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Biomedical subjects

B F Mitchell

Publications and source records attributed to B F Mitchell.

60 records · Page 4Linked to original sources
PubMedDate not supplied

Relationship between plasma glucose levels in glucose-intolerant women and newborn macrosomia.

The purpose of this study was to examine the relationship between newborn macrosomia and plasma glucose profile in both a "glucose challenge test (GCT)-positive oral glucose tolerance test (OGTT)-negative" group (n = 113) and a gestational diabetes mellitus (GDM) group (n = 50). We examined 1) plasma glucose concentrations following a positive screen 50-g GCT (n = 163), 2) glucose concentrations following a 100-g OGTT (n = 163), and 3) the average fasting (AF) and 2-hour postprandial (APP) plasma glucose concentrations in the treated GDM group (n = 46). It was a case-control study with macrosomia vs. non-macrosomia in the ratio of 1:4. Macrosomia was analyzed by both birthweight > 4,000 g and gender-specific birthweight > 90th percentile for gestational age criteria. The GCT and the OGTT were performed between 26 and 30 weeks of pregnancy. The results demonstrated no significant impact of plasma glucose values from GCT, OGTT, AF, or APP on macrosomia in both "GCT-positive OGTT-negative" and GDM (treated) groups. Further, the screening and diagnostic plasma glucose concentrations were not related to macrosomia in both "GCT-positive OGTT-negative" and GDM groups. We found a difference of 0.6 mmol/liter in the maternal AF and APP glucose concentrations between mothers of macrosomic versus non-macrosomic newborns in the treated (diet or diet+insulin) GDM group. The clinical relevance of this difference remains to be explored. Our study provides a different methodological and analytic perspective in examining macrosomia versus non-macrosomia in the "GCT-positive OGTT-negative" and the GDM groups using univariate and multivariate analyses.

Birth Weight↗
PubMedDate not supplied

Relative importance of maternal constitutional factors and glucose intolerance of pregnancy in the development of newborn macrosomia.

The purpose of this case-control study was to determine the relative importance of various predictors of newborn macrosomia, with particular reference to maternal constitutional factors and glucose intolerance of pregnancy. Macrosomia was defined by both absolute birthweight > or = 4,000 g and birthweight > or = 90th centile for gestational age. One thousand mother/newborn pairs [209 macrosomic (cases) and 791 non-macrosomic newborns (controls)] were recruited. Mothers with pre-gestational diabetes mellitus were excluded. Data on pregnancy and pregnancy variables were collected by review of prenatal, labour, and delivery and newborn assessment records and interview with the mother. Predictors that entered the stepwise multiple regression model in order of significance were: previous history of macrosomia, increasing maternal weight, nonsmoking status, multiparity, male newborn gender, gestational age of 40-42 weeks, North American Aboriginal ethnicity, maternal birthweight > 4,000 g, maternal height and maternal age < 17 years. Glucose screen positive/100-g oral glucose tolerance test (GTT) negative status was a significant predictor for macrosomia as defined by birthweight greater than the 90th percentile for gestational age, but not for absolute birthweight over 4,000 g. It was the least significant of all the factors examined. Treated gestational diabetes was not a significant predictor. By multivariate analysis, maternal constitutional factors are more powerful predictors of newborn macrosomia than maternal mild glucose intolerance. Treatment of mothers with GDM may be masking the effect of more pronounced carbohydrate intolerance.

Adolescent↗
PubMedDate not supplied

Oxytocin and its receptor in the process of parturition.

OBJECTIVE: To review the potential roles of oxytocin (OT) and its receptor (OTR) in the regulation of parturition. METHODS: We reviewed the literature to describe the molecular aspects of the mechanisms of action and the regulation of OT and its receptor, particularly in relation to changes that occur at parturition. RESULTS: The literature provides strong support for a role for the OT/OTR system in the regulation of human parturition. Paracrine rather than endocrine mechanisms might be more important, and the regulation of the receptor might be more important than the ligand. The system is regulated by a wide variety of chemical and physical factors, including sex steroids, orphan receptors, uterine stretch, and many others. There also might be important interactions with the immune system. CONCLUSION: The OT/OTR system provides a potentially important therapeutic target for regulating the timing of human birth.

Animals↗