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E A Zherbin

Publications and source records attributed to E A Zherbin.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Simulation modeling of the initiation of tumor growth in continually renewed cell systems].

A discrete stochastic model of simulation of a cell renewal system is discussed. The model is based on a functional approach to the present-day concepts on the nature of processes of cell proliferation and differentiation as well as mechanisms responsible for integration of these processes. Due to application of specialized programming means of simulation (language GPSS /360) a complete functional pattern of maintenance of cell-population homeostasis in tissue was reproduced. Disturbances in certain mechanisms of intra-tissue regulatory system accompanied by formation of tumor growth foci were simulated experimentally.

Animals↗
PubMed1982

[Separation of a rat thymocyte population in a ficoll-paque gradient. I. Relation of cell buoyant density to biological parameters].

Rat thymic cells were fractioned in the one-step Ficoll-Paque gradient. The three fractions obtained differed from one another with respect to average cell sizes, protein and DNA contents per cell. The light fraction cells revealed the maximum incorporation of labeled precursors into their nucleic acids, a relatively low hydrocortisone sensitivity and a diminished adhesion capacity. Following preincubation of thymus cell suspension and its gamma-irradiation, the number of the heavy fraction cells increased. The enrichment of the heavy fraction of cells with cortical thymocytes, including terminal ones, is supposed.

Animals↗
PubMed1982

[Separation of a rat thymocyte population in a ficoll-paque gradient. II. Dynamics of the cell count in different media and the effect of thymolytic factors].

Rat thymocytes were fractioned in the Ficoll-Paque gradient. Cells of various fractions were tested for their ability to survive in several nutritional media at 37 degrees C for 5 hours. In serum-less medium 199, the majority of cells died. The addition of bovine serum (10%) to medium 199 resulted in a sharp increase in the number of live cells in the light fractions. Again, the number of live cells in the light fractions was increased upon the 3 hrs-incubation in the serum-less medium containing hydrocortisone, as well as of cells obtained from animals previously injected with hydrocortisone. The X-irradiation of thymocyte suspension led to an obvious augmentation of the number of live cells, belonging to the medium fraction, after a 5 hours' incubation. A possibility is discussed of the increase in cell numbers of different fractions as the result of the "apoptotic" manner of their death.

Animals↗
PubMed1981

[Various biochemical and biophysical properties of a subpopulation of rat thymocytes isolated in a Ficoll gradient].

Subpopulations of rat thymocytes were obtained by cell precipitation in a single-stage transient phycoll gradient (isorapid precipitation). The fraction obtained were characterized in terms of the size, intensity of UV fluorescence, protein content and nucleoid mobility. The radius of thymocytes and UV fluorescence intensity monotonously increased during the transfer from the upper to lower fractions. The cells of medium-size fractions were characterized by the minimum content of cytoproteins and maximum mobility of nucleoid. In order to evaluate the density of thymocytes in the fractions, use was made of an additional cell precipitation in the phycoll-paque stage rho = 1.077. Incubation of thymocytes in medium 199 with a 10% rat serum led to the increased cell density in all the fractions, particularly in medium-size ones. Gamma-irradiation of thymocytes in a dose of 5 Gy appreciably accelerated the process under consideration. It is assumed that the medium-size fractions are enriched with thymocytes in G1 S phase, while lower fractions in G2 phase of the mitotic cycle. At the same time the fractions obtained appear to contain the subpopulations of thymocytes undergoing different stages of differentiation.

Animals↗
PubMed1979

[Cytogenetic effects induced by neutrons in human peripheral blood lymphocytes in vitro. I. Dose-effect relationship for different types of chromosome aberrations when exposed to neutrons with different energies].

Human lymphocytes were irradiated in vitro during G0 stage by graded doses of thermal neutrons and of neutrons with mean energy of 0.04; 0.09; 0.35; 0.85 and 14.7 MeV as well as by 60Co gamma-rays. The data were fitted to the linear and linear-quadratic relations. The neutrons of low and intermediate energies showed the linear dependence on the dose, 14.7 MeV neutrons and gamma-rays--a linear-quadratic one, whereas the data obtained with 0.85 MeV neutrons fitted well the both models. Terminal and interstitial deletions produced by both gamma-rays and neutrons showed different dependencies upon the dose. Some qualitative pecularities of aberration spectra were found in the experiments with neutrons as compared with the data on gamma-irradiation: the ratio of exchanges to fragments was greater, and aberrations of chromatid type were produced. The specially designed experiments and calculations showed that the last effect was not connected with induced radioactivity.

Cells, Cultured↗
PubMed1979

[Cytogenetic effects induced in vitro in human peripheral blood lymphocytes by neutrons. II. Relative biological effectiveness of neutrons having different energies].

Human lymphocytes were irradiated in vitro during Go stage by graded doses of thermal neutrons and neutrons having an average energy of 0.04; 0.09; 0.35; 0.85 and 14,7 MeV as well as by 60Co gamma rays, and RBE of neutrons relative to gamma-rays was calculated for the frequency of total and different types of aberrations. It was found that the RBE has the most value at the low doses and decreases when the exposition dose increases. 0.35 MeV neutrons have the maximum RBE in comparison with neutrons having other energies. When comparing the RBE values calculated for different types of chromosome aberrations, it was found out that dicentrics and dicentrics plus centric rings had more RBE than acentric aberrations (pair fragments and minutes).

Chromosomes, Human↗