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Biomedical subjects

J Keul

Publications and source records attributed to J Keul.

At least 181 records · Page 10Linked to original sources
PubMed1985

[Induced platelet aggregation in patients with coronary heart disease as well as trained and untrained control persons].

Induced in vitro platelet aggregation (adrenaline and collagen) and serum lipid levels were investigated in 21 postinfarction patients, in 11 of these patients subsequent to therapy with 46 +/- 14 mg nifedipine per os daily for one week and in 21 untrained, 16 endurance-trained, and 17 non-endurance-trained healthy male control subjects. Plasma catecholamine levels at rest (patients) and oxygen uptake capacity (control subjects) were determined in subgroups. Mean platelet aggregation was increased in patients (p less than 0.05) and was decreased both in endurance-trained subjects (p less than 0.05) and in the group of 11 patients subsequent to therapy with nifedipine (p less than 0.01), but platelet aggregation was slightly higher in non-endurance-trained individuals. Adrenaline-induced platelet aggregation correlated positively with collagen-induced aggregation (r = 0.72), with LDL-cholesterol fraction (r = 0.51) and negatively with oxygen uptake capacity (r = -0.49). Patients with increased LDL-cholesterol levels also showed increased plasma catecholamine levels (r = 0.49 and r = 0.43). Low aerobic capacity (oxygen uptake capacity), high LDL-cholesterol levels and plasma catecholamine concentrations indicate an increased induced platelet sensitivity in vitro.

Adult↗
PubMed1984

[Is the alpha adrenergic receptor density increased in intact thrombocytes in non-isometric trained athletes?].

Alpha-adrenoreceptors were determined as an equivalent to 3H-dihydroergocryptine (DHE) specifically bound on intact thrombocytes in five untrained volunteers (I), eight non-staticly trained sportsmen (II), and eight intensively staticly trained athletes (III). Bmax was 933 +/- 363 (I), 982 +/- 373 (II), and 1796 +/- 539 fmol DHE X 10(-9) thrombocytes (III). KD was 1.28 +/- 0.49 (I), 2.94 +/- 1.12 (II), and 3.58 +/- 1.07 nmol X l-1 (III). The number of binding sites per cell amounted to 561 +/- 202 (I), 589 +/- 224 (II), and 1078 +/- 323 (III). The thrombocytes of the staticly trained athletes showed a significantly higher number of binding sites and a slightly higher affinity (KD) than the other groups (p less than 0.01). However, a wide range of overlapping has to be considered. The biologic significance of these results and their transferability to other organs are open at present. It is the question whether an altered adrenoreceptor density may be one factor of a higher prevalence of hypertension in staticly trained athletes on which our research group has reported recently.

Blood Platelets↗
PubMed1984

Plasma catecholamines, beta-adrenergic receptors, and isoproterenol sensitivity in endurance trained and non-endurance trained volunteers.

Six male non-endurance trained subjects (S) and six marathon runners (M) underwent graded treadmill exercise (T) and isoproterenol stimulation (I; 2 and 4 microgram X min-1). beta-adrenergic receptor density was additionally determined as the amount of 3H-Dihydroalprenolol (DHA) specifically bound on intact polymorphonuclear leucocytes. Heart rate, VO2 uptake, lactate, plasma noradrenaline, and adrenaline were estimated during T. Heart rate, stroke volume, cardiac output, as well as lactate, glucose, free fatty acids (FFA), and glycerol levels in the blood were determined during I. M showed the known training-dependent responses during T, such as lower heart rates, lactate levels, and plasma catecholamines at identical work loads, as well as higher VO2 max than S. I-induced cardiac output increase was quite similar in both groups. Stroke volume, however, increased significantly in M and stayed constant in S. Lactate decreased (S), glucose increased significantly (M), glycerol increased similarly in both groups, FFA rise was less marked in S. I-induced stroke volume response (I) may be indicative of a more economic regulation of heart work in M than S. Lactate decrease and less marked FFA increase, as observed in S, may be the result of a somewhat higher cardiac energy demand, dependent on less economic heart work. Higher DHA-binding as observed in M, as well as stroke volume response and glucose increase, may be indicators of a training-dependent rise in sensitivity to catecholamines. The unsolved question is, however, to what extent beta-receptor responses in intact blood cells are significant for receptor behavior in other organs.

Adult↗
PubMed1984

Age- and exercise-related sympathetic activity in untrained volunteers, trained athletes and patients with impaired left-ventricular contractility.

To study the influence of training, aging and left-ventricular contractility on the sympathetic nervous system, responses of plasma catecholamines and density of adrenoreceptors on intact blood cells were evaluated in 21 dynamically trained subjects, 8 statically trained weight lifters, 15 healthy young and 15 old control subjects, and 55 post-infarction patients. Plasma catecholamines are indicators of the overall sympathetic tone, while the density of adrenoreceptors is a cellular indicator of the sensitivity to catecholamines. Static and dynamic training result in lower catecholamine response at identical work loads during incremental ergometric tests. Higher density of beta 2 receptors on intact leucocytes and higher sensitivity to isoproterenol are seen in the dynamically trained test subjects. Higher density of alpha 2 receptors on intact thrombocytes is found in the weight lifters. Despite the training-dependent control of the sympathetic activity bradycardia occurs only in endurance-trained subjects, indicating an additionally increased vagal control. The exercise-related tachycardia of the weight lifters, on the other hand, points to an insufficient vagal control of the cardiac sinus rate. Decrease of physical fitness, as related to aging, a deficit in physical training and impaired left-ventricular contractility are connected with a higher sympathetic activity at identical work loads and a lower beta-receptor density on intact blood cells and, in cardiac patients, on myocardial cells as well (Bristow et al. 1982). Changes in the sympathetic system may amplify the age- and disease-dependent decrease of the cardiac function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Sympathetic activity in patients with coronary insufficiency].

Twelve healthy control subjects, 9 cardiac patients with normal central hemodynamics, 9 patients with impaired left-ventricular contractility during exercise, and 10 patients with impaired contractility and coronary insufficiency (anginal pain and ST-segment depression of ECG) were investigated. Central hemodynamic values (Swan-Ganz catheter) as well as free plasma catecholamines noradrenaline and adrenaline were simultaneously determined at rest and during incremental exercise. At rest, no significant differences were observed between all groups. The cardiac patients with normal central hemodynamics also did not show any significant differences in their plasma catecholamine responses during exercise as compared with healthy control subjects. Patients with impaired left-ventricular contractility, indicated by a significantly increased pulmonary capillary wedge pressure, as reference value of increased left ventricular end-diastolic pressure, both with negative and positive indicators of coronary insufficiency during exercise, showed significantly higher noradrenaline levels at identical work loads than control subjects. However, adrenaline responses were only significantly higher in patients with positive indicators of coronary insufficiency during exercise. The noradrenergic responses may be triggered by a borderline reduction of cardiac output as well as by increased pressures in the low-pressure system. The over-proportional adrenergic responses may be an indicator of precordial anginal pain and anxiety. This reaction is seen to be significant for a further increase in myocardial oxygen demands and anginal pain.

Coronary Disease↗
PubMed1984

[Changes in sympathetic activity in 18 postinfarct patients following a year of exercise therapy].

18 male post-infarction patients (56 +/- 9 years) were investigated before and after 1 year of controlled physical therapy. Results were compared with those observed in 7 healthy male control subjects (47 +/- 6 years). Left-ventricular impairment of the investigated patients corresponded haemodynamically to stages I and II of the Roskamm-Reindell classification, based on a Swan-Ganz catheter. The influence of physical therapy on plasma catecholamine levels was evaluated; free plasma catecholamines are seen as reference indicators of sympathetic activity. Cycling performance capacity (supine position) of the patients increased from 101 +/- 25 watt to 131 +/- 24 watt. Before and after physical therapy, maximal heart rate responses were similar (121 +/- 17 as compared with 119 +/- 16 min-1). After physical therapy, maximal noradrenaline responses were 16% lower, adrenaline responses down by 25%, and mean arterial blood pressure was 14 mm Hg lower. At identical work-load (50 watt level), reductions after physical therapy amounted to 25% (noradrenaline), 41% (adrenaline), 16% (heart rate), and 21 mm Hg (mean arterial blood pressure).

Blood Pressure↗
PubMed1984

[Incidence of hypertension in 810 male sportsmen].

Blood pressure was recorded at rest and during exercise (n = 577) in 810 male sportsmen. Larger subgroups included 125 cyclists, 98 long-distance runners, 90 cross-country skiers, 108 players of various ball games, 25 weight-lifters, and 29 swimmers. At rest, hypertension was observed in 3.8% and borderline hypertension in 7.8% of the sportsmen investigated. When blood pressure responses during exercise were also included, values were increased by 28% to 4.9% (hypertension) and by 26% to 9.8% (borderline hypertension). In the sportsmen investigated, the age range 14-29 years was overrepresented. The age-corrected prevalence was 5.4% (hypertension) and 11.1% (borderline hypertension) at rest. The prevalence of increased blood pressure in sportsmen was about half of the prevalence expected for the total population (p less than 0.05). The low incidence of hypertension in sportsmen may be due to physical training as well as to genetic factors. Increased blood pressure was significantly more frequent in swimmers and weight-lifters than in the other investigated subgroups. In these two sports, unfavorable training-specific factors may compensate for the possible beneficial effects of physical training.

Adolescent↗
PubMed1983

[Beta-adrenergic receptors and plasma catecholamine behavior in trained and untrained athletes].

6 sports students (VO2 max. 54.0 +/- 2.6 ml/kg . min) and 6 marathoners (VO2 max. 65.7 +/- 2.0 ml/kg . min) performed graded treadmill tests. Free plasma catecholamines (noradrenaline and adrenaline), heart rate, lactate were assessed at rest and during exercise. The behaviour of beta-adrenergic receptors of polymorphonuclear leukocytes was estimated additionally before the treadmill test. The maximum running velocity was 14.6 +/- 0.8 km/h (sports students) and 17.3 +/- 0.6 km/h (marathoners). Noradrenaline was approximately 46% (v = 12 km/h) to 67% (v = 14 km/h) lower in the group of marathoners than in sports students; adrenaline showed no or smaller differences between both groups. No significant differences in the plasma catecholamine behaviour occurred between the groups at rest and during maximum exercise. Specific binding of 3H-Dihydroalprenolol to intact cells was higher in the marathoners than in sports students (p greater than 0.01). Scatchard analysis revealed a maximum binding of 21.1 fmol/10(7) cells (sports students) and 35.3 fmol/10(7) cells (marathoners), which indicated approximately 1,300 (sports students) and 2,150 binding sites cell (marathoners). Inverse correlations between noradrenaline (r = -0.63), VO2max. (r = -0.79) and the specific binding of 3H-DHA were observed. The reduction of plasma catecholamines (approximately 46-67%) and the increase in specific binding sites (approximately 67%) were in the same range.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

[Behavior of free catecholamines in blood and urine of ambulance men and physicians during quick responses].

Free urine adrenaline, noradrenaline, (additional free plasma catecholamines in the physicians), and blood lactate were determined in 11 ambulance men and 5 physicians to assess stress during medical service. Stress was evaluated employing a stress index, based on difficulties in driving, traffic, severity of injuries or illness. Emergency cases with seriously injured subjects or reanimation were judged to have a 4-fold higher stress index than routine cases where strong physiological or psychological stress was absent. Urine catecholamines and stress indices were estimated in 3-h intervals. The calculations were based on the stress induced catecholamine concentrations minus the basal excretion during the same 3-h interval. Urine adrenaline and noradrenaline in ambulance men and physicians correlated directly with the stress index, as well as the plasma catecholamines of the physicians. Lactate levels showed similar behaviour and a descriptive direct correlation with the plasma catecholamines. Urine adrenaline increased more--dependent on the stress index--than urine noradrenaline. This over-proportional adrenaline response may be an indicator for the additional psychological stress in emergency cases. Therefore physicians showed--based on the same stress index--a tendency to higher urine adrenaline excretion and blood lactate levels than the ambulance men, which might be the consequence of the overall responsibility of the physicians. Because of the observed catecholamine responses during medical service, coronary insufficiency or hypertension might be contra-indications for participation in the medical service; regular clinical investigations including ergometric tests are advisable.

Adult↗
PubMed1983

[Plasma dopamine, noradrenaline and adrenaline response during cardiac and peripheral-muscular exhaustion].

Nine healthy subjects performed 2 different graded bicycle ergometric tests. The 1st test started with 50 watt and was increased 50 watt after 3 min till exhaustion as a model of a metabolic and cardiac exhaustion. The 2nd test started with 100 watt and was increased 50 watt after 15 min till exhaustion as a model of a peripheral-muscular exhaustion. The behaviour of plasma catecholamines, lactate and glucose levels, heart rate and oxygen intake was examined. The results were as following: Performance ability 305 (test 1) and 233 watt (test 2; mean values), work time 17.5 min (1) and 51 min (2), heart rate 185 min-1 (1) and 175 min-1 (2), noradrenaline 30.7 nmol/l (1) and 11.0 nmol/l (2), adrenaline 6.9 nmol/l (1) and 2 nmol/l (2), lactate 9.2 (1) and 6.6 mmol/l (2), glucose 5.6 mmol/l (1) and 4.7 mmol/l (2). During highly intensive dynamic exercise (test 1), three times higher catecholamine and 50% higher lactate responses were observed, than during peripheral-muscular limited endurance exercise (test 2). Above an exercise level of more than 30% VO2 max., nor- and adrenaline increased significantly. Below 50-70% VO2 max. steady-state-behaviour occurred. Above this range unsteady-state-behaviour of plasma catecholamines was observed. Dopamine did not show any significant time and intensity dependent increase. Noradrenaline and adrenaline followed the same initial 1st order elimination kinetic.

Adult↗
PubMed1983

Changes in HDL subfractions after a single, extended episode of physical exercise.

In order to investigate the changes in HDL subfractions induced by a single period of extended physical exercise, 9 endurance-trained adults were examined before and 6 min, 1 and 6 h after a 30 km cross-country race. In contrast to less evident changes in the concentrations of total HDL, apolipoprotein A-I and A-II, there were significant changes in HDL subfractions. Resting levels of protein and cholesterol content of the HDL subfractions 1-3 increased (subfraction 1, density gradient 1.093: 1.68 +/- 0.58 to 3.24 +/- 0.86 mmol/1 cholesterol, P less than 0.001), while the concentrations in HDL subfractions 11-12 decreased proportionately (subfraction 12, density gradient 1.142: 3.68 +/- 0.81 to 2.19 +/- 0.22 mmol/1 cholesterol, P less than 0.001). The results suggest that physical exercise induces an increased formation of HDL particles of lower density from HDL particles of higher density. It was concluded that this formation is related to the catabolism of triglyceride-rich lipoproteins in the post-exercise period.

Cholesterol↗
PubMed1983

Two-dimensional echocardiographic measurements of left ventricular volume and stroke volume of endurance-trained athletes and untrained subjects.

The left ventricular volume (EDV), the left ventricular total volume (TDV), and the stroke volume (SV) of 40 male untrained subjects and 68 endurance athletes were determined using one-dimensional echocardiography, two-dimensional echocardiography, and a combined method. The accuracy of the volume and stroke volume measurements was checked by comparing them to ergometrically determined maximum oxygen pulse (max O2-P) and to radiographic heart volume (HV). There was clear improvement in the EDV, TDV, and SV measurements when using two-dimensional echocardiography and the combined method in comparison to one-dimensional echocardiography. The best correlation to the max-O2-P was reached by TDV2 (combined method, r = 0.8738). This method includes the myocardium of the left ventricle similar to heart volume measurements. The relationship is as close as between HV and max O2-P (r = 0.8665). The method suggested here is sufficiently accurate to be used in performance diagnosis to determine the size of the left ventricular volume and to classify pathological size changes or those due to training.

Adolescent↗
PubMed1983

Correlations between laboratory testing and distance running performance in marathoners of similar performance ability.

Correlations between distance running performance and laboratory testing were examined in 11 marathoners of similar fitness (VO2max 66.4 +/- 1.7 ml/kg X min). They performed a graded treadmill test and a subsequent 30 km cross-country run. Heart rate, oxygen intake, blood lactate, and plasma catecholamines were measured during the treadmill test. Lactate equivalent, individual lactate threshold, 4 mmol lactate threshold, submaximum (16 km/h running velocity) lactate behavior, submaximum catecholamine responses, submaximum lactate-catecholamine product, measured VO2max, and extrapolated VO2max were examined for their adequacy in the evaluation of distance running capacity. Race times and free urine catecholamines were estimated in the field experiment. Direct correlations were found between race times and minimum lactate equivalent (r = 0.69), submaximum lactate levels (r = 0.52), submaximum catecholamine responses (r = 0.69), submaximum lactate-catecholamine product (r = 0.79), respectively. Inverse correlations were observed between race times and oxygen intake at individual lactate threshold (r = -0.68), 4 mmol lactate threshold (r = -0.76), measured VO2max (r = -0.71), and extrapolated VO2max (r = -0.63). Further correlations were found between submaximum noradrenaline and lactate behavior (r = 0.53), as well as between noradrenaline and adrenaline responses (r = 0.72). No significant correlation was observed between relative heart volumes or catecholamine excretion and race times.

Adult↗
PubMed1983

[Two-dimensional stress echocardiography and plasma catecholamine measurements in the evaluation of the physiologically hypertrophied heart].

Two-dimensional stress echocardiography was performed in 8 untrained subjects, 8 long-distance runners, and 8 cyclists. The ergometric investigation was performed with subjects in supine position on a bicycle ergometer with increasing work loads of 50 Watts. At each working level, lactate, norepinephrine, and epinephrine were measured. The long-distance runners and the cyclists had an equal maximum oxygen uptake when tested with treadmill or bicycle ergometer. Absolute and relative heart volumes also showed the same amount of hypertrophy. In spite of this, lactate, catecholamines, and heart rate of the long-distance runners rose earlier during the supine ergometer test. End-diastolic volume and stroke volume in the cyclists increased significantly more (delta EDV = 15%, delta SV = 32%) than in the long-distance runners (delta EDV = 1%, delta SV = 13%) and untrained subjects (delta EDV = 5%, delta SV = 9%). It is assumed that this difference in heart function is caused by diminished sympathetic activity, which is dependent on the aerobic capacity of the working muscles.

Adolescent↗
PubMed1983

[Hemodynamics, plasma catecholamine behavior and beta-adrenergic receptor density in trained and untrained subjects and cardiac insufficiency patients].

Swan-Ganz semifloating balloon-tipped catheters were introduced in 6 endurance-trained subjects, 7 untrained volunteers, 29 patients suffering from coronary heart disease, 8 patients with right heart insufficiency induced by chronic obstructive syndromes, and 8 patients with idiopathic congestive cardiomyopathy. All subjects except the patients with resting cardiac insufficiency performed graded ergometric tests during the catheter investigation. Hemodynamic values, plasma noradrenaline and adrenaline (in all subjects), and beta-adrenergic receptor density on intact polymorphonuclear leucocytes (in 6 endurance-trained subjects, 5 untrained healthy volunteers, and 6 patients with left heart insufficiency) were determined. For all subjects investigated, significant correlations were observed between resting plasma catecholamine levels and resting hemodynamic values, such as stroke volume (r = 0.47, p less than 0.001), cardiac output (r = 0.32, p less than 0.05), heart rate (r = 0.37, p less than 0.01), pulmonary vascular resistance (r = 0.52, p less than 0.001), and total vascular resistance (r = 0.40, p less than 0.01). An inverse relationship existed between the resting catecholamine levels and the performance ability. Catecholamine levels were approximately three- to fourfold higher and the beta-adrenergic receptor density approximately two- to threefold lower in patients with left heart insufficiency than in healthy untrained subjects. The plasma catecholamine levels were lower and the beta-adrenergic receptor density approximately 60% greater in trained subjects. The beta-adrenergic receptor density may be a critical dynamic parameter for the modulation of sympathetic effects.

Adult↗