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Biomedical subjects

B Abrams

Publications and source records attributed to B Abrams.

At least 37 records · Page 2Linked to original sources
PubMed1997

The pattern of maternal weight gain in women with good pregnancy outcomes.

OBJECTIVES: This study describes the pattern of maternal weight gain in women with good pregnancy outcomes and provides data to fill in the provisional weight-gain charts published by the Institute of Medicine (IOM) in 1990. METHODS: We selected 7002 women with good outcomes (defined by factors related to maternal and infant health) from the University of California, San Francisco, Perinatal Database. For each body mass index category, we compared percentiles of weight gain by trimester in women who achieved the IOM recommendations for total gain and those who did not. RESULTS: Trimester rates of gain varied by body mass index category and exceeded IOM guidelines in all groups. Forty percent of these women with good outcomes had total gains within the guidelines and provided data to complete the IOM weight-gain charts. CONCLUSIONS: Most women in this good-outcome sample would have been suspected of being at increased risk for poor outcome on the basis of their weight gain. This confirms the IOM recommendation that evaluation of the underlying causes of excessively high or low weight gain during pregnancy is necessary before appropriate interventions can be applied.

Adult↗
PubMed1996

Use of a high affinity DNA ligand in flow cytometry.

To investigate the feasibility of using oligonucleotides in flow cytometry we describe a model system consisting of human neutrophil elastase (HNE) coated on 3.3 micro beads and a high affinity DNA ligand for HNE isolated by in vitro selection (SELEX). In this system the fluoresceinated DNA ligand was equally effective as an anti- HNE antibody in detecting HNE on beads. The location on and the chemistry of attachment of fluorescein to the DNA ligand is critical for the sensitivity of detection. DNA constructs in which fluorescein was conjugated via an ethylene glycol tether to either the 5'-end or near the 3'-end gave much higher signals than did probes with fluorescein directly conjugated to either end. Second-step staining with strepavidin-conjugated phycoerythrin was accomplished using a biotinylated DNA ligand in the initial staining of HNE beads. These data suggest that instead of, or in addition to, antibodies high affinity oligonucleotide probes can be useful in diagnostic applications based on flow cytometry.

Animals↗
PubMed1996

Analysing the relationship between maternal weight gain and birthweight: exploration of four statistical issues.

Four statistical issues concerning the analysis of birthweight and maternal weight gain during pregnancy are discussed: (1) Part-whole correlation is described (e.g. the correlation between total maternal weight gain and her infant's birthweight). (2) The choice between a ratio or two separate explanatory variables is explored (e.g. body mass index or using maternal weight and height separately). (3) Two statistical properties (bias and power) when a binary variable replaces a continuous variable are discussed (e.g. consequences of using low birthweight instead of reported birthweight). (4) A model selection procedure is presented to provide a way to select a useful subset of variables from a large number of available explanatory variables to model an outcome variable (e.g. birthweight). These issues are illustrated with a set of 4017 births from Moffitt Hospital at the University of California, San Francisco. Furthermore, these four issues arise in a number of applications of statistical methods to data collected to study the epidemiology of newborn infants.

Bias↗
PubMed1995

Maternal weight gain pattern and birth weight.

OBJECTIVES: To determine the relationship between maternal weight gain pattern and birth weight. METHODS: All nonobese, white women delivered at the University of California, San Francisco, between 1980-1990 were eligible for this study. Our study group included 2994 uncomplicated pregnancies with complete data. All recorded prenatal weight gain measurements were used to estimate maternal trimester weight gain, pattern of gain (based on low versus not-low gain at each trimester), and total gain at delivery. Multiple linear regression analysis was used to assess the relationship between these weight gain measurements and fetal birth weight. RESULTS: After adjustment for seven covariates, each kilogram of maternal gain in the first, second, and third trimesters was associated with statistically significant increases in fetal birth weight of 18.0, 32.8, and 17.0 g, respectively. When compared with the pattern of gain that was not low in any trimester, patterns with low gain in the first and second trimesters or in the second and third trimesters were associated with significant decreases in birth weights of 133.0 and 88.5 g, but no important change in birth weight was seen for the group whose gains were low in the first and third trimesters. These findings were not due to differences in total weight gain, which averaged approximately 11 kg in these three pattern groups. CONCLUSION: The results suggest that specific patterns of maternal weight gain, particularly weight gain during the second trimester, are related to fetal birth weight.

Adult↗
PubMed1995

Factors associated with the pattern of maternal weight gain during pregnancy.

OBJECTIVE: To examine the pattern of maternal weight gain using maternal characteristics and pregnancy outcome. METHODS: We used maternal weight data measured prospectively from all deliveries between 1980-1990 at the University of California, San Francisco. Piecewise linear regression was used to estimate the rate of maternal weight gain in each trimester. Bivariate techniques were used to examine associations between maternal weight gain per trimester and maternal characteristics and pregnancy outcomes. We also used multiple regression analysis to examine the relationship between maternal characteristics and trimester weight gain. RESULTS: Weight data for at least one trimester were available for 10,418 women. The average rate of weight gain (kg/week) was lowest during the first trimester (0.169 +/- 0.268, n = 7587), peaked during the second trimester (0.563 +/- 0.236, n = 8000), and slowed slightly in the third trimester (0.518 +/- 0.234, n = 10,052). Maternal height, hypertension, cesarean delivery, and fetal size correlated positively with the rate of gain in each trimester, but pre-pregnancy body size, age, parity, smoking status, race-ethnicity, and diabetes were associated differently with gain, depending on which trimester was examined. The most important maternal predictors of weight gain per trimester were age and Asian race-ethnicity in the first trimester; pre-pregnancy body mass, parity, and height in the second; and hypertension, age, and parity in the third. CONCLUSION: Maternal weight gain per trimester is associated with a number of maternal characteristics and pregnancy outcomes, and these relationships vary according to which trimester is being examined.

Adult↗
PubMed1995

Dietary intake among Mexican-American women: generational differences and a comparison with white non-Hispanic women.

OBJECTIVES: Although Mexican Americans consume diets that may protect them against adverse health, dietary advantages may disappear with increased acculturation. This study examined whether the nutrient intake of second-generation Mexican-American women of childbearing age deteriorates compared with that of first-generation Mexican-American women and approximates that of White non-Hispanic women. METHODS: Data on the absolute and relative intake of eight nutrients were obtained from a 24-hour recall and compared among 475 first-generation and 898 second-generation Mexican-American women, and among 2326 White non-Hispanic women. RESULTS: Although first-generation Mexican-American women were of lower socioeconomic status than were second-generation or White non-Hispanic women, they had a higher average intake of protein; vitamins A, C, and folic acid; and calcium than the other two groups. Whereas the mean adequacy ratio of the eight nutrients studied was highest in first-generation Mexican women, it was lowest in their second-generation counterparts. CONCLUSIONS: First-generation Mexican women stand a markedly lower risk of eating a poor diet than second-generation Mexican women, whose nutrient intake resembles that of White non-Hispanic women.

Acculturation↗
PubMed1994

Weight gain and energy intake during pregnancy.

The ideal weight gain or energy intake for an individual woman cannot be determined from research studies. Current guidelines for maternal gain, however, combined with individualized assessment and follow-up, can provide the clinician and the pregnant women with a meaningful target and plan for achieving a healthy weight gain. For some women, increased amounts of maternal weight gain may improve fetal growth prenatally and therefore improve fetal health. For other women, high gains, or even gains within the recommended range, may enhance fetal growth to the point where labor complications, operative deliveries, permanent maternal obesity, and other health problems may occur. Balancing the health benefits and risks of maternal weight gain is a challenge that we will continue to face in the future.

Adolescent↗
PubMed1993

Vitamin and mineral status of women of childbearing potential.

Increasing data suggest a role for micronutrients in pregnancy outcome, and in some cases nutritional status must be adequate in the first weeks of pregnancy. We examined nationally representative survey data on women of childbearing age: the NHANES II data for serum measures of iron status and the CSFII four-day data for dietary measures of intake of protein, iron, zinc, folic acid, and vitamins A, C, and B6. For those nutrients, women below or near poverty had consistently lower levels, with median intakes below the RDA for all but protein (e.g., folic acid, 150 micrograms in contrast with the RDA of 180 for nonpregnant and 400 for pregnant women; for B6, 0.96 mg instead of 1.6 or 2.2). Even among women with incomes as high as three times the poverty level or more, large segments of the population had very low intakes. For example, the 25th percentile in that group was only 142 micrograms/day of folic acid, 4.6 alpha-tocopherol equivalents of vitamin E, 6.7 mg zinc, and 433 mg of calcium. Approximately 15% of women had low transferrin saturation.

Adolescent↗
PubMed1993

Supportive nurse-midwife care is associated with a reduced incidence of cesarean section.

OBJECTIVE: Our purpose was to examine whether care by a certified nurse-midwife, including personal labor support, was associated with a reduced risk of cesarean delivery. STUDY DESIGN: A retrospective cohort study comparing 3551 physician-managed patients with 1056 certified nurse-midwife-managed patients in a university hospital with a mixed socioeconomic and ethnic population was performed. Regression analysis was used to estimate the risk of labor abnormalities, diagnosis of fetal distress, and cesarean delivery in patients delivered by a certified nurse-midwife vs a physician and to control for maternal age, race, parity, fetal size, and delivery year. Subjects included were women having at least five prenatal visits who were delivered of term, singleton, liveborn infants without congenital anomalies with occiput presentation. RESULTS: Odds ratio for cesarean section for women delivered by certified nurse-midwives versus those delivered by physicians was 0.71 (95% confidence interval 0.55, 0.91). Midwifery care was associated with a lower risk of abnormal labor (adjusted odds ratio 0.70, 95% confidence interval 0.60, 0.83) and diagnosis of fetal distress (adjusted odds ratio 0.50, 95% confidence interval 0.32, 0.77). CONCLUSION: This work demonstrates that labor abnormalities and diagnosis of fetal distress are less frequent in patients cared for by nurse-midwives, and there is an association with a lower incidence of cesarean section.

Adult↗
PubMed1993

A prospective study of dietary intake and acquired immune deficiency syndrome in HIV-seropositive homosexual men.

We prospectively studied the relationship between dietary intake at baseline and the development of AIDS over 6 years in a population-based sample of 296 human immunodeficiency virus (HIV)-seropositive men. Nutrient intake was assessed before HIV serostatus was known. Subjects diagnosed with AIDS at baseline or during the 1st year were excluded. After adjustment for baseline CD4 T-lymphocyte count, HIV symptoms, and other risk factors, no nutrients were significantly associated with AIDS. However, when the continuous CD4 count and HIV symptom variables were replaced with a single binary health status variable, the hazard of AIDS decreased as consumption increased for all 11 micronutrients; this relationship was statistically significant for iron, vitamin E, and riboflavin and approached significance for vitamins C, thiamine, and niacin. Higher intake of all 11 micronutrients was associated with higher CD4 counts at baseline, and was significantly so for six of them. Daily multivitamin use was associated with a reduced hazard of AIDS [hazard ratio (HR) = 0.7; 95% confidence interval (CI) = 0.5, 1.0] and a significantly reduced risk for low CD4 counts at baseline (HR = 0.6, 95% CI = 0.4, 0.9). Additional studies are needed to determine whether dietary intake modifies the rate of developing AIDS in those who are HIV seropositive.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Differences in postpartum weight retention between black and white mothers.

OBJECTIVE: To determine whether the overall retention of weight gained during pregnancy and the factors affecting postpartum weight retention differ by race. METHODS: Data from the 1988 National Maternal and Infant Health Survey were analyzed to examine postpartum weight retention of 20 lb or more among 990 black and 1129 white women who began pregnancy with normal weight for height. The impact of various maternal characteristics on both weight retention and the association between weight retention and race was tested by multivariate methods. RESULTS: Black mothers were twice as likely to retain at least 20 lb than white mothers (adjusted odds ratio 2.20, 95% confidence interval 1.50-3.22). This black-white difference did not differ substantially by socioeconomic status. However, many factors affecting postpartum weight retention differed by maternal race. For example, whereas unmarried status was associated with weight retention among white mothers, high parity was associated with weight retention among black mothers. Low socioeconomic status and high prenatal weight gain were associated with an increased risk of weight retention for both black and white mothers. CONCLUSION: These data suggest that population-specific strategies may be needed to help mothers return to their pre-pregnancy weight.

Adult↗
PubMed1992

Lactate measured in diluted and undiluted whole blood and plasma: comparison of methods and effect of hematocrit.

We evaluated a new analyzer that measures lactate in undiluted whole blood by direct (or undiluted) amperometry [Nova Stat Profile 7 Analyzer (SP7); Nova Biomedical, Waltham, MA] by comparing it with two other analyzers, one for measuring lactate in whole blood by indirect (or diluted) amperometry [Model 2300; Yellow Springs Instrument Co. (YSI), Yellow Springs, OH] and another for measuring lactate in plasma by enzymatic colorimetry (aca; Du Pont Co., Wilmington, DE). All between-method comparisons of the three methods showed that the results for plasma were comparable (Sy/x = 0.24-0.33 mmol/L). Within-method comparisons by the YSI differed substantially between plasma and whole blood (Sy/x = 0.48 mmol/L), but within-method comparisons by the SP7 produced better agreement between plasma and whole blood (Sy/x = 0.18 mmol/L). The difference between whole blood and plasma by YSI is related to hematocrit, with the greatest differences noted for samples with the highest hematocrit. Serum lactate measured by SP7 had between-day imprecision (CV) ranging from 12% at 0.5 mmol/L to 4.2% at 3.7 mmol/L, showed a linear standard curve to at least 11.5 mmol/L, and was independent of hematocrit. There was a mean bias of approximately 0.4 mmol/L for results in the reference range for both plasma and whole blood by SP7 compared with plasma results by either aca or YSI.

Autoanalysis↗
PubMed1992

Prenatal weight gain advice: an examination of the recent prenatal weight gain recommendations of the Institute of Medicine.

The Institute of Medicine (IOM) recently published new guidelines for maternal weight gain during pregnancy. Using data collected at Moffitt Hospital, University of California at San Francisco, we examined the associations between maternal weight gain outside the recommendations of the IOM and three pregnancy outcomes (small for gestational age [SGA] infants, large for gestational age [LGA] infants, and cesarean delivery). These analyses were repeated using population-specific weight gain ranges derived from a subgroup of women in this cohort with healthy pregnancy outcomes. The purpose of the study was to compare the national guidelines of the IOM with hospital standards. Both the recommendations of the IOM and the hospital ranges were associated with fewer SGA infants, LGA infants, and cesarean deliveries. The overall associations were similar for the population-derived and national ranges. Although the IOM ranges should be examined in other populations and with other birth outcomes, our results validated their recommendations. Maternal weight gain within the IOM recommendations reduced the risk of the outcomes studied; furthermore, these ranges performed as well as those derived from the target population.

Birth Weight↗