• Environmental Mutagens and Carcinogens
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• v.22 no.2
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• pp.83-89
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• 2002

The single cell gel electrophoresis (comet) assay is one of the useful tools for the study of genetic damage in humans exposed to environmental mutagens and carcinogens. This study was undertaken to evaluate the status of DNA damage in peripheral lymphocytes depending on their sex, age, smoking habits, and other factors in normal healthy Korean population. The 99 volunteers included in the study and out of these, 36 volunteers were smoker and 63 volunteers were non-smoker aged between 20-59 years. All individual answered a questionnaire that assessed their general information including smoking habits and the extent of the environmental tobacco smoke (ETS) exposure, and blood samples were obtained. There was a statistically significant difference in the extent of DNA damage between smoker and non-smoker (p<0.001). A significant difference was also observed between male and female (p<0.001) and amongst the different group of age (p<0.005), however, correlation analysis showed that only smoking habit was a significant factor for DNA damage. No significant effect of smoking duration, number of cigarettes smoking a day, SPY (smoke pack years) in smokers and environmental tobacco smoke exposure in non-smokers on the status of DNA damage was observed.

• Toxicological Research
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• v.29 no.1
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• pp.43-52
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• 2013

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 ${\mu}M$) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 ${\mu}M$). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

• Journal of the Korean Society of Food Culture
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• v.19 no.3
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• pp.251-258
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• 2004

The changes in DNA damage were investigated during storage after irradiation. Potato, garlic were irradiated at 0.05, 0.07, 0.1 and 0.15 kGy and stored for 3 months. Ginger was irradiated at 0.01, 0.02, 0.03, 0.04 and 0.05 kGy and stored for 1 month. The comet assay was applied to the sample immediately after irradiation and at the end of storage. Samples were isolated, grounded and the suspended cells were embedded in an agarose layer. After lysis of the cells, they were electrophoresed for 1 min. and then stained. DNA fragmentation in seeds caused by irradiation was quantified as tail length and tail moment (tail length ${\times}%$ DNA in tail) by comet image analyzing system. Right after irradiation, the differences in tail length between unirradiated and irradiated samples were significant(p<0.05) in potato, garlic and ginger. With increasing the irradiation doses, statistically significant longer extension of the DNA from the nucleus toward anode was observed. The results represented as tail moment showed similar tendency to those of tail length. Similarly in the stored samples, even 1 or 3 months after irradiation, all the irradiated samples significantly showed longer tail length than the unirradiated controls. These results indicate that the comet assay could be one of the simple methods of detecting irradiated samples. Moreover, the method could detect DNA damage even after 1 or 3 months after irradiation.

• Journal of Nutrition and Health
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• v.36 no.3
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• pp.255-261
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• 2003

Food irradiation has been steadily increasing in many countries in line with increasing international trade and concerns about naturally occurring harmful contaminants in food. Although irradiation provides an excellent safeguard for the consumer by destroying almost 100% of harmful bacteria, it is necessary to ensure the safety of irradiated foods. This study was performed to investigate the effect of an irradiated diet on lipid peroxidation in the plasma, liver, small intestinal mucosa, and lymphocyte DNA damage in mice. Eight-week old ICR mice were assigned to two groups to receive either non-irradiated or irradiated (10 kGy) diets containing 20.38% fish powder and 6.06% sesame seeds for 4 weeks. The resulting changes in the degrees of lipid peroxidation were evaluated based on the level of plasma and liver thiobarbituric acid reactive substance (TBARS), transmission electron micrograph of jejunal mucosa, and free radical-induced oxidative DNA damage in lymphocytes, as measured by alkaline comet assay (single cell gel electrophoresis). The peroxide values of the gamma irradiated diet were measured every week, and the sample for comet assay was taken at the end of the four week experimental period. There was no significant difference in food efficiency ratio between the two groups. The peroxide values of the diet were immediately increased to 35.5% after gamma irradiation and kept on increasing during storage. After 4 weeks, no differences in tissue or plasma TBARS value were observed between the two groups, but epithelial cells of jejumum showed osmiophillic laminated membranous structures, considered as myelin figures,. The oxidative DNA damage expressed as tail moment (TM) increased 30% in the blood lymphocytes of the mice fed the irradiated diet. In conclusion, the comet assay sensitively detected differences in lymphocyte DNA damage after feeding with the irradiated diet for 4 weeks. However, in order to ensure the safety of irradiated foods, it would be more useful to conduct a long-term feeding regimen using an irradiated diet and examine the level of lipid peroxidation and the state of oxidative stress in a greater range of organs.

• Toxicological Research
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• v.23 no.1
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• pp.25-31
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• 2007

To evaluate the protective effect of Houttuynia cordata on hydrogen peroxide-induced oxidative DNA damage in HepG2 cell line, we used an alkaline single-cell gel electrophoresis (SCGE; comet assay). The DNA damage was analyzed by tail moment (TM) and tail length (TL), which used markers of DNA strand breaks in SCGE. The $100{\mu}g/ml$ of methanolic extract of Houttuynia cordata root showed significant protective effects (p < 0.01) against hydrogen peroxide-induced DNA damage in HepG2 cells and increased cell viability against hydrogen peroxide. The results of this study indicate that Houttuynia cordata root methanol extract acts as a potential antioxidant, and exhibits potential anticancer properties, which may provide a clue to find applications in new pharmaceuticals for oxidative stability.

• Environmental Analysis Health and Toxicology
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• v.20 no.4 s.51
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• pp.333-341
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• 2005

In order to know whether polychaetes could be used as an appropriate organism for the detection of genotoxicity, DNA strand breaks were evaluated in blood cells of a nereidae worm (Perinereis aibuhitensis) exposed to various aquatic chemical pollutants (e.g. Cd, Pb, Pyrene, Benaor[a]pyrene). Hydrogen peroxide increased DNA strand breaks up to the highest concentration (10 $\mu$M). Higher concentration than 0.1 $\mu$M showed a significantly more DNA damage than control. Cadmium and lead also showed higher DNA damage than control, over 1.0 and 1 $\mu$g/L, respectively. In case of pyrene, DNA damage was detected even at 0.001 $\mu$g/L. However, DNA damage decreased due to apoptosis at the highest concentration of pyrene and Pb. This study suggested that the polythaetous blood cells could be used effectively for screening genotoxic contaminants in the environment.

• CELLMED
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• v.3 no.3
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• pp.22.1-22.10
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• 2013

Traditional Chinese medicine (TCM) in single herb or formula prescription has been used for thousands of years. Many of them possess antioxidant activity and the activity may contribute the therapeutic effect. This paper would review the relationship of traditional herbal medicine and antioxidant with particular reference to ginseng. This medicinal herb has been used worldwide with extensive tonic effect. The comet assay, a technique for DNA protecting and damaging investigation would be introduced and the application of comet assay on TCM would be discussed.

• Environmental Analysis Health and Toxicology
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• v.16 no.1
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• pp.17-20
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• 2001

The alkaline comet assay, employing a single-cell gel electrophoresis(SCGE), is a rapid, simple and sensitive technique for visualizing and measuring DNA damage leading to strand breakage in individual mammalian cells. The protecting effect of pretreatment with vitamin C and cysteine on the DNA damage of gamma ray was investigated in mice splenic lymphocytes. Vitamin C and cysteine were administered orally for five consecutive days before irradiation. Four week old ICR male mice were irradiated wish 3.5Gy of γ-radiation and were sacrificed 3 days later. Spleens were taken for DNA damage examination by Comet assay and the tail moments of DNA single -strand breaks in tole splenic lymphocytes were evaluated. The results show that pretreatment with vitamin C and cysteine were effective in protecting against DNA damage by gamma ray. Administration of antioxidants like vitamin C and cysteine to mice before irradiation was effective in reducing the tail moment of splenic lymphocytes DNA.

• Korean Journal of Medicinal Crop Science
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• v.11 no.2
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• pp.89-96
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• 2003

Korean mistletoes extracts were investigated for in vitro antioxidation activity, with 1,1-diphenyl-2-picrylhydrazine(DPPH), and an inhibitory effect on oxidative DNA damage by using comet assay. The Korean mistletoes were 4 different kinds classified by their host plants (Korean Viscum sp. in Quercus acutissima Carr., Korean Viscum sp. in Castanea crenata, Korean Viscum sp. in Betula platyphylla, and Korean Viscum sp. in Salix koreensis). The samples were extracted with ethanol, and fractonationed with n-butanol, ethyl acetate, chloroform, n-hexane, and second distilled water. Among them, ethyl acetate fraction from Korean Viscum sp. in Betula platyphylla showed the strongest activities to electron donating ability on 1,1-diphenyl-2-picrylhydrazyl(DPPH) and the protective effect on oxidative DNA damage.

• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.127-138
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• 2006

In urban areas, diesel exhaust particles (DEP) are probably a major component of particulate matters, especially in Korea where drive many diesel vehicles. The aim of this study was to investigate genotoxic effects of DEP using single ceil gel electrophoresis. In order to evaluate the mechanisms of DEP genotoxicity, the rat microsome mediated and DNA repair enzyme treated comet assays together with conventional comet assay were performed. Total diesel particles (DEPT) was collected without site fractionation from diesel engine bus and dichloromethane extract was obtained. The organic extract of DEPT revealed DNA damage itself in NIH/3T3 cells. The level of DNA breaks plus oxidative DNA lesions and microsome mediated DNA damage was assessed by modified single cell gel eletrophoresis. DEPT was able to induce oxidative DNA damage as well as microsome mediated DNA damage. Vitamin C as an model antioxidant reduced DNA damage in endonuclase III treated comet assay. One of flavonoid, galangin as a CYP1A1 inhibitor. reduced DNA damage in the presence of S-9 mixture. $DEP_T$ is the sources of oxidative stress, but antioxidants can significantly reduce oxidative DNA dmage. And $DEP_T$ may contain indirect mutagens which can be inhibited by CYP1A1 inhibitors. The ethanol extracts of the mixed vegetables (BV) or the mixed fruits (BF) were evaluated for their in vitro antigenotoxic effects. BV and BF showed potent Inhibitory effects against DEPT induced DNA damage with oxidative DNA lesions and in the prescence of S-9 mixture. These results indicate that BV and BF could prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P4501A1 in cell culture.