[Formation of a new type of dinitrosyl iron complexes bound to cysteine modified with methylglyoxal].

It has been shown that interaction of cysteine dinitrosyl iron complexes with methylglyoxal leads to the formation of a new type of dinitrosyl iron complexes., EPR spectrum of these complexes essentially differs from spectra of dinitrosyl iron complexes containing unmodified thiol. The products of the cysteine reaction with methylglyoxal are hemithioacetals, Schiff bases and thiazolidines, which most likely serve as ligands for the new type of dinitrosyl iron complexes.

Biopharmacology of enzyme conjugates: vasoprotective activity of supramolecular superoxide dismutase-chondroitin sulfate-catalase derivative.

Bienzyme conjugate was obtained by the covalent connection of superoxide dismutase with catalase through endothelial glycocalyx glycosaminoglycan - chondroitin sulfate (SOD-CHS-CAT). This SOD-CHS-CAT conjugate has vasoprotective activity in respect to platelet interactions, tonus of the ring arterial fragment of a rat blood vessel, as well as normalization of hemodynamic parameters in rats and rabbits in conditions of oxidative stress caused by the administration of hydrogen peroxide. The SOD-CHS-CAT conjugate had antiplatelet potential due to its antiaggregation action manifested through the combination of enzyme activities and an acquired supramolecular structure.

On the nature of a compound formed from dinitrosyl-iron complexes with cysteine and responsible for a long-lasting vasorelaxation.

The nature of a compound able to induce long-lasting (> or =20 min) relaxation of rat abdominal aorta rings after addition of rapidly (within several minutes) disappeared mono- and binuclear dinitrosyl iron complexes with cysteine (M- and B-DNICs, respectively) (10 micromol) to the Krebs medium has been investigated. It has been found that long-lasting vasorelaxation is not induced either by S-nitrosocysteine formed upon decomposition of DNICs or by accumulation of free nitric oxide molecules or nitrite remaining in the incubation medium. Long-term air bubbling of the Krebs medium initially containing M-DNIC is accompanied by conversion of the complex first into B-DNIC, which represents a Roussin's red salt cysteine ester and then into a more stable diamagnetic compound X, which displays an intense absorption band at 278 nm.

Vasorelaxing activity of stable powder preparations of dinitrosyl iron complexes with cysteine or glutathione ligands.

Vasorelaxant activity of new stable powder preparations of dinitrosyl iron complexes (DNIC) with thiol-containing ligands was investigated on rat abdominal aorta rings. The preparations preserve their physicochemical characteristics (EPR and optical absorption) if stored for a long time in dry air (at least half-year). Three preparations of DNIC were tested: diamagnetic dimeric DNIC with glutathione (DNIC-GS 1:2) or cysteine (DNIC-cys 1:2) and paramagnetic monomeric DNIC with cysteine (DNIC-cys 1:20).

[Prevention of reperfusion-induced arrhythmia by Na+/H+ exchange block].

Using the isolated papillary muscle and rat hearts, perfused by Langendorf, the effects of the Na+/H+ exchange blocker, ethylisopropylamiloride (EIPA), on electrical activity and contractility, and induction of ischemic and reperfusion arrhythmias were studied. In the experiments with regional ischemia and reperfusion of an isolated heart (the ligation of the left anterior descending coronary artery for 10 minutes), EIPA (5 microM) effectively abolished reperfusion fibrillations, reducing the incidence of the long fibrillations from 60% (in the controls) to 8%, and increased nearly five-fold the time interval prior to their onset. Antiarrhythmic action of EIPA seems to be unconnected with the direct block of ionic channels, because 5 microM of this compound did not significantly change the action potential parameters, first derivative Vmax and the contractile response of the papillary muscle in normal conditions.

[Anti-arrhythmic and vasodilator actions of the antioxidant fenozan in acute ischemia and reperfusion].

At the experiments with the isolated rat hearts, prepared by Langendorff, the anti-arrhythmic dose-effects of the water-soluble antioxidant fenozan from the class of steric-hindrance phenols were studied at condition of regional ischemia and reperfusion, as well as its action on the coronary flow. 3.6.

[Protective action of an antioxidant of the 3-hydroxypyridine class on the contractility and electrogenesis of the heart muscle in hypoxia and reoxygenation].

The effect of SD-6, a 3-hydroxypyridine antioxidant, on the pattern of variation in contraction intensity, contracture and membrane potentials were assessed in experimental studies on isolated left ventricular papillary muscles of rats, exposed to hypoxia and reoxygenation. The antioxidant considerably limited hypoxic and reperfusion contracture, its efficiency increasing with a concentration reduced to 10(-7) g/ml. Contraction intensity and duration of action potentials, diminished by hypoxia, were only recovered by reoxygenation, if the antioxidant was present.

[Anti-arrhythmia action of the antioxidant SD-6 in the development of ischemic and reperfusion rhythm disorders of the isolated rat heart].

An antiarrhythmic action of water-soluble antioxidant SD-6 from 3-hydroxypyridine class and its effect on the transmembrane potentials were studied using the isolated rat heart and papillary muscle. Ischemia was induced by the occlusion of the left anterior descending coronary artery. 10 minutes later the ligation was removed and reperfusion was achieved.

[Comparative analysis of the changes in myocardial electrical and contractile activity in rats exposed to rubomycin and its nitroxyl derivative].

A comparative analysis was performed of changes in the contractile and electrical activity of the rat myocardium in experiments on isolated papillary muscles, obtained 2-2.5 months after the discontinuation of chronic administration of rubomicin in 0.7 mg/kg and ruboxil in 3 mg/kg dose to the animals.