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Biomedical subjects

R Z Sokol

Publications and source records attributed to R Z Sokol.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effect of abstinence on sperm motility in normal men.

We investigated the effect of varying the length of ejaculatory abstinence on sperm motility by a method of automated videomicrography. Ten fertile donors to an artificial insemination clinic provided semen samples at randomly assigned intervals of 12, 24, 72, and 120 hours. All specimens were produced on site, immediately incubated at 37 degrees C, and processed in triplicate. In comparing ejaculates obtained after 12 hours' abstinence with those after 120 hours, semen volume and sperm concentration demonstrated a significant increase with increasing abstinence time (p = 0.03). However, no correlation between abstinence time and percentage of motility, lateral head amplitude, cross-beat frequency, mean velocity, and mean linearity was found. We conclude that motility does not change with ejaculatory frequency and that in normal men prescribed abstinence before analysis of semen for motility characterization may not be necessary.

Humans↗
PubMed1988

Endocrine evaluation in the assessment of male reproductive hazards.

Male reproductive function requires the integrated functioning of the hypothalamus, pituitary, and testis. The disturbance of endocrine function at any of these levels may result in hypogonadism and infertility. The clinical and laboratory evaluation of these disorders is reviewed here.

Endocrine Glands↗
PubMed1988

A controlled comparison of the efficacy of clomiphene citrate in male infertility.

To determine whether clomiphene citrate (CC) improves fertility in oligospermic men, 23 men with sperm concentrations between 0.5 and 20 million sperm per milliliter; normal serum gonadotropins and testosterone; and a presumptively fertile partner were enrolled in the study. After a 3-month control period, patients were randomly prescribed CC, 25 mg/day; or placebo, 1 tablet/day, for 12 months. The pregnancy rates for the CC group and the placebo group were 9.09% and 44.44%, respectively (not significant). During the treatment phase, the CC group had significantly higher levels of luteinizing hormone (LH) serum, follicle-stimulating hormone (FSH), testosterone (T), and estradiol than the placebo group. CC treatment also resulted in greater LH, FSH, and T responses to gonadotropin-releasing hormone (GnRH). There were no differences between the placebo and CC groups for the sperm penetration assay or semen parameters. The authors conclude that CC is not a useful drug in the treatment of male infertility.

Clomiphene↗
PubMed1987

Hormonal effects of lead acetate in the male rat: mechanism of action.

Environmental exposure to toxic levels of lead occurs in a number of industries with potential adverse effects on the reproductive capacity of exposed men. Using a rat model, we previously reported that dietary exposure to lead resulted in suppressed spermatogenesis and testosterone levels without significant changes in luteinizing hormone (LH). In this study, to identify more specifically the site of lead's toxic actions on the hypothalamic-pituitary-testicular axis, the response of lead-treated male rats as compared to control animals to naloxone, gonadotropin-releasing hormone (GnRH), and LH stimulation was studied. Three groups of 52-day-old Wistar rats were allowed access to either deionized distilled water containing no lead acetate or a 0.3% lead acetate solution for 30 days. In each study group, 10 control and 10 lead-treated animals were anesthetized prior to cardiac puncture and collection of serum for the measurement of lead level and baseline LH (Groups I and II) or testosterone levels (Group III). In Group I, 20 min after an i.p. injection of naloxone (1.5 mg/kg/BW), the animals were killed by decapitation, and serum was collected for LH measurement. Thirty minutes after an i.p. injection of GnRH (100 ng/100 gm BW), Group II animals were killed by decapitation, and serum was collected for LH. Sixty minutes after an injection of LH (100 mg/100 mg BW), serum was collected from Group III animals for testosterone measurement. All control animals and lead-treated animals consumed similar volumes of water. Control animals had undetectable levels of lead in their blood. Lead-treated animals had mean blood lead values of 30 micrograms/dl +/- 5 micrograms/dl.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Demonstrated paternity in spite of severe idiopathic oligospermia.

In this study we report on a successful pregnancy in the spouse of a man who, on repeated occasions, spaced over 3 years, presented with a mean sperm concentration of less than 200,000 sperm/ml. Serum was drawn from the father, mother, and daughter for polymorphic gene marker analysis. The calculation of relative probability of paternity with the use of gene frequencies for whites gave a figure of 99.9% that our patient is the father of the child.

Adult↗
PubMed1986

Serum and semen zinc levels in normozoospermic and oligozoospermic men.

Zinc is necessary for growth, sexual maturation and reproduction. Because high concentrations of zinc are found in the male reproductive system, a relationship between zinc and male infertility has been suggested. We studied 11 unselected men who presented to a Reproductive Endocrinology Clinic with histories of infertility and low sperm counts. Reproductive hormones and semen and serum zinc levels were measured. All men had semen analyses performed on at least three separate occasions. A similar set of laboratory evaluations were performed on 11 other men who had normal semen analyses and no history of infertility. No abnormalities of reproductive hormones were found in either group. Mean serum zinc levels were significantly lower in the infertile men (p less than 0.05). Mean semen zinc levels were not significantly different. There was no correlation between serum and semen zinc levels in either group. A significant correlation was found between sperm count and semen zinc (r = 0.66, p less than 0.05) in the volunteers with normal counts, but not in the oligozoospermic men. The results obtained in this study suggest that lowered serum zinc is more common than formerly appreciated in unselected patients with infertility. The high level of zinc found in semen is due primarily to the secretions of the prostate gland and reflects prostatic stores. Serum zinc is thought to be a reasonable indicator of zinc status. The lack of correlation between serum zinc and semen zinc found in our study suggests that mild zinc deficiency may lower serum zinc while the larger prostatic zinc stores remain unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Identification and partial characterization of gonadotropin-releasing hormone-like factors in human seminal plasma.

Gonadotropin-releasing hormone (GnRH)-like material was measured by radioimmunoassay in acid-ethanol-extracted human seminal plasma using radiolabeled D-[Leu6] GnRH ethylamide as labeled ligand, authentic GnRH as standard, and antibody raised against D-[Lys6] GnRH analog. The mean amount of GnRH-like material measured in the seminal plasma of semen samples with sperm counts greater than 20 X 10(6)/ml was 229.0 +/- 66 pg/ml, with sperm counts less than 20 X 10(6)/ml was 213 +/- 42 pg/ml, and from vasectomized samples was 252 +/- 36 pg/ml. There was no significant difference among the three groups. Scatchard analysis of radioreceptor binding data demonstrated significant displacement of GnRH agonist ligand from castrated male rat pituitary membrane preparations. Ultrafiltration and gel column chromatography of pooled extracted seminal plasma identified two compounds with apparent molecular weights of 2600 and 5000 that differ chemically and immunologically from native GnRH. Further characterization using affinity column chromatography suggests that at least one of these GnRH-like factors is a glycosylated protein.

Chromatography, Gel↗
PubMed1985

Lead toxicity and the hypothalamic-pituitary-testicular axis.

Environmental exposure to toxic levels of lead occurs in a number of industries with potential adverse effects on the reproductive capacity of exposed men. Clinical and animal studies indicate that abnormalities of spermatogenesis result from toxic lead exposure, but the pathogenetic mechanisms involved have not been identified. In order to ascertain what reproductive abnormalities occur in experimental animals when exposed to low levels of lead, 52-day-old animals were treated with water containing 0.0% (control), 0.1%, or 0.3% lead acetate for 30 days prior to killing. Whole blood serum lead levels were below detection (less than 7 micrograms/dl) in the control animals, 34 +/- 3 micrograms/dl in the 0.1% group, and 60 +/- 4 micrograms/dl in the 0.3% group (P less than 0.001). Significant negative correlations between whole blood lead levels and serum and intratesticular testosterone values were found (r = 0.64, P less than 0.001 and r = 0.6, P less than 0.001, respectively). As the level of lead exposure increased, intratesticular sperm counts significantly decreased (r = 0.81, P less than 0.001). No significant changes in serum luteinizing hormone (LH) values were found, but sperm follicle-stimulating hormone (FSH) values were significantly suppressed (P less than 0.05) after lead treatment. There was a significant decrease in ventral prostate weight (P less than 0.05), but no differences in testicular or seminal vesicle weights. Our data indicate that dietary exposure to lead resulting in whole blood serum lead values considered acceptable in the workplace (less than or equal to 40 micrograms/dl) causes inhibition of testicular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

UCLA conference. Infertility in the male.

Male infertility is a common and distressing problem in which reproductive abnormalities frequently play an important role. Assessment requires an understanding of the control of spermatogenesis and factors responsible for normal sperm function. Standard tests for assessment of semen quality frequently fail to detect impaired function, but newer tests are now available to measure sperm movement and their ability to penetrate the ovum. Algorithmic approaches based on laboratory data can be used to characterize subgroups of infertile men, but many patients have subtle abnormalities. Treatment of male infertility is ideally directed to a specific pathogenic mechanism; nonspecific therapies have produced disappointing results. Surgery is indicated for certain types of ductal obstruction, but whether internal spermatic vein ligation should be used to treat varicocele remains uncertain.

Acrosome↗
PubMed1982

Comparison of the kinetics of injectable testosterone in eugonadal and hypogonadal men.

Serum reproductive hormone levels were measured serially after eugonadal and hypogonadal men had received either a 200-mg or a 100-mg intramuscular injection of testosterone enanthate. The calculated mean integrated testosterone and estradiol levels indicated that the 200-mg testosterone enanthate injection in the hypogonadal subjects maintained eugonadal levels of these hormones through day 11. The 100-mg dose maintained eugonadal levels of these hormones through day 11. The 100-mg dose maintained eugonadal testosterone levels through day 7. The testosterone:estradiol ratios in both groups following the 200-mg injection remained above or at the eugonadal baseline trough day 21. The authors recommend that replacement therapy for hypogonadal men should be 200 mg of testosterone enanthate every 10 to 14 days. A similar dosage would be recommended if testosterone enanthate were to be used as an experimental inhibitor of spermatogenesis (contraceptive agent).

Adolescent↗
PubMed1981

Gonadotropin therapy failure secondary to human chorionic gonadotropin-induced antibodies.

A 15-yr-old male with the diagnosis of Kallmann's syndrome manifested secondary gonadal resistance during a third treatment course of hCG. A serum sample obtained 6 months after failure of the patient to respond to hCG bound [125I]hCG 60% at a 1:2 dilution of serum; 50% at 1.5; 28% at 1:50; 21% at 1:100; and less than 5% at a 1:500 dilution. Serial sampling of the patient's serum over a 22-month period demonstrated a progressive decline in binding capacity, decreasing to 32% binding of [125I]hCG at a 1:2 dilution of serum. The data demonstrated that the patient produced a low affinity, high capacity binding substance with a Ka of 5 x 10(7) liters/M and a R0 of 1.8 x 10(16) sites/g gamma-globulin. The binding substance appeared to be a gamma-globulin of the immunoglobulin G class, which bound labeled hCG and human LH (hLH) more avidly than it bound hFSH and interfered with the biological response to hCG therapy. These data further indicated that antibodies produced against hCG may bind other endogenous glycoproteins such as hLH, hFSH, and hTSH. Although binding to hTSH did not occur in this patient, the presence of a common beta-chain in the molecular structures of hLH, hFSH, hCG, and TSH makes such a potential occurrence not implausible. Despite the apparent infrequency of the development of clinically observable interference with the biological activity of hLH/hCG in hCG-treated patients, this report indicates that a potential hazard exists. The possibility should be considered in the decision to treat a patient with normal gonadotropin secretion with exogenous gonadotropins.

Adolescent↗
PubMedDate not supplied

Comparison of two weeks versus one week of prenatal ethanol exposure in the rat on gonadal organ weights, sperm count, and onset of puberty.

Sprague-Dawley dams from Harlan Ind. (Indianapolis, IN) were administered a fortified ethanol liquid diet containing 35% ethanol derived calories for two weeks (E-2) beginning on day 7 or one week (E-1) beginning on day 13 of gestation and continuing through parturition. Control dams were pair-fed an isocaloric liquid diet containing no ethanol during these periods or remained on lab chow and water. E-2 dams consumed an average of 13.52 g ethanol/kg bwt during the first week of exposure (days 8-14) and 12.50 g ethanol/kg bwt the second week (days 14-20). E-1 dams consumed significantly less than E-2 dams during the second week (9.75 g/kg; p < 0.0001). Although the lower consumption in E-1 dams led to a significant decrease in maternal weight gained during the few days of pregnancy compared to E-2 dams, birthweights of E-1 offspring were significantly heavier than those of E-2 offspring (p < 0.05). No effect of ethanol was detected on anogenital distance at birth in either sex. Puberty was delayed in female offspring of both E-1 and E-2 dams (p < 0.01) as measured by age of vaginal opening. These data suggest that the primary teratogenic actions of ethanol in the rat on fetal growth, as well as delayed puberty in females, occur in the last week of gestation. In adult E-2 males, testis weight was significantly heavier than all other groups when indexed to body weight. No effect of prenatal ethanol exposure was observed on the indexed weights of prostate, epididymis, or seminal vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcoholism↗
PubMedDate not supplied

Effects of lead exposure on GnRH and LH secretion in male rats: response to castration and alpha-methyl-p-tyrosine (AMPT) challenge.

Animal and clinical studies suggest that lead exposure disrupts the hypothalamic-pituitary axis. To define more precisely the toxic action of lead on the hypothalamic-pituitary unit, a series of in vivo and in vitro experiments were performed. The first experiment was designed to determine whether lead exposure exerts an inhibitory effect on GnRH secretion as reflected by an enhanced inhibition of luteinizing hormone (LH) secretion in response to the tyrosine hydroxylase inhibitor methyl-p-tyrosine (AMPT). In the control animals, the AMPT dose had no significant effect on LH secretion, whereas LH fell significantly in the lead-treated animals. In experiments designed to evaluate the effects of lead exposure on the pattern of pulsatile release of gonadotropins castrated control and lead-dosed animals were cannulated, and serial blood sampling was performed. Baseline LH and follicle-stimulating hormone values were not statistically different between the control and lead-treated group. There were no significant differences noted in pulsatile patterns when the data were analyzed as groups. Pituitary cells harvested from lead-treated animals released significantly more LH that did the control animals. These data are consistent with the hypothesis that the signals between the hypothalamus and pituitary gland are disrupted by lead exposure in the intact animal. However, the lead-exposed castrated rat's hypothalamic-pituitary unit is able to adapt to the toxic effects of lead.

Adaptation, Physiological↗
PubMedDate not supplied

The split ejaculate: assessment of fertility potential using two in vitro test systems.

Semen samples (split & whole ejaculates) were obtained from 12 normal men (group A) and 8 oligospermic infertile men with sperm concentrations of less than 20 x 10(6) sperm/ml (group B). All samples were evaluated by standard semen analysis, bovine cervical mucus penetration assay (CMPT), and, in all cases with sufficient sperm, in the human spermatozoa zona-free hamster in vitro penetration assay (SPA). In group A the motile sperm concentration was significantly higher in the ejaculated material of the first two contractions (fraction I or FI) than in the remainder of the ejaculate (fraction II or FII) (p less than 0.02). No significant differences were observed in sperm penetration into zona-free hamster ova or bovine cervical mucus by sperm from FI, FII or the whole ejaculate. Motile sperm concentration was significantly correlated with sperm penetration into bovine cervical mucus (r = 0.65, p less than 0.01), but not into zona-free hamster ova (r = 0.01 NS). In the samples collected by group B, the mean sperm concentration and motile sperm concentration were higher in the first (FI) than in the second (FII) fractions of the split ejaculate or the whole ejaculate (p less than 0.05). No significant differences were found among the FI, FII and the whole ejaculate semen samples for penetration of sperm into bovine cervical mucus. Sperm concentration and motile sperm concentration were significantly correlated with sperm penetration into bovine cervical mucus (r = 0.58, p less than 0.01 and r = 0.57, p less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Cervix Mucus↗