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Biomedical subjects

S Daya

Publications and source records attributed to S Daya.

At least 73 records · Page 4Linked to original sources
PubMed1996

Polyploidy and failed fertilization in in-vitro fertilization are related to patient's age and gamete quality.

A review of 392 cycles of in-vitro fertilization (IVF) was carried out in order to identify whether any factors such as sperm concentration at insemination, sperm motility or morphology, oocyte grading, number of oocytes retrieved, patient age, follicular stimulation protocols or duration of follicular growth, could be associated with the incidence of polyploidy or completely failed fertilization. The majority of polypronuclear fertilizations occurred in mature oocytes and in patients < 37 years of age and the incidence of polyploidy was strongly associated with fertilization and pregnancy rates. Fertilization rates were highest with mature oocytes. A significant linear trend was observed with failed fertilization and sperm concentration, morphology and motility. High rates of failed fertilization were found in patients > 37 years of age and with one to five oocytes retrieved. No significant difference was seen in stimulation protocols and oocyte grading between oocytes that fertilized and those that did not. Cycles with good sperm morphology and motility, the presence of mature oocytes, the retrieval of a large number of oocytes and younger maternal age seem to provide the best chance for IVF success.

Adult↗
PubMed1996

Evaluation and management of recurrent spontaneous abortion.

Recurrent spontaneous abortion is a frustrating problem for clinicians and their patients. Fortunately, a reasonable amount of research is being conducted to try and identify the causes of this disorder and develop appropriate and effective diagnostic tests and therapies. This review focuses on some of the factors that have been associated with recurrent abortion, such as cell-mediated immune responses to trophoblast antigens, the effect of oxidative stress, and the immunomodulatory properties of placental protein. The risk of recurrence is particularly high when the length of the embryo in early pregnancy is less than the 50th centile, even though cardiac activity may be present. Also, the risk is directly related to the number of previous abortions. Efficacy has been shown for treatment of unexplained recurrent abortion with allogeneic leukocyte immunization and possibly with intravenous immunoglobulin. Patients with oligomenorrhoea may benefit from treatment with human chorionic gonadotropin.

Abortion, Spontaneous↗
PubMed1995

Melatonin and steroids in human pre-ovulatory follicular fluid: seasonal variations and granulosa cell steroid production.

Follicular fluid samples were obtained from the largest pre-ovulatory follicle of 120 women undergoing in-vitro fertilization and were examined for melatonin by enzyme-linked immunosorbent assay and the steroids oestradiol and progesterone by radioimmunoassay. The concentrations (mean +/- SE) of melatonin (213.4 +/- 18.9 pmol/l) and progesterone (20.1 +/- 1.1 mumol/l) in follicular fluid during the autumn and winter (dark) months were significantly higher than during the spring and summer (light) months, melatonin (138.4 +/- 12.5 pmol/l) and progesterone (11.6 +/- 0.8 mumol/l). By contrast, oestradiol concentrations were significantly lower during the dark months than during the light months (264.7 +/- 44.1 and 661.8 +/- 55.1 nmol/l respectively). There was a positive correlation between follicular fluid melatonin and progesterone concentrations (r = 0.271, P < 0.05, n = 120) and a negative relationship between melatonin and oestradiol (r = -0.254, P < 0.05, n = 120). The effects of melatonin alone and in combination with human chorionic gonadotrophin (HCG) or follicle stimulating hormone (FSH) on steroidogenesis by human granulosa cell culture were also investigated. Melatonin had minimal effects on oestradiol or progesterone production by granulosa cells. Interestingly, the oestradiol response in culture appeared to be different according to the time of the year when harvested. During the light period oestradiol production was enhanced. Melatonin also synergized with HCG in increasing progesterone production on days 6 and 7 after treatment during both light and dark periods. FSH stimulated oestradiol production by the cells on day 2 of culture. Melatonin had no effect on FSH stimulation of oestradiol production. The results of this study suggest that melatonin may be involved in the regulation of steroidogenesis by the human ovaries.

Cells, Cultured↗
PubMed1995

Randomized controlled trial of follicle stimulating hormone versus human menopausal gonadotrophin in in-vitro fertilization.

The adverse effect of raised luteinizing hormone (LH) concentrations on reproductive outcome suggests that exogenous LH administration for ovarian stimulation may not be desirable. The aim of this study was to compare the clinical pregnancy rates between follicle stimulating hormone (FSH) and human menopausal gonadotrophin (HMG) used in in-vitro fertilization (IVF) cycles. A total of 232 infertile patients, with a mean duration of infertility of 67.1 +/- 32.9 months, were selected for IVF (female age < 38 years, FSH < 15 IU/l, and total motile sperm count > 5 x 10(6)). A short (flare-up) protocol with daily leuprolide acetate was followed randomly from day 3 with FSH (n = 115) or human menopausal gonadotrophin (HMG; n = 117), at an initial dose of two ampoules per day. A maximum of three embryos was transferred, and the luteal phase was supported with four doses of HCG (2500 IU). No differences were observed between the two groups in any of the cycle response variables except fertilization rates per oocyte and per patient, both of which were significantly higher with FSH. Clinical pregnancy rates per cycle initiated, per oocyte retrieval and per embryo transfer were 19.1, 21.0 and 22.7% respectively for FSH, and 12.0, 12.8 and 15.4% respectively for HMG. Whilst these differences were not statistically significant, the results of this interim analysis suggest that HMG may be associated with a lower clinical pregnancy rate than FSH.

Androgens↗
PubMed1995

Natural cycles for in-vitro fertilization: cost-effectiveness analysis and factors influencing outcome.

Improvements in oocyte culture technique, sperm preparation, oocyte retrieval method and ovarian stimulation regimens have produced higher pregnancy rates with in-vitro fertilization (IVF) treatment. However, because ovarian stimulation is expensive and not without risk, there is increasing interest in the option of using natural cycles for IVF. This study was performed to document the experience and outcome in 240 natural cycles. Cancellation occurred in 28 cycles (12%), and LH surge was observed in 56 (23%), leaving 156 (65%) cycles which progressed to oocyte retrieval. No oocytes were retrieved in 26 cycles. Among the successful oocyte retrievals, the majority yielded one oocyte. There was no evidence of fertilization in 26 cases, and triploid fertilization was observed in 12 cases. Embryos suitable for transfer were available in 92 cycles in which 11 (12%) clinical pregnancies were confirmed. Despite the high failure rate at each step in the process, natural cycles are more cost-effective than stimulated cycles which incur an incremental cost per live birth of $48,000. Natural cycles offer a low-cost alternative that may be more accessible to patients.

Adult↗
PubMed1995

A subset of patients with recurrent spontaneous abortion is deficient in transforming growth factor beta-2-producing "suppressor cells" in uterine tissue near the placental attachment site.

PROBLEM: To determine if patients with unexplained recurrent miscarriage have a deficiency of decidual immunosuppressor cells that produce transforming growth factor beta type 2, as has been found in mice with abortion due to rejection and/or trophoblast failure. METHODS: Decidual biopsy specimens were taken as near to the placental attachment site as possible under ultrasound guidance from first trimester legal termination (control) patients with recurrent miscarriage and non-viable pregnancy, and from patients with sporadic missed abortion. The tissue was tested for TGF beta-2+ suppressor cells by in situ hybridization, immunohistochemistry, and analysis of supernatants. RESULTS: TGF beta-2-related suppressor molecules similar but not identical to those identified in pregnant mice were released by decidual lymphoid cells. Fifty percent of 14 recurrent miscarriage patients showed a lack of suppressor cells and 59% were subnormal in comparison to 20 controls and 5 sporadic miscarriage patients, where 80-85% of the patients had detectable suppressor cells. CONCLUSIONS: Suppressor cell deficiency is compatible with a role for rejection and/or trophoblast failure in some patients with recurrent miscarriage. Presence of suppressor cells in most patients with missed abortion (4/5) is compatible with an alternative cause of fetal death, similar to findings reported in genetic fetal death mice.

Abortion, Habitual↗
PubMed1995

Follicle-stimulating hormone versus human menopausal gonadotropin for in vitro fertilization: results of a meta-analysis.

The observation of adverse effects of high-follicular-phase LH levels on fertilization, cleavage, embryo quality and pregnancy suggests that exogenous LH administration for ovarian stimulation in IVF may also be detrimental. The purpose of this study was to compare the use of FSH with hMG in IVF by conducting a systematic overview and meta-analysis of the evidence in the literature from randomized trials comparing the two gonadotropins. The data were extracted and pooled from eight studies that satisfied the inclusion criteria. The results show that FSH performs significantly better than hMG and is associated with at least 50% higher clinical pregnancy rates.

Evaluation Studies as Topic↗
PubMed1995

Protein ligand interactions. Part 5: Isoquinoline alkaloids as inhibitors of acetylcholinesterase from Electrophorus electricus.

Kinetic analysis has shown that papaverine, berberine and isoquinoline alkaloids acts as reversible competitive inhibitors of acetylcholinesterase with respect to the substrate, acetylthiocholine chloride. The inhibitor constants (Ki) vary from 3.5 microM to 88 microM. With time they act as irreversible covalent inhibitors with papaverine producing 85% inactivation after 40 min. Pseudo first-order kinetics are observed with the rate constant being proportional to the concentration of the ligand and the order of reaction being equal to one. Spectrophotometry was used to study the binding of the ligands with acetylcholinesterase and Scatchard analysis used to calculate the respective dissociation constants and the number of binding sites.

Acetylcholinesterase↗
PubMed1995

Follicle-stimulating hormone versus human menopausal gonadotropin for in vitro fertilization cycles: a meta-analysis.

OBJECTIVE: To conduct a systematic overview of available data comparing FSH with hMG in IVF treatment cycles. DESIGN: A meta-analysis of randomized trials of FSH versus hMG use in ovarian stimulation protocols, with or without GnRH agonists, in IVF treatment cycles. Search strategies included on-line searching of the National Library of Medicine MEDLINE data base from 1975 to 1993 and hand searching of bibliographies of relevant publications and reviews and abstracts of scientific meetings. Common odds ratio (OR) and overall absolute treatment effect were calculated after demonstrating homogeneity of treatment effect across all trials. MAIN OUTCOME MEASURES: Clinical pregnancy rates per cycle start, per cycle reaching oocyte retrieval, and per cycle reaching ET. RESULTS: Eight trials met the inclusion criteria. The overall OR in favor of FSH for cycle start, oocyte retrieval, and ET were 1.71, 1.69 and 1.70, respectively, and represented an overall absolute treatment effect of 8.5%, 8.0% and 8.3%, respectively. CONCLUSIONS: This meta-analysis demonstrates that in IVF cycles the use of FSH is associated with a significantly higher clinical pregnancy rate than hMG.

Abortion, Spontaneous↗
PubMed1995

[A randomized, controlled trial comparing follicle stimulating hormone (FSH) to human menopausal gonadotropin (hMG) in fertilization in vitro].

The adverse effect of raised luteinizing hormone (LH) concentrations on reproductive outcome suggests that exogenous LH administration for ovarian stimulation may not be desirable. The aim of this study was to compare the clinical pregnancy rates between follicle stimulating hormone (FSH) and human menopausal gonadotrophin (HMG) used in in-vitro fertilization (IVF) cycles. A total of 232 infertile patients, with a mean duration of infertility of 67.1 +/- 32.9 months, were selected for IVF (female age < 38 years, FSH < 15 IU/l, and total motile sperm count > 5 x 10(6). A short (flare-up) protocol with daily leuprolide acetate was followed randomly from day 3 with FSH (n = 115) or human menopausal gonadotrophin (HMG; n = 117), at an initial dose of two ampoules per day. A maximum of three embryos was transferred, and the luteal phase was supported with four doses of HCG (2,500 IU). No differences were observed between the two groups in any of the cycle response variables except fertilization rates per oocyte and per patient, both of which were significantly higher with FSH. Clinical pregnancy rates per cycle initiated, per oocyte retrieval and per embryo transfer were 19.1, 21.0 and 22.7% respectively for FSH, and 12.0, 12.8 and 15.4% respectively for HMG. Whilst these differences were not statistically significant, the results of this interim analysis suggest that HMG may be associated with a lower clinical pregnancy rate than FSH.

Adult↗
PubMed1994

The role of luteal phase support in infertility treatment: a meta-analysis of randomized trials.

OBJECTIVE: To determine whether the use of luteal phase support improves pregnancy rate (PR) in infertility. DESIGN: A meta-analysis of randomized trials of luteal phase support. Search of the National Library of Medicine MEDLINE data base from 1971 using the words luteal, pregnancy, human, and comparative. Bibliography of relevant articles, reviews, and abstracts of scientific meetings were hand searched. All randomized controlled trials of luteal phase support in infertility were included. Luteal phase support for recurrent abortion and nonrandomized trials were excluded. The common odds ratio was calculated for each intervention using the Mantel-Haentzel test. Homogeneity of treatment effect was evaluated using the Breslow-Day test. MAIN OUTCOME MEASURES: Pregnancy per cycle, rate of spontaneous abortion, and ovarian hyperstimulation syndrome rate. RESULTS: Eighteen trials met the above criteria. Human chorionic gonadotropin improved PRs in IVF when GnRH agonist (GnRH-a) was used (n = 151) and was superior to P (n = 352). Its benefit in all IVF cycles, however, was not established because of significant heterogeneity of treatment effect. Progesterone improved the PR in all IVF cycles (n = 457). No significant reduction in spontaneous abortion was noted with luteal support (n = 200). Ovarian hyperstimulation syndrome occurred in 5% of patients with hCG. Combination of data from trials of luteal support with other infertility therapies was not possible because of the differences in patient populations. CONCLUSIONS: The meta-analysis supports the routine use of hCG in IVF cycles using a GnRH-a. Progesterone was also beneficial for luteal phase support in IVF. For other infertility therapy, however, further research is needed to evaluate the role of luteal phase support.

Abortion, Spontaneous↗
PubMed1994

Cigarette smoking and the outcomes of in vitro fertilization: measurement of effect size and levels of action.

OBJECTIVE: To assess whether cigarette smoking in women or men affects the outcomes of IVF-ET and at what functional levels smoking is active. INTERVENTIONS: Demographic and smoking data were collected by questionnaire at the onset of consecutive treatment cycles (n = 462) and at the time of ET. In addition to routine endocrine and clinical data, circulating immunoreactive inhibin, follicular fluid E2 endometrial thickness, and morphology were assessed. Reported exposure to cigarettes was validated using a serum cotinine assay. RESULTS: Serum cotinine level at the onset of treatment correlated strongly with the number of cigarettes reported (r = 0.68). The duration and dose of gonadotropin treatment was greater among active smokers than never smokers: 10.2 versus 9.2 days and 24.7 versus 19.8 ampules, respectively. Fertilization, pregnancy, and abortion rates were similar between groups. Multivariate analyses demonstrated negative correlation between female age, but no such effect was seen with female or male smoking. Sperm concentration was significantly reduced in male smokers (prewash: 108 versus 130 x 10(6); postwash: 17.1 versus 21.6 x 10(6)), although fertilization rate was unaffected (66% versus 62%). Follicular function, assessed using serum inhibin and E2, as well as follicular fluid E2 levels showed no significant difference between active smokers and never smokers. Endometrial thickness and morphology also were similar between groups. CONCLUSIONS: These data suggest that among couples undergoing IVF neither female nor male smoking has a measurable deleterious effect on conception rate. Female age remains a far more potent prognostic factor in the current study. However, when all the published data are combined, a significant deleterious effect of smoking on conception is suggested, with a common odds ratio of 0.540 (95% confidence interval 0.385 to 0.757).

Adult↗
PubMed1994

Mode of inhibition of rat liver tryptophan 2,3-dioxygenase by melatonin.

Liver tryptophan 2,3-dioxygenase is a cytosolic enzyme that plays a crucial role in the regulation of circulating levels of tryptophan. Stimulation of the activity of this enzyme by heme enhances the catabolism of tryptophan, making less tryptophan available for uptake into the brain. Melatonin, the major hormone of the pineal gland, is shown to cause competitive inhibition of this enzyme (Ki = 2.70 microM). This structural analog of the substrate L-tryptophan is a negative homotropic cooperative modulator of the enzyme. The enzyme has a Km = 100 microM, and the substrate concentration required for optimum activity was found to be 2.5 mM with substrate inhibition becoming a feature at higher levels of tryptophan.

Animals↗
PubMed1994

The effectiveness of allogeneic leukocyte immunization in unexplained primary recurrent spontaneous abortion. Recurrent Miscarriage Immunotherapy Trialists Group.

PROBLEM: Unexplained primary recurrent spontaneous abortion (RSA) can be viewed as a partner-specific problem for which immunization with allogeneic leukocytes is being offered as therapy. Published data from randomized controlled trials have produced conflicting results regarding treatment effectiveness. The aim of this study was to perform a subgroup analysis of the data from a recent worldwide collaborative meta-analysis using the raw data for patients with primary RSA entered into randomized controlled trials of immunotherapy. METHODS: Data from randomized controlled trials in eight centers were included in this analysis. Individual patients were included only if they had had three or more spontaneous abortions, no previous pregnancy beyond 20 weeks' gestation, no identifiable cause for the abortions, and no evidence of antipaternal antibodies. Meta-analysis by centre and logistic regression analysis were performed to determine the overall effect of treatment in achieving live birth and to identify variables that affect the prognosis for a successful outcome. RESULTS: In the meta-analysis by center, immunotherapy significantly improved the live birth rate (common odds ratio = 1.94, 95% confidence interval (CI) = 1.20 to 3.12). In the analysis by patient, the likelihood of a successful outcome was also significantly better with treatment (relative risk = 1.46, 95% CI 1.19 to 1.69). The absolute treatment effect was 16.3% producing a number needed to treat of 6. The number of previous abortions had a significant negative correlation with live birth rate, such that for each additional pregnancy loss beyond three, the likelihood of live birth was reduced by 23%. CONCLUSION: Allogeneic leukocyte immunization is an effective treatment for unexplained primary RSA when pretreatment antipaternal antibodies are absent. Better diagnostic tests are required to identify patients who may derive maximal benefit from this therapeutic approach.

Abortion, Habitual↗
PubMed1994

Issues in the etiology of recurrent spontaneous abortion.

Recurrent spontaneous abortion is seen often. Although many causes of this condition have been identified, there is still a large proportion in which no cause can be found. This review highlights some of the newly described proposed causes. Several reports have linked reproductive inefficiency to hypersecretion of luteinizing hormone (LH) in the follicular phase. It is apparent that the presence of inappropriate elevation of LH, and not the ultrasonographic appearance of polycystic ovaries, is the critical factor in determining the risk of abortion. Consequently, by lowering the LH levels one can expect a better reproductive outcome. This hypothesis awaits testing through clinical trials. The role of ultrasonography in evaluating the luteal phase, by assessing the image of the endometrium, has been studied by many investigators. This non-invasive technique is not yet able to replace the endometrial biopsy. The association between antisperm antibodies in the female serum and recurrent spontaneous abortion requires re-evaluation in light of more recent evidence; however, the role of semen abnormalities, especially severe oligospermia in this disorder, points towards a factor in the male partner that should be identified. Oligomenorrhea has been identified by mathematical modeling as a potential risk factor for recurrent abortion, although the mechanism has not been clearly elucidated. Chromosome heteromorphisms, particularly inv (9)(p11 q12), appear to be associated, more frequently, with recurrent abortion. Similarly, associations were observed with factor-XII deficiency and high titers of immunoglobulin G (IgG) antibody to Chlamydia trachomatis.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Habitual↗