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Biomedical subjects

R W Shaw

Publications and source records attributed to R W Shaw.

At least 55 records · Page 3Linked to original sources
PubMed1997

A new species of Loma (Microsporea) in shiner perch (Cymatogaster aggregata).

Loma embiotocia n. sp. is described from the gills of shiner perch (Cymatogaster aggregata) from waters off Vancouver Island, British Columbia, Canada. Highest prevalence at a site was 15% and greatest intensity was 583 xenomas per fish. Xenomas averaged 0.13 mm in diameter (0.06-0.16 mm) and contained ovoid spores 4.8 x 2.6 (4.0-5.0 x 2.0-3.0) microns. Sporogonic stages were dispersed throughout the xenomas. The xenoma wall was smooth lacking invaginations into the cyto plasm: sporoblasts were not highly vacuolated, and the sporophorous vesicle formed before sporogony. In addition to differences in host and geographic location the new species is distinguished from Loma salmonae, the only other species in the genus known from British Columbia, by its internal transcribed spacer (ITS) ribosomal DNA sequence.

Animals↗
PubMed1997

Infection of Aulorhynchus flavidus (Gill) (Osteichthyes: Gasterosteiformes) by Kudoa thyrsites (Gilchrist) (Myxosporea: Multivalvulida).

The myxosporean parasite Kudoa thyrsites is reported from a new host, Aulorhynchus flavidus, the tube-snout, collected near Vancouver, British Columbia, Canada. Prevalence reached 100% and intensity 1,535 pseudocysts per 2 cm length of fish. Polymerase chain reaction primers specific for K. thyrsites amplified a fragment of the small subunit rDNA and confirmed identification. These primers also allowed detection of K. thyrsites in young (< 4-mo-old) fish with no other apparent sign of infection. No inflammatory response or liquefaction of host tissue was associated with the infection. The number of pseudocysts per infected fish was not correlated with fish size or condition, although larger fish (total length) had larger pseudocysts (rs = 0.437, P < 0.001). This finding brings to 28 the number of potential hosts for the species. Kudoa thyrsites is a well recognized cause of soft flesh in netpen-reared Atlantic salmon in coastal waters of British Columbia. Tube-snouts are common in and around these netpens, and thus may be a significant host reservoir for K. thyrsites.

Animals↗
PubMed1996

The effect of add-back treatment with tibolone (Livial) on patients treated with the gonadotropin-releasing hormone agonist triptorelin (Decapeptyl).

OBJECTIVE: To assess whether tibolone can prevent the bone loss and symptomatic side effects normally associated with GnRH agonist (GnRH-a) use and whether tibolone modifies the effect of GnRH-a on endometriosis. DESIGN: Prospective, double-blind, placebo-controlled, group comparative study. SETTING: Gynecological research unit in a London teaching hospital. PATIENTS: Twenty-nine patients with endometriosis and two with fibroids. INTERVENTIONS: Six months of treatment with 3.75 mg/mo IM triptorelin combined with daily tablets of either placebo or 2.5 mg tibolone. MAIN OUTCOME MEASURES: Daily symptom diary for hot flushes and bleeding episodes, laparoscopic scoring of endometriosis, endocrine and biochemical changes, and bone mineral density scans. RESULTS: Lumbar spine bone mineral density decreased significantly from baseline in the placebo group (-5.1%) but not in the tibolone group (-1.1%). The frequency of hot flushes and sweating episodes was reduced significantly by tibolone. There was no difference between the two treatment groups with regard to the endometriosis scores. CONCLUSIONS: The addition of tibolone to GnRH-a treatment reduces the bone loss and vasomotor symptoms that normally occur with GnRH-a, thus making long-term treatment with GnRH-a safer and more acceptable. It does not negate the therapeutic effect of GnRH-a on endometriosis.

Adult↗
PubMed1996

Effect of maternal age on clinical outcome in women undergoing in vitro fertilization and embryo transfer (IVF-ET).

The purpose of this study was to assess the effect of age of IVF success in women undergoing in vitro fertilization and embryo transfer by comparing IVF outcome in two groups of patients: group 1-age < or = 35 years old and group 2-age > 35 years old. This retrospective study covered a one year period between January 1991-December 1991 and included 230 patients with 634 treatment cycles. The patients' mean age was 32 +/- 1.9 (range 20-38 years old). Inclusion criteria for treatment of patients with IVF-ET included patients with tubal disease and non-tubal disease who have failed conventional treatments. The majority of patients had infertility from tubal damage, unexplained infertility, and male infertility. This study showed that all pregnancy rates, ongoing pregnancy rates and implantation rates were found to be higher in the < or = 35 year old group. The pregnancy rate per ET, ongoing pregnancy rate and implantation rate were found to be 35.17, 27.58, 16.53 per cent respectively; while in the > 35 year old group, the pregnancy rate per ET, ongoing pregnancy rate, implantation rate were found to be only 17.93, 11.03, 8.07 per cent respectively. The miscarriage rate tended to be higher in the > 35 year old group (34.62%) compared to 15.69 per cent found in < or = 35 year old group. Multiple pregnancy rate and ectopic pregnancy rate were found to be 17.65 and 5.89 per cent respectively for the < or = 35 year old group but only 7.69, 3.85 per cent respectively for the > 35 year old group. From the statistical analysis comparing the outcome of pregnancy in these two groups, the pregnancy rate per ET, implantation rate, ongoing pregnancy rate and miscarriage rate were found to have statistical difference with P < 0.05. However, multiple pregnancy rate and ectopic pregnancy rate did not show any statistical significance in these two groups (P > 0.05). In conclusion, the results of this study indicated that maternal age especially when greater than 35 years old adversely affects clinical pregnancy and the spontaneous abortion rate.

Adult↗
PubMed1996

The influence of number of embryos transferred on pregnancy outcome in women undergoing in vitro fertilization and embryo transfer (IVF-ET).

The purpose of this study was to retrospectively examine the influence of number of embryos transferred on pregnancy outcome in women undergoing in vitro fertilization and embryo transfer (IVF-ET) between July 1990-December 1991 at the Royal Free Hospital, London, United Kingdom. This study included three groups of patients: group 1-the number of embryo used for transferring was one embryo, group 2-the number of embryos used for transferring was two embryos and group 3-the number of embryos used for transferring was three embryos. This study demonstrated that the clinical pregnancy rate increased significantly when transferring two or three embryos compared to one. But this rate did not differ significantly when two embryos were compared with three embryos. The multiple pregnancy rate, miscarriage rate, and ectopic pregnancy rate did not differ significantly among the three groups studied but there was a risk of higher order multiple pregnancy if more embryos were transferred. In this study we found 3 triplets out of 35 pregnancies when 3 embryos were transferred (Group 3). In conclusion, this study demonstrates that when two or three embryos were transferred the clinical pregnancy rate increased significantly. Transferring two embryos instead of three did not alter the pregnancy rate. Moreover, triplets pregnancies were eliminated. Therefore, we suggest limiting the number of embryos to be transferred at two and the supernumerary embryos should be cryopreserved for future transfer.

Adult↗
PubMed1995

Training obstetricians and midwives to present screening tests: evaluation of two brief interventions.

The objective of this study was to assess the effects of two brief training interventions to improve obstetricians' and midwives' explanations to patients of a routine prenatal screening test. Health professionals were randomly allocated to one of two intervention groups or a control group. Information-giving about the test and communication skills were assessed at baseline, post-training and 3-month follow-up from audiotaped consultations. Both intervention groups received a 1-h training session involving small group discussions focused around a video. In addition, one group received individual feedback on their baseline and post-training consultations. Twenty-six midwives and nine obstetricians completed the study according to the protocol. Changes between baseline and post-training, and between baseline and follow-up, were computed. Information-giving and communication skills improved significantly in subjects receiving training and feedback on their performance, with the greatest improvements occurring before feedback was given. Those receiving training without feedback significantly improved their communication skills and showed some improvement in information-giving. These results show that modest improvements in communication can be made with relatively brief training. Greater and more sustained improvements may be found if all staff were trained, and trained on a regular basis.

Communication↗
PubMed1995

The effect of cooling and hypertonic exposure on murine oocyte function, fertilization, and development.

Several individual but related steps are involved in the cryopreservation process, including the addition of cryoprotectants at various temperatures, cooling to subzero temperatures, and long-term storage. The process is completed by rewarming and removal of cryoprotectants prior to a return to physiological conditions. In this series of experiments we have attempted to distinguish the effects of some of these procedures. Control, untreated ovulated mouse oocytes showed 95% in vitro fertilization (190/200) and 92% subsequent development to hatching blastocyst (184/200). Exposure of oocytes to either isotonic or hypertonic media at 37 degrees C did not significantly change the rate of fertilization (90%, 108/120; and 89%, 154/174, respectively) or subsequent embryonic development (85%, 102/120; and 82%, 143/174, respectively). Slow cooling in isotonic medium (-3 degrees C/min) to 0 degree C had no effect on the rate of fertilization (83%, 103/124), but rapid cooling (> 1000 degrees C/min) to 0 degree C resulted in a significant reduction in fertilization rate to 75% (151/202). When oocytes suspended in a hypertonic solution were cooled using slow or rapid rates, there were marked decreases in fertilization to 26% (61/231) and 56% (156/278), respectively. Subsequent embryonic growth was reduced to 15% (34/231) after slow cooling and 26% (72/278) after rapid cooling. Exposure of oocytes to glycerol at 37 degrees C and dimethyl sulfoxide at 0 degree C reduced the fertilization rate to 57% (67/118) and 73% (103/145), respectively, with a corresponding reduction in embryonic growth to 52% (61/118) and 65% (94/145), but there were no additional effects of cooling or hypertonic exposure after addition of cryoprotectants.

Animals↗
PubMed1995

The effects of gonadotrophin-releasing hormone agonists on iliac crest cancellous bone structure in women with endometriosis.

The administration of gonadotrophin-releasing hormone (GnRH) analogs to premenopausal women causes hypoestrogenism and bone loss, but the effects on cancellous microstructure have not been determined. In this study we have assessed bone structure in transiliac biopsies obtained from women before and after treatment for endometriosis with GnRH analogs. Twenty-one premenopausal women were studied, paired biopsies being obtained in 13; five women received both GnRH analogs and Org OD 14 (Tibolone, Livial). Comparison of pre- and post-treatment biopsies in women treated only with GnRH analogs showed a reduction in indices related to connectivity (node-to-terminus ratio, node-to-loop strut length, p < 0.02) and increase in inversely related indices (terminus-to-terminus and node-to-terminus strut length, p < 0.03). No significant changes were seen in any of the structural indices in women receiving both GnRH and Org OD 14 therapy. Activation frequency and bone formation rate at tissue level increased in women treated with GnRH agonists alone, although this change was not statistically significant. Our results suggest that bone loss induced by GnRH analogs may be associated with adverse effects on cancellous microstructure which are unlikely to be reversed following cessation of therapy. Concurrent treatment with Org OD 14 appears to prevent these changes.

Adult↗
PubMed1995

Endometriosis, pelvic pain, and psychological functioning.

OBJECTIVE: To investigate whether there are psychological differences between women with symptomatic as opposed to asymptomatic mild endometriosis. DESIGN: Forty-nine women with minimal or mild endometriosis completed the Beck Depression Inventory, the Speilberger State-Trait analysis, and the Golombok Rust Inventory of Sexual Satisfaction. Women admitted for sterilization acted as normal controls and women complaining of pelvic pain with no organic pathology were studied also. SETTING: Tertiary referral centers for endometriosis. MAIN OUTCOME MEASURES: Women with pelvic pain symptoms, whether they had mild endometriosis or a normal pelvis, had similar scores for the Beck Depression Inventory. These scores were significantly higher than those of women with asymptomatic disease and normal women admitted for sterilization. CONCLUSIONS: Women with mild endometriosis should not be included as a control group when studies on pelvic pain are planned.

Adult↗
PubMed1995

The ultrasound diagnosis and clinical significance of varicocele.

A study was carried out to determine the relationship between clinically diagnosed and ultrasound-diagnosed varicoceles in 151 men with normal and abnormal semen analysis. In only 60 cases (40%) was the clinical diagnosis confirmed by ultrasound. Of the men with ultrasound-diagnosed varicocele, 14% were found to have a normal semen analysis compared to 31% of men without a varicocele, and this difference was statistically significant (p < 0.05). Bilateral varicoceles were associated with an even greater chance of having an abnormal semen analysis (p < 0.01), and with a significantly (p 0.05) decreased chance of spontaneous pregnancy. These men and also men with unilateral varicocele, whose partners have a relative cause of female subfertility, may benefit from earlier intervention for the treatment of their subfertility.

Adult↗
PubMed1995

Vitrification of human oocytes following minimal exposure to cryoprotectants; initial studies on fertilization and embryonic development.

Investigations were made into the low temperature preservation of pre-ovulatory human oocytes by vitrification using a method of brief exposure of the oocytes to the vitrification solution at room temperature. Assessments of morphological survival, fertilization and embryonic development were recorded. All those oocytes exposed to the vitrification solution alone were morphologically normal and 86% of them were fertilized after incubation with spermatozoa. All the fertilized ova (86%) underwent cell division. Following cooling to -196 degrees C, morphological survival (65%) and fertilization (45%) rates remained high. However, in all vitrified oocytes, embryonic cell division and further development were inhibited. From our study it appears that fresh human oocytes can be vitrified using only brief exposure to cryoprotective agents and survive to undergo fertilization. However, progress remains to be made in achieving further embryonic development.

Cell Survival↗
PubMed1995

Postcaesarean section uterovesical fistula lined by persistent intermediate trophoblast.

We report a unique case of a postcaesarean section uterovesical fistula lined by intermediate trophoblast. The patient, a 42-year-old woman, presented with cyclical haematuria, and she had had a lower segment caesarean section 1 year previously. She was found to have uterovesical fistula, which was excised. On microscopic examination the fistula tract was lined by intermediate trophoblast characterised by cells with abundant eosinophilic cytoplasm, occasional multiclefted nuclei, and cytoplasmic immunoreactivity for epithelial cytokeratins and human placental lactogen. This finding has not, to our knowledge, been previously described and indicates that the survival of third trimester intermediate trophoblast is independent of pregnancy.

Adult↗
PubMed1995

Morphological changes in uterine leiomyomas treated by GnRH agonist goserelin.

To elucidate the mechanisms of action of GnRH agonists on uterine leiomyomas, morphometric and ultrastructural studies have been carried out on leiomyomas from patients treated with goserelin, and comparisons made with untreated tumors. The treated cases showed a variable degree of reduction of uterine size associated with leiomyoma shrinkage, and there was a correlation between the volume loss and the original size of the uterus. The morphological features of the treated lesions were very variable, with some showing evidence of marked cellular shrinkage and ultrastructural cytoplasmic changes, some having a lymphoid cell infiltrate, and others being indistinguishable from untreated control cases apart from having an increased number of compound lysosomes in the myoma cell cytoplasm. The degree of cellular shrinkage, measured by nuclear crowding, showed an inverse relationship to the proportion of collagen in the sections but none of the histological variables measured correlated with the degree of uterine shrinkage. It is concluded that the proportion of collagen in the lesions and other factors such as density of estrogen receptors, vascularity, cell proliferation rates, and degree of inflammatory cell infiltration affect the response to GnRH agonist therapy.

Adult↗
PubMed1995

Ovarian 11 beta-hydroxysteroid dehydrogenase activity is inversely related to the outcome of in vitro fertilization-embryo transfer treatment cycles.

OBJECTIVES: To determine the relationship of ovarian 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) activity to the outcome of IVF-ET and to establish whether 11 beta-HSD activities vary for a given patient between consecutive treatment cycles. DESIGN: Retrospective correlation analysis. SETTING: Patients were treated and ovarian 11 beta-HSD activities were measured at independent fertility and biochemistry departments, respectively. PATIENTS: Random series of 137 women undergoing a total of 172 treatment cycles for IVF-ET. INTERVENTIONS: Subcutaneous buserelin acetate plus IM hMG and hCG for controlled ovarian hyperstimulation; blood samples were collected for plasma LH and steroid determinations. MAIN OUTCOME MEASURES: Presence or absence of detectable ovarian 11 beta-HSD activity, oocyte fertilization rates, and the identification of clinical pregnancies. RESULTS: None of the 101 cycles associated with 11 beta-HSD positive granulosa-lutein cells resulted in clinical pregnancies, whereas the pregnancy rate for the 71 patients with undetectable ovarian 11 beta-HSD activity was 63.4% per cycle. The incidence of total fertilization failure was lower and the median oocyte fertilization rate was higher in cycles characterized by 11 beta-HSD-negative cells. Plasma concentrations of LH and E2 were higher in cycles yielding 11 beta-HSD-negative cells, whereas plasma P, patient age, and the number of oocytes retrieved did not relate to ovarian 11 beta-HSD activity. For the 35 patients studied in repeat cycles, ovarian 11 beta-HSD activities did not relate to those in the initial cycles. CONCLUSIONS: Ovarian 11 beta-HSD activity is associated with failure to conceive by IVF-ET. For a given patient, ovarian 11 beta-HSD activity varies between consecutive treatment cycles. Hence, ovarian 11 beta-HSD activities may predict the outcome of this assisted reproduction protocol independently in each treatment cycle.

11-beta-Hydroxysteroid Dehydrogenases↗