Biomedical subjects

S B Fishel

Publications and source records attributed to S B Fishel.

30 records · Page 2Linked to original sources

PubMed1984

The application of the zona-free hamster egg test for the prognosis of human in vitro fertilization.

The zona-free hamster egg test was carried out using spermatozoa from 15 men which consistently failed to fertilize their wives' oocytes in vitro. Spermatozoa from nine of these men fertilized hamster eggs in vitro, indicating that positive results in this assay are an unreliable guide to human in vitro fertilization. Donor spermatozoa were needed to fertilize the wife's oocytes in three of these cases. Nevertheless, the proportion of hamster egg penetration was significantly lower compared with spermatozoa from 15 men who could fertilize their wives' oocytes in vitro. The hamster assay also failed to indicate the establishment of pregnancy.

Adult↗

PubMed1984

Morphology and X-ray microprobe analysis of spermatozoa from fertile and infertile men in in vitro fertilization.

This paper reports differences observed in the elemental content of fertile and infertile human spermatozoa used in an in vitro fertilization (IVF) program. "Fertile" and "infertile" were designated by the successful penetration or failure to penetrate an oocyte in vitro. We report morphological and morphometric differences which, together with elemental changes, may be causes of infertility in apparently normal spermatozoa. There were significant differences (P less than 0.05) in sodium and chlorine concentrations between fertile and infertile samples and there was more chlorine than could be accounted for as sodium chloride. Many spermatozoa showed particles adhering to tails, with a higher incidence of "contamination" in the infertile spermatozoa. There were significant differences in both shapes of heads and lengths of tails between fertile and infertile spermatozoa.

Chlorine↗

PubMed1984

Analysis of 25 infertile patients treated consecutively by in vitro fertilization at Bourn Hall.

Twenty-five infertile women suffering from tubal disorders were treated consecutively by in vitro fertilization over a 14-day period. Follicular growth in 24 of them was stimulated with clomiphene citrate, ovulation being induced by an endogenous surge of luteinizing hormone or an injection of human chorionic gonadotropin. One patient was given tamoxifen and had an endogenous luteinizing hormone surge. One or more oocytes were fertilized, and at least one embryo was replaced in 19 patients. Nine pregnancies were established, and eight infants have been delivered, a pregnancy rate of 36% per laparoscopy and 47% per replacement. A detailed analysis of each patient is presented.

Adult↗

PubMed1983

Follicular steroids as a prognosticator of successful fertilization of human oocytes in vitro.

Oocytes were collected by aspiration of preovulatory follicles from 55 women. The preovulatory rise in LH was monitored in urine using the Hi-Gonavis (Mochida Pharmaceuticals) technique. Patients were treated either during the natural cycle or after the induction of ovulation with clomiphene citrate. After collection and culture, the oocytes were inseminated with the spermatozoa of the husband. The levels of progesterone, oestradiol-17 beta and androstenedione in the clear follicular fluid were measured by radioimmunoassay. A multivariate analysis containing these three hormone levels together with two ratios of progesterone with each of the other hormones indicated reasonable discrimination between the oocytes which fertilized and those which remained unfertilized after insemination. The discriminant analysis suggested that the fertilization of the oocytes could have been predicted on the basis of these hormonal profiles with a success rate which exceeded 90%.

Androstenedione↗

PubMed1981

Embryonic and uterine factors in delayed implantation in rodents.

An hypothesis for delayed implantation and embryonic quiescence is proposed on the basis of adaptation of blastocysts to changes in their environment. The environmental factors considered consist of macromolecules and essential ions and metabolites such as Ca2+, Mg2+ and glucose. Macromolecules appear to induce an influx of these essential metabolites which is followed by metabolic enhancement in blastocysts in the absence of any of the essential factors, the initial stages of embryonic diapause follow. The prevention of influx of metabolites such as Ca2+ by specific inhibitors, D600 or papaverine, also prevents activation of blastocysts. Early cleavage stage embryos show little or no response to changes in environmental macromolecules which may explain why embryos usually enter into quiescence at the blastocyst stage when the environmental constraints on blastocyst development become very marked. This also coincides with termination of cleavage and initiation of cell growth in embryos. The increase in responsiveness of embryos is attributed to several inherent changes including cell surface and functional changes in the plasma membrane. The conditions for embryonic quiescence in vivo are not species specific. Trophoblastic vesicles without the inner cell mass can also enter into quiescence. Studies using the antibiotic, tunicamycin, which inhibits protein glycosylation and prevents trophoblast adhesion and giant cell outgrowths, suggest that the cell surface interactions may involve glycoproteins. Such interactions may be crucial for implantation as well as for maintaining embryos in diapause for prolonged periods of time. A short sojourn in diapause for certain blastocysts which do not normally develop to an advanced stage, appears to have a beneficial effect on subsequent development. The overall significance of this suggestion for other species showing obligatory diapause is unclear.

Animals↗

PubMed1980

Evidence for the synthesis and release of a glycoprotein by mouse blastocysts.

Mouse blastocysts were incubated in microdrop cultures in the presence of D-[6-3H]glucosamine. The embryos and the incubation medium were analysed for the incorporation of label into acid-precipitable material. Of the precursor incorporated into blastocysts, 8-13% was detected in the medium. Several glycoproteins were found in the blastocysts and one of molecular weight about 87 000 was also detected in the extracellular medium. In the presence of tunicamycin, the amount of the labelled glycoprotein was reduced by 30-40% in the embryos and 47-69% in the medium. However, the same relative proportion of label was still detected in the extracellular fraction of 87 000 mol. wt. The study demonstrates the synthesis and release of a glycoprotein by mouse blastocysts, the mechanism of which is tunicamycin-insensitive.

Animals↗

PubMed1980

Radiolabelled uterine proteins during early pregnancy and pseudopregnancy in mice after unilateral ovariectomy and superovulation.

Uterine secretions were analysed after labelling in vivo with L-[4,5-3H]leucine. The acid-precipitable counts were highest on Day 1 p.c., low on Day 2, lowest on Day 3, and similar to Day 2 values on Day 4 p.c. After unilateral ovariectomy the acid-precipitable counts for the horn ((+)ovary) ipsilateral to the remaining ovary were higher than those in the contralateral horn ((-)ovary) for each condition studied. Superovulation yielded slightly higher acid-precipitable counts in the (-)ovary and (+)ovary horns of pregnant mice on Day 3 p.c., and in the (+)ovary horn only for pseudopregnant mice on Day 2 p.c. The Day 2 counts for the (+)ovary and (-)ovary horns of the superovulating pseudopregnant mice were higher counts than those for superovulating pregnant mice, but the reverse occurred for (+)ovary horns only on Day 4 p.c. No qualitative differences between pseudopregnant and pregnant mice were observed on Day 4 and superovulation appeared to enhance the profiles obtained.

Animals↗

PubMed1980

The role of divalent cations in the metabolic response of mouse blastocysts to serum.

Uptake and incorporation of [3H]uridine by mouse blastocysts was measured in response to serum under various conditions of Ca2+ and Mg2+ availability. Previous studies (Fishel & Surani, 1978) showed that serum stimulated uptake and incorporation of uridine in blastocysts. Here it is shown that in Ca2+-deficient medium (< 20 microM-Ca2+) cell metabolism was also inhibited and increasing [Ca2+] resulted in increased uptake and incorporation. Maximum stimulation required an extracellular [Ca2+) of 0.25 mM. The effects of low Ca2+ were reversible and could also be alleviated by 15 and 20 mM-Mg2+. Magnesium greater than 20 mM was deleterious. Inorganic phosphate (Pi) was used to complex free Mg2+ in order to maximize the effects of Mg2+ deficiency. Inhibition was reversed by increasing [Mg2+] or by 15-20 mM-Ca2+. Calcium concentrations greater than 20 mM inhibited maximum stimulation. Inhibitors of Ca2+ influx D600 and papaverine, inhibited stimulation at concentrations above 5 and 20 microM respectively. Magnesium concentration of 15 mM alleviated the inhibitory effects of 50 microM D600. The effect of Ca2+-deficient medium was also alleviated by Sr2+. The results suggest that both Ca2+ and Mg2+ are required for blastocysts to respond maximally to serum; their initial role appeared to involve the binding of stimulatory serum molecules to the cells of the blastocyst followed by an influx of these cations.

Animals↗

PubMed1979

Analysis of mouse uterine proteins at pro-oestrus, during early pregnancy and after administration of exogenous steroids.

Uterine secretions were analysed after labelling with L-14,5-3H]leucine. During pro-oestrus major protein peaks were seen with approximate mol. wt 2.0 X 10(4), 2.7 X 10(4), 4.0 X 10(4), 5.7 X 10(4), 7.8 X 10(4) and 13.0 X 10(4). Qualitative changes were observed during the first 4 days of pregnancy. On day 4 p.c. secretions revealed two prominent peaks with mol. wt 6.7 X 10(4) and 12.5 X 10(4), four peaks between 2.0 and 4.7 X 10(4) and one at 8.5 X 10(4) and one at 20.0 X 10(4). Profiles similar to those on mimic Day 4 p.c., and implantation, were induced in ovariectomized females by administration of exogenous progesterone and oestradiol, whereas the proteins detected after administration of exogenous oestradiol alone were essentially similar to those found at pro-oestrus. Ovariectomized mice treated with the steroid sequence to mimic Day 4 p.c. profiles but not given the final injection of oestradiol showed no detectable labelled proteins. Injection of progesterone or oestradiol alone, in the final sequence of injections given to ovariectomized pregnant females treated with progesterone, did not induce blastocyst implantation. These studies indicate a synergistic relationship between progesterone and oestrogen in the secretion of uterine macromolecules.

Animals↗

PubMed1978

Changes in responsiveness of preimplantation mouse embryos to serum.

Changes in uptake of radioactive uridine and its incorporation into RNA were determined in preimplantation mouse embryos, from the 2-cell to the blastocyst stage, as a measure of their responsiveness to extracellular conditions. Two media were tested, one contained serum and the other contained bovine serum albumen as a control. An increase in the acid-soluble pool occurred at the 8-cell stage and a marked increase in RNA synthesis occurred at the early blastocyst stage when the embryos were incubated with serum.

Animals↗

PubMedDate not supplied

Oocyte maturation and fertilization in vitro.

From the time of early follicular growth to some time after ovulation, the oocyte undergoes many critical changes in its biochemistry. In this paper the author describes different steps in oocytes maturation some of which, during the early period, will require support from the follicle cells, while later in development endogenous synthetic activity can be maintained in the absence of such support.

Animals↗

PubMedDate not supplied

Treatment of male infertility by in vitro fertilization: factors affecting fertilization and pregnancy.

IVF was attempted in more than 100 couples where the man was considered to be the cause of the infertility. 57% of all oocytes were fertilized and embryo replacement was achieved in 60-70% of cases. Pregnancies following IVF were established in cases with a long duration of infertility and different male factors such as oligospermia, teratospermia, asthenospermia and auto-immunity. Almost 50% of men with very low numbers of active spermatozoa (0.5 X 10(6)/ml motile spermatozoa) were able to establish pregnancy. No correlation was found between the percentage motility and the chance of fertilization in cases with abnormal semen, but a reduction of the incidence of fertilization was noticed in cases with extreme oligospermia (5 X 10(6)/ml) where 41% of the oocytes were fertilized. The results of the post coital hamster egg tests were inaccurate in predicting the outcome of IVF. The collection of split ejaculates, and the careful preparation of spermatozoa using sedimentation and layering methods proved to be beneficial, improving sperm motility and raising the chance of fertilization.

Embryo Transfer↗