Chromosome aberration and micronucleus frequencies in Allium cepa cells exposed to petroleum polluted water - A case study

In the present study, we applied Chromosome Aberration (CA) and Micronucleus (MN) tests to Allium cepa root cells, in order to evaluate the water quality of Guaeca river. This river, located in the city of Sao Sebastiao, SP, Brazil, had been affected by an oil pipeline leak. Chemical analyses of Total Petroleum Hydrocarbons (TPHs) and Polycyclic Aromatic Hydrocarbons (PAHs) were also carried out in water samples, collected in July 2005 (dry season) and February 2006 (rainy season) in 4 different river sites. The largest CA and MN incidence in the meristematic cells of A. cepa was observed after exposure to water sample collected during the dry season, at the spring of the river, where the oil leak has arisen. The F, cells from roots exposed to such sample (non-merismatic region) were also analyzed for the incidence of MN, showing a larger frequency of irregularities, indicating a possible development of CA into MN. Lastly, our study reveals a direct correlation between water chemical analyses (contamination by TPHs and PAHs) and both genotoxic and mutagenic effects observed in exposed A. cepa cells. (C) 2007 Elsevier B.V. All rights reserved.

The HUman MicroNucleus project on eXfoLiated buccal cells (HUMNXL): The role of life-style, host factors, occupational exposures, health status, and assay protocol

The human buccal micronucleus cytome assay (BMCyt) is one of the most widely used techniques to measure genetic damage in human population studies. Reducing protocol variability, assessing the role of confounders, and estimating a range of reference values are research priorities that will be addressed by the HUMNXL, collaborative study. The HUMNXL, project evaluates the impact of host factors, occupation, life-style, disease status, and protocol features on the occurrence of MN in exfoliated buccal cells. In addition, the study will provide a range of reference values for all cytome endpoints. A database of 5424 subjects with buccal MN values obtained from 30 laboratories worldwide was compiled and analyzed to investigate the influence of several conditions affecting MN frequency. Random effects models were mostly used to investigate MN predictors. The estimated spontaneous MN frequency was 0.74 parts per thousand (95% CI 0.52-1.05). Only staining among technical features influenced MN frequency, with an abnormal increase for non-DNA-specific stains. No effect of gender was evident, while the trend for age was highly significant (p < 0.001). Most occupational exposures and a diagnosis of cancer significantly increased MN and other endpoints frequencies. MN frequency increased in heavy smoking (>= 40 cig/day. FR = 1.37:95% CI 1.03-.82) and decreased with daily fruit consumption (FR = 0.68; 95% CI 0.50-0.91). The results of the HUMNXL, project identified priorities for validation studies, increased the basic knowledge of the assay, and contributed to the creation of a laboratory network which in perspective may allow the evaluation of disease risk associated with MN frequency. (C) 2011 Elsevier B.V. All rights reserved.

Antimutagenic effect of Lentinula edodes (BERK.) Pegler mushroom and possible variation among lineages

This study was performed to evaluate the efficiency of four different lineages (95/01, L1, 96/22 and JABK) of Lentinula edodes (BERK.) Pegler mushroom (shiitake) for inhibiting the N-ethyl-N-nitrosourea (ENU) clastogenicity in vivo. Male Swiss mice (10 animals/group) were treated during 15 consecutive days with dried mushroom added to basal diet under three different concentrations (1, 5 and 10%). At day 15, mice were intraperitoneally injected with ENU (50 mg/kg body weight) and sacrificed 24 h later for evaluation of micronucleated bone marrow polychromatic erythrocytes (MNPCE). Negative and positive controls (10 animals each), receiving basal diet and saline or ENU ip injection, respectively, were also evaluated. Results showed that pretreatments with diets containing the lineages 95/01, L1 and 96/22 reduce the frequencies of MNPCE induced by ENU. The absence of an antimutagenic activity for the lineage JABK might be related to intrinsic differences among the lineages such as biochemical composition. Taken together, our data show that the differences in protective activities of the mushrooms need to be clarified in further studies and the mechanisms for such activities need to be investigated. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

In vivo assessment of DNA damage and protective effects of extracts from Miconia species using the comet assay and micronucleus test

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A new model for tubular fluorescent lamps operated at high frequencies for dimmable applications

This paper presents a new static model for tubular fluorescent lamps (T12 bulb) operated at high frequencies. The main goal of this paper is to investigate the effects of ambient temperature and nominal switching frequency of operation in the static characteristics of tubular fluorescent lamps. The methodology for obtaining the model is based on several two-dimensional mathematical regressions, used to provide the behavior of the fluorescent lamp according to different independent variables, namely: power processed through the lamp and ambient temperature. In addition, the proposed model can be easily converted to a lamp equivalent resistance model, which can be useful for ballast designers. Finally, the curves obtained using the new model are compared to the correspondent experimental data, in order to verify the accuracy of the proposed methodology.

First in vivo evaluation of the mutagenic effect of Brazilian green propolis by comet assay and micronucleus test

Propolis is a hive product containing chiefly beeswax and plant-derived substances such as resin and volatile compounds. Propolis has been used in various parts of the world as an antiseptic and wound healer since ancient times, and interest in the product has recently increased. Considering the lack of data concerning the in vivo mutagenicity of green propolis, the capacity of this natural product to cause damage to the DNA was evaluated, using the alkaline single-cell gel electrophoresis (SCGE) and micronucleus test, in the peripheral blood cells of mice. The doses tested by gavage were 1000, 1500 and 2000 mg/kg. Micronucleus and SCGE assays showed that green propolis caused an increase in the damage to DNA in the peripheral blood cells of mice. The polychromatic: normochromatic erythrocytes ratio was not statistically different from the negative control. Considering the doses and the results obtained in this study, the acute consumption of green propolis produced some mutagenic effects on the blood cells of mice. (C) 2008 Elsevier Ltd. All rights reserved.

Antigenotoxicity and antimutagenicity of lycopene in HepG2 cell line evaluated by the comet assay and micronucleus test

Epidemiological studies have provided evidence that high consumption of tomatoes effectively reduces the risk of reactive oxygen species (ROS)-mediated diseases such as cancer. Tomatoes are rich sources of lycopene, a potent singlet oxygen-quenching carotenoid. In addition to its antioxidant properties, lycopene shows an array of biological effects including antimutagenic and anticarcinogenic activities. In the present study, the chemopreventive action of lycopene was examined on DNA damage and clastogenic or aneugenic effects of H2O2 and n-nitrosodiethylamine (DEN) in the metabolically competent human hepatoma cell line (HepG2 cells). Lycopene at concentrations of 10. 25, and 50 mu M, was tested under three protocols: before, simultaneously, and after treatment with the mutagen, using the comet and micronucleus assays. Lycopene significantly reduced the genotoxicity and mutagenicity of H2O2 in all of the conditions tested. For DEN, significant reductions of primary DNA damage (comet assay) were detected when the carotenoid (all of the doses) was added in the cell culture medium before or simultaneously with the mutagen. In the micronucleus test, the protective effect of lycopene was observed only when added prior to DEN treatment. In conclusion, our results suggest that lycopene is a suitable agent for preventing chemically-induced DNA and chromosome damage. (C) 2007 Elsevier Ltd. All rights reserved.

Allelic Frequencies of HPA-1 to 5 Human Platelet Antigens in Patients Infected With Hepatitis C Virus

Studies have suggested that hepatitis C virus (HCV) may infect not only hepatocytes but may also be carried by platelets. Platelets express more than 20 polymorphic antigenic determinants on their surface, which are called human platelet antigens (HPA), To determine the allele frequency of the HPA-1 to -5 in patients infected with HCV, blood samples were collected from 257 blood donors for the control group and from 191 patients infected with HCV. DNA was isolated and amplified for genes HPA-1 to -4 using PCR Sequence Specific Primers (PCR-SSP) and HPA-5 using PCR-Restriction Fragment Length Polymorphism (PCR-RFLP). The allelic and genotypic frequency of HPA-5a in patients infected with HCV was found to be significantly lower(P < 0.05) than in the controls, and HPA-5b from patients infected with HCV was significantly higher (P < 0.05) than in controls. The increase in HPA5b allelic frequency in HCV infection may indicate a possible association between HCV infection and HPAs. J. Med. Virol. 81:757-759, 2009. (C) 2009 Wiley-Liss, Inc.

Antimutagenic effect of Agaricus blazei Murrill mushroom on the genotoxicity induced by cyclophosphamide

Agaricus blazei Murrill extracts have previously been shown to have anticarcinogenic and antimutagenic proper-ties. These results suggest that antimutagenic activity, besides the modulation of the immune system, might be involved in the anticarcinogenic action of A. blazei. To investigate the possible antimutagenic effect of A. blazei in vivo, we evaluated its effect on clastogenicity induced by cyclophosphamide (CP) in mice, using the micronucleus test in bone marrow (MNPCE) and in peripheral blood (MNRET). Male Swiss mice were treated with CP (25 or 50 mg/kg i.p.) or with CP plus mushroom solution at three different temperatures: 4, 21, and 60 degreesC. Aqueous solution of a mixture from various lineages of the mushroom inhibited induction of micronuclei by CP in bone marrow and in peripheral blood of mice. In contrast to the mixture of lineages, a single isolated lineage did not lead to a reduction of CP-induced MN frequencies in either bone marrow or blood cells of mice. The results suggest that under certain circumstances these mushrooms exhibit antimutagenic activities that might contribute to an anticarcinogenic effect. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Antigen otoxicity of Agaricus blazei mushroom organic and aqueous extracts in chromosomal aberration and cytokinesis block micronucleus assays in CHO-k1 and HTC cells

Agaricus blazei (Ab) has become popularly known for its medicinal properties. Scientifically, it has been tested with regard to its capacity to protect genetic material against damage. We examined different organic extracts (methanolic extract-ME, hexanic extract-HE and n-butanolic extract-BE) and an aqueous extract (AE) of Ab, for their capacity to induce DNA damage as well as for their protective effect. Genetic damage was determined by the chromosomal aberration assay (CA) in CHO-k1 cells for all extracts and the cytokinesis block micronucleus assay (CBMN) in non drug-metabolizing (CHO-k1) and drug-metabolizing (HTC) cell lines for extract BE only. The extracts did not show clastogenicity but showed anticlastogenicity. The greatest percent reduction obtained were with BE (105%) and AE (126%) treatments in CA. BE treatment did not display genotoxicity in CHO-k1, but was genotoxic in HTC. However, BE was shown to be antigenotoxic causing decreased micronucleus frequency in HTC and CHO-k1 cells. These results suggest that all the extracts contained protective substances, but in some cases they could show a genotoxic effect with regard to metabolism. Therefore, these findings warrant caution in the use of this mushroom by the population. (c) 2005 Elsevier Ltd. All rights reserved.

Antimutagenic effects of the mushroom Agaricus blazei Murrill extracts on V79 cells

Agaricus blazei Murrill, a native mushroom in Brazil, has been widely consumed in different parts of the world due to its medicinal power. Its anticarcinogenic activity has been shown in experimental animals, and antimutagenic activity has been demonstrated only in Salmonella. In this work, the multagenic and antimutagenic activities of mushroom teas of strains AB96/07, AB96/09 and AB97/11 were evaluated in Chinese hamster V79 cells, using the comet assay and the micronucleus test. The cells were treated with three different concentrations (0.05, 0.1 and 0.15) of teas prepared from a 2.5% aqueous solution, under three different temperatures: (1) room (20-25 degreesC); (2) ice-cold (2-8 degreesC); and (3) warm (60 degreesC). The teas were applied in co-, pre- and post-treatments in combination with the mutagen methyl methanesulfonate (MMS; 1.6 x 10(-4) and 4 x 10(-4) M). The duration of the treatment was 1 h in the comet assay and 2 h in the micronucleus test. The results showed that the mushroom was not mutagenic itself. Nevertheless, the mushroom is an efficient antimutagen against the induction of micronuclei by MMS in all concentrations and preparations tested. The observed reductions in the frequencies of micronuclei ranged from 61.5 (room temperature 0.1% tea in post-treatment) to 110.3% (co-treatment with warm and ice-cold 0.15% tea). In the comet assay, the antimutagenic activity was detected only when the cells were pre-treated with the following teas: warm 0.1 and 0.15%, room temperature 0.05% and ice-cold 0.1%. The results indicate that the mushroom A. blazei extracts are antimutagenic when tested in V79 cells. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Letinula edodes (Berk.) Pegler (Shiitake) modulates genotoxic and mutagenic effects induced by alkylating agents in vivo

We evaluated the antimutagenic effect of Letinula edodes (Berk.) Pegler (Shiitake) on the frequency of micronuclei in mice treated with N-ethyl-N-nitrosourea (ENU) or cyclophosphamide (Cl?). Mice were orally (gavage) pretreated for 15 consecutive days with solutions of Shiitake (0.6 ml per day, gavage) prepared at three different temperatures: 4, 21 (RT), and 60 degreesC. Then, the animals were intraperitoneally injected on day 15 with CP (25 or 50 mg/kg) or ENU (50 mg/kg) and killed 24 or 48 h after treatment for evaluation of micronucleated polychromatic erythrocytes (MNPCEs) in bone marrow and micronucleated reticulocytes (MNRETs). A mixture of L. edodes lineages (LE 95/016, 96/14, 96/17, 96/22, 96/23, 97/27, and 97/28) significantly decreased the frequencies of MNPCEs and MNRETs induced by CP (25 and 50 mg/kg). When a single lineage from the mixture (LE 96/17) was tested we also found a significant reduction in the frequencies of MNPCEs and MNRETs induced by both CP or ENU (50 mg/kg). The comet assay was also performed 3 h after ENU treatment using mice pretreated with the single lineage (LE 96/17) of L. edodes. The results showed a high degree of variability with some indications of an antigenotoxic effect. Taken together, our data show that solutions from Shiitake inhibit in vivo mutagenicity of CP and ENU. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Cocaine mutagenicity and hepatocarcinogenicity evaluations in rodents

The mutagenicity (clastogenicity) and the carcinogenicity (promoting potential) of cocaine were evaluated, respectively, by the mouse bone marrow micronucleus test (study I) and by the initiated rat liver bioassay (study II). In study I, two administration routes (i.p. and i.v.) and two sampling times (24 and 48 hours) after cocaine treatment were studied. Swiss male mice were treated with cocaine at doses of 0, 18, 37, and 75 mg/kg and 0, 2, 4, and 8 mg/kg by i.p. and i.v. routes, respectively. No significant differences were observed between treated and negative control groups regarding the frequencies of micronuclei and the polichromatic/normochromatic erythrocyte (PCE/NCE) ratios. In study II, the development of putative preneoplastic foci of hepatocytes expressing the enzyme glutathione S-transferase placental form (GST-P+) was utilized as the end-point marker in a 8-week rat liver bioassay. The animals were initiated for carcinogenesis by a single i.p. sub-carcinogenic dose of diethylnitrosamine (DEN). After a 6-week exposure to 5 or 10 mg/kg of cocaine i.v. twice a week there was no enhancement of GST-P+ foci development above the values of the control DEN-only treated animals. Also, cocaine did not induce any toxicity as evidenced by the absence of alterations of rat body and liver weights and of liver biochemical function and morphology. The results suggest that cocaine does not have a mutagenic effect on the mouse bone marrow cells or promoting activity on the rat hepatocarcinogenesis process. Teratogenesis Carcinog. Mutagen. 18:199-208, 1998. (C) 1998 Wiley-Liss, Inc.

Sewage sludge does not induce genotoxicity and carcinogenesis

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In vivo genotoxicity evaluation of a treated urban sewage sludge sample

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