A method using body surface potential maps for assessment of myocardium lesions with changed repolarization is presented and suitable mapping system is introduced. Differences between normal and altered QRST integral maps together with torso volume conductor model were used to determine the equivalent dipole representing the lesion. Performance of the method was studied on simulated data. Changed repolarization was modeled by shortening of myocyte action potentials in regions typical for stenosis of the main coronary arteries. The equivalent dipole estimated the positions of small lesions with a mean error of 9±4 mm (17±14 mm for larger transmural lesions). The subepicardial or subendocardial character of the lesions was reflected in the dipole orientation. Tests of the method on patients after myocardial infarction that underwent coronary intervention on a single coronary vessel showed that in 7 of 8 successfully treated patients the dipole position matched well with the treated vessel. A small dipole moment in another patient indicated unsuccessful treatment. The method was implemented in a new 128-channel mapping system. Its active electrodes, battery powered measuring unit and optical computer interface help to minimize noise in ECG and guarantee patient´s safety. The results suggest that the method and mapping system offer useful tools for noninvasive identification of local repolarization changes in the myocardium., M. Tyšler, P. Kneppo, M. Turzová, J. Švehlíková, S. Karas, E. Hebláková, K. Hána, S. Filipová., and Obsahuje bibliografii
Portal-systemic shunting is an important circulatory abnormality in patients with liver cirrhosis. Glyceryl trinitrate (GTN) that is normally subject to first pass elimination, may exhibit higher bioavailability in these patients. This study compares the pharmacodynamic effects of GTN after peroral and sublingual administration for noninvasive assessment of shunting. Six control subjects and 15 patients with cirrhosis were studied after oral and sublingual application of 0.5 mg of GTN. Liver cirrhosis was complicated by portal hypertension in 7 of the patients and 4 patients had surgically implanted portocaval anastomosis. Digital plethysmography, which is highly sensitive and is essentially noninvasive in nature, was used to assess and compare the pharmacodynamic effects of GTN. The following values of the ratio of areas under the pharmacodynamic effects/time curve were obtained: 0.08±0.06 in healthy subjects, 0.52±0.21 in patients with uncomplicated cirrhosis, 0.99±0.34 in patients with portal hypertension and 1.24±0.43 in patients with portal-systemic shunts. We conclude that increased bioavailability of GTN reflects portal-systemic shunting and might be used providing that the pharmacodynamic data reflect both pharmacokinetic variability and the pharmacokinetic-pharmacodynamic interrelations., O. Slanař, J. Aubrecht, F. Perlík., and Obsahuje bibliografii
Excessive production of reactive oxygen species (ROS) are implicated in the pathogenesis of numerous disease states. However, direct measurement of in vivo ROS in humans has remained elusive due to limited access to appropriate tissue beds and the inherently short half-lives and high reactivity of ROS. Herein, we describe a novel technique by which to measure in vivo ROS in human skeletal muscle. Microdialysis probes were inserted into the vastus lateralis of eight healthy volunteers. Amplex Ultrared, a highly specific fluorogenic substrate for hydrogen peroxide (H2O2), and horseradish peroxidase (HRP), were perfused through microdialysis probes, and outflowing dialysate was collected and fluorescence was measured. Extracellular H2O2 that crossed the microdialysis membrane was measured via fluorescence of the dialysate. Superoxide dismutase (SOD) was then added to the inflowing perfusion media to convert any superoxide crossing the microdialysis membrane to H2O2 within the microdialysis probe. Fluorescence significantly increased (P=0.005) upon SOD addition. These data demonstrate the feasibility of measuring both in vivo H2O2 and superoxide in the extracellular environment of human skeletal muscle, providing a technique with a potential application to a wide range of circulatory and metabolic studies of oxidative stress., J. D. La Favor, E. J. Anderson, R. C. Hickner., and Obsahuje bibliografii
The oxidative stress plays an important role in the development of cardiovascular diseases (CVD). In CVD progression an aberrant redox regulation was observed. In this regulation levels of reactive oxygen species (ROS) play an important role in cellular signaling, where Nrf2 is the key regulator of redox homeostasis. Keap1-Nrf2-ARE system regulates a great set of detoxificant and antioxidant enzymes in cells after ROS and electrophiles exposure. In this review we focus on radical-generating systems in cardiovascular system as well as on Nrf2 as a target against oxidative stress and a key player of redox regulation in cardiovascular diseases. We also summarize the current knowledge about the role of Nrf2 in pathophysiology of several CVD (hypertension, cardiac hypertrophy, cardiomyopathies) as well as in cardioprotection against myocardial ischemia/ reperfusion injury., M. Barančík, L. Grešová, M. Barteková, I. Dovinová., and Obsahuje bibliografii
Associations between different infectious agents and obesity have been reported in humans for over thirty years. In many cases, as in nosocomial infections, this relationship reflects the greater susceptibility of obese individuals to infection due to impaired immunity. In such cases, the infection is not related to obesity as a causal factor but represents a complication of obesity. In contrast, several infections have been suggested as potential causal factors in human obesity. However, evidence of a causal linkage to human obesity has only been provided for adenovirus 36 (Adv36). This virus activates lipogenic and proinflammatory pathways in adipose tissue, improves insulin sensitivity, lipid profile and hepatic steatosis. The E4orf1 gene of Adv36 exerts insulin senzitizing effects, but is devoid of its pro-inflammatory modalities. The development of a vaccine to prevent Adv36- induced obesity or the use of E4orf1 as a ligand for novel antidiabetic drugs could open new horizons in the prophylaxis and treatment of obesity and diabetes. More experimental and clinical studies are needed to elucidate the mutual relations between infection and obesity, identify additional infectious agents causing human obesity, as well as define the conditions that predispose obese individuals to specific infections., V. Hainer, H. Zamrazilová, M. Kunešová, B. Bendlová, I. Aldhoon-Hainerová., and Obsahuje bibliografii
The functional antagonism between obestatin and ghrelin in the testis is under investigation. We investigated the ability of obestatin to counteract the inhibitory effect of ghrelin on basal and stimulated testosterone (T) secretion in vitro. Testicular strips from adult rats were incubated with 10 ng/ml and 100 ng /ml of obestatin alone, ghrelin alone and obestatin + ghrelin. Obestatin modulation of stimulated T secretion was evaluated by incubation of testicular samples with 10 ng/ml and 100 ng/ml obestatin, ghrelin and obestatin + ghrelin in the absence and presen ce of 10 IU of human chorionic gonadotrophin (hCG). T concentrations in the hCG treated groups were significantly (P<0.0001) higher than those in the control groups. Obestatin caused a significant increase in basal T secretion in a dose-dependent manner; however, obestatin at the both 10 ng /ml and 100 ng/ml significantly (P<0.0001) in creased hCG-stimulated T secretion. In contrast, ghrelin in a dose-dependent manner significantly (P<0.001) decreased both basal and hCG-induced T secretion by testicular slices. Obestatin opposed the inhibitory effect of ghrelin on T secretion under both basal and hCG-stimulated conditions at all doses tested. In conclusions, administration of obestatin was able to antagonize the inhibitory effect of ghrelin on testosterone secretion in vitro ., T. Afsar, S. Jahan, S. Razak, A. Almajwal, M. Abulmeaty, H. Wazir, A. Majeed., and Obsahuje bibliografii
The aim of the study was to assess the association between promoter polymorphism [A(-596)G] in interleukin-6 gene and office systolic and diastolic blood pressures, and the heart rate (HR) in apparently healthy Czech subjects. Furthermore, we evaluated the possible influence of gender, BMI and smoking on these supposed associations. An age-matched (40-50 years) and gender-matched (F/M=81/89) sample of apparently healthy Czech subjects (n=170, F/M=81/89) without hypertension, other cardiovascular diseases or diabetes was examined. The A(-596)G Il-6 gene polymorphism was detected by the PCR method. No differences in genotype distribution and/or allelic frequency was found between groups with lower systolic blood pressure (£ 122 mm Hg) and higher systolic blood pressure (> 122 mm Hg). Similarly, no differences in the IL-6 polymorphism were found between lower (£ 86 mm Hg) and higher (> 86 mm Hg) diastolic blood pressure groups. However, we proved a significant increase of genotypes AG+GG as well as the allele (-596)G in higher (>78 beats/min) heart rate group. The genotypes AG+GG represent significantly higher relative risk for higher HR frequency, especially in women. Among lean persons with a low heart rate frequency, fewer AG+GG genotypes were determined than among any other subjects. The genotypes AG+GG are more frequent in non-smoking persons with higher HR compared to non-smoking subjects with lower HR, especially in women. Gender, BMI and smoking substantially modify the distribution of A(-596)G Il-6 gene polymorphism in apparently healthy persons with lower or higher heart rate., A. Vašků, M. Souček, M. Goldbergová, J. Vácha., and Obsahuje bibliografii
Olfaction enables most mammalian species to detect and discriminate vast numbers of chemical structures called odorants and pheromones. The perception of such chemical compounds is mediated via two major olfactory systems, the main olfactory system and the vomeronasal system, as well as minor systems, such as the septal organ and the Grueneberg ganglion. Distinct differences exist not only among species but also among individuals in terms of their olfactory sensitivity; however, little is known about the mechanisms that determine these differences. In research on the olfactory sensitivity of mammals, scientists thus depend in most cases on behavioral testing. In this article, we reviewed scientific studies performed on various mammalian species using different methodologies and target chemical substances. Human and non-human primates as well as rodents and dogs are the most frequently studied species. Olfactory threshold studies on other species do not exist with the exception of domestic pigs. Olfactory testing performed on seals, elephants, and bats focused more on discriminative abilities than on sensitivity. An overview of olfactory sensitivity studies as well as olfactory detection ability in most studied mammalian species is presented here, focusing on comparable olfactory detection thresholds. The basics of olfactory perception and olfactory sensitivity factors are also described., M. Wackermannová, L. Pinc, L. Jebavý., and Obsahuje bibliografii
Omega-3 fatty acids (Ω3FA) are known to reduce hypertriglyceridemia- and inflammation-induced vascular wall diseases. However, mechanisms of their effects are not completely clear. We examined, whether 10-day Ω3FA diet can reduce bacterial lipopolysaccharide-induced changes in expression of gap junction protein connexin40 (Cx40) in the aorta of hereditary hypertriglyceridemic (hHTG) rats. After administration of a single dose of lipopolysaccharide (LPS, 1 mg/kg, i.p.) to adult hHTG rats, animals were fed with Ω3FA diet (30 mg/kg/day) for 10 days. LPS decreased Cx40 expression that was associated with reduced acetylcholine-induced relaxation of aorta. Ω3FA administration to LPS rats had partial anti-inflammatory effects, associated with increased Cx40 expression and improved endothelium dependent relaxation of the aorta. Our results suggest that 10-day Ω3FA diet could protect endothelium-dependent relaxation of the aorta of hHTG rats against LPS-induced damage through the modulation of endothelial Cx40 expression, K. Frimmel, R. Sotníková, J. Navarová, I. Bernátová, J. Križák, Z. Haviarová, B. Kura, J. Slezák, Ľ. Okruhlicová., and Obsahuje bibliografii