Biomedical subjects

A N Beltsos

Publications and source records attributed to A N Beltsos.

3 recordsLinked to original sources

PubMed1999

Abnormal estrous cyclicity after disruption of endothelial and inducible nitric oxide synthase in mice.

The roles of nitric oxide (NO) and nitric oxide synthase (NOS) in reproduction were studied by examining the estrous cycle of wild-type (WT) mice, inducible NOS (iNOS)-, and endothelial NOS (eNOS)-knockout mice. We observed an average estrous cycle of 4.8 +/- 0.2 days in WT mice. While we observed no significant influence of iNOS deficiency on cycle length, eNOS-knockout females showed a significantly longer estrous cycle (6.6 +/- 0.6 days; p < 0.03) than WT females, due to an extension of diestrus (p < 0.03). There was no influence of iNOS deficiency on ovulation rate compared with that in WT females; however, eNOS-knockout mice showed a significant reduction (p < 0.05) in ovulatory efficiency relative to WT or iNOS-knockout females. In contrast to WT females, in which the highest level of estradiol (E2) was observed at 1500 h of proestrus, iNOS-knockout females reached a peak of E2 at 1830 h of proestrus. In eNOS-knockout females, the peak of E2 occurred at 1830 h, as in iNOS-knockout mice; however, E2 levels were 5-fold and 3-fold higher (p < 0.05) than levels observed in WT and iNOS-knockout females, respectively. There was no effect of genotype on the plasma LH concentrations at proestrus. On the first day of diestrus, eNOS-knockout females showed significantly higher plasma E2 and progesterone levels (p < 0.05) relative to WT and iNOS-knockout females. The dysfunction in cyclicity, ovulation rate, ovarian morphology, and steroidogenesis in eNOS-knockout female mice strongly supports the concept that eNOS/NO plays critical roles in ovulation and follicular development.

Animals↗

PubMed1996

Ovulation induction and ovarian malignancy.

Many couples faced with infertility are treated with ovulation inducing medicines. Recently, concerns have been raised about the possible risk of ovarian malignancy after such ovarian stimulation. Theories of pathogenesis for ovarian cancer include incessant ovulation, elevated pituitary gonadotropins, genetic predisposition, and chemical carcinogens. Protective factors include suppression of ovulation, pregnancy, and castration. Low numbers of exposed women who develop ovarian cancer make this a difficult research subject. Research to date demonstrates conflicting results, with some investigators reporting an increased risk of ovarian cancer with fertility drugs, whereas others do not. The likely magnitude of risk, if one believes a risk exists, may be two to three times that of the general population which is at most 4-5% in a woman's lifetime. The present uncertainty makes it challenging to apply this to today's practice of medicine. With continued efforts worldwide, we hope an understanding of this will be forthcoming.

Female↗

PubMedDate not supplied

The relationship of the postcoital test and semen characteristics to pregnancy rates in 200 presumed fertile couples.

OBJECTIVE: To evaluate the postcoital test (PCT) and semen analysis (SA) in the prediction of pregnancy in 200 potentially fertile couples. METHODS: 200 couples without risk for infertility were prospectively followed for 1 year. Couples were attempting pregnancy for 12 menstrual cycles. In the first three cycles, the women underwent monthly PCTs and collected daily urines while the men provided bimonthly semen analyses. For the next nine cycles, the couples were monitored for pregnancy. The PCT included hours post-coitus, amount of mucus, spinnbarkeit, number of motile sperm, and percent of motile sperm. Since multiple PCTs and SAs were available for each couple, values were averaged to provide one mean value per couple. The Wilcoxon ranked sum test was used to detect differences in PCT and SA. RESULTS: Pregnancy occurred in 163/200 couples (82%) in 12 cycles. Mean sperm count per high-power field (p = 0.01) and mean number of highly motile sperm (p = 0.03) were higher among women in whom pregnancy occurred. Amount of mucus and spinnbarkeit were similar between women who became pregnant and those who did not. Semen concentration, motile sperm count, and percent motile sperm were significantly higher among men whose partner conceived (P < .02). Only 93 couples (47%) had PCTs that were correctly timed. CONCLUSIONS: Measures predictive of pregnancy included vigorously moving sperm per high-power field, sperm concentration, motile sperm count, and percent motility. Mucus characteristics were not predictive of pregnancy. Additionally, a high number of sperm seen in the PCT correlated with a high number of motile sperm in the SA. These results support the use of the PCT for initial evaluation of the infertile couple.

Adult↗