[Supercarcinogens and supermutagens--nitrosoalkoxyalkylamines--effective producers of nitrogen oxide].

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.

[Lipoproteins as a factor regulating vascular tonus].

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.

[Endothelial relaxation factor as a local modulator of arterial function. The possibility of stabilization].

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.

[Morphologic features of the endothelial lining of the blood vessels and endocardium].

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.

[Endothelial function and spasm of the coronary artery].

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.

[Rapid method of visualizing endothelium in unfixed tissue].

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.

[Presence of specific bradykinin receptors in arterial and venous smooth muscle].

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.

[Electrical and contractile activity of the myocardium during a change in temperature].

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.