We aimed to determine the impact of Ca2+-related disorders induced in intact animal hearts on ultrastructure of the cardiomyocytes prior to occurrence of severe arrhythmias. Three types of acute experiments were performed that are known to be accompanied by disturbances in Ca2+ handling. Langedorffperfused rat or guinea pig hearts subjected to K+-deficient perfusion to induce ventricular fibrillation (VF), burst atrial pacing to induce atrial fibrillation (AF) and open chest pig heart exposed to intramyocardial noradrenaline infusion to induce ventricular tachycardia (VT). Tissue samples for electron microscopic examination were taken during basal condition, prior and during occurrence of malignant arrhythmias. Cardiomyocyte alterations preceding occurrence of arrhythmias consisted of non-uniform sarcomere shortening, disruption of myofilaments and injury of mitochondria that most likely reflected cytosolic Ca2+ disturbances and Ca2+ overload. These disorders were linked with non-uniform pattern of neighboring cardiomyocytes and dissociation of adhesive junctions suggesting defects in cardiac cell-to-cell coupling. Our findings identified heterogeneously distributed high [Ca2+]i-induced subcellular injury of the cardiomyocytes and their junctions as a common feature prior occurrence of VT, VF or AF. In conclusion, there is a link between Ca2+-related disorders in contractility and coupling of the cardiomyocytes pointing out a novel paradigm implicated in development of severe arrhythmias., N. Tribulova, V. Knezl, B. Szeiffova Bacova, T. Egan Benova, C. Viczenczova, E. Gonçalvesova, J. Slezak., and Obsahuje bibliografii
There is an overlap of carrier-mediated L-amino acid transport and apparent simple diffusion when measured in intestinal brush border membrane vesicles. Using L-threonine and L-glutamine as representative amino acids, this study was undertaken to estimate apparent simple diffusion of L-amino acids and to establish the effective dosage of HgCl2 for completely blocking carrier-mediated L-amino acid transport in porcine jejunal enterocyte brush border membrane vesicles. Jejunal mucosa was scraped from three pigs weighing 26 kg. Enterocyte brush border membrane vesicles, with an average enrichment of 24-fold in sucrase specific activity, were prepared by Mg2+-precipitation and differential centrifugation. In vitro uptake was measured by the fast filtration manual procedure. HgCl2 blocked the carrier-mediated initial transport of L-threonine and L-glutamine under Na+-gradient condition in a dose-dependent manner. At the minimal concentration of 0.165 mmol HgCl2 mg-1 protein, carrier-mediated L-threonine and L-glutamine transport was completely inhibited. The apparent L-threonine and L-glutamine diffusion was estimated to be 8.6±0.7 and 12.4±1.0 % of the total uptake at the substrate concentrations of 5 mM (L-threonine) and 50 mM (L-glutamine). Therefore, the treatment of porcine brush border membrane vesicles with a minimum of 0.165 mmol HgCl2 mg-1 protein completely blocks carrier-mediated L-amino acid transport and enables the direct estimation of apparent L-amino acid diffusion in enterocyte brush border membrane vesicles., M. Z. Fan, O. Adeola, E. K. Asem., and Obsahuje bibliografii
Aquaporins (AQPs) are water channel proteins responsible for water homeostasis and important for proper functioning of all body systems, including reproductive structures. This study was designed to determine their localization and quantitative changes in the pig ovary during different stages of the estrous cycle and early pregnancy. The expression of AQP 1, 5 and 9 proteins was determined by immunocytochemistry and Western blot analyses. AQP1 was found in the plasma membranes of capillary endothelium, AQP5 - in the plasma membranes of granulosa cells of developing follicles and flattened follicle cells of the primordial follicles, and AQP9 - in granulosa cells of the developing follicles. In the cyclic pigs, the expression of AQP1 and 5 proteins was the highest on Days 18-20, but did not change significantly between Days 2-4, 10-12 and 14-16 of the cycle. In pregnant pigs (Days 14-16 and 30-32), the expression of AQP1 and 5 did not change and was similar to that observed during Days 10-12 and 14-16. In turn, AQP9 expression did not change between all studied periods. In conclusion, studied AQP are localized in different cells populations, the endothelial and granulosa cells, and AQP1 and 5 seem to be crucial for follicular development in pigs., A. Skowronska, P. Mlotkowska, M. Eliszewski, S. Nielsen, M. T. Skowronski., and Obsahuje bibliografii
This study explores the biological validation of markers of acute stress in pigs subjected to transportation for slaughter. The stress markers selected for monitoring were neopterin and cortisol. Their levels in pig serum were measured for two porcine stress syndrome genotypes, NN and Nn, after a 30-min transport to a slaughterhouse. Blood samples were withdrawn before transport (control group) and immediately after the animals' arrival (experimental group). The values of neopterin and cortisol measured before the transport were 5.60±1.65 nm ol/l and 273.54±66.17 nmol/l respectively. After the transfer, the concentration of cortisol rose significantly compared to the control (355.69±85.13 nmol/l, p<0.01). Neopterin concentrations in the serum (8.25±1.60 nmol/l) were also significantly higher (p<0.01) after transportation. The elevated concentrations of both analytes were found to be independent of the genotype. These results document the stimulation of the endocrine system and the immune system that develops in animals undergoing transportation for slaughter., K. Breineková, M. Svoboda, M. Smutná, L. Vorlová., and Obsahuje bibliografii a bibliografické odkazy
The aim of the present study was to investigate the distribution and density of noradrenergic nerve fibres (NNFs), content of catecholamines (CATs) and steroids in the cystic ovaries of gilts receiving DXM from middle luteal phase. Cystic status of ovaries was induced by i.m. DXM injections on days 7-21 of the estrous cycle. During the same time, gilts in the control group received saline. The ovaries were collected on predicted day 11 of the second studied estrous cycle. The cystic ovaries were supplied by more numerous NNFs than the control gonads. Moreover after DXM injections, the content of CATs and progesterone and androstendione (A4) in the cystic wall were elevated, while the levels of A4, testosterone and estradiol-17β in the cystic fluid were lowered. Our results show that in the porcine cystic ovaries, induced by DXM injections from middle phase of estrous cycle, increased the density of NNFs and level of CATs, and that it was accompanied by changes in the content of steroids. Moreover, this study is a further confirmation that the morphological and functional changes of cystic ovaries are partly dependent on phase of the estrous cycle in which the induction of the ovarian cysts was initiated., A. Kozłowska, ... [et al.]., and Obsahuje seznam literatury