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Biomedical subjects

J Keul

Publications and source records attributed to J Keul.

At least 235 records · Page 13Linked to original sources
PubMed1979

[Echocardiography during ergometric exercise (author's transl)].

Radiological heart volume estimations and echocardiographic studies were performed on 30 male and 15 female middle distance athletes at rest, during supine ergometric exercise at 10 and 100 Watt and 1 minute after excerise. During exercise, there is an increase in cardiac output, in the small hearts of 6%, in the large hearts of 16%, due to a small enddiastolic increase and an associated decrease in the endsystolic left ventricular diameter. At rest and at 50 Watt, the cardiac output, corrected for body surface area, was practically the same for all volunteers, at 100 Watt the volunteers with the largest hearts had the highest cardiac output. This is interpreted as evidence for increased cardio-circulatory reserves. The contractility parameters at the various exercise grades varied dependant on heart size; when related to heart rate the variations were practically abolished. The results suggest that variations in the dynamics of small and large hearts are not primarily due to intrinsic factors but rather related to extrinsic factors such as sympathetic drive expressed by the changes in heart rate.

Adolescent↗
PubMed1979

The significance of the aerobic-anaerobic transition for the determination of work load intensities during endurance training.

Anaerobic and aerobic-anaerobic threshold (4 mmol/l lactate), as well as maximal capacity, were determined in seven cross country skiers of national level. All of them ran in a treadmill exercise for at least 30 min at constant heart rates as well as at constant running speed, both as previously determined for the aerobic-anaerobic threshold. During the exercise performed with a constant speed, lactate concentration initially rose to values of nearly 4 mmol/l and then remained essentially constant during the rest of the exercise. Heart rate displayed a slight but permanent increase and was on the average above 170 beats/min. A new arrangement of concepts for the anaerobic and aerobic-anaerobic threshold (as derived from energy metabolism) is suggested, that will make possible the determination of optimal work load intensities during endurance training by regulating heart rate.

Adult↗
PubMed1979

[Echocardiographic studies on athletes of various sport-types and non-athletic persons (author's transl)].

The results of echocardiographic studies on 90 athletes representing various sport-types and 18 non-athletic persons are presented. The intracardiac diameter measured by echocardiography was proportional to the heart volume determined radiologically. The thickness of the septum and posterior heart wall compared to the internal heart diameter was greater in athletes with static exercise than in endurance athletes. This must be interpreted as a tendency to concentric hypertrophy. In endurance athletes this relationship tended to be less than in non-athletic persons. In addition stroke volume and cardiac output at rest was higher in endurance athletes than in athletes with static exercise and non-athletic persons. At rest no variations in parameters of heart muscle contractility related to heart size or sport-type could be detected.

Adult↗
PubMed1979

[Echocardiographic results in female athletes, nonathletic women and patients with arterial hypertension (author's transl)].

Echocardiographic studies and radiological measurements of heart volume were performed in 30 female track athletes, 17 female shot-putters or javelin throwers, 12 nonathletic women and 8 female patients with arterial hypertension. The following observations were made: The hearts of the female athletes undergoing endurance training were in the whole larger than the hearts of the nonathletic women, although the ratio of internal diameter to wall thickness was unchanged. There was a relative increase in the ratio wall thickness to internal left ventricular diameter in the female shot-putters and javelin throwers compared to the nonathletic females. This is interpreted as being a result of the static training imployed. In all female patients with severe arterial hypertension the heart wall thickness was increased, the internal heart diameter was dependant of the stage of the illness. Using echocardiography it is possible to draw conclusions as to the ratio wall thickness to cavity diameter. This is not possible with radiological heart volume studies.

Adolescent↗
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

[Echocaridographic measurements of left ventricle, heart volume, and maximal oxygen uptake (author's transl)].

Echocardiograms, radiological heart volume and datas by treadmill-exercis of 50 endurance athlets were studied. There was a highly significant correlation between radiological heart volume and left ventricular dimension as well as left ventricular volume including stroke volume. Other good relations were found between echocardiographic measurements and maximal oxygen uptake. These findings of left ventricular echocardiographic dimensions compared with heart volume and oxygen uptake support the value of this method and permit its use in the analysis of physiological and pathologic changes.

Adolescent↗
PubMed1978

Serum alanine assay with an enzymic micromethod (L-alanine dehydrogenase).

L-Alanine was measured by an enzymic micromethod in serum after treatment with perchloric acid, as well as after ultrafiltration through collodium membrane filters. Serum L-alanine was also determined by an automated column chromatographic technique. Using the enzymic method, spuriously increased L-alanine levels could be obtained due to the absorbent reaction between hydrazine and NAD-containing reagents. It could be shown that this absorbent reaction depends on the pH value of the test solution. In contrast to supernatant diluted by perchloric acid, ultrafiltrates gave L-alanine data equivalent to those by column chromatography, since conditions of reaction time and pH value could be kept identical for blank, standard and ultrafiltrate solutions.

Adult↗
PubMed1978

The effect of weight lifting exercise on heart rate and metabolism in experienced weight lifters.

Fifteen experienced weight lifters were investigated to examine the effects of weight exercise with variable intensity on heart rate and changes in arterial glucose, lactate and pyruvate, as well as serum total lipids, beta-lipoproteins, triglycerides, glycerol and free fatty acids. The highest value of heart rate were reached during repetitions (ca. 150 beats/min), during single maximal contraction only 120--130 beats/min. No important changes were found in lipid substrates or glucose, while lactate (x max: 4 mmol/l) and urivate (x max: 0.11 mmol/l) increases were moderate. This type of training may be useful in the clinical rehabilitation of the locomotor system but it lacks importance for preventive or rehabilitation therapy of the cardiovascular system.

Adult↗
PubMed1977

Physical exercise after induced alkalosis (bicarbonate or tris-buffer).

The influence of bicarbonate and Tris-buffer infusions on the performance capacity for maximal, brief exercise (400 m run) was studied using 10 normal males in their twenties. Run time, maximal lactate concentration and heart rate remained unchanged after the buffer infusions. As a result of the induced elevated buffering capacity, the average pH after exercise was about 0.1 unit higher. Corresponding values for base excess and standard bicarbonate were found. The arterial pCO2 was higher after infusion as a result of the active respiratory compensation. Since the reduction in the work-related metabolic acidosis by the buffering substances caused no improvement in performance, the importance of pH as the performance-limiting factor must be questioned because the investigation gave no evidence for alterations of intracellular pH.

Adult↗