The extent to which sex differences in cardiac function may be attributed to the direct myocardial influence of testosterone is unclear. In this study the effects of gonadal testosterone withdrawal (GDX) and replacement (GDX+T) in rats, on cardiomyocyte shortening and intracellular Ca2+ handling was investigated (0.5 Hz, 25 oC). At all extracellular [Ca2+] tested (0.5-2.0 mM), the Ca2+ transient amplitude was significantly reduced (by ~ 50 %) in myocytes of GDX rats two weeks post- gonadectomy. The time course of Ca2+ transient decay was significantly prolonged in GDX myocytes (tau, 455±80 ms) compared with intact (279±23 ms) and GDX+T (277±19 ms). Maximum shortening of GDX myocytes was markedly reduced (by more than 60 %) and relaxation significantly delayed (by more than 35 %) compared with intact and GDX+T groups. Thus testosterone replacement completely reversed the cardiomyocyte hypocontractility induced by gonadectomy. These results provide direct evidence for a role of testosterone in regulating functional Ca2+ handling and contractility in the heart., C. L. Curl ... [et al.]., and Obsahuje seznam literatury
The activity of antioxidant enzymes, copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and catalase (CAT), as well as that of the mitochondrial FAD-dependent a-glycerophosphate dehydrogenase (a-GPD) in the rat interscapular brown adipose tissue (IBAT) were studied after the treatment with methimazole (MMI) for three weeks or with iopanoic acid (IOP) for five days. Besides, the mitochondrial concentration of uncoupling protein-1 (UCP-1) and the activity of catecholamine degrading enzyme monoamine oxidase (MAO) in the IBAT as well as the activity of the catecholamine synthesizing enzyme, dopamine b-hydroxylase (DBH) in rat serum were examined. Judging by the significantly enhanced level of serum DBH, which is an index of sympathetic activity, and that of IBAT MAO, the increase in MnSOD and CAT activities in the IBAT of hypothyroid (MMI-treated) rats seems to be due to elevated activity of sympathetic nervous system (SNS). However, CuZnSOD activity is not affected by SNS. On the contrary, IOP, which is a potent inhibitor of T4 deiodination into T3 producing "local" hypothyroidism, did not change either SNS activity or activities of IBAT antioxidant enzyme. However, both treatments significantly decreased IBAT UCP-1 content and a-GPD activity suggesting that the optimal T3 concentration in the IBAT is necessary for maintaining basal levels of these key mitochondrial parameters., N. Petrović, G. Cvijić V. Davidović., and Obsahuje bibliografii
We investigated the association between metamphetamine dependence and TaqI A polymorphism of the dopamine receptor D2 gene (DRD2), I/D polymorphism in angiotensin-converting enzyme (ACE) and M235T polymorphism of the angiotensinogen gene (AGT) in 93 unrelated metamphetamine-dependent subjects and 131 controls. Our results did not prove any association of TaqI A polymorphism of the DRD2 gene, I/D polymorphism of ACE gene, and M235T polymorphism of AGT gene with the metamphetamine dependence in Caucasians of Czech origin. However, a significant difference in allele I frequency between male and female control groups for the I/D ACE polymorphism (p<0.03) was found., O. Šerý, V. Vojtová, P. Zvolský., and Obsahuje bibliografii
We tested whether seal location at iliac crest (IC) or upper abdomen (UA), before and during lower body negative pressure (LBNP), would affect thoracic electrical impedance, hepatic blood flow, and central cardiovascular responses to LBNP. After 30 min of supine rest, LBNP at -40 mmHg was applied for 15 min, either at IC or UA, in 14 healthy males. Plasma density and indocyanine green concentrations assessed plasma volume changes and hepatic perfusion. With both sealing types, LBNP-induced effects remained unchanged for mean arterial pressure (-3.0±1.1 mm Hg), cardiac output (-1.0 l min-1), and plasma volume (-11 %). Heart rate was greater during UA (80.6±3.3 bpm) than IC (76.0±2.5 bpm) (p<0.01) and thoracic impedance increased more using UA (3.2±0.2 Ω) than IC (1.8±0.2 Ω) (p<0.0001). Furthermore, during supine rest, UA was accompanied by lower thoracic impedance (26.9±1.1 vs 29.0±0.8 Ω , p<0.001) and hepatic perfusion (1.6 vs 1.8 l.min-1, p<0.05) compared to IC. The data suggest that the reduction in central blood volume in response to LBNP depends on location of the applied seal. The sealing in itself altered blood volume distribution and hepatic perfusion in supine resting humans. Finally, application of LBNP with the seal at the upper abdomen induced a markedly larger reduction in central blood volume and greater increases in heart rate than when the seal was located at the iliac crest., N. Goswami ... [et al.]., and Obsahuje seznam literatury
The aim of this study was to follow up whether the modification of pro-antioxidant status by oral thiol administration such as N- acetylcysteine and α-lipoic acid affects the hematological response. Twenty-eight healthy men participated in two independent experiments. Subjects were randomly assigned to one of four groups: controls (CNAC and CALA ), N-acetylcysteine (NAC) and α-lipoic acid (ALA). 1200 mg of N-acetylcysteine, 600 mg of α-lipoic acid or placebo were administered for 8 days in two doses. NAC or ALA administration significantly elevated plasma total antioxidant stat us (TAS) and reduced protein carbonylation (PC) and lipid peroxidation (TBARS) by more than 30 %. The reduced glutathione (GSH) and hematological parameters changed only in response to NAC administration. NAC significantly elevated the level of GSH (+33 %), EPO (+26 %), Hb (+9 %) and Hct (+9 %) compared with CNAC. The mean corpuscular volume (MCV) and the mean corpuscular hemoglobin (MCH) also increased by more than 12 % after NAC. The numerous negative or positive correlations between the measures of TAS, PC, TBARS and hematological parameters were found, which suggest the NAC-induced interaction between pro-antioxidant and hematological values. Our study has shown that both N-acetylcysteine and α-lipoic acid intake reveal an antioxidant action, but only N-acetylcysteine improves the haematological response., A. Zembron-Lacny ... [et al.]., and Obsahuje seznam literatury
Sudden death is a possible occurrence for newborns younger than 1 year with severe aortic coarctation (CoA) before surgical correction. In our previous study, we showed a significant increase of QTc-D and JTc-D in newborns with isolated severe aortic coarctation, electrocardiog raphic parameters that clinical and experimental studies have suggested could reflect the physiological variability of regional and ventricular repolarization and could provide a substrate for life-threatening ventricular arrhythmias. The aim of the current study was to evaluate the effect of surgical repair of CoA on QTc-d, JTc-d in severe aortic coarctation newborns with no associated congenital cardiac malformations. The study included 30 newborns (18M; 70±12 h old) affected by severe congenit al aortic coarct ation, without associated cardiac malformation s. All newborns underwent to classic extended end-to-end repair. Echocardiographic and electrocardiographic measurements were performed in each patient 24 h before and 24 h afte r the interventional procedure and at the end of the follow-up period, 1 month after the surgical correction. All patients at baseline, 24 h and one month after CoA surgical repair did not significantly differ in terms of heart rate, weight, height, and echocardiographic parameters. There were no statistically significant differences in QTc-D (111.7±47.4 vs 111.9±63.8 ms vs 108.5±55.4 ms; P =0.4) and JTc-D (98.1±41.3 vs 111.4±47.5 vs 105.1±33.4 ms; P =0.3) before, 24 h and 1 month after CoA surgical correction. In conclusions, our study did not show a statistically signif icant decrease in QTc-D and JTc- D, suggesting the hypothesis that the acute left ventricular afterload reduction, related to successful CoA surgical correction, may not reduce the ventricular electrical instability in the short- term follow-up., G. Nigro ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Two different isolated skeletal muscles of Japanese quail were used. The influence of branched chain amino acids on the fractional rate of protein synthesis (FSR) was evaluated using 14C-tyrosine. The addition of 0.5 mM valine, leucine or isoleucine to the incubation medium significantly decreased (P<0.05) the value of FSR in extensor metacarpalis radialis. In the ambiens muscle only the application of leucine increased the FSR significantly while valine and isoleucine were without any effect., J. Antalíková, J. Jankela, M. Baranovská., and Obsahuje bibliografii
Increased and prolonged postprandial lipemia has been identified as a risk factor of cardiovascular disease. However, there is no consensus on how to test postprandial lipemia, especia lly with respect to the composition of an experimental meal. To address this question of how glucose, when added to a fat load, affects the selected parameters of postprandial lipemia, we carried out a study in 30 healthy male volunteers. Men consumed an experimental meal containing either 75 g of fat + 25 g of glucose (F+G meal) or 75 g of fat (F meal) in a control experiment. Blood was taken before the meal and at selected time points within the following 8 h. Glucose, when added to a fat load, induced an increase of glycemia and insulinemia and, surprisingly, a 20 % reduction in the response of both total and active glucagon -like peptide -1 (GLP -1) concentration. The addition of glucose did not affect the magnitude of postprandial triglyceridemia and TRL -C and TRL -TG concentrations but stimulated a faster response of chylomicrons to the test meal, evaluated by changes in apolipoprotein B -48 concentrations. The addition of glucose induced the physiological response of insulin and the lower response of GLP -1 to the test meal during the early postprandial phase, but had no effect on changes of TRL -cholesterol and TRL -TG within 8 h after the meal., K. Zemánková, J. Mrázková, J. Piťha, J. Kovář., and Obsahuje bibliografii
Experiments were conducted to study the effect of goldthioglucose (GTG) upon the processes associated with lipid peroxidation. The glucose-6-phosphate dehydrogenase activity (G6PD; E.C.1.1.1.49) in red blood cells (RBC) and the amount of malonaldehyde precursors (MDA) per gram of brain, liver and kidney were determined. Adult mice received i.p. injections for three consecutive days of either saline (controls) or GTG dissolved in saline, in a dose of 0.10 mg.g-1 or 0.15 mg.g-1 b.w. In mice receiving higher dose of GTG the G6PD activity was significantly increased (349.38± 17.46 mU.10-9 RBC compared to 258.2± 14.46 mU.10-9 RBC in control animals). The content of MDA precursors rose significantly from 4.8± 0.81 m mol.g-1 of the liver in controls to 8.12± 1.41 m mol.g -1 and 7.88± 0.51 m mol.g-1 and from 18.71± 1.01 m mol.g-1 of the kidneys in controls to 24.25± 1.25 m mol.g-1 and 24.88± 1.7 m mol.g-1 respectively. The GTG-induced higher levels of MDA precursors and increased G6PD activity in RBC corresponds to the rise in lipid peroxidation and its participation in producing the lesions after experimental and therapeutic use of gold-containing substances seems possible., D. Košťová, E. Michnová., and Obsahuje bibliografii