Gadolinium as an Inhibitor of Ionic Currents in Isolated Rat Ventricular Cardiomyocytes.

The whole-cell patch-clamp technique was used to examine the effect of gadolinium Gd3+ (a non-specific blocker of mechanically gated current IMGCh, a component of late current IL) on ionic currents in insolated rat ventricular cardiomyocytes alone and in combination with the blockers of L-type calcium currents (ICaL) nifedipine (10 µM) or verapamil (1 µM). In K+in/K+out or Cs+in/Cs+out media, blockade of ICaL produced no effect on IL at negative potentials, but inhibited IL at positive ones. In K+in/K+out medium, Gd3+ (5 µM) decreased the net persistent current (Inp) at -45 mV from 198.6±6.4 to 96.7±9.5 pA over 15 min. Gd3+ alone or in combination with ICaL blockers shifted the reversal potential of IL to more negative values. At negative potentials, Gd3+ decreased IK1 and inward current including IMGCh. At positive potentials, Gd3+ alone or in combination with ICaL blockers decreased IL. When applied for 15 min in Cs+in/Cs+out medium at -45 mV, Gd3+ produced no effect on net current and inward and outward components of IL. Thus, Gd3+ can be viewed as a specific blocker of IMGCh only in Cs+ medium.

[The role of calcium in reaction of the heart for mechanical stress].

The article deals with the role of Ca2+ in four possible mechanisms of cardiac muscle response to mechanical stretch. First, the Ca2+ role is analysed in the changed contractive myocardium function under mechanical stretch. Second, discussed are the direct proofs of redistributing intercellular ions occurring at axial stretch of single cardiomyocytes. Given are the experimental proofs relating the role of Ca2+ and mechanical stretch. Third, considered is the change of electric activity in response to mechanical stretch. Fourthly, considered are the role of Ca2+ in expression and secretion of proteins activated by mechanical stretch.

[Antibodies to DNA in the blood of patients with tick-borne encephalitis]. / Antitela k DNK v krovi bol'nykh kleshchevym éntsefalitom.

A comparison of relative levels of autoantibodies (Abs) to both native (n) and denatured (d) DNA in the blood of 55 patients with tick-borne encephalitis (TBE) was carried out. 31% of patients with TBE was shown to have an increased level Abs to nDNA and 40% of patients demonstrate increased level of Abs to dDNA. The percent of TBE patients with increased concentration of anti-nDNA Abs higher then that in patients with multiple sclerosis (18%) and some other autoimmune diseases (6-18%), but comparable with that for patients with systemic lupus erythematosus (38%) and polymyositis (42%). In contrast to patients with systemic lupus erythematosus and multiple sclerosis, the level of Abs to nDNA in patients with TBE is higher than the level of Abs to dDNA. Correlation coefficients of Ab levels to both n- and dDNA were estimated for group of patients in whole and for separate subgroups with different type of disease (temperature reaction, feverishness and meningitis). Analysis of correlation between titres of anti-DNA Abs and three standard biochemical markers of TBE (activity of aspartate- and alanine-aminotransferases, and concentration of whole bilirubin) for 22 patients with TBE was carried out. Statistically significant correlation was revealed only between the level of Abs to nDNA and activities of aspartate- and alanine-aminotransferases, correlation coefficients are equal to +0.44 and +0.48, respectively.