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Biomedical subjects

M Halle

Publications and source records attributed to M Halle.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Effect if 6-week nutritional intervention with enzymatic yeast cells and antioxidants on exercise stress and antioxidant status].

The aim of the present study was to investigate the influence of a yeast cell preparation rich in antioxidant vitamins, antioxidant enzymes, trace elements and minerals on the exercise-induced stress reaction and antioxidant status. The study was carried out in a non-blinded, controlled design. After a 6 week pre-ingestion period, 9 highly endurance-trained athletes took the preparation twice daily for another 6 weeks. After each phase venous blood samples were drawn in the resting state after an overnight fast followed by a strenuous 15 km cross country race. 1 h after the exercise venous blood sampling was repeated. Compared to the pre-ingestion period, the following significant alterations could be detected after 6 weeks of ingestion: 1) In the resting state, soluble interleukin-2 receptor (p < 0.05) and plasma fibrinogen (p < 0.01) were shown to be lower whereas plasma fibronectin was increased (p < 0.01). 2) 1 h after the race the significant difference in fibrinogen and fibronectin was confirmed. In addition myoglobin (p < 0.01) and CKMM3 (p < 0.05) as well as mangan superoxid dismutase (p < 0.05) were reduced. In conclusion, the 6-week ingestion-period resulted in an improvement of the systemic and muscular stress reaction. In addition, the decrease in mangan superoxide dismutase concentration can be interpreted as a sign of reduced free radical stress. However, these preliminary results have to be confirmed in larger trials in blinded designs. In addition, there seems to be a rationale for testing the effects of yeast-cell preparations in patients with chronic degenerative diseases as some of the investigated parameters are involved in the pathophysiology of such illnesses.

Adult↗
PubMed1998

[LDL subfractions and coronary heart disease--an overview].

Low density lipoproteins are heterogeneous in particle size, density, and physical as well as chemical properties. Regarding size and density, LDL can be divided into two main profiles, LDL pattern A with elevated concentration of large, buoyant LDL particles and LDL pattern B with increased concentration of small, dense LDL particles. The latter is particularly expressed in insulin resistance and is associated with elevated serum triglycerides and reduced concentrations of HDL and particularly HDL2 cholesterol. The LDL profile of increased concentration of small, dense LDL particles has shown to be associated with an increased risk of cardiovascular events. The LDL profile is partly genetically determined, but can be improved by non-pharmacological (exercise, diet) and pharmacological intervention. It remains to be confirmed whether the LDL subfraction profile is an independent lipid risk factor besides HDL2 cholesterol and triglycerides, but it is certainly a valuable indicator assessing metabolic cardiovascular risk.

Cholesterol, HDL↗
PubMed1998

[Importance of increased physical activity in ambulatory cardiovascular prevention].

Current trends in public health provided potential arguments to, first, intensify the recommendations of a physically active lifestyle in the primary prevention of atherosclerosis and, second, to prescribe a supervised outpatient exercise training program for secondary prevention of cardiovascular diseases. Regular physical exercise may positively influence cardiovascular risk factors (overweight, hypertension, hyperlipoproteinaemia, insulin resistance, hemostatic markers). Physical conditioning modifies the body composition in favor of an increased skeletal muscle mass, changes the eating habits, and other life style characteristics. The dietary modifications characterized by a low-fat, more vegetarian food supports the weight control and the adjustment of the other metabolic risk factors. All these changes are suitable to reduce the manifestation of atherosclerosis and to minimize the risk of an acute thromboembolic arterial occlusion. Physical conditioning on one's own initiative in primary prevention or an exercise training program supervised by health professionals in secondary prevention of atherosclerosis should predominantly include a low intensive aerobic endurance exercise training. Lactate concentration in capillary blood can be measured to objectify and regulate exercise intensity. The additional energy turnover should amount to a minimum of 1,000 kcal and a maximum of 3,500 kcal weekly. This energy expenditure could be realized either with an increased physical activity level in daily routine (e.g., stair climbing, go for a walk, gardening) or by a regular leisure-time physical exercise. A turnover of 300 kcal per session should be prescribed. In long-term clinical trials investigating the benefit of primary and secondary cardiovascular prevention a reduction of the cardiovascular mortality of about 20-30% has been demonstrated.

Cardiovascular Diseases↗
PubMed1998

[Sports in the heart rehabilitation group--experiences with ambulatory rehabilitation at home].

Regular physical exercise has shown to be beneficial for patients with cardiovascular disease. Therefore cardiac rehabilitation in Germany is continued for years after hospital discharge in outpatient cardiac exercise groups which meet twice a week under the guidance of a physician and a sports instructor. Before participation cardiac patients have to be examined including exercise tests and echocardiography for assessment of contraindications for exercise therapy as well as individual exercise capacity. Patients are assigned to two groups with different levels of exercise intensity according to their symptom-free work-capacity (cutoff level 1 W/kg). During exercise sessions sports-specific forms of exercise such as stretching, aerobic exercise or ball games are accompanied by psychosocial elements such as stress management. This global approach is intended to improve cardiovascular risk factors, cardiac function, and work capacity as well as to stabilize the patient psychologically in order to accelerate social integration. Recently these groups have opened towards patients after cardiac transplantation or with severe heart failure. Therefore, cardiac exercise groups play a central role in cardiac rehabilitation long after the acute cardiac event.

Ambulatory Care↗
PubMed1998

Importance of TNF-alpha and leptin in obesity and insulin resistance: a hypothesis on the impact of physical exercise.

Obesity is associated with an increased incidence of insulin resistance, dyslipoproteinemia, and hypercoagulability. In a more recently established hypothesis of body weight control and regulation of metabolism, the adipocyte secretes leptin and locally expresses TNF-alpha, the latter being responsible for the expression of metabolic cardiovascular risk factors. TNF-a mRNA expression and TNF-alpha protein are greatly increased in adipose tissue from obese animals and humans. Elevated TNF-alpha expression induces insulin resistance by downregulating the tyrosine kinase activity of the insulin receptor and decreasing the expression of GLUT-4 glucose transporters. TNF-alpha also reduces lipoprotein lipase activity in white adipocytes, stimulates hepatic lipolysis, and increases plasminogen activator inhibitor-1 content in adipocytes. Moreover, adipocytes secrete leptin, a molecule with a secondary cytokine structure whose concentrations correlate with the amount of fat tissue. Increased leptin levels downregulate appetite and increase sympathetic activity and thermogenesis in the hypothalamus. Diet-induced weight loss reduces adipose TNF-alpha expression and serum leptin levels and is associated with improved insulin sensitivity and lipid metabolism. Although exercise has also been shown to reduce leptin levels, an influence on TNF-a expression in adipocytes or muscle cells has not yet been demonstrated.

Animals↗
PubMed1997

Physical activity and lipoprotein metabolism: epidemiological evidence and clinical trials.

Prospective epidemiological studies have proven a close link between the lipoprotein profile and cardiovascular morbidity and mortality. As physical activity is accepted as a significant factor improving physical fitness and lipoprotein metabolism, there is evidence that physically active men have a lower cardiovascular risk due to their higher metabolic fitness. Physical activity and physical fitness are generally linked to higher HDL cholesterol and lower LDL cholesterol as well as lower triglyceride and insulin levels. However, in cross-sectional studies the differences in lipoprotein cholesterol evaluated by routine measures in healthy physically active individuals and sedentary controls are only minor compared to therapeutical aims. The impact of exercise and training is often more significant when the effect of exercise on lipoprotein subfractions and apolipoprotein levels are taken into account. Dramatic differences can be documented in concentrations of cardioprotective HDL subset2 and atherogenic small, dense LDL subset6 levels in relation to the individual status of aerobic fitness and body composition in adults. These observations indicate that the preventive and therapeutical use of physical activity is of particular significance in a population of cardiovascular risk or patients with reduced daily activity. Our own experience in clinical trials shows that even in short-term programs (4 weeks to 6 months) changes in activity and eating behavior may lead to important improvements of the metabolic risk and lipid profile. Understanding the complex interaction between exercise and metabolic control of the lipid profile as well as the correlation with other risk parameters will improve the knowledge of prescribing exercise programs in patients at risk.

Adult↗
PubMed1997

Relationship of serum ferritin concentrations with metabolic cardiovascular risk factors in men without evidence for coronary artery disease.

Elevated serum ferritin concentrations between 200 and 500 microg/l have been found to be a strong risk factor for acute myocardial infarction in Finnish men, but the reason for this association is still uncertain. In the Finnish population ferritin concentrations correlated with factors of insulin resistance syndrome. As these factors have been found to be associated with an LDL subfraction phenotype of increased concentrations of small, dense LDL particles, we hypothesized an association between ferritin and an atherogenic LDL subfraction profile, a finding which could be an explanation for the observed relationship between ferritin and atherosclerosis. Therefore we determined serum ferritin levels, metabolic cardiovascular risk factors, and the LDL subfraction phenotype in 93 healthy men without signs for infection or coronary heart disease. We found that men with moderately elevated ferritin levels (200-500 microg/l; n = 31) had a significantly worse coronary risk profile than men with lower levels ( < 200 microg/l; n = 62). Elevated ferritin concentrations were associated with significantly higher values for serum triglycerides, VLDL cholesterol, VLDL apolipoprotein B (P < 0.01), IDL cholesterol, fasting glucose (P < 0.05) and uric acid (P < 0.01), and lower levels for HDL2b and HDL2a cholesterol and apolipoprotein A-I (P < 0.05), and lipoprotein(a) (P < 0.01). Elevated ferritin levels were, however, not associated with an unfavourable LDL subfraction profile of increased concentrations of small, dense LDL particles.

Adult↗
PubMed1997

Differences in the concentration and composition of low-density lipoprotein subfraction particles between sedentary and trained hypercholesterolemic men.

There is evidence that a low-density lipoprotein (LDL) subfraction profile of increased concentrations of small, dense LDL particles is less common among trained than among sedentary normocholesterolemic men, but it is still uncertain whether there is a similar association in hypercholesterolemia also. Therefore, we determined the lipid and apolipoprotein concentration and composition of six LDL subfractions (density gradient ultracentrifugation) in 20 physically fit, regularly exercising (>three times per week) hypercholesterolemic men and 20 sedentary hypercholesterolemic controls. Trained (maximal oxygen consumption [VO2max], 57.3 +/- 7.4 mL/kg/min) and sedentary (VO2max, 37.5 +/- 8.8 mL/kg/min) individuals (aged 35 +/- 11 years; body mass index [BMI], 23.9 +/- 2.7 kg/m2) were matched for LDL apolipoprotein (apo) B levels (108 +/- 23 and 112 +/- 36 mg/dL, respectively). Trained subjects had significantly lower serum triglyceride (P < .05) and very-low-density lipoprotein (VLDL) cholesterol levels (P < .05) and higher high-density lipoprotein 2 (HDL2) cholesterol levels (P < .01) than sedentary controls. LDL particle distribution showed that trained individuals had significantly less small, dense LDL (d = 1.040 to 1.063 g/mL) and more large LDL (d = 1.019 to 1.037 g/mL) subfraction particles than sedentary controls, despite equal total LDL particle number. Analysis of LDL composition showed that LDL particles of hypercholesterolemic trained men had a higher free cholesterol content than LDL of untrained hypercholesterolemic men. Small, dense LDL in hypercholesterolemic trained men were richer in phospholipids than those in sedentary controls. These data demonstrate the significant influence of aerobic fitness on lipoprotein subfraction concentration and composition, thereby emphasizing the role of exercise in the treatment and risk reduction of hypercholesterolemia.

Centrifugation, Density Gradient↗
PubMed1997

Lipoprotein(a) selectively impairs receptor-mediated endothelial vasodilator function of the human coronary circulation.

OBJECTIVES: We investigated the influence of lipoprotein(a) [Lp(a)] serum levels on different endothelium-dependent vasodilator stimuli representing different mechanisms of endothelium-dependent vasodilation. BACKGROUND: Lp(a) is an independent predictor for the development and progression of coronary artery disease. Impairment of endothelium-dependent vasodilation of epicardial arteries has been shown in patients with high levels of Lp(a). METHODS: In 108 patients with angiographically normal or minimally diseased coronary vessels, vasomotor responses to acetylcholine, cold pressor testing, increased blood flow and nitroglycerin were assessed. RESULTS: Lp(a) levels > or = 30 mg/dl were associated with significant dose-dependent enhancement of the vasoconstrictor response to acetylcholine [receptor-mediated vasodilation, p = 0.002; acetylcholine 10(-6) mol/liter, -29 +/- 21% vasoconstriction with Lp(a) levels > or = 30 mg/dl vs, -5.6 +/- 25% with Lp(a) levels < 30 mg/dl]. In addition, vasoconstrictor response to cold pressor test (receptor- and flow-mediated vasodilation) was significantly enhanced in patients with Lp(a) levels > or = 30 mg/dl (-13 +/- 12% vs. 1.2 +/- 16%, p = 0.005). In contrast, strictly endothelium-dependent, but non-receptor-mediated, flow-dependent dilation and endothelium-independent dilation with nitroglycerin were not compromised. Linear regression analysis revealed an inverse relation between Lp(a) and both acetylcholine-induced (r = -0.34, p = 0.0007) and cold pressor test-induced (r = -0.44, p = 0.0001) vasodilation. By multivariate analysis, Lp(a) was a strong and independent predictor of paradoxic vasoconstriction only in response to acetylcholine and cold pressor testing. Impairment of coronary blood flow increase in patients with Lp(a) levels > or = 30 mg/dl did not reach statistical significance. CONCLUSIONS: High Lp(a) levels are associated with a selective impairment of vasodilator capacity of receptor-mediated endothelial stimuli. Impaired dilator capacity of the coronary circulation associated with elevated Lp(a) levels may contribute to the pathogenesis of myocardial ischemia in response to trigger mechanisms involving receptor-mediated stimulation such as sympathetic activation.

Acetylcholine↗
PubMed1997

[Physical training of patients with sleep apnea].

PURPOSE: It is a common question of sleep apnoea patients in the sleep lab whether they stand a chance to decrease the symptoms and severity of their disease by physical exercise. As far as we know, there is no data about this specific question until now, even though this has been subject to speculation. A few studies, however, report on an improvement of the respiratory drive (and chemoreceptor sensitivity) after physical exercise in athletes. The aim of this study was to prove whether physical exercise in sleep apnoea patients could improve the symptoms of their disease in an open trial. METHODS: 11 Patients with mild to severe sleep apnoea syndrome (1 f, 10 m, mean age 53.8x) took part in a 6-month period of physical exercise twice a week 2 h each time under the instructions of physical therapists. Before and after the 6mo period a full PSG without CPAP or BIPAP, a bicycle exercise test with lactate profile, echocardiography, blood test, and body weight and body height measurement was performed. Statistical analysis was done using Wilcoxon ranked test and multiple regression analysis. RESULTS: There was no significant bodyweight reduction in all patients after the 6mo period of physical training, no significant difference in either basal SaO2 nor mean SaO2 and no significant improvement in physical status by the p at 4 mmol lactate on the lactate profile. Echocardiographic changes were not found; there was no significant change in the blood pressure profiles during the bicycle test. No cardiopulmonary problems including exercise-induced high blood pressure were reported during the training period. There was, however, a significant decrease of the RDI (p < 0.05), but no significant change in the REM-sleep % of total sleep time (TST) and the TST itself. CONCLUSIONS: There was an improvement of the sleep apnoea syndrome correlated to a decrease of the RDI in the studied patient population due to a possible increase in the respiratory drive or a stabilised muscle tone ine the upper airways after physical exercise, as reported by other authors, because weight reduction could not be the reason in our patients. Our trial showed that the exercise does not increase the severity of symptoms of sleep apnoea by changing the REM/non REM ratio or for any other reasons. A physical training programme for sleep apnoea patients as an additional treatment should therefore be considered.

Adult↗
PubMed1997

[Reducing cholesterol in cardiovascular rehabilitation--exercise versus drug therapy].

Prospective epidemiological studies have proven a close link between the improvement of the lipoprotein profile and reduction of coronary heart mortality in coronary heart disease (CHD) patients. Both, regular physical activity and pharmacological intervention are capable of improving the lipoprotein profile and may independently reduce coronary stenoses and cardiac events in CHD patients. Because of the multifactorial genesis of atherosclerosis, regular physical activity is of major importance for cardiac rehabilitation and improvements of other risk factors besides the lipoprotein profile e.g. rheology, hypercoagulability, hypertension, peripheral insulin resistance and oxidative status may be expected. The combination of life-style changes e.g. physical activity, diet and smoking cessation together with pharmacological intervention, if risk factors remain high, seems to be the best therapy for patients with CHD. A sole pharmacological intervention seems to be insufficient.

Anticholesteremic Agents↗