[Cytotoxic and cytogenetic effects of radiation are modulated by introduction of RNA preparations obtained from various body tissues]. / Izemenenie tsitoksicheskogo i tsitogeneticheskogo éffektov radiatsii pri vvedenii v organizm preparatov RNA, vydelennykh iz raznykh tkanei.

We studied the influence of various gamma-ray doses on the death pattern of Wistar rats and the changes in lethality after introduction of RNA isolated from various tissues in the organism. All studied RNA introduced into the irradiated animals proved to clearly stimulate repair of the cells damaged by radiation and to decrease both cytotoxic and cytogenetic effects of gamma-rays. The most pronounced effect on the cells was specific for RNA isolated from the matching tissue.

[Modification of the mutagenic effects of gamma radiation by heavy metal salts]. / Modifikatsiia mutagennykh éffektov gamma-izluchenii soliami tiazhelykh metallov.

The effect of K2Cr2O7 and (CH3COO)2Pb on the mutagenic activity of gamma rays was studied by a micronucleus test in mouse bone marrow polychromatocytes. Acute and chronic combined actions of the two factors were investigated. Chromium ions (VI) enhanced mutagenic effects of gamma rays in both acute and chronic experiments. In the acute experiments lead ions (II) below 15 mg/kg body weight decreased the number of gamma-ray-induced micronuclei, while higher doses increased it. Chronic combined action of lead ions (III) and gamma rays inhibited mutagenic activity of radiation.

[Specifics of changes in various groups of enzymes in rat cerebral cortex after interstrain transplantation of embryonal nerve tissue]. / Spetsifika izmenenii raznykh grupp fermentov v kore mozga krys posle mozhlineinoi transplantatsii émbrional'noi nervnoi tkani.

Embryonal nervous tissue from Wistar rats was transplanted into male rats of Wistar and August strains. Activity of eight enzymes belonging to various systems was estimated in brain cortex of rats recipients within 36 days after the transplantation. Lactate dehydrogenase, alanine aminotransferase, acid phosphatase, 5'-nucleotidase, ATPase and aldolase exhibited the dissimilarly decreased rate of activity in brain cortex of Wistar rats after transplantation as compared with the enzymatic activity in intact animals of this strain, while activity of alkaline phosphatase and esterases hydrolyzing alpha-naphthyl acetate was increased. Activation of almost all the enzymes studied was found within 36 days in Wistar rats after the transplantation. The rate of activity of zonal esterase isoenzymes was higher in brain cortex of August rats after transplantation of embryonal nervous tissue from Wistar strain as compared with that of Wistar to Wistar rats transplantation. The data obtained suggest that tissues of donors affected definitely the enzymatic activity in brain cells of rats-recipients as activity of most enzymes studied was higher in brain cortex of donors as compared with that of recipients.

[Changes in the esterase activity and isoenzyme spectrum following the transplantation of embryonic nerve tissue into the brain of adult rats]. / Izmenenie aktivnosti i izofermentnyi spektr ésteraz posle transplantatsii émbrional'noi nervnoi tkani v mozg vzroslykh krys.

Nervous tissue of 17-days old rat embryos was transplanted into lateral ventricle of the brain of adult rats. 15 days after transplantation esterase activity was analyzed from transplant tissue and flanking regions of cerebral cortex. Isoenzymes were shown to activate their activity after embryonic tissue transplantation either in transplants or flanking regions. These changes result obviously from the effect of substances, synthesized by transplant.

[Changes in the activity of different classes of enzymes in the cerebral cortex of rats in ontogeny and after the transplantation of embryonic nerve tissue]. / Izmenenie aktivnosti raznykh klassov fermentov v kore mozga krys v ontogeneze i posle transplantatsii émbrional'noi nervnoi tkani.

The activity of lactate dehydrogenase (LDH), indophenol oxidase, aspartate aminotransferase (AsAT), alkaline phosphatase, acid phosphatase and aldolase at different stages of rat development was measured. We have also determined changes in the activity of these enzymes resulting from transplantation of embryonic nerve tissue (ENT) into the brain of adult animals. During development from the embryo to the adult animal, LDH and AsAT activities increased, while alkaline phosphatase activity diminished. After ENT transplantation, the most prominent changes were in the alkaline phosphatase activity whereas the activity of LDH, AsAT and acid phosphatase remained unchanged and similar to that in the brain cortex of intact adult animals. Changes in the enzyme activity resulting from ENT transplantation changed in a manner characteristic of the transplant. Local brain damage did not change the activity of the studied enzymes fifty days after surgery.

[14C-adenine incorporation into neurons and glia of the cerebral cortex of rats after hypoxia and transplantation of embryonal nerve tissue]. / Vkliuchenie [14C]-adenina v neirony i gliiu kory golovnogo mozga krys posle gipoksii i transplantatsii émbrional'noi nervnoi tkani.

Incorporation of 14C-adenine (imp/min per mg) into RNA of brain tissue and into fractions of neurones and glial cells of cerebral cortex was studied rats with diffuse damage (hypoxia), with local injury of brain tissue and after transplantation of embryonal nervous tissue. The diffuse damage decreased a number of cells in the fraction enriched with neurones and, therefore, diminished incorporation of the marker into the whole preparation. No significant changes was found in a number of glial cells. Uptake of adenosine per mass unit of glial RNA was increased, while it remained unchanged in neurones. Local injury of cerebral cortex simultaneously with hypoxia resulted in an increase of cells amount in the fraction of neurones. At the same time, incorporation of the marker into RNA of both neurones and glial cells was increased. Transplantation of embryonal nervous tissue into cortex of adult rats with hypoxia normalized the ration neurone/glia as well as the rate of the marker incorporation into glial cells and neurones.

[The short-term and long-lasting changes in DNA and RNA synthesis in the cerebral cortex cells of animals subjected to hypoxia and nerve tissue transplantation]. / Kratkovremennye i dlitel'no sokhraniaiushchiesia izmeneniia sinteza DNK i RNK v kletkakh kory mozga zhivotnykh, podvergnutykh gipoksii i transplantatsii nervnoi tkani.

The DNA and RNA synthesis in the cells of the brain cortex of intact rats and animals subjected to hypoxia, hypoxia with subsequent transplantation or by the local brain injury has been investigated. The DNA synthesis changes insignificantly in the case of hypoxia, it enhances slightly in the area of the injury and increases much more after transplantation. The RNA synthesis decreases considerably immediately after hypoxia and decreases much more 120 days later. Using the ultracentrifuge method it has been found that under the effect of hypoxia the number of nervous cells decreases, the number of glial cells does not change. The local injury in the nervous tissue enhances abruptly the synthesis in neurons and glial cells in the hypoxia-exposed animals, the embryonic nervous tissue transplantation normalizes the number of neurons in the specimens under study and the RNA synthesis in the neurons and glial cells.

[Quantitative and qualitative changes in protein biosynthesis induced by hypoxia and transplantation of embryonic nerve tissue into the brain of adult mammals]. / Kolichestvennye i kachestvennye izmeneniia biosinteza belka, vyzvannye gipoksiei i transplantatsiei émbrional'noi nervnoi tkani v mozg v vzroslykh mlekopitaiushchikh.

The changes in biochemical processes in brain cortex in rats with experimental hypoxia and hypoxia with consequent transplantation of embryonic nervous tissue into brain of adults have been studied. A small increase (2-3 times) in incorporation of biosynthesis precursors was observed as a result of transplantation both in normal and in hypoxic rats. These changes could be observed 100 days after the transplantation. These changes in biosynthesis led to selective increase in the amounts of 40-45 and 35-39 kDa proteins, which are characteristic both for local trauma caused by transplantation and for general one caused by hypoxia. The effect observed may be explained as a reaction of nervous cells on damage, and not on the presence of an embryonic brain transplant.

[Isolation and study of the properties of a protein factor activating proliferative processes in nerve tissue]. / Vydelenie i izuchenie svoistv belkovogo faktora, aktiviruiushchego proliferativnye protsessy v nervnoi tkani.

The method of isolation and some properties of the neutral protein activator of proliferation processes are described. The protein obtained is characterized by high lability and easily destroys treated with proteolytic enzymes and stored under any conditions. It loses the greater part of activity. Peptides formed differ in their properties from the proliferation peptide activators studied earlier and are not able to stimulate the proliferation processes in the brain tissue cells.

[Study of DNA synthesis stimulators in nerve tissue cells]. / Issledovanie stimuliatorov sinteza DNK kletok nervnoi tkani.

Ontogenetic changes in DNA synthesis in different divisions and regions of the brain occur via different mechanisms, which is conditioned by changes in the composition and properties of corresponding mediators. Tissue extracts obtained from the parts of brain characterized by intensive cell division (cortex of 15-17-day-old embryos or cerebellum of 8-10-day-old animals) can stimulate the incorporation of labeled precursors into brain cell DNA in both neonatal and adult rats. Using desalting at increasing concentrations of ammonium sulfate, gel filtration on sephadexes and isoelectrofocusing, three fractions of DNA synthesis stimulators whose isoelectric points lie at acidic, neutral and alkaline regions of pH, were isolated. A method is described, which can be employed for isolation in a pure state and determination of some physico-chemical properties of an acid activator. The latter is a low molecular weight peptide causing marked stimulation of [3H]thymidine incorporation into nervous tissue cell DNA in an in vitro system, when taken at a concentration of about 1 microgram/ml.