Clastogenic effects of the fasciolicide drug fasinex on river buffalo lymphocyte cultures in vitro

Fasinex (triclabendazole) has been reported to be an active fasciolocidal agent used in humans and in farm animals. The clastogenic effects of fasinex were tested in lymphocyte cultures of the river buffalo at three final concentrations: 25, 50 and 100 microg/ml. Chromosomal aberrations, sister chromatid exchanges and micronucleus formation are the three cytogenetic parameters used in this study.The results demonstrated that the number of cells with different types of chromosomal aberrations, including chromatid breaks and gaps, isochromatid breaks and gaps and polyploidy, was increased significantly in cultures treated with different doses of fasinex compared to the control. This increase was dose-dependent where there was a positive correlation between increased drug concentration and induction of chromosomal aberrations.The frequency of sister chromatid exchanges and the formation of micronuclei in all lymphocyte cultures treated with different doses of fasinex were increased significantly compared to the control; these increases were also dose-dependent.In conclusion, the three cytogenetic parameters used to evaluate the effect of fasinex revealed that the drug has a strong clastogenic effect on river buffalo lymphocytes in vitro.     

Induction of chromosomal aberrations and sister chromatid exchanges by chlormadinone acetate in human lymphocytes: a possible role of reactive oxygen species

Genotoxicity study of a synthetic progestin chlormadinone acetate (CMA) was carried out in human lymphocytes using chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) as parameter. Effect of CMA was studied at 10, 20, 30 and 40 microM. CMA was genotoxic at 30 and 40 microM. With a view to study the possible mechanism of genotoxicity of CMA, superoxide dismutase (SOD) and catalase (CAT) were used separately and in combination along with the CMA (40 microM) at different doses. SOD treatment increased CAs and SCEs at both the doses. CAT treatment decreased the frequencies of CAs and SCEs in both, separately and in combination with SOD, suggesting a possible role of reactive oxygen species for the genotoxic damage.     

Anti-genotoxic effect of Ocimum sanctum L. extract against cyproterone acetate induced genotoxic damage in cultured mammalian cells

The anti-genotoxic effect of Ocimum sanctum L. extract was studied against the genotoxic effect induced by a synthetic progestin cyproterone acetate, on human lymphocytes using chromosomal aberrations, mitotic index, sister chromatid exchanges and replication index as a parameters. About 30 microM of cyproterone acetate was treated with O. sanctum L. infusion, at dosages of 1.075 x 10(-4), 2.125 x 10(-4) and 3.15 x 10(-4) g/ml of culture medium. A clear dose-dependent decrease in the genotoxic damage of cyproterone acetate was observed, suggesting a possible modulating role of the plant infusion. The results of the present study suggest that the plant infusion per se does not have genotoxic potential, but can modulate the genotoxicity of cyproterone acetate on human lymphocytes in vitro.     

Proliferative kinetics and mitomycin C-induced chromosome damage in Fanconi's anemia lymphocytes

Lymphocytes from two sisters with Fanconi's anemia (FA) were studied for cell cycle kinetics, sister chromatid exchanges (SCEs), and chromosomal aberrations when they had undergone one, two, or three or more divisions in mitomycin C (MMC)-treated cultures. Lymphocytes from the parents, another sister of the probands, and a healthy unrelated adult were examined as controls. Analyses of cell cycle kinetics by the sister chromatid differential staining method revealed that the relative frequency of metaphase cells at their third or subsequent divisions was much smaller in untreated FA cultures than in normal cultures fixed at 96 h after phytohemagglutinin stimulation. These data indicate that FA cells proliferate much more slowly than normal cells. MMC treatments of FA and normal cells led to a clearly dose-related delay in cell turnover times, the duration of delay being much longer in FA than in normal cells. FA cells had about 1.4 times higher frequencies of SCEs than normal cells in both MMC-treated and untreated cultures. FA cells also showed several times higher frequencies of chromosomal aberrations than normal cells, and the frequency of chromosomal aberrations decreased through subsequent mitoses by approximately 60% in both FA and normal cells.     

Protective role of allicin and L-ascorbic acid against the genotoxic damage induced by chlormadinone acetate in cultured human lymphocytes

In our present study, different doses of allicin and L-ascorbic acid were tested against the genotoxic damage induced by chlormadinone acetate (CMA; 40 microM) using chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) as the parameters. Treatment with allicin and L-ascorbic acid resulted in reduction of CAs and SCEs. The results suggested a protective role of allicin and L-ascorbic acid against CMA induced genotoxic damage.     

Genotoxic potential of medroxyprogesterone acetate in cultured human peripheral blood lymphocytes

Medroxyprogesterone acetate was studied at three different concentrations (1, 5 and 10 microM), for its genotoxic effects in human peripheral blood lymphocyte culture using chromosomal aberrations and sister chromatid exchanges as parameters. Duplicate peripheral blood cultures were treated with three different concentrations (1, 5 and 10 microM) of medroxyprogesterone acetate. The study was carried out both in the absence as well as in the presence of metabolic activation (S9 mix) with and without NADP. Medroxyprogesterone acetate was found genotoxic at 5 and 10 microM in the presence of S9 mix with NADP. To study the possible mechanism of the genotoxicity of medroxyprogesterone acetate, superoxide dismutase and catalase at different doses were used separately and in combination with 10 microM of medroxyprogesterone at different doses in the presence of S9 mix with NADP. Superoxide dismutase treatment results in an increase of the genotoxic damage but catalase treatment reduce the genotoxic damage of medroxyprogesterone acetate. Catalase treatment in combination with superoxide dismutase also results in the further reduction of the genotoxic damage. The results of the present study reveal that medroxyprogesterone acetate is genotoxic only in the presence of metabolic activation (S9 mix) with NADP. Treatments with superoxide dismutase and catalase suggests the possible generation of reactive oxygen species by redox cycling of various forms of quinones, similar to estrogens, that are the results of aromatic hydroxylation by cytochrome P450s.     

Sister chromatid exchange and chromosome aberrations induced by curcumin and tartrazine on mammalian cells in vivo

Sister chromatid exchanges (SCEs) and chromosomal aberrations induced by curcumin (a natural dye) and tartrazine (a synthetic dye) were studied on bone marrow cells of mice and rats following acute and chronic exposure via the diet. Except for two low concentrations in the curcumin and one low concentration in the tartrazine treated series a significant increase in SCEs was observed in all the concentrations of the two dyes tested. Except for two high concentrations during the 9 months treatment no significant increase in chromosomal aberrations was observed in the curcumin treated series, whereas tartrazine showed a significant increase in chromosomal aberrations in some of the higher concentrations in all the series tested. The results indicate that tartrazine is more clastogenic than curcumin.     

Studies on the genotoxic effects of aminophenazines using two cellular models and three different methods

This paper presents studies on the genotoxicity of two aminophenazines: 2,3-diaminophenazine (DAP) and 2-amino-3-hydroxyphenazine (AHP). The genotoxic activities of these compounds were evaluated with human lymphocytes using the alkaline single cell gel electrophoresis (SCGE) assay and two cytogenetic assays (chromosome aberrations (CA) and sister chromatid exchange (SCE) analysis). Results show that these chemicals elicited an increase in DNA and chromosomal damage under the studied ranges of concentration. Concentration-response curves were similar and there was a positive correlation between the damage observed at the DNA and chromosomal levels. DAP was more genotoxic than AHP and this agreed with the genotoxic potencies reported in bacterial systems.     

Cytogenetic effect of the anticancer drug epirubicin on Chinese hamster cell line in vitro

The present study demonstrated the cytogenetic effect of the anticancer drug epirubicin on cultures of Chinese hamster cell line in vitro. The cultures were exposed to the drug for 24 h at three final concentrations; 10, 20 and 40 microg/ml. All treatments were carried out in the absence of any exogenous metabolic activation system.The different types of structural chromosomal aberrations, including gaps, breaks, deletions and fragments were increased in epirubicin-treated cultures. This increase was dose dependent where there was a positive correlation between increased drug concentration and induction of structural chromosomal aberrations. Also, the numerical chromosomal aberrations, including hypodiploidy and hyperdiploidy, were increased significantly in epirubicin-treated cultures. Like structural aberrations, the increase of numerical chromosomal aberrations was also dose-dependent.The frequency of sister chromatid exchanges in cultures treated with epirubicin increased significantly and this increase was dose-dependent. On the other hand, the epirubicin significantly decreased the mitotic index in treated cultures of Chinese hamster cell line.     

IPCS guidelines for the monitoring of genotoxic effects of carcinogens in humans. International Programme on Chemical Safety

The purpose of these guidelines is to provide concise guidance on the planning, performing and interpretation of studies to monitor groups or individuals exposed to genotoxic agents. Most human carcinogens are genotoxic but not all genotoxic agents have been shown to be carcinogenic in humans. Although the main interest in these studies is due to the association of genotoxicity with carcinogenicity, there is also an inherent interest in monitoring human genotoxicity independently of cancer as an endpoint.The most often studied genotoxicity endpoints have been selected for inclusion in this document and they are structural and numerical chromosomal aberrations assessed using cytogenetic methods (classical chromosomal aberration analysis (CA), fluorescence in situ hybridisation (FISH), micronuclei (MN)); DNA damage (adducts, strand breaks, crosslinking, alkali-labile sites) assessed using bio-chemical/electrophoretic assays or sister chromatid exchanges (SCE); protein adducts; and hypoxanthine-guanine phosphoribosyltransferase (HPRT) mutations. The document does not consider germ cells or gene mutation assays other than HPRT or markers of oxidative stress, which have been applied on a more limited scale.     

Genotoxicity assessment in patients with thalassemia minor

Thalassemia is an inherited blood disorder that affects both genders and results in reduced synthesis of hemoglobin, and thus causing anemia. Previous studies have shown that the severe form of this disease, thalassemia major, is associated with genotoxicity. This includes increases in the level of sister chromatid exchange (SCEs), chromosomal aberrations (CAs) and micronuclei. In this study, we assessed genotoxicity in the lymphocytes of thalassemia minor subjects using sister chromatid exchange (SCE) and chromosomal aberration (CA) assays. In addition, we investigated the level of oxidative DNA damage by measuring 8-hydroxy-2'-deoxyguanosine (8OHdG) biomarker in urine samples. Eighteen thalassemia minor subjects and eighteen matched normal healthy controls were volunteered in the study. In addition, seven thalassemia major patients were recruited as positive controls. The results showed increases in the frequency of SCEs (P<0.05) in thalassemia minor compared to healthy controls. However, no difference in CAs frequency was detected between thalassemia minor and controls (P>0.05). Both SECs and CAs in thalassemia major patients were significantly higher compared to other groups (P<0.05). Regarding urine 8OHdG levels, the result showed a slight increase in thalassemia minor compared to healthy controls but the difference was not significant (P>0.05). In conclusion, our results showed that thalassemia minor is associated with genotoxicity to blood lymphocytes as indicated by SCEs assay.     

The cytogenetic evaluation of in vivo genotoxic and cytotoxic activity using rodent somatic cells

With the growing realization that in vitro short-term tests for genotoxicity can never fully mimic in vivo conditions, the evaluation of genotoxic damage in somatic cells of rodents has played an increasingly important role in assessing the carcinogenic potential of suspect compounds. Among the various genotoxic endpoints assessed in in vivo somatic cell assays, cytogenetic endpoints (e.g., chromosomal aberrations, micronuclei, sister chromatid exchanges) continue to be used most frequently. The purpose of this paper is to demonstrate the utility of evaluating different cytogenetic endpoints in the same animal, using as examples studies to evaluate the in vivo genotoxic potential of benzene, of methylisocyanate, and of butadiene, chloroprene and isoprene.Abbreviations CA chromosomal aberrations - MI mitotic index - MIC methylisocyanate - MN-NCE micronucleated monochromatic erythrocytes - MN-PCE micronucleated polychromatic erythrocytes - SCE sister chromatid exchange     

Genotoxic potential of ethinylestradiol in cultured mammalian cells

Ethinylestradiol, a steroidal estrogen, is widely used with various progestogens in oral contraceptives formulations. There are sufficient evidences for the carcinogenicity of ethinylestradiol in experimental animals. The reports on the genotoxic potential of ethinylestradiol are contradictory. Here in the present study we have tested the genotoxicity of ethinylestradiol in human lymphocytes using chromosomal aberrations (CAs), mitotic index (MI) and sister chromatid exchanges (SCEs) as a parameter. The study was carried out in the absence, as well as in the presence, of rat liver microsomal fraction, with and without NADP. Ethinylestradiol was studied at three different concentrations (1, 5 and 10 microM) and was found non-genotoxic in the absence of metabolic activation (S9 mix) and in S9 mix without NADP. Ethinylestradiol was found to be genotoxic at 5 and 10 microM in the presence of S9 mix with NADP. To study the possible mechanism of the genotoxicity of ethinylestradiol, superoxide dismutase (SOD) and catalase (CAT) were used separately and in combination along with 10 microM of ethinylestradiol at different doses. SOD treatment increased CAs and SCEs and decreases MI as compared with treatment with 10 microM of ethinylestradiol alone in the presence of S9 mix with NADP at both of the tested doses. CAT treatment decreased the frequencies of CAs and SCEs and increased MI, as compared with treatment with 10 microM of ethinylestradiol alone in the presence of S9 mix with NADP. CAT treatment in combination with SOD also decreased the frequencies of CAs and SCEs and increased MI suggesting a possible role of reactive oxygen species for the genotoxic damage.     

脉冲电磁场对家猪淋巴细胞的细胞遗传学效应

以家猪外周血淋巴细胞为材料,研究了脉冲电磁场（pulsing electromagnetic fields,简称PEMFS)树细胞的遗传学效应,实验发现,100和200kHz的PEMFs对家猪的淋巴细胞照射培养12,24,48h后,染色体畸变（包括非整倍体,染色体断裂等）频率明显高于对照组（P＜0．05）,其中,56％的染色体或染色单体断裂和42％的间隙发生在家猪常见染色体脆性位点部位,同时, 经100kHz和200kHz的PEMFs照射48h后,淋巴细胞姐妹染色单体交换（SCE）频率也明显高于对照组（P＜0．05）,实验结果表明,PEMFS能诱导DNA损伤和染色体畸变。     

Cytogenetic study of the effect of <Emphasis Type="Italic">Schistosoma mansoni</Emphasis> infection on human peripheral blood lymphocytes and the role of β-carotene and vitamin E in modulating this effect

This study has been made to determine the potential genotoxicity of Schistosoma mansoni on lymphocytes of infected patients using different mutagenic end points. The protective role of antioxidants pro vitamin β-carotene and vitamin E in minimizing these genotoxic effect was also studied. The study focused on the effect of schistosomiasis on the induction of sister chromatid exchange (SCEs) and other chromosomal aberrations. This work was conducted on 24 Schistosoma mansoni infected patients and 10 healthy adults as a control group. Lymphocytes from peripheral blood of patients and control group were used for culture and subsequent cytogenetic studies. The results indicated that schistosomiasis was genotoxic in all examined tests. It induced a significant increase in the percentage of structural chromosomal aberrations and the frequency of SCEs. It also inhibited cell division and caused cell cycle delay. Lymphocyte cultures of S. mansoni patients treated with 10 μg/ml β-carotene or 20 mg/ml vitamin E showed a significant decrease in the percentage of structural chromosomal aberrations and the frequency of SCEs. Schistosomiasis has a genotoxic effect on peripheral blood lymphocytes. The use of the antioxidants β-carotene and vitamin E can be considered a promising approach not only toward inhibiting the genetic damage of schistosomiasis but also as prophylactic agents against infection with S mansoni. Furthermore, higher doses of antioxidant drugs, β-carotene and vitamin E, should be tried as an adjuvants to conventional therapy in a trial to improve treatment of schistosomiasis.     

Sister chromatid exchanges in Vicia faba

The relationship between chromosomal aberrations and sister chromatid exchanges (SCE's) after treatment of Vicia faba root tips with thiotepa, caffeine and 8-ethoxycaffeine (EOC) was studied by using a modified fluorescent plus Giemsa (EPG) technique. At concentrations which had little effect on the frequency of chromosomal aberrations, thiotepa strongly increased the frequency of SCE's, provided that the chromosomes were allowed to replicate between treatment and fixation. Frequently, the size of the exchanged material was smaller than the diameter of the chromatid. Post-treatments with caffeine of roots previously exposed to thiotepa strongly increased the frequency of aberrations, but had little effect on the frequency of SCE's. In contrast to thiotepa, EOC caused only a slight increase in the frequency of SCE's even at concentrations which produced a high frequency of chromosomal aberrations. Thus, there was not a close correlation between SCE's and chromosomal aberrations. Single-strand exchanges between the DNA double helices in sister chromatids were not detected.     

The biological activity of hydrogen peroxide. IV. Enhancement of its clastogenic actions by coadministration of L-histidine

An enhancing effect of L-histidine (L-His) was detected on the induction by hydrogen peroxide (H2O2) of chromosomal aberrations of both the chromosome type and the chromatid type, in human embryonic fibroblasts. The maximum efficiency of induction was about 8-fold higher in the presence of L-His than in the presence of H2O2 alone, at a concentration of L-His of 50 microM. D-His and DL-His showed lower enhancing effects than L-His, with approximately 2-fold and 5-fold enhancement of induction of chromosomal aberrations, respectively. L-Histidinol and L-His-methyl ester, among various derivatives of L-His tested, also enhanced this process. However, the effects of these derivatives were smaller than those of L-His in a range of concentrations equivalent to that of the most effective dose of L-His (50 microM), while they produced greater enhancement than L-His at concentrations higher than 200 microM. Other derivatives of L-His, such as L-carnosine, urocanic acid, imidazolepyruvic acid, 1-methyl-L-His, imidazolelactic acid, imidazoleacetic acid and histamine and imidazole itself did not enhance the frequency of chromosomal aberrations induced by H2O2. These results indicate that at least both the imidazole ring and the amino group are essential components of the chemical structure of L-His required for the enhancing effect. Moreover, in order to cause such an enhancing effect, L-His had to be applied together with H2O2 to cells, because the enhancing effect of L-His was not observed with cells which were washed after pretreatment with L-His. The preliminary study suggested that this enhancing effect depends on the His-peroxide adduct derived from L-His and H2O2. None of the amino acids tested other than His produced any enhancing effect on the induction of chromosomal aberrations by H2O2.     

Genotoxic effect of benzene hexachloride in cultured human lymphocytes

Summary Chromosomal aberrations, sister chromatid exchanges, mitotic index and cell kinetics were observed in human peripheral lymphocytes after treatment with four different concentrations (0.0125, 0.025, 0.05 and 0.1 g/ml) of benzene hexachloride (BHC), an organochlorine pesticide. Cells were treated with BHC for 24, 48 and 72h. There was a dose-dependent increase in the frequency of chromosomal aberrations and sister chromatid exchanges. A significant decrease in mitotic index was observed at all concentrations and times of exposure. BHC did not show a significant effect on cell kinetics.     

Vicia faba chromosome damage induced by low doses of gamma radiation

The rate of radiation damage to chromosomes by low doses of gamma rays (0.01-0.30 Gy) was studied in the root tips ofVicia faba. As criteria of the effect of ionizing radiation, the frequency of sister chromatid exchanges (SCEs), incidence of chromosomal aberrations and the number of micronuclei were evaluated and compared in irradiated cells. The results obtained confirmed that the analysis of SCEs did not represent an efficient indicator of radiation damage to chromosomes. On the contrary, the formation of chromosomal aberrations and micronuclei was effectively stimulated by low radiation doses, there being linear dose-effect relationships in the low doses region used.     

The effect of sera on sister chromatid exchanges in vitro

To study viral effects on sister chromatid exchange (SCE), human diploid fibroblasts were infected with herpes simplex virus (HSV) of type-1 and type-2. Both types of virus produced remarkable chromosomal aberrations in the early phases of the infection, but neither of them caused an increase in the SCE frequency over the uninfected control level. Analysis of the breakpoints of chromatid deletions with respect to their association with SCE revealed that the chromatid deletions induced by HSV arose independently of the sites of SCE. It is probable that the genesis of virus-induced chromosomal aberrations is unrelated to the molecular processes that function in SCE formation.