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Iu M Vasil'ev

Publications and source records attributed to Iu M Vasil'ev.

12 recordsLinked to original sources
PubMed1979

[Cell rounding in variant sublines of the L line caused by a moderate decrease in temperature].

Several novel variants of mouse transformed L cells are described. A distinctive trait of these variants, isolated by different methods, is a rounding of the majority of cells under the influence of the moderate cooling (at 18 degrees C for 30-60 min). In the serum-free medium, no rounding occurs. The rounding is presumably an active contraction, because it is inhibited by cytochalasin B. The comparison of the phenotype of wild-type and variant cells has shown that the exposure of cultures at 18 degrees leads to a disturbance of cell adhesion to the substratum in both the cell lines. The intensive rounding of variant cells at 18 degrees is due to some defect in their attachment to the substratum, which can be revealed not only at 18 degrees, but also at 37 degrees. By the selection procedure described in this paper, a large group of cell variants defective in adhesion to the substratum may be isolated.

Animals↗
PubMed1979

[Morphology of the microtubule system in mouse kidney epithelial cells].

The cultured mouse kidney cells forming epithelial sheets were studied using an indirect immunofluorescence microscopy with antibodies against tubulin. These cells, as well as fibroblasts, were found to contain a well developed microtubular system sensitive to colcemid. The assembly of microtubules after washing out of colcemid began from one or two perinuclear centers, associated with the cilium-like structure. There were certain differences between the microtubular systems in epithelial cells and fibroblasts: 1) Microtubules in the fibroblasts penetrated the whole cytoplasm including the peripheral lamella whereas in the epithelial cells the lamellar cytoplasm was often free from microtubules. 2) The orientation of microtubules in the epithelial cells, unlike in the fibroblasts, was not correlated with the stable or active state of the cell margin. A possible role of microtubular system in the epithelial cells and fibroblasts is compared and discussed.

Animals↗
PubMed1978

[Effect of agents disrupting microtubules on the distribution of receptors on the surface of cultured cells].

Substrate-attached normal mouse fibroblasts, transformed mouse fibroblasts (L-strain) and epithelial cells (MPTR strain) were incubated with two ligands that are cross-linking different group of the surface receptors: concanavalin A and cationic ferritin. Surface-attached ligands were revealed by the indirect immunofluorescent methods. The incubation of control cells with these ligands induced a patching of corresponding surface receptors, and a clearing of these receptors from the surface zones located on the lamellar cytoplasm near the cell edges actively protruding pseudopodia. Effects of three antitubulins (colcemid, colchicine and vinblastin) on the ligand-induced redistribution of receptors were examined and compared with the previously described effects of these drugs on the distribution of active cell edges.

Animals↗
PubMed1977

[Effect of colcemid on the radial spreading of fibroblasts in culture].

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.

Animals↗
PubMed1977

[Effect of colchicine on polarization of cells on narrow strips of an adherent substrate].

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.

Animals↗
PubMed1975

[Processes determining changes in the shape of a cell following detachment from a substrate].

In contrast to living cells, glycerin extracted mouse embryo fibroblasts do not round up after detachment from the substrate. The addition of ATP makes these fibroblasts round up. Thus, the rounding of the detached cell occurs in result of active, ATP-requiring contractile forces rather than due to the action of elastic forces or of surface tension. The ATP-induced contraction of the glycerinated cell is accompanied with the loss of the parallel orientation of 50-70 A microfilaments. The loss is suggested to result from the attachment of different microfilaments of the same bundle to different points of the cell surface. Microtubules are not essential for the contraction: the rounding of living or glycerin-treated cells is not colcemide affected. Living cells treated with cytochalasine B (CH) reversibly lose their ability to round up after detachment. ATP is able to induce no contraction of glycerin-extracted cells treated with CH before extraction. In contrast, the addition of CH to the ATP-containing solution does not inhibit the contraction of glycerin-extracter normal cells. These results give reason to suggest that CH may inactivate contractile structures of the cell. It may be thought that some unknown additional factors, available in the living cell and not available in the glycerin-extracted one, are essential for this inactivation.

Adenosine Triphosphate↗
PubMed1975

[Insensitivity of stationary cultures of transformed mouse fibroblasts to agents stimulating DNA synthesis in normal cell cultures].

Stationary cultures of the mouse transformed cells L and S-40 sensitive to topoinhibition were found to be insensitive to the action of hyaluronidase, RNAase, and colcemid in doses known to stimulate multiplication of normal mouse fibroblasts. These cultures were still insensitive to the action of medium change and removal of a part of the monolayer.

Animals↗
PubMed1975

[Influence of intercellular contacts in epithelial sheets on the capacity of the cell surface for adhesion and phagocytosis of particles].

The influence of intercellular contacts on the ability of the upper cell surface to adsorb and to phagocytose particles was studied in different types of cultured cells of mouse origin. In cultures of the MPTR strain, cells formed firm contacts which remained unbroken during the epithelial sheet migration into the wound. The contact inhibition of phagocytosis was found in these cultures. The phenomenon involved a low phagocytic activity of the sheet cells which made intercellular contacts in all directions, and of high phagocytic activity of marginal cells which had activity moving free edges. Other epithelial cultures, such as explants of normal kidney and hepatoma 60, behaved similarly. Cultured embryo fibroblasts and hepatoma 22a cells did not form firm intercellular contacts and migrated into the wound one by one. In these cultures most cells had high phagocytic activity. It is suggested that the formation of intercellular contacts alters the upper cell surface ability to adhesion and phagocytosis of particles.

Animals↗
PubMed1975

[Highly permeable intercellular junctions in normal and transformed fibroblast cultures].

Intercellular junctions permeable to ions and fluorescein Na were studied with the aid of intracellular microelectrodes in the cultures of normal and transformed mouse-embryo and hamster-embryo fibroblast-like cells. Normal cells were effectively coupled by the highly permeable junctions. In cultures of 7 types of transformed cells, 3 types of coupling were detected: effective, decreased, and fully reduced couplings. The degree of uncoupling was not correlated with morphological patterns of malignization and tumorogeneity of transformed cultures. The decrease of permeability of intercellular junctions to ions and small molecules is concluded not to be necessary for malignization.

Animals↗
PubMed1975

[A method of measuring cell orientation].

A method is described for measuring cell nuclei orientation in culture. The nuclear orientation in the experiment was compared with that obtained in the model experiment with electronic computer. The method developed allows to compare nuclear orientation in parts of culture which differ both by area and number of nuclei. The method can be modified for measuring cell nuclei orientation with reference to the substrate relief. Examples are given of the method's application for comparing orientation of mouse embryonic fibroblasts and cells of the strain L.

Animals↗