An epileptic seizure and postictal period in addition to well-known features are also characterize d by massive consumption of energy. This is thought to lead to oxidative stress and increased generation of free radicals, which is reflected by increased levels of oxidative products. Our previous work described the neuroprotective effects of melatonin in preventing cognitive worsening after a single epileptic seizure. This work was aimed on direct measurement of free radicals in brain tissue using the EPR method 1, 15 and 60 minutes after seizure. The measurement was performed in adult male Wistar rats at the mentioned intervals after a single tonic-clonic seizure induced by flurothyl. In comparison to control animals there was a significant increase in hydroxyl and nitroxyl radicals 60 minutes after the seizure. The levels of hydroxyl radicals were significantly lower in animals that received melatonin 60 minutes before seizure induction compared to animals without preventive treatment. Therefore, melatonin affected th e generation of the measured free radicals differently. An important finding was the delayed increase in free radicals after a single seizure in the later phases of recovery., J. Mareš ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Pulmonary hypertension resulting from chronic hypoxia is at least partly caused by the increased production of reactive oxygen species (ROS). The goal of the presented study was to investigate the dynamics and the site of production of ROS during chronic hypoxia. In our study Wistar rats were kept for 1, 4 and 21 days in an isobaric hypoxic chamber (FiO2=0.1), while controls stayed in normoxia. We compared NO production in expired air, plasma and perfusate drained from isolated rat lungs and measured superoxide concentration in the perfusate. We also detected the presence of superoxide products (hydrogen peroxide and peroxynitrite) and the level of ROS-induced damage expressed as the concentration of lipid peroxydation end products. We found that the production and release of ROS and NO during early phase of chronic hypoxia has specific timing and differs in various compartments, suggesting the crucial role of ROS interaction for development of hypoxic pulmonary hypertension., D. Hodyc ... [et al.]., and Obsahuje seznam literatury
The aim of the present study was to investigate the mechanism of vasorelaxant responses induced by red wine polyphenolic compounds (Provinol). Rings of rat femoral artery with or without functional endothelium were set up in a myograph for isometric recording and precontracted with phenylephrine (10-5 M). Provinol in cumulative doses (10-9 to 10-3 mg/ml) elicited endothelium- and dose-dependent relaxation of the artery with maximal relaxation of 56 % at the concentration of 10-5 mg/ml. The relaxant responses to Provinol correlated well with the increase of NO synthase activity in the vascular tissue after administration of cumulative doses of Provinol (10-9 to 10-3 mg/ml). NG-nitro-L-arginine methylester (L-NAME, 3x10-4 M) significantly attenuated the endothelium-dependent relaxation produced by Provinol. Administration of L-arginine (3x10-5 M) restored the relaxation inhibited by L-NAME. The relaxant responses of Provinol were abolished in the presence of Ca2+-entry blocker, verapamil (10-6 M). Administration of hydrogen peroxide (H2O2) abolished acetylcholine (10-5 M)-induced relaxation of the rat femoral artery, while administration of Provinol (10-5 mg/ml) together with H2O2 helped to maintain the acetylcholine-induced relaxation. Provinol only partially affected the concentration-response curve for the NO donor sodium nitroprusside-induced relaxation in rings without endothelium. In conclusion, Provinol elicited endothelium-dependent relaxation of rat femoral artery by the Ca2+-induced increase of NO synthase activity and by protecting NO from degradation., W. Zenebe, O. Pecháňová, R. Andriantsitohaina., and Obsahuje bibliografii
Two mechanisms contribute in the development of pulmonary hypertension in pulmonary embolism (PE) - obstruction of pulmonary blood vessels and vasoconstriction. We hypothesize that hypoxia, increased shear stress and/or activation of gathered leukocytes in the PE may cause a release of reactive oxygen species (ROS). Therefore our aim was to determine the influence of the ROS scavenger Tempol on pulmonary hypertension and to d escribe NO synthase activity and production of NO oxidative products (NOx) after PE. In general anesthesia sephadex microspheres suspended in PSS were applied in right jugular vein as the pulmonary microembolism. Than we measured in isolated salt solution -perfused lungs the changes in perfusion pressure, activity of NO synthase and NOx plasma concentration in 7 groups of rats: C: control group (n=5), CN: C + sodium nitroprusside (SN) (n=5), EN: PE + SN (n=5), ETN: Tempol + PE + SN (n=5), CL : C + L -NAME (n=5 ), EL: PE + L-NAME (n=5), ETL: Tempol + PE + L -NAME (n=5). Tempol was applied intraperitoneally before PE. Animals that received Tempol (groups TN, TL) had significantly lower basal perfusion pressure than those which did not rec eive Tempol (EN, EL). Overa ll we measured a higher decrease of perfusion pressure than in the control group (C) after applica tion of SN. Administration of L-NAME after PE (EL) increased the pressure more than in the control group (NL). NOx concentration was higher after PE. We found that preventive administration of Tempol decreases the increase in perfusion pressure after PE. PE increased NO release and concentration of NOx., R. Mizera, D. Hodyc, J. Herget., and Obsahuje bibliografii
Factors modulating cardiac susceptibility to ischemia-reperfusion (I/R) are permannetly attracting the attention of experimental cardiology research. We investigated, whether continuous 24 h/day light exposure of rats can modify cardiac response to I/R, NO-synthase (NOS) activity and the level of oxidative load represented by conjugated dienes (CD) concentration. Two groups of male adult Wistar rats were studied: controls exposed to normal light/dark cycle (12 h/day light, 12 h/day dark) and rats exposed to continuous light for 4 weeks. Perfused isolated hearts (Langendorff technique) were exposed to 25 min global ischemia and subsequent 30 min reperfusion. The recovery of functional parameters (coronary flow, left ventricular developed pressure, contractility and relaxation index) during reperfusion as well as the incidence, severity and duration of arrhythmias during first 10 min of reperfusion were determined. The hearts from rats exposed to continuous light showed more rapid recovery of functional parameters but higher incidence, duration and severity of reperfusion arrhythmias compared to controls. In the left ventricle, the NOS activity was attenuated, but the CD concentration was not significantly changed. We conclude that the exposure of rats to continuous light modified cardiac response to I/R. This effect could be at least partially mediated by attenuated NO production., R. Važan, P. Janega, S. Hojná, J. Zicha, F. Šimko, O. Pecháňová, J. Styk, L'. Paulis., and Obsahuje bibliografii
V práci je prezentovaná problematika tvorby vol'ných radikálov kyslíka, ich elektrónovej štruktúry, vlastností a metódy detekcie. Pozornosť je venovaná poškodzujúcemu účinku vol'ných radikálov na nukleové kyseliny, proteíny a biologické membrány., The article is dealing with the topic of oxygen-containing free radicals, their electronic structure, properties and methods of detection. Attention is paid to chemical and biochemical aspects of these free radicals, i.e., the sources of their generation, the metal-mediated formation of the reactive species and the damage to lipids, proteins and nucleic acids initiated by them., Klaudia Jomová, Ľubomír Zelenický, Vlasta Brezová, Marián Valko., and Obsahuje bibliografii
The quality of stored blood can be deteriorated by hemolysis caused by free radicals. The purpose of this study was to elucidate whether neutrophile leukocytes are the source of free radicals in stored blood as in hemodialyzed patients. Resuspensions with low (LL) or high (HL) leukocyte concentrations were prepared from samples of twenty healthy volunteers. The samples were incubated for 10 days at 4 °C and then for one day at 37 °C. Markers of hemolysis and free radical metabolism were examined before and after incubation in LL and HL samples. In spite of the difference of leukocytes counts in LL and HL resuspensions (p<0.0001), the pre-incubation values of all laboratory parameters were practically identical. In post-storage samples, superoxide dismutase and glutathione peroxidase activities did not differ in either group. Reduced glutathione in erythrocytes and extracellular antioxidant capacity were insignificantly lower in HL resuspensions, but the increase of malondialdehyde was much more pronounced in the HL samples (p<0.0001). The degree of hemolysis, expressed as the extracellular increase of potassium (p<0.001), hemoglobin (p<0.05) and lactate dehydrogenase (p<0.05), was higher in the HL samples. Our results support the hypothesis that leukocytes participate in free radical production in stored blood., J. Racek, R. Herynková, V. Holeček, J. Faltysová, I. Krejčová., and Obsahuje bibliografii