Experimentally based models of cardiac cells have been developed since 1960.The early models were based on extension of the Hodgkin-Huxley nerve impulse equations. Including only a few membrane currents they were able to successfully reconstruct the depolarization and repolarization of cellular membrane. Since that time, the models have underwent extensive modifications and reached a high degree of physiological detail. This short review is aimed to outline the history of their development and show the importance of computer modelling for the research in cardiac cell electrophysiology. and Obsahuje seznam literatury
Hypotonic solution alters ion channel activity, but little attention has been paid to voltage-dependent sodium channels. The aim of this study was to investigate the effects of hypotonic solution on transient sodium currents (INaT) and persistent sodium currents (INaP). We also explored whether the intracellular signal transduction systems participated in the hypotonic modifications of sodium currents. INaT and INaP were recorded by means of whole-cell patch-clamp technique in isolated rat ventricular myocytes. Our results revealed that hypotonic solution reduced INaT and simultaneously augmented INaP with the occurrence of interconversion between INaT and INaP. Hypotonic solution shifted steady-state inactivation to a more negative potential, prolonged the time of recovery from inactivation, and enhanced intermediate inactivation (IIM). Ruthenium red (RR, inhibitor of TRPV4), bisindolylmaleimide VI (BIM, inhibitor of PKC), Kn-93 (inhibitor of Ca/CaMKII) and BAPTA (Ca2+-chelator) inhibited the effects of hypotonic solution on INaT and INaP. Therefore we conclude that hypotonic solution inhibits INaT, enhances INaP and IIM with the effects being reversible. TRPV4 and intracellular Ca2+, PKC and Ca/CaMKII participate in the hypotonic modifications of sodium currents., L. Hu ... [et al.]., and Obsahuje seznam literatury
Je popsána problematika a návrh systému pro prevenci možného vzniku síňo-jícnové fistuly při izolaci plicních žil, která je součástí elektrofyziologické srdeční operace, jejímž cílem je léčba fibrilace srdečních síní. Návrh systému pro měření jícnové teploty je aktivitou Clever Technologies, s.r.o. (spin-off firma Univerzity Karlovy v Praze a ČVUT v Praze), Společného biomedicínského pracoviště ČVUT v Praze a UK v Praze, Fakulty biomedicínského inženýrství ČVUT, 1. lékařské fakulty UK a předních klinických pracovišť. V první části je stručně podán přehled o používaných technikách při operačním zákroku při léčbě fibrilací síní, o jeho průběhu a možných komplikacích. Navazuje popis návrhu systému pro měření teploty v jícnu a charakteristika jeho řešení. and Jiří Brada, Jan Kašpar, Štěpán Královec, Pavel Smrčka, Karel Hána, Radek Fiala.