[The influence of small doses of exogenic nitrite on oxidative modifications of water-soluble proteins of rat cardiac and skeletal muscle].

The influence of small doses of exogenic nitrite on reversible and irreversible oxidative modifications of water-soluble proteins of rat cardiac and skeletal muscle was studied with the aid of redox 2D-electrophoresis and colorimetric determination of protein carbonyl group, correspondingly. To explain the absence of significant changes under hypoxia induced by nitrite the known hypothesis about nitrite inhibition of some sites of mitochondrial electron transporting chain decreasing free radical quantity was discussed.

[Intracellular disorders in the dog myocardium in low cardiac output syndrome caused by massive hemorrhage, approaches to correction]. / Vnutrikletochnye narusheniia v miokarde u sobak pri sindrome malogo serdechnego vybrosa, vyzvannom massivnoi krovopoterei, puti korrektsii.

It was shown on dog experiments that disorders in the phosphorylation-proteolysis-calcium transport system in the sarcoplasmatic reticulum of pathologically changed myocardium are an important component of cardiac activity depression in massive blood loss. Low cardiac output can be corrected by ammonium molibdate, phosphoprotein phosphatase inhibitor, and contrycal, proteolysis inhibitor.

[Thyroid hormones and melatonin as means of antioxidant therapy]. / Tireoidnye gormony i melatonin kak sredstva antioksidantnoi terapii.

The possibility of involvement of thyroid hormones and melatonin in cell protection from damage by active oxygen forms (hydroxyperoxide, superoxide radical, and hypochlorite) was investigated. The intensity of inhibition of luminol-dependent chemiluminescence induced by neutrophils and active oxygen forms in the presence of hormones was evaluated. Antioxidant activities of the enzymes were compared with that of glutathione. Probable mechanisms of antioxidant effect of the studied hormones are discussed.

[The effect of OCl- and Ag+ on active and passive calcium transport in the sarcoplasmic reticulum]. / Deistvie OCl- i Ag+ na aktivnyi i passivnyi transport kal'tsiia v sarkoplazmaticheskom retikulume.

After hypochlorite (OCl-) treatment of the aortic smooth muscle sarcoplasmic reticulum (SR), the membrane microviscosity increases considerably in "bound" lipid regions in comparison with protein-free regions. OCl- induces the inhibition of active and the enhancement of passive calcium transport in SR. Treatment of SR vesicles with Ag+ and then with OCl- (but not in the reverse order) leads to the enhancement of the activating effect of OCl- on passive calcium release from the vesicles. It is concluded that the enhancement effect is due to the OCl(-)-induced increase in the passive permeability of the SR membrane for Ca2+ as a result of pore formation in the lipid bilayer.

[Study of dynein ATPase by oxygen isotope exchange H2(18)O in equilibrium with [16O]-Pi]. / Issledovanie dineinovoi ATPazy metodom izotopnogo obmena kisloroda H2 18O ekvilibr [16O]--Pi.

The oxygen isotope exchange reactions catalyzed by sea urchin Strongylocentrotus intermedius spermatozoa dynein I were studied with a view of comparing molecular mechanisms of ATP hydrolysis by dynein and myosin ATPases. It was demonstrated that the isotope exchange takes place during ATP hydrolysis and during enzyme incubation with ADP and Pi and is absent when the enzyme is incubated with Pi. It was assumed that the molecular mechanisms of ATP hydrolysis by dynein I and myosin are identical.

[18O-exchange reactions in skeletal, cardiac and smooth muscle myosin]. / 18O-obmennye reaktsii v sisteme miozina skeletnykh, cerdechnoi i gladkikh myshts.

18O-exchange reactions of skeletal, cardiac and smooth muscle myosin were studied. All investigated preparations of myosin catalyse two types of 18O-exchange--intermediate and direct exchanges in the presence of Mg2+. The dependence of 18O-exchange extent on divalent cations have appeared to be similar for different muscle types. This supports the hypothesis of similarity of ATP hydrolysis molecular mechanisms by myosin of different origin.

[18 O-exchange reactions catalyzed by myosin of calf intestine smooth muscle]. / O 18-obmennye reaktsii, kataliziruemye miozinom gladkikh myshts kishechnika telenka.

18O-exchange reactions of smooth muscle myosin of calf intestine were studied. Smooth muscle myosin, similar to skeletal myosin, catalyses two types of 18O-exchange reactions--intermediate and direct. Only quantitative differences of the exchange intensity are observed. 18O-exchange dependence on bivalent cation and nucleotide nature is found. The comparison of 18O-exchange characteristics for myosins of smooth and skeletal muscles confirms the hypothesis on the similarity of molecular mechanisms of ATP hydrolysis by myosin from different muscle types.

[Oxygen isotope exchange reactions in synaptosomal plasmatic membrane system]. / Reaktsii izotopnogo obmena kisloroda neorganicheskogo fosfata v sisteme plazmaticheskikh membran sinaptosom.

Mg2+-Dependent, Ca2+-activated adenosine triphosphatase (E. C. 3.6.1.4) of synaptosomal plasmatic membrane from cow brain catalyses isotopic exchange of oxygen atoms: KH2P18O 4 in equilibrium H2O, the degree of exchange depending on Ca2+ concentration. The 18O-exchange catalysis suggests that the enzyme under consideration acts as a transport ATPase.