[The effect on the cerebral microcirculation of in vivo stains used in biomicroscopy]. / Vliianie na mikrotsirkuliatsiiu mozga nekotorykh prizhiznennykh krasitelei, ispol'zuemykh pri biomikroskopii.

Vasoactive properties of semi-colloidal acid stains of the Evan blue and tripane blue, were revealed in rabbits and rats. The microphoto-technique revealed a dose-depending vasodilating effect of the stains. The response of the arteries had sometimes a biphasic character: constriction--dilation. I. v. administration of the stains induced a dose-dependent significant reduction of local blood flow in the cortex, subcortical white substance and other parts of the brain, of total cerebral blood flow in the venous sinus; a drop of systemic arterial pressure in normo- and hypertensive animals; a change in cerebral bioelectrical activity with increasing theta-waves, appearance of spikes and polyspikes in the EEG. Acting upon the formation of vascular tonus, these stains can interfere with the mechanisms of regulation of cerebral blood flow.

[The morphological changes in a primary culture of 3-day-old rat hepatocytes cultured over 1 week and in a model of anoxia]. / Morfologicheskie izmeneniia v pervichnoi kul'ture gepatotsitov 3-sutochnykh krys pri kul'tivirovanii v techenie 1 nedeli i modelirovanii anoksii.

A direct observation of primary cultures of 3-day-old rat hepatocytes was performed with the help of time-consuming cinematography. The process of monolayer formation has been examined. In addition, the continuous preservation of bile canaliculi was observed. A significant increase in hepatocyte mobility was marked in 6-7-day cultures. The structural analysis of cultured cells during the modelling of anoxia with substrate deficiency revealed a succession in hepatocyte and fibroblast alterations. The hepatocyte destruction was accompanied with changes in the cell form, that become rounded, and in the appearance of small formations protruding on the cell surface. The fibroblast destruction appeared after cell contracture.

[Status of the "dead point" of blood flow in anastomoses of superficial cerebral arteries as affected by an acute increase of blood pressure]. / Sostoianie "mertvoi tochki" krovotoka anastomozakh arterii poverkhnosti mozga pri ostrom pod"eme arterial'nogo davleniia.

Changes in pial arteries diameter and the condition of blood flow "dead point" in arterial anastomoses were established using the brain window during an acute increase of mean arterial pressure (MAP) induced by intravenous injection of norepinephrine (NE) with microcineangiography and the analysis of films and frames on a montage table and TAS ("Leitz"). During an acute increase of MAP the movement of blood flow "dead point" in anastomoses and the expansion of plasma segments occurred much more frequently than in normotension. The stabilization of blood flow "dead point" was observed at high constant MAP. Pronounced dilation of both pial arteries and veins first occurred in anastomoses, then spread to arterial branches. It is assumed that high vulnerability of the brain vessels of the borderline zones is due to breakthrough in autoregulation of cerebral blood flow on its upper limit and depends on the repeatedly changing directions of the blood flow and its moving "dead point", as the peripheral resistance of arterial anastomoses-forming branches under these circumstances changes in an irregular manner.

[Mechanisms of cellular multinucleation as affected by cytochalasin B in a culture of transformed fibroblasts]. / Mekhanizmy obrazovaniia mnogoiadernykh kletok pod deistviem tsitokhalazina B v kul'ture transformirovannykh fibroblastov.

The multinucleation of cytochalasin B was studied by means of phase contract microscopy and time-lapse cinematography. Several types of alteration of normal cytokineses resulted in the formation of multinucleated cells. The main way of multinucleation consists in the complete development of a cleavage furrow with the formation of daughter cells and an intercellular bridge that is followed by the fusion of these cells due to extending the entercellular bridge. These results suggest that the terminal stage of cytokinesis is the most sensitive to cytochalasin B.

[Contact interactions of epithelial layers]. / Kontaktnye vzaimodeistviia épitelial'nykh plastov.

Cultured together epithelial cells of mouse kidney (line MPTR) were seen to form a mixed cohesive sheet. The mutual interaction of different cells in the sheet was studied by phase contrast microscopy, time-lapse microcinematography, scanning electron microscopy and by some other morphological tests. The upper surface of the mixed sheet was continuous on the border of the two cell types. Despite this border between different cell types was continuously moving from FBT towards MPTR, as if MPTR was "pushed aside" by FBT. In some cases such a moving caused a total exclusion of MPTR from the sheet. Excluding cells differed from the excluded ones in their better spreading and better adhesion to the underlying substrate. Possible mechanisms of such an exclusion are discussed.

[Microtubule-independent cell surface stabilization in normal and transformed connective tissue cells]. / Nezavisimaia a ot mikrotrubochek stabilizatsiia kletochnoi poverkhnosti u normal'nykh i transformirovannykh soedinitel'notkannykh kletok.

Effects of colcemid on the distribution of pseudopodial activity in both normal and transformed connective tissue cells was studied by means of phase contrast microscopy and time-lapse cinematography. It was shown that normal as well as transformed fibroblasts are able to stabilize their surface independently on the presence of colcemid, however, in transformed cells this ability is more expressed. Possible mechanisms of this stabilization of cellular surface, independent on microtubules is discussed.

[Effect of colchicine on polarization of cells on narrow strips of an adherent substrate]. / Vliianie koltsemida na poliarizatsiiu kletok na uzkikh poloskakh adgezivnogo substrata.

Effect of antitubulin colcemide on polarization of mouse fibroblast-like cells on anisotropic substrate was studied. Such a substrate was obtained by scratching narrow strips in lipid films, adsorbed on the glass. The control cells were seen spread only along the strips, and in 4-6 hours they approached the length of120-150 mcm. In colcemide-containing media, the cells remain in an unspread state for a long time; they extrude their outgrowths both along the strip and perpendicularly to it. Due to frequent refractions of outgrowths, two thirds of colcemide-treated cells were detached from the substrate. Possible mechanisms of these effects of antitubulins are discussed.

[Effect of colcemid on the radial spreading of fibroblasts in culture]. / Vliianie koltsemida na radial'noe rasplastyvanie fibroblastov v kul'ture.

Effect of colcemide upon the spreading of mouse embryo fibroblast-like cells on the substrate was studied with the aid of time-lapse microcinematography and scanning electron microscopy. On the glass, colcemide did not prevent the transition of cells into a well-attached state, however, the time needed for this transition was seen considerably increased as compared with the control cultures. Intermediate stages of spreading on flat glass had the following abnormal features in colcemide-containing medium: a) shapes of cytoplasmic outgrowths formed by the cell were altered and their distribution along the cell border appeared less regular; b) partial detachments of the attached parts of cells occurred very frequently; c) the spreading of various parts of the cells was not correlated. Possible mechanisms of colcemide action on the cell spreading are discussed, and it is suggested that intracellular structures sensitive to colcemide are essential for coordination of reactions that occur in various parts of the cell in the course of spreading.