Induction of precise excision of transposons Tn1 and Tn10 from the genes met::Tn1 and cys::Tn10 by chemical agents, having mutagenic and DNA damaging activities, has been studied. The drugs dioxydin, NMU, photrin, phopurine, thiophosphamid, rongeron as well as sodium azide, 2-NP, DDDTDP are shown to differ in their ability to stimulate the precise excision of transposons of different classes and in the efficiency of stimulated process. Results of the present paper are in proof of the possible using of experimental model, based on registering the precise excision of transposons, for screening the mutagenic and cancerogenic activities of chemical agents from the environment.

The effect of blastolysin, a glycopeptide of the cell walls of L. bulgaricus, on the resistance of mice to infections caused by S. typhimurium and B. pertussis, lysozyme levels in the blood serum and 5'-nucleotidase activity of peritoneal macrophages was studied. The changes in the nonspecific resistance of mice due to the effect of blastolysin depended on the administration route and the type of the developing infection. It activated the enzymatic activity of the peritoneal macrophages and changed the lysozyme levels in the blood serum of mice. The optimal protective effect of blastolysin was achieved on intramuscular injection in a dose of 100 micrograms.

It is shown that under the influence of phosphemide in combination with dexamethasone some characteristics of tumour DNA (content of 5 methyl cytosine, temperature, interval and enthalpy of melting) approximate the corresponding characteristics of DNA of healthy animals' liver better than under the influence of phosphemide only.

The level of chromosome aberrations induced by mitomycin C and cytosine arabinoside in the cultured lymphocytes from patients with chronic alcoholism is elevated, as compared to that observed in the cultured lymphocytes of healthy persons. A supposition was made that transitory instability of cell genome could cause this phenomenon.

Morphology and functional activity of peritoneal macrophages were studied at different intervals after the administration of blastolysin to Wistar rats. Alteration of the macrophage ultrastructure and their functional activity proving the stimulatory effect of the preparation on cells is shown. The signs of stimulation were revealed 30 minutes after the administration of the drug, reached a maximum on the 7th and 14th days and was manifested by structural changes of the cell surface, lysosomal apparatus, mitochondria and by activation of phagocytosis.

The report deals with damaging effects on the structure of a supramolecular DNA complex of leukemic cells in P388 mice, susceptible to most antitumor preparations, following treatment with therapeutic doses of sarcolysin, methylnitrosourea, actinomycin D and adriamycin. Capillary elastoviscosimetry and nucleoid sedimentation procedure showed that damage to supramolecular DNA complex structure became apparent as quickly as 15-60 min after injection of the said preparations and persisted for several days. The said damage consisted in DNA's filaments rupture and alterations in higher-order chromatin structures. The role of conformational changes of supramolecular DNA complex in the course of the cytotoxic action of antitumor agents is discussed.

The carminomycin-resistant strain (P-388/c) of P-388 lymphoid leukemia is obtained. Resistance development is accompanied by higher sensitivity to cytostatics, rise of hyperploidy, replacement of the stem line, presence of definite markers in leukemic cells as well as by the appearance of a clone of cells with higher dry mass. At the level of CFUs after the carminomycin administration more remote terms of cell restoration than in case of P-388/c lymphoid leukemia are determined. The P-388/c lymphoid leukemia cells lost their sensitivity to carminomycin at the stage of the DNA synthesis. Accumulation of cells is observed in phase G2 of the mitotic cycle.

The work deals with analysis and planning of experiments in one of the testing methods for potential genetic activity of chemicals--in the test for sperm abnormality in mice. A novel way of analysis of experimental data using consecutive scheme of microscopy of preparations has been suggested which came to be more convenient and economically advantageous in routine work.

There was no direct inhibition of DNA synthesis in ascites hepatoma 22A cells after intraperitoneal injection of single doses of copper (II) complexes with amino acids into tumor-bearing C3HA mice. Meanwhile cis-dichlorodiamine platinum (II) (DDP) as well as sarcolysine showed such inhibition. Copper (II) complexes with alpha-amino acids displayed as significant superoxide dismutase-like activity at concentrations corresponding to therapeutic doses of these compounds. The complexes of copper (II) combined with DDP give an additive antitumor effect in solid tumors of mice.

The effect of unitiol treatment on the toxicity of dactinomycin, 5-fluorouracil, bleomycetin and vincristine was studied in CBA mice. Unitiol treatment was shown to decrease the acute toxicity of dactinomycin and involves a lower loss of body weight. Also, it reduced dactinomycin hemotoxicity which was assessed on the basis of leukocyte count in peripheral blood. Conversely, unitiol potentiated the acute toxic effect of 5-fluorouracil, bleomycetin and vincristine which was matched by body weight loss following treatment with cytostatic drugs. The results point to a wide range of the biological effects of unitiol.

The paper discusses the biological properties of 2-(2-furyl)-5-oxymethyl-5-(2,4-diethyleneimino-1,3,5-triazine- 6-yl) amino-1,3-dioxane (furizil), synthesized by substituting ethyleneimine groups for chlorine atoms in individual stereoisomer of a dichlorotriazine derivative. Furizil was found to inhibit the growth of Ehrlich's tumor, Walker's carcinosarcoma, sarcoma 45 and rat ovarian tumors, the inhibition rate ranging 76-100%. Parenterally administered, LD50 appeared to be 6 mg/kg for rats and 15 mg/kg for mice. Studies of chronic toxicity established damaging effects of furizil on hematopoietic, gastrointestinal and reproductive organs. Toxic effects subsided 1-2 weeks after the drug withdrawal.

The immunosuppressant effects of the antineoplastic piperazine drugs spirobramine and prospidin in respective doses of 500 and 600 mg/kg (1/2 of the LD50) were studied in experiments on cats. Spirobramine was shown to exert a more pronounced immunoinhibitory action on the primary and secondary immune response induced by sheep red blood cells.

The optical properties of the DNA complexes with the compounds of bivalent platinum were studied. The compounds differed by the nature of the anionic and neutral ligands and their spatial arrangement about the platinum atom. It was shown that the same as cis-[Pt (NH3)2Cl2] the platinum compounds with the biological activity, i.e. [Pt (en) Cl2], cis-[PtNH3 (Bz) Cl2] and cis-[Pt (NH3)2NO2Cl] induced at low values of r (a ratio of the number of the platinum moles added to the number of the DNA nucleotide moles in the solution) an increase in the amplitude of the positive band in the spectrum of the circular dichroism (CD) of the linear DNA and a marked decrease in the amplitude of the negative band in the spectrum of the CD of the liquid crystalline microphase of DNA formed in the presence of polyethyleneglycol. By the character of the action on the CD spectrum of the linear and condensed DNA [Pt (tetrameen)Cl2] which had no selective antimitotic effect might be referred to the above platinum compounds. Trans-[Pt (NH3)2NO2Cl], [PtNH3PyCl2], cis-[Pt (NH3)2(NO2)2] and [Pt (NH3)3Cl]Cl having no biological activity either induced only a decrease in the amplitude of the positive band in the CD spectrum of the linear DNA or had no effect on the CD spectrum. The effect of these compounds on the CD spectrum of the liquid crystalline microphase of DNA was slightly pronounced or not observed.

A single administration of the LD50 of bruneomycin, carminomycin, rubomycin or olivomycin and the use of the antibiotics for 10 days in a dose 2 times higher than the therapeutic one and amounting to 10 per cent of the LD50 induced dystrophic and destructive changes in the sexual glands of mice. The changes in the testis were more pronounced after the single use of the antibiotics. Recovery processes were observed in the testis beginning from the middle of the third week after the use of carminomycin and rubomycin and from the end of the second week after the use of olivomycin. Bruneomycin was an exception: the pronounced destructive changes in the sexual glands after its single or repeated use persisted within the observation period.

Alterations in DNA synthesis induced by 1,2:5,6-dianhydrogalactitol (DAG) and 1,2:5,6-dianhydro-3,4-diacetyldianhydrocalactitol (Diac-DAG) were studied in host normal cells and tumor cells. After administration of these antitumor drugs to melanoma B16-bearing mice, DNA synthesis in host tissues (bone marrow, gastrointestinal mucosa, spleen, liver) got recovered more rapidly than DNA synthesis in melanoma B16. Diac-DAG differed from DAG from the standpoint of damage to DNA synthesis in normal cells. Only DAG inhibited the DNA synthesis in liver cells. Inhibition of DNA synthesis in the bone marrow and spleen with Diac-DAG was less remarkable than with DAG.

The effect of reumycin, an antitumor antibiotic on the peripheral circulatory system and bone marrow was studied on albino rats. The drug was injected intraperitoneally in a dose of 25 mg/kg daily for 30 days. It was shown that reumycin had a comparatively low toxic effect on the peripheral circulatory system and hemopoiesis. It induced the signs of transitory anemia and did not suppress the regenerative capacity of the bone marrow. After the drug repeated use there was an increase in the platelet count and in the rate of blood coagulation. These signs vanished a month after the end of the treatment course.

Antiproliferative activity of 5'-deoxy-5'-S-isobutylthioadenosine (SIBA) was studied in mouse tumor and medullary cells in vitro and in vivo. Essential differences were found in the antiproliferative action of SIBA on medullary and tumor cells in vivo and in vitro. It was shown that in vitro SIBA drastically inhibited DNA synthesis (by more than 80-90%) in all cells under test, whereas in vivo it stimulated 3H-thymidine incorporation into DNA of the ascites tumor cells and medullary cells of mice with lymphoma NK/Ly.