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Biomedical subjects

R Firth

Publications and source records attributed to R Firth.

9 recordsLinked to original sources
PubMed1992

The timing of delivery in diabetic pregnancy: a 10-year review.

The approach of term in the pregnancy of a diabetic woman is a time of anxiety for patient and physician alike. The impact of a conservative approach to the timing of delivery is outlined in this review of the clinical course and outcome of 276 pregnancies of diabetic women, delivered at the National Maternity Hospital, Dublin between 1981 and 1990. The mean gestation at delivery was 39 weeks, 229 patients (83%) delivered at or beyond 38 weeks and 112 patients (41%) delivered at or beyond 40 weeks. The overall induction of labour rate was 27% and the elective Caesarean section rate was 19%. Sixty seven percent of patients achieved a normal delivery, the forceps rate was 5%, and 28% of patients were delivered by Caesarean section. There were 16 perinatal deaths in the series, with 7 due to lethal malformations. There were 5 deaths of normally formed infants occurring at or beyond 38 weeks' gestation. All of these 5 deaths had been preceded by clinically apparent polyhydramnios or macrosomia and recognized poor control. This study stresses the value of strict diabetic control in the management of diabetic pregnancy and highlights the significance of polyhydramnios and macrosomia as indicators of risk approaching term in diabetic pregnancy.

Adolescent↗
PubMed1987

Insulin action in non-insulin-dependent diabetes mellitus: the relationship between hepatic and extrahepatic insulin resistance and obesity.

To determine the contribution of obesity to the insulin resistance of non-insulin-dependent diabetes mellitus, insulin dose response curves for suppression of glucose production and stimulation of glucose utilization were generated in lean and obese diabetic patients and compared to those observed in weight-matched nondiabetic subjects. Glucose utilization during 0.4, 1.0, and 10.0 mU/kg x min insulin infusions (producing insulin concentrations ranging from approximately 50 to 2,000 microU/mL) was lower (p less than .02 to .001) in lean and obese diabetic patients compared to weight-matched nondiabetic subjects indicating insulin resistance. Glucose utilization was not correlated with obesity in the diabetic subjects. Suppression of glucose production was impaired (P less than .03 and .001) in both the lean and obese diabetic subjects at physiologic but not supraphysiologic insulin concentrations. We conclude that patients with NIDDM have both hepatic and extrahepatic insulin resistance, the severity of which appears to be independent of the degree of obesity.

Blood Glucose↗
PubMed1987

Effects of tolazamide and exogenous insulin on pattern of postprandial carbohydrate metabolism in patients with non-insulin-dependent diabetes mellitus. Results of randomized crossover trial.

To determine whether therapy with exogenous insulin or sulfonylureas results in a postprandial pattern of carbohydrate metabolism in patients with non-insulin-dependent diabetes mellitus (NIDDM) that resembles that in nondiabetic individuals, we employed a dual-isotope technique combined with forearm catheterization to examine meal disposition in NIDDM patients, before and after 3 mo of therapy with tolazamide and after 3 mo of therapy with exogenous insulin, with a randomized crossover design. Results were compared with those observed in nondiabetic subjects. Although both forms of therapy improved chronic glycemic control (glycosylated hemoglobin concentration went from 9.6 +/- 0.7 to 7.6 +/- 0.5 and 7.1 +/- 0.2%, respectively, P less than .01), exogenous insulin resulted in a lower postprandial glycemic response than tolazamide (P less than .001). Both agents comparably increased (P less than .01) fasting and integrated postprandial insulin concentrations. However, the initial rate of postprandial increase was greater with exogenous insulin (P less than .05). Tolazamide (P less than .05) but not exogenous insulin increased postprandial C-peptide concentrations. However, tolazamide did not improve the deficient early insulin release. Both agents (P less than .05) lowered postabsorptive hepatic glucose release (from 2.8 +/- 0.3 to 2.3 +/- 0.2 mg . kg-1 . min-1), but not to normal rates (1.8 +/- 0.1 mg . kg-1 . min-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1986

The role of autoregulation of the hepatic glucose production in man. Response to a physiologic decrement in plasma glucose.

In man, a decrease in plasma glucose concentration results in a compensatory increase in hepatic glucose release. Studies in vitro have suggested that a low glucose concentration per se may directly stimulate hepatic glucose release, an effect often referred to as autoregulation. Whether autoregulation occurs in man in response to a physiologic decrement in blood glucose is not known. Therefore, seven healthy, nonobese subjects were studied on two occasions to determine the role of autoregulation in mediating the increase in glucose production that accompanies a physiologic decrement in plasma glucose concentration. On both occasions, plasma glucose concentrations were clamped successively at 95, 65, and 95 mg/dl for 2 h each. Insulin (approximately 14 microU/ml) and glucagon (approximately 70 pg/ml) were maintained constant on both occasions by an infusion of somatostatin and insulin. Phentolamine and propranolol also were infused on one occasion to produce combined alpha- and beta-adrenergic blockade. In the absence of adrenergic blockade, glucose production increased by approximately 1.3 mg/kg X min when the plasma glucose concentration was decreased from 95 to 65 mg/dl and decreased by approximately 1.5 mg/kg X min when glucose was increased from 65 to 95 mg/dl. In the presence of adrenergic blockade, the increase and decrease in glucose production averaged 0 and 0.5 mg/kg X min, respectively, representing 70-100% inhibition. We conclude that, in the presence of low physiologic insulin concentrations, autoregulation is not a major contributor to the hepatic response to a physiologic decrement in plasma glucose concentration in man.

Adult↗
PubMed1969

Large-scale screening by the automated Wassermann reaction.

In view of the drawbacks in the use of the Kahn test for large-scale screening of blood donors, mainly those of human error through work overload and fatiguability, an attempt was made to adapt an existing automated complement-fixation technique for this purpose. This paper reports the successful results of that adaptation.

Automation↗