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Biomedical subjects

R W Shaw

Publications and source records attributed to R W Shaw.

At least 109 records · Page 6Linked to original sources
PubMed1992

Buserelin in premenstrual syndrome.

Buserelin, a luteinizing hormone releasing hormone agonist was administered nasally in doses of 900 micrograms daily to inhibit the ovarian cycle. Of 16 patients recruited, ten completed the treatment. Daily symptoms were measured on the Visual Analogue Scale and Trigg's trend analysis utilized for the analysis. The peak severity of symptoms (ESAmax) and the maximum global scores (Gmax) reduced on buserelin treatment. The minimum global scores (Gmin) and the minimum score for each symptom (ESAmin) increased, suggesting worsening of underlying symptoms. The difference between ESAmax and ESAmin (ESAdelta) and Gmax and Gmin (Gdelta) were calculated to determine the degree of symptom change. The delta scores for symptoms of depression, bloatedness and breast symptoms, and Gdelta were significantly reduced (p less than 0.05) on buserelin, whilst the latter significantly worsened in the follow-up months. Side-effects may limit the place of buserelin in the long-term treatment of premenstrual syndrome, although combination of additional hormonal treatment may facilitate long-term treatment.

Administration, Intranasal↗
PubMed1991

A reexamination of the properties of spinach nitrite reductase: protein and siroheme content heterogeneity in purified preparations.

Recent preparations of nitrite reductase do not display the heterodimeric quaternary structure obtained previously (total molecular weight 85,000; subunit molecular weights 24,000 and 61,000), but rather yield only the 61,000 molecular weight subunit, even when buffers containing the protease inhibitor phenylmethylsulfonyl fluoride are used. Nevertheless, such preparations retain the high ratio of ferredoxin-linked to methyl viologen-linked enzyme activity which has been previously taken as a characteristic of only the heterodimeric form. These preparations display a siroheme prosthetic group to protein ratio of 1.1. When nitrite reductase samples are frozen during the purification scheme, even though the ferredoxin-linked specific activity does not significantly decrease, enzyme activity-stained native gel electrophoresis of the subsequently purified protein reveals that gels with several bands of activity can be obtained. Further evidence of protein heterogeneity in these preparations comes from N-terminal amino acid analysis which reveals that even nonfrozen preparations contain two major peptides with valine and cysteine as the N-termini. Formation of complexes of purified nitrite reductase with ferredoxin resulted in siroheme difference electronic spectra which resembled those observed previously for monomeric preparations. However, the siroheme midpoint potential of recent preparations of nitrite reductase (-287 mV) is close to that of the heterodimeric preparations. Ultrafiltration studies of crude extracts of the enzyme indicate that, at least at certain stages of the preparation, higher molecular weight forms of the enzyme may exist. We conclude that the 24,000 molecular weight polypeptide is a contaminant and that the heterodimeric quaternary structure model for spinach nitrite reductase is incorrect. Furthermore, the monomeric preparations we do obtain display both significant protein heterogeneity and facile loss of siroheme upon gel filtration.

Chromatography, Gel↗
PubMed1991

Progress in optimization of transition metal cation chromatography and its application to analysis of silicon wafer contamination.

Methods are reported which yield sensitive semi-quantitative analysis of transition metal contaminants on silicon wafers. An effective extracting solution is proposed together with compatible concentrators and two eluent (column and post-column) chemistry combinations to measure ppt (10(12)) concentrations and surface densities extending into the 10(10) atoms per cm2 range. Possible applications include numerous steps in wafer and integrated circuit manufacture as well as other solid-surface analysis.

Cations↗
PubMed1991

A within-patient comparison between superovulation with intra-uterine artificial insemination using husband's washed spermatozoa and gamete intrafallopian transfer in unexplained infertility.

The purpose of this study was to evaluate the success of gamete intrafallopian transfer (GIFT) and superovulation with intra-uterine artificial insemination (S-IUI) in couples with long-term unexplained infertility. Thirty-nine couples were offered three attempts at each treatment. Sixty-three IUI cycles were completed with a pregnancy rate of 1.5% per cycle. Forty-nine GIFT procedures were carried out with a pregnancy rate of 26.5% per cycle. The cumulative conception rate after three cycles of GIFT was 0.56. GIFT appears to offer a far greater chance of pregnancy than S-IUI in unexplained infertility.

Adult↗
PubMed1991

Vitrification of mouse oocytes: improved rates of survival, fertilization, and development to blastocysts.

Rall and Fahy's (1985) vitrification procedure for the cryopreservation of 8-cell embryos was applied to unfertilized mouse oocytes. Unchanged, this method resulted in a mean of 24.1% of vitrified oocytes fertilizing and developing to blastocysts in vitro. Exposure of oocytes to the cryoprotectant media, but without the vitrification, resulted in 30.8% developing to blastocysts. Modifications to the durations of and media used in the dilution and equilibration steps of the procedure produced a final protocol giving a mean of 55.4% of vitrified oocytes and 72.4% of nonvitrified VS1-exposed oocytes developing to blastocysts; 85.7% of control oocytes develop to blastocysts. Osmotically induced damage was found to be the most important cause of loss of viability in these methods. Cooling of oocytes to 5-8 degrees C during the procedure had no significant effect on their viability. No parthenogenetic activation of oocytes occurred as a result of exposure to the procedure.

Animals↗
PubMed1991

Assessment of the relevance of zona pellucida antibodies in serum and cervical mucus in patients who have fertilization failure during in vitro fertilization.

OBJECTIVE: To assess whether antibodies to the zona pellucida can cause fertilization failure during in vitro fertilization (IVF). DESIGN: Two methods for detecting zona pellucida antibodies were used to assess 20 women undergoing IVF. Nine patients had failed fertilization during the treatment cycle. SETTING: Academic IVF department of a teaching hospital. PATIENTS: Infertile patients previously assessed as requiring IVF. INTERVENTIONS: Gonadotropin-releasing hormone analogue to achieve pituitary down regulation and human menopausal gonadotropin for superovulation. Transvaginal ultrasound directed oocyte recovery. Cervical mucus and serum samples were obtained. MAIN OUTCOME MEASURES: The presence of antizona pellucida antibodies in serum or cervical mucus in relation to fertilization. RESULTS: Seven of 20 patients had antizona antibodies in serum and 7 of 20 patients had antibodies in mucus. Only 1 patient had antibodies in both samples. No correlation between the presence of antibodies in either sample and failure of fertilization was found. CONCLUSION: Detection of antizona pellucida antibodies by the methods described have no role in the prediction of IVF.

Antibodies↗
PubMed1991

Fertilization and development of the human oocyte following exposure to cryoprotectants, low temperatures and cryopreservation: a comparison of two techniques.

Both glycerol and dimethyl sulphoxide (DMSO) equilibration prior to cryopreservation produced adequate rates of survival and development to the hatching blastocyst stage for mouse oocytes using the two chosen cooling and warming regimes. Successful fertilization of human oocytes and further development of the embryos produced, was achieved following equilibration with DMSO at 0 degrees C. Although fertilization of fresh human ova previously exposed to glycerol was recorded, all oocytes with two pronuclei failed to continue to undergo cell division by 48 h in culture. Following cryopreservation, human oocytes were successfully inseminated after equilibration with both glycerol and DMSO. However, cell division to the 2-cell stage was recorded in only one oocyte which had undergone exposure to DMSO, freezing and thawing. No cell divisions were recorded after glycerol cryopreservation, or even after simple exposure to glycerol. Therefore it appears that DMSO and slow cooling may be the best protocol, although further evaluation will be necessary.

Animals↗
PubMed1991

Evaluation of the risk of pelvic infection following transvaginal oocyte recovery.

The risk of introducing infection into the peritoneal cavity at the time of transvaginal ultrasound-guided recovery of oocytes in assisted reproduction techniques was assessed by culturing peritoneal fluid samples from 25 women with unexplained infertility. The samples were collected laparoscopically at the time of zygote intra-Fallopian transfer (ZIFT), 24-48 h after oocyte collection. High vaginal and endocervical specimens from 25 women treated by in-vitro fertilization (IVF) and transcervical embryo transfer were cultured for comparison. The peritoneal cultures were negative in all but one patient. High vaginal swabs grew Candida albicans in three cases and endocervical specimens were all negative. Seven and three pregnancies occurred in the ZIFT and IVF groups respectively. No pelvic damage was noted at laparoscopy in those women who had had previous treatment cycles with transvaginal oocyte recovery. This method of oocyte recovery, using prophylactic metronidazole and chlorhexidine for preoperative vaginal preparation, appears to be safe for treatment of women with no previous pelvic damage.

Adult↗
PubMed1991

Perceived risk not actual risk predicts uptake of amniocentesis.

A consecutive cohort of 71 women eligible for amniocentesis because they were over 38 years of age completed questionnaires during the first trimester of pregnancy. Sixty-one women underwent amniocentesis, an uptake rate of 86%. Uptake was associated with a less negative attitude towards termination of an affected baby and a higher perceived risk of the fetus being abnormal. It was not associated with actual age-related risks. There was no significant relation between actual risk and perceived risk. The results of this study suggests that it is important for doctors to understand the basis of women's decisions to have amniocentesis, and the difference between actual and perceived risk if they are to communicate effectively with women about the test and their options.

Abortion, Therapeutic↗
PubMed1991

Polycystic ovaries: do these represent a specific endocrinopathy?

Serum pituitary gonadotrophins, oestradiol, testosterone and insulin pulse patterns were examined at 15-min intervals for 6 h in 40 women with a previous diagnosis of polycystic ovarian disease (PCO) based on clinical, endocrinological and ultrasound data. Age, duration of symptoms, body mass index (BMI) and ovarian volume showed no correlation with the 6-h mean value of any hormone and testosterone blood levels did not correlate with those of insulin. Some patients had high and others low LH pulse pattern components, and few had an inverted LH:FSH ratio. Morphological polycystic ovarian changes may be a reflection of various rather than a single pattern of gonadotrophin secretion.

Adult↗
PubMed1991

Phospholipase activity in the endometrium of women with normal menstrual blood loss and women with proven ovulatory menorrhagia.

The activity of phospholipase A2 types 1 and 2 and phospholipase C was measured in the endometrium of women with ovulatory menorrhagia and in those with normal menstrual blood loss. In both groups of subjects phospholipase A2 type 1 activity was significantly higher in the secretory phase than in the proliferative phase (P less than 0.001). The median activity (pmol/mg protein/min) for the proliferative phase was 27.6 in normal subjects and 40.4 in women with ovulatory menorrhagia and for the secretory phase the median activity was 144.5 in normal women and 138.1 in women with ovulatory menorrhagia. There was no difference between the two groups of women at either stage of the cycle. Phospholipase A2 type 2 activity was also higher in the secretory phase than in the proliferative phase (P less than 0.05 for normal subjects and P less than 0.001 for women with menorrhagia). The median activity (pmol/mg protein/min) for the proliferative phase was 94.4 (normal subjects) and 56.6 (women with menorrhagia) and for the secretory phase 148.3 (normal subjects) and 142.5 (women with menorrhagia). The activity of phospholipase A2 type 2 was significantly lower in the proliferative phase of women with ovulatory menorrhagia compared with normal subjects (P less than 0.05). Phospholipase C activity (nmol/mg protein/min) was significantly higher in women with ovulatory menorrhagia (median 8.2) compared with women with normal blood loss (median 5.5) (P less than 0.01).

Endometrium↗
PubMed1991

Endometriosis: the next ten years.

Several modalities can be employed in managing the patient with endometriosis, but the ultimate selection is determined by evaluating a number of criteria including age, extent of disease, severity of symptoms and pain. Scoring systems used in many clinical trials are based on the Revised American Fertility Society system but have their limitations. There is a possibility of using such innovations as receptor studies to individualize therapies in the future. Future research must also include dose-response studies, not only for the new GnRH agonists but also for danazol. These are essential to investigate efficacy. It may be that the different subtypes of endometriosis require quite dissimilar approaches to achieve the therapeutic goal. Despite advances in therapy for endometriosis, the disease remains largely a mystery in terms of its aetiology and pathogenesis, but we are drawing closer to refining our diagnostic and scoring techniques and individualizing our approach to therapy.

Endometriosis↗