Hepatic glucose metabolism after fructose ingestion in NIDDM and obses non diabetic subjects.
PAQUOT, Nicolas ; ; et al
in Diabetes (1995), 44(suppl 1), 254Detailed reference viewed: 5 (0 ULg)
Métabolisme hépatique du glucose après ingestion de fructose chez des sujets obèses non diabétiques et diabétiques non insulinodépendants
PAQUOT, Nicolas ; ; et al
in Diabète & Métabolisme (1995), 21(suppl),Detailed reference viewed: 28 (2 ULg)
Glucose metabolism in obese subjects: lessons from OGTT, IVGTT and clamp studies.
Scheen, André ; Paquot, Nicolas ; Letiexhe, Michel et al
in International Journal of Obesity & Related Metabolic Disorders (1995), 19 Suppl 3
Impaired glucose tolerance and overt diabetes are more frequent in presence than in absence of obesity. In obese subjects, glucose tolerance can be maintained within the normal range by compensating for ... [more ▼]
Impaired glucose tolerance and overt diabetes are more frequent in presence than in absence of obesity. In obese subjects, glucose tolerance can be maintained within the normal range by compensating for insulin resistance by peripheral hyperinsulinism, the latter resulting from both increased insulin secretion and reduced insulin clearance. Impaired glucose tolerance is observed when insulin resistance is associated to impaired first-phase insulin response, which results in a significant increase in plasma glucose levels and a late insulin hyperresponsiveness. Both hyperinsulinaemia and hyperglycaemia are then able to overcome peripheral insulin resistance and impaired glucose disposal. When a more marked defect in insulin secretion is present, hyperglycaemia progresses, probably due to an additional participation of impaired suppression of hepatic glucose output. Overt diabetes then occurs with persistent post-absorptive hyperglycaemia. All these abnormalities can be reversed after a marked weight loss and recovery of ideal body weight, arguing for acquired rather than inherited metabolic defects in presence of morbid obesity. If a sufficient weight reduction can not be obtained, pharmacological approaches may be considered to improve insulin resistance of obese subjects, especially those with impaired glucose tolerance or overt diabetes. [less ▲]Detailed reference viewed: 42 (2 ULg)
24-hour glucose profiles during continuous or oscillatory insulin infusion. Demonstration of the functional significance of ultradian insulin oscillations.
; Scheen, André ; et al
in Journal of Clinical Investigation (1995), 95(4), 1464-71
Under basal and stimulated conditions, normal insulin secretion oscillates with periods in the ultradian 100-150-min range. To test the hypothesis that oscillatory insulin delivery is more efficient in ... [more ▼]
Under basal and stimulated conditions, normal insulin secretion oscillates with periods in the ultradian 100-150-min range. To test the hypothesis that oscillatory insulin delivery is more efficient in reducing blood glucose levels than continuous administration, nine normal young men were each studied on two occasions during a 28-h period including a period of polygraphically recorded sleep. Endogenous insulin secretion was suppressed by somatostatin, a constant intravenous glucose infusion was administered, and exogenous insulin was infused either at a constant rate or in a sinusoidal pattern with a period of 120 min. The mean glucose level over the 28-h period was 0.72 +/- 0.31 mmol/liter lower when insulin was infused in an oscillatory pattern than when the rate of infusion was constant (P < 0.05). The greater hypoglycemic effect of oscillatory versus constant infusion was particularly marked during the daytime, with the difference averaging 1.04 +/- 0.38 mmol/liter (P < 0.03). Serum insulin levels tended to be lower during oscillatory than constant infusion, although the same amount of exogenous insulin was administered under both conditions. Ultradian insulin oscillations appear to promote more efficient glucose utilization. [less ▲]Detailed reference viewed: 20 (1 ULg)
Glucose handling, diabetes and ageing.
; Scheen, André ; Lefebvre, Pierre
in Hormone Research (1995), 43(1-3), 52-7
The relationship between ageing and glucose homeostasis is still an open debate. In fact, the mechanisms by which glucose metabolism is progressively impaired with increasing age are not completely ... [more ▼]
The relationship between ageing and glucose homeostasis is still an open debate. In fact, the mechanisms by which glucose metabolism is progressively impaired with increasing age are not completely understood. In the present report we have reviewed the possible mechanisms (impaired insulin secretion and action, role of the environmental factors) which may lead to the impairment in glucose handling associated with ageing. We also point out that not all aged subjects are glucose intolerant; in fact, it has been suggested that only those aged subjects who present more than one pathological finding do in fact develop impaired glucose handling. [less ▲]Detailed reference viewed: 16 (1 ULg)
Le cas clinique du mois. Troubles electrolytiques severes dans l'anorexie mentale.
in Revue Médicale de Liège (1995), 50(1), 16-7Detailed reference viewed: 55 (1 ULg)
Amylin/islet amyloid polypeptide: biochemistry, physiology, patho-physiology.
; Scheen, André ; Lefebvre, Pierre
in Diabète & Métabolisme (1995), 21(1), 3-25
Amylin is a 37 amino-acid peptide mainly produced by the islet beta-cell. Aggregation of amylin is partly responsible for amyloid formation. Amyloid deposits occur both extracellularly and intracellularly ... [more ▼]
Amylin is a 37 amino-acid peptide mainly produced by the islet beta-cell. Aggregation of amylin is partly responsible for amyloid formation. Amyloid deposits occur both extracellularly and intracellularly and may contribute to beta-cell degeneration. Amylin is packed in beta-cell granules and cosecreted with insulin in response to the same stimuli but, unlike other beta-cell products, it is produced from specific a gene on chromosome 12. Basal, plasma amylin concentrations are around 5 pM, and increase fourfold after meals or glucose. Higher levels are found in cases of insulin resistance, obesity, gestational diabetes and in some patients with NIDDM. Low or absent levels are found in insulin-dependent diabetic patients. There are similarities between amylin and non beta-cell peptides such as calcitonin gene related peptides (CGRP). They may bind to the same receptor, determine similar post-receptor phenomena and qualitatively similar actions but with different degree of potency. The actions of amylin are multiple and mostly exerted in the regulation of fuel metabolism. In muscle, amylin opposes glycogen synthesis, activates glycogenolysis and glycolysis (increasing lactate production). Consequently, amylin increases lactate output by muscle and increases the plasma lactate concentration. In fasting conditions, this lactate may serve as a gluconeogenic substrate for the liver, contributing to replenish depleted glycogen stores and to increase glucose production. In non-fasting conditions, lactate can be transformed by liver in triglycerides. It is not clear at present whether amylin actions on the liver are direct or mediated by changes in circulating metabolites. A probably indirect effect of amylin in muscle is to decrease insulin- (or glucose)-induced glucose uptake, which may contribute to insulin resistance. Other actions include inhibition of glucose-stimulated insulin secretion and, in general, actions mimicking CGRP effects. Some of these actions are seen at supraphysiological concentrations. The physiopathological consequences of amylin deficiency, or excess are under active by investigated. [less ▲]Detailed reference viewed: 40 (1 ULg)
Retinopathy, but not neuropathy, is influenced by the level of residual endogenous insulin secretion in type 2 diabetes.
Bozet, Marie-Claire ; Scheen, André ; Gerard, Pascale et al
in Diabète & Métabolisme (1995), 21(5), 353-9
The files of 132 patients with Type 2 diabetes were retrospectively studied to characterize the influence of metabolic control and residual insulin secretion on neuropathy and retinopathy, the two most ... [more ▼]
The files of 132 patients with Type 2 diabetes were retrospectively studied to characterize the influence of metabolic control and residual insulin secretion on neuropathy and retinopathy, the two most frequent degenerative diabetic complications. Patients were classified according to their metabolic control (mean HbA1C either < or > or = 8%; reference values: 3-6%) and residual endogenous insulin secretion (fasting plasma C-peptide levels either < or > or = 0.600 nmol/l). Neuropathy was more frequent in patients with poor metabolic control (32/64 = 50%) than in those adequately controlled (17/68 = 25%; p < 0.005). In both subgroups, the level of endogenous insulin secretion did not influence the prevalence of neuropathy. Retinopathy was less effected than neuropathy by the degree of metabolic control (37.5% in the subgroup with HbA1C > or = 8% v.s. 25% in the subgroup with HbA1C < 8%; p < 0.10), but was influenced by residual insulin secretion. Indeed, in patients with inadequate metabolic control, the prevalence of retinopathy was significantly increased in those with higher endogenous insulin secretion (51.4 versus 20.6%, p < 0.02) and thus probably higher insulin resistance. Furthermore, higher systolic arterial blood pressure was observed in the subgroups with a higher prevalence of retinopathy. Such conclusions were confirmed using multivariate analysis. Thus, in Type 2 diabetes, neuropathy is essentially affected by the degree of metabolic control, whereas retinopathy is also influenced by the level of residual endogenous insulin secretion and the presence of systolic hypertension. [less ▲]Detailed reference viewed: 9 (0 ULg)
Antihyperglycaemic agents. Drug interactions of clinical importance.
Scheen, André ; Lefebvre, Pierre
in Drug Safety : An International Journal of Medical Toxicology & Drug Experience (1995), 12(1), 32-45
Non-insulin-dependent (type 2) diabetes mellitus (NIDDM) affects middle-aged or elderly people who frequently have several other concomitant diseases, especially obesity, hypertension, dyslipidaemias ... [more ▼]
Non-insulin-dependent (type 2) diabetes mellitus (NIDDM) affects middle-aged or elderly people who frequently have several other concomitant diseases, especially obesity, hypertension, dyslipidaemias, coronary insufficiency, heart failure and arthropathies. Thus, polymedication is the rule in this population, and the risk of drug interactions is important, particularly in elderly patients. The present review is restricted to the interactions of other drugs with antihyperglycaemic compounds, and will not consider the mirror image, i.e. the interactions of antihyperglycaemic agents with other drugs. Oral antihyperglycaemic agents include sulphonylureas, biguanides--essentially metformin since the withdrawn of phenformin and buformin--and alpha-glucosidase inhibitors, acarbose being the only representative on the market. These drugs can be used alone or in combination to obtain better metabolic control, sometimes with insulin. Drug interactions with antihyperglycaemic agents can be divided into pharmacokinetic and pharmacodynamic interactions. Most pharmacokinetic studies concern sulphonylureas, whose action may be enhanced by numerous other drugs, thus increasing the risk of hypoglycaemia. Such an effect may result essentially from protein binding displacement, inhibition of hepatic metabolism and reduction of renal clearance. Reduction of the hypoglycaemic activity of sulphonylureas due to pharmacokinetic interactions with other drugs appears to be much less frequent. Drug interactions leading to an increase in plasma metformin concentrations, mainly by reducing the renal excretion or the hepatic metabolism of the biguanide, should be avoided to limit the risk of hyperlactaemia. Owing to its mode of action, pharmacokinetic interferences with acarbose are limited to the gastrointestinal tract, but have not been extensively studied yet. Pharmacodynamic interactions are quite numerous and may result in a potentiation of the hypoglycaemic action or, conversely, in a deterioration of blood glucose control. Such interactions may be observed whatever the type of antidiabetic treatment. They result from the intrinsic properties of the coprescribed drug on insulin secretion and action, or on a key step of carbohydrate metabolism. Finally, a combination of 2 to 3 antihyperglycaemic agents is common for treating patients with NIDDM to benefit from the synergistic effect of compounds acting on different sites of carbohydrate metabolism. Possible pharmacokinetic interactions between alpha-glucosidase inhibitors and classical antidiabetic oral agents should be better studied in the diabetic population. [less ▲]Detailed reference viewed: 33 (0 ULg)
Postgastroplasty recovery of ideal body weight normalizes glucose and insulin metabolism in obese women.
Letiexhe, Michel ; Scheen, André ; Gerard, Pascale et al
in Journal of Clinical Endocrinology and Metabolism (1995), 80(2), 364-9
To study the metabolic effects of normalizing body weight, a frequently sampled iv glucose tolerance test (0.3 g/kg) was performed before [body mass index (BMI), 37.7 +/- 0.5 kg/m2] and 14 +/- 2 months ... [more ▼]
To study the metabolic effects of normalizing body weight, a frequently sampled iv glucose tolerance test (0.3 g/kg) was performed before [body mass index (BMI), 37.7 +/- 0.5 kg/m2] and 14 +/- 2 months after successful gastroplasty (BMI, 23.7 +/- 0.6 kg/m2) in eight obese women and, for comparison, in eight age- and weight-matched nonobese control women (BMI, 23.6 +/- 0.7 kg/m2). All subjects had normal oral glucose tolerance. The insulin secretion rate (ISR) was derived by deconvolution of plasma C-peptide levels and the insulin MCR (MCRI) by dividing the 0-180 min area under the curve (AUC) of ISR by that of plasma insulin levels (IRI). The insulin sensitivity index (SI) and the glucose effectiveness index (SG) were calculated using Bergman's minimal model. Before gastroplasty, obese subjects showed higher AUC-IRI (P < 0.001) and AUC-ISR (P < 0.02), lower MCRI (P < 0.005) and SI (P < 0.002), but similar SG values, compared to nonobese controls. After gastroplasty, the AUC-IRI dramatically decreased, due to both a reduction of AUC-ISR (from 58,252 +/- 8,437 to 36,675 +/- 4,274 pmol; P < 0.05) and an increase in MCRI (from 658 +/- 117 to 1,299 +/- 127 mL/min.m-2; P < 0.02). SI significantly rose from 4.74 +/- 0.74 to 9.15 +/- 0.96 10(-5) min-1/pmol.L (P < 0.01), whereas SG remained unchanged. All of these parameters became similar to those in nonobese controls (respectively, 32,522 +/- 3,458, 1,180 +/- 101, and 8.48 +/- 1.25; all P = NS). In conclusion, after gastroplasty-induced normalization of body weight, postobese women recover normal insulin secretion, clearance, and action on glucose metabolism. [less ▲]Detailed reference viewed: 18 (1 ULg)
Modified glucagon test allowing simultaneous estimation of insulin secretion and insulin sensitivity: application to obesity, insulin-dependent diabetes mellitus, and noninsulin-dependent diabetes mellitus.
; Scheen, André ; Lefebvre, Pierre
in Journal of Clinical Endocrinology and Metabolism (1995), 80(2), 393-9
The aim of this study was to describe an adaptation of the glucagon test allowing the simultaneous characterization of insulin secretion and sensitivity. A glucagon test (1 mg/m2) was performed in healthy ... [more ▼]
The aim of this study was to describe an adaptation of the glucagon test allowing the simultaneous characterization of insulin secretion and sensitivity. A glucagon test (1 mg/m2) was performed in healthy subjects (n = 11), obese patients (n = 5), insulin-dependent diabetics (n = 9), nonobese noninsulin-dependent diabetics (n = 7), and overweight noninsulin-dependent diabetics (n = 8). Previously, they had been connected to the Biostator, modified for continuous blood collection. Endogenous insulin secretion induced by glucagon was derived from integrated C-peptide concentrations. An index of insulin sensitivity was obtained by dividing the rate of decrease in blood glucose by the total amount of insulin entering the circulation (secreted+infused by the Biostator). The indices of insulin sensitivity obtained in the above groups of subjects were, respectively, 0.064 +/- 0.006, 0.030 +/- 0.006, 0.037 +/- 0.007, 0.021 +/- 0.006, and 0.016 +/- 0.002 mmol/L.U.min (P < 0.001). The estimated insulin secretion values in the 20 min following glucagon injection were, respectively, 0.38 +/- 0.05, 0.65 +/- 0.08, 0.05 +/- 0.01, 0.26 +/- 0.15, and 0.30 +/- 0.07 U (P < 0.001). The insulin sensitivity index obtained from this test correlated with the glucose MCR obtained from a euglycemic glucose clamp (r = 0.816; P < 0.001; n = 12). C-Peptide levels after glucagon administration were also significantly correlated with the estimated endogenous insulin secretion (r = 0.808; P < 0.001; n = 30). This adaptation of the classical glucagon test is an efficient and simple method to simultaneously evaluate insulin secretion and insulin sensitivity. [less ▲]Detailed reference viewed: 55 (0 ULg)
Improving the action of insulin.
Lefebvre, Pierre ; Scheen, André
in Clinical & Investigative Medicine = Médecine Clinique et Experimentale (1995), 18(4), 340-7
Improving the action of insulin is a relatively new concept in diabetes management. Insulin sensitivity can be improved by reduction of excessive body weight, regular physical activity and, possibly, by ... [more ▼]
Improving the action of insulin is a relatively new concept in diabetes management. Insulin sensitivity can be improved by reduction of excessive body weight, regular physical activity and, possibly, by correcting a subclinical magnesium deficiency. Pharmacological means of improving insulin action include metformin, antiobesity serotoninergic agents and, possibly, benfluorex. New compounds aiming at improving the action of insulin are in development and include thiazolidinedione derivatives (known as "insulin sensitizers"), inhibitors of adipose tissue lipolysis (e.g. acipimox), and inhibitors of free fatty acid oxidation (e.g. etomoxir). Avoidance of drugs that reduce insulin sensitivity, such as beta blockers and thiazide diuretics, is recommended. Finally, cigarette smoking is associated with resistance to insulin but it remains to be demonstrated that cessation of cigarette smoking does in fact increase sensitivity to insulin. [less ▲]Detailed reference viewed: 9 (0 ULg)
Short administration of metformin improves insulin sensitivity in android obese subjects with impaired glucose tolerance.
Scheen, André ; Letiexhe, Michel ; Lefebvre, Pierre
in Diabetic Medicine : A Journal of the British Diabetic Association (1995), 12(11), 985-9
In a double-blind, randomized, cross-over study, the metabolic effects of a short treatment with metformin (2 x 850 mg day-1 for 2 days and 850 mg 1 h before evaluation) were compared to those of placebo ... [more ▼]
In a double-blind, randomized, cross-over study, the metabolic effects of a short treatment with metformin (2 x 850 mg day-1 for 2 days and 850 mg 1 h before evaluation) were compared to those of placebo in 15 obese subjects (BMI: 33.2 +/- 0.9 kg m-2), with abdominal distribution of adipose tissue and impaired glucose tolerance. An intravenous glucose tolerance test (0.3 g glucose kg-1) was performed after each period of treatment. Areas under the curve (AUC0-180 min) were calculated for plasma glucose, insulin, and C-peptide levels. Glucose tolerance was estimated by the coefficient of glucose assimilation (KG). Insulin sensitivity (SI) and glucose effectiveness (SG) indices were calculated using Bergman's minimal model. Insulin secretion rate (ISR) was determined by deconvolution of plasma C-peptide levels and insulin metabolic clearance rate (MCR) was estimated by dividing AUC 1SR by AUC insulin. Fasting plasma insulin levels were reduced after metformin (89.3 +/- 15.9 vs 112.4 +/- 24.3 pmol l-1; p = 0.04). AUC glucose, KG and SG were similar in both tests. However, AUC insulin was reduced (39.7 +/- 6.5 vs 51.8 +/- 10.4 nmol min l-1; p = 0.02), while SI (6.98 +/- 1.14 vs 4.61 +/- 0.42 10(-5) min-1 pmol-1 l; p = 0.03) and insulin MCR (715 +/- 116 vs 617 +/- 94 ml min-1 m-2; p = 0.03) were increased after metformin. The demonstration that metformin rapidly improves insulin sensitivity should encourage further research to evaluate the long-term effects of metformin in android obese subjects with impaired oral glucose tolerance. [less ▲]Detailed reference viewed: 19 (1 ULg)
Exogenous glucose oxidation during exercise in relation to the power output.
Pirnay, Freddy ; Scheen, André ; et al
in International Journal of Sports Medicine (1995), 16(7), 456-60
In order to study the influence of the power output on the oxidation rate of exogenous glucose and on the contribution of the various substrates to the energy demand, we combined the use of artificially ... [more ▼]
In order to study the influence of the power output on the oxidation rate of exogenous glucose and on the contribution of the various substrates to the energy demand, we combined the use of artificially enriched 13C-glucose with classical indirect calorimetry during uphill treadmill exercise. Six young male healthy subjects underwent three exercise bouts, in a randomized order and at least two weeks apart, at a low (45% VO2max, 1822 +/- 194 ml O2/min for 4 hours), moderate (60% VO2max, 2582 +/- 226 ml O2/min for 3 hours), and high intensity (75% VO2max, 3036 +/- 287 ml O2/min for 2 hours). After 10 min of exercise, each subject ingested 100 g of artificially 13C-labelled glucose dissolved in 400 ml of water. Over the four hours of the exercise at 45% VO2max, the amount of exogenous glucose oxidized was 89.5 +/- 5.9 g from the 100 g ingested. In all exercise bouts, the oxidation of exogenous glucose already began during the first 30 min after ingestion and peaked at 120 min. The maximum oxidation rates averaged 0.64 +/- 0.07, 0.75 +/- 0.04, and 0.63 +/- 0.08 g/min, and the mean amounts of exogenous glucose oxidized over the first two hours averaged 51.7 +/- 8.0, 61.5 +/- 6.6 and 50.9 +/- 8.45 g, at 45, 60 and 75% VO2max respectively. The contribution of the oxidation of exogenous glucose to the total energy supply progressively decreased when the power output increased, from 19.6 to 12.2%. In the meantime, the contribution of total carbohydrates (exogenous+endogenous) progressively increased from 55.1 to 77.8% while the contribution of lipids decreased from 35.5 to 16.6%. In conclusion, exogenous glucose ingested during exercise is largely oxidized and strongly contributes to the energy supply. The oxidation rate first increases with the power output, but levels off or even decreases at high intensity exercise. [less ▲]Detailed reference viewed: 32 (0 ULg)
Le pied diabétique: etiopathogénie, prévention et traitement
Van Damme, Hendrik ; Paquet, Philippe ; et al
in Revue Médicale de Liège (1994), 49(1), 1-13
-Le pied diabétique est la conséquence des altérations dégénératives du système vasculonerveux observées dans un diabète de longue durée. La neuropathie diabétique est le facteur essentiel dans la plupart ... [more ▼]
-Le pied diabétique est la conséquence des altérations dégénératives du système vasculonerveux observées dans un diabète de longue durée. La neuropathie diabétique est le facteur essentiel dans la plupart des cas, responsable d'hypoalgésies, microtraumatismes et ulcérations, déformation du pied (amyotrophie), et d'une eutosympethectomie (peau sèche, fissurée). Une macroangiopathie (médiacalcinose, occlusions artérielles périphériques) n'est retrouvée que dans 30 % des cas. Une microangiopathie compromet la trophicité des tissus et ralentit leur cicatrisation. Enfin, tout diabétique présente une susceptibilité élevée aux infections. Cette multitude de facteurs en cause impose des mesures de prévention. Un équilibre du profil glycémique retardera les atteintes vasculo-nerveuses. L'hygiène du pied consistera en bains de pieds, soins d'ongles et d'hyperkératoses, chaussures adaptées. En cas de troubles trophiques, une décharge d'appui sers nécessaire. Une désinfection rigoureuse, associée à une antibiothérapie (après prélèvement, si possible) aidera à éviter l'évolution vers l'abcès profond. La moindre collection sera drainée, après excision large des tissus nécrotiques. Les nécroses sèches (talons, orteils) traduisent souvent une artériopethie, pour laquelle un geste de revascularisation (protondoolestie; pontage distal) pourra être pris en considération. Parfois, l'état septique du patient, ou l'étendue de la gangrène, imposera une amputation. L'approche du pied diabétique doit toujours être multidisciplinaire (diabétologue, dermatologue, orthésiste, orthopédiste, chirurgien vasculaire), et doit commencer par des mesures préventives. [less ▲]Detailed reference viewed: 140 (4 ULg)
Estimation de la sensibilité à l'insuline par le "minimal model" : comparaison de différents protocoles d'hyperglycémie provoquée intraveineuse.
SCHEEN, André ; LETIEXHE, Michel ; DUYSINX, Bernard et al
in Diabète & Métabolisme (1994), 20(suppl),Detailed reference viewed: 8 (0 ULg)
Le diabète de type 2 insulino-requérant: caractéristiques des patients et effets de l'insulinothérapie
DUYSINX, Bernard ; SCHEEN, André ; PAQUOT, Nicolas et al
in Diabète & Métabolisme (1994), 20(suppl),Detailed reference viewed: 37 (0 ULg)
Measurement of insulin sensitivity by the minimal model method using a simplified intravenous glucose tolerance test: validity and reproducibility.
Duysinx, Bernard ; Scheen, André ; Gerard, Pascale et al
in Diabète & Métabolisme (1994), 20(4), 425-32
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 ... [more ▼]
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. [less ▲]Detailed reference viewed: 31 (2 ULg)
Measurement of apolipoproteins B and A by radial immunodiffusion: methodological assessment and clinical applications.
; ; Scheen, André et al
in Annales de Biologie Clinique (1994), 52(9), 657-61
The clinical evaluation of apolipoproteins is of interest in order to characterize the risk profile for ischemic heart disease both in normolipidemic and hyperlipidemic subjects. In the non-specialized ... [more ▼]
The clinical evaluation of apolipoproteins is of interest in order to characterize the risk profile for ischemic heart disease both in normolipidemic and hyperlipidemic subjects. In the non-specialized and/or small practice clinical laboratory, the measurement of some apolipoproteins can be undertaken by simple methods of immunological analysis, among which radial immunodiffusion can be of interest due to its simplicity of use and because it does not require specific equipment. In this work several methodological questions concerning the measurement of plasma apolipoproteins B and A by radial immunodiffusion have been addressed; the results show that this method is particularly reliable for the apo B assay. Regression analysis between values obtained with radial immunodiffusion and radioimmunoassay was r = 0.972 for apo B and r = 0.782 for apo A. The recovery rate was above 90% for both apolipoproteins (93.8% for apo B and 99.5% for apo A). The inter and intraassay coefficients of variation were below 5%, and the detection limits were estimated as 9.6 mg/dl for apo A and 6.9 mg/dl for apo B. Neither the ingestion of a standard breakfast (500 Cal, 17 g fat, 120 mg cholesterol) 2 h prior to testing nor freezing the sample significantly affected the measurement of apolipoproteins B and A. Mean plasma concentrations of both apolipoproteins measured by radial immunodiffusion in normo and hyperlipidemic subjects are also presented. [less ▲]Detailed reference viewed: 15 (0 ULg)