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Biomedical subjects

W M Crosby

Publications and source records attributed to W M Crosby.

At least 19 recordsLinked to original sources
PubMed1991

Studies in fetal malnutrition.

Fetal malnutrition, a worldwide problem, is accompanied by varying degrees of lifelong morbidity for the child. Only 25% of fetal malnutrition is accomplished by maternal risk factors known to cause intrauterine growth retardation (ie, chronic hypertension, advanced diabetes mellitus, or severe preeclampsia). If the malnourished fetus could be detected early in pregnancy, nutritional intervention might be successful in improving fetal growth rate and in avoiding the morbidity due to malnutrition. This communication reviews the almost 40 years of studies by Jack Metcoff, MD, and coworkers to unravel the causes of fetal malnutrition and their efforts to prevent it.

Female↗
PubMed1989

Twin pregnancy: an appraisal of management options.

For term twins, delivery in a referral center is probably not important to survival, but the method of delivery might be, depending upon the development of fetal distress and the immediate availability of cesarean section.

Delivery, Obstetric↗
PubMed1989

Smoking in pregnancy: relation of birth weight to maternal plasma carotene and cholesterol levels.

Not all mothers who smoke during pregnancy deliver small infants. Nutritional supplementation during pregnancy apparently protects the fetuses of some mothers. Our previous studies showed that plasma levels of carotene and cholesterol were correlated with birth weight. The present study examined the association between mid-pregnancy plasma levels of carotene and cholesterol and subsequent birth weight. In a prospective study of 388 women (47.8% smokers), levels of plasma nutrients and demographic and anthropometric measurements were obtained at 19 and 36 weeks' gestation and related to indices of infant size at birth. In non-smokers, the level of plasma cholesterol at mid-pregnancy correlated positively with birth weight. In contrast, in mothers who smoked more than ten cigarettes daily, the relationship of cholesterol to birth weight was dependent on the simultaneously observed level of plasma carotene. When plasma cholesterol and carotene concentrations were both low at mid-pregnancy, birth weight was low. On the other hand, when the carotene level was high and the cholesterol level low, birth weight was at least equivalent to that of non-smokers. The interactive effect of smoking, cholesterol, and carotene on birth weight was significant (P = .017) after adjusting for gestational age, sex, prenatal care, race, previous low birth weight infants, parity, weight at mid-pregnancy, and total weight gain during pregnancy. Among smokers, the smallest infants were born to mothers having the greatest decrease in plasma carotene between 19-36 weeks' gestation. Smokers whose plasma carotene remained constant or increased had larger infants; a similar association was not observed for cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Anthropometry↗
PubMed1986

Quantitative glomerular morphology of the normal and diabetic baboon kidney.

This is a study of quantitative glomerular morphology in 14 normal and 6 long-term diabetic female baboons between 3 and 25 years of age. In the normal female baboon, peripheral glomerular capillary basement membrane thickness increased until around 10 years of age, reached a plateau between 10 and 20 years of age, and possibly decreased at 25 years of age. Mean value for young (3 to 7 years of age) and older (10 to 25 years of age) controls were 266 nm and 329 nm respectively. Fractional volumes of mesangial matrix (8.9%) and mesangial cells (6.8%) were not affected by age. Glomerular basement membrane thickness and the volume of mesangial matrix increased progressively in female baboons with poorly controlled pancreatectomy-induced diabetes, while the volume of mesangial cells remained unchanged. After 106 to 145 months of diabetes, glomerular basement membrane thickness and the volume of mesangial matrix were 558 nm and 18.7% respectively. These values were significantly greater than those of the age-matched controlled (p = less than 0.05). By light and electron microscopy, the normal baboon glomerular morphology, morphometric measurements and changes with age were similar to those in man. The renal changes in diabetic baboons were also similar in morphology and rate of development to those of mild to moderate diffuse diabetic glomerulosclerosis in humans, indicating that the baboon is an ideal model for the long-term study of diabetic glomerulosclerosis. The presence of considerable interanimal variability in the degree of glomerulosclerosis attained after prolonged diabetes suggested that glomerulosclerosis progressed at different rates in these models. The reason for this was not apparent.

Aging↗
PubMed1985

Effect of food supplementation (WIC) during pregnancy on birth weight.

Of 824 women screened, 410 were enrolled at midpregnancy in a prospective, randomized, controlled nutrition intervention study. Of these, 226 were predicted as likely to have small or large babies, 184 to have average-sized babies. Two hundred thirty eight mothers received USDA Women, Infants and Children (WIC) Food Supplementation vouchers from midpregnancy, 172 did not. Leukocyte protein synthesis (as a cell model) was significantly higher (p = 0.009) by 36 weeks gestation in supplemented mothers. Mean birth weight of their babies was greater, 3254 vs 3163 g, (+91 g) p = 0.039, adjusted for sex, gestational age, prenatal visits, pregnancy interval, smoking, and previous low birth weight infants. Controlling for entry weight obviated the significance of the difference, except for WIC supplemented smokers (greater than 10 cigarettes/day) whose babies were significantly heavier by +168 g (p = 0.017) than those of unsupplemented smokers. WIC partially protects fetal growth in smokers.

Birth Weight↗
PubMed1978

Response of immature baboon fetal lung to intra-amniotic betamethasone.

Intra-amniotic betamethasone (6 mg.) given to six immature fetal baboons, at four and again at three days prior to delivery by cesarean section, between 147 and 158 days' gestation (term = 180 days), significantly increased the amniotic fluid lecithin/sphingomyelin (L/S) ratio. At delivery, treated animal lungs were more mature in that they had a significantly increased deflation stability and significantly decreased minimum surface tension in minced lung when compared to five control animals. Changes in maximum air distensibility lagged behind changes in deflation stability. The major molecular species of pulmonary phosphatidylcholine were analyzed by gas liquid chromatography as the diacylglycerol derivatives. The proportions of 14:0/16:0, 16:0/16:0, and 16:0/18:0, were significantly increased over control proportions while unsaturated species tended to decrease in animals exposed to intra-amniotic betamethasone. The immature fetal baboon pulmonary system responded to intra-amniotic betamethasone with a synchronous increase in the L/S ratio, improved pulmonary stability, and a more mature pulmonary lecithin composition, but did not demonstrate a synchronous increase in tissue distensibility.

Amnion↗
PubMed1978

Relationship of maternal amino acid profiles at 25 weeks of gestation to fetal growth.

In a study of the relationship of maternal nutrition to fetal development, the free amino acid concentration was determined in the plasma of 43 subjects sampled between the 20th to 30th (25 +/- 3.7) week of pregnancy. Significant positive correlations were found between mothers' 25-week plasma levels of aspartic acid, serine, alanine, tyrosine, ornithine, and arginine, and babies' size at birth. The concentration of total free amino acids in plasma from mothers of fetally malnourished infants, was significantly lower than that from mothers having normal babies. The branched chain amino acids isoleucine and valine were at normal levels, suggesting a sparing effect for these amino acids.

Amino Acids↗
PubMed1977

Fetal malnutrition: an appraisal of correlated factors.

Fetal malnutrition has emerged as a significant health problem over the past decade. Present evidence suggests that maternal environment plays the major etiologic role in fetal malnutrition. The association of fetal malnutrition in mothers with chronic hypertension is well known, but fetal malnutrition is associated with maternal hypertension in less than 25 per cent of cases. Among a group of 182 pregnant women studied at midpregnancy for blood levels of vitamins, trace metals, proteins, amino acids, and parameters of maternal leukocyte energy metabolism, it was found that the concentration of 10 amino acids, alpha-1-globulin, zinc, and total carotenes had a statistically significant relationship to fetal growth. Similarly significant correlations were found for maternal leukocyte adenosine disphosphate, phosphofructokinase activity, ribonucleic acid (RNA) synthesis, and cell size. Maternal cigarette smoking was correlated with reduced fetal growth. Analysis showed that there was a significant reduction in leukocyte RNA synthesis and phosphokinase activity and in the plasma levels of 14 amino acids, and carotene in smoking mothers. This information lends support to the hypothesis that factors which affect the growth of fetal cells also will affect maternal leukocytes in a definable way.

Adolescent↗
PubMed1977

Eisenmenger's syndrome in pregnancy: does heparin prophylaxis improve the maternal mortality rate?

Seven consecutive patients with Eisenmenber's syndrome, cared for by the obstetric team in conjunction with the cardiology service, were reviewed to assess the possible role of prophylactic heparin therapy and intensive care on the outcome of these patients. In each patient, the diagnosis of Eisenmenger's syndrome was established by the demonstration of equal pulmonary arterial and aortic pressures with a predominantly right-to-left shunt at cardiac catheterization. Five of the seven patients died as follows: Three patients died between the fifth and eighth post-partum days, one patient died during the twenty-sixth week of pregnancy, and one patient died on the fifth postoperative day following tubal ligation. All of these five patients received prophylactic heparin therapy. In three patients, heparin therapy was complicated by excessive bleeding during the postoperative or postpartum period. Autopsy examination in two patients revealed no evidence of thrombosis in the main pulmonary arteries and no pulmonary infarction, contrary to the antemortem clinical suspicion. The two survivors did not receive prophylactic heparin. They comprised one patient who had normal delivery and one patient who underwent tubal ligation and induction of abortion. We conclude that the prohibitive mortality rate of Eisenmenger's syndrome during pregnancy, puerpurium, or surgical procedures probably cannot be modified with prophylactic heparin therapy. Anticoagulant treatment does not prevent deterioration of patients and probably compounds the problem by causing significant bleeding.

Adolescent↗
PubMed1977

Antenatal glucocorticoid therapy for the prevention of respiratory distress syndrome in the premature infant.

A double-blind study was designed to investigate the effects of antenatal glucocorticoids on the incidence of respiratory distress syndrome (RDS) in 128 premature human infants. There was a significant reduction (P less than 0.05) in the incidence of RDS in the betamethasone-treated infants to 8.7% compared to an incidence of 22.6% in the saline-treated controls and 25.0% in infants whose mothers received methylprednisolone. The effectiveness of betamethasone in reducing RDS was limited to premature infants delivered to mothers with intact fetal membranes and with an initial L/S ratio less than 2.0. The time between administration of the glucocorticoid and delivery did not significantly affect the incidence of RDS in this study. The failure of methylprednisolone to reduce the development of RDS in premature infants suggests its potential use in maternal therapy during pregnancy with minimal effects on fetal maturation.

Amniotic Fluid↗