[Effect of ionizing radiation on the chromatin fraction components in rat blood lymphocytes]. / Vplyv ionizuiuchoï radiatsiï na komponenty fraktsiï khromatynu limfotsytiv krovi shchuriv.

Changes in the level of blood lymphocyte chromatin degradation and relaxation were investigated after the whole body irradiation with doses up to 0.21 C/kg. It was shown that ionizing irradiation initiated the increase of nuclear endogenous Ca/mg-dependent endonuclease, and protease activities.

[Characterization of the nuclease-sensitive chromatin regions from N-nitrosodiethylamine-induced hepatoma cells]. / Kharakteristika nukleaza-chuvstvitel'nykh uchastkov khromatina kletok gepatomy, indutsirovannoi N-nitrozodiétilaminom.

Protein-DNA complexes released from chromatin of the intact rat liver and hepatoma induced by N-diethylnitrosamine during nuclease digestion have been subdivided into two groups of high and low molecular weight. Immunoreactive proteins are concentrated mainly in high molecular complexes. Immunoblotting of proteins from the nuclease-sensitive regions of normal and tumor chromatins allow distinguishing antigens of three main types: 1--antigens of nuclease-sensitive samples common both for normal and tumor cells; 2--antigens determined in tumor preparations only; 3--antigens usual for normal samples. Such differences in composition of immunogenic proteins in the nuclease-sensitive regions from the cells of the normal and malignant rat liver may be useful for investigating changes in active chromatin during chemical induction of tumors in animals.

[Immunogenic proteins of nuclease-sensitive regions of chromatin of the normal rat liver and N-nitrosodiethylamine-induced hepatoma]. / Immunogennye belki nukleaza-chuvstvitel'nykh oblastei khromatina normal'noi pecheni krys i gepatomy, indutsirovannoi N-nitrozodiétilaminom.

The localization of immunogenic proteins of chromatin in the nuclease-hypersensitive regions was investigated by means of polyclonal antibodies against the total chromatin from cells N-nitrosodiethylamine-induced hepatoma of rats and from hepatocytes. The fractions released after digestion by Ca-dependent endonuclease and by exogenous DNasa-1 were considerably enriched with immunogenic determinants. The enrichment of nuclease-hypersensitive sites of chromatin with tumour-associated antigens was observed in experiments with antihepatoma antibodies preincubated with chromatin from the normal liver cells. Higher immunoreactivity was typical of fractions obtained during Ca-dependent endonuclease segregation of the hepatoma chromatin, while products of digestion by exogenous DNasa-1 possessed higher tumour specificity.

[Immunogenic chromatin proteins of rat hepatoma induced by N-nitrosodiethylamine]. / Isseldovanie immunogennykh belkov khromatina gepatomy krys, indutsirovannoi N-nitrozodiétilaminom.

Immunoglobulins G against chromatin of N-nitrosodiethylamine-induced hepatoma of rats have been obtained. They help determining in the hepatoma tumour-associated chromatin proteins and proteins common for chromatins of the hepatoma and normal liver. Both tissue-specific and tissue-nonspecific proteins compose immunogenic chromatin proteins of the hepatoma.