Inhalational anesthetic-induced preconditioning (APC) has been shown to reduce infarct size and attenuate contractile dysfunction caused by myocardial ischemia. Only a few studies have reported the effects of APC on arrhythmias during myocardial ischemia-reperfusion injury, focusing exclusively on reperfusion. Accordingly, the ai m of the present study was to examine the influence of APC on ventricular arrhythmias evoked by regional no-flow ischemia. APC was induced in adult male Wistar rats by 12-min exposures to two different concentrations (0.5 and 1.0 MAC) of isoflurane followed by 30-min wash-out periods. Ventricular arrhythmias were assessed in the isolated perfused hearts during a 45- min regional ischemia and a subsequent 15-min reperfusion. Myocardial infarct size was determined after an additional 45 min of reperfusion. The incidence, severity and duration of ventricular arrhythmias during ischemia were markedly reduced by APC. The higher concentration of isoflurane had a larger effect on the incidence of ventricular fibrillation than the lower concentration. The incidence of ventricular tachycardia and reversible ventricular fibrillation during reperfusion was also significantly reduced by APC; the same was true for myocardial infarct size. In conclusion, we have shown that preconditioning with isoflurane confers profound protection against myocardial is chemia- and reperfusion-induced arrhythmias and lethal myocardial injury., H. Říha ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
We examined the protective effect of radon inhalation on streptozotocin (STZ)-induced type-1 diabetes in mice. Mice inhaled radon at concentrations of 1000, 2500, and 5500 Bq/m3 for 24 hours before STZ administration. STZ administration induced characteristics of type-1 diabetes such as hyperglycemia and hypoinsulinemia; however, radon inhalation at doses of 1000 and 5500 Bq/m3 significantly suppressed the elevation of blood glucose in diabetic mice. Serum insulin was significantly higher in mice pre-treated with radon at a dose of 1000 Bq/m3 than in mice treated with a sham. In addition, superoxide dismutase activities and total glutathione contents were significantly higher and lipid peroxide was significantly lower in mice pre-treated with radon at doses of 1000 and 5500 Bq/m3 than in mice treated with a sham. These results were consistent with the result that radon inhalation at 1000 and 5500 Bq/m3 suppressed hyperglycemia. These findings suggested that radon inhalation suppressed STZ-induced type-1 diabetes through the enhancement of antioxidative functions in the pancreas., Y. Nishiyama, ... [et al.]., and Obsahuje seznam literatury
One hundred years ago Heike Kamerlingh Onnes arrived to one of the most important breakthroughs of 20th century physics - he discovered superconductivity. His finding as in many other cases in the history of science had been a result of use of a very new experimental technique. He used the cryogenic equipment in his Leiden's laboratory with the liquid helium cryocooler and measured electrical properties of metals near the absolute zero temperature. When cooled down to extremely low temperatures, near 4 Kelvin, very pure mercury suddenly lost its electrical resistance completely. Many major physicists of 20th century, experimentalists as well as theorists, devoted their life efforts to exploration of the mysterious properties of superconductors. Superconductivity has been shown to be one of the rare cases where quantum physics is observed on a macroscopic scale. Many chemical elements and thousands of compounds have been found to be superconducting. Fifty years after the discovery important practical applications such as strong magnets for laboratories and magnetic-resonance-imaging in hospitals came to the market. But more than seventy five years the superconducting materials had been functioning only at extreme cold, below 23 K (-250°C). In 1986 the "hightemperature superconductor's" era started with materials superconducting at -100°C. This paper surveys the history and the latest research into one of today's most fascinating physics and promising technologies., Peter Samuely., and Obsahuje bibliografii
The effect of suramin, an inhibitor of G protein regulated signalling, was studied on the membrane currents induced by noxious heat and by capsaicin in cultured dorsal root ganglia neurones isolated from neonatal rats. Whole-cell responses induced by a heat ramp (24-52 °C) were little affected by suramin. The noxious heat-activated currents were synergistically facilitated in the presence of 0.3 µM capsaicin 13.2-fold and 6.3-fold at 40 °C and 50 °C, respectively. In 65% of neurones, the capsaicin-induced facilitation was inhibited by 10 µM suramin to 35±6 % and 53±6 % of control at 40 °C and 50 °C (S.E.M., n=15). Suramin 30 µM caused a significant increase in the membrane current produced by a nearly maximal dose (1 µM) of capsaicin over the whole recorded temperature range (2.4-fold at 25 °C and 1.2-fold at 48 °C). The results demonstrate that suramin differentially affects the interaction between capsaicin and noxious heat in DRG neurones and thus suggest that distinct transduction pathways may participate in vanilloid receptor activation mechanisms., V. Vlachová, A. Lyfenko, L. Vyklický, † R.K. Orkand., and Obsahuje bibliografii
In the Baixo Vouga region of north-central Portugal, forests occupy half of the territory, of which two thirds are Eucalypts plantations. The hydrological implications of this large-scale introduction of eucalypt are unknown and the aim of this exploratory study, realized in the Caramulo Mountains, was to describe overland flow (OLF), subsurface flow (SSF) and stream flow (Q) in a catchment dominated by Eucalyptus plantations. The main conclusions are that annual OLF rate is low, spatially heterogeneous between 0.1% and 6% and concentrated during the wet season as saturation excess, particularly as return flow. Infiltration-excess OLF due to the strong soil water repellence (SWR) is dominant during dry season, but produces residual runoff amount. SSF is the principal mechanism of runoff formation. It originates from matrix flow and pipe flow at the soil-bedrock interface, principally during the wet season. Matrix flow is correlated with soil moisture (SM) content, with a threshold of 25 %. Pipe flow starts with saturation of soil bottom but without saturation of the entire soil profile, due to a large network of macropores. Stream flow response is highly correlated with matrix flow behaviour in timing and intensity. SWR induces a very patchy moistening of the soil, concentrates the fluxes and accelerates them almost 100 times greater than normal percolation of the water in the matrix.
Wheat seedlings (Triticum aestivum L.) develop plastids (etioplasts and chloroplasts) which exhibit alterations in inner membrane organisation after treatment with Norflurazon (NF), an inhibitor of carotenoid biosynthesis. In dark-grown plants, it results in a decreased amount of partitions (contact zones) between prothylakoids. Under weak red radiation (WRR), plants contain chloroplasts devoid of grana. Using the fluorescent probe 9-amino acridine (9-AA), the average surface charge density of isolated prothylakoids (PTs) was -21.8±3.2 mC m-2 and -27.4±2.6 mC m-2 in the control and after treatment, respectively. Thylakoid membranes isolated from plants grown under WRR exhibited slightly more negative values, -23.5±2.9 mC m-2 and -29.0±2.1 mC m-2, in control and after NF treatment, respectively. The surface charge density of de-stacked thylakoids from greenhouse-grown untreated plants, containing extensive grana stacking, was -34.3±2.5 mC m-2. Assays using the fluorescent probe of DPH (1,6-diphenyl-1,3,5-hexatriene) showed a higher polarisation value when incorporated into thylakoids from NF-treated plants compared to untreated plants grown under WRR. The highest polarisation value was found in untreated plants grown in the greenhouse. This indicates a lower rotation transition of the probe in the lipid environment of thylakoids after NF treatment, which can be interpreted as more rigid membranes. Hence the surface charge density and the mobility of membrane components may play a major role for the formation of partitions in dark-grown plants and in the formation of grana in plants grown under WRR.