Biomedical subjects
Publications and source records attributed to Iu A Rovenskiĭ.
Explore the source record for details and available documents.
Five nontumorogenic cell lines suitable for vaccine production were studied by SEM. It was shown that diploid cell line 41 originated from sheep embryo kidney and also two heteroploid cell lines, line 4921 originated from embryo skin and muscles of the African green young monkey and line 4647 from kidney of the adult monkey, maintained normal cell morphology and normal growth pattern in early and in later passages in cultures. Some alterations in epithelial dense monolayer formation were revealed in the heteroploid cell lines: in line 455 originated from spleen of the adult African green monkey, and in line 4184 originated from line 41. The revealed alterations can be considered as the early morphological signs of the transformation of epithelial cells in culture. These cell lines also retained the stability of their morphological characteristics at the earlier and later passages. All the studied cell lines were free of contaminating agents.
Cells cultured on transparent conductive substrates (glass coated with indium oxide) were fixed with aldehyde and osmium tetroxide and then treated with tannic acid, uranyl acetate and lead citrate. The same cell culture preparation could be sequentially studied by light microscopy (in water immersed condition), SEM (after dehydration and critical point drying) and TEM (after embedding in an epoxy resin). This method ensures the preservation of intact cell morphology, cell surface topography and intracellular structures. The treatments used render the cells conductivity and permit to carry out successfully SEM of uncoated cells cultured on conductive substrates. This method also provides a higher contrast of TEM images.
The surface topography of resting (serum-deprived) and proliferating (serum-stimulated) NIH 3T3 monolayer cell cultures has been examined by scanning electron microscopy. During G1 and S periods of the cell cycle the cells exhibited well pronounced surface microvilli localized mainly in the perinuclear zone, whereas serum deprivation led to a relatively smooth surface with few microvilli. The observed differences are not likely to be associated with the degree of cell spreading over the substrate, rather reflecting metabolic peculiarities of proliferating and resting cells.
The ultrastructural properties of the cell surface of lymphocytes in cancer and polyposis of the stomach were studied with the help of rastrum electron microscopy. The cell surface of lymphocytes in gastric cancer was found to have specific morphological features which should be used as differential diagnostic criterion in gastric cancer.
Rat pleural mesothelium was studied 16 to 22 months after intrapleural inoculation of chrysotile-asbestos. Irregular diffuse hyperplasia and focal solid and papillary pretumoral lesions were found. The morphological picture of these lesions in SEM and light microscopy have been discussed.
Quantitative ratio of various types of cell surface microrelief was determined in suspensions prepared from mouse monolayer cultures of embryo fibroblasts grown on different solid substrates: with high (Falcon) or low poly(2-hydroxyethylmethacrylate) adhesiveness; with flat or cylindrical (53-mu curvature radius) surfaces (polyvinylchloride). The electron microscopy revealed that poorly spread cells (on low adhesive or cylindrical substrata) in suspensions had the microvillous surface relief much more often than the cells brought to suspension from highly adhesive or flat substrata. Thus, the lower the degree of cell spreading on the substratum, the higher the probability for the cell to acquire the microvillous relief in suspended state. The microvillous relief of transformed cells in suspensions is, probably, due to their poor spreading on substrata in the monolayer cultures.
The effect of cytochalasins B or D on the surface topography of mouse neoplastic fibroblasts of L line (detached from glass by trypsin-EDTA solution) or of its LS subline (adapted to the growth in suspension in vitro), as well as on that of Ehrlich's ascites tumor cells was investigated by screening electron microscopy. Incubation of suspended cells with cytochalasin B (2 micrograms/ml) or cytochalasin D (0.2 microgram/ml) for 30-180 min led to the following changes: (I) progressive decrease of the proportion of the cells with a microvillous surface relief and simultaneous increase in the percentage of the cells with a blebbed microrelief; (2) shortening of the microvilli and decrease of their density on the cell surface; (3) appearance of surface areas with a rough folded relief; (4) formation of very large blebs on the LS or L cell surfaces; (5) unusual "polar" distribution of blebs on Ehrlich's tumor and L cells: the blebs were concentrated in one locus on the cell surface. The data show that normal organization of the actin microfilament system in the cell cortex is necessary for formation of the microvilli but not for the blebs.
Continuous cell cultures are sensitive test systems used not only for the determination of the toxicity of diphtheria exotoxin, but also for revealing the toxic properties of adsorbed DPT vaccine. Morphological changes induced by the action of diphtheria exotoxin and adsorbed DPT vaccine in the cultures of L929, HeLa, FL, L132 and monkey tonsil cells are similar in character. The effect produced by the diphtheria exotoxin and adsorbed DPT vaccine on cell cultures may be characterized as toxic, subtoxic and minimal. Nevertheless, even in the cultures treated with minimal concentrations the pathological state of the cells can be detected in the next 2 or 3 serial subcultures.
The ultrastructure of superficial cells of the normal human cervical squamous epithelium and that in leukoplakia was examined by scanning and transmission electron microscopy. The characteristic appearance of normal cells is described. Changes in the concentration of tonofilaments and formation of keratohyalin granules were revealed in leukoplakia. Alterations in surface microridges were also observed. The latter phenomenon is closely related to a decrease in the number of tonofilaments at the cell periphery. It is possible that the altered microridges do not retain the cushioning protective mucin and maintain the stationary of progressive states of leukoplakia.
Quantitative analysis has shown that the cells of mouse ascites hepatoma 22a (AH-22a) possess a very low capacity for establishing steady contacts with various solid substrata (glass, carbon, collagen). This capacity considerably increased after the first formation of cell-substratum contact and was further enhanced as a result of repeated formations of such contacts (during the passaging of AH-22a cells in a monolayer culture). The effect observed was reversible since the cells of ascites tumour that developed in syngeneic mice after intraperitoneal inoculation of AH-22a cell culture rapidly lost previously acquired high capacity for adhesion to solid substrata. These modulations of cell adhesiveness are presumably related to reversible alterations in the cell surface.
Morphological peculiarities of spreading studied by scanning electron microscopy in two lines of transformed hamster fibroblasts (HETR and HEC--40) were compared to the normal hamster embryo fibroblasts (NHG). The surface of spherical not streading cells was of a mixed type microrelief (small blebs and microvilli). In transformed cells, the microvillous component was more developed than in their normal counterparts. During cell spreading distinct differences were observed between normal and transformed cells in their cell surface contact interaction with solid substratum. NHF cells formed a well-developed concentrically disposed thin lamelloplasm, while HEC-40 cells had asimmetrically disposed lamelloplasm in combination with long filopodia and HETR cells had a rather thick lamelloplasm consisting of several fragments (often forming star-like pattern). At the polarization stage of spreading neither HETR nor HEC-40 reached the same degree of spreading and flattening as NHF. Moreover, the dorsal surface of transformed cells had a complex microrelief in contrast to a rather smooth surface of NHF. These results are discussed in connection with earlier results on spreading of normal and transformed mouse fibroblasts.
To preserve the lifetime morphology of the surface of suspended cells, these must be fixed in suspensions. The subsequent stages of cell preparation for scanning electron microscopy (dehydratation, critical point drying, coating) are considerably facilitated if fixed cells are preliminary attached to some substrate surface. An effective substrate should provide a firm rather than selective attachment of the overwhelming majority of fixed cells; the substrate should be also available for a wide application. The trial of different types of substrates showed a sufficient effectivity of plates made of commercial aluminium foil. In tests with murine embryonal and transformed fibroblasts as well as with human blood leukocytes, in average 90 per cent of cells fixed with glutaraldehyde in suspensions got attached to foil substrate surfaces; the fixed cells both settled from suspension and attached were seen distributed evenly on the substrate surface. The use of aluminium foil substrates made it possible to study the surface topography of some types of suspended cells.
Reactions of cell nuclei on curvature of cylindrical surfaces (curvature radii 333, 75 or 61 mcm) in 9 lines of cultured transformed human, Syrian hamster, rat and murine fibroblasts were studied quantitatively. The nuclear elongation was assessed as a ratio of long to short axes. Contact orientation was characterized by values derived from the angles, formed by long nuclear axes with the direction of cylinder axis. Due to transformation, cells lost the ability to elongate their nuclei in response to cultivation on cylindrical surfaces. The ability of cells cultured on cylindrical surfaces to increase the contact orientation values was also lost or weakened considerably.
The quantitative estimation of migration ability of transformed fibroblast-like cells of various epecies (mouse , rat, hamster, man) cultured on the substratum with grooves of various depth (5--40 mcm) was performed. Of the majority of 11 cell lines examined, a reduced migration capacity up to its total disappeanance was registered as compared with the homological normal embryonic cells. A more pronounced reduction of migration ability was shown in mouse and rat transformed cells and less in human ones. Migration of transformed hamster cells was just equal to the weak migrtion of normal hamster embryonis cells. These data shown a weak response of the analysed transformed cells to the relief of underlying substratum.
Explore the source record for details and available documents.
Reactions to the geometrical configuration of the underlying surface of fibroblast-like cells of various species (mouse, rat, chick, hamster, human) were compared quantitatively. All normal cells migrated from 25-40 mcm deep grooves but not from the less deep ones -5-15 mcm. Migration ability was the highest in the mouse cells;it was less pronounced in rat and chick cells; hamster and human cells had the lowest migration ability. The offered quantitative method can be used for estimation of the reaction to the ordered relief of the substratum of different minds of cultured cells - normal as well as pathologically changed.
A simple modification of the critical-point drying apparatus is described. This modification was effectively used for preparation of normal and malignant cell cultures using the scanning electron microscopy.