Search PubMed⌕ Search

Biomedical subjects

A Schnabel

Publications and source records attributed to A Schnabel.

At least 109 records · Page 6Linked to original sources
PubMed1983

Assessment of anaerobic capacity in runners.

A new method for assessment of anaerobic capacity is presented. It consists of two treadmill runs at 22 km X h-1 and 7.5% slope, the first one being interrupted after 40 s (submax. test), the second continuing until volitional exhaustion (max. test). Measured variables are the increase in arterial lactate concentration over the pre-exercise value in the submax. test (delta L40), the maximal arterial lactate level in the max. test (Lmax), and time to exhaustion (tmax). Fifty-five male runners of high competitive level were examined with this procedure, including 400-m runners of differing performance capacity (400 m A and B/C), middle-distance (MD), long-distance (LD), and marathon runners (M). Eleven physical education students served as controls (C). tmax was 88.3 +/- 11.0, 85.2 +/- 11.4, 83.1 +/- 12.7, 63.1 +/- 11.4, 43.7 +/- 7.5, and 50.7 +/- 5.0 s for 400 m A, 400 m B/C, MD, LD, M, and C. The corresponding values for Lmax were 17.47 +/- 1.68, 17.52 +/- 2.03, 16.27 +/- 2.18, 13.44 +/- 2.13, 10.13 +/- 2.68, and 15.54 +/- 1.43 mmol X 1(-1) and for delta L40 5.93 +/- 1.10, 7.13 +/- 1.55, 6.39 +/- 0.89, 6.68 +/- 1.18, 8.19 +/- 1.37, and 10.76 +/- 1.62 mmol X 1(-1). The differences in delta L40, most likely reflecting differences in high energy phosphate utilization, suggest that excellent performance in any running event is associated with increased alactacid anaerobic capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Effect of beta-adrenergic blockade on supramaximal exercise capacity.

Fourteen male physical education students performed a single bout of running until exhaustion on the treadmill at 22 km/h and 7.5% slope. They received single oral doses of 100 mg bupranolol (nonselective beta-blockade), 100 mg metoprolol (beta-1-selective blockade), and placebo 60-90 min before running. Arterialized capillary blood was sampled repeatedly until 30 min after exercise for assessment of lactate and glucose. Adrenaline and noradrenaline were determined in venous plasma before and immediately after exercise. Running time until exhaustion was 49.3 +/- 2.3 s in the control experiment, 44.5 +/- 2.0 s with metoprolol, and 42.7 +/- 2.0 s with bupranolol. The reductions under beta-blockade were statistically significant. With both beta-blockers the increases of the lactate and glucose blood levels were significantly reduced, the levels being almost identical with metoprolol and bupranolol. The post-exercise levels of adrenaline and noradrenaline did not differ significantly between the control, metoprolol, and bupranolol experiments. It is concluded that determination of the lactate and glucose levels in blood did not allow assessment of the mechanism by which beta-blockade impairs the capacity for supramaximal exercise. Besides reduced anaerobic energy release due to inhibition of glycogenolysis, other beta-blocker effects are considered.

Adrenergic beta-Antagonists↗
PubMed1982

[Catecholamines, GH, cortisol, glucagon, insulin, and sex hormones in exercise and beta 1-blockade (author's transl)].

The effects of beta-1-adrenergic blockade (100 mg metoprolol) on metabolism in exercise was examined in 14 healthy males who worked for 50 min on a treadmill at 65% of their maximal exercise capacity. The tests were carried out in a double blind fashion. Glucose and lactate were determined in arterialized capillary blood, free fatty acids, glycerol, growth hormone, cortisol, glucagon, insulin, testosterone, and estradiol in serum, and adrenaline and noradrenaline in plasma. Lactate and glucose were not significantly affected by beta-1-adrenergic blockade, free fatty acids and glycerol were reduced by 50% and 30% respectively as compared with the unmedicated condition. Adrenaline and noradrenaline levels were increased by 104% and 54% respectively, growth hormone by 60%, cortisol by 72%, and glucagon by 36% when compared with the control experiments. Insulin and estradiol were unaffected, testosterone was depressed by 21% under medication. The results demonstrate that during prolonged exercise beta-1-adrenergic blockade depresses lipolysis. Energetic deficiency is prevented by counter-regulatory increases of various hormones. Consequently, from the metabolic point of view there is no indication of impairment of prolonged exercise capacity under beta-1-adrenergic blockade.

Adrenergic beta-Antagonists↗
PubMed1982

[Lipoprotein cholesterol in different physical activities. A comparative study in healthy individuals of different ages and patients with coronary heart disease (author's transl)].

The effects of habitual sporting activity on the serum lipoprotein pattern were examined in 415 males with differing physical activity levels, differing fitness conditions, and differing ages. Of these, 260 were competitive athletes in different events between the ages of 17 and 30 years, 37 were amateur sportsmen, and 20 sedentary individuals of the same age served as control. Sixty amateur sportsmen between the ages of 40 to 60 years in different sporting activities were compared with 19 healthy sedentary controls and 19 patients with coronary heart disease of the same age. Independently of age, the physically active tended to have a reduced LDL-cholesterol, the reduction was statistically significant in some events. No relationship was apparent between the type of physical activity and the magnitude of the LDL-cholesterol reduction. In the sportsmen HDL-cholesterol tended to be higher. In the events demanding a high aerobic capacity the elevation was statistically significant. A positive correlation between HDL-cholesterol or HDL-/total cholesterol, respectively, and maximal oxygen uptake was found. In the majority of events the reduction in total serum cholesterol was not statistically significant. The results demonstrate that habitual sporting activity in events with dynamic exercise involving large muscle groups goes along with a lipoprotein pattern, which in epidemiologic studies has been shown to be associated with decreased coronary risk. This effect is independent on age. The necessary amount of training appears to be equivalent to the amount required to produce the cardiovascular adaptations determined to reduce the risk of coronary heart disease.

Adolescent↗
PubMed1982

Effect of maximal oxygen uptake and different forms of physical training on serum lipoproteins.

260 well trained male sportsmen between 17 and 30 years of age participating in a variety of events were examined for total serum cholesterol and lipoprotein cholesterol and compared with 37 moderately active leisure-time sportsmen and 20 sedentary controls of similar ages and sex. Lipoprotein cholesterol distribution was determined by quantitative electrophoresis. Mean HDL-cholesterol increased progressively from the mean of the sedentary control to the mean of the long-distance runners, indicating a graded effect of physical activity on HDL-cholesterol. In all sporting groups mean LDL-cholesterol tended to be lower than in the controls, no association between LDL-cholesterol and form of training being apparent. Except for the long-distance runners, all sporting groups tended to be lower in total cholesterol than the controls. The HDL-/total cholesterol and LDL/HDL ratios yielded a better discrimination between the physically active and inactive than the HDL-cholesterol alone. Significant positive correlations with maximal oxygen uptake and roentgenologically determined heart volume were found for HDL-cholesterol and HDL-/total cholesterol, and negative ones for LDL/HDL. Differences in the regressions among subsets made up of sporting groups under different physical demands suggest a positive relationship between lipoprotein distribution and the magnitude of the trained muscle mass.

Adolescent↗
PubMed1982

Catecholamines, growth hormone, cortisol, insulin, and sex hormones in anaerobic and aerobic exercise.

Seventeen male physical education students performed three types of treadmill exercise: (1) progressive exercise to exhaustion, (2) prolonged exercise of 50 min duration at the anaerobic threshold of 4 mmol . l-1 blood lactate (AE), (3) a single bout of short-term high-intensity exercise at 156% of maximal exercise capacity in the progressive test, leading to exhaustion within 1.5 min (ANE). Immediately before and after ANE and before, during, and after AE adrenaline, noradrenaline, growth hormone, cortisol, insulin, testosterone, and oestradiol were determined in venous blood, and glucose and lactate were determined in arterialized blood from the earlobe. Adrenaline and noradrenaline increased 15 fold during ANE and 3--4 fold and 6--9 fold respectively during AE. The adrenaline/noradrenaline ratio was 1 : 3 during ANE and 1 : 10 during AE. Cortisol increased by 35% in ANE (12% of which appeared in the postexercise period) and 54% in AE. Insulin increased during ANE but decreased during AE. Testosterone and oestradiol increased by 14% and 16% during ANE and by 22% and 28% during AE. The results point to a markedly higher emotional stress and higher sympatho-adrenal activity in anaerobic exercise. Growth hormone and cortisol appear to be the more affected by intense prolonged exercise. Taking plasma volume changes and changes of metabolic clearance rates into consideration, neither of the exercise tests appeared to affect secretion of testosterone and oestradiol.

Adult↗
PubMed1982

Hormonal and metabolic consequences of prolonged running at the individual anaerobic threshold.

To examine the metabolic and hormonal responses to non-exhaustive steady-state exercise at the individual anaerobic threshold (IAT), 12 male physical education students performed treadmill exercise of 50 min duration. The treadmill speed equaled that at the IAT as assessed in a standardized progressive exercise test (75 +/- 2% of maximal oxygen uptake). Heart rate averaged 177.0 +/- 12.2 min-1 at 15 min and 184.5 +/- 11.5 min-1 at 50 min. After the initial adjustment, arterial lactate stabilized at individually different levels between 2.70 and 6.00 mmol/l without any substantial trend in the individual curves. Arterial glucose was unchanged throughout the test. Glycerol increased continuously to 157% above the preexercise value (P less than 0.001). The FFA blood level was not depressed but rather showed an increasing tendency between 25 and 50 min (P less than 0.05). Between 0 and 25 min, insulin decreased (P less than 0.01), growth hormone increased to 8 times its pre-exercise value (P less than 0.001), and cortisol did not show any significant changes. Between 25 and 50 min, no significant additional changes were detected for these hormones. At 15 min epinephrine and norepinephrine had increased 2.8- and 7-fold above the respective pre-exercise values (P less than 0.001); both catecholamines continued to increase until 50 min (P less than 0.001 and P less than 0.01). It is concluded that prolonged exercise at the IAT is associated with a steady-state condition in carbohydrate supply and turnover, as is suggested by the stable blood levels of glucose and lactate. The stably elevated blood level of lactate did not result in depression of the FFA blood level, suggesting unimpaired supply of FFA from extramuscular sources. Exercise at the IAT places a high load on aerobic metabolism without encountering progressive lactate accumulation and the associated metabolic effects.

Adult↗
PubMed1981

Lactate kinetics and individual anaerobic threshold.

Exercise with stepwise increasing work loads until exhaustion leads to a curvilinear increase of lactate in blood and typical lactate kinetics in the post-exercise period. Lactate kinetics in blood during exercise and recovery results from diffusion along gradients between muscle and blood and simultaneous elimination. Therefore, a general diffusion-elimination model is presented from which maximal rate of elimination (Em), individual anaerobic threshold (IAT), gradient between muscle and blood (deltaC-deltaCEm), muscle volume working above the IAT (Vm), individual membrane constant (Mc), quantity of lactate accounting for lactate gradient (Agrad), and whole body lactate (Anet) can be obtained. For demonstration purpose, this model was applied to a highly trained athlete. In this example, all constants and variables mentioned above as well as an equation reflecting individual lactate kinetics were calculated. Furthermore, the IAT was determined in 61 athletes participating in different events. In general, it can be demonstrated that with increasing aerobic capacity the lactate concentration at the IAT decreases. The lactate concentration at the IAT varies interindividually within broad limits, thus emphasizing the need for individual assessment.

Adolescent↗
PubMed1981

[Metabolic and hormonal response to physical exercise under acute beta 1-adrenergic blockade (author's transl)].

In 14 healthy physical education students the effect of acute beta 1-adrenergic blockade (100 mg metoprolol) on maximal and prolonged exercise capacity, carbohydrate and lipid metabolism, catecholamines, insulin, growth hormone, and cortisol was studied in a double-blind trial. Metoprolol had no effect on maximal oxygen uptake. The 3.5% reduction of maximal exercise capacity had to be attributed to the reduced maximal lactate concentration. Maximal heart rate was reduced by approximately 22%. At submaximal work loads (treadmill) exercise with gradually increasing velocity), lipolysis appeared to be inhibited, arterial glucose and lactate concentrations were unaffected. With metoprolol, epinephrine levels at rest and submaximal work loads were elevated; no effect was apparent at maximal loads. Norepinephrine, insulin, growth hormone, and cortisol were unaffected in exercise with increasing work loads. In prolonged exercise at a constant load of approximately 70% of maximal exercise capacity, mean heart rate was reduced by 26%. Arterial lactate and glucose levels were essentially unchanged, free fatty acids and glycerol decreased by 50 and 30% respectively. With metoprolol, epinephrine increased by 100%, norepinephrine by 50% growth hormone by 60%, and cortisol by 90%, insulin remained unchanged. The results indicate that a reduction of exercise capacity by beta 1-adrenergic blockade in patients undergoing an endurance type training for therapeutic or rehabilitative purposes is unlikely to occur. The inhibition of lipolysis under metoprolol appears to be counteracted by the increased carbohydrate utilisation and by the increased secretion of the regulating hormones.

Adrenergic beta-Antagonists↗
PubMed1976

[Effect of isosorbide dinitrate in relation to posture and age].

Rapid tilting into the 90 degrees upright position after 20 mg ISDN sublingually demonstrates a better orthostatic tolerance of the older group (in spite of a lower cardiac output) in comparison to the younger one. This can be explained by a higher tone of the resistance vessels and a stronger stretch resistance of the arteries of the elastic type (and probably of the veins), which are opposing the hydrostatic effects of orthostasis and guarantee a minor shifting of blood to the lower extremities. The increase of rigidity of the blood vessels with aging declares the better drug resistance of the older group but also points - on the other hand - to the borders of ISDN therapy.

Adolescent↗
PubMedDate not supplied

Occlusive thromboaortopathy (Takayasu disease): clinical and angiographic features and a brief review of literature.

The aim of this study was to evaluate the diagnostic criteria and angiographic classifications of Takayasu arteritis by presenting the clinical, angiographic, and prognostic findings and a prospective follow-up of 78 patients. Occlusive thromboaortopathy or Takayasu arteritis is a large vessel vasculitis. The disease is systemic with an autoimmune and genetic etiology. The complete clinical and angiographic manifestations are reported for 78 cases based on diagnostic criteria of the American College of Rheumatology with a mean 6 +/- 3.2 years follow-up. The mean age was 34.7 and female:male ratio was 3.6:1. According to National Institute of Health criteria, 61.5% of patients were in the acute phase of disease with systemic symptoms such as fever, weight loss, malaise, and elevated C-reactive protein levels. Immunologic markers, such as antinuclear antibody and antineutrophil cytoplasmic antibodies, were negative. The tuberculin test result was positive in 47%. Vascular bruit was present in 89%. Almost all patients had stenoses, occlusions, or aneurysmatic changes of the aorta and its main branches. Hypertension was detected in 58% and left ventricular hypertrophy was initially present in 22 (28%) patients. The angiographic manifestations were classified as type I, cervicobrachial type with 20 cases (25.6%); type II, thoracoabdominal type with 13 cases (16.6%); type III, peripheral type with 10 cases (12.8%); and type IV, generalized type with 35 cases (44.8%). The coronary arteries were involved in 6 cases, pulmonary arteries in 11 initially 5 in follow-up (16 cases), and renal arteries in 28 cases, respectively. A good correlation of the clinical manifestations and the prognosis was observed. During follow-up, five patients suffered from myocardial infarction, six had cerebrovascular accident, seven patients underwent aortic valve replacement, and six patients died (mortality rate, 7.6%). The specificity and sensitivity of diagnostic criteria were 94% and 76%, respectively. In contrast to ours and Nasu's classification in the new classification of Numano, some angiographic types and subtypes of Takayasu arteritis are not present in our patients.

Adolescent↗
PubMedDate not supplied

[Self-inflicted stab wound for simulating self-defense?].

During a violent conflict, a young man was shot dead in front of a bar. The offender stated that he had acted in self defence after having been attacked with a knife. Taking into account the testimonies, the medical findings (f. ex. sonotomogram of the left femur) as well as the crime scene regarding the position of the body, it could not be excluded from the forensic point of view that a knife attack of the later victim had taken place. Nevertheless, the court convicted the man who had shot for murder and gave a life prison sentence.

Adult↗
PubMedDate not supplied

[Death in homes for the aged/nursing homes from the legal medicine viewpoint].

Following the death of 16 inhabitants of a nursing home within a period of 2 weeks, the prosecution ordered legal autopsies in all of the cases, which had not yet been buried or cremated, suspecting a neglect of nursing or active euthanasia respectively. Two out of a total of ten cases revealed drug overdoses which could have explained death. However, due to concurring causes of death, the evidence could not be furnished with adequate security. In the present case, the examinations helped--already in a preliminary stage of the investigations--to prevent the authorities from more expensive proceedings as well as the respective nursing home from being unjustly suspected of having committed a criminal offense.

Aged↗