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Biomedical subjects

D M Saunders

Publications and source records attributed to D M Saunders.

At least 37 records · Page 2Linked to original sources
PubMed1995

Isolation of ERp72 from guinea pig term placentae using heparin Sepharose affinity chromatography.

The mammalian placenta synthesises many varied antigens, including proteins, such as hormones, enzymes and protease inhibitors. In this report, we isolated and purified the two protein isomerase-related protein precursor ERp72 isoforms from aqueous extracts of guinea pig placenta, by four (4) chromatographic procedures; i) affinity chromatography on immobilised heparin, ii) gel filtration (Ultrogel AcA-54), iii) anion exchange chromatography (Mono-Q), and, iv) negative immunoaffinity chromatography. From 20 term placentae, the final yield of ERp72 isoforms was 2.4mg (Mr 71.5 kDa) and 1.5mg (Mr 75.8 kDa). Identity was confirmed by NH2-terminal amino acid sequencing which demonstrated 85% homology to human ERp72. By indirect immunofluorecence. ER p72 expression was demonstrated in tunicamycin stressed pre-implantation embryos and unfertilised oocytes. These findings demonstrate the potential for immunological monitoring of ERp72 expression, by cultured oocytes and embryos, during manipulation by assisted reproductive technologies.

Amino Acid Sequence↗
PubMed1994

Short-term corticosteroid treatment does not improve implantation for embryos derived from subzonal insertion of sperm.

A total of 111 patients undergoing treatment for male factor infertility using SUZI participated in the trial for one treatment cycle only. They were allocated to have either corticosteroid treatment to induce immunosuppression or placebo. An elevated beta-hCG was found in 25% (9 of 36) of patients having an ET and receiving treatment. The corresponding figure for the control group was 33% (10 of 30). On ultrasound examination, fetal hearts were found in 22% (8 of 36) and 20% (6 of 30), respectively, of patients having an ET. chi 2 analysis showed no difference in the results. When the results were analyzed on a per oocyte basis there was no significant difference in the implantation rate.

Embryo Implantation↗
PubMed1994

Removal of the zona pellucida and parthenogenetic activation affect rates of survival of ultrarapidly frozen mouse oocytes.

Survival rates on thawing were assessed for ultrarapidly frozen mouse oocytes following the removal of zonae pellucidae using an acid Tyrode's solution, pronase or a mechanical dissection technique. Significantly higher rates of survival were observed for zona-free oocytes than for zona-intact control oocytes (303/684, 44% v. 130/498, 26%; P < 0.001). The rates of survival observed for pronuclear stage embryos (72-76%) were much greater than those observed for oocytes and were not influenced by zona removal techniques. Parthenogenetic activation of oocytes by exposure to a 7% (v/v) ethanol solution was also shown to increase survival rates of ultrarapidly frozen oocytes (155/185, 84% v. 19/102, 19%) indicating that fusion of sperm to the plasma membrane or formation of a male pronucleus are not directly responsible for the increased survival rates of pronuclear stage embryos compared with oocytes. These data support the hypothesis that increased survival of ultrarapidly frozen pronuclear stage embryos is the result of changes to the plasma membrane and/or to the zona pellucida that occur following fertilization.

Animals↗
PubMed1994

Community attitudes to maternal age and pregnancy after assisted reproductive technology: too old at 50 years?

Community attitudes toward oocyte and embryo donation, and toward assisted reproduction after the menopause were assessed in this survey of 1131 Australians. Of the respondents, 64.2% believed that oocyte or embryo donation was an acceptable treatment for infertile couples, 54.6% felt that it was acceptable for a woman to have her own embryos transferred after the menopause, and 37.9% are accepting of the donation of eggs or embryos to post-menopausal women. There were no significant differences in response amongst different religious groups, or in relation to gender or income level. Significantly higher levels of acceptance were noted for all categories amongst those respondents aged < 35 years. Despite the established clinical ability to achieve pregnancy in the over 50 years age group, this survey reveals only minority community support for this practice. However, public opinion may alter in the future if the attitudes of the younger proportion of the sample are maintained.

Adolescent↗
PubMed1993

Clinical outcomes of pregnancies achieved by microinsemination by sperm transfer.

Micromanipulative techniques such as microinsemination by sperm transfer are evolving as treatment for couples suffering from some forms of male factor infertility where previously donor insemination was the only option. Being a relatively new technology, the numbers of microinsemination by sperm transfer pregnancies that have progressed to term are still small. However, at this time, it would seem that outcome in terms of antenatal complications, gestation length, and birth weight is no different from that seen with conventional IVF. Continuing review of the rate of congenital malformation in microinsemination by sperm transfer progeny seems warranted.

Abortion, Induced↗
PubMed1993

A comparison of early pregnancy failure and ongoing pregnancy rates between fresh and frozen embryo transfer following in vitro fertilization.

In order to compare pregnancy outcomes following fresh and frozen embryo transfer after in vitro fertilization (IVF), a retrospective analysis of data from the Royal North Shore IVF Programme was performed. Six hundred and sixty seven embryo transfers following routine IVF were performed during 1991 and 1992. Four hundred and twenty fresh embryo transfers were performed during that period, resulting in a clinical pregnancy rate of 21%. In comparison, 247 frozen transfers, where the initial procedure was routine IVF, were performed, resulting in a clinical pregnancy rate of 16.6%. This difference was not significant. When varying numbers of transferred embryos in the 2 groups were taken into account, there was a significant difference in the proportion of ongoing viable fetuses per embryo returned for 1991, but not for 1992. Although there were a greater number of abortions and ectopic pregnancies in the fresh transfer group, these differences did not achieve statistical significance. The implications of improving results from frozen embryo transfer are discussed.

Abortion, Spontaneous↗
PubMed1993

Significance of assisted reproductive technology for other areas of medicine.

Assisted reproductive technology has achieved its place in the management of women with infertility. It is now being used to refocus gynaecological attention on patients with other enigmatic benign gynaecological conditions, such as endometriosis, and their medical treatments. Now that reasonable success rates can be achieved without risking unacceptable multiple pregnancy rates, many other medical disciplines are becoming involved. Specialists in these other disciplines need to modify their treatments accordingly to allow for future parenthood if this is appropriate. These specialists need also to be aware of past ethical dilemmas that infertility units have had to confront during the first ten years of this new technology.

Endocrinology↗
PubMed1992

In-vitro fertilisation and neonatal ventilator use in a tertiary perinatal centre.

OBJECTIVE: To determine the contribution of livebirths resulting from in-vitro fertilisation and related technologies (IVF) to the use of neonatal ventilator beds. DESIGN: A retrospective review of records of all livebirths from our hospital's IVF program and all IVF infants receiving mechanical ventilation in our neonatal intensive care unit for the period 1985-1989. We also reviewed records of labour ward deliveries, neonatal intensive care unit admissions and transfer requests in order to obtain comparative data for livebirths of non-IVF infants whose mothers had been booked to deliver in our hospital. SETTING: A tertiary perinatal centre with a large IVF program and a Level 3 neonatal intensive care unit. RESULTS: IVF livebirths accounted for 5.1% of total ventilator bed days. Compared with non-IVF booked livebirths, IVF babies were more likely to require ventilation (odds ratio, 7.41; P less than 0.0001) and used more ventilator bed days per 100 livebirths (rate ratio, 9.63; P less than 0.0001), largely due to preterm delivery of multiple pregnancies; 42.3% of IVF babies who required ventilation were from triplet births and 38.5% from twin births. Nevertheless, even IVF singletons used more ventilator bed days per 100 livebirths than non-IVF booked livebirths (rate ratio, 2.78; P less than 0.0001). IVF livebirths accounted for 9.9% of the 78% increase in ventilator bed days used in 1989 compared with 1985. CONCLUSIONS: IVF livebirths accounted for only a small percentage of the overall use of neonatal ventilator beds, but consumed relatively more of such resources per livebirth than did non-IVF livebirths. The degree of risk of requiring ventilation is directly related to the number of infants in a multiple pregnancy, but even IVF singletons are at a relatively high risk of requiring ventilation.

Female↗
PubMed1992

Increased pregnancy failure rates after clomiphene following assisted reproductive technology.

The obstetric outcome of 1941 in-vitro fertilization (IVF) and 1436 gamete intra-Fallopian transfer (GIFT) pregnancies reported from 25 units in Australia and New Zealand have been reviewed. Recently, gonadotrophin-releasing hormone analogues (GnRHa) have replaced clomiphene as part of many ovarian stimulation protocols. Clinical abortion rates after clomiphene (24.4% for IVF; 23.0% for GIFT) were not significantly higher than after GnRHa (20.7% for IVF; 17.9% for GIFT) when IVF and GIFT data were considered separately. However, the abortion rate for combined IVF and GIFT was significantly higher after clomiphene than after GnRHa. This pattern was found for most maternal age groups and causes of infertility although differences were not significant in all categories. The combined IVF and GIFT ectopic pregnancy rate of 6.7% for clomiphene was significantly higher than 4.1% for GnRHa. Because the mechanism of action of clomiphene for oocyte recruitment during folliculogenesis means that GnRHa cannot be used with clomiphene, luteinizing hormone (LH) levels are higher in clomiphene cycles than in GnRHa cycles. Clomiphene itself could cause the increase in pregnancy wastage or increased levels of LH during follicule genesis associated with the use of clomiphene may cause the observed pregnancy failures.

Abortion, Spontaneous↗
PubMed1992

The influence of maternal age on cesarean section rates.

Caesarean section rates have risen in recent years and this has led to concern. Significantly different Caesarean section rates have been reported between different teaching hospitals. This study compares the Caesarean section rates between 2 Sydney teaching hospitals draining populations from different areas of Sydney. Raw figures showed significantly different Caesarean section rates (22.5% at Royal North Shore Hospital compared with 18.3% at Westmead Hospital). Each hospital has a significantly different case mix when maternal ages are compared. When Caesarean section rates were corrected for maternal age and parity, there was no significant difference. As maternal age is an important factor influencing Caesarean section rates, future reports on obstetric services should consider this factor in making comparisons.

Adult↗
PubMed1991

Detection of anti-ovarian antibodies by indirect immunofluorescence in patients with premature ovarian failure.

The sera of 30 patients with premature ovarian failure (POF) and a control group of 19 menopausal women were screened for anti-ovarian and other tissue antibodies. Anti-ovarian antibodies were detected by indirect immunofluorescence using monkey ovary substrates from two different commercial sources. Serum anti-ovarian antibodies were detected in only one of the patients with POF. This test does not appear to be reliable for the detection of serum anti-ovarian antibodies, and the clinical usefulness of screening patients with POF for anti-ovarian antibodies is questionable.

Adrenal Glands↗