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B A Korol

Publications and source records attributed to B A Korol.

7 recordsLinked to original sources
PubMed1993

The use of flow cytometry for the investigation of cell death.

Flow cytometry is more and more widely used for investigations of cell death, predominantly in the study of DNA degradation in cells dying by apoptosis. There are different interpretations of changes observed in DNA histograms of these cells. We describe an approach based on extraction of chromatin degradation products from fixed cells and subsequent staining with DNA specific dyes. Apoptotic cells containing fragmented DNA are observed in < 2C DNA region of DNA histograms. DNA histograms of irradiated thymocytes dying in vitro and stained without extraction of fragmented DNA do not differ from control. Under the same staining conditions DNA histograms of lymphocytes dying in thymus of irradiated animals reveal fluorescent material in < 2C DNA region, most likely due to formation of apoptotic bodies (cell fragments, some of them contain fragments of nuclei). Similar changes are observed in thymocytes dying upon glucocorticoid treatment. Our present results and other data indicate that reduced amount of DNA in dying cells is the main reason for changes of DNA histograms. Examples of application of the method described for the investigations of cell death modifiers are presented.

Animals↗
PubMed1986

Flow cytometry and biochemical analysis of DNA degradation characteristic of two types of cell death.

By flow cytometry it has been shown that in rat thymocytes dying upon gamma-irradiation the reduction in DNA content per cell occurs well before the increase in outer membrane permeability. In contrast, in irradiated Burkitt's lymphoma cells the disturbance of plasma membrane permeability precedes the decrease of DNA content. Genome degradation in dying thymocytes of irradiated or hydrocortisone-treated rats is accounted for by internucleosomal DNA fragmentation. Postirradiation DNA cleavage in the 3 investigated cell cultures is disorderly and is probably caused by the activation of hydrolases in dead cells.

Animals↗
PubMed1986

Flow cytometry analysis of DNA degradation in thymocytes of gamma-irradiated or hydrocortisone treated rats.

The pattern of DNA degradation in thymocytes of irradiated or hydrocortisone-treated rats has been studied by means of flow cytometry of the cells, treated with probes specifically bound to the AT or GC-pairs of DNA. It has been shown that the death of thymocytes is accompanied by a decrease in their DNA content. The main features of the occurrence and accumulation of cells with a DNA content less than the normal diploid level correspond with those of internucleosomal DNA fragmentation: such cells appear after a 1 hour lag-period, their accumulation is prevented by cycloheximide injection and is lower at 300 Gy than at doses of 10 to 30 Gy. At the same time, no increase in permeability of the cell membrane to ethidium bromide was observed up to the sixth hour after irradiation. Most of the thymocytes dying under the action of irradiation or hydrocortisone are in the G0 or G1 phases of the cell cycle. The method used allows detection of the cells with cleaved but not removed DNA.

Animals↗
PubMedDate not supplied

The effects of prenatal exposure to methylmercury on aggressive behavior in the rat.

The sensitivity of isolation-induced aggressive behavior to prenatal treatment of 6.0 mg/kg methylmercuric chloride (MMCl) by gavage on gestation days 6-9 was assessed in a subset of animals from the Collaborative Behavioral Teratology Study (CBTS). CBTS behavioral measures consisted of negative geotaxis, olfactory discrimination, auditory startle habituation, 1-hr activity, 23-hr activity, activity following pharmacological challenge and visual discrimination learning. Auditory startle was the only CBTS behavioral measure that discriminated among prenatal treatment groups. MMCl animals also were reliably more aggressive than vehicle controls in dyadic encounters. The results suggest that tests of aggressive behavior, which rarely have been included in teratologic assessments, be considered in the formulation of behavioral screening paradigms. The advantages of including tests of aggression and the relationship between aggressive and startle responses are discussed.

Acoustic Stimulation↗
PubMedDate not supplied

Collaborative Behavioral Teratology Study: results.

Behavioral measures used in the Collaborative Behavioral Teratology Study (CBTS) were negative geotaxis (PNDs 7-10), olfactory discrimination (PNDs 9-11), auditory startle habituation (PNDs 18-19 and 57-58), 1-hr activity (PNDs 21, 60, 100 and 120), 23-hr activity (PND 100), activity following a pharmacological challenge (PND 120), and an operant, discrete trial visual discrimination task. Maternal and offspring body weights and the appearance of certain physical landmarks of development were also monitored. The design of the CBTS allowed evaluation of the reproducibility and detection sensitivity of these behavioral test methods, as well as the impact of early testing experience on later behavioral assessment, offspring sex differences in response levels and variability, and the contribution of litter-to-litter and animal-to-animal variation to behavioral measures in a standardized test protocol. The results obtained in this test system are discussed in relation to each of these factors and to the degree of overt toxicity obtained using prenatal treatment with 0, 0.5 or 2.0 mg/kg d-amphetamine sulfate, SC, on gestation days 12-15 (Study 1) or methylmercuric chloride, 0, 2.0 or 6.0 mg/kg by gavage, on gestation days 6-9 (Study 2).

Age Factors↗
PubMedDate not supplied

[Cyclosporine A fails to prevent thymocyte death induced by ionizing radiation and hydrocortisone].

In experiments with albino mongrel mice the influence of cyclosporine A on thymocyte death in vivo under the effect of ionizing radiation and hydrocortisone has been investigated. The effect was assessed by the amount of soluble polydeoxynucleotides (PDN) that are formed in the cells. Dose dependence of the PDN yield and kinetics of their formation in thymocytes as well as electrophoretic mobility of PDN were studied after irradiation and the cyclosporine A treatment. Cyclosporine A was shown to have no effect on the thymocyte death induced by irradiation in vivo. The same results were obtained with hydrocortisone. Possible mechanisms of action of cyclosporine A on death of lymphocyte and proliferating cells are discussed.

Animals↗