972 and December 1977 were analyzed for circannual (about 1 year) rhythmicity. Although large temporal variations were found both between years and within years, a trend was noted for higher sperm concentration during the winter than during the summer. When the entire series of data were analyzed by months, a strong circannual pattern was apparent, with the highest sperm counts between February and March and the lowest counts during September. To the authors' knowledge, this is the first report of a circannual rhythm in human sperm concentration and total sperm count. The data must be considered preliminary, but if confirmed by other investigators studying comparable populations, the influence on clinical investigations will be profound.

Adult↗
PubMed1982

Binding of 3H-Sertoli cell factor to rat anterior pituitary in vitro.

The binding characteristics of Sertoli Cell Factor (SCF) to the anterior pituitaries were examined using tissue homogenates and cultured cells. Tritium-labeled SCF (3H-SCF), synthesized by rat Sertoli cells in vitro in the presence of 3H-leucine and partly purified by Sephadex gel chromatography, was used to the ligand. The binding of 3H-SCF to the pituitary homogenates or cultured cells was considerably greater (3-6X) compared to homogenates of brain, kidney, liver, spleen and testis. The pituitary binding at 37 C occurred after approximately 60 time dependent, and directly related to the receptor concentration. Maximum binding at 37 C occurred after approximately 60 min of incubation. Over 90% of the bound 3H-SCF was competitively inhibited by an excess of unlabeled SCF, but not by other substances. There was a good correlation between the binding of 3H-SCF and its biological activity, as evidenced by a selective suppression of basal FSH release in pituitary cell cultures. These data indicate that, in analogy to other protein hormones, specific binding to target cell receptors may represent an initial step of SCF action in the pituitary. The binding should also prove valuable in the development of a rapid radio-receptor assay for SCF and possibly for other inhibin preparations.

Animals↗
PubMed1982

Conversion of progesterone by testicular tissue of cryptorchid rats.

The capacity of adult rat testes rendered surgically cryptorchid to metabolize progesterone was investigated at several time intervals (7, 14, 28 and 42 investigated at several time intervals (7, 14, 28 and 42 days) after surgery. Testicular tissue was incubated with [3H]progesterone, the steroid metabolites were isolated and purified using paper and thin layer chromatography, and further identified by isotopic dilution and recrystallization to constant 3H/14C ratio or constant specific activity (DPM/mumol). A sharp decrease in the accumulation of testosterone, concomitant with a marked increase in accumulation of 17 alpha-hydroxyprogesterone, was observed as early as 7 days after surgery. No further major changes were observed at 14 or 28 days after surgery. However, at 42 days, accumulation of testosterone was substantially increased, while that of 17 alpha-hydroxyprogesterone decreased to trace levels. 20 alpha-Dihydroprogesterone was detected at different time intervals after surgery. The data suggest that cryptorchidism inhibits the activity of 17-20 desmolase for the first 4 weeks after surgery. The activity of this enzyme is restored by the 42nd day and the metabolic pathway between progesterone and testosterone resembles that of an intact rat. The factors responsible for this spontaneous restoration of the biosynthetic pathway are under investigation.

17-alpha-Hydroxyprogesterone↗
PubMed1982

Further characterization of the molecular species formed during the biosynthesis of rat luteinizing hormone.

During the biosynthesis of rat LH (rLH) there are four molecular species found intracellularly: native rLH, a species which co-elutes with rLHalpha on Sephadex G-100, a species which elutes with an apparent molecular weight of approximately 21 000 and a large molecular weight form (excluded from Sephadex G-100). Significant quantities of native rLH and rLHalpha are secreted. The species of large molecular weight binds to Concanavalin A-Sepharose suggesting that it is glycosylated. The 21 000 molecular weight rLH-like molecule has tentatively been identified as an rLH subunit which has not been completely processed.

Animals↗
PubMed1982

The epidemiologic assessment of male reproductive hazard from occupational exposure to TDA and DNT.

Dinitrotoluene (DNT) and toluene diamine (TDA) are intermediates in the production of toluene diisocyanate and polyurethane plastics. Some reproductive effects in rodents have been reported; and the National Institute for Occupational Safety and Health reported probable reproductive toxic effect to humans after a preliminary survey. Accordingly, 84 workers exposed to DNT/TDA (classified by intensity and recency of exposure) and 119 nonexposed workers were studied at Olin's chemical complex at Lake Charles, La. Each worker was the subject of a physician's urogenital examination, a reproductive and fertility questionnaire, an estimation of testicular volume, an assessment of serum follicle-stimulating hormone, and an analysis of semen for sperm count and morphology. No differences were found between the exposed and control groups among any of these variables. Although both TDA and DNT are readily absorbed (percutaneous, inhalation, ingestion), they did not present detectable reproductive hazard to the workers.

Adult↗
PubMed1981

Varicocele and the morphology of spermatozoa.

It is believed that varicocele is characteristically associated with specific abnormalities of spermatozoal morphology (increased numbers of tapered and amorphous forms). This report summarizes the results of a prospective study of spermatozoal morphology in 208 male partners of infertile couples seen consecutively during an 18-month period. After exclusion of 23 azoospermic males, sperm morphology in the remaining 56 patients with varicocele and 129 men without varicocele were compared. Although the incidence of abnormal spermatozoa was higher in patients with varicocele, no significant differences in the patterns of morphology were observed. In both groups of patients the percentage of normal spermatozoa was significantly correlated with the sperm count and with percentage motility. Sperm count and motility were significantly correlated with each other. The percentages of tapered and amorphous spermatozoa were inversely correlated with the motile sperm count. These results demonstrate that the pattern of spermatozoal morphology observed in men with varicocele is not characteristic or unique to this condition. It appears that abnormality of spermatozoal morphology is commonly associated with diminished sperm count and motility, regardless of the presence or absence of a varicocele.

Humans↗
PubMed1981

The influence of ovulatory dysfunction and timing of insemination on the success of artificial insemination donor (AID) with fresh or cryopreserved semen.

The influence of ovulatory dysfunction and timing of insemination on the success of AID with either fresh or cryopreserved semen was investigated. A total of 238 patients were inseminated, resulting in 170 pregnancies during 1201 insemination cycles, an average of 5.0 cycles per pregnancy. Pregnancy rates were similar in those patients receiving either fresh or cryopreserved semen, but the number of cycles required for pregnancy to occur was doubled in the latter group. Ovulatory dysfunction further delayed the number of cycles before conception. The poorest results occurred in those patients with ovulatory dysfunction receiving cryopreserved semen. The timing of insemination was more important in patients receiving cryopreserved semen than those receiving fresh semen. With cryopreserved semen, pregnancy was not likely to occur unless the insemination was performed on the day of ovulation. These data suggest that frozen semen is less efficacious than fresh semen, a difference that is compounded by the presence of ovulatory dysfunction in the recipient. It is possible that an increase in the frequency of insemination from every other day to daily may improve the results of AID with cryopreserved semen.

Evaluation Studies as Topic↗
PubMed1981

The menstrual cycle and plasma testosterone levels in women with acne.

A prospective study of the ovarian function and plasma testosterone levels was conducted in a group of 139 women presenting with a chief complaint of acne. In 90% of the patients the plasma testosterone levels were above the normal mean. Amenorrhea was present in 17.2%, anovulation in 18.4%, and variable degree of ovulatory dysfunction in 57.2% of the patients. The severity of ovarian dysfunction was directly proportional to the plasma testosterone levels. Age was inversely related to both plasma testosterone levels and severity of ovarian dysfunction. The results of this study suggest that acne may be associated not only with a hyperandrogenic state but also with ovarian dysfunction. They emphasize the need for a careful investigation of androgen levels and ovarian function in women with chief complaint of acne.

Acne Vulgaris↗
PubMed1981

Current status of studies concerned with evaluation of toxic effects of chemicals on the testes.

A brief review of the history of the subject is provided. An attempt is made to define the current status of the knowledge and the reasons why our knowledge in this area of science is poor. The information gained from studies employing lower species is contrasted with information on the human male. The most commonly utilized techniques for evaluating the effects of toxic agents on the male reproductive system is briefly summarized. The growth of knowledge in physiology, biochemistry, and hormonal control of testicular function during the past ten to fifteen years is discussed; and, the specific most pertinant advances are noted. The difficulties in utilizing the human subject for toxicologic studies are pointed out and the reasons why the knowledge of the effect of toxic agents on the human testes are meager are discussed. The methodology utilized for the study of the functional integrity of the human testes and the specific parameters widely utilized for this purpose are discussed and criticized. The fact that it is extremely difficult to evaluate changes in the testicular function of men are emphasized and the extremely wide variability is pointed out. Furthermore, it is demonstrated that at this moment, we are lacking some of the most fundamental information concerning the normal function of the human testes; and, that there is a poor understanding of parameters of "normalcy". The three parameters used most commonly to define normalcy of human testes, namely, testicular histology, sperm output, and hormonal levels are discussed and the difficulties and pitfalls of these measurements are pointed out.

Animals↗
PubMed1981

Effects of oestradiol benzoate (OeB) and human chorionic gonadotrophin (hCG) on the testes and accessory sex glands of the rat.

It has been suggested that treatment of intact male rats with oestradiol benzoate (OeB) causes an interference with testosterone (T) production by the testes by a direct inhibitory effect on steroidogenesis. To test this hypothesis, different doses (5, 10 or 25 IU) of hCG were administered concomitantly with 50 microgram of OeB to adult intact or hypophysectomized male rats. The testicular and plasma testosterone, and serum hCG levels were determined. The sex accessory weights were recorded. In the intact OeB-treated group of animals, hCG stimulated both the secondary sex organs and plasma testosterone levels above the intact control group. However, in hypophysectomized animals, although plasma testosterone levels increased above that of intact controls, their secondary sex organ weights did not. Moreover, inspite of high circulating hCG levels, the testicular testosterone content and concentration remained suppressed in OeB-treated animals. The reason for such dichotomy of hCG action on OeB-treated animals is not clear at present.

Animals↗
PubMed1980

Survey and analysis of educational efforts in reproductive biology and human sexuality in American medical schools.

One hundred eighteen American medical schools were surveyed in 1976 regarding their efforts to educate physicians in reproductive biology and human sexuality. Ninety-seven of the schools responded. From the material supplied by the respondents detailed analyses of the content of courses, clerkships and electives were made. Several topics are always included in courses in reproductive biology while a number of important areas are very neglected. In schools without organized courses materials are not well integrated in the curriculum. The content of human sexuality courses and electives is highly individualistic and varies greatly from school to school.

Biology↗
PubMed1979

Testosterone levels in female partners of infertile couples. Relationship between androgen levels in the woman, the male factor, and the incidence of pregnancy.

Plasma testosterone levels were measured in the female partners of 146 consecutive infertile couples. The incidence of hyperandrogenism in the woman was correlated with ovarian function, incidence of pregnancy, male factor, and response of plasma testosterone levels to prednisone treatment. Over 70 per cent of the patients had pretreatment testosterone levels above 40 ng. per 100 ml. while after a minimum of two months of therapy approximately 80 per cent had levels below 40 ng. per 100 ml. High levels of plasma testosterone were associated with significant prolongation of the follicular phase of the cycle and increased incidence of amenorrhea or anovulation. An over-all pregnancy rate of 50.4 per cent resulted from the treatment. A direct relationship between pregnancy rates and sperm density as well as between pregnancy rates and degree of suppression of plasma testosterone after therapy was observed. These results demonstrate a high incidence of hyperandrogenism in female partners of infertile couples. The effectiveness of glucocorticoid treatment appears to be related to suppression of excessive androgen levels. The data also suggest that infertility is a relative state related to the fertility potential of each member of the couple. Improvement of the fertility potential of either member may result in conception.

Amenorrhea↗
PubMed1979

Hormone interactions in the Sertoli cells.

The effects of follicle-stimulating hormone (FSH) and testosterone in rat Sertoli cells were investigated in vitro by means of isolated cell populations. The Sertoli cells selectively bind FSH, and respond to FSH stimulation with increased accumulation of endogenous cyclic AMP and secretion of androgen-binding protein (ABP). FSH binding and cyclic AMP response in the Sertoli cells change dramatically during sexual maturation. Cyclic AMP response decreases despite an increase in FSH-binding receptors per cell. Evidence has been provided for the existence of cytoplasmic and nuclear androgen receptors and chromatin acceptor-sites that specifically bind the androgen-receptor complex in the Sertoli cells. A model has been proposed for the hormonal interactions in the seminiferous tubule and the possible role of Sertoli cells in mediating the hormonal effects on spermatogenesis.

Animals↗