• Environmental Analysis Health and Toxicology
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• 제20권4호통권51호
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• pp.365-374
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• 2005

Ambient air particulate matters are classified into two distinct modes in sire distribution, namely the coarse and fine particles. Correlation between high particulate concentration and adverse effect on human populations has long been recognized. However, the toxicology of these adverse efforts has not been clarified. We investigated the genotoxic effect of PM 2.5 collected from urban area in Seoul by comet assay (A549 cells), CBMN assay (CHO-K1 cells) and EROD-microbioassay (H4IIE cells). Results from in vitro micronucleus assay and comet assay showed that PM 2.5 samples collected from traffic area, residential area and indoor air induced chromosomal damage and DNA breakage in a non-cytotoxic dose. The complex mixture effect of these PM 2.5 extracts was quantified by EROD-microbioassay in terms of its bio-TEQ (biologiral -TCDD equivalent concentration) which was 70.87$\pm$28.07, 93.55$\pm$21.80 and 14.31 $\pm$ 1.10 ng/g-PM 2.5 in traffic area, residental area and indoor air samples, respectively. Conclusively, we suggested that PM 2.5 collected from traffic area and residential area contains CYPIA inducer and genotoxic materials.

• Environmental Analysis Health and Toxicology
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• 제28권
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• pp.3.1-3.8
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• 2013

Objectives We investigated the genotoxic effects of 40-59 nm silver nanoparticles (Ag-NPs) by bacterial reverse mutation assay (Ames test), in vitro comet assay and micronucleus (MN) assay. In particular, we directly compared the effect of cytochalasin B (cytoB) and rat liver homogenate (S9 mix) in the formation of MN by Ag-NPs. Methods Before testing, we confirmed that Ag-NPs were completely dispersed in the experimental medium by sonication (three times in 1 minute) and filtration ($0.2{\mu}m$ pore size filter), and then we measured their size in a zeta potential analyzer. After that the genotoxicity were measured and especially, S9 mix and with and without cytoB were compared one another in MN assay. Results Ames test using Salmonella typhimurium TA98, TA100, TA1535 and TA1537 strains revealed that Ag-NPs with or without S9 mix did not display a mutagenic effect. The genotoxicity of Ag-NPs was also evaluated in a mammalian cell system using Chinese hamster ovary cells. The results revealed that Ag-NPs stimulated DNA breakage and MN formation with or without S9 mix in a dose-dependent manner (from $0.01{\mu}g/mL$ to $10{\mu}g/mL$). In particular, MN induction was affected by cytoB. Conclusions All of our findings, with the exception of the Ames test results, indicate that Ag-NPs show genotoxic effects in mammalian cell system. In addition, present study suggests the potential error due to use of cytoB in genotoxic test of nanoparticles.

• Environmental Analysis Health and Toxicology
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• 제19권4호
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• pp.335-344
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• 2004

Diesel exhaust particle (<2.5 ${\mu}{\textrm}{m}$, DEP$_{2.5}$) is known to be probarbly carcinogenic (IARC group 2A). DEP$_{2.5}$ contains organic compounds such as polycyclicaromatic hydrocarbon (PAH), heterocyclic compounds, phenols, and nitroarenes. Reactive oxygen species (ROS) are generated by DEP$_{2.5}$ without any biological activation system. Therefore, an alternative mechanism by which DEP$_{2.5}$ could be carcinogenic is known by the generation of oxidative DNA damage. The aim of this study was to investigate genotoxic effects of DEP$_{2.5}$ using single cell gel electrophoresis. In order to evaluate the mechanisms of DEP$_{2.5}$ genotoxicity, the rat micro-some mediated and DNA repair enzyme treated comet assays together with routine comet assay were performed. DEP$_{2.5}$ was collected from diesel engine bus and dichloromethane extract was obtained. The organic extract of DEP$_{2.5}$ revealed DNA damage itself in NIH/3T3 cells. And it showed both oxidative and microsome mediated DNA damages. 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. Our results show that DEP$_{2.5}$ are genotoxic and a great source of oxidative stress, but antioxidants can significantly reduce oxidative DNA damages. And DEP$_{2.5}$ may contain indirect mutagens which can be inhibited by CYP inhibitors.d by CYP inhibitors.

• Toxicological Research
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• 제20권3호
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• pp.225-232
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• 2004

The suitability of the single cell gel electrophoresis (SCGE) assay as a test for the monitoring of genotoxicity of aquatic environment was evaluated. The SCGE assay was employed to detect DNA damage induced in clam (Spisula sachalinensis) exposed to a direct mutagen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or an indirect mutagen, benzo[a]pyrene (B[a]P). The cells of gill and digestive glands were isolated from clam by homogenization, which was the optimized cell dissociation method, and the level of DNA damage was assessed and expressed as mean tail length. In the gill cells, significant dose- and time-dependent increase was observed in the mean tail length at the concentration from 0.01 to 0.5 ppm MNNG for 96 h. The linear correlation between relative dam-age index (RDI) values was suggested to provide criteria of genotoxicity monitoring for direct acting mutagen. The dose- and time-dependent responses of the digestive glands cells were less sensitive than those of the gill cells. In contrast, the genotoxic response resulting from the exposure of 0.01～1.0 ppm B[a]P to clam revealed a higher sensitivity in the digestive glands cells than the gill cells. The comparison between the time profiles of genotoxic responses in clam and carp, the latter had been obtained in our previous study, indicated that the metabolism of genotoxic compounds in the two aquatic organisms were quite different each other. We conclude that the SCGE assay has the potential as a screening test for routine genotoxicity monitoring of aquatic organisms because of its higher sensitivity and simplicity.

• 한국식품영양과학회지
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• 제32권7호
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• pp.1071-1075
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• 2003

차가버섯 분획물의 항산화활성과 유전독성 억제효과를 규명하기 위하여 차가버섯으로부터 조다당, 불용성 조다당 I과 II를 각각 추출하였으며 그 여액에서 저분자 물질과 에틸 아세테이트, 물 분획물을 얻었다. 얻어진 시료들은 DPPH free radical 소거능으로 항산화 활성을 측정하였으며, 마우스를 이용한 소핵실험으로 유전독성 억제효과를 검토하였다. 실험결과, 에틸 아세테이트 분획물의 RC$_{50}$ 이 46.5 $\mu\textrm{g}$으로 월등히 높았으며, 물 분획물과 수용성 다당도 각각 78.3$\mu\textrm{g}$과 77.4$\mu\textrm{g}$으로 다른 분획물에 비해 높은 항산화 효과를 나타내었다. 그리고 유전독성 억제효과에서는 양성대조군에 비하여 최고 농도인 80 mg/mg에서 저분자 물질과 에틸 아세테이트 분획물, 물 분획물, 수용성 다당 그리고 불용성 다당 I 및 II에서 각각 63.9%, 72.2%, 63.9%, 88.9%, 80.6% 그리고 81.5%의 소핵생성 억제효과를 나타내었으며 다당 분획물들이 80% 이상의 높은 억제율을 나타내었다.

• Archives of Pharmacal Research
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• 제21권4호
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• pp.363-369
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• 1998

Glutathione S-transferase placental form (GST-P) positive foci development and its expression in liver exposed by nongenotoxic carcinogens phenobarbital (PB) and clofibrate (CF), and genotoxic carcinogen 2-amino-3-methylimidazo[4,5-f] quinoline (IQ) were investigated as a measure of carcinogenic potential of these chemicals. Male F344 rats were initially given a single intraperitioneal injection of diethyinitrosamine (200 mg/kg), and 2 weeks later, animals were fed diets containing 0.03% IQ or 0.5% CF or 0.05% PB or basal diet as a control for 6 weeks. All rats were subjected to two-thirds partial hepatectomy (PH) at week 3. Sequential sacrifice of rats was performed at 8 weeks or 52 weeks, and liver tissues were examined for immunohistochemical staining of GST-P positive foci. The numbers (No./$cm^2$) and areas ($mm^2$/ $cm^2$) of GST-P positive foci were increased by IQ or PB, but were decreased by CF compare to the control. Consistent with the development of GST-P positive foci, a time-related increase in the expression of GST-P mRNA was found in the rats treated with IQ, whereas CF decreased it. The incidence of hepatocellular carcinoma at 52 weeks was increased by all three chemicals. These results show that PB and IQ induced GST-P positive foci, but the peroxisome proliferator CF did not, which suggest that the prediction of carcinogenic potency based on the development of prenoplastic foci may cause false negative in a particular category compounds like peroxisome proliferators.

• 한국환경성돌연변이발암원학회지
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• 제23권2호
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• pp.56-62
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• 2003

The liver progenitor cells could form a potential target cell population fore both tumor-initiating and -promoting chemicals. Induction of drug-metabolizing and antioxidant enzymes, including AhR-dependent CYP1A1, NQO-1 and AKR1C9, was detected in the rat liver epithelial WB-F344 "stem-like" cells. Additionally, WB-F344 cells express a functional, wild-type form of p53 protein, a biomarker of genotoxic events, and connexin 43, a basic structural unit of gap junctions forming an important type of intercellular communication. In this cellular model, two complementary assays have been established for detection of the modes of action associated with tumor promotion: inhibition of gap junctional intercellular communication (GJIC) and proliferative activity in confluent cells. We found that the PAHs and PCBs, which are AhR agonists, released WB-F344 cells from contact inhibition, increasing both DNA synthesis and cell numbers. Genotoxic effects of some PAHs that lead to apoptosis and cell cycle delay might interfere with the proliferative activity of PAHs. Contrary to that, the nongenotoxic low-molecular-weight PAHs and non-dioxin-like PCB congeners, abundant in the environment, did not significantly affect cell cycle and cell proliferation; however both groups of compounds inhibited GJIC in WB-F344 cells. The release from contact inhibiton by a mechanism that possibly involves the AhR activation, inhibition of GJIC and genotoxic events induced by environmental contaminants are three important modes of action that could play an important role in carcinogenic effects of toxic compounds. The relative potencies to inhibit GJIC, to induce AhR-mediated activity, and to release cells from contact inhibition were determined for a large series of PAHs and PCBs and their metabolites. In vitro bioassays based on detection of events on cellular level (deregulation of GJIC and/or proliferation) or determination of receptor-mediated activities in both ?$stem-like^{\circ}{\times}$ and hepatocyte-like liver cellular models are valuable tools for detection of modes of action of polyaromatic hydrocarbons. They may serve, together with concentration data, as a first step in their risk assessment.

• Toxicological Research
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• 제24권1호
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• pp.37-44
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• 2008

The in vitro cell transformation assays (CTA) were performed using BALB/3T3 murine fibroblasts and HaCaT human keratinocytes in order to evaluate concordance between both in vitro CTAs and carcinogenicity with compounds differing in their genotoxic and carcinogenic potential. Six test articles were evaluated, two each from three classes of compounds: genotoxic carcinogens (2-amino-5-nitrophenol and 4-nitroquinoline-N-oxide), genotoxic noncarcinogens (8-hydroxyquinoline and benzyl alcohol), and nongenotoxic carcinogens (methyl carbamate and N-nitrosodiphenylamine). Any foci of size $\geq$2 mm regardless of invasiveness and piling was scored as positive in CTA with BALB/3T3. As expected, four carcinogens regardless of their genotoxicity had positive outcomes in two-stage CTA using BALB/3T3 cells. However, of the two genotoxic noncarcinogens, benzyl alcohol was positive CTA finding. We concluded that, of the 6 chemicals tested, the sensitivity for BALB/3T3 system was reasonably high, being 100%. The respective specificity for BALB/3T3 assay was 50%. We also investigated the correlation between results of BALB/3T3 assay and results from HaCaT assay in order to develop a reliable human cell transformation assay. However, evaluation of staining at later time points beyond the confluency stage did not yield further assessable data because most of HaCaT cells were detached after $2{\sim}3$ days of confluency. Thus, after test article treatment, HaCaT cells were split before massive cell death began. In this modified protocol for this HaCaT system, growing attached colonies were counted instead of transformed foci 3 weeks since last subculture. Compared to BALB/3T3 assay, HaCaT assay showed moderate low sensitivity and high specificity. Despite these differences in specificity and sensitivity, both cell systems did exhibit same good concordance between in vitro CTA and rodent carcinogenicity findings (overall 83% concordant results). At present the major weakness of these in vitro CTA is lack of validation for regulatory acceptance and use. Thus, more controlled studies will be needed in order to be better able to assess and quantitatively estimate in vitro CTA data.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2002년도 학술발표대회
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• pp.100-100
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• 2002

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.185-185
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• 2005