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Biomedical subjects

D M Saunders

Publications and source records attributed to D M Saunders.

At least 19 recordsLinked to original sources
PubMed1995

Clinical intracytoplasmic sperm injection (ICSI) results from Royal North Shore Hospital.

The technique of intracytoplasmic sperm injection (ICSI) was first introduced to the Royal North Shore Hospital in April 1993 as part of a controlled study of 100 patient cycles in which sibling oocytes were inseminated by either subzonal insemination (SUZI) or ICSI. This trial showed direct sperm injection to be superior in terms of fertilization. In that study, 58 embryo transfers of 101 ICSI-derived embryos resulted in 10 pregnancies. No miscarriages have occurred and a total of 10 fetal hearts (9.8% per embryo transferred) were detected on ultrasound. There have been 10 deliveries of 10 babies. Since the beginning of 1994, intracytoplasmic injection has been used exclusively for patients requiring micromanipulation to achieve fertilization. There have been 200 patient cycles with 1650 oocytes collected (8.8 oocytes per cycle). Of these oocytes, 1548 were mature (94%) and were subjected to ICSI, and normal fertilization occurred in 874 (56%) of the injected oocytes. The number of oocytes which cleaved and were suitable for fresh transfer or cryopreservation was 818 (94%). There have been 153 fresh embryo transfers of 326 embryos. Twenty-six pregnancies (17% per embryo transfer) have resulted, 22 of which proceeded to ultrasound examination in which 23 fetal hearts were detected (7% per embryo transferred). Three miscarriages have occurred, leaving 19 ongoing pregnancies. There have been 127 cryopreservation procedures involving 492 embryos. To date, there have been 47 embryo thaw cycles, and 93 of the 115 (81%) thawed embryos survived and were transferred. These 47 embryo transfers resulted in 10 pregnancies (21% per embryo transfer), one of which one has miscarried.(ABSTRACT TRUNCATED AT 250 WORDS)

Australia↗
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↗
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↗
PubMed1991

Radioimmunoassay of inhibin based on synthetic human inhibin alpha-chain peptide.

Polyclonal rabbit antisera were produced against cyclic human inhibin [(Cys6, Tyr7) alpha-(6-30)NH2] peptide, covalently conjugated to bovine serum albumin. The tyrosine residue introduced at position 7 facilitated the oxidative incorporation of radiolabel (125I) to yield a tracer with specific activity of 73.9 Ci/g. These reagents were used to develop a homologous equilibrium radioimmunoassay for human inhibin, with polyethylene glycol, 200 g/L, serving as the separation phase. At a detection limit of 2 micrograms/L (n = 7), immunoactive inhibin was detectable in human pre-ovulatory follicular fluid (128 micrograms/L), seminal plasma (2374 micrograms/L), amniotic fluid (66 micrograms/L), and placental extract (347 micrograms/L). We also demonstrated inhibin immunoreactivity in biological fluids from other mammalian species: macaque, chimpanzee, porcine, and bovine, but not rodent (guinea pig). Although the antisera were raised against a nonbioactive inhibin peptide, immunoglobulins fractionated on Protein A-Sepharose neutralized the bioactivity of human ovarian inhibin. Further characterization of inhibin immuno- and bioactivity was undertaken with immobilized heparin, divalent metal cations, and dye ligands. Only heparin-Sepharose distinguished between immuno- and bioactive inhibin.

Amniotic Fluid↗
PubMed1990

A baboon model for pregnancy-associated antigens (PAPP-A, PP5, PP14).

By radioimmunoassays established on human derived antigens, PAPP-A, PP5 and PP14 immunoreactivity was detected in placental extracts and blood of pregnant baboons. None of the serial dilution curves suggested parallelism between respective human and baboon samples. Based on slopes of regressed logit-log transformed binding data, PAPP-A demonstrated the greatest degree of interspecies immunological crossreactivity. PP14 showed the least conservation of antigenic determinants. Physicochemical characterization on heparin, zinc chelate and bovine thrombin affinity matrices could not distinguish human from baboon-derived antigens. As in the human, baboon PAPP-A and PP5 were not detected in blood of male or non-pregnant animals. PP14 was detected in baboon follicular fluid, and only PP5 immunoreactivity was measured in culture media of baboon embryos. Of the three antigens, PAPP-A was detected in pregnant baboons at about 61 days gestation, that is, 4 weeks before PP5 and PP14. With the exception of PP14 which attained peak concentration at 118 days of pregnancy, PAPP-A and PP5 concentrations were greatest at term. In conjunction with physicochemical and immunological criteria, these physiological kinetics clearly support a role for developing a baboon model to serve for further studies into feto-maternal signals, particularly antigens such as PAPP-A and PP5.

Animals↗
PubMed1990

Elevated luteal phase estradiol:progesterone ratio in mice causes implantation failure by creating a uterine environment that suppresses embryonic metabolism.

Failure of implantation after in vitro fertilization is sometimes associated with elevated estradiol (E2):progesterone (P) ratios in the early luteal phase. Using the mouse to study the causes of the contragestational actions of elevated E2:P ratios, it was confirmed that administration of E2 (40 to 80 ng) before implantation inhibited implantation and 0.4 mg of P totally reversed the effect of 40 ng E2. Fluids collected from the uterine lumen of E2-treated (40 ng) mice significantly inhibited the incorporation of 3H-uridine by mouse blastocysts in vitro, whereas fluids from mice treated with E2 (40 ng) and P (0.4 mg) together had no inhibitory effect. In contrast to these contraceptive effects of high E2, lower levels of E2 (5 and 20 ng) caused an increase and no change to the implantation rate, respectively, and fluids from mice treated with E2 (20 ng) significantly enhanced blastocyst metabolism. Concomitant administration of P to these low dose E2 mice enhanced these effects. Thus, a large elevation of the E2:P ratio inhibited implantation and created a uterine lumenal milieu that suppressed embryonic metabolism. These effects could be reversed and implantation re-established by the correction of the E2:P ratio by exogenous P.

Animals↗
PubMed1990

Measurement of human embryo-derived platelet-activating factor (PAF) using a quantitative bioassay of platelet aggregation.

A quantitative bioassay was used to measure the concentration of platelet activating factor (PAF) in medium in which human embryos produced by IVF had been cultured and in various other biological fluids. Following extraction and partial purification, 121 of 228 (53%) media samples in which single human embryos were cultured for 24 h had PAF levels greater than found in corresponding control media. This was assigned as embryo-derived PAF and the corresponding embryos termed 'PAF-positive'. Medium from those PAF-positive embryos transferred to patients who achieved an ongoing pregnancy had a mean PAF concentration of 295 +/- 107 nM (mean +/- SEM, n = 55), which was significantly greater (P less than 0.03) than media of PAF-positive embryos transferred to patients who failed to become pregnant (75 +/- 27 nM, n = 66, t-test). The embryos with the faster cleavage rates tended to secrete more PAF (P less than 0.01). Although a greater proportion of culture media derived from embryos transferred to patients who achieved a pregnancy were PAF-positive (66 out of 121, 54.5%) compared with those transferred to patients who failed to achieve a pregnancy (55 out of 121, 45.4%), this was not significant (P greater than 0.05). It was observed that 13% of women who achieved a pregnancy had embryos transferred which did not produce significant amounts of PAF in vitro. This occurred in 26% of women not achieving pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Assay↗
PubMed1990

A protein marker of hamster oocyte fertilization.

Using a polyclonal rabbit antiserum directed against guinea-pig heparin-binding placental protein (HBPP), we have demonstrated by indirect immunofluorescence the expression of this antigen by hamster preimplantation embryos. HBPP was localized to blastomeres, but not to the zona pellucida, of hamster preimplantation embryos conceived in vivo. Hamster embryos, from the pronuclear to hatched blastocyst stages, were HBPP-positive with greatest immunofluorescence detected at the pronuclear to 2-cell stages. Thereafter, HBPP-dependent fluorescence diminished. By contrast, mature spermatozoa and unfertilized metaphase II oocytes were HBPP negative. Direct microinjection of spermatozoa or diluent through the zona pellucida and into the ooplasm activated the oocytes to express HBPP. These findings demonstrate that expression of HBPP is a post-conceptional event limited to fertilized (or activated) oocytes and that transcription of paternal genomes was not required for HBPP expression. The distribution and temporal kinetics suggest that HBPP may be secreted or released by activated cortical granules into the perivitelline space and concentrated at the oolemma. Whereas hamster embryos conceived in vivo consistently demonstrated a uniformly distributed immunofluorescence, non-viable and degenerate embryos showed weak and patchy reactions. Thus, we have identified a heparin-interacting protein which may serve as a marker of in-vivo and in-vitro oocyte activation and embryo quality.

Animals↗