Search PubMed⌕ Search

Biomedical subjects

B Luke

Publications and source records attributed to B Luke.

At least 19 recordsLinked to original sources
PubMed2005

Discrimination of isolates of Mycobacterium bovis in Northern Ireland on the basis of variable numbers of tandem repeats (VNTRs).

The ability to reproducibly discriminate Mycobacterium bovis isolates and trace their transmission has the potential to clarify sources of infection and major routes of transmission for bovine tuberculosis (TB). A PCR-based genotyping assay has been developed to discriminate between strains of M bovis by examining multiple sites in its genome that consist of variable numbers of tandem repeats (VNTRS). The discriminatory power and reproducibility of this VNTR typing has been compared with that of the established PCR-based spoligotyping technique by using a panel of 461 isolates of M bovis prevalent in Northern Ireland. The VNTR assay discriminated 40 different profiles, the most prevalent of which constituted 21 per cent of the total, compared with 14 profiles discriminated by spoligotyping, the most prevalent of which constituted 65 per cent. No significant differences were observed between the prevalences of the VNTR profiles in the years from 1999 to 2003. A preliminary evaluation indicated that most genotypes predominated in particular areas of the country. This VTNR typing assay was found to be highly discriminating, with the performance characteristics to support its systematic application to the molecular epidemiology of bovine TB.

Animals↗
PubMed2005

Development of a total quality system for transfusion medicine services in Ontario hospitals.

TOTAL QUALITY SYSTEM: The purpose of the project was to develop a total quality system in Transfusion Medicine which would serve as a model for development of a provincial transfusion quality system. Pilot studies were carried out in Ottawa and Hamilton/Niagara. Each region was provided with resources to create a Quality Team. The Quality Team was comprised of several individuals including a Quality Team Leader, and a number of Quality Assistants. The responsibilities of the Quality Team included: working with Transfusion Medicine Laboratories in area hospitals to achieve a total quality system, identification, standardization and implementation of 'best transfusion practices' throughout the regional hospitals, development and implementation of standard operating procedures (SOP) based on best practices, development and implementation of transfusion/administration guidelines, assessment of blood utilization, education, training, non-conformance (error) management, and surveillance. Liaison was also established with the co-coordinator for the Transfusion Co-coordinator's Project (ONTRAC), the education coordinator for the Sunnybrook Project, the Public Health Agency of Canada, Quality Management Practice-Laboratory System, the Ontario Hospital Association and Laboratory Licensing. In Ottawa these activities resulted in the development of:

Blood Banks↗
PubMed2004

Birth weight references for triplets.

OBJECTIVE: The purpose of this study was to formulate growth references that reflect triplet fetal and neonatal populations at each gestational age by combining serial ultrasonographic estimates of fetal weights and measured birth weights. STUDY DESIGN: This historical cohort study was based on 188 pregnancies of live-born triplets of > or =23 weeks' gestation. Ultrasonographic fetal weight measures were modeled as a function of gestational age for each infant. Linear regression models were used to fit the data, and weight percentiles were generated. RESULTS: Well-grown triplets fell substantially below singletons by 30 weeks and twins after 34 weeks. Trichorionic vs monochorionic or dichorionic placentation resulted in 27% higher growth at the 10th %ile, 5% higher growth at the 50th %ile, and 4% higher growth at the 90th %ile by 34 weeks. CONCLUSION: The overall pattern of fetal growth for well-grown triplets does not differ from that of singletons and twins until late gestation, confirming that, in utero, well-grown children have similar growth potentials, regardless of plurality.

Birth Weight↗
PubMed2000

Working conditions and adverse pregnancy outcome: a meta-analysis.

OBJECTIVE: To evaluate the association between working conditions and adverse pregnancy outcomes by performing a meta-analysis of published studies. DATA SOURCES: We searched the English-language literature in MEDLINE through August 1999 using the terms standing, posture, work, workload, working conditions, shift, occupational exposure, occupational diseases, lifting, pregnancy complications, pregnancy, small for gestational age (SGA), fetal growth retardation (FGR), preterm, and labor. METHODS OF STUDY SELECTION: We included observational studies evaluating the effect of one or more of the following work-related exposures on adverse pregnancy outcome: physically demanding work, prolonged standing, long work hours, shift work, and cumulative work fatigue score. Outcomes of interest were preterm birth, hypertension or preeclampsia, and SGA.We conducted a meta-analysis based on 160,988 women in 29 studies to evaluate the association of physically demanding work, prolonged standing, long working hours, shift work, and cumulative work fatigue score with preterm birth. Also analyzed were the associations of physically demanding work with hypertension or preeclampsia and SGA infants. The data were analyzed using the Peto-modified Mantel-Haenszel method to estimate the pooled odds ratios (ORs) and 95% confidence intervals (CIs). TABULATION, INTEGRATION, AND RESULTS: Physically demanding work was significantly associated with preterm birth (OR 1.22, 95% CI 1.16, 1. 29), SGA (OR 1.37, 95% CI 1.30, 1.44), and hypertension or preeclampsia (OR 1.60, 95% CI 1.30, 1.96). Other occupational exposures significantly associated with preterm birth included prolonged standing (OR 1.26, 95% CI 1.13, 1.40), shift and night work (OR 1.24, 95% CI 1.06, 1.46), and high cumulative work fatigue score (OR 1.63, 95% CI 1.33, 1.98). We found no significant association between long work hours and preterm birth (OR 1.03, 95% CI 0.92, 1.16). CONCLUSION: Physically demanding work may significantly increase a woman's risk of adverse pregnancy outcome.

Female↗
PubMed2000

Birth weight references for twins.

OBJECTIVE: We sought to formulate fetal and birth weight references for twins from longitudinal data. STUDY DESIGN: This historic cohort study was based on 1831 pregnancies of twins born alive at >/=28 weeks' gestation from Baltimore, Maryland; Miami, Florida; Charleston, South Carolina; and Ann Arbor, Michigan. RESULTS: When we compared singletons and twins, the percentiles of twins fell substantially below the 10th percentile of singletons by 28 weeks' gestation, below the 50th percentile by 30 weeks' gestation, and below the 90th percentile by 34 weeks' gestation. The difference at the 50th percentile was 147 g (10%) at 30 weeks' gestation, 242 g (14%) at 32 weeks' gestation, 347 g (17%) at 34 weeks' gestation, 450 g (19%) at 36 weeks' gestation, 579 g (22%) at 38 weeks' gestation, and 772 g (27%) at 40 weeks' gestation. CONCLUSION: This new reference demonstrates that, although the overall pattern of fetal growth is slower for twins versus singletons from about 30 weeks' gestation, well-grown twins and singletons do not differ as much as previously believed.

Adult↗
PubMed2000

An analysis of a preoperative pediatric autologous blood donation program.

OBJECTIVE: To determine the efficacy of a pediatric autologous blood donation program. DESIGN: A retrospective study of patient charts and blood-bank records. SETTING: The Children's Hospital of Eastern Ontario, Ottawa, a tertiary care, pediatric centre. PATIENTS: One hundred and seventy-three children who received blood transfusions for a total of 182 procedures between June 1987 and June 1997. INTERVENTIONS: Autologous and homologous blood transfusion required for major surgical intervention, primarily spinal fusion. MAIN OUTCOME MEASURES: Surgeons' accuracy in predicting the number of autologous blood units required for a given procedure, compliance rate (children's ability to donate the requested volume of blood), utilization rate of autologous units and rate of allogeneic transfusion. RESULTS: The surgeons' accuracy in predicting the number of autologous units required for a given procedure was 53.8%. The compliance rate of children to donate the requested amount of blood was 80.3%. In children below the standard age and weight criteria for blood donation the compliance rate was 75.5%. The utilization rate of autologous units obtained was 84.4% and the incidence of allogeneic transfusion was 26.6%. CONCLUSIONS: There was a high rate of compliance and utilization of predonated autologous blood in the children in the study. Preoperative blood donation programs are safe and effective in children, even in those below the standard age and weight criteria of 10 years and 40 kg.

Adolescent↗
PubMed1999

Work and pregnancy: the role of fatigue and the "second shift" on antenatal morbidity.

OBJECTIVE: This study was undertaken to evaluate factors at home and work associated with antenatal morbidity (emergency department visits and hospitalizations) among employed pregnant women. STUDY DESIGN: This prospective study of 213 women included 3 antenatal interviews at about 16, 24, and 30 weeks' gestation with questions on health history, lifestyle, housework, working conditions, and emergency department visits and hospitalizations. Work scores and home scores were formulated from each interview. Fatigue was defined as being very tired or extremely tired at the end of a typical workday. The risk of antenatal morbidity was modeled by means of logistic regression; results are presented as adjusted odds ratios with 95% confidence intervals. RESULTS: The risk of antenatal morbidity, which was greatest during the second trimester, was increased by stress (adjusted odds ratio, 2.45; 95% confidence interval, 1.32-4.57), fatigue (adjusted odds ratio, 3.77; 95% confidence interval, 1.98-7.18), work plus home score (adjusted odds ratio, 1.55; 95% confidence interval, 1.22-1.97), and the interaction of fatigue and work plus home score (adjusted odds ratio, 4.61; 95% confidence interval, 2.02-10.50). CONCLUSIONS: These findings suggest that maternal fatigue contributes significantly to antenatal morbidity.

Adult↗
PubMed1998

The influence of desmopressin on blood loss during spinal fusion surgery in neuromuscular patients.

STUDY DESIGN: A double-blind study comparing the effects of desmopressin and a placebo (normal saline) on blood loss during spinal instrumentation for neuromuscular scoliosis. OBJECTIVE: To determine the effectiveness of desmopressin acetate (DDAVP) in reducing operative blood loss in hemostatically normal patients undergoing spinal fusion surgery for neuromuscular scoliosis. SUMMARY OF BACKGROUND DATA: Desmopressin acetate has been shown to improve bleeding times and to provide surgical hemostasis in patients with platelet disorders. Its effect in reducing bleeding times in normal patients has been the subject of debate in several surgical specialties. Recent observations that DDAVP seems to reduce bleeding times and blood loss in patients undergoing spinal surgery for neuromuscular scoliosis warranted a more focused analysis on its role in this surgical procedure. METHODS: Patients undergoing surgery for neuromuscular scoliosis were randomly assigned to receive DDAVP or placebo. Bleeding times and plasma clotting factors were measured before the administration of the DDAVP or placebo and 60 minutes after. Operative blood loss was carefully measured. RESULTS: Although the administration of DDAVP decreased overall blood loss by an average of 19% compared with blood loss in the placebo group and blood loss per vertebra fused by an average of 15%, these results were not statistically significant. CONCLUSIONS: Bleeding time and blood loss seem to respond better to DDAVP in some patients, in whom significant decreases were observed, than they do in others. The problem is in identifying those patients in whom a decrease in bleeding time will be elicited after administration of DDAVP. Preoperative administration of DDAVP to such patients should significantly decrease operative blood loss.

Adolescent↗
PubMed1998

The importance of early weight gain in the intrauterine growth and birth weight of twins.

OBJECTIVE: It was our objective to evaluate the association between early maternal weight gain (before 20 weeks), midpregnancy weight gain (20-28 weeks), and late pregnancy weight gain (28 weeks to birth) with fetal growth and birth weight in twins. STUDY DESIGN: This historic cohort study was based on 1564 births of live twins >/=28 weeks' gestation from Baltimore, Maryland, Miami, Florida, Charleston, South Carolina, and Ann Arbor, Michigan. RESULTS: Early fetal growth was affected only by smoking and chorionicity. Factors in models of both mid and late fetal growth included maternal age, pregravid weight, parity, rates of early pregnancy and midpregnancy maternal weight gain, smoking, and pre-eclampsia. Increased midpregnancy fetal growth was associated with early maternal weight gain (10.91 g/wk per pound per week) and midpregnancy maternal weight gain (15.89 g/wk per pound per week). Increased late fetal growth was associated with early maternal weight gain (16.86 g/wk per pound per week) and midpregnancy maternal weight gain (23.88 g/wk per pound per week). Increased birth weight was associated with early (283.02 g per pound per week), mid (163.58 g per pound per week), and late (69.76 g per pound per week) maternal weight gains. CONCLUSIONS: These findings confirm the importance of early maternal weight gain in twin fetal growth and birth weight.

Adult↗
PubMed1997

Critical periods of maternal weight gain: effect on twin birth weight.

OBJECTIVE: Our purpose was to evaluate the association between maternal weight gain and twin birth weight. STUDY DESIGN: This historic cohort study was based on 646 live-born twin births of > or = 28 weeks from Baltimore, Maryland, Miami, Florida, and Ann Arbor, Michigan. The sum of twin-pair birth weight was modeled as a function of either net maternal weight at delivery or rates of maternal weight gain with use of multiple regression. RESULTS: Birth weight was significantly associated with weight gain before 20 weeks in underweight women, before 20 weeks and after 28 weeks in overweight women, and during all three gestational periods in normal-weight women. Weight gain before 20 weeks had the largest effect on infants of underweight women, less of an effect on infants of normal-weight women, and half as much effect on infants of overweight women. Weight gain after 28 weeks significantly affected the infant birth weights of normal-weight and overweight women, but the effect was half as great among infants of the latter group. CONCLUSIONS: These findings suggest that weight gain during critical periods of gestation significantly influences twin birth weight; these critical periods vary by maternal pregravid weight status.

Adult↗
PubMed1997

Maternal nutrition in twin gestations: weight gain, cravings and aversions, and sources of nutrition advice.

BACKGROUND: Maternal nutrition has a strong influence on singleton and twin birthweight. This study evaluated the association between twin birthweight and maternal pregravid body mass index (BMI), weight gain, and cravings and aversions. Information was also obtained regarding sources of nutrition advice and advised versus actual weight gain. METHODS: This study is based on data from interviews with 928 mothers of twins. Univariate analysis included comparisons by source of nutritional advice, birthweight categories, and categories of cravings and aversions. Multiple logistic regression was used to formulate models for mean twin birthweights > 1,500 g and > 2,500 g. RESULTS: Mothers who received their nutrition advice from a registered dietitian had the highest weight gains and the lowest proportion of birthweights < 1,500 g. For mean twin birthweight > 2,500 g, the final model included prematurity, pregravid BMI, and weight gain; for birthweights > 1,500 g, the model additionally included maternal age and aversions. CONCLUSIONS: Maternal pregravid BMI and gestational weight gain were shown to be important factors influencing twin birthweight. Nutrition advice, particularly from a registered dietitian, may be vital in assuring adequate weight gain, and therefore better birthweights, for these high-risk pregnancies.

Birth Weight↗
PubMed1996

Reducing fetal deaths in multiple births: optimal birthweights and gestational ages for infants of twin and triplet births.

The objective of this study was to determine the birthweight and gestational age associated with the lowest fetal mortality for twins and triplets. The study design was a population-based analysis of all live births and fetal deaths in the US between 1983-88. Fetal mortality was compared by categories of birthweight and gestational age, for twins and triplets versus singletons, and within each plurality by the lowest rate compared to all other rates as relative risks +/- 95% Cls. The overall versus lowest fetal death rate per 1,000 conceptions for singletons was 4.3 versus 0.9 at 3700-4000 g and 40-41 weeks; for twins, 15.5 versus 3.3 at 2500-2800 g and 36-37 weeks; and for triplets, 21.0 versus 5.2 at 1900-2200 g at 34-35 weeks. Beyond these plurality-specific lowest ranges, the risk of fetal death increased, more for twins than singletons, and most for triplets. To conclude, fetal death rates can be reduced by 75-80% with attainment of birthweight and gestational age within a plurality-specific ideal range.

Birth Weight↗
PubMed1996

The cost of prematurity: a case-control study of twins vs singletons.

OBJECTIVES: This study evaluated the extent to which morbidity and costs at birth were associated with plurality, gestational age, and birth-weight with a sample of twins from a large urban hospital. METHODS: Each twin infant was matched to two singleton infants (control [ctrl]-singletons) for payor status and race, and to one singleton infant (gestation [ga]-singleton) for payor status, race, and gestational age; after exclusion of infants who were transferred, the study population included 111 twins, 242 ctrl-singletons, and 106 ga-singletons. Data were stratified by five gestational categories and compared across study groups. Outcomes included birthweight, neonatal diagnoses, infant length of stay, infant costs per day, and total infant and total birth costs. RESULTS: Total birth costs ranged from $280,146 at 25 to 27 weeks to $9,803 at 39 to 42 weeks, decreasing with advancing gestation to means of $88,891 (twins), $43,041 (ga-singletons), and $9,326 (ctrl-singletons). Twins did not differ from either group of singletons in prematurity-related diagnoses, length of stay, or costs until after 34 weeks' gestation. CONCLUSIONS: In this sample, prematurity, not plurality, was the predominant cost factor at birth. Compared with singletons, twins experienced increased morbidity and associated costs after 38 weeks' gestation.

Birth Weight↗
PubMed1995

The association between occupational factors and preterm birth: a United States nurses' study. Research Committee of the Association of Women's Health, Obstetric, and Neonatal Nurses.

OBJECTIVE: Our purpose was to evaluate factors associated with preterm birth among a national sample of U.S. nurses. STUDY DESIGN: We conducted a case-control study of 210 nurses whose infants were delivered prematurely (< 37 weeks) (cases) and 1260 nurses whose infants were delivered at term (> or = 37 weeks) (controls). An occupational fatigue score was constructed from four sources and varied from 0 to 4. The relation between occupational activity (including hours working and fatigue score) and preterm birth was analyzed with the use of Pearson chi 2 tests, estimates of odds ratios with 95% confidence intervals, and multivariate logistic regression; we controlled for confounding factors. RESULTS: Factors significantly associated with preterm birth included hours worked per week (p < 0.002), per shift (p < 0.001), and while standing (p < 0.001); noise (p = 0.005); physical exertion (p = 0.01); and occupational fatigue score (p < 0.002). The adjusted odds ratios were 1.6 (p = 0.006) for hours worked per week (< or = 36 vs > 36) and 1.4 (p = 0.02) for fatigue score < 3 vs > or = 3. CONCLUSIONS: Preterm birth among working women may be related to hours worked per day or week and to adverse working conditions.

Case-Control Studies↗