Tofisopam--evaluation of mutagenic and genotoxic properties.

The mutagenic properties of tofisopam, the member of the 2,3-benzodiazepine family, were evaluated on the basis of Ames test with Salmonella typhimurium TA1537, TA97, TA98, TA100 and TA102 strains. The genotoxic properties of tofisopam were estimated on L929 cell line with the cytokinesis-block technique. Under the experimental conditions, no mutagenic activity of tofisopam in tester bacteria strains was found, and no genotoxic activity was observed.

Influence of metabolic activation on the induction of micronuclei by antihypertensive drugs in L929 cells.

The influence of metabolic activation on the genotoxic activity of the antihypertensive drugs hydralazine and dihydralazine was investigated. An in vitro micronucleus test for estimating the genotoxic activity of these drugs was used. The results obtained indicated that hydralazine and dihydralazine induce micronuclei formation in L929 cells. When L929 cell cultures were treated with drugs together with liver membrane fraction (S9 fraction) from polychlorinated biphenyl (Aroclor 1254) induced rat liver, the number of micronucleated cells decrease, however, almost to the level found in control cultures. The experiments with modified S9 mix allow the conclusion that the antioxidant enzymes catalase and superoxide dismutase present in S9 liver fraction play a role in the protection of cells from the genotoxic action of hydralazine and dihydralazine.

The study on adriamycin induced DNA scissions in human cells with different activity of some antioxidant enzymes.

Although the anthracycline antibiotic adriamycin has been widely used in treatment of variety of human malignances, the mechanism of its biological activity is still unknown. One of the proposed mechanisms of action assumes the generation of active oxygen species which may damage DNA of cells. In this study we investigated if the occurrence of DNA breaks induced by adriamycin depends on the intracellular level of antioxidant enzymes. The study was performed with two human cell lines (CRL2088 and CLV102) differing in activity of catalase and superoxide dismutase. The results indicated that the level of DNA breaks in both lines treated with adriamycin was similar despite of differences in the enzymes activity.

Studies on the mutagenic activity of hydralazine and dihydralazine in Salmonella typhimurium strains differing in expression of antioxidant genes.

The mutagenic activity of two antihypertensive drugs, hydralazine and dihydralazine was investigated in oxyR- proficient (TA104) and -deficient (TA4125) Salmonella typhimurium strains showing different ability to induce proteins involved in protection of the cells against oxidative damage. The results of the Ames test demonstrated that dihydralazine, in contrast to hydralazine, was mutagenic for oxyR- strain at concentrations that were nonmutagenic for oxyR+ strain. The scavenger of superoxide anion, superoxide dismutase decreased in both strains the number of revertants induced by dihydralazine but not by hydralazine. The results may suggest that active oxygen species generated by dihydralazine contribute to its mutagenicity.

Genotoxicity of adriamycin in human cell lines differing in antioxidant enzymes activity.

Genotoxicity of adriamycin in human cell lines was investigated by using a micronucleus assay. The result obtained was negative: the cells treated showed no increase in micronuclei. The chromosome aberration study with adriamycin indicated that the number of aberrant cells, high immediately after treatment, decreased to nearly the control level in 24 h of postincubation, probably as a result of the DNA repair process. Experiments with caffeine--a DNA repair inhibitor--indicated an increase micronuclei in the cells treated with adriamycin and caffeine together. The results obtained suggest that, in a human cells, adriamycin--induced DNA damages are quickly repaired to prevent micronuclei formation.

The in vitro study on genotoxic activity of adriamycin and bleomycin in cells of mice with different catalase and superoxide dismutase activity.

Genotoxic activity of adriamycin and bleomycin in embryo cells from mice differing in anti-oxidant enzymes activity was investigated. The catalase activity in cultured in vitro embryo cells of C3H mice was 2.3-fold and superoxide dismutase 2.5-fold higher than of C57BL/10 mice. For genotoxicity evaluation, the micronucleus test in vitro was used. The results obtained indicated that the frequency of micronucleated cells in untreated C3H cultures was higher than in C57BL/10 cell cultures. The increase in micronuclei formation after treatment with adriamycin and bleomycin was higher in C57BL/10 than in C3H cells as compared with micronuclei in untreated cultures. The higher frequency of micronucleated cells in treated versus untreated C57BL/10 than C3H cell cultures may be caused by lower activity of anti-oxidant enzymes in C57BL/10 cells. It may suggest that DNA damage caused by adriamycin and bleomycin resulted from action of active oxygen species.

Characteristics of mutagenesis by bleomycin and adriamycin in Salmonella typhimurium: action of catalase.

The influence of catalase activity in adriamycin and bleomycin mutagenesis was investigated in Salmonella typhimurium TA98 and TA102, respectively. The activity of catalase in bacterial cells was inhibited by sodium azide. Mutagenicity of both drugs was not changed in bacterial cells with depressed catalase activity.

Genotoxicity of hydrazino-phtalazine antihypertensive drugs assessed by an in vitro micronucleus assay.

The genotoxicity of antihypertensive drugs, hydralazine, dihydralazine and binazine was assessed on the base of their capacity to induce micronuclei in L929 cell line. In our previous investigations we indicated that these drugs did not induce micronuclei in bone marrow polichromatic erythrocytes in PZH SFISS mice. Present results show that hydralazine and dihydralizine can induce micronuclei in vitro and that this effect depends on time of exposure and the concentration of drug.

Characteristics of mutagenesis by bleomycin and adriamycin in salmonella typhimurium: action of superoxide dismutase.

The role of reactive oxygen species in adriamycin and bleomycin-induced mutagenicity was investigated in Salmonella typhimurium TA98 and TA102 respectively. Activity of superoxide dismutase (SOD) was inhibited by preincubation of bacteria with diethyldithiocarbamate (DEDTC). Results of Ames test may suggest the involvement of active oxygen species in bleomycin induced mutagenesis and an absence of their participation in adriamycin induced mutagenesis.

Genetic effects of binazine and hydralazine in vitro and in vivo.

The mutagenic and genotoxic activities of binazine and hydralazine were studied. In the Ames test, both with and without S-9 fraction, hydralazine was mutagenic in strains Salmonella typhimurium TA100 and TA1537, whereas binazine was not mutagenic in these strains. Both drugs were negative in mice micronucleus test.

Studies on the mechanism of mutagenicity and genotoxicity induced by dihydralazine.

Dihydralazine was found to be mutagenic towards S. typhimurium TA1537, TA97, TA1538 and TA98 and genotoxic towards E. coli PQ37. Using the nitro blue tetrazolium reduction method we have found that dihydralazine can generate active oxygen species. The possible role of active oxygen species in mutagenicity (Ames test) and genotoxicity (SOS Chromotest) of dihydralazine was studied by testing the influence of the different active oxygen species scavengers on these two processes. Of the active oxygen scavengers tested, only superoxide dismutase suppressed partially the mutagenic and genotoxic activity of dihydralazine. This result seems to indicate that superoxide anion play a role in these two biological events.

Evaluation of mutagenic and genotoxic properties of TPP.

For evaluation of mutagenic and genotoxic properties of Tolpa Peat Preparation (TPP) four selected short-term tests were employed. TPP has been found to be neither mutagenic nor genotoxic.

Evaluation of the SOS chromotest for detection of genotoxic drugs.

In the present investigation, the SOS Chromotest with E. coli PQ37 was evaluated. The potential of the test to identify genotoxic properties of different cytostatics was examined. Only intercalating agents showed good activity. The SOS Chromotest appeared to be less effective than the Salmonella mutagenicity test in the detection of alkylating agents.

Evaluation of mutagenic, genotoxic and transforming properties of Ukrain.

Evaluation of mutagenic and genotoxic properties of Ukrain was on the basis of the Ames and micronucleus tests. Ukrain was investigated for its ability to induce morphological transformation of embryonic cells of the Syrian hamster. Under the experimental condition used in this study, Ukrain was found to be non-mutagenic and non-genotoxic, and furthermore did not induce morphological cell transformation.

An evaluation of antimutagenic properties of vitamin E.

The influence of vitamin E on the mutagenic activities of aflatoxin and adriamycin was studied. The results indicate that vitamin E shows antimutagenic activity towards aflatoxin B1 only when homogenized with liver tissue.

Effects of riboflavin on benzo(a)pyrene, 2-acetylaminofluorene and methyl methanesulfonate mutagenicity in vitro.

Riboflavin was shown to inhibit mutagenicity of benzo(a)pyrene and 2-acetylaminofluorene in the presence of S9 liver fractions deriving from B10.A mice as well as from DBA/2 mice and had no influence on mutagenicity of methyl methanesulfonate. The above findings confirm the supposition that antimutagenicity of riboflavin results from its interaction with enzymes responsible for metabolic activation of promutagens. The antimutagenic effects of riboflavin were more drastic in the presence of liver fractions from B10.A mice than in the presence of those from DBA/2 mice.

Comparison of transforming, antimitotic and chromosomal aberration-inducing properties of melphalan and cyclophosphamide.

Melphalan and cyclophosphamide, cytostatics used for cancer therapy, were investigated for their ability to induce morphological transformation of embryonic cells of the golden hamster and to evoke structural chromosome aberrations. The antimitotic action of both drugs was also investigated. Cyclophosphamide, under conditions in which it did not produce either structural chromosomal aberrations or exerted cytotoxic action, induced morphological transformation of hamster cells. Under the experimental conditions melphalan induced morphological transformation of hamster cells at concentrations not inducing chromosomal aberrations.

Transforming activities of methotrexate, hydroxyurea and 5-fluorouracil in different cell systems.

The transforming ability of methotrexate, hydroxyurea and 5-fluorouracil was studied in mass cultures of embryo cells from BN/a, DBA/2 and Swiss mice. As estimated by virological methods the cells from BN/a mice were infected persistently with ectromelia virus. In parallel a quantitative transformation assay with a cloned BALB/3T3 cell line was employed. Oncogenic transformation could be induced repeatedly in mass cultures from BN/a mice after treatment with every of chemotherapeutic agents studied. Neither of the drugs induced transformation in the cultures deriving from two other strains of mice. In the cloned BALB/3T3 cell line from the three drugs tested only methotrexate induced the appearance of transformed foci, however, the yield of transformants was very low. It has been concluded that under the employed experimental conditions the transforming ability of hydroxyurea and 5-fluorouracil could be expressed exclusively in the cells infected with ectromelia virus. The transforming ability of methotrexate seems to depend either on the presence of viral infection or on the properties of cells enabling additional events necessary for transformation.

[Effect of lack of exogenous methionine on protein synthesis in normal and leukemic leukocytes cultured in vitro]. / Wplyw braku metioniny egzogennej na synteze bialka w prawidlowych i bialaczkowych krwinkach bialych w hodowli in vitro.

Experiments were performed on lymphocytes and leucocytes isolated from peripheral blood of healthy donors and on leucocytes from patients with acute myeloblastic and acute lymphoblastic leukaemia. The influence on protein synthesis of methionine depletion in the medium or replacement of methionine by homocysteine was measured in labelling experiments with tritiated valine. The rate of protein synthesis in lymphocytes and leucocytes from healthy donors cultivated in homocysteine--containing medium and stimulated with PHA did not differ significantly in the course of 5 days from the rate of protein synthesis in the basic medium. In leukaemic leucocytes cultivated in vitro in the time period of 34 h in the rate of protein synthesis in homocysteine--containing medium was similar to the rate of protein synthesis in the medium devoid of methionine.