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Biomedical subjects

M Lawrence

Publications and source records attributed to M Lawrence.

At least 55 records · Page 3Linked to original sources
PubMed1994

A case of successful use of reproductive technology for a couple with subfertility due to retrograde ejaculation, where artificial insemination had failed.

A case history of a couple where the infertility was due to retrograde ejaculation is presented; when conventional treatment with artificial insemination using sperm isolated from postejaculatory urine failed, IVF and GIFT technology was applied. This resulted in a pregnancy which unfortunately failed at 3 months, unrelated to the method of conception. This case report highlights the possible use of IVF/GIFT for yet another type of male subfertility.

Adult↗
PubMed1994

Eicosanoid production by human aortic endothelial cells in response to endothelin.

Endothelial cells actively regulate their environment by secreting humoral substances, including endothelin-1 and a variety of eicosanoids, that have local actions. To elucidate interactions among these local mediators, we measured release of cyclooxygenase and lipoxygenase pathway products of arachidonate metabolism by human aortic endothelial cells after incubation with endothelin-1. Supernatants were collected, extracted, and fractionated using high-performance liquid chromatography. Radioimmunoassays for eicosanoids were performed on the appropriate fractions. After endothelin stimulation, production of the prostacyclin metabolite 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), the thromboxane (Tx) metabolite TxB2, and prostaglandin E2 (PGE2) were increased (307 +/- 48, 320 +/- 91, and 315 +/- 74% of control, P < 0.05). Leukotriene B4 (LTB4) release was modestly increased (195 +/- 19% of control, P < 0.05). The release of 5-hydroxyeicosatetraenoic acid (5-HETE) was increased (300 +/- 57% of control, P < 0.05); production of 12-HETE and 15-HETE was unchanged. Production of eicosanoids peaked between 30 and 120 min. Preincubation with pertussis toxin prevented increased production of PGE2, LTB4, and 5-HETE after endothelin-1 stimulation; pretreatment with sphingosine had no effect. Interactions between endothelin and eicosanoids may be important components of the complex network that regulates vascular tone, coagulation, and inflammation at the local level.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1994

Nutritional status and early warning of mortality in southern Ethiopia, 1988-1991.

OBJECTIVE: Ethiopian Government guidelines on nutritional survey data and relief provision call for intervention once mean weight-for-length (W/L) in an area falls below 90% of reference, on the basis that mortality is unlikely to rise until this level is reached. In this paper the appropriateness of the 90% cut-off is examined using data from Wolayita, southern Ethiopia. SURVEY DESIGN AND SUBJECTS: Fifteen to 25 villages are selected at random for survey each year, with all children 70-110 cm in length being followed up every 2 months. During the 3 years covered by these analyses 21,701 W/L measurements were made on 5455 children from 65 villages. 126 of the children died. RESULTS: In the first and third survey years, rapid declines in mean W/L were recorded, with mortality increasing very roughly three-fold (compared to year 2, P < 0.01), even though mean W/L remained at or above 90% of reference at all times. A logistic regression analysis relating mortality to W/L indicates that between 20% and 35% of the greater mortality in years 1 and 3 can be explained by the observed changes in W/L. The remainder occurred because of an increase in underlying or background risk (which might perhaps be expected in the circumstances of generally deteriorating nutritional status). CONCLUSIONS: The results suggest that child mortality is likely to increase before area mean W/L falls to 90% of reference, indicating that emergency interventions should be triggered earlier than at present.

Anthropometry↗
PubMed1993

A study of sister chromatid exchange and somatic cell mutation in hospital workers exposed to ethylene oxide.

To investigate the risks of exposure to ethylene oxide (EO) at current permissible levels and at past higher levels, an inception cohort of sterilizer operators and supervisors from the Central Processing Department (CPD), respiratory therapists, and engineers exposed to EO were identified at the McMaster University Medical Centre. A comparison group from Nutrition Services (NUTR) were matched with the CPD workers on the basis of sex, age, and smoking habit. The present report is based on genetic test results for the 94 CPD and matched NUTR workers only. Statistical analysis based on the mean SCE frequency in the top 5, top 10, and all cells (50 cells scored per individual) and high frequency cells (HFC) based on the 95th percentile for nonsmoking control subjects showed a direct association with current smoking but not with EO exposure. Similarly, statistical analysis of the somatic cell mutation (SCMT) variant frequencies did not demonstrate an association with EO exposure, nor with smoking. Regression analysis indicated that sex was the only other covariate that significantly affected SCE. Age was weakly associated with SCMT. A statistically significant interaction between occupational exposure and smoking habits was observed only for the mean SCE frequency of the top 5 and top 10 cells when the 11 current CPD/NUTR pairs were not included. Thus, this interaction should be interpreted with caution.

Ethylene Oxide↗
PubMed1992

Nosocomial transmission of tuberculosis in a hospital unit for HIV-infected patients.

OBJECTIVE: To assess nosocomial transmission of tuberculosis (TB). DESIGN: A historical cohort study of hospitalized patients with the human immunodeficiency virus (HIV) and a purified protein derivative (PPD) tuberculin skin test survey of health care workers (HCWs). SETTING: A large public teaching hospital in San Juan, Puerto Rico. PATIENTS: For the cohort study, a case patient was defined as any patient in the HIV unit at the hospital who developed culture-positive TB from 31 days or more after admission through December 31, 1989. For the PPD survey, of 1420 HCWs from the hospital, 908 agreed to participate and had sufficient data for analysis. MAIN OUTCOME MEASURES: For the cohort study, to compare the risk of developing active TB among patients who were exposed to hospital roommates with infectious TB and the risk among nonexposed patients. For the HCW PPD survey, to determine the prevalence of and risk factors for tuberculous infection. RESULTS: Eight of 48 (9.7/10,000 person-days) exposed case patients vs four of 192 (0.8/10,000 person-days) nonexposed case patients developed active TB (relative risk [RR] = 11; 95% confidence interval [CI], 2.3, 50.3). Positive PPDs (greater than or equal to 10 mm of induration) in HCWs were associated with older age (P = .0001) and with history of community TB exposure (P = .0002). In a multivariable logistic model that adjusted for these variables, HIV unit nurses (nine of 19) and nurses in the internal medicine ward (45 of 90) had a higher proportion of positive PPDs than the reference group (clerical personnel on other floors: 35 of 188, P = .0005). CONCLUSIONS: These data suggest that patient-to-patient transmission of TB in HIV units can occur and that HCWs are at risk of acquiring TB infection.

Adolescent↗
PubMed1992

Body composition of rural Beninese women in different seasons assessed by skinfold thickness and bioelectrical-impedance measurements and by a deuterium oxide dilution technique.

Body composition of 24 rural Beninese women was assessed in a pre- and a postharvest season by using skinfold-thickness measurements, bioelectrical-impedance analysis (BIA), and deuterium oxide (D2O) dilution. Fat mass assessed by D2O dilution was 12.3 +/- 3.3 kg; by skinfold-thickness measurements, 13.8 +/- 3.3 kg; and by BIA, 14.1 +/- 2.9 kg. Fat mass assessed by D2O was significantly lower (P less than 0.05) than fat mass assessed by the other two methods. Body weight in the postharvest season was 0.8 +/- 1.6 kg higher (P less than 0.05) than during the preharvest season. All three methods demonstrated that there were no significant changes in fat mass but that fat-free mass increased significantly (P less than 0.05) from pre- to postharvest season.

Adult↗
PubMed1992

Patient compliance with colorectal cancer screening in general practice.

A randomized controlled trial to test patient compliance with screening for colorectal cancer in association with general practice health checks was carried out in six practices (three urban and three rural). A total of 1588 patients aged 45-64 years were randomized to one of four intervention groups. In the first group patients were posted a Haemoccult test (Kline Beckman) kit. This group was not invited for a health check. In the second group patients were posted the Haemoccult test kit, together with an invitation to attend for a health check. In the third group patients were posted an invitation for a health check, which explained that the patient would be offered the Haemoccult test kit by the nurse at the health check. In the fourth group patients were just invited for a health check. It was found that combining faecal occult blood testing with the health check did not reduce attendance at the health check--43.5% of patients attended when the Haemoccult test kit was offered by the nurse at the health check, 43.6% attended when a test kit was included with the invitation to attend the health check and 42.9% attended when the health check invitation was posted on its own. Overall, compliance with Haemoccult testing was not significantly increased by associating it with a health check (26.2% versus 25.5%) but compliance was higher when the faecal occult blood testing kit was enclosed with the health check invitation than when it was offered at the health check (31.7% versus 20.6%, P less than 0.001). It is easier and cheaper to combine various screening procedures. Although the overall use of the Haemoccult test in the study population was low, there is no reason why the relatively higher compliance rate obtained on posting the test kit with a health check invitation cannot be achieved in previously unscreened populations with higher expected compliance rates. However, faecal occult blood screening for colorectal cancer should not be undertaken on a population basis until its effectiveness in reducing mortality has been proven by randomized trial.

Colonic Neoplasms↗
PubMed1991

Auditing audits: the method of Oxfordshire Medical Audit Advisory Group.

OBJECTIVES: To develop a systematic method for both summative and formative audit of practice audits, and to use the method to review Oxfordshire practice audits and to plan improvement. DESIGN: Development of a coding system for the audit cycle subsequently used prospectively to assess audits reported to medical audit advisory group coordinators on practice visits. SETTING: All 85 general practices in Oxfordshire, of which 80 were visited by Oxfordshire Medical Audit Advisory Group coordinators. MAIN OUTCOME MEASURES: Satisfaction of criteria for different levels of audit (full, partial, potential, planning or no audit) according to coding scores for practice audits. RESULTS: 46 (58%) practices were classified as doing audit, the remainder doing no audit or only collecting data for family health services authority returns. Of audits being undertaken, 55/102 (54%) included planning care or the setting of targets. CONCLUSIONS: The coding system offers the prospect of formative assessment for practices to help them improve their audits, and summative assessment for the family health services authority to satisfy the needs for professional accountability. Its use in Oxfordshire disclosed considerable deficiencies in the process of practice audit. IMPLICATIONS AND ACTION: Practices in Oxfordshire should improve their audits. The advisory groups target to March 1992 is for 50% of practices to be doing full or partial and 25% potential audit and half of the remainder planning audit. Practices are encouraged to include in their audit implementing change, planning care, and agreeing criteria for further assessment.

England↗
PubMed1991

Multiple integrins share the ability to induce elevation of intracellular pH.

Previous work has shown that adhesion of anchorage-dependent cells to fibronectin via integrin alpha 5 beta 1 leads to activation of the Na-H antiporter and a rise in intracellular pH (pHi). We now show that adhesion of bovine capillary endothelial cells (BCE) to fibrinogen; collagens type III, IV, and V; laminin; and vitronectin; ligands that bind other members of the integrin family, resulted in significant elevations in pHi. Other ligands (basic fibroblast growth factor, concanavalin A, and thrombin), which bind cells when immobilized on plastic, but that do not bind integrins and do not support cell growth, do not elevate pHi. Adhesion to an antibody against integrin alpha v beta 3 also elevates pHi. Adhesion of peripheral human T lymphocytes to an antibody against the integrin LFA-1 induced a rise in pHi. Antibodies to CD2 or ICAM-2 had only slight effects on pHi, whereas an antibody to the T cell receptor complex that strongly activates T cells induced a large increase in pHi. We conclude that elevation of pHi by integrins is specific and is a property shared by many members of the integrin family.

Animals↗
PubMed1991

Preparation of monoclonal antibodies to the beta A subunit of ovarian inhibin using a synthetic peptide immunogen.

Seven different synthetic peptides were prepared corresponding to regions of the beta A subunit of 32 KDa human ovarian inhibin predicted to contain possible continuous B cell epitopes. These were coupled to tuberculin as a carrier and used to immunize mice previously given a priming dose of human tuberculosis vaccine. Only one of these peptides, corresponding to sequence 82-114, consistently gave good titres of antibodies reactive with intact 32 KDa bovine inhibin by ELISA. From one of the mice immunized with this peptide, six stable hybridomas were prepared. Five of these secreted an IgM and the sixth (clone E4) secreted an IgG2b antibody. Immunoblotting experiments on follicular fluid concentrates, after treatment with sodium dodecyl sulphate and mercaptoethanol, showed strong reactivity of the antibody from clone E4 only with bands of about 13 kDa and 58 kDa corresponding to forms of the beta A subunit previously described. This monoclonal antibody, and an antibody to the alpha subunit previously made in this laboratory using synthetic peptides, should prove useful reagents for further study of inhibins and activins.

Amino Acid Sequence↗
PubMed1991

Early gastric cancer. Twenty-eight-year experience.

A retrospective study of early gastric cancer (60 patients) was performed to evaluate its diagnosis and treatment. Ninety-five per cent of patients presented with nonspecific gastrointestinal symptoms and 53.3% had been treated for presumed benign disease for up to 48 months before diagnosis. Fiberoptic endoscopy detected these lesions more accurately than radiologic examination. The disease-free 5-year survival rate after resection was 76.4%. Survival showed no significant correlation with sex, tumor site, macroscopic appearance, extent of gastric resection, or histopathologic type. Tumors larger than 1.5 cm in diameter, invasion of submucosa, or lymph node metastasis resulted in significantly lower survival rates. Three of eight patients with nodal metastasis survived 5 or more years, including one who had second-echelon deposits. A high index of suspicion may permit more frequent detection. Extended lymphadenectomy (R2) is recommended to achieve the highest possible cure rate.

Adenocarcinoma↗
PubMed1991

Women who gain more fat during pregnancy may not have bigger babies: implications for recommended weight gain during pregnancy.

The correlation between infant birthweight and the amount of fat gained during pregnancy (estimated as the change in maternal weight between 10 weeks gestation and 2-3 weeks postpartum) was studied in 115 healthy, parous, urban Scottish housewives. There was very little correlation between these variables (r = 0.13, falling to r = 0.07 after birthweight was adjusted for initial maternal weight and length of gestation), i.e., women who gained more fat during their pregnancies did not give birth to heavier babies. This suggests that for most women one of the principal effects of increasing food intake during pregnancy may be to increase maternal fat gain rather than promote fetal growth, and that efforts to increase birthweight by encouraging greater weight gain during pregnancy may be unsuccessful.

Adult↗
PubMed1991

A comparison of physical activity in Gambian and UK children aged 6-18 months.

The activity patterns of 81 Gambian and 53 UK children aged six, 12 or 18 months were compared by means of an activity diary technique. Major differences between communities were observed in the duration of play (2-3 times longer in UK compared to Gambian children) and in the duration of vigorous activities such as crawling, walking and running (2-4 times longer duration in the UK compared to the The Gambia). To investigate whether the lower activity of Gambian children could be explained by differences in nutritional or health status, subgroups of Gambian children were compared. Only small differences in activity pattern were found between Gambian children above and below 80% weight for age and between Gambian children who were or were not diagnosed ill within 10 days of study, suggesting that other factors (e.g. socio-cultural differences or the absence of conventional toys) may explain the lower activity of Gambian compared to UK children.

Analysis of Variance↗