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Biomedical subjects

A Scheen

Publications and source records attributed to A Scheen.

At least 55 records · Page 3Linked to original sources
PubMed1985

[Drug update].

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Drug Therapy↗
PubMed1985

Insulin-stimulated glucose disposal is not increased in anorexia nervosa.

Insulin-stimulated glucose disposal was investigated using the euglycemic hyperinsulinemic glucose clamp technique in six women with anorexia nervosa (27.3 +/- 4.9 yr old; weight, 38.8 +/- 6.6 kg) and compared to results obtained in six normal women (22.6 +/- 1.2 yr old; weight, 58 +/- 2.5 kg) and seven obese women (26.8 +/- 7.7 yr old; weight, 92.5 +/- 13.8 kg). The glucose clamp was performed for 2 h using the Biostator and a continuous insulin infusion of 100 mU kg-1 h-1. Plasma levels of insulin were determined at 30-min intervals. Plasma levels of glucagon, FFA, glycerol, 3-hydroxy-butyrate, and alanine were measured basally. Blood glucose levels were similar in normal subjects and anorectic patients; they were slightly but significantly higher in the obese patients. The indices of insulin sensitivity measured were the MCR of glucose and the ratio of glucose infused to insulin infused (G/I). They were very similar in anorectic subjects [MCR, 13.5 +/- 2.4 (+/- SEM) ml kg-1 min-1; G/I, 5.2 +/- 0.9 mg/mU) and normal subjects (MCR, 13.5 +/- 1.7 ml kg-1 min-1; G/I, 5.2 +/- 0.4 mg/mU), but were significantly reduced in obese patients (MCR, 5.1 +/- 0.8 ml kg-1 min-1; G/I, 2.6 +/- 0.3 mg/mU; P less than 0.0025). Differences in plasma insulin among the three groups were not statistically significant. Plasma alanine levels were higher in anorectic than in normal or obese subjects, suggesting defective gluconeogenesis. Thus, insulin-stimulated glucose disposal is normal in patients with anorexia nervosa, a finding that contrasts with the previously reported increase in erythrocyte insulin receptors in this disease.

3-Hydroxybutyric Acid↗
PubMed1984

[Current therapeutics].

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Drug-Related Side Effects and Adverse Reactions↗
PubMed1983

A 6-hour nocturnal interruption of a continuous subcutaneous insulin infusion: 1. Metabolic and hormonal consequences and scheme for a prompt return to adequate control.

Interruption of a continuous subcutaneous insulin infusion, most often due to technical problems occurring during the night, is a not uncommon event whose metabolic consequences have received relatively little attention until now. We have therefore investigated the changes in blood glucose, plasma non-esterified fatty acids, 3-hydroxybutyrate, glucagon and free insulin in eight C-peptide negative Type 1 diabetic patients whose pumps were deliberately stopped between 23.00 h and 05.00 h. A control test with the pump functioning normally was carried out in each patient and the studies were randomized. Considering the values at 23.00 h as reference, interruption of the insulin infusion resulted in (1) a rapid decrease in plasma free insulin significant after 1 h and reaching a nadir of 6 +/- 2 mU/l after 6 h; (2) a rise in blood glucose which was significant at hour 3 and reached 17.4 +/- 1.9 mmol/l at hour 6; (3) a moderate increase in plasma nonesterified fatty acids which remained in the range of 700-800 mumol/l; (4) an early and linear rise in plasma 3-hydroxybutyrate, significant after 1 h and averaging 1290 +/- 140 mumol/l after 6 h; (5) a late increase (hour 5) in plasma glucagon. The second aim of our study was to provide for the patient a precise scheme of insulin supplements administered via the pump and based on blood glucose monitoring (Dextrostix - Glucometer) and semi-quantitative evaluation of ketonuria (Acetest). Resetting the pump at its basal rate at 05.00 h and giving insulin supplements (2-8 U) at 06.45 h (with the usual breakfast dose) and again at 10.00 h have proved efficacious in restoring satisfactory metabolic control by noon the day after starting the experiment. These results form practical recommendations to patients undergoing this type of accident.

3-Hydroxybutyric Acid↗
PubMed1983

[A reduction in the hyperventilation threshold by intravenous infusion of adrenaline in the treadmill exercise].

Seven healthy male subjects underwent a treadmill incremental work test in control conditions and during an intravenous epinephrine infusion (10 micrograms/min). At all exercise intensities, epinephrine increased heart rate, ventilation, respiratory quotient and plasma lactate levels without significant changes in oxygen consumption. Under epinephrine infusion, the "anaerobic threshold", considered as the critical intensity at which ventilation began to increase non linearly with oxygen consumption, appeared at a lower intensity and for a higher plasma lactate level than in control conditions. We conclude that the hyperventilation threshold does not necessarily reflect a muscular hypoxia. It could be due to an effect of catecholamines on peripheral chemoreceptors, maybe by alpha-adrenergic vasoconstriction in the carotid bodies.

Blood Pressure↗
PubMed1982

Effect of protein-supplemented fasting on metabolic and hormonal responses to epinephrine infusion in obese subjects.

The present study aimed at investigating the effects of an epinephrine (EPI) intravenous infusion (10 micrograms/min for 30 min) in normal subjects and in obese patients before and after 13 days of protein-supplemented fasting (PSF, 70 g protein/day). Blood glucose, plasma free fatty acids (FFA), lactate, insulin (IRI) and glucagon were determined before, during (15, 30 min) and after (+30 and +60 min) the EPI infusion. 1. When compared to lean control subjects, obese patients exhibited a less marked rise in blood glucose and a more important increase in plasma FFA, EPI infusion decreased IRI plasma levels in normals but not in the obese. Plasma glucagon was lower in the obese under basal conditions and their A cell reactivity to EPI was clearly reduced. 2. Comparison of the results obtained in obese patients before and after PSF revealed that EPI-induced blood glucose rise was not altered despite lower basal values after PSF. Plasma lactate response was impaired, probably because of the depletion in muscle glycogen. Reduction in basal plasma IRI was associated with a significantly higher FFA mobilization. Abnormally low basal EPI-stimulated glucagon concentrations persisted after PSF despite concomitant reductions in blood glucose and plasma IRI.

Adult↗
PubMed1982

[Effects of a hypocaloric protein diet on changes in arterial pressure produced by adrenaline infusion].

In 9 obese patients, epinephrine infusion (10 microgram/min) did not significantly modify the mean arterial blood pressure (MBP) in basal conditions. This infusion reduced MBP (-7 mm Hg, p less than 0.05) after 13 days of protein-supplemented fasting. This difference in the cardio-vascular reactivity to circulatory epinephrine could contribute to the decrease in the arterial blood pressure observed during protein-supplemented fasting.

Blood Pressure↗
PubMed1981

Critical analysis of the "anaerobic threshold" during exercise at constant workloads.

The method described by Wasserman for anaerobic threshold (AT) determination, based on the recording of ventilatory parameters, was supported by the simultaneous appearance of hyperlactacidemia and hyperventilation during a standardized incremental work test. Our study aimed at testing the AT in another profile of exercise, viz., during exercises at constant workloads. A homogenous population of 66 healthy subjects performed on a treadmill a total of 100 exercises of 20 min duration at constant workloads (43, 48, 52, 57, 63, and 71% VO2 max). The VO2, V, and venous plasma lactic acid (LA) were determined every minute. LA showed an initial transient increase at 43% VO2 max and a steady-state elevated level above 48% VO2 max. In contrast, the hyperventilation threshold (HVT) was only observed above 57% VO2 max, simultaneously with a delayed steady-state VO2 and with a sustained increase of lactate until the end of exercise. The meaning of the simultaneity of these three events must still be studied. However, the dissociation between both early and steady-state lactate thresholds and HVT is not in keeping with the concept of AT. In these conditions, there is no evidence that HVT necessarily represents an AT, viz., a critical intensity of exercise inducing an insufficient oxygen delivery to the muscles. This conclusion does not imply that the measurement of HVT should be rejected as an empirical test of physical fitness.

Adult↗
PubMed1981

Cardiovascular effects of intravenous tolmesoxide in hypertensive patients.

Tolmesoxide, a potent vasodilating compound, was infused intravenously (0.5 to 3.5 mg/kg b.w., rate of infusion: 2.5 to 10.0 mg/min during 7--25 min, 2 or 3 successive infusions separated by a 30 min rest period) in 7 hypertensive patients. An abrupt fall in blood pressure and heart rate occurred in 4 patients whereas 2 patients exhibited almost no hemodynamic response. The remaining case suffering from renovascular hypertension responded with a progressive dose-dependent decrease in blood pressure. No obvious correlation could be demonstrated between the drug plasma levels (ranging between 1.0 and 11.1 microgram/ml) and the hemodynamic effects among the 7 patients studied.

Adult↗
PubMed1981

[Decreased secretion of epinephrine during protein-supplemented fasting in obese subjects (author's transl)].

The protein-supplemented fasting induces a progressive but moderate decrease in blood glucose (-26%) and a marked rise in plasma free fatty acids levels (+ 43%). Nevertheless the secretion of epinephrine by the adrenal medulla, as indirectly estimated by the ratio of the basal urinary elimination to the recovery percentage from the urine of an epinephrine infusion, shows a significant decrease (- 36%) during the protein diet. Thus the enhanced lipolysis does not result from an adrenergic overactivity but merely depends upon the marked reduction in the plasma insulin level (- 38%).

Adrenal Medulla↗