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Biomedical subjects

J Keul

Publications and source records attributed to J Keul.

At least 199 records · Page 11Linked to original sources
PubMed1983

[Determination of beta-receptors on intact polymorphonuclear leukocytes in autologous plasma].

The binding of tritium labelled radioligand dihydroalprenolol was investigated on live polymorphonuclear leukocytes of 6 endurance trained (VO2 max. 65.7 +/- 2.0 ml/kg . min), and 9 non-endurance trained subjects (VO2 max. 52.0 +/- 4.0 ml/kg . min). The specific binding of dihydroalprenolol is seen as an indicator of the beta-receptor density. The specific binding of dihydroalprenolol is defined as the difference between the total binding and that amount of dihydroalprenolol that could not be displaced. The leukocytes were reincubated for the binding studies in their autologous plasma. The specific binding of dihydroalprenolol on live polymorphonuclear leukocytes shows a levelling off behaviour at a concentration of approximately 2 nmol/l dihydroalprenolol in trained as well as in untrained subjects. The specific binding amounts to about 85% (0.1 nmol/l dihydroalprenolol) to 51% (2.0 nmol/l dihydroalprenolol) of the total binding. Based on Scatchard analysis, Bmax was determined as 41.2 fmol/10(7) cells (trained subjects) and 21.6 fmol/10(7) cells (untrained subjects). KD is 0.44 nmol/l dihydroalprenolol (untrained subjects), and 0.49 nmol/l dihydroalprenolol (trained subjects). The beta-adrenergic binding sites are approximately 1300 (untrained subjects), and 2500 binding sites/cell (trained subjects). The specific binding of dihydroalprenolol on live polymorphonuclear leukocytes is significantly higher in trained than in untrained subjects. This training dependent change in beta-receptor density may be an indicator of an increased sensitivity to catecholamines.

Alprenolol↗
PubMed1983

[Simultaneous determination of hemodynamics and plasma catecholamines in trained and untrained subjects and patients with contraction disorders of the heart during rest and physical activity].

6 trained (TS) and 7 untrained (US) subjects and 16 patients (P) with left ventricular dysfunction were investigated by means of a Swan-Ganz floating catheter during graded bicycle ergometry in a supine position. 9 P suffered from a myocardial infarction and 10 were known to be hypertensive; 10 suffered from acute coronary insufficiency during exercise. Hemodynamic values, free plasma catecholamines, and heart volume at rest were determined in all cases. The relative heart volume was increased training-dependent in the TS as compared with US and P. In TS stroke volume increased more than in US, whereas in P a heart-rate-dependent adaptation of cardiac output was observed during exercise. In P cardiac output was slightly reduced during exercise and the arteriovenous oxygen difference augmented. Systolic and diastolic pulmonary artery pressure, pulmonary wedge pressure, and peripheral diastolic arterial pressure rose more in P during exercise than in TS and US. TS showed reduced, whereas P showed increased levels of circulating free plasma catecholamines (norepinephrine and epinephrine). Training-dependent changes in hemodynamic values and catecholamine levels were seen as an economic adaptation of the heart to physical stress, and the results in the patients were interpreted as indicating an uneconomic stress adaptation. In patients with disturbed left ventricular function, extracardiac compensatory mechanisms such as enhanced sympathetic activity and increased arteriovenous oxygen difference are necessary for the adaptation to physical stress.

Arrhythmias, Cardiac↗
PubMed1983

[Ventricle function in low-dose digitoxin in patients with chronic heart failure (stage II/III)].

Using one- and two-dimensional echocardiographic parameters, left ventricular function and dimensions were investigated in 11 patients with chronic heart failure (NYHA stages II-III) and in 10 normal subjects after administration of low-dose digitoxin (0.07 mg). Tests were performed before the begin of therapy, on the 3rd day following rapid saturation, and on the 15th day under maintenance therapy. There was no significant decrease either of heart volume as assessed by X-ray or of enddiastolic volume measured echocardiographically. However--predominantly in patients--a marked decrease in endsystolic diameter (p less than 0.01) and an increase in posterior wall motion amplitude (p less than 0.05) was observed resulting in increased stroke volume, shortening fraction (p less than 0.001). Early diastolic left ventricular filling speed also increased significantly in both groups (p less than 0.01). Changes in these parameters were more pronounced in patients than in normal subjects. In both groups the effects were achieved soon after rapid saturation, increasing slightly during the period of chronic administration of low-dose digitoxin. Parallel to the changes in echocardiographic parameters, a noticeable clinical improvement occurred among patients. No side effects were observed as serum digitoxin levels were in the therapeutic range. It may be concluded that low-dose digitoxin can be employed to increase cardiac contractility in patients with heart failure.

Adult↗
PubMed1983

[Sensitivity of free and conjugated plasma catecholamines as indicators of left ventricular contraction disorder of the heart].

Hemodynamic parameters were measured (using a Swan-Ganz semifloating balloon-tipped catheter) and free and conjugated catecholamines were assessed radioenzymatically in plasma from the pulmonary artery in 6 patients (5 postinfarction patients, 1 with idiopathic congestive cardiomyopathy; 56 +/- 7 years old) and 6 healthy control subjects (48 +/- 6 years old). The tests were carried out at rest and during bicycle ergometry in the supine position at incremented work loads. Neither at rest nor during exercise was cardiac output in patients and controls significantly different. The mean capillary wedge pressure (PCPm) was elevated above control values in 1 patient at rest and in all patients during exercise. This may be indicative of impaired left ventricular contractility. The mean ergometric exercise level in patients was 100 w, in the control group 187 w. Conjugated plasma catecholamines showed no exercise dependency, and there were no significant differences between patients and controls. Free dopamine comprised less than 5% of the whole dopamine fraction, free noradrenaline and free adrenaline less than 50% of their fractions. A significant exercise dependency was observed in the case of free noradrenaline and adrenaline in patients and controls; at the same exercise levels, the increase in free noradrenaline was significantly higher in patients than in control subjects (p less than 0.01). During exercise, a correlation between free plasma noradrenaline and PCPm (r = 0.60, p less than 0.01) was observed, but not with certainty in patients (r = 0.27). The free plasma noradrenaline may be seen as a sensitive sympathetic indicator of impaired left ventricular contractility.

Adult↗
PubMed1982

[Catecholamine excretion during physical exercise and mental performance].

The basal and exercise-induced heart rates, lactate levels, and the adrenaline and noradrenaline excretions in the urine were measured during different types of physical exercise and mental performance: during moderate physical exercise (Ia, n = 12), submaximal physical exercise (Ib, n = 24), during moderate mental performance (motorway driving, IIa and IIb, n = 25), higher-grade mental performance (driving car-simulator, III, n = 14), and during submaximal mental performance (car racing, IV, n = 48). The moderate physical exercise and moderate mental performance could not be differentiated from one another, or from the higher-grade mental performance using the above-mentioned parameters. Both the submaximal physical exercise and mental performance resulted in a comparable lactate acidosis, heart rate increase, and noradrenaline excretion; the excretion of adrenaline is, however, 3 times higher after submaximal mental performance, than after submaximal physical exercise. The ratio of adrenaline to noradrenaline excretion changed from approximately 1:4 (during physical exercise and moderate mental performance) to approximately 1:2 during submaximal mental performance. The excretion of adrenaline and the ratio of adrenaline to noradrenaline excretion can therefore be used to differentiate between higher-grade mental performance and physical exercise. These parameters can be easily measured without discomfort to the subjects.

Acidosis↗
PubMed1982

[Catecholamines, Cardiocirculatory, and Metabolic Response During Graduated and Continuously Increasing Exercise].

Adrenaline, noradrenaline, glucose, glycerol and the free fatty acids (FFA) in the blood, as well as the heart rate and oxygen intake, were tested in six healthy male volunteers (age: 28 +/- 6 years) during graduated (I) and continuously (II) increasing bicycle ergometric exercise (upright body position). The maximum heart rate, the VO2 max, the maximum lactate and FFA concentration show no significant difference, whereas adrenaline, noradrenaline and the glucose levels are significantly lower, and the glycerol concentration is slightly higher during the maximum test II as compared with test I. At some submaximum exercise levels, the lactate concentration and the heart rate are slightly lower, adrenaline and noradrenaline are significantly lower during test II; the FFA, glycerol and the oxygen intake do not show any significant difference. The duration of exercise was similar in both tests. The total work was about 50% lower in test II, and the maximum performance was slightly higher as compared with test I. These results could have significance for the planning of working conditions, the rehabilitation of patients, and the organisation of training for athletes.

Adult↗
PubMed1982

[Effect of selective and non-selective adrenoceptor blockade during physical work on energy metabolism and sympatho-adrenergic system (author's transl)].

The influence of an acute beta-adrenoceptor blockade on work capacity, oxygen intake, plasma catecholamines, and on energy metabolism was investigated in 9 healthy subjects during graduated ergometric exercise. The examinations were carried out after p.o. administration of 10 mg bunitrolol (BU), methypranol (ME) and placebo in random sequence. The exercise capacity shows a 15% decrease after both beta-blockers; heart rate shows a maximum 20% (BU) and 25% (ME) reduction, respectively. On account of the greater sympathetic intrinsic activity BU does not influence the resting heart rate, in contrast to ME (-8%; p greater than 0.05). BU leads to a decrease of the catecholamine levels (with low sympathetic tone), which is assumed to be caused by an effect on presynaptic receptors. At the same submaximum exercise levels plasma catecholamines are higher after BU and ME than after placebo; however, the maximum levels are not reached with placebo. In relation to the relative oxygen intake, which is inhibited by 4-6% by BU and ME (p greater than 0.05), the differences of the catecholamines decrease in performance caused by beta-blockade. BU does not show an influence on lactate, glucose, free fatty acids, and glycerin and thus represents a more selective blockade. ME inhibits lipolysis (measured by the glycerin level) by a maximum of approx. 50%. Lactate level increase is approx. 30% lower with ME. Glucose level decrease is approx. 20% higher with ME than with placebo.

Adrenergic beta-Antagonists↗
PubMed1982

[Plasma catecholamines and hemodynamics in patients with heart failure (author's transl)].

Plasma catecholamines and hemodynamic were assessed in 32 patients with heart failure of varying degrees due to coronary artery disease as well as in twelve healthy control subjects. The studies employed the use of a (Swan-Ganz) semi-floating, balloon-tipped, thermodilution catheter during supine bicycle ergometry at incremented workloads (except in four patients with overt symptoms at heart failure at rest). As compared with control subjects, the patients showed increases in radiologically-determined cardiac volumes, right atrial, right ventricular, pulmonary artery and pulmonary capillary wedge pressures proportionately expressing increasing degrees of severity and, accordingly, decreasing values of cardiac output and stroke volume as well as a severity-dependent tendency to increasingly rapid heart rates. Similarly, as compared with control subjects, catecholamine concentrations increased in proportion with the pathologic elevation of pressures and inversely proportional to the cardiac output. With respect to a given catecholamine concentration, the patients showed a severity-dependent decrease in cardiac output, as an expression of the degree of functional myocardial impairment, as well as a lower heart rate and higher total peripheral resistance (at the same catecholamine level). The heart rate reduction at the same catecholamine concentration may be due to a reduced adrenergic receptor sensitivity.

Blood Pressure↗
PubMed1981

[Plasma catecholamines, metabolic substrates, aerobic and anaerobic capacity during exercise in supine and sitting position (author's transl)].

The influence of a graduated bicycle ergometric test in supine and sitting position on the work capacity, the plasma catecholamines, the carbohydrate (glucose and lactate) and lipid metabolism (free fatty acids and glycerol) and the heart rate and oxygen intake was examined in six healthy subjects. The work capacity is approx. 30% higher in sitting position. In supine position, adrenaline and nor-adrenaline are lower at rest, at all submaximum levels and during maximum ergometric exercise. Glucose, free fatty acids and glycerol show no differences dependent on the body position at the same submaximum levels, only the lactate level is approx. 30% higher (200 Watt) in supine position. During maximum graduated exercise in sitting position the glucose level is 10% higher than in supine position, the free fatty acids show no difference; the lactate level is approx. 37% higher, the glycerol level approx. 40% than in supine position. The heart rate and the oxygen intake don't show any position dependent differences at rest and at the same submaximum levels. During maximum ergometric exercise they are 15% (heart rate) and about 30% (oxygen intake) higher than in supine position, corresponding to a higher exercise level.

Adult↗
PubMed1981

[Plasma catecholamines, metabolic substrates, aerobic and anaerobic capacity during graduated treadmill and bicycle ergometer exercise (author's transl)].

Adrenaline, noradrenaline, glucose, lactate, free fatty acids, and glycerine in blood, as well as heart frequency and oxygen intake were examined in 6 healthy male subjects (28 +/- 2.6 years) before, during and after a graduated treadmill (TME) and bicycle ergometer (BE) test. Adrenaline, noradrenaline, the energy supplying substrates, and the oxygen-intake show no differences during TME and BE at given submaximal levels. Noradrenaline is 27% (0.10 less than p less than 0.05) higher, pulse rate is 6% (p less than 0.05) lower, oxygen intake 4% (greater than 0.05) lower, and the glycerine level 25% (0.10 less than p less than 0.05) lower during maximal BE exercise. The tendency toward a higher noradrenaline release during BE exercise can be influenced by a greater static-pressure stress opposed to a dynamic-circulatory stress during TME testing. An increased alphareceptor stimulation leads to a negative chronotropic effect, whose cause is assumed to be a baroreceptor stimulation. The TME induces a higher circulation and a more economic oxygen supplying of the muscles exercised, as well as a favourable fat oxidation, which is recognizable by a more rapid increase of glycerine (0.10 less than p less than 0.05). When referring to exercise acidification (a tendency toward a lower lactate production during submaximal TME testing shows here), oxygen intake capability, energy supplying substrates, and the catecholamines, both forms of ergometer testing are comparable one to another; a falsification appears only when plasma catecholamines and lactate levels are based on the heart frequency, as it is influenced by the form of exercise.

Adult↗