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Biomedical subjects

J Keul

Publications and source records attributed to J Keul.

At least 145 records · Page 8Linked to original sources
PubMed1988

Sympatho-vagal changes induced by physical training in cardiac patients.

Heart-rate and blood pressure increase correlate proportionally to myocardial oxygen consumption. A 100% increase in stroke volume, however, is related to only a 10% increase in myocardial oxygen consumption (Sarnoff et al., 1958). An economical cardiac adaptation to exercise which results in a saving of myocardial oxygen requirements (Heiss et al., 1979) is therefore based on an increased stroke volume in relation to a moderate heart-rate response and a decrease in circulatory resistance, respectively. Such a cardiac adaptation to exercise can be observed in endurance-trained subjects, dependent on a reduction in sympathetic activity and an increase in vagal tone. This favourable change in sympatho-vagal tone can be expected in all subjects undergoing physical training (endurance training) and in part also in some cardiac patients subsequent to physical therapy. However, only an approximate normalization of impaired autonomic function can be observed as a result of physical therapy in patients with significantly reduced exercise capacity, and this in less than 50% of the investigated cardiac patients. In cardiac patients with normal exercise capacity and approximately normal or slightly decreased left ventricular function, a favourable improvement in autonomic function and an increase in exercise capacity can be expected in about 50% of cases. The possibility or the extent to which the prognosis of cardiac disease is affected by the change in autonomic function remains unclear, however.

Coronary Disease↗
PubMed1988

[The effect of temazepam on the functional capacity and metabolic and cardiocirculatory parameters in consideration of the "jet lag" syndrome].

In a double-blind placebo controlled study, 14 male healthy volunteers were examined the morning after they had received an evening dose of 20 mg temazepam (Planum) with regard to functional capacity, cardial, cardiovascular and respiratory regulation as well as neuromuscular excitability and metabolic changes. After being exposed to the bicycle ergometer load, oxygen uptake, carbon dioxide output, glucose and lactate concentration were determined; furthermore the neuromuscular excitability of the musculus vastus medialis, musculus rectus femoris and musculus quadrizeps femoris was estimated. Despite unimportant capacity reductions (p greater than 0.05) concerning the maximum capacity (2.2%) as well as the maximum oxygen uptake (4.3%) under treatment with temazepam, there could not be proved any significant changes regarding cardiopulmonary and metabolic functions. On eastern and western flights, top athletes showed a very fast adaptation to the day-night rhythm without hang-over.

Adult↗
PubMed1988

[Follow-up study of 48 athletes with stage I hypertension with and without pharmacotherapy].

We found in an earlier investigation that the frequency of hypertension is considerably lower among male athletes than in a random sample of the general population. The cases of hypertension in younger athletes are primarily hypertension stage I (WHO). We followed up on the question of the course of hypertension stage I and the possibility of spontaneous remission. For this, we observed 28 nonmedicated patients with hypertension stage I for 4.2 +/- 2.3 years, 20 patients undergoing drug therapy for 2.5 +/- 1.3 years, and 12 healthy athletes for 4.2 +/- 2.2 years. Under drug therapy, as expected, there was a normalization of both basic and exercise blood pressures. Fifty percent of patients without drug therapy showed remission of the elevated basic and exercise pressures after 2 to 3 years; 50% had an unchanged high pressure or deterioration. The transition of hypertension WHO stage I to stage II with regard to left ventricular hypertrophy could be ruled out echocardiographically in patients with a favorable course (remission). However, there was a tendency in this direction among patients with the least favorable course.

Adrenergic beta-Antagonists↗
PubMed1988

[Behavior of heart rate, blood pressure, lactate, glucose, noradrenaline and adrenaline level in coronary heart disease patients in the course of light swimming stress].

In previous investigations, we have been able to demonstrate that healthy individuals and CHD patients with normal exercise capacity experience changes in cardiovascular parameters, metabolism and sympathetic activity during light swimming exercise, changes which are not observed in seated bicycle ergometry at an exercise level of less than 2 W/kg-1. We have now examined 12 post-infarction patients (54.3 +/- 6 years) with limited exercise capacity (1.2 +/- 0.3 W/kg-1), who have been participating in physical therapy for 29 months (median time) under continuous medication. The examination comprised incremental seated bicycle ergometry and, approximately 60 min later, light swimming (2 to 3 x 2 min; speed v = 0.33 +/- 0.02 m.s-1; T = 28 degrees C). The changes in heart rate, blood pressure, lactate, glucose, adrenaline and noradrenaline levels during the swimming exercise were equivalent in mean value to ergometry at the 100 W level. Three patients had to discontinue swimming before the scheduled time, due to considerable arrhythmias. Three other patients stopped swimming because of subjective overexertion. The exercise reaction was less favorable among those unaccustomed to swimming than among regular swimmers.

Adult↗
PubMed1988

[Differential diagnosis: physiologic-pathologic hypertrophy of the heart. A case report].

We report on a 52-year-old asymptomatic patient, whom we have examined regularly since 1981. The principal finding is a marked terminal negativity of the T-wave in the extremities and left precordial chest leads in the electrocardiogram with regression at high exercise levels. The patient engages intensively in sports (running, cross-country skiing, gymnastics). His performance capacity is above normal at 4.5 (1981) and 3.8 watts/kg body weight (1988). The echographically determined left ventricular muscle mass (LVM) increased from 2.1-2.3 g/kg body weight to 2.9 g/kg, the end-diastolic thickness of the septum from 9 to 13, and the posterior wall from 8 to 12 mm. In physiological cardiac hypertrophy (athlete's heart), a LVM of 2.9 g/kg is not unusual, whereby the end-diastolic wall thickness does not, exceed 10 to 11 mm and the mass-volume ratio (LVM/end-diastolic ventricular volume) remains constant (about 1.2 g/ml) in contrast to the 1.75 g/ml in our patient. Thermodilution catheter examination of the heart showed a pathological increase in mean pulmonary capillary pressure (26 mm Hg) under exercise as an indication of impaired left-ventricular function. Normal myocardial scintigraphy (resting and exercise) and a lack of symptoms permit the exclusion of relevant coronary heart disease. We diagnosed non-obstructive hypertrophic cardiomyopathy. The problems of differentiating between physiological and pathological cardiac hypertrophies are discussed.

Cardiac Volume↗
PubMed1987

Activation of sodium transport in human erythrocytes by beta-adrenoceptor stimulation in vivo.

Beta-adrenoceptor stimulation in vivo shifts potassium into the cells. To examine whether human erythrocytes participate in this process, we measured, along with serum or plasma potassium, the concentrations of potassium and sodium in erythrocytes. Beta-adrenoceptor stimulation was obtained by infusion of either fenoterol or hexoprenaline into 6 volunteers at rest or by endogenous amines provoked in 14 volunteers during ergometric exercise. Metabolic effects were followed at rest on serum insulin, C-peptide, and growth hormone levels, and during exercise on pH on lactate concentration in blood. The potassium concentration (mean +/- S.E.M.) dropped (p less than 0.01) in serum from 4.64 +/- 0.37 to 3.19 +/- 0.43 mmol x l-1 in the first hour at rest and in plasma from 5.70 +/- 0.93 to 4.63 +/- 0.45 in 90 sec directly after exercise. The concentration of erythrocyte sodium dropped (p less than 0.001) from 9.68 +/- 0.73 to 8.81 +/- 0.62 mmol x l-1 in cells and from 9.62 +/- 1.16 to 8.55 +/- 1.24 during exercise for 90 s, respectively. Changes in the concentration ratio of cellular sodium to potassium confirmed this sodium shift. An increased sodium transport in erythrocytes due to beta-adrenoceptor stimulation in vivo appears to complement a shift of serum potassium into the cells and may be mediated by the membrane-bound sodium, potassium ATPase.

Adult↗
PubMed1987

[Effect of vitamins and iron on performance and recovery in humans and in sports anemia].

In sports, vitamins along with minerals, particularly iron, and the energy nutrients such as carbohydrates, are considered especially important. Frequently single or multiple vitamins in combination with other active substances such as iron, other minerals or carbohydrates are administered. In sports, vitamins are added to carbohydrate mixtures or electrolytes enriched with vitamins are offered and frequently used. There is no doubt that due to the numerous effects of vitamins, a connection must exist between the vitamin status and athletic performance capability. It can be concluded that vitamin deficiencies have a negative effect on physical and mental performance. The release of energy can only attain its maximum output when the organism has the required substances at its disposal. Iron is of central importance among these active substances, since its presence in haemoglobin is essential for the transport of oxygen and carbon dioxide, makes it possible for myoglobin to function as an oxygen supply depot and guarantees the functioning of internal respiration in the respiratory chain and various key enzymes. Muscle training increases not only the respiratory chain but also several other iron-rich enzymes. This makes even more astonishing the fact that a variety of recently published articles report on iron deficiency among athletes. The effect of the iron deficiency with anaemia (sports anaemia) is manifest in a reduction of aerobic capacity with an increase in lactate acidosis, greater fatigue, loss of appetite, muscular cramps and vasomotor disturbances.

Anemia, Hypochromic↗
PubMed1987

Sensitivity of the physiologically hypertrophied heart to isoproterenol.

Cardiovascular reactions to isoproterenol stimulation (2 and 4 micrograms/min for 12 min each) were evaluated in seven endurance-trained athletes (marathon runners, VO2 max 66.0 +/- 3.7 ml/kg) and seven untrained subjects (VO2 max 54.4 +/- 3.6 ml/kg). At rest and during stimulation, the heart rate, blood pressure as well as one-dimensional (end-diastolic and end-systolic dimensions, shortening fraction) and two-dimensional (end-diastolic and end-systolic volumes, ejection fraction, stroke volume, cardiac output) echocardiographic parameters were determined. The increase in the heart rate of the endurance-trained athletes (28%; 2 micrograms/min) (58%; 4 micrograms/min) was less than in the untrained controls (34%/76%). The blood pressure behaved similarly in both groups. The stroke volume of the endurance-trained subjects rose during stimulation (14%, 4 micrograms/min); the end-diastolic volume remained nearly constant as the end-systolic emptying increased. The stroke volume of the untrained subjects tended to decrease as the end-diastolic and end-systolic volumes were reduced. In absolute terms, the shortening fraction and ejection fraction were identical. Referring to the heart rate, however, they were elevated in the endurance-trained subjects. Hence, under isoproterenol the rise in heart rate was weaker and the increase in ventricular performance seemed to be stronger in the trained subjects compared to the untrained controls. The causes appear to be different regulative effects of the autonomic nervous system on the sinus node and the ventricular myocardium; intrinsic cardiac mechanisms remain to be discussed.

Adult↗
PubMed1987

Influence of symptom-limited stress on blood lactate behaviour in coronary heart disease (CHD) patients.

In order to document the possible influence of stress limiting factors (STLF: chest pain, ST-segment depression) on exercise-induced blood lactate increase in CHD patients (post myocardial infarction) 88 males were examined in a stepwise bicycle stress test. Blood lactate samples were drawn at the end of each stress step. The patients were divided into 2 groups without (n = 45) and with (n = 43) STLF, higher blood lactate concentrations, however, were only observed in relation to the exercise intensity reached at the end of the stress test. Neither the symptom chest pain nor the degree of ST-depression showed a significant influence on the physical performance capacity and the lactate concentration at the anaerobic threshold. Nevertheless, a physical performance capacity above 1 W/kg seems to be necessary to reach the anaerobic threshold level. When the lactate measurement is used in CHD patients, the influence of age on the maximum lactate concentrations must be considered.

Aged↗
PubMed1987

Physical training, vegetative regulation, and cardiac hypertrophy.

Dynamic physical training leads to functional and structural adaptations in the cardiovascular system. Functional changes, such as bradycardia, occur after only relatively little training and in advance of structural changes. They are the result of elevated parasympathetic tone at rest and reduced sympathetic activity in the submaximal range. Sympathetic activity cannot be correlated only with the plasma catecholamine level because the affinity and density of the beta-receptors and alpha receptors are influenced by training. In humans, endurance training appears to result in an elevation in beta 2-receptors and a decrease in alpha 2 receptors; the results of animal experiments are discrepant. Conformant, however, is the increased responsiveness of the myocardium to isoproterenol with respect to the mechanical response. Independent of this, other changes at the membrane level must be discussed since the intrinsic heart frequency is reduced in athletic individuals following autonomic blockade, even before hypertrophy can be observed. The functional changes remain intact or intensify when cardiac hypertrophy is induced by increased training. The maximum values for training-induced hypertrophy [left ventricular muscle mass (LVM) = 3.5 g/kg] are about 70-80% of the baseline weights (LVM = 2.1 g/kg). The left ventricle is enlarged during end diastole and end systole, the ejection fraction is normal, and the stroke volume is increased. The mass/volume ratio remains constant (LV = 1.2 g/ml), as does the maximum systolic wall stress (196 x 10 dyn/cm). Compared with pathological forms of hypertrophy and to the normal heart, the trained heart is capable of increasing the stroke volume considerably with exercise and maintaining the increase to a high-frequency range.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomegaly↗
PubMed1987

[Echocardiographic contractility reserve and invasive hemodynamics in physical stress in probands with healthy hearts and patients with dilated cardiomyopathy].

In the present study, 17 patients with angiographically proven dilative cardiomyopathy (CM) were investigated simultaneously by both invasive right heart catheter and 1D/2D echocardiography at rest (R) and during bicycle exercise (E) stress test. They were compared with 14 normal subjects (N). The echocardiographic contractility reserve was determined as an increase in the systolic pump function (shortening fraction-SF, ejection fraction - EF) and compared with pulmonary capillary wedge pressure during exercise. 14/17 echocardiograms of dilative cardiomyopathy and all echocardiograms of normal subjects at rest as well as during exercise could be accepted. In N, echocardiographic parameters of systolic function significantly increased during exercise, whereas dilative cardiomyopathy showed decreased contractility reserve with no increase in pump function (for CM patients, at rest SF: 21.3% +/- 8%; EF: 41.6% +/- 14%; exercise SF: 21.3 +/- 9%; EF: 40.7% +/- 15%). Hemodynamic investigation in CM showed no increase in stroke volume accompanied by a pathologic increase in pulmonary wedge pressure, ranging from x = 16.4 mmHg at rest, up to 30.0 mm Hg in exercise (p less than 0.001), whereas in normal subjects, no pathologic increase in pressure was present (from 10.3 mm Hg at rest to 13.7 mm Hg during exercise). There were closed relations between invasive and non-invasive data. The relative alteration of stroke volume during E showed in N and in CM good correlation with echocardiography (N + 19%, CM -2%) and invasive data (N + 18%, CM + 2%). FSe during stress and PCPm showed a closed inverse correlation during exercise (p less than 0.001; r = 0.8). The lower the contractility in echocardiogram, the higher PCPm was in exercise.

Cardiac Output↗
PubMed1986

Apolipoprotein profile in healthy males and its relation to maximum aerobic capacity (MAC).

In order to document possible variations of apolipoproteins in relation to the maximum aerobic capacity, 36 healthy young males of different aerobic performance were examined and the serum concentrations of apolipoprotein A-I, A-II, B, C-II, C-III, E investigated. In contrast to all other lipoproteins, significant differences between the endurance-trained and control subjects could be found in the apo A-I concentrations only (1025 +/- 92 vs 1456 +/- 179 mg/l, p less than 0.001). In addition, the apolipoprotein A-II, B, C-II, C-III, E concentrations correlated neither with the maximum aerobic capacity values nor with the relative body weight of the subjects.

Adolescent↗
PubMed1986

[Catecholamine behavior, adrenoreceptor density of intact cells and sensitivity to catecholamines in a patient with orthostatic hypotension].

We evaluated sympathetic nervous system function in a patient with primary orthostatic hypotension. Plasma catecholamine levels--except for dopamine levels--and urinary catecholamine excretion were decreased, alpha-adrenoreceptor responsiveness to noradrenaline and beta-adrenoreceptor responsiveness to isoproterenol were increased according to increased beta-2-adrenoreceptor density on intact polymorphonuclear leukocytes. Alpha-2-adrenoreceptor density on intact platelets and adrenaline-induced platelet aggregation in vitro, however, were unchanged. We evolved a therapeutic regimen with fludrocortisone, propranolol, and dihydroergotamine that allowed the patient to resume nearly a regular degree of mobility.

Aged↗
PubMed1986

Urinary excretion of free noradrenaline and adrenaline related to age, sex and hypertension in 265 individuals.

Urinary excretion of free noradrenaline and adrenaline during 24 h in 265 individuals was determined and related to sex, age, and hypertension as one indicator of the average sympathetic drive. Noradrenaline was found to correlate positively with age in healthy individuals. Noradrenaline and adrenaline were lower in healthy women than in men during the first half of life expectancy. Catecholamine excretion was similar in men and women in the second half of life expectancy. In hypertensive individuals, catecholamine excretion was slightly higher in the first half, and significantly higher in the second half of life expectancy. We assume that the differences in catecholamine excretion can contribute to the sex-and age-related differences in incidence of cardiovascular diseases, such as hypertension and coronary heart disease.

Adult↗
PubMed1986

Sex-related differences in free plasma catecholamines in individuals of similar performance ability during graded ergometric exercise.

Sex-related differences of catecholamine responses were evaluated in nine healthy women and six age-matched men at rest and during incremental treadmill exercise. Heart rate, oxygen uptake (VO2), glucose and lactate blood levels as well as the free plasma catecholamines, noradrenaline and adrenaline, were determined. No significant differences were observed for these parameters between the two groups at rest. The females had relative VO2max and maximal running velocities similar to the males, which points to a comparable dynamic performance ability. However, at identical work loads, noradrenaline, adrenaline and glucose levels were significantly higher in women than in men. Lactate, heart rate and relative VO2 showed a similar tendency at submaximal exercise levels, indicating higher strain at identical stress levels in women. The reason for the higher sympathetic activity in women at identical work loads may be their relatively smaller skeletal muscle mass in relation to the loads during this test.

Adult↗
PubMed1986

Age-associated changes of exercise-induced plasma catecholamine responses.

Age-associated plasma catecholamine responses were evaluated in 10 young (25 +/- 3 years) and 11 older competition cyclists (66.2 +/- 6 years) during incremental ergometric cycling. Noradrenaline levels were higher in the older subjects at rest, at identical work loads and at exhaustion. Adrenaline levels were similar in both groups at rest, higher in the old test subjects at identical work loads and lower in the old subjects at exhaustion. The noradrenaline-adrenaline ratio changed significantly depending on age from 5.1 +/- 0.5 to 8.7 +/- 2.1 which indicated higher adrenaline-related noradrenaline responses. The observed age-related differences may be caused by a compensatory mechanism which depends both on negatively age-correlated physical fitness, and on the decreased sensitivity of the organism to beta-adrenergic stimulation with age, as well as on an age-dependent change in the clearance of catecholamines from the circulation as described by Esler et al. (1981).

Adult↗
PubMed1986

Free plasma catecholamines, heart rates, lactate levels, and oxygen uptake in competition weight lifters, cyclists, and untrained control subjects.

Responses of free plasma noradrenaline and adrenaline were evaluated in 10 competition cyclists, 8 competition weight lifters, and 9 untrained control subjects during exhaustive, incremental cycling. Ergometric performance and oxygen uptake ability were 403 +/- 20 W and 65.8 +/- 4.7 ml X kg-1 for the cyclists, 294 +/- 42 W and 47.2 +/- 4.6 ml for the weight lifters, and 296 +/- 40 W and 46.7 +/- 9.4 ml for the control subjects. At 100- and 150-W levels, noradrenaline was significantly lower in cyclists and weight lifters, and in cyclists also at 200- and 250-W levels, related to the other groups. No significant noradrenaline differences were seen between the three groups at their respective exhaustion levels. Compared with the control subjects, adrenaline responses were lower in cyclists and weight lifters at all identical work loads. The weight lifters showed the lowest levels of all three groups, even at their exhaustion level, which indicates an alteration of the adrenaline-noradrenaline ratio. Dynamically and statically trained subjects exhibit a similar training-related control of sympathetic activity. An increased vagal tone, however, only occurs in conjunction with dynamic endurance training.

Adult↗