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Biomedical subjects

A J Scheen

Publications and source records attributed to A J Scheen.

477 records · Page 27Linked to original sources
PubMedDate not supplied

Measurement of insulin sensitivity by the minimal model method using a simplified intravenous glucose tolerance test: validity and reproducibility.

This study aimed at testing whether 12 rather than 26 plasma glucose and insulin determinations can be used to calculate the indices of insulin sensitivity and of glucose effectiveness using Bergman's minimal model during a simple intravenous glucose tolerance test performed without tolbutamide injection. Two intravenous glucose tolerance tests (separated by 1 week) were performed in 7 lean normal subjects and a single test was performed in 9 severely obese non-diabetic subjects. Intra-subject reproducibility of insulin sensitivity was not significantly different when 26 or 12 time-points were analyzed (CV = 16.8 +/- 3.4 versus 18.9 +/- 3.8% respectively). Compared with the insulin sensitivity of the lean subjects, that of obese subjects was significantly (P < 0.001) and similarly reduced when using 12 (2.14 +/- 0.34 versus 7.97 +/- 1.29 10(-4)min-1/mU.1-1) rather than 26 determinations (2.13 +/- 0.42 versus 6.95 +/- 1.12 10(-4) min-1/mU.1-1) respectively. Glucose effectiveness was less reproducible than insulin sensitivity and was slightly diminished by the reduction of blood samples (relative error: -9.7 +/- 4.4%; P < 0.05). Finally, glucose effectiveness tended to be slightly lower in the morbidly obese subjects than in the lean controls with both modes of calculation. In conclusion, in non-diabetic subjects, the insulin sensitivity index can be accurately measured during a simple intravenous glucose tolerance test, without tolbutamide injection and with only 12 blood samples. The possibility of performing a simplified test should contribute to increase the use of the minimal model method for estimating insulin sensitivity in clinical practice.

Adult↗
PubMedDate not supplied

Pharmacological treatment of the obese diabetic patient.

Obesity is a well-known risk factor for non-insulin-dependent (or Type 2) diabetes mellitus. Consequently, reduction of weight excess comes to the front line in the prevention and management of NIDDM. It is only when diet and physical exercise fail that drug treatment should be considered. Pharmacological treatment of obesity should favour drugs which not only promote weight loss, by reducing caloric intake and/or increasing thermogenesis and energy expenditure, but also, and especially, improve insulin sensitivity. Serotoninergic anorectic compounds (dexfenfluramine, fluoxetine) appear to possess, to some extent, all these properties. Metformin significantly reduces insulin resistance and improves glycaemic control without inducing weight gain, and even favouring some weight loss. This biguanide is now considered as the first line drug for the obese diabetic patient. Alpha-glucosidase inhibitors may help to reduce post-prandial glucose excursions but do not promote weight loss per se. Sulfonylureas can be prescribed to an obese patient when hyperglycaemia persists despite diet and the above-mentioned oral agents, but their use should be associated with reinforcement of dietary advices in order to prevent further weight increase; it is also the case for insulin therapy. Finally, drugs specifically stimulating thermogenesis and energy expenditure, new agents sensitizing tissues to the action of insulin and various compounds interfering with lipid metabolism are currently under extensive investigation with promising preliminary results in the obese diabetic patient. In conclusion, obesity remains a major problem in the management of Type 2 diabetes mellitus and this justifies the search for new, safe and effective, pharmacological approaches.

Diabetes Mellitus↗
PubMedDate not supplied

[Magnesium and glucose metabolism].

The interrelationships between magnesium and carbohydrate metabolism have regained considerable interest over the last few years. Insulin secretion requires magnesium: magnesium deficiency results in impaired insulin secretion while magnesium replacement restores insulin secretion. Furthermore, experimental magnesium deficiency reduces the tissues sensitivity to insulin. Subclinical magnesium deficiency is common in diabetes. It results from both insufficient magnesium intakes and increase magnesium losses, particularly in the urine. In type 2, or non-insulin-dependent, diabetes mellitus, magnesium deficiency seems to be associated with insulin resistance. Furthermore, it may participate in the pathogenesis of diabetes complications and may contribute to the increased risk of sudden death associated with diabetes. Some studies suggest that magnesium deficiency may play a role in spontaneous abortion of diabetic women, in fetal malformations and in the pathogenesis of neonatal hypocalcemia of the infants of diabetic mothers. Administration of magnesium salts to patients with type 2 diabetes tend to reduce insulin resistance. Long-term studies are needed before recommending systematic magnesium supplementation to type 2 diabetic patients with subclinical magnesium deficiency.

Animals↗
PubMedDate not supplied

[Hyperlipemias and hypolipemic agents].

Hyperlipidaemia, as a primary atherogenic risk factor, represents a major problem of public health. This review first reminds the main steps of lipoprotein metabolism, the classification of the most frequent hyperlipidaemias, the objectives of the treatment and the required initial evaluation allowing to decide how to manage the patient. Thereafter, it describes all the available treatments, more particularly the characteristics of the various lipid lowering drugs. Finally, it proposes a step by step strategy for the treatment of the main hyperlipidaemias and summarizes the managements of some particular cases.

Humans↗
PubMedDate not supplied

[Rapid determination by immunoassay of glycosylated hemoglobin in capillary blood compared to an affinity method for boronate and ion capturing on venous blood].

Measurement of glycosylated haemoglobin has become an essential tool in the management of diabetic patients. A recently developed device allows the rapid immuno-assay of HbA1c in 1 microliter capillary blood obtained by a finger prick. In 100 ambulatory diabetic patients, we compared the results obtained with this method to those obtained in venous blood using a standard affinity chromatography laboratory method. Although both methods correlated (r = 0.88, p < 0.001), the mean +/- SD levels respectively obtained differed slightly (7.6 +/- 1.5 vs 79 +/- 1.4% p < 0.001). The 95% confidence interval of the difference was [-0.41. -0.14]. Considering a cut-off HbA1c value of 8%, as indicative of the need for treatment adjustment, 33 patients with the capillary blood immuno-assay method and 42 with the venous-blood affinity chromatography method were above that limit (Mc Nemar test, p < 0.05). In conclusion, the rapid assay of HbA1c in capillary blood can be useful for the management of some diabetic patients but the results are not readily exchangeable with those obtained from other standardized laboratory methods. Consequently, specific ranges and clinical decision limits must be determined.

Adolescent↗