[Supercarcinogens and supermutagens--nitrosoalkoxyalkylamines--effective producers of nitrogen oxide]. / Superkantserogeny i supermutageny--nitrozoalkoksialkilaminy--éffektivnye produtsenty okisi azota.

Nitrosoalcoxyalkylamines are more efficient producers of nitrogen oxide in vivo than nitrosoalkylamines. Production of nitrogen oxide was monitored by EPR. The patterns of denitrosylation have been studied. The ability of the studied compounds to produce nitrogen oxide in vivo may be related to their carcinogenic and mutagenic action.

[Lipoproteins as a factor regulating vascular tonus]. / Lipoproteidy kak faktor reguliatsii tonusa sosudov.

Lipoproteins (very low, low and high density) purified from canine fresh plasma produced relaxation of isolated dog coronary artery and rabbit aortic ring segments precontracted with potassium, 30 mM or phenylephrine, 10(-6) M, respectively. No apparent species-specific effects of lipoproteins were revealed and they produced relaxation of other species vessels as well, which differed quantitatively. No apparent endothelium-dependent relaxation produced by animals' lipoproteins was evident. The interference of lipoproteins with some steps in electromechanical coupling is suggested which seemingly result to decrease in excitability of voltage and receptor operated calcium channels of smooth muscle cell membrane. The role of lipoproteins seems to be in maintenance of low level of smooth muscle cell membrane excitability.

[Endothelial relaxation factor as a local modulator of arterial function. The possibility of stabilization]. / Endotelial'nyi faktor rasslableniia kak lokal'nyi moduliator funktsii arterii. Vozmozhnost' stabilizatsii.

Endothelium-derived relaxing factor (EDRF) exerted no inhibitory effect on papillary muscles or the rat portal vein. Externally applied acetylcholine did not reach aorta endothelium to stimulate the EDRF release in rabbits, nor bradykinin in the pig coronary artery segments. Acetylcholine penetrated, however, canine femoral artery wall and stimulated the release of EDRF. Stabilizing of the EDRF released from perfused rabbit thoracic aorta, seems to be possible.

[Endothelial function and spasm of the coronary artery]. / Funktsiia éndoteliia i spazm koronarnoi arterii.

The tone of isolated segments of human coronary arteries with manifestations of atherosclerotic lesions was increased by serotonin (10(-6) M) or prostaglandin F2 alpha (10(-6) M). Insignificant endothelium-dependent relaxation induced by bradikinin, calcium ionofore A-23187 or substance P was observed in several segments with marked (plaque) as well as macroscopically invisible sclerotic lesion. Segments of human coronary arteries without sclerotic damage demonstrated endothelium-dependent relaxation in response to activators of endothelial relaxation factor. Functional disturbance of coronary artery endothelium in endothelial relaxation factor production may be one of the causes of increased smooth muscle tonic contractions, responsible for coronary artery spasm underlying angina pectoris and myocardial infarction.

[Morphologic features of the endothelial lining of the blood vessels and endocardium]. / Morfologicheskie osobennosti éndotelial'noi vystilki krovenosnykh sosudov i éndokarda.

The endothelial lining (EL) of ventricular endocardium and coronary arteries of a dog, minipig and humans, as well as that of the abdominal aorta of a rat and superior vena cava (minipig) was studied using luminescent microscope in the reflected light after staining of the non-fixed tissue with thioflavine-T and argentation. Marked heterogeneity of the endotheliocytes was shown to be both specific and depending on the localization of the cells in the cardiovascular system. Comparative analysis of EL in different animal species and in man, as well as in different parts of the CVS, indicated the relationship between the cellular morphologic features and local hemodynamics.

[Rapid method of visualizing endothelium in unfixed tissue]. / Ekspress-metod vizualizatsii éndoteliia na nefiksirovannoi tkani.

An express method of visualization of endotheliocytes has been described. It is based on the combined use of vital dye-thioflavin and silver nitrate. The method requires no fixation, "häutchen" preparation and scanning electron microscopy. It is very simple, needs no special training or facilities and allows visualization of the endothelium already 2 min after the tissue is obtained.

[Presence of specific bradykinin receptors in arterial and venous smooth muscle]. / O nalichii spetsificheskikh retseptorov k bradikininu v gladkoi myshtse arterii i ven.

The relationship between bradykinin action and its concentration was examined on isolated rings of the rabbit aorta, femoral artery, jugular vein and on isolated strips of the rat portal vein. The sensitivity of femoral artery and portal vein smooth muscles to bradykinin was disclosed. Venous smooth muscles were more sensitive to bradykinin as compared with arterial smooth muscles. Dissociation constants for the rabbit aorta, femoral artery, jugular vein and for the rat portal vein were 3.98 X 10(-6), 6.3 X 10(-6), 1.26 X 10(-7), and 7.6 X 10(-9)M, respectively. Effects of endogenous bradykinin in vivo might result from its primary action on the venous smooth muscle, action on the arterial smooth muscle and veno-arterial interactions.

[Electrical and contractile activity of the myocardium during a change in temperature]. / Elektricheskaia i sokratitel'naia aktivnost' miokarda pri izmenenii temperatury

In rhythmically stimulated (0.05/sec) isolated strips of the ventricle myocardium of the fresh water fish, drop of the temperature (from 20 degrees C to 10 degrees C) increased the AP duration but decreased the extent of contractions; raise of the temperature (from 10 degrees C to 20 degrees C) increased the extent of contractions but decreased the AP duration. The discrepancy between the electric and the contractile activities points out the importance of processes of the transmembrane and intracellular redistribution of ions occurring at rest, for refilling of intracellular Ca deposit released during excitation.