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Biomedical subjects

V Brodan

Publications and source records attributed to V Brodan.

At least 37 records · Page 2Linked to original sources
PubMed1982

Changes in the circadian rhythm of serum iron induced by a 5-day sleep deprivation.

The effect of 5 days of sleep deprivation on the circadian rhythm of serum iron was studied in a group of six healthy male volunteers. The results were compared with a control group of five individuals, whose normal sleep cycle was preserved, but whose daily regimen was otherwise identical with the sleep deprivation group. Their biorhythm was processed mathematically using cosinor analysis. Sleep deprivation markedly reduced the mean level of iron, diminished the absolute and relative amplitude of oscillations, disturbed the shape of the daily course of serum iron and gradually decreased the computative acrophase, i.e., shortened the period of rhythm. Forty-eight hours of recovery resulted only in a partial normalization of all the observed changes. The potential mechanisms of the observed changes are discussed.

Adult↗
PubMed1982

Activities of muscle energy supplying enzymes after 5 days complete fasting in young men.

The effect of 5 days' complete fasting on the activity of 7 enzymes of energy supplying metabolism was studied in the vastus lateralis muscles of 9 healthy male volunteers. There was a significant decrease of lactate dehydrogenase (by 66%), triosephosphate dehydrogenase (by 61%), malate:NAD dehydrogenase (by 48%), hexokinase (by 40%), 3-hydroxyacyl-CoA-dehydrogenase (by 40%), triosephosphate dehydrogenase/3-hydroxyacyl-CoA-dehydrogenase (by 35%), citrate synthase (by 33%). Glycerolphosphate:NAD dehydrogenase activity did not decrease significantly. These findings suggest a) that utilization of the major energy substrates decreases; b) that the decrease mainly concerns the catabolism of carbohydrates, that of fatty acids to a lesser extent; c) that the decreased capacity of carbohydrate catabolism is partly compensated for by the predominance of the more economic aerobic-oxidative pathway; d) that the reducing equivalents formed in the cytosol may be transported via the glycerolphosphate shuttle into the respiratory chain to a greater extent, so that a greater portion is not lost by the reduction of pyruvate to lactate.

Adult↗
PubMed1982

The effect of stress on circadian rhythms.

The authors chose four types of intensive stress in man and show their effect on the circadian rhythms of selected parameters. Sleep deprivation reduces mean sideraemia and oscilation amplitudes. The morning rhythm maximum shifts to early morning hours. Acute fasting does not change the biorhythm of serum iron despite that mean sideraemia increases. On the other hand, realimentation is associated with a marked drop of iron level and a shift of the morning maximum to early afternoon hours. Stress induced by isolation in humid warm environment initiates a decrease of systolic blood pressure. While biorhythm amplitude remains unchanged peak systolic pressure moves from the usual 18 to 20 hours up to 23 to 24 hours. Stress caused by diagnostic cardiac catheterization results in biorhythm inversion of the urinary excretion of catecholamines and 17-OH-corticoids. On the day of catheterization, performed in all cases in the morning hours, the usual morning peak values of adrenaline shifted to afternoon hours and those of noradrenaline and 17-OH-corticoids even to late night hours. For practical purposes, biorhythm changes can be used as indicators of the effect and intensity of stress.

17-Hydroxycorticosteroids↗
PubMed1982

The effect of glucagon on myocardial metabolism in diagnostic cardiac pacing.

Nine patients with the angina pectoris syndrome in the absence of a history of demonstrable myocardial infarction were examined twice at rest and during cardiac pacing at 13-min intervals. Glucagon (0.5 mg/50 ml saline) was applied before the second examination. The authors investigated the differences of lactate (La) and lactate-pyruvate ratio (La:Py) between arterial blood and coronary sinus (a-cs diff) and the values of serum transaminases and glycaemia. A negative La and/or La:Py a-cs diff during or after pacing was interpreted as a positive qualitative sign of induced acute myocardial ischaemia. Application of glucagon on the second cardiac pacing led to worsening of the metabolic situation in 71% of patients; none of the patients showed improvement. The La:Py a-cs diff after glucagon was negative in all patients.

Adult↗
PubMed1981

Effects of sleep deprivation on the activity of selected metabolic enzymes in skeletal muscle.

The effect of 120-h sleep deprivation on the activity of selected enzymes of energy metabolism in skeletal muscle was studied in seven healthy volunteers. The results showed a significant decrease in the activity of malate dehydrogenase, citrate synthase, glycerol-3-phosphate dehydrogenase and lactate dehydrogenase. Triosephosphate dehydrogenase, hexokinase, and hydroxyacyl-CoA-dehydrogenase activities showed an insignificant decrease. The findings are indicative of (1) decreased aerobic oxidation capacity; (2) reduced function of reducing-equivalent carriers from cytosol across the mitochondrial membrane; (3) relative accentuation of the non-aerobic glycolytic pathway; (4) a prediabetic type of muscle metabolism.

3-Hydroxyacyl CoA Dehydrogenases↗