[The role of plant compounds in the prevention of oncologic diseases]. / Rol fitosoedinenii v profilaktike onkologicheskikh zabolevanii.

The paper presents summarized data on numerous biologically active compounds found in plants. Their anticancer preventive potential is analyzed as well as possibility of their use to stimulate anticancer resistance of the body. Antimutagenic, anticarcinogenic, immunomodulating and other characteristics of organic and inorganic compounds of plant origin are considered in detail. Carotinoids, tocopherols, polyphenols, etc. are examined for the preventive potential against cancer. Some compounds and plant extracts are believed influential in initiation, promotion and progression of malignant tumors.

[Antimutagenic properties of substances containing beta-carotene]. / Antimutagennye svoistva preparatov, soderzhashchikh beta-karotin.

Two carotene-containing drugs (natural and artificial) were shown to decrease the rate of chromosomal aberrations, induced by cyclophosphane, in bone marrow cells of mice, daily ration of which contained 10-20 mg/kg of beta-carotene within 1-3 weeks. The rate of chromosomal aberrations induced was decreased 1.5-2-fold in various experiments. Artificial beta-carotene exhibited aftereffect within at least 3 days, while its protective effect was decreased about by 20% within 7 days after administration.

[Development of substances for active prevention of cancer based on vitamins and preventive-treatment products]. / Razrabotka sredstv aktivnoi profilaktiki raka na osnove vitaminnykh preparatov i lechebno-profilakticheskikh produktov.

The conception and program are described for development of drugs involved in active prophylaxis of malignant neoplasms. Development of prophylactic drugs and new treatment-prophylactic food-stuffs was shown to be possible and expedient to use toxic immunomodulators and natural anticarcinogens. Complex drugs are assumed to include carotenoids, tocopherols, water-soluble vitamins, polysaccharides and other biologically active substances exhibiting anticarcinogenic, antimutagenic and immunostimulating properties. New treatment-prophylactic food-stuffs are developed using milk protein concentrates, lyophylized cruciferous and vegetable juices and extracts of medicinal herbs. The work is realized in the research association involving academic, branch and educational institutions according to State priority programs.

[Relation between DNA replication and neutral Mn 2+-dependent DNAse activity in chromatin]. / Zavisimost' replikatsii DNK ot aktivnosti neitral'noi Mn 2+-zavisimoi DNKazy khromatina.

In cultures of primary murine fibroblasts the 10% serum stimulates the replicative synthesis of DNA inhibited by aphidicolin and araC (cytosine arabinoside). Using direct immunofluorescence analysis, it was shown that antibodies penetrate inside the cells and after 4 hours are pooled in the nuclei, where they remain for another 20 hours. The substitution of antibodies against chromatin DNAase by bovine serum albumin of normal serum gamma-globulins does not interfere with the DNA synthesis induction.

[Stimulation of DNA synthesis in isolated nuclei of rat liver cells by neutral Mn-dependent DNase of chromatin]. / Stimuliatsiia sinteza DNK v izolirovannykh iadrakh kletok pecheni krys netral'noi Mn-zavisimoi DNKazoi khromatina.

It was demonstrated that neutral Mn-dependent DNAase from rat liver chromatin stimulates the incorporation of labeled precursors of DNA into high molecular weight fractions of isolated nuclear DNA. The effects of DNA-polymerase inhibitors and the properties of DNA synthesis products suggest that neutral Mn-dependent DNAase can induce replicative synthesis of DNA in the nuclei of normal and regenerating rat liver.

[Ability of virus SV40 T-antigen to simulate the effect of specific T lymphocyte growth factor--interleukin-2]. / Sposobnost' T-antigena virusa SV 40 zameniat' deistvie spetsificheskogo rostovogo faktora T-limfotsitov--interleikina-2.

The entering of T-lymphocytes into the DNA-synthesizing phase was marked by three consecutive signals, i.e., antigenic influence, interleukin-2, a specific T-lymphocyte cell growth factor, and non-specific serum growth-promoting factors, in the first place, transferrin. This system was used for the study of effects of virus SV40 T-antigen on cell mitotic cycle. Purified T-antigen was injected consecutively into T-lymphocytes, using erythrocyte ghost vesicles instead of one of control signals. It was shown that T-antigen cannot simulate the antigenic response but simulates the effect of interleukin-2, a specific growth-promoting factor. However, both normally proliferating T-lymphocytes and T-antigen-induced lymphocytes showed an absolute requirement for transferrin and, apparently, for other nonspecific growth-promoting factors. It was assumed that the polymorphism of tumours induced by papovaviruses is determined by the ability of their "early" proteins to imitate the effects of their specific growth-promoting factors on the cells.

[Induction of chromosome aberrations by the T antigen of the SV40 virus introduced into the cells using liposomes]. / Induktsiia khromosomnykh aberratsii T-antigenom virusa SV40, vvedennogo v kletki pri pomoshchi liposom.

A purified SV40 T antigen introduced into hamster cells by means of liposomes accumulated in the nuclei within 10 h and persisted there further as long as 10 to 12 h. Within the first day after cell treatment with T antigen numerous chromosome aberrations including breaks, translocations and gaps were observed in the cells. The number of aberrations slightly reduced by the 2nd day followed by restoration of the normal cell karyotype by the 5th day. Removal of T antigen incorporated into liposomes by a specific immunosorbent or heat inactivation of T antigen abolished the clastogenic effect. It is suggested that induction of chromosome aberrations might activate sell protooncogenes and thus serve a genetic basis of tumor progression.

[Possible role of the T antigen in inducing chromosome aberrations in SV40 virus-transformed cells]. / Vozmozhnaia rol' T-antigena v induktsii khromosomnykh aberratsii v kletkakh, transformirovannykh virusom SV40.

A possible role of the simian virus 40 T antigen in chromosome damages in transformed cells was examined. Two lines of Golden hamster embryonal fibroblasts, transformed by SV40 tsA30 and ts239 mutants (He30 and He239, respectively), were incubated at nonpermissive (40.5-41 degrees C) or permissive (33 degrees C) temperatures. Chromosome aberrations were registered in either subline after 3, 6, 9 and 12 weeks of cultivation under the above conditions. In the both cell lines kept at 33 degrees the frequency of aberrant metaphases and the number of chromosome breaks per cell increased drastically by week 3 of cultivation, and such a state was preserved up to week 12. The frequency of aberrant metaphases in cells cultivated at 41 degrees was maintained at the constant level (He239) or at slightly higher than that in the original culture (He30). The sublines He239, originally incubated at 33 or 40.5 degrees, were then shifted to 40.5 and 33 degrees, respectively. As a result the number of chromosome aberrations either decreased (33----40.5 degrees) or increased (40.5----33 degrees) as early as on day 2, and these patterns were stabilized at the level corresponding to the new conditions. We assayed the induction of DNA breaks in cells, grown at the permissive or nonpermissive temperatures, by using DNA sedimentation in the alkaline sucrose gradient. The DNA sedimentation peaks of cells cultured at 37 and 41 degrees coincided, whereas the DNA of cells cultured at 33 degrees was represented by shorter fragments.

[Induction of the replicative synthesis of DNA by SV40 virus T antigen introduced into cells using liposomes]. / Induktsiia replikativnogo sinteza DNK T-antigenom virusa SV40, vvedennogo v kletki s pomoshch'iu liposom.

The role of virus SV40 T-antigen in the induction of cell DNA synthesis during its incorporation into cell liposomes was studied, using monolamellar liposomes obtained by phase reversal with incorporated highly purified T-antigen. Immunofluorescence studies revealed that T-antigen effectively penetrates inside the cells and after 10 hours is accumulated in the nuclei, where its level remains unchanged for 24 hours. Injections of purified T-antigen into the renal cells of serum-starved CV1 monkeys resulted in an almost 10-fold increase in the number of DNA-synthesizing cells 18 hours after the exposure. The same effect was observed during stimulation of a 10% serum culture. Removal of T-antigen from the preparation by specific immunoadsorption eliminated this effect. Centrifugation of cells grown in the presence of bromodeoxyuridine in a CsCl gradient was used to demonstrate the replicative type of cell DNA synthesis during T-antigen induction.