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Biomedical subjects

H Weicker

Publications and source records attributed to H Weicker.

At least 55 records · Page 3Linked to original sources
PubMed1988

Humoral regulation of the orthostatic reaction.

A tilt-table test was performed on 12 untrained subjects to evaluate the humoral adaptation to postural change. The observed peripheral reaction with a reversible short-term rise of norepinephrine (NE) and plasma renin activity (PRA) allowed us to divide the syndrome of the orthostatic dysregulation into a hyponoradrenergic and hypernoradrenergic type. This classification can be helpful for the clinical evaluation and therapy of orthostatic lability. The central excessive stimulation of the antidiuretic (ADH) and adrenocorticotropic hormone (ACTH) follow-ing orthostatic symptoms such as weakness or dizziness was not completely reversible within the observation period of 30 min. The ADH and ACTH increase was not different between the hypo- and the hypernoradrenergic type of dysregulation but was the most sensitive indicator of orthostatic lability: 41% of all subjects showed a hypernoradrenergic orthostatic dysregulation with pronounced NE response and alpha 2-adrenoceptor down-regulation. By use of antiembolism stockings (AES) or dihydroergotamine (DHE) this rate decreased to 16%. This was associated with a significantly reduced NE and PRA response and a diminished alpha 2-adrenoceptor number.

Adrenocorticotropic Hormone↗
PubMed1988

Effects of temperature and water immersion on plasma catecholamines and circulation.

The effects of environmental air temperature of 6 degrees C and 26 degrees C on catecholamines (CA) and circulation were studied in eight male subjects during rest and during bicycle exercise at WOBLA for 45 min each. We found that resting at 6 degrees C increased the norepinephrine (NE) levels to the same levels as endurance exercises at 6 degrees C. The increase of CA levels was 2.5 to 3 times higher during work at 26 degrees C compared with 6 degrees C. During both rest and exercise at 6 degrees C we found a higher stroke volume of the heart and a reduced heart rate (HR) with no or only small effects on the oxygen uptake and blood lactate levels compared with 26 degrees C. Measurements of the skin temperatures showed large differences both at rest and during work; those of core temperature showed no changes at rest and a slightly more pronounced increase during work at 26 degrees C compared with 6 degrees C. The behavior of CA, plasma renin activity (PRA), plasma aldosterone (PA), and circulation were studied in 13 top class swimmers and 12 recreational swimmers during immersion into water of 27 degrees C for 10 min. The recreational swimmers were additionally immersed into water of 21 degrees C and 33 degrees C. Even immersion at 33 degrees C induced a small but significant increase of NE levels and of blood pressure (BP) values with no effect on the HR and blood lactate values. Epinephrine (EPI) showed a tendency to decrease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Differences in sympathoadrenal, hormonal, and metabolic adaptation to submaximal and maximal arm and leg work compared with whole stroke in breast-style swimming.

During work on land adaptational reactions of circulation and hormones are influenced by the body position, the activated muscle mass, and the working extremities. The aim of this study was to explore the additional effect of water immersion during swimming on cardiocirculatory, metabolic, and hormonal regulation under different working conditions. Twelve young men not specifically trained in swimming underwent swimming tests on 3 different days. They had to swim breast stroke in total as well as isolated with legs or arms only each for 10 min at submaximal intensity and 150 m or 100 m at maximal intensity. This study was focused on changes of catecholamines (CA), heart rate (HR), blood pressure (BP), glucose, lactate, plasma renin activity (PRA), and plasma aldosterone (PA). Additionally, parameters of the electrolyte-volume homeostasis were investigated. Norepinephrine (NE) and epinephrine (EPI) increased during swimming under submaximal and maximal conditions. The augmentation of CA and HR was the highest after swimming whole stroke and the lowest after swimming arm stroke only. They were related to intensity within one type of swimming and showed a dependence on muscle mass independent from lactate or glucose levels when the different types of swimming were compared, although a positive correlation between CA and lactate levels was found. The BP was higher after leg work than after arm work, contrary to observations done on land regarding the comparable submaximal work loads. We suppose that this is an effect of water immersion and the horizontal body position whereby the central hemodynamic circulation becomes stabilized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1988

Influence of exercise in water on hormonal, metabolic and adrenergic receptor changes in man.

We investigated hormonal, metabolic, and cardiovascular adaptations as well as changes of alpha 2- and beta 2-adrenergic receptors in response to three different exercise performances in water: 1000 m fin swimming with or without a neoprene suit and, additionally, 600 m diving with a breathing apparatus while performing several tasks. Eight male divers participated in the study. Blood samples were taken at rest on land, 10 min after water immersion, immediately after exercise, and after 20 min recovery. Both free and sulfoconjugated norepinephrine (NE) increased exercise-dependently. Moreover, heat loss in water caused elevation of plasma free NE. Free epinephrine (EPI) increases showed a highly significant correlation with NE except during fin swimming with a neoprene suit where EPI concentrations were constantly higher. ACTH and cortisol levels rose during exercise and paralleled those of plasma NE. Plasma aldosterone decreased in response to water immersion at rest. Blood volume regulating hormones such as plasma renin, aldosterone, and vasopressin were significantly higher during physical exercise. Moreover, increased pressure conditions during diving caused significantly higher secretion rates of all of these hormones, resulting in a higher systolic blood pressure. This clinical issue might be considered when examining diving ability. Lipolysis was elevated to the same degree after the three exercise schedules had been applied. As expected, plasma glucose also increased during physical activity. The lactate values observed after fin swimming, but not after diving with a breathing apparatus were closely related to NE. The lowest lactate levels were obtained during air-assisted diving.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1988

Sympathoadrenergic regulation of metabolism and cardiocirculation during and following running exercises of different intensity and duration.

In three different field studies running loads of 2 X 200 m and 400 m, 3 X 1000 m and 3000 m, and finally 10,000 m were performed by respective groups of sprinters, middle-, and long-distance runners. We investigated the effects of exercise on the sympathoadrenal system by determining catecholamine (CA) concentrations in the venous blood and urine [free norepinephrine (NE), epinephrine (EPI)] and the respective sulfoconjugates in plasma and various hormonal, metabolic, and cardiocirculatory parameters. Endurance-trained athletes showed a lower heart rate (HR) and plasma renin activity (PRA) at rest in comparison with the sprinters. The concentrations of the plasma CA reflected the intensity more than the duration of exercise. At rest and following recovery the ratio of free NE/EPI in plasma was markedly higher in the group of sprinters in comparison with the long-distance runners. During exercise, however, an opposite movement occurred resulting in a higher ratio in the latter group. The pre-start ratios of NE/EPI in urine were similar to those in plasma. The sports disciplines' specific differences in NE/EPI both at rest and during exercise suggest that the overall sympathetic activity, reflected by NE and EPI, is regulated in a quite differentiated pattern. The sulfoconjugated CA, however, increased less clearly after the middle- and long-distance bouts than the respective free CA which caused the ratio sulfates/free CA to decline. There were strong relations between the levels of free plasma NE and EPI and that of blood lactate which, however, rather reflects a parallelism subsequent to the highly intensive stimulation.

Adaptation, Physiological↗
PubMed1988

Sympathoadrenergic regulation in elite fencers in training and competition.

In ten fencers at the top national level the adrenergic regulation was investigated by determining the free and sulfoconjugated catecholamines (CA) in a training fight and a competition for the national championship to evaluate the influence of emotional strain in this discipline. In the training fight which is physically more strenuous, norepinephrine (NE) was significantly higher (+27%) than in the championship contest after which the epinephrine (EPI) level was more increased (+76.5%). Accordingly, the systolic blood pressure (SBP) was higher during competition and correlated with EPI. The share of the sulfated CA in their total amount was reduced in both loads. Since energy production in fencing is predominantly alactacitic during maximal loads of short duration and aerobic during submaximal load intensities, the lactate level in the training fight was below the anaerobic/aerobic threshold. The significantly higher lactate, glucose, and alanine levels during the fight for the national championship, presumably induced by the additional stimulation of the anaerobic muscular and hepatic glycogenolysis as well as muscular glycolysis, may be accounted to the fortified EPI secretion caused by emotional strain. The higher cortisol and renin levels may be explained by the strong central stimulation and the direct peripheral effect of EPI respectively.

Adult↗
PubMed1988

Influence of different experimental recreation treatments on sympathoadrenergic and metabolic regulation mechanisms in repeated exercises.

The influence of different recreation treatments on the sympathoadrenergic regulation, heart rate, mean blood pressure, plasma lactate, and glucose levels was investigated in a study in which the 1000 m distance was performed twice by top middle- and long-distance runners. Between the two runs, executed three times in an interval of 1 week, different regeneration strategies such as active or passive recreation as well as progressive muscle relaxation (PMR) with cognitive skill (Cl) were applied. The best running times in the second run were achieved after the PMR with Cl. After this treatment heart rate (HR) and mean arterial blood pressure (MBP) were not higher than in the other forms of regeneration, although the norepinephrine (NE) and epinephrine (EPI) increase was significantly higher after the second run compared with other treatments. The lactate and glucose levels in plasma were significantly higher after PMR with Cl than after active and passive regeneration. After the recovery period both metabolites decreased faster after PMR with Cl. The percentage of catecholamine sulfates of the total amount decreased after the first and the second run without significant differences between the three recreation treatments.

Blood Glucose↗
PubMed1987

Sulfoconjugated catecholamines: lack of beta-adrenoceptor binding and adenylate cyclase stimulation in human mononuclear leukocytes.

The racemic 3-O-sulfates of epinephrine and norepinephrine as well as 4-O-sulfoconjugated dopamine were synthesized, highly purified and investigated with respect to their beta-adrenoceptor affinities and relative potencies in the receptor-coupled adenylate cyclase system in isolated human mononuclear leukocytes. The receptor affinities of all catecholamine sulfates were reduced at least 1,000-fold when compared to those of the free catecholamines. Furthermore, catecholamine sulfoconjugates did not produce intracellular cAMP signals. In contrast to the sulfated catecholamine metabolites, the 3-O-methylated catecholamines metanephrine and normetanephrine were found to behave as endogenous beta-adrenoceptor-competing agents with lower beta-receptor affinities than the corresponding free catecholamines. No beta-receptor agonist activity in the adenylate cyclase system was found with metanephrine and normetanephrine. Our data provide direct evidence that sulfoconjugation renders catecholamines inactive as beta-receptor ligands and must thus be regarded as a mechanism to control adrenergic action at the prereceptor level by a buffering of the concentration of free catecholamines. The physiological significance of a potential role of 3-O-methylated catecholamines as endogenous beta-receptor antagonists has to be further clarified.

Adenylyl Cyclases↗
PubMed1987

Clinical and metabolic effects of gestodene and levonorgestrel.

The new low-dose combination oral contraceptive (OC) containing 75 micrograms of the new progestogen gestodene (GTD) plus 30 micrograms ethinyl estradiol (EE) was clinically tested and compared with a levonorgestrel (LNG) combined pill (150 micrograms LNG plus 30 micrograms EE). In a randomized clinical comparative study (A), 176 women were treated with the GTD-containing pill and 185 with the LNG-containing pill for six cycles. This study was followed by a second multicenter study (B) covering 707 patients taking the GTD-containing pill for up to 24 cycles (total, 9,947 cycles). In a third study (C), metabolic effects were assessed using a randomly organized baseline control trial (pretreatment/treatment cycles); 30 patients received the GTD-containing pill and 30 received the LNG-containing pill. Carbohydrate metabolism, lipid metabolism, and blood clotting were investigated, and an interim analysis was performed after six OC cycles. No pregnancies and no severe side effects occurred in any of the studies. Intermenstrual bleeding decreased as usual during treatment. In the total number of gestodene cycles in studies A and B, there was a 6.9% incidence of spotting, a 0.8% incidence of breakthrough bleeding, and a 0.7% incidence of both spotting and breakthrough bleeding in studies A and B patients taking gestodene. Amenorrhea occurred in 0.6% of cycles. Body weight remained unchanged (+/- 2 kg) after 24 cycles in 80.5% of study B patients taking gestodene. Blood pressure remained normal in about 95% of all study B patients; a normalization was observed in greater than 60% of patients with previously elevated blood pressure. No clinically relevant changes in carbohydrate metabolism, lipid metabolism, or blood clotting were observed in study C. The new GTD-containing low-dose combination pill proved to be a safe and reliable contraceptive agent.

Adolescent↗
PubMed1986

[Physiologic variability of plasma catecholamines].

In an earlier publication, we described a modified procedure for the determination of plasma catecholamine levels using high-performance liquid chromatography (HPLC), followed by amperometry. In this paper, we present our results on the variability of normal catecholamine values in plasma for noradrenaline (NA), adrenaline (A) and dopamine (DA). In 122 women and men at rest, the range for NA was 0.15-3.5 nmol/l, for A 0.01-0.8 nmol/l and for DA 0.04-4.5 nmol/l. We also describe the effects of orthostasis, intravenous catheters, food intake, cigarette smoking, age and sex on venous catecholamine levels. The efficiency of the HPLC method allowed us to check, using a large subject group, the results obtained by other authors from studies involving smaller subject groups with more expensive and time-consuming methods.

Adult↗
PubMed1986

Lipid, carbohydrate, and androgen metabolism in women using a triphasic oral contraceptive containing norethindrone for one year.

A clinical trial was conducted to determine the effects of a norethindrone-containing triphasic oral contraceptive, Ortho-Novum 7/7/7, on lipid, carbohydrate, and androgen metabolism in 22 women during 12 cycles of use. Examinations were made in two consecutive cycles before treatment and after 3, 6, 9, and 12 cycles of treatment. Treatment consisted of ethinyl estradiol, 35 micrograms/d for 21 days, together with norethindrone in stepwise-increasing doses of 0.5, 0.75, and 1.0 mg/d, with each dose given for seven days. Only a minimal impact on lipid metabolism was observed during treatment. There were no unfavorable changes in any HDL-related measurement. HDL-cholesterol and alpha levels were not altered in any cycle. The HDL:LDL ratio was not significantly altered during treatment. LDL cholesterol levels were also unaltered during treatment, but there were slight elevations in other LDL-related measurements in some cycles. Total cholesterol, phospholipid, and triglyceride levels were elevated in cycle 9, and triglyceride levels also increased in cycle 3, but no significant changes were observed in these levels at any other sampling times. Carbohydrate metabolism did not change significantly as indicated by mean fasting levels of glucose, insulin, and HbA1c or by levels of these parameters after a glucose load. Changes observed in androgenic parameters indicate the lack of androgenicity. The results of this study demonstrate that Ortho-Novum 7/7/7 use results in a minimal impact on lipid metabolism, no change in carbohydrate metabolism, and no potential for androgenic side effects.

Adult↗
PubMed1985

Effects of training and methandrostenolone (an anabolic steroid) on energy metabolism in the guinea pig: changes in enzyme activities in gastrocnemius muscle and myocardium.

Modifications of enzyme activities (creatine kinase and its B subunit; adenylate kinase; hexokinase; phosphofructokinase; lactate dehydrogenase; malate dehydrogenase, isocitrate dehydrogenase; citrate synthase; acetylcarnitine transferase; beta-hydroxyacetyl-CoA dehydrogenase; cytochrome c oxidase) in gastrocnemius muscle and myocardium were reported after two forms of training with or without administration of anabolic steroid. Endurance training was on a horizontal motor-driven treadmill, 2 km X hr-1, 5 days a week for 0.5 hr per day for 5 weeks. In the case of power endurance training there was a slope of 45 degrees. Enzyme activities in controls and treated guinea pigs, as well as treatment-induced enzyme activity changes are time dependent. Some of these activities correlate linearly with one another; such correlations characterize the effect of adaptation. Endurance training and power endurance training in this study induce similar modifications and seem to differ essentially in the daily work load. The anabolic steroid methandrostenolone (dianabol) induces modifications which training does not bring about but which training at least partially eliminates.

Animals↗
PubMed1985

[Effects of continuous body stress and methandienone on the degradation of myofibrillar proteins in the guinea pig heart and soleus muscle].

The influence of permanent physical stress (running training) and of the application of an anabole-androgenic steroid, 17-beta-hydroxy-17-methylandrosta-1,4-dien-3-on (metandienone, Dianabol) on the degradation rate of myofibrillar proteins of heart and soleus of male guinea-pigs was investigated. The rate of protein degradation was measured by the time-dependent loss of radioactive proteins after labelling with 14C-leucine in vivo. The investigations led to the following results: We found no significant change of the body or muscle weights of any of the guinea-pig groups examined. Only the combination of physical stress with metandienone showed a significant increase of the myofibrillar protein concentration as well as an increase of the specific activity of the myofibrillar proteins of heart and soleus. These findings could be the result of a decreased degradation rate of the myofibrillar proteins. The myofibrillar proteins of the heart were higher labelled than the myofibrillar proteins of the soleus. The concentration of myofibrillar proteins was higher in the soleus than in the heart. The 14C-leucine activity of the free amino acid pool was significantly higher in the heart than in the soleus in the first minutes after labelling.

Amino Acids↗