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Biomedical subjects

S Avery

Publications and source records attributed to S Avery.

At least 37 records · Page 2Linked to original sources
PubMed1998

Does ovarian hyperstimulation syndrome affect the quality of oocytes?

Two wives of a Muslim with severe male factor infertility had simultaneous intracytoplasmic sperm injection (ICSI) treatments. One wife developed ovarian hyperstimulation syndrome (OHSS), and 19 of 27 oocytes retrieved were subjected to ICSI but only one fertilized; the other wife had a normal response to ovarian stimulation, normal fertilization following ICSI, successful treatment and has recently delivered a live-born infant. The wife who suffered from OHSS has since had another ICSI cycle with a normal response to ovarian stimulation, a normal fertilization rate but no pregnancy. The only variable that determined the different rate of fertilization in the simultaneous ICSI cycles appears to be oocyte quality. While the results of frozen embryo replacement cycles following the decision to freeze all embryos following OHSS is generally satisfactory, it is important to counsel couples about the possible detrimental effects of OHSS on oocyte quality.

Adult↗
PubMed1996

Risks for transmission of hepatitis C virus during artificial insemination.

OBJECTIVE: To identify risks of hepatitis C virus transmission by semen from infected donors. DESIGN: Case report. SETTING: Assisted fertility clinic. PATIENTS: Hepatitis C virus-infected semen donor and recipients of his donations. INTERVENTION: Testing for hepatitis C virus by serology and polymerase chain reaction. MAIN OUTCOME MEASURES: Detection of hepatitis C virus antibodies and viral RNA. RESULTS: Hepatitis C virus RNA was detected in the semen donation before but not after purification; none of the recipients of the donors samples were found to have antibodies to hepatitis C virus. CONCLUSIONS: Hepatitis C virus RNA can be detected in semen donations from infected donors; purification of donations before insemination significantly reduces the amount of viral RNA in the semen pellet.

Antibodies, Viral↗
PubMed1995

Huntington's disease: diagnosis by amplification of the CAG repeat.

AIM: To develop and validate a test for the diagnosis of Huntington's disease by the direct detection, and sizing of, expanded CAG triplet repeats within the Huntington gene of affected individuals. METHODS: A polymerase chain reaction-based test which specifically amplifies the CAG repeat was developed using an ultra heat stable polymerase and [alpha 35S] delta ATP incorporation. Amplified alleles were separated on DNA sequencing gels and sized by comparison with a known sequence. RESULTS: Analysis of 10 affected individuals showed abnormal alleles with repeat numbers ranging from 40 to 61. In one case, that had been diagnostically uncertain because there was no family history of Huntington's disease, the demonstration of an expanded allele confirmed the diagnosis. Analysis of this patient's elderly and unaffected father indicated that he had an allele at the extreme end of the normal range. In a second case with atypical neurological features the diagnosis was also established by the demonstration of an expanded allele. CONCLUSIONS: This assay allows improved diagnosis of Huntington's disease including completely accurate presymptomatic and antenatal diagnosis. Easy access to this test has implications for clinical practice but acceptable guidelines for its use will need to be developed.

Adult↗
PubMed1995

An evaluation of the effect of pentoxifylline on sperm function and treatment outcome of male-factor infertility: a preliminary study.

OBJECTIVE: Our objective was to study the effect of pentoxifylline (PF) on fertilization rates in couples with previous failure of fertilization and male-factor infertility and to determine the predictive value of conventional semen analysis parameters in selecting the couples who would benefit from the elective use of PF in IVF. DESIGN: This prospective controlled study was conducted in an assisted conception METHODS: Sixty-nine couples with previous failed IVF cycle, who had a low fertilization rate and/or male-factor infertility, were recruited to the study. Multiple follicular development was induced using the same protocol of human menopausal gonadotropin and gonadotropin releasing hormone analogue in both cycles. The oocytes were inseminated with spermatozoa treated with PF. The fertilization rates in the PF cycle were compared to the reference cycle based on semen analysis parameters and previous fertilization rates. RESULTS: In couples with male infertility, the fertilization rate improved significantly, from 17 to 50% in PF cycles (P < 0.001). A significant improvement in fertilization rate was also demonstrated in couples with previous poor fertilization, < 30% (P < 0.01), particularly in those with a very low fertilization rate, < 20% (P < 0.001). Although there was an overall improvement in fertilization rates in couples with male-factor infertility, there was no cutoff value in sperm motility that would make a significant difference in the impact of PF on fertilization rates. CONCLUSION: Couples with poor fertilization rates in vitro benefit with a significant improvement in fertilization by the elective use of PF. The improvement is most significant in couples with previous complete failure of fertilization and poor fertilization rates, < 30%.

Adult↗
PubMed1995

Successful use of pentoxifylline in male-factor infertility and previous failure of in vitro fertilization: a prospective randomized study.

OBJECTIVE: Our objective was to determine whether the use of pentoxifylline (PF) would improve the in vitro fertilization (IVF) rate and outcome in couples with male factor infertility and previous failure of fertilization in vitro. DESIGN: This prospective randomized controlled study was conducted in an assisted conception unit. MATERIALS AND METHODS: Forty-nine couples with previous failed fertilization in vitro attributable to male factor or male-factor infertility without previous IVF were recruited for the study. Controlled ovarian hyperstimulation was performed using a combination of gonadotropin releasing hormone agonist and human menopausal gonadotropin. Oocytes of the same grade and maturity were inseminated with spermatozoa treated with PF or control spermatozoa. A maximum of three embryos was replaced after 48 hr and all other embryos were cryopreserved. Pregnancy outcome was followed up and evidence of fetal or neonatal anomalies reported. RESULTS: A significantly higher fertilization rate occurred in the group where oocytes were inseminated with spermatozoa treated with PF compared with controls (56.3 versus 30.7%; P < 0.05). Fertilization occurred in 45 of the 49 cycles (92%). In seven cycles, only the oocytes that were inseminated with spermatozoa treated with PF fertilized, in contrast to only one cycle where the oocytes inseminated with control sperm fertilized (P < 0.05). Fifty-seven PF and 31 control embryos were replaced and 11 clinical pregnancies occurred. Three of the pregnancies occurred in the seven cycles in which only PF embryos were replaced, one in the single cycle where control embryos were replaced and seven from the 37 cycles in which both PF and control embryos were replaced. There was no evidence of congenital malformations in any of the offsprings resulting from this study. CONCLUSION: This study suggests that PF improves the fertilization rate and outcome in couples with male factor infertility and poor fertilization rates. This study does not suggest any increase in teratogenicity or evidence of congenital malformations in pregnancies following IVF cycles where PF was used.

Adult↗
PubMed1994

The mammalian zona pellucida: its biochemistry, immunochemistry, molecular biology, and developmental expression.

Many studies of the molecular and biochemical aspects of mammalian fertilization have focused on the interaction of the spermatozoa with the zona pellucida (ZP). The zona pellucida, a unique extracellular matrix surrounding the mammalian oocyte, is formed during ovarian follicular development. Following ovulation of the mature ovum, the spermatozoa must bind to and penetrate this matrix before the fertilization process is completed and the male and female genetic information combine. Although numerous models for this interaction have been proposed, the complete process has yet to be elucidated. The precise mechanisms by which these interactions occur also vary markedly among different mammalian species, making it more difficult to establish a unified model. To a great extent, the study of the molecules involved in these interactions have been limited because small numbers of female gametes are available for these studies. The recent development of techniques to isolate large numbers of zonae pellucidae as well as advances in immunological and molecular biology techniques have permitted the detailed characterization of ZP proteins. Although there is a paucity of information on the post-translational modification and extracellular processing of these molecules which result in matrix formation, a number of properties have been elucidated allowing better correlation between the structure and function of different ZP proteins among species. This review reflects these studies in relation to protein nomenclature and the molecular complexity of ZP antigens.

Animals↗
PubMed1990

Rare ectopic pregnancies after in-vitro fertilization: one unilateral twin and four bilateral tubal pregnancies.

Between 1985 and 1989, one unilateral twin and four bilateral tubal pregnancies were encountered among 124 extrauterine pregnancies and 1648 intrauterine pregnancies following in-vitro fertilization and embryo transfer. The two factors associated with this high incidence of single and multiple extrauterine pregnancies were tubal damage and multiple embryo transfer. Embryos at different stages of development appear to have the capacity to implant ectopically. Despite advances in diagnostic capabilities, ectopic pregnancy remains a major cause of maternal mortality. Early diagnosis prior to rupture must be made if mortality and morbidity are to be abolished. The use of transvaginal sonography has improved the diagnosis of ectopic pregnancy and should be routinely used in all pregnancies following assisted conception. The identification of an intrauterine pregnancy should not be sufficient to rule out the possibility of an extrauterine pregnancy or even bilateral tubal pregnancies.

Adult↗
PubMed1990

An evaluation of the hypo-osmotic sperm swelling test as a predictor of fertilizing capacity in vitro.

The ability of sperm to swell in hypo-osmotic conditions was examined in 211 semen samples from the partners of patients about to undergo oocyte retrieval for in-vitro fertilization (IVF). The test was performed using aliquots of semen, the remainder of which was then prepared for IVF. No significant difference was found, in either the percentage of swollen sperm or the type of swelling response, between samples that achieved fertilization in vitro and those that did not, or between any of the diagnostic categories of infertility (tubal damage, unexplained infertility, oligospermia). In samples which achieved fertilization in vitro there were correlations between sperm swelling and sperm motility (r = -0.51) and abnormal morphology (r = 0.33), but no such correlations were demonstrated in samples that failed to achieve fertilization. Moreover, there was no significant difference between the percentage of swollen sperm in semen (mean motility 64%), in samples immediately after preparation for IVF (mean motility 96%) or in capacitated sperm 24 h after preparation (mean motility 91%). These results demonstrate that the hypo-osmotic sperm swelling test does not assist in the prediction of the fertilizing capacity of human sperm in vitro.

Cell Membrane↗
PubMed1986

Follicular aspiration using a syringe suction system may damage the zona pellucida.

The incidence of the formation of cracks in the zona pellucida during aspiration was assessed by comparing two methods of aspirating follicular contents by suction: manual aspiration by syringe and mechanical aspiration by pump. Of 36 patients whose follicles were evacuated manually using syringes, 18 had at least one damaged oocyte. Of 38 other patients whose follicles were aspirated by pump, only one had an oocyte with a cracked zona pellucida. Four patients had their oocytes aspirated by both syringe and pump. In all four, the oocytes were intact when aspirated by the pump, but one oocyte was damaged in three of four cases when the follicles were aspirated using syringes.

Cell Separation↗
PubMed1984

Evolution and resolution of oedema following severe temporary cerebral ischaemia in the gerbil.

Regional cerebral blood flow (rCBF) and oedema following profound temporary ischaemia were studied in the gerbil. Ninety-four per cent of animals died within 24 hours of reperfusion; 50% by 4 hours. Regional differences in oedema (specific gravity method), Evans blue (EB) staining and rCBF (hydrogen clearance technique) occurred. Oedema developed during arterial occlusion, being inversely proportional to residual flow and was markedly exacerbated during reperfusion. Reperfusion hyperaemia was maximal in the parietal and hippocampal regions (ischaemic rCBF 4 ml 100 g-1 min-1). Oedema was disappearing in all areas by 3 hours of reperfusion and autoregulation returned in the occipital region (mean ischaemia rCBF 8 ml 100 g-1 min-1). EB staining and haemorrhage appeared in the thalamus (rCBF 10 ml 100 g-1 min-1) as oedema was decreasing. It is suggested that the amount of oedema and hyperaemia during reperfusion are dependent on the severity of the ischaemia. Areas of moderate ischaemia (8-10 ml 100 g-1 min-1) show little hyperaemia and greater oedema resolution during reperfusion as compared to areas of severe ischaemia (circa 4 ml 100 g-1 min-1) where there is marked hyperaemia with less oedema resolution. Early in the reperfusion period, oedema is not associated with EB staining and indicates a cytotoxic mechanism. The vasogenic component, with macroscopic haemorrhages and leakage of EB occurs later. In this model it is concluded that the early cytotoxic oedema formation and hyperaemia are phenomena with little bearing on mortality, which correlates better with later vasogenic changes.

Animals↗
PubMed1982

Buscopan or glucagon for endoscopic cannulation of ampulla of vater?

The number of intravenous injections of hyoscine-N-butylbromide (Buscopan) or glucagon required to maintain relaxation of the duodenum during endoscopic retrograde cholangiopancreatography (ERCP) were compared in a double blind trial of 55 patients. There was no significant difference in the number of injections. Serum amylase levels after the use of both relaxants were compared in 50 patients undergoing ERCP. No significant difference in the levels of hyperamylasaemia were found.

Ampulla of Vater↗