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Biomedical subjects

A S Saenko

Publications and source records attributed to A S Saenko.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

[Factors affecting the DNA-binding activity of the blood serum in in patients and healthy persons at low ionic strength].

Interaction of blood serum proteins with native DNA at low ionic strength [0.05 M NaCl and 0.015 M sodium citrate], estimated by adsorption of DNA-protein complex on nitrocellulose filtrs, depended on specific activity, molecular weight of DNA as well as on the amount of DNA and blood serum in the samples. DNA-binding activity of blood serum from the patients should be estimated at such ratio of components, when the blood serum from healthy persons adsorbed minimal quantities of DNA, since the molecular weight and specific activity of the DNA preparations might vary in various samples. As a factor, regulating the rate of DNA binding on filtrs, such amount of blood serum from patients should be added to the samples, which corresponded to the maximal amount of normal blood serum causing no binding with the DNA preparations.

Adsorption↗
PubMedDate not supplied

[Immunochemical determination of DNA damage induced by high doses of ionizing radiation].

It was shown by the immunochemical method that DNA of X-irradiated E. coli cells of a radiosensitive mutant ABA88uvr A6 can react with the antiserum to thymine dimers which, in all appearance, are induced by ionizing radiation in bacterial DNA. The number of thymine dimers in DNA of E. coli AB1886uvr A6 increased with the dose increase. No dimers were detected in radioresistant cells of M. radioproteolyticus probably due to the effective excision thereof.

DNA, Bacterial↗
PubMedDate not supplied

[Experimental approaches in studying the biological properties and radiation sensitivity of human brain tumors].

The share of proliferating cells, the tumor growth fraction, was studied in 11 cases of glial tumors of the large hemispheres of man. The individual sensitivity of human glial tumors to irradiation was determined in 7 cases by the method of tumor growth in diffusion chambers. It was established that glioblastomas and dedifferentiated astrocytomas were characterized by a sufficiently high proliferative activity. The duration of the history of the disease and the period free of recurrences correlated with the value of the growth fraction in many cases. Gliomas, even of the same histostructure, differed considerably in the reaction to irradiation in some patients. The sensitivity of tumor cells to irradiation in growth in diffusion chambers does not depend on the proliferative activity of the initial tumors determined on operative material.

Animals↗
PubMedDate not supplied

[Adaptive response in vivo: reasons for increase of radioresistance in CFU-S].

The data concerning the reasons of CFU-S radioresistance increase after low dose irradiation of mice were obtained; the reparation processes in CFU-S adapted by low dose irradiation were shown to be more active than in intact ones. Colony formation increase was demonstrated to be more pronounced in adapted animals when they had been injected by 50 mcg of synthetic polyribonucleotide PolyI-PolyC two days before irradiation in challenge dose. The thymogen immunomodulator administration to adapted and intact donor animals leads to the increase of colony yield in equal extent.

Adaptation, Physiological↗
PubMedDate not supplied

[Radiation exposure of cultured tissue cells and animals (mice) within 10-kilometers zone of accident at Chernobyl nuclear plant. Effect on radiosensitivity to future radiation].

The effect of chronic low-level radiation exposure on radiosensitivity to posterior acute irradiation at high doses has been studied. Cells and mice were exposed within the ten-kilometer zone of Chernobyl disaster during various spaces of time (1-12 days), then over one or more days were additionally irradiated by doses of 1-4 Gy. It was shown that no adaptive response was developed under chronic exposure of cells and mice within the zone of disaster. On the contrary increased sensitivity to posterior irradiation was revealed. The number of cytogenetic damages of cultured tissue cells and marrow cells (chromosome aberrations and micronuclei) increases, the spectrum of aberrations being shifted to chromosome type, cells with multiaberration appearing. The decay of chromatine increases indicating an interphase death; the number of leucocytes in peripheral blood decreases.

Accidents, Occupational↗
PubMedDate not supplied

[Phenomenon of adaptive resistance to gamma-irradiation of colony-forming units (CFU-S): Manifestation in exogenous test].

Adaptive response of colony forming units in mice spleen (CFU-S) was investigated in exotest after preirradiation with doses of 0.3-5.0 sGy of 60Co. Adaptive radioresistance was manifested from 4 hours till 28 days after each challenge dose. Low dose rate preirradiation is less effective as adaptive response inducing action than high dose rate one.

Animals↗