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Biomedical subjects

P Felig

Publications and source records attributed to P Felig.

At least 73 records · Page 4Linked to original sources
PubMed1980

Nitrogen and sodium balance and sympathetic-nervous-system activity in obese subjects treated with a low-calorie protein or mixed diet.

Seven obese subjects were placed on a 400-kcal protein diet and on an isocaloric mixed diet (50 per cent protein and 50 per cent carbohydrate), three to 5 1/2 weeks for each diet. Despite twofold to fivefold increases in ketone levels in the blood and urine with the protein diet, net nitrogen balance was no different from that with the mixed diet (-2.1 +/- 0.9 vs. -2.6 +/- 0.4 g per day; mean +/- S.E.M.). However, net sodium loss with the protein diet (-382 +/- 117 mmol) was significantly greater than with the mixed diet (-25 +/- 105 mmol; P less than 0.02). Furthermore, maximal orthostatic decreases in systolic blood pressure with the protein diet (-28 +/- 3 mm Hg) were greater than with the mixed diet (-18 +/- 3 mm Hg; P less than 0.02) and were accompanied by symptoms of orthostatic hypotension in all patients. The protein diet (but not the mixed diet) also resulted in a 40 per cent decline in basal plasma levels of norepinephrine (P less than 0.01) and a failure of plasma norepinephrine to rise after two minutes of standing. We conclude that as compared with mixed diets, hypocaloric protein diets offer no advantage with respect to nitrogen metabolism but result in greater sodium depletion, a decrease in sympathetic-nervous-system activity, and the development of orthostatic hypotension.

Adult↗
PubMed1980

Outpatient treatment of juvenile-onset diabetes with a preprogrammed portable subcutaneous insulin infusion system.

Seven patients with juvenile-onset, insulin-dependent diabetes (aged 13 to 32 years) were continuously treated for 12 to 32 weeks while out of the hospital in their usual environment with a portable, battery-powered infusion pump which delivers insulin subcutaneously in basal (between-meal) doses with pulse dose increments before meals. Mean blood glucose levels (237 +/- 28 mg/dl during conventional insulin therapy) fell to 105 +/- 5 mg/dl after four weeks of pump treatment (p less than 0.01) and were maintained at 80 to 104 mg/dl as pump treatment was continued beyond eight weeks. Glycosylated hemoglobin levels (16.0 +/- 1.5 per cent before pump therapy) also fell within two weeks (p less than 0.01) reaching normal values (9.9 +/- 0.3) after eight weeks of pump therapy. Mean plasma cholesterol and triglyceride levels were elevated during conventional therapy and fell to normal after pump treatment. After the first month of pump treatment, only minor adjustments in insulin dose (less than 5 per cent of total daily dose) were made. No episode of mechanical pump failure occurred during the 1,110 patient-days of treatment. Overinsulinization and underinsulinization due to human error were relatively rare (four and six episodes, respectively) and failed to result in symptoms of hypo- or hyperglycemia. All patients performed their usual home, work or school activities during pump treatment. We conclude that normalization or near normalization of blood glucose levels can be achieved with a portable subcutaneous insulin infusion system when continuously used to treat patients with juvenile-onset, insulin-dependent diabetes outside the hospital for three to eight months.

Adolescent↗
PubMed1980

Substrate, hormone, and temperature responses in males and females to a common breakfast.

To evaluate the response to a mixed meal we studied oral temperature, metabolite, and hormonal responses to a common American breakfast containing 11 kcal/kg body weight (carbohydrate 43%, fat 42%, and protein 15%) in 12 normal volunteers (6 males and 6 females). There was a significant rise in oral temperature during the postcibal period. This change in oral temperature did not depend upon food consumption in males but was meal-dependent in females. Food ingestion caused increases in the peripheral circulating concentrations of glucose, lactate, pyruvate, and amino acids and reciprocal decreases in the concentrations of free fatty acids, glycerol, and urea nitrogen. Acetoacetate and beta-hydroxybutyrate decreased during the postcibal period but the changes were not statistically significant. Although peripheral venous serum insulin and plasma glucagon concentrations were indistinguishable between the sexes, males had higher concentrations of plasma triglycerides, plasma amino acids, and serum urea nitrogen. Peripheral venous plasma somatostatin and secretin remained unchanged, but pancreatic polypeptide hormone showed a large biphasic response to the meal. After breakfast the blood glucose concentration tended to be greater in males than in females and this difference was significant at 60 and 120 min postcibal. Furthermore, every female had a 120 min postcibal glucose concentration that was lower than her basal fasting glucose concentration. This suggests that postcibal glucose concentrations should be related to gender in making the diagnosis of carbohydrate intolerance or reactive hypoglycemia.

Adult↗
PubMed1980

Effects of acute exercise on insulin binding to monocytes in obesity.

The effect of 3 hr of cycle erogmeter exercise on 125I-insulin binding to monocytes was studied in obese and 10 nonobese control subjects. In the basal state before exercise, total specific 125I-insulin binding to monocytes in obese subjects (4.8% +/- 0.3%) was 25% lower than in control subjects (6.6% +/- 0.4%, p less than 0.01). During exercise, insulin binding increased in both groups (p less than 0.05), but the rise in obese subjects was minimal (13% +/- 1%) and was 60%--70% lower than in controls (36% +/- 3%, p less than 0.01). The data indicate that the increment in insulin binding to monocytes induced by acute exercise is diminished in obesity.

Adult↗
PubMed1980

Amino acid metabolism in uremia: insights gained from normal and diabetic man.

The physiology of the interorgan exchange of amino acids in healthy subjects and in insulin-dependent diabetics is reviewed and compared with changes observed in patients with chronic renal failure. In contrast to the diabetic, who has elevated fasting branched-chain amino acid levels and diminished muscle uptake of branched-chain amino acid following protein feeding, fasting levels of leucine, isoleucine, and valine are decreased in uremia. Furthermore, the decline in branched-chain amino acids following insulin in normal and intracellular levels of leucine and isoleucine have been reported to be normal. With respect to alanine metabolism, the diabetic state is characterized by diminished fasting alanine levels which are due to a 2-fold increase in splanchnic alanine extraction. Accordingly, gluconeogenesis can potentially account for over 30 to 40% of hepatic glucose production compared to 15 to 20% in normal man. In uremia, fasting alanine levels are normal and hepatic alanine uptake is not increased. Similarly, basal hepatic glucose production, as well as suppression of glucose production following insulin, are normal in uremic subjects. Thus, although uremia is characterized by abnormalities in the metabolism of many individual amino acids, it does not appear to share the same disturbances in alanine and branched-chain amino acid metabolism that are associated with insulin deficiency.

Amino Acids↗
PubMed1980

Effects of acute exercise and training on insulin binding to monocytes and insulin sensitivity in vivo.

Insulin binding to monocytes was studied in well-trained long distance runners and in sedentary control subjects in the resting state and after 3 h cycle ergometer exercise at 40% of maximal aerobic power. In addition, in previously untrained subjects we examined the effect of 6 weeks of training on insulin binding to monocytes and insulin sensitivity in vivo. In the athletes at rest, insulin binding to monocytes was 69% higher than in controls (p less than 0.01), and correlated with maximal aerobic power (r = 9.63, p less than 0.05). The rise in insulin binding in the athletes was due to an increase in binding capacity rather than a change in binding affinity. During exercise, insulin binding fell in athletes by 31% (p less than 0.025) in contrast to a 35% rise observed in control subjects (p less than 0.01). As compared to controls, the athletes had a lower respiratory exchange ratio and a smaller decline in plasma glucose during exercise. In previously untrained subjects, physical training resulted in a 35% rise in insulin binding to monocytes (p less than 0.02). The rise in binding was due mainly to an increase in binding capacity. Insulin mediated glucose uptake (as measured by insulin clamp technique) also rose by 30% after physical training (p less than 0.01). The rise in insulin sensitivity was proportional to the improvement in physical fitness (r = 0.81, p less than 0.05). These findings indicate that (a) elevated insulin binding may contribute to the enhanced insulin sensitivity observed after physical training, (b) a fall in insulin binding in athletes during acute exercise may contribute to a greater shift from carbohydrate to fat utilization during exercise in athletes as compared to sedentary controls. These data suggest that physical training may provide a means of reversing or ameliorating abnormalities in insulin binding and sensitivity in insulin resistant states, such as obesity or maturity onset diabetes.

Adult↗
PubMed1980

Alterations in insulin absorption and in blood glucose control associated with varying insulin injection sites in diabetic patients.

In seven insulin-dependent diabetic subjects the disappearance rate of 125I-labelled short-acting insulin from injection sites in the abdominal wall was 86% greater than from the leg (P less than 0.005) and 30% greater than from the arm (P less than 0.05). Absorption from the arm was 40% greater than from the leg (P less than 0.05). The postprandial rise in plasma glucose concentration varied inversely with the rate of insulin absorption and was 30 to 50 mg/dL less after abdominal than after leg injection; the glycemic response after arm injection was intermediate between that after leg and abdominal injection. These results indicate that changing the insulin injection site from the leg to the abdomen or arm accelerates the absorption of insulin and diminishes the postprandial rise in plasma glucose. Varying insulin injection sites within the same anatomic region rather than between different regions may diminish daily variations in insulin absorption and in metabolic control in insulin-dependent diabetic subjects.

Abdominal Muscles↗