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Biomedical subjects

M Halle

Publications and source records attributed to M Halle.

At least 19 recordsLinked to original sources
PubMed2006

[Blood pressure lowering through physical training--what can be achieved?].

In the meantime, the positive effect of physical training, both in primary and secondary prevention of hypertension, has been confirmed in numerous studies. In recent years, it has been shown that regular sports activity of moderate intensity suffices to bring about a lowering of blood pressure. Highly recommended forms of training include walking, jogging, cycling and dynamic power training. Over a period of three to four months,a gradual increase in activity--for example, a daily training period of 15 to 20 minutes--should be the aim. However, an intensification of general physical activities may also lower blood pressure, irrespective of other risk factors.

Adult↗
PubMed2006

[FIFA World Cup 2006--healthcare services].

The medical services available to official participants in the FIFA World Championship 2006 will be provided by the FIFA itself, or its Organization Committee for Germany. For the first time, FIFA requires comprehensive screening examinations for the players, and this will be a prerequisite for participation in the tournament. The structures for the provision of medical care during the World Championship tournament are described taking the plans for the Munich venue as an example.

Echocardiography↗
PubMed2006

[Sudden cardiac death in sports].

Sudden cardiac death in persons actively practicing in sports is usually due to cardiovascular disease. In athletes younger than 35 years, the most common diagnosis is hypertrophy of the left ventricle, an anomaly of the coronary arteries, acute myocarditis, or right-ventricular dysplasia. 80% of older athletes are found to have coronary heart disease. For those actively engaged in serious sports activities, such examinations as ECG, exercise ECG and echocardiogra phy are essential elements of medical screening. In the case of leisure sports activities, the German Society for Sports Medicine and Prevention recommend that a medical check be done before a person starts to seriously practice sport, with the aim of identifying cardiovascular factors or anomalies.

Acute Disease↗
PubMed2006

[World Football Championship 2006--anti-doping regulations].

On the basis of the current anti-doping requirements for the World Cup, major processes and regulations are explained. Over and beyond the area of football, they are highly relevant for physicians responsible for the care and treatment of professional athletes. Apart from a knowledge of the respective current anti-doping list of banned substances, the administrative guidelines for the application to use notifiable substances must be complied with. In order to avoid errors resulting in serious consequences for athletes, the care-providing physician in professional sport must have immediate access to the necessary information on anti-doping regulations, and be familiar with the contact addresses of the respective anti-doping authorities.

Adrenergic beta-Agonists↗
PubMed2003

Cardiorespiratory fitness modifies the association between dietary fat intake and plasma fatty acids.

OBJECTIVES: To investigate the relation between (1) cardiorespiratory fitness and plasma saturated, monounsaturated and polyunsaturated fatty acids and (2) the interactions between cardiorespiratory fitness, dietary fat intake and plasma fatty acid composition. DESIGN: Cross-sectional analysis. SETTING AND SUBJECTS: The subjects were randomly selected, 127 middle-aged Finnish men participating in the DNASCO exercise intervention study. INTERVENTIONS: Cardiorespiratory fitness was determined spiroergometrically, dietary intake of macro- and micronutrients by 4-day food records and plasma fatty acids by gas chromatography. The subjects were divided into tertiles of aerobic fitness. RESULTS: Differences between fitness tertiles were not observed for dietary intake of total fat, and saturated, monounsaturated or polyunsaturated fatty acids (percent of total energy). In contrast, plasma saturated fatty acids were significantly lower (P <0.01) and polyunsaturated fatty acids significantly higher (P <0.05) in the highest fitness tertile compared to the lowest tertile. Dietary saturated fat intake was positively associated with plasma saturated fatty acids (r=0.342; P <0.05) and inversely with plasma polyunsaturated fatty acids (r=-0.453; P <0.01) only in the lowest fitness tertile. In addition, a positive correlation between body mass index and plasma saturated fatty acids (r=0.516; P <0.01) as well as a negative correlation between body mass index and plasma polyunsaturated fatty acids (r=-0.516; P <0.01) was observed in the lowest tertile solely. CONCLUSION: Different levels in cardiorespiratory fitness are associated with different levels in plasma saturated and polyunsaturated fatty acids and lead to modifications in the association between dietary and plasma fatty acids. These findings can perhaps be explained by a reduced hepatic fatty acid and lipoprotein synthesis as well as by an enhanced muscular lipid utilization, which are commonly seen in those who are physically active and who exhibit a higher level of fitness.

Chromatography, Gas↗
PubMed2001

Cardiovascular, metabolic, and hormonal parameters in professional tennis players.

During the past decade, the physical and mental stress in professional tennis has been constantly increasing. The overall intensity in tennis ranges between 60 and 70% of maximum oxygen uptake and the energy requirements are mainly provided by aerobic energy metabolism. Therefore, particularly with respect to the duration of the tournaments and the length of the matches, a good aerobic capacity promotes continuous success in professional tennis. During frequent periods of high intensity, however, muscular energy is derived from anaerobic glycolysis. Therefore, sports-specific conditioning programs in tennis should improve both glycolytic and oxidative muscular metabolism. Years of training and competition induce a number of cardiovascular and metabolic adaptations: an increase in heart size in terms of an athlete's heart, higher oxygen uptake capacity, improved muscular oxidative enzyme activities, reduced baseline catecholamine levels, and a lower resting heart rate. In addition, tennis induces side-specific increments in bone density, bone diameter, and bone length of the upper extremity. Furthermore, structural and functional adaptations of the conducting arteries in the preferred arm could be demonstrated in professional tennis players. In conclusion, tennis is a very complex sport involving strength, power, speed, agility and explosiveness, as well as endurance components. Scientific data on exercise-related cardiovascular and metabolic parameters in professional tennis are important to evaluate the players individual fitness level and will help to improve sports-specific conditioning programs. This in turn will not only enhance performance but also prevent overstrain and burnout syndromes.

Adaptation, Physiological↗
PubMed2000

Fast re-rendering of volume and surface graphics by depth, color, and opacity buffering.

A method for quickly re-rendering volume data consisting of several distinct materials and intermixed with moving geometry is presented. The technique works by storing depth, color and opacity information, to a given approximation, which facilitates accelerated rendering of fixed views at moderate storage overhead without re-scanning the entire volume. Storage information in the ray direction (what we have called super-r depth buffering), allows rapid transparency and color changes of materials, position changes of sub-objects, dealing explicitly with regions of overlap, and the intermixing or separately rendered geometry. The rendering quality can be traded-off against the relative storage cost and we present an empirical analysis of output error together with typical figures for its storage complexity. The method has been applied to the visualization of medical image data for surgical planning and guidance, and presented results include typical clinical data. We discuss the implications of our method for haptic (or tactile) rendering systems, such as for surgical simulation, and present preliminary results of rendering polygonal objects in the volume rendered scene.

Algorithms↗
PubMed2000

Lipoproteins and free plasma catecholamines in spinal cord injured men with different injury levels.

Persons with spinal cord injury (SCI) are especially prone to atherogenesis. This is partly explained by an unfavourable lipoprotein profile in these individuals. The impairment of the sympathetic nervous system, and the fact that SCI subjects are subject to extreme physical inactivity, may have an influence on their lipid profile and lipoprotein(a) concentration. We made a detailed investigation of the lipid profile as well as serum levels of adrenaline and noradrenaline in 80 men with SCI ranging from tetraplegia to low paraplegia and in 16 control subjects. The lipid profile of tetraplegics was characterized by elevated very low-density lipoprotein cholesterol and triglyceride levels and reduced high-density lipoprotein levels. In contrast, paraplegics had significantly higher low-density lipoprotein and total cholesterol levels. Tetraplegics had lower and the low-lesion paraplegics had higher adrenaline and noradrenaline levels than the high-lesion paraplegics and the control subjects. High-lesion SCI subjects also showed an extreme reduction in VO2max. The lipoprotein profile was dependent on the injury level and serum catecholamine concentrations. The lower the noradrenaline values, the lower the high-density lipoprotein cholesterol. The low-density lipoprotein also correlated to catecholamines and particularly adrenaline values. Despite the correlation between lipoprotein(a) and adrenaline, no significant differences in lipoprotein(a) were found within SCI individuals as well as between SCI individuals and control subjects, indicating the predominantly genetic determination of lipoprotein(a) and thus the cardiovascular risk. Different serum catecholamine levels due to impairment of sympathetic nervous system and VO2max levels were observed in SCI subjects. This was associated with a higher lipid risk profile for cardiovascular diseases; however, the risk profile is dependent on the lesion level.

Adult↗
PubMed1999

Hemostatic factors in hypertriglyceridemic men: effects of a fatty meal before and after triglyceride-lowering treatment with etofibrate.

The aims of this double-blind study were to examine whether in hypertriglyceridemic men the ingestion of a standardized fatty meal alters hemostasis negatively and whether triglyceride-lowering treatment with etofibrate for 6 weeks alters fasting and postprandial hemostasis positively, thus reversing the potential negative effects of a fatty meal on postprandial hemostasis. To answer these questions, we measured markers of hemostasis immediately before a standardized fatty meal, and 4, 6, 8, and 10 hours after the meal in 21 hypertriglyceridemic men both before and after treatment with etofibrate. We found that the concentration of plasmin alpha2antiplasmin complex markedly increased for at least 10 hours after the fatty meal, but that the activation of factor XII and the concentration of prothrombin activation fragment1+2 decreased after the fatty meal. These results on factor XII contradict reported in vitro data. Triglyceride-lowering treatment with etofibrate in 10 of these men for 6 weeks increased fasting and postprandial protein C and plasminogen and also slightly decreased the activation of fXII; however, it did not reverse the postprandial increase of PAP or change the decrease of prothrombin activation fragment1+2. Our findings indicate that postprandial lipoproteins alter markers of hemostasis positively in an antithrombotic and profibrinolytic direction. In addition, triglyceride-lowering treatment with etofibrate only slightly improves markers of fasting and postprandial hemostasis in an antithrombotic and profibrinolytic direction.

Clofibric Acid↗
PubMed1999

AnatomyBrowser: A novel approach to visualization and integration of medical information.

In this article, we present a novel technique for visualization of three-dimensional (3D) surface models, as well as its implementation in a system called AnatomyBrowser. Using our approach, visualization of 3D surface models is performed in two separate steps: a pre-rendering step, in which the models are rendered and saved in a special format, and an actual display step, in which the final result of rendering is generated using information from the prerendering step. Whereas prerendering requires high-end graphics hardware, the final image generation and display can be implemented efficiently in software. Moreover, our current implementation of AnatomyBrowser interface uses the Java programming language and can therefore be readily run on a wide range of systems, including low-end computers with no special graphics hardware. In addition to visualization of 3D models and 2D slices, AnatomyBrowser provides a rich set of annotation and cross-referencing capabilities. We demonstrate several possible applications for AnatomyBrowser, including interactive anatomy atlases, surgery planning, and assistance in segmentation.

Anatomy↗
PubMed1999

QT dispersion in exercise-induced myocardial hypertrophy.

BACKGROUND: The measurement of QT dispersion in the surface electrocardiogram is a noninvasive method used for assessing inhomogeneity of myocardial repolarization. Elevated QT dispersion is found in myocardial disease and is associated with an increased incidence of arrhythmic events. QT dispersion is also increased in myocardial hypertrophy secondary to systemic hypertension. However, the relation between left ventricular (LV) enlargement in endurance trained subjects and QT dispersion is unknown. METHODS AND RESULTS: In this study, LV mass (2-dimensional echocardiography) and QT dispersion (12-lead resting electrocardiogram) were assessed in 26 normotensive endurance trained subjects and 26 matched, less trained control subjects. Endurance trained subjects had a significantly greater LV mass (216 +/- 39 g vs 155 +/- 30 g, P <.001) but lower heart rate-corrected QTc dispersion (42 +/- 13 ms vs 51 +/- 15 ms, P =.012) than less trained control subjects. When all individuals were included, LV mass was inversely correlated with QT dispersion (r = -0.38; P =.002) and heart rate-corrected QTc dispersion (r = -0.53, P <.0001). CONCLUSIONS: These data show that myocardial hypertrophy induced by exercise training is not associated with increased QT dispersion as observed in systemic hypertension. The reduced QT dispersion reflects homogeneous myocardial repolarization and may help to explain the reduced mortality rate in regularly exercising subjects. If confirmed in further studies, the measurement of QT dispersion could provide a simple and inexpensive screening method for differentiating between physiologic and pathologic myocardial hypertrophy.

Adolescent↗
PubMed1999

Influence of mild to moderately elevated triglycerides on low density lipoprotein subfraction concentration and composition in healthy men with low high density lipoprotein cholesterol levels.

Epidemiologic studies have shown that a dyslipoproteinemia with low concentrations of high density lipoprotein (HDL) cholesterol and elevated serum triglycerides (TG) is associated with a particularly high incidence of coronary artery disease. This lipid profile is associated with increased concentrations of small, dense low density lipoprotein (LDL) particles. To evaluate the role of mild to moderately elevated TG on the LDL subfraction profile in patients with low HDL cholesterol, concentration and composition of six LDL subfractions was determined by density gradient ultracentrifugation in 41 healthy men (31+/-9 years, body mass index (BMI) 25.1+/-3.9 kg/m2) with equally low HDL cholesterol levels < 0.91 mmol/l but different TG levels: TG < 1.13 mmol/l, n = 16; TG = 1.13-2.26 mmol/l, n = 13: TG = 2.26-3.39 mmol/l, n = 12. Those men with moderately elevated TG levels between 2.26 and 3.39 mmol/l had significantly higher concentrations of very low density lipoprotein (VLDL), intermediate low density lipoprotein (IDL), and small, dense LDL apoB and cholesterol than men with TG < 1.13 mmol/l. With increasing serum TG, the TG content per particle also increased in VLDL, IDL as well as total LDL particles while the cholesterol and phospholipid (PL) content decreased in VLDL and IDL, but not in LDL particles. LDL subfraction analysis revealed that only large, more buoyant LDL particles (d < 1.044 g/ml) but not the smaller, more dense LDL, were enriched in TG. Small, dense LDL particles were depleted of free cholesterol (FC) and PL. This study has shown that in men with low HDL cholesterol levels mild to moderately elevated serum TG strongly suggest the presence of other metabolic cardiovascular risk factors and in particular of a more atherogenic LDL subfraction profile of increased concentration of small, dense LDL particles that are depleted in surface lipids.

Adult↗
PubMed1999

Influence of 4 weeks' intervention by exercise and diet on low-density lipoprotein subfractions in obese men with type 2 diabetes.

Insulin resistance is associated with dyslipoproteinemia characterized by increased serum triglycerides, reduced high-density lipoprotein 2 (HDL2) cholesterol, and increased small, dense low-density lipoprotein (LDL) subfraction particles. Physical activity and weight reduction are known to improve insulin resistance and dyslipoproteinemia, but their influence on LDL subfractions in diabetic patients is unknown. Therefore, we investigated the effect of a 4-week intervention program of exercise (2,200 kcal/wk) and diet (1,000 kcal/d: 50% carbohydrate, 25% protein, and 25% fat; polyunsaturated/saturated fat ratio, 1.0) on glycemic control and HDL and LDL subfractions in 34 obese patients with non-insulin-dependent diabetes (age, 49 +/- 9 years; body mass index [BMI], 33.1 +/- 5.1 kg/m2). Reductions in body weight (P < .001) and improvements in fasting blood glucose, insulin, fructosamine (P < .001), and free fatty acids (P < .01) by intervention were associated with reductions in serum cholesterol and apolipoprotein B (apo B) concentrations in very-low-density lipoprotein (VLDL) (P < .01), intermediate-density lipoprotein (IDL), and small, dense (>1.040 g/mL) LDL particles (P < .001). These data underlie the positive influence of weight reduction induced by exercise and diet on insulin resistance and lipoprotein metabolism in obese diabetic patients, particularly showing improvements of the LDL subfraction profile with a decrease of small, dense LDL particles. This is of particular importance, as these particles have been shown to be associated with coronary artery disease.

Adult↗
PubMed1999

Association of physical fitness with LDL and HDL subfractions in young healthy men.

A dyslipoproteinemia of increased concentrations of small, dense LDL particles and reduced HDL2 cholesterol has shown to be associated with coronary heart disease (CHD). In contrast, an increase in physical fitness and a reduction of body mass index (BMI) improve the lipoprotein profile and reduce the incidence of cardiovascular events. The association of physical exercise, physical fitness, and body weight with an atherogenic lipoprotein subfraction profile has been investigated before in obese subjects, but the relationship is unknown in a healthy non-obese population without insulin resistance or CHD. Therefore, a detailed lipoprotein subfraction profile of 3 HDL and 6 LDL subfractions was determined in 125 healthy men (26+/-5 years). Physical fitness (maximal oxygen consumption, VO2max) was assessed by ergometry and physical activity by questionnaire. Those men with the lowest physical fitness (VO2max < 40 ml/kg/min) and the lowest physical activity score had a significantly less favourable lipoprotein subfraction profile of increased concentration of small, dense LDL particles (d: > 1.044 g/ml) and reduced HDL2a cholesterol than those with a VO2max >50 ml/kg/min. Multivariate regression analysis revealed that concentrations of small, dense LDL particles were primarily determined by BMI whereas HDL2a cholesterol and apolipoprotein A-I were primarily determined by physical fitness. These findings underline the relationship between a good physical fitness, a low body weight, and a favourable lipoprotein subfraction profile even in a healthy young male population.

Adult↗
PubMed1999

Concurrent reductions of serum leptin and lipids during weight loss in obese men with type II diabetes.

The aim of the study was to examine the effects of weight reduction by exercise and diet on metabolic control in obese subjects with insulin resistance, particularly investigating if changes in serum leptin concentrations were directly associated with improvements in metabolic control. Twenty obese men (48 +/- 8 yr; body mass index 32. 1 +/- 3.9 kg/m(2)) with previously diagnosed type II diabetes mellitus were assigned to a 4-wk intervention program of exercise (2, 200 kcal/wk) and diet (1,000 kcal/day; 50% carbohydrates, 25% protein, 25% fat; polyunsaturated-to-saturated fatty acid ratio 1.0). Intervention induced significant reductions in body weight and serum leptin levels, and improvements in lipoprotein profile and glucose control. Reductions in leptin levels were directly associated with reductions in serum triglycerides and cholesterol, a finding that was independent of improvements in glucose control. These data show that serum leptin concentrations can be reduced with caloric restriction and exercise in male patients with type II diabetes, and they suggest a direct relationship between leptin and lipoprotein metabolism that is not solely due to weight reduction.

Adult↗