[Influence of ionizing radiation on enzymatic activity and state of nucleus-nucleolar apparatus in rat hepatocytes].

The effects of a single exposure of rats to the whole-body roentgen irradiation at the doses of 3.5 Gy and 4.5 Gy on the activity of creatine kinase, purine nucleoside phosphorylase, alanine aminotransferase, aspartate aminotransferase, as well as on the state of the nuclear-nucleolar apparatus in rat hepatocytes on the 6th and 13th days after radiation exposure have been studied. Irradiation at the above doses induced changes in the levels of enzymatic activity of different values and different directions within the same time periods, as well as oscillating changes in this type of enzymatic activity over time. This demonstrates various radiosensitivity and adaptation abilities of these enzymatic activities. The changes in the enzymatic activity significantly correspond to the changes in the morphometric indices of nuclear-nucleolar apparatus of hepatocytes, as well as the distribution of hepatocytes within the ploidy classes: in particular, stabilization of the enzymatic activity on the 13th day after irradiation correlates with the increased transcriptional activity, which is detectable through the increased number of nucleoli per nucleus and the expanded space of a hepatocyte nucleus. The compensation mechanisms are likely to be targeted at the changes in the functional activity of surviving hepatocytes, rather than at the replacement of the damaged cells by the new ones.

[Pathology of lymphoid tissue cells infected by African swine fever virus in vitro].

The authors studied the pathology of bone marrow (BM) lymphoid cell from pigs infected by African swine fever virus (ASFV) in vitro. Monocytes were shown to be primarily afflicted in unstimulated BM culture. These cells disappeared completely 72 hours after infection. Just 24 hours following ASFV infection, there were atypical lymphocytes amounting to 12% of the general lymphoid population at hour 72 after inoculation.The area and perimeter of minor, middle, and large lymphocytes tended to reduce during both BM cell cultivation and inoculation. Lymphoblasts and monocytes were generally triploid in both the control and test groups, but among them there were diploid, triploid, and tetraploid cells. Cytophotometric assay revealed that the amount of nuclear DNA significantly increased in BM lymphoblasts and monocytes in the early stages of ASFV infection (within 24 hours). This effect was also rather pronounced in the lymphoblasts in the later stages (at hour 72).

[Immunocytophotometric and cytogenetic analyses of T-lymphoblastoid cell lines in experimental HIV Infection]. / Immunotsitofotometricheskii i tsitogeneticheskii analiz kletok T-limfoblastoidnykh linii pri éksperimental'noi VICh-infektsii.

The accumulation of viral proteins p24 and gp41 in MT-4 cells was shown to occur asynchronously. No increase in the number of polydiploid cells, no polyploid mitoses or chromosome defects were found indicating the antiproliferative effect of HIV on MT-4 cells. A cyclic pattern of the infection course was observed in infected Jurkat-tat cells. The accumulation of viral proteins was concerted, their maximum amounts preceding the cell death. HIV-1 did not inhibit cell division and caused strong disorders in the chromosome structure.

[Effect of dye quality and the method of preparing a Schiff reagent on the staining intensity and DNA-fuchsin absorption spectra in performing the Feulgen reaction]. / Vliianie kachestva krasitelia i sposoba prigotovleniia reaktiva Shiffa na intensivnost' okrashivaniia i spektry pogloshcheniia DNK-fuksina pri provedenii reaktsii Fël'gena.

Dependence of the staining and absorption spectra of DNA-fuchsin on the dye quality and modes of preparation of the Schiff-reagent was studied. It is shown that many dyes supplied by different producers do not suit the purposes of quantitative cytochemical investigations. Before use the absorption spectra of the DNA-fuchsin must be taken using the standard object. The use of dyes possessing a multi-peak absorption curve should be avoided.

[Intensity of the Feulgen reaction depending on the method and duration of fixation]. / Ob intensivnosti reaktsii Fël'gena v zavisimosti ot sposoba i prodolzhitel'nosti fiksatsii.

A comparative cytophotometric investigation of DNA-fuchsine content in mature erythrocytes of chicks was carried out using various methods and duration of fixation: 96 degrees and 100% ethanol, Carnoy's fixative, and mixtures of 40% formalin--96% ethanol--glacial acetic acid /GAA/(9 : 3 : 1), 100% methanol--4% formalin--GAA (17 : 2 : 1), and 96% ethanol--GAA (3 : 1)+formalin (final concentration 2%). The duration of fixation varied from 15 to 150 minutes, with 15 minutes intervals. It has been shown that the quantity of DNA--fuchsine (under equal conditions of the Feulgen reaction) depends greatly on the method and duration of fixation. Of the fixatives investigated the best is the mixture of 96% ethanol--GAA (3 : 1)+formalin 2%, after which the Feulgen reaction runs more intensively, and practically does not depend on the fixation duration. The structure of chromatin (determined by the distribution character of optical densities in each point scanned) is also best preserved. The Carnoy fixative occupies, by these parameters, the last place. The mechanisms of interaction of the above fixative with the nuclear DNP are discussed briefly.

[Effect of the hydrolyzing solution temperature, acid concentration and the duration of the hydrolysis on the intensity of the Feulgen reaction]. / Vliianie temperatury gidrolizuiushchego rastvora, kontsentratsii kisloty i prodolzhitel'nosti gidroliza na intensivnost' reaktsii Fël'gena.

The quantity of DNA-fuchsin in the cock monocytes and erythrocytes has been measured by scanning cytophotometric methods and computer analysis. Hydrolysis was carried out using 1 N HCl (60 degrees C, 4-30 min) and 5 N HCl (37 degrees C, 4-36 min, and 22 degrees C, 10-150 min). The elevation of the temperature from 22 degrees to 37 degrees resulted in a 5-fold reducing of the time required for achieving the maximum of the hydrolysis curve, although the DNA content at the maximum point decreased by 7-9%. At 60 degrees and 1 N HCl, the loss of DNA reaches up to 30%. The prolongation of the hydrolysis time caused even more losses of DNA: at 60 degrees they are equal to 70% (22 minutes following the maximum point), at 37 degrees it is equal to 55% (26 minutes) and at 22 degrees only 9.5% (100 minutes) (the quantity of DNA at the maximum point is taken for 100%). During all the experimental conditions and in both the cell types, the hydrolysis curves are monomeacked, and at 22 degrees starting from 30 minutes a plateau is observed with a slight increase towards the 50th minute. The quantity of DNA-fuchsin in the loose nuclei of monocytes is generally higher than in compact nuclei of erythrocytes. The analysis of scanning- and histograms has shown that the "storage" of DNA in the erythrocyte nuclei and its loss during hydrolysis are related to the fact that apurinization of DNA in the compact chromatin is getting more slowly, whereas its loss due to depolymerization-extraction is higher than in the loose chromatin. These phenomena are expressed least of all during "cool" hydrolysis. The above circumstances should be taken into account during the analysis of nuclei with different degrees of DNA density. Hydrolysis in 5 N HCl at 22 degrees is recommended.