[Metal-binding capacity of metallothioneins of the liver of rats poisoned with heavy metals].

The functioning of metallothioneins in the liver of rats, poisoned with copper sulfate and cadmium sulfate has been investigated. By sequential chromatography on sephadex G-50 and DEAE-cellulose the authors obtained metallothioneins (MT-1, MT-1A, MT-2, MT-2a), which differ in molecular weight and composition of associated metals. Heavy metal poisoning leads to activation of synthesis and metal-binding function of metallothioneins, as well as to changes in the composition of their isoforms.

[Effect of irradiation on the degradation of rat thymocyte chromatin].

Genome instability of adaptive nature is formed under the experimental influence on a cell. Under critical conditions, strategy of organism is to damage the cells that cannot be restored and controlled by including the program of apoptosis. The ordered internucleosomal DNA degradation is considered to be one of the proof attributes of immunocompetent cell apoptosis.

[Determination of DNA damage in nonproliferating animal cells].

The modification of precipitation method for detecting DNA damage in mammalian cells using fluorimetric assay with 3.5-diaminobenzoic acid has been suggested. This modification allows determining DNA single- and double-strand breaks in mammalian nonproliferating cells and tissues.

[The possibility of using the preparation MIGI-K in districts exposed to radioactive contamination following the accident at the Chernobyl AES].

A preparation from mussels, MIGI-K, used as an additive to the diet of people working at the Chernobyl power plant has proved to be efficient in increasing the total resistance of the body, including the resistance to ionizing radiation. In experiments with animals, MIGI-K has been shown to accelerate excretion of 45Ca and 86Rb from the body. The combination of these properties of MIGI-K permits us to consider it an efficient drug to be used within the regions affected by the Chernobyl disaster.

[Activity of antioxidant system enzymes and lipid peroxidation product content in the liver and thymus of rats in the early stages of irradiation].

The activity of enzymes of the antioxidation system and the content of some lipid peroxidation products in the liver and thymus of irradiated (0.21 C/kg) rats have been investigated. Glutathione reductase and glutathione transferase activity in the liver and thymus of rats decreased during the first 24 h after irradiation.

[Changes in the intensity of DNA synthesis in immunocompetent mouse tissues by peptidoglycans of bacterial origin].

The data are presented on the effect of activation of by peptidoglycans from cell walls of Staphylococcus aureus and Brevibacterium flavum on the DNA synthesis intensity in the mice spleen, thymus and bone marrow in vivo. Maximum of the peptidoglycan influence on the DNA synthesis intensity is observed 12-36 hours after injection. As a rule, higher doses of the studied peptidoglycans (1 mg per one animal) activate the DNA synthesis more efficiently.

[Kinetic characteristics of Ca2+-phospholipid-dependent protein kinase from the rat liver in the early stages after x-ray irradiation].

The changes of kinetic characteristics (apparent Km and Vmax) of the Ca2+ phospholipid-dependent protein kinase (protein kinase C) from the rat liver for substrates ATP and histone Hl 2 and 24 hours after total X-ray irradiation have been established. The obtained results evidence for the important role of these changes in early radiosensitivity of protein kinase C.

[The biological effects in animals in relation to the accident at the Chernobyl Atomic Electric Power Station. 7. The content of lipid peroxidation products and free fatty acids and the catalase activity in a number of organs and tissues of rats].

The content of malonic dialdehyde, dienic conjugates and free fatty acids, and catalase activity were determined in some organs and tissues of chronically irradiated rats. Certain regularities were found in lipid metabolism changes. The MIGI-K preparation was shown to normalize some indices under study.

[The content of phospholipids and free fatty acids in the sarcoplasmic reticulum membranes in the early stage of an x-ray radiation lesion].

One and 24 h following single X-irradiation (0.21 C/kg) of rabbit hind leg the content of free fatty acids and phospholipid lysoforms increased in the sarcoplasmic reticulum (SR) membrane of skeletal muscles. The results obtained are important in estimating the mechanisms of action of ionizing radiation on the structural and functional properties of SR.

[Electrogenic activity of Ca2+-ATPase fragments of the sarcoplasmatic reticulum during the early stages of radiation injury].

It is established that local X-ray irradiation of the rabbit hind limb produces a decrease in Ca2+, Mg2+-ATP-dependent formation of electric potentials difference on the membrane of the sarcoplasmic reticulum (SR). These results agree with the observed decrease in the Ca2+-ATPase activity of SR membranes and increase in their electric conduction after irradiation.

[Study of the effect of phosphorylation of histones on their interaction with DNA-cellulose].

Data about the influence of phosphorylation levels of histones isolated from the prereplicative and replicative phases induced to proliferation by cycloheximide of rat hepatocytes, on their interaction with DNA-cellulose are presented. It is shown that the DNA-cellulose chromatography of histones is a sensitive model for the investigation of the effect of phosphorylation of histones on their electrostatic interaction with DNA. Using this method it is possible to separate high-phosphorylated subtype of rat liver H1 histones from other subtypes and also to show a direct dependence between the phosphorylation levels of histones and stability of their binding with DNA in prereplicative and replicative phases not only under conditions of proliferation induction by cycloheximide, but also under the subsequent influence of X-irradiation and serotonin.

[Effect of irradiation on the intensity of chromatin protein synthesis in the rat liver during protection with serotonin in pulsed inhibition of translation by cycloheximide].

The model of impulse translation inhibition by cycloheximide in the rat liver was used for studying the combined and separate effect of serotonin and irradiation on the intensity of synthesis of chromatin proteins (histones and nonhistone proteins). Irradiation induces a considerable inhibition of the protein synthesis intensity, while serotonin has a contrary action, that under conditions of subsequent irradiation provides an increase in the synthesis level of histones and nonhistone proteins. Possible mechanisms of the irradiation and serotonin effect on the synthesis processes of chromatin proteins in the organism are discussed.

[Cyclic nucleotide levels in the regenerating liver of rats following irradiation and protection by serotonin].

Changes in cAMP and cGMP levels after X-irradiation and radioprotective treatment with serotonin were studied using a model of impulse inhibition and repair of transcription, translation and replication by cycloheximide in rat hepatocytes in vivo. Irradiation was shown to inhibit the cyclic nucleotide synthesis. Serotonin increased the contents of cAMP and cGMP maintaining their elevated level after X-irradiation.

[Isolation and purification of histone-specific acetyltransferases from the rat liver].

There forms of histone-specific acetyltransferases--A, B and C are obtained from the rat liver nuclei. The isolation process included nuclei generation, ammonium sulphate salting-out of proteins, DEAE-cellulose, hydroxyl-apatite, phosphocellulose chromatography and Sephadex C-200 gel-filtration. Acetyltransferases A, B and C from the nuclei were purified 56.

[Synthesis and phosphorylation of histones and nonhistone proteins as affected by irradiation and serotonin in cycloheximide-synchronized hepatocytes].

Phosphorylation and synthesis of histones and nonhistone proteins were studied after the inhibition of translation by sublethal cycloheximide doses. Activation of the chromatin protein phosphorylation was noted: (1) at the stage of recovery and stimulation of the protein synthesis (18-24 h), and (2) at the stage of activation of the replicative DNA synthesis (30-60 h). Phosphorylation and synthesis of the chromatin proteins depended upon the individual or combined effect of X-radiation and serotonin.

[DNA synthesis in the liver of irradiated and serotonin-protected rats after removal of the cycloheximide block].

The cycloheximide block model was proposed to study the mechanism of action of both radiation and radioprotectors. It was shown that irradiation of proliferating hepatocytes in vivo, at early stages of the prereplicative phase, markedly inhibited DNA synthesis. Serotonin, in its turn, considerably increased DNA synthesis maintaining this increase after subsequent exposure to X-radiation.

[Effect of cAMP accumulation activators on the individual stages of genome expression in cells in acute radiation injury. 6. Inhibition of RNA synthesis on a template of isolated chromatin by separate histone fractions from the liver of normal, irradiated and serotonin-protected rats].

Using an acellular system, with isolated chromatin as a template, and E. coli RNA-polymerase it was shown that irradiation of rats with a lethal dose (7.76 Gy) caused a progressing, in time, decrease in the inhibitory effect of H1, H2a, H2b, H3 and H4 histones (particularly H2a histone) on RNA synthesis.

[Effect of serotonin on chromatin protein methylation in radiation injury].

The paper deals with the influence of the X-irradiation and serotonin, as a radioprotector, on the chromatin protein methylation. It is shown that the X-irradiation and serotonin cause changes in the intensity of chromatin protein methylation in vivo, that may be explained by their effect on the activity of the corresponding methylases. Possible relationships between the changes in methylation of chromatin proteins and the general response of the organism to the irradiation, including administration of the radioprotector is under discussion.

[Adenylate cyclase system and structural modifications of nuclear proteins in organisms radioprotection].

The paper deals with modern ideas of ways and mechanisms for realization of the radioprotector antiradiation effect. The data on the effect of biogenic amines (serotonin in particular) and radiation on the cAMP system are analyzed. It is shown that one of the most important mechanisms of the radioprotective effect is realized by changing the levels of histones and nonhistone proteins modifications through the adenylate cyclase system which leads to regulation of the chromatin template activity.