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