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A Wirth

Publications and source records attributed to A Wirth.

At least 91 records · Page 5Linked to original sources
PubMed1991

Fatty acids in the portal vein of the rat regulate hepatic insulin clearance.

The effects of FFA on hepatic insulin clearance were studied in the in situ perfused rat liver. Clearance decreased with increasing body weight (age) of the rats. When FFA were added to the perfusate a 40% reduction of hepatic removal of insulin was found over the normal, physiological range (less than 1,000 mumol/liter), less pronounced in heavier rats. When perfusion was started with high concentrations of FFA, inhibition was rapidly reversible, a phenomenon again blunted in heavier rats. In contrast to FFA, different glucose concentrations in the perfusate did not affect the hepatic insulin uptake in the presence of FFA within physiological concentrations. Thus, hepatic clearance of insulin is proportional to rat weight (age) and portal FFA concentrations. Other studies have recently shown that fatty acids inhibit insulin binding, degradation, and function in isolated rat hepatocytes, and that hepatic clearance is inversely dependent on hepatic triglyceride concentrations, both inhibitions reversible by prevention of fatty acid oxidation. It is suggested that the diminished hepatic clearance of insulin in heavier (older) rats is at least partly due to their relative obesity and increased hepatic triglyceride contents. This effect as well as that of portal FFA is probably mediated via fatty acid oxidation in the liver. This mechanism may have implications for the regulation of hepatic metabolism, and peripheral insulin concentrations.

Animals↗
PubMed1990

[Sex-specific changes in body composition during weight reduction].

The aim of this study was to ascertain whether overweight men and women of comparable age, body surface area and weight would display any differences in weight loss or changes in body composition while receiving identical calorie intakes. 15 men and 15 women of mean age 46.7 (26-57) years with obesity (body mass index 29-36 kg/m2) were given a reducing diet containing 700 kcal/d for 4 weeks. The two groups were identical in age, body weight and height. The change in body composition was studied by means of ultrasound and nitrogen balance. The women had thicker layers of subcutaneous fat (241 +/- 8 mm) over all parts of the body than the men (137 +/- 10 mm) (summated measurements at 14 points). Among the men body weight fell from 93.1 +/- 2.1 to 83.8 +/- 2.0 kg, but the women declined only from 92.9 +/- 2.0 to 84.7 +/- 1.9 kg. Although men achieved a greater weight loss (13%; P less than 0.001) the decrease in their subcutaneous fat layer was 33% less (to 117 +/- 9 mm) than in the women (211 +/- 8 mm). Cumulative nitrogen balance among the men was 4.7 times more negative than in women (-104 +/- 14 g versus -22 +/- 11 g); this points to accentuated muscle breakdown. More fat was mobilized in the women than in the men, chiefly from the regions of the limbs and hips.

Adipose Tissue↗
PubMed1990

Multichannel biomagnetic system for study of electrical activity in the brain and heart.

The authors designed a multichannel system for noninvasive measurement of the extremely weak magnetic fields generated by the brain and the heart. It uses a flat array of 37 superconducting magnetic field-sensing coils connected to sophisticated superconducting quantum interference devices. To prevent interference from external electromagnetic fields, the system is operated inside a shielded room. Complete sets of coherent data, even from spontaneous events, can be recorded. System performance was evaluated with phantom measurements and evoked-response studies. A spatial resolution of a few millimeters and a temporal resolution of a millisecond were obtained. First results in patients with partial epilepsy and investigations of the cardiac conductive pathway indicate that biomagnetism is now ready for a systematic clinical evaluation. Interpretation of measurements was facilitated by highlighting biomagnetically localized electrical activity in three-dimensional digital magnetic resonance images.

Brain↗
PubMed1990

[AIDS information].

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1990

[Focus of criticism--inpatient rehabilitation].

Inpatient rehabilitation has become an integral part of our health system. Whereas this development strikes a mood of optimism, it also raises several problems. These are mainly in respect of the selection of patients, the duration of the rehabilitation measure, the integration of family members and relatives, and the aftercare period. We are still without an adequate concept of rehabilitation and we lack a delineation between prevention, cure treatment and acute treatment methods. This lack of a clear approach makes systematic rehabilitation research absolutely mandatory.

Chronic Disease↗
PubMed1988

Treatment of coronary heart disease by diet and exercise: fasting and diurnal lipoproteins.

The effects of a combined exercise and low-fat dietary regimen were studied in 11 patients with angiographically documented coronary heart disease (cholesterol 233 mg/dl, triglycerides 158 mg/dl) and 13 comparable patients (cholesterol 224 mg/dl, triglycerides 174 mg/dl) on usual care. During one year, fasting serum lipoproteins were lowered to "ideal" levels in the intervention group (cholesterol 191 mg/dl, triglycerides 100 mg/dl, LDL-cholesterol 121 mg/dl). There was no change of triglycerides and cholesterol on usual care while LDL-cholesterol rose significantly. Neither regimen had any effect on HDL-cholesterol. Diurnal triglycerides as a presumptive measure of IDL in the intervention group were diminished by 39%. The study demonstrates the feasibility of a diet and exercise regimen to normalize mildly elevated plasma lipid levels and thus to possibly affect the course of coronary heart disease without drugs.

Cholesterol↗
PubMed1988

Is taurine a marker for retinitis pigmentosa?

In view of contrary reports in the literature on anomalies of taurine concentration in the blood of retinitis pigmentosa patients, taurine clearance has been determined in 19 patients and 17 controls. No significant difference has been found between the average values of the two populations. The taurine content in cataractous crystalline lenses of retinitis pigmentosa patients has been found higher than the taurine content in lenses with senile cataract, but the same behaviour was also shown by five selected proteogenic amino acids. The results are discussed together with related literature data to conclude that taurine can be involved at least in some subtypes of retinitis pigmentosa, but cannot be considered as a marker for the disease.

Adolescent↗
PubMed1988

Low-fat diet and regular, supervised physical exercise in patients with symptomatic coronary artery disease: reduction of stress-induced myocardial ischemia.

The effects of physical exercise and normalization of serum lipoproteins on stress-induced myocardial ischemia were studied in 18 patients with coronary artery disease, stable angina pectoris, and mild hypercholesterolemia (total serum cholesterol 242 +/- 32 mg/dl). These patients underwent a combined regimen of low-fat/low-cholesterol diet and regular, supervised physical exercise at high intensity for 12 months. At 1 year serum lipoproteins has been lowered to ideal levels (serum cholesterol 202 +/- 31 mg/dl, low-density lipoproteins 130 +/- 30 mg/dl, very low-density lipoproteins 22 +/- 15 mg/dl, serum triglycerides 105 [69 to 304] mg/dl) and physical work capacity was improved by 21% (p less than .01). No significant effect was noted on high-density lipoproteins, probably as a result of the low-fat/high-carbohydrate diet. Stress-induced myocardial ischemia, as assessed by thallium-201 scintigraphy, was decreased by 54% (p less than .05) despite higher myocardial oxygen consumption. Eighteen patients matched for age and severity of coronary artery disease served as a control group and "usual medical care" was rendered by their private physicians. No significant changes with respect to serum lipoproteins, physical work capacity, maximal rate-pressure product, or stress-induced myocardial ischemia were observed in this group. These data indicate that regular physical exercise at high intensity, lowered body weight, and normalization of serum lipoproteins may alleviate compromised myocardial perfusion during stress.

Body Weight↗
PubMed1987

Metabolic effects and body fat mass changes in obese subjects on a very-low-calorie diet with and without intensive physical training.

During 4 weeks, 40 obese subjects (body mass index 30-45 W/H2) were treated with a 300-kcal mixed diet alone or in combination with exercise training on a bicycle ergometer in a metabolic ward. Exercise had a minor effect on body weight, reflected by an additional fat loss of 1.7 kg (expected loss: 4.0 kg). Hyperinsulinemia was improved by diet and normalized by diet combined with exercise; a similar effect was observed regarding C-peptide levels. Plasma concentrations of epinephrine and norepinephrine decreased in both groups. At maximal work, norepinephrine levels were higher in the group with exercise. Free fatty acids and free glycerol increased at rest as well as during exercise in subjects on both regimens, the difference being more pronounced in the exercise group. Enhanced oxidation of fat was substantiated by lower respiratory quotients during endurance exercise. Working capacity increased and blood pressure decreased considerably as a consequence of physical training. It is concluded that exercise training in addition to a hypocaloric diet lowers body weight and body fat, although to a lower degree than expected. During and following bouts of exercise, fat mobilization and oxidation is enhanced, but these effects are probably counteracted at rest. On the other hand, the diet-induced deterioration of physical performance is overcompensated.

Adipose Tissue↗
PubMed1986

[Combination therapy of obesity with a reducing diet and physical training. Cardiovascular and metabolic effects].

Twenty obese patients were either given a caloric restricted diet (300 kcal/d) over 4 weeks alone or underwent an additional ergometer exercise programme for up to 2 hours daily. Combination therapy resulted in an improvement of physical performance by 26% despite weight loss of 11 kg. Blood pressure could be reduced both at rest and on exercise. Blood pressure regulation and heart rate under orthostatic conditions remained unchanged for both therapeutical approaches. The effect on carbohydrate and lipid metabolism was also more favorable in patients on combination therapy than in those given a reduction diet alone. Combination of reduction diet and physical exercise is therefore superior to caloric restriction alone with regard to cardiovascular and metabolic considerations.

Adult↗
PubMed1985

[Pseudohypertriglyceridemia in glycerokinase deficiency].

Falsely high serum triglyceride concentrations (410-850 mg/dl) were measured in four members of a family of five from Franconia in Germany. The cause was hyperglyceridaemia on the basis of glycerol kinase deficiency. None had any symptoms and no other metabolic anomaly was demonstrated. The possibility of glycerol kinase deficiency should be considered in any case of elevated serum triglyceride concentration but with clear serum, normal lipid electrophoresis and lack of response to lipid-lowering measures.

Adult↗
PubMed1985

Training-induced changes in serum lipids, fat tolerance, and adipose tissue metabolism in patients with hypertriglyceridemia.

Ten males (mean age 44 years) with primary hypertriglyceridemia were trained for 4 months 3 times/week for 1-h sessions. Eleven patients with similar physical characteristics and hypertriglyceridemia served as controls. Serum was assayed for TG and cholesterol (CH) and the various lipoprotein fractions, apoprotein A-I, glucose, insulin, and C-peptide. The removal of TG from the circulation was estimated by the Intralipid test. An open fat biopsy was taken and the incorporation and esterification of [14C]palmitate and glycerol release were measured in vitro. Following endurance physical training, serum TG and VLDL-TG decreased by 25 and 27%, respectively. No changes were observed in total CH and CH in the lipoprotein fractions or in apoprotein A-I. Fat tolerance increased slightly (+8%) whereas the incorporation of labelled palmitate into adipose tissue was reduced by 16%. The diminished incorporation was concomitant with a reduction in the esterification of fatty acids to TG (-29%). Enhanced removal of TG may contribute to the lowering of serum TG. The skeletal muscle is probably responsible for this adaptation, whereas the uptake of TG into adipose tissue is diminished.

Adipose Tissue↗
PubMed1985

Adrenergic regulation of lipolysis in abdominal adipocytes of obese subjects during caloric restriction: reversal of catecholamine action caused by relief of endogenous inhibition.

The effects of adrenaline, noradrenaline, and of the alpha 2- and beta-selective agonists clonidine and isoproterenol were studied in fifteen obese subjects before and after 4 weeks of caloric restriction (300 cal day-1). Basal glycerol release averaged 1.4 mumol (10(6) cells)-1 (180 min)-1 before starvation and 2.8 mumol (10(6) cells)-1 (180 min)-1 during starvation (P less than or equal to 0.1). Before starvation adrenaline and noradrenaline caused a 2-3-fold increase of glycerol release. This lipolytic effect disappeared during starvation. An inhibitory effect of adrenaline was observed instead which was maximal at an adrenaline concentration of 1 mumol 1(-1) (P less than or equal to 0.05). The dose-response relationships of the alpha 2- and beta-selective agents clonidine and isoproterenol were not appreciably changed by caloric restriction. The increase of basal lipolytic rate and the reversal of adrenaline action seen during caloric restriction could be mimicked by removal of endogenous adenosine using adenosine deaminase (1.6 microgram ml-1). In addition, inclusion of N6-phenylisopropyladenosine (1 mumol 1(-1)) into the medium reverted the adrenaline-induced inhibition seen during caloric restriction. The results suggest that local modulators such as adenosine are of primary importance for the apparent change of responsiveness to adrenaline and noradrenaline seen during starvation of human fat cells in vitro.

Adenosine↗
PubMed1984

Diminished insulin receptors on monocytes and erythrocytes in hypertriglyceridemia.

Carbohydrate intolerance is a common observation in endogenous hypertriglyceridemia (HL). So far the nature of this metabolic defect, which accompanies postprandial hyperinsulinemia and a reduced hypoglycemic action of insulin, has not been elucidated. We have examined cellular insulin binding in 20 subjects affected with HL (average plasma triglyceride level, 437 +/- 311 mg/dL) to test the possibility that a receptor defect is involved in peripheral insulin resistance. Monocytes from the HL subjects bound, on the average, 34% less insulin than cells from eight normotriglyceridemic controls of comparable age and body weight (average plasma TG level, 169 +/- 34 mg/dL). Likewise, erythrocytes from the HL group bound 29.6% less insulin than did those from control subjects. Scatchard analysis of the binding data revealed that the number of insulin receptors was reduced for both types of cells. To test if the abnormality in cellular insulin-binding capacity in these subjects is an inherent defect or secondary to the hypertriglyceridemia, 11 of the subjects participated in a 4-month training program (120 minutes weekly of moderate exercise at 60% VO2 max), while the remaining nine persons served as controls. Training reduced the average plasma TG level from 373 +/- 270 to 277 +/- 139 mg/dL (P less than 0.01), but cellular insulin binding was not significantly affected. In addition, no correlation was found between the individual TG plasma concentration and cellular insulin binding. Thus, training itself also proved ineffective in enhancing insulin binding, most probably due to exertion of insufficient intensity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗