• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3409-3416
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• 2012

Aim: It is well known that polycyclic aromatic hydrocarbons (PAHs) such as benzo (a) pyrene have carcinogenic properties and may cause many types of cancers in human populations. Genetic susceptibility might be due to variation in genes encoding for carcinogen metabolizing enzymes, such as cytochrome P-450 (CYP450). Our study aimed to investigate the effect of genetic polymorphisms of CYP1A1 (m1 and m2) on genetic damage in 115 coal-tar workers exposed to PAHs at their work place. Methods: Genetic polymorphisms of CYP1A1 were determined by the PCR-RFLP method. Comet and buccal micronucleus assays were used to evaluate genetic damage among 115 coal tar workers and 105 control subjects. Results: Both CYP1A1 m1 and CYP1A1 m2 heterozygous and homozygous (wt/mt+mt/mt) variants individually as well as synergistically showed significant association (P<0.05) with genetic damage as measured by tail moment (TM) and buccal micronuclei (BMN) frequencies in control and exposed subjects. Conclusion: In our study we found significant association of CYP1A1 m1 and m2 heterozygous (wt/mt)+homozygous (mt/mt) variants with genetic damage suggesting that these polymorphisms may modulate the effects of PAH exposure in occupational settings.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2199-2206
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• 2012

Background: Our objective was to evaluate the MTHFR C677T-A1298C polymorphisms in patients with breast cancer and in individuals with no history of cancer, to compare the levels of genetic damage and apoptosis under folic acid (FA) deficiency between patients and controls, and to assess associations with breast cancer. Methods: Genetic damage was marked by micronucleated binucleated cells (MNBN) and apoptosis was estimated by cytokinesis-block micronucleus assay (CBMN). PCR-RFLP molecular analysis was carried out. Results: The results showed significant associations between the MTHFR 677TT or the combined MTHFR C677T-A1298C and breast cancer risk (OR = 2.51, CI = 0.85 to 7.37, p = 0.08; OR = 4.11, CI = 0.78 to 21.8, p < 0.001). The MNBN from the combined MTHFR C677T-A1298C was higher and the apoptosis was lower than that of the single variants (p < 0.05). At 15 to 60 nmol/L FA, the MNBN in cases with the TTAC genotype was higher than controls (p < 0.05), whereas no significant difference in apoptosis was found between the cases and controls after excluding the genetic background. Conclusions: Associations between the combined MTHFR C677T-A1298C polymorphism and breast cancer are possible from this study. A dose of 120 nmol/L FA could enhance apoptosis in cases with MTHFR C677T-A1298C. Breast cancer individuals with the TTAC genotype may be more sensitive to the genotoxic effects of FA deficiency than controls.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.5229-5232
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• 2012

The incidence of malignant melanoma increases with age. One significiant effect of aging processes is an accumulation of oxidative damage in the genetical material. In this study, the relationship between malignant melanoma and damage in chromosomes and proliferative effectiveness of human peripheral lymphocytes were investigated by the micronucleus (MN) technique. A total of 15 malignant melanoma patients and appropriately matching 15 healthy controls were involved in the study. MN frequencies and proliferative indexes (PI) after non toxic levels of hydrogen peroxide treatment were also measured to determine damaging effect of oxidative stress in genome in addition to measuring the spontenous levels of micronuclei and PI. The patient group had a significantly higher rate of spontaneous MN than the control group (p<0.01). After treatment with $H_2O_2$, MN frequencies in the patient group was significantly decreased (p<0.01) although there was no difference between the treated and untreated results of control group (p=0.29). There was also difference (p<0.01) between the MN frequencies of the patient and the control group either in the spontaneous levels or in the $H_2O_2$ treated groups. The same significant difference persisted when the PI values were compared between patient and control groups. Increase in the MN frequency in patients could mean the alterations in the chromosomal structure which may lead to the chromosome instability and therefore genetic susceptibility to cancer. This increased number of micronuclei can also be used for cytological marker in identifying high risk cases for malignant melanoma.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.1071-1075
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• 2003

This study was performed to observe the antioxidative and genotoxic effect of the fractions from Inonotus obliquus using DPPH test and micronucleus assay. Stepwise fractionation of the ethanol extract from Inonotus obliquus was done by using hexane, chloroform, ethyl acetate, butanol and water to obtain effective fraction. Each fraction was tested in 1.5 ${\times}$ 10$^{-4}$ DPPH. Among six fractions, the ethyl acetate fraction showed the highest electron donating activities (46.5 $\mu\textrm{g}$/mL). The results on genotoxic effects on insoluble fractions and most of fractions showed cytotoxic effects more than 90% activity. These results suggest that some components contained in the Inonotus obliquus showed such activities and much more studies have to perform.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 1996.12a
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• pp.61-61
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• 1996

Taxol is used as cancer therapeutic agent. It has been known as weak posotive of chromosome aberration assay in vitro in our previous results (Ryu et al., 1996) and potent clastogens in the mouse bone marrow micronucleus (Tinwell and Ashby, 1994). We performed microgel electrophoresis to determine the effect of taxol and it's precursor 10-deacetyl baccatin III(DAB) on DNA. Microgel electrophoresis is useful, rapid, simple, visual, and sensitive technique for measuring DNA breakage and repair mechanisms in mammalian 근ells. The range of concentration used for taxol were 854, 427, 213.5, 106.8, 53.4 Ug/ml, for DAB 910 ,455, 227.5 U9/ml, Cell viability always exceed 85%. We analyzed the results by using the special software of image analyzer for this comet assay (Komet 3.0). By using this image analyzer software , we can get the result as the tail moment ((mean of tail length - mean of head lengh) x tail%DNA/100). A slight increase in DNA migration was observed for taxol at the concentration of 854 Ug/m4 in the absence of S9 mixture. No increased DNA migration was observed after treatment with DAB.

• Korean Journal of Veterinary Research
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• v.33 no.3
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• pp.487-492
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• 1993

정상인 말초혈액임파구 및 C57BL/6마우스 비장임파구에 $^{60}Co{\gamma}-rays$를 in vitro상태에서 조사한 후 500개 또는 1000개의 cytokinesis-blocked(CB) lymphocytes의 미세핵(micronuclei)의 발생빈도를 측정하였다. 방사선조사량에 따라 미세핵의 발생빈도는 증가하였으며 linear-quadratic model로 측정한 결과 선량반응곡선의 식은 인체의 경우 $Y=(0.31{\pm}0.049)D+(0.0022{\pm}0.0002)D^2+13.19$($r^2=1.000$)이었으며, 마우스의 경우 $Y=(1.31{\pm}0.264)D+(0.0015{\pm}0.0006)+8.7$($r^2=0.988$)이었다(Y는 1000개의 CB cell 당 미세핵발생빈도, D는 cGy로 표시되는 조사선량). 인체 말초혈액임파구에 대한 마우스 비장임파구의 상대적 생물학적 효과(relative biological effectiveness)는 미세핵의 발생율이 세포당 0.05~0.8의 범위에서 $1.84{\pm}0.48$이었다. 미세핵분석법은 인체 및 동물의 방사선 피폭시 간편하고 빠른 생물학적 선량측정법으로 사용될 수 있을 것이다.

• Korean Journal of Veterinary Research
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• v.44 no.3
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• pp.323-327
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• 2004

The purpose of the present experiment was to investigate the micronuclei(MN) frequency in cytokinesis-blocked(CB) cells after various doses of gamma-rays in pig (Landrace, male, 3-month-old) and so to contribute to the clarification of the question whether these species are suitable as a target organism in the test system. The frequencies of binucleated cells, and gamma-ray-induced MN in CB cells at several doses were measured in three donors. The peaks of binucleated lymphocyte formation(22%) were found at a concentration of 2% phytohaemagglutinin(PHA) and $4{\mu}g/ml$ Cytochalasin B(Cyt-B) in pig at 72 hours after incubation. Measurements performed after irradiation showed a dose-related increases in MN frequency in each of the donors studied. When analysed by linear-quadratic model the line of best fit was $y=0.0183D+0.0124D^2+0.0133$(y = number of MN/CB cells and D=irradiation dose in Gy). In conclusion, the results demonstrate that it appears feasible to use pig as target organisms in the micronucleus test to estimate the cytogenetic damage caused by ionizing radiations or, potentially, chemical compounds.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.374-382
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• 2011

We investigated the mutagenicity of methiozolin, newly developed herbicide, in vitro reverse mutation test using Salmonella typhimurium and Escherichia coli, chromosome aberration test using chinese hamster lung (CHL) cells and in vivo micronucleus test of mice. In the reverse mutation test, the methiozolin did not induce mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537, Escherichia coli WP2uvrA with and without metabolic activation at $5,000{\mu}g$/plate. In the chromosome aberration test, the results showed no incidence of increased structural and numerical chromosome abberrations at any doses tested (80, 40, $20{\mu}g$/mL). In micronucleous test, the ratio of micronuclei was measured in polychromatic erythrocytes with treated methiozolin for ICR mice. No incidence of increased micronuclei were observed in polychromatic erythrocytes (1,500, 1,000, 500 mg/kg). Based on these results, we concluded that methiozolin has no mutagenic toxicity in vitro and in vivo systems.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.152-152
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• 2003

As utilization of radiation in medicine, industry and biochemical research increases, the protection against radiation damage has become an important issue. Natural products such as herbal medicines are beginning to receive attention as modifiers on the radiation response. In the present study, the protective effect of a herb, Menthae Herba, against radiation-induced DNA damage was evaluated using alkaline single-cell gel electrophoresis (SCGE; comet assay) in the mouse peripheral blood Iymphocytes and the micronucleus formation test in the Chinese hamster ovary (CHO) cells. The tail moment, which was a marker of DNA damage in the SCGE, and the frequency of micronuclei was decreased in groups treated with Mentae Herba extract before exposure to 200 cGy of gamma-ray. We also confirmed its activities to scavenge DPPH and hydroxyl radicals. These experiments demonstrated that Menthae Herba was effective at reducing the radiation-induced damage of DNA and scavenging free radicals. It is plausible that scavenging of free radicals by Menthae Herba may have played an important role in providing the protection against the radiation-induced damage to the DNA. These results indicated that Menthae Herba might be a useful radioprotector and that radical scavenging appears to be one of the mechanisms of radiation protection.

• Food Science and Preservation
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• v.16 no.5
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• pp.782-788
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• 2009

The genotoxicological safety of gamma-irradiated egg white and yolk was examined to ensure that required safety parameters were met, and in an effort to further apply gamma-irradiation for improvement of the hygienic qualities of eggs. Egg white and yolk were irradiated at 20 kGy, much higher than the legally approved dose (less than 5 kGy), and possible genotoxicity was evaluated using in vitro and in vivo tests. The SOS chromotest employing Escherichia coli PQ37, and a chromosomal aberration test in cultured Chinese hamster lung (CHL) cells, were performed in vitro with or without metabolic activation (S9). An in vivo micronucleus development test was conducted using mouse bone marrow cells. Negative results were obtained in the SOS chromotest. The incidence of chromosomal aberration in CHL cells and the frequency of micronuclear developmentin mouse bone marrow cells treated with irradiated samples were not significantly different from those of non-irradiated controls. Thus, it may be concluded that up to 20 kGy of gamma irradiation applied to egg white and yolk did not show any genotoxic effects under our experimental conditions.