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Biomedical subjects

M Lehmann

Publications and source records attributed to M Lehmann.

At least 343 records · Page 19Linked to original sources
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↗
PubMed1981

[The influence of graduated treadmill exercise on plasma catecholamines, aerobic and anaerobic capacity in boys and adults].

Adrenaline, noradrenaline, lactate and glucose levels in the blood, together with the heart rate and oxygen intake were examined in eight boys (12.8 +/- 0.8 years) and seven adults (27.8 +/- 2.9 years) during a graduated treadmill exercise. At rest, noradrenaline is higher in the adults, while adrenaline, lactate, glucose, heart rate and relative oxygen intake show no differences between the groups. At the same exercise levels, adrenaline (+ 90-180%), noradrenaline (+ 28-77%) and the heart rate are higher in boys, corresponding to a higher relative exercise load, and glucose, lactate and the relative oxygen intake show no differences. During maximum treadmill exercise adrenaline, glucose and the relative oxygen intake show no differences between the groups, whereas the noradrenaline (-30%) and lactate levels (-25%) are lower and the heart rate is 4% higher in the boys. There is an identical increase in lactate and catecholamine levels (r = 0.92 and 0.87) with a lower correlation with high intensity "anaerobic" physical exercise, which shows no age dependent difference until about the age of 40. The maximum catecholamine (adrenaline and noradrenaline) and lactate concentration is 25% lower in the boys; an indication of reduced maximum sympathetic activity and reduced maximum anaerobic capacity is seen. The constant relationship between adrenaline and noradrenaline during physical work (r=0.90 and 0.85), also with a lower correlation at high intensive physical exercise, changes from 1 : 3.5 (boys) to 1 : 5.5 (adults) (p less than 0.001), based on higher noradrenaline levels in the adults at rest, at submaximum exercise levels and during maximum ergometric work; these changes are seen to be the cause of an age dependent negative chronotropic effect.

Adolescent↗
PubMed1981

[Plasma catecholamines and aerobic-anaerobic capacity in women during graduated treadmill exercise].

Blood levels of adrenalinee, noradrenaline lactate, and glucose, and heart rate and oxygen intake were examined in nine healthy women (29.3 +/- 2.2 years) during a graduated treadmill exercise. At rest there are no differences in these parameters compared with male subjects. During treadmill exercise, two ranges can be distinguished as in male subjects. A range with a slight increase in adrenaline, noradrenaline, and lactate, corresponding to a predominantly aerobic energy supply, and a range with an eight to ten times higher increase of adrenaline, noradrenaline, and lactate related to an additionally increasing anaerobic energy supply. The transition between the two ranges corresponds approximately to the anaerobic threshold, and occurs as in male subjects at an oxygen intake and heart rate of 70--80% and a catecholamine and lactate concentration of 20--30% of the maximal value. At the same exercise level, adrenaline, and noradrenaline are higher than in male subjects. Differences in the relative oxygen intake or the heart rate are similar. During maximal treadmill exercise adrenalin increased by 1,300%, noradrenaline, 1,500%, lactate 1,100% glucose, 30%, the oxygen intake, 1,000%, and the heart rate by about 200%. During ergometric exercise, as in male subjects there is a direct linear correlation between adrenaline and noradrenaline. A direct linear correlation excists between the catecholamines and lactate or glucose levels. Referring to the catecholamines, the lactate level is lower than in male subjects, corresponding to a limitation of acidosis in females.

Adult↗
PubMed1981

Plasma catecholamines in trained and untrained volunteers during graduated exercise.

Ten untrained subjects and nine trained cyclists were examined during graduated ergometric exercise in the supine position. The levels of epinephrine and norepinephrine in the blood as well as the heart rate and oxygen intake were determined. At submaximum levels, epinephrine, norepinephrine, lactate, and the heart rate are lower in tthe trained than in the untrained subjects; the relative oxygen intake shows no significant difference. The ergometric work capacity is approximately 30% higher in the trained cyclists. During maximum ergometric exercise, the plasma catecholamines, lactate, and the heart rate show no differences between the two groups; the oxygen intake is approximately 30% higher in the trained than in the untrained subjects. A direct relationship exists between catecholamine levels and lactate; however, this relationship becomes less exact during higher exercise intensities: In reference to the same catecholamine concentration, the lactate levels as well as the submaximum heart rates are higher in the trained than in the untrained subjects, the cause of which could be an increased beta-adrenoceptor sensitivity in the trained subjects.

Adult↗
PubMed1981

Comparative echocardiographic examinations in sitting and supine position at rest and during dynamic exercise.

Echocardiograms of 12 healthy male subjects in the supine and sitting positions were obtained. The end-diastolic (EDD) and end-systolic (ESD) diameters of the left ventricle were measured, and the stroke volume was calculated as the cube of the diameter. A significantly (P less than 0.001) smaller stroke volume was found in the sitting rest position (67.1 ml) compared to the supine rest position (92.3 ml). During dynamic exercise, the stroke volume increase in the sitting position (29.7%) was considerably higher than in the supine position (13%). The shortening fraction showed no difference in the sitting and supine positions at rest and during dynamic exercise. The results demonstrate good agreement between the echocardiographic method and other noninvasive procedures.

Adult↗
PubMed1981

[Effect of bunitrolol on heart rate, metabolic parameters during physical exercise, and performance].

Plasma catecholamines, glucose, lactate, free fatty acids, and glycerol in the blood, as well as heart rate, oxygen intake, and work capacity have been examined in 9 healthy subjects (28.5 +/- 2 years) at rest, during submaximum and maximum ergometric exercise, after oral administration of a placebo and of 10 mg O-[3-(tert.-butylamino)-2-hydroxypropoxy]-benzonitril (bunitrolol, Stresson), respectively. The results are as follows: 1. As caused by the intrinsic activity of bunitrolol, the heart rate does not show nearly any reduction at rest and during submaximum physical exercise. At maximum exercise level the heart rate is 37 beats/min lower with bunitrolol. The limitation of heart function leads to a work capacity reduction of approx. 14%. 2. After administration of bunitrolol, adrenaline level is significantly lower at rest and during submaximum exercise than with placebo. At a 200 W level, the concentration is higher with bunitrolol, but the maximum results are not attained with placebo. In relation to the percentile of the maximum work capacity, plasma catecholamine level shows no differences with placebo and with bunitrolol, respectively, except that it is lower during maximum exercise and the recovery phase. 3. Glucose, free fatty acids, and glycerol levels show no significant changes with bunitrolol. Lactate decreases significantly after bunitrolol at submaximal exercise levels and during the recovery stage, which can be looked upon as an indication of a glycolysis restriction.

Adult↗
PubMed1981

Effect of static and dynamic exercise on heart volume, contractility, and left ventricular dimensions.

Echocardiographic measurements in 90 successful athletes were compared with data from untrained subjects and patients with hypertension and cardiomyopathy. The athletes represented sports disciplines requiring predominantly static exercise and power training (weight lifters, hammer-throwers, shot putters) and dynamic or endurance exercise (middle and long distance runners, cyclists, nordic skiers, rowers). The left ventricular end-diastolic diameter in well-trained endurance athletes was increased from the normal mean of 47.8 to 53.6 mm. The relationship of ventricular wall thickness to end-diastolic diameter was not affected. With static training, an increase of the end-diastolic diameter in relation to body weight did not occur, but there was a definite increase of septal and posterior wall thickness with an altered ratio between end-diastolic diameter and wall thickness. The ratio stroke volume:heart volume was increased in endurance athletes, but decreased in power athletes. The shortening fraction was not altered by these various forms of training. The ejection fraction was increased in endurance athletes whereas power-trained athletes showed a moderate decrease. There was no indication of myocardial damage in power- or endurance-trained athletes. The critical threshold that is associated with damage is apparently not exceeded during athletic training.

Blood Pressure↗
PubMed1981

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

7 healthy male subjects, 17 patients with left heart failure of degree I and II and 14 patients of degree III and IV (3 patients) based on a coronary heart disease were examined at rest and during ergometric exercise in supine position during a right-heart-catheter examination. Three patients degree IV were not exercised. Compared to healthy subjects, the patients showed, according to disease severity, catecholamine level increases at rest and at the same submaximum exercise intensity. The catecholamine levels show no difference between the patients and healthy subjects during maximum ergometric exercise, although the patients exercise load was 30% (degree I and II) and 60% (degree III) lower. Three patients of the degree IV already have plasma catecholamine levels at rest like those of healthy subjects during maximum ergometric exercise at 155 +/- 33 Watts. Adrenaline and noradrenaline show a direct correlation to pressure dimensions as to the PCPm or the PAPd corresponding to the limitation extent of cardiac function. Estimation of plasma catecholamines in left heart failure during ergometric exercise allows an orientational judgement of the course of hemodynamic dimensions such as PCPm, PAPd and HMV without renewed invasive diagnostic.

Catecholamines↗
PubMed1980

Biosynthesis of bacterial glycogen: purification and properties of Salmonella typhimurium LT-2 adenosine diphosphate glucose pyrophosphorylase.

The adenosine diphosphate glucose pyrophosphorylase from a Salmonella typhimurium LT-2 mutant, JP102, derepressed in the glycogen biosynthetic enzymes was purified to homogeneity. The enzyme was found to be identical with the parent wild-type enzyme with respect to regulatory properties, immunological reactivity, and kinetic constants for the allosteric effectors and for the substrate, adenosine triphosphate. The JP102 enzyme was composed of four identical subunits, each with a molecular weight of about 48,000. This was supported by the findings that (i) gel electrophoresis under denaturing conditions showed only one component; (ii) digestion with carboxypeptidase B released stoichiometric amounts of arginine, and (iii) amino-terminal sequencing showed a single sequence for the first 27 residues. The properties of the purified S. typhimurium enzyme were compared with the properties of the previously purified Escherichia coli B enzyme.

Adenosine Diphosphate Glucose↗
PubMed1979

[Adrenalin and cardiac output in pregnancy (author's transl)].

The heart rate performance, cardiac output and catecholamine excretion were observed at rest in the ergometer test (40 min at 50 watts) in a group of 8 pregnant women whose case history and clinical record did not reveal any abnormal findings, during the course of pregnancy (20th, 28th and 36th weeks of pregnancy) as well as 2 and 12 weeks post partum. It was found that the cardiac output increased, dependent upon the heart rate, the stroke volume remaining approximately constant (max. + 60%) during pregnancy, compared with the controls post partum. There is a close linear correlation (r = 0.983) between the measured heart rates and the corresponding excretion of epinephrine (adrenalin) with the urine at rest and under load. It may be assumed that there is a causative link between the increase in secretion of catecholamine by the mother and the well-known change in cardiac output during pregnancy.

Adult↗
PubMed1978

Continuous cultivation in a chemostat of the phototrophic procaryote, Anacystis nidulans, under nitrogen-limiting conditions.

Anacystis nidulans was grown photoautotrophically in a chemostat in the presence of light, air and CO2 as the sole carbon source. Either the amount of the nitrogen source in the medium or light intensity were used as growth-limiting parameters. 1. Cells of high glycogen content obtained by pre-incubation under nitrogen starvation conditions maintained their glycogen content during continuous cultivation. Both growth rate and the amount of cell-mass and of glycogen depended on the nitrate content of the medium and the light intensity. The values for the growth rate, the maximal rates of glycogen synthesis and of cell mass formation were 0.1 h-1, 6 mg/l.h and 17 mg/l.h, respectively. 2. Cells without glycogen which had been transferred from an exponentially growing batch culture to chemostat conditions showed increasing rates of growth and of cell mass formation when the light intensity was increased. A determination of specific values resulted in 0.15 h-1 for growth rate and 23 mg/1.h for cell mass formation. 3. The chemostat apparatus is described in detail.

Cell Division↗