• Proceedings of the PSK Conference
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• 2001.04a
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• pp.156.2-156.2
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• 2001

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.167.1-167.1
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• 2003

The human exposure level of cadmium can be varied by environmental level of cadmium and individual life style. This study was conducted to estimate current exposure of cadmium using up-to date in Korea. The exposure estimates were intended to representative of the general adult group with 60kg. This study quantified human exposure level of cadmium through food, air and soil except water because domestic all data was not detected. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.296.2-296.2
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• 2002

Our previous study demonstrated that 2.3', 4.4'. 5- Pentachlorobiphenyl (PCB 118) showed an antiestrogenic activity in vitro and in vivo. In the present study. we examined the effect of PCB 118 on postnatal reproductive development in female rats. PCB 118 (0.001. 0.01 or 0.1 mg/kg/day) was administered to pregnant female SD rats from gestation day (GO) 6 to 18 via subcutaneous injection. and developmental parameters such as vaginal opening were determined. PCB 118 significantly delayed vaginal opening of female offsprings at dose of 0.1 ${\mu}g$/kg/day. whereas had no effects on body weights. In addition. in utero treatment of PCB 118 caused significant decreases in serum levels of E2, T3 and T4 in female oftsprings at certain doses on postnatal day (PND) 22. Our data of results indicate that in utero exposure to PCB 118 may postnatal reproductive development in female rat through its antiestrogenic activity.

• Toxicological Research
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• v.17
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• pp.237-239
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• 2001

China is an Asia country with population more than 1,200 millions. According to the national registration, the number Q[ chemicals commonly used in China reaches 80,000, and the number of chemicals produced in China is more than 30,000, about 10% of which has been evaluated for safety and has the toxicological data. Most of the chemicals still need safety evaluation and a part of chemicals need a renewed evaluation. At present. the information techniques and telecommunication network are develop-ing widely and intensively. It is used not only in different institutions and enterprises, but also in many governmental sectors in my country. Here is the introduction of the situation of information network on chemical safety with toxicological data and the work done by different institutions and governmental sectors in China.

• Toxicological Research
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• v.32 no.1
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• pp.9-14
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• 2016

The National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) provides validation support for US Federal agencies and the US Tox21 interagency consortium, an interagency collaboration that is using high throughput screening (HTS) and other advanced approaches to better understand and predict chemical hazards to humans and the environment. The use of HTS data from assays relevant to the estrogen receptor signaling data pathway is used as an example of how HTS data can be combined with computational modeling to meet the needs of US agencies. As brief summary of US efforts in the areas of biologics testing, acute toxicity, and skin sensitization will also be provided.

• Molecular & Cellular Toxicology
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• v.3 no.2
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• pp.98-106
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• 2007

Genotoxic stress triggers a variety of biological responses including the transcriptional activation of genes regulating DNA repair, cell survival and cell death. In this study, we investigated to examine gene expression profiles and genotoxic response in TK6 cells treated with DNA damaging agents MNNG (N-methyl-N'-nitrosoguanidine) and hydrogen peroxide $(H_2O_2)$. We extracted total RNA in three independent experiments and hybridized cRNA probes with oligo DNA chip (Applied Biosystems Human Genome Survey Microarray). We analyzed raw signal data with R program and AVADIS software and identified a number of deregulated genes with more than 1.5 log-scale fold change and statistical significancy. We indentified 14 genes including G protein alpha 12 showing deregulation by MNNG. The deregulated genes by MNNG represent the biological pathway regarding MAP kinase signaling pathway. Hydrogen peroxide altered 188 genes including sulfiredoxins. These results show that MNNG and $H_2O_2$ have both uniquely regulated genes that provide the potential to serve as biomarkers of exposure to DNA damaging agents.

• Molecular & Cellular Toxicology
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• v.4 no.3
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• pp.260-266
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• 2008

Recently, there has been scientific discussion on the utility of -omics techniques such as genomics, proteomics, and metabolomics within toxicological research and mechanism-based risk assessment. Toxicogenomics is a novel approach integrating the expression analysis of genes (genomic) or proteins (proteomic) with traditional toxicological methods. Since 1999, the toxicogenomic approach has been extensively applied for regulatory purposes in order to understand the potential toxic mechanisms that result from chemical compound exposures. Therefore, this article's purpose was to consider the utility of toxicogenomic profiles for improved risk assessment, explore the current limitations in applying toxicogenomics to regulation, and finally, to rationalize possible avenues to resolve some of the major challenges. Based on many recent works, the significant impact toxicogenomic techniques would have on human health risk assessment is better identification of toxicity pathways or mode-of-actions (MOAs). In addition, the application of toxicogenomics in risk assessment and regulation has proven to be cost effective in terms of screening unknown toxicants prior to more extensive and costly experimental evaluation. However, to maximize the utility of these techniques in regulation, researchers and regulators must resolve many parallel challenges with regard to data collection, integration, and interpretation. Furthermore, standard guidance has to be prepared for researchers and assessors on the scientifically appropriate use of toxicogenomic profiles in risk assessment. The National Institute of Toxicological Research (NITR) looks forward to an ongoing role as leader in addressing the challenges associated with the scientifically sound use of toxicogenomics data in risk assessment.

• Environmental Mutagens and Carcinogens
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• v.20 no.1
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• pp.21-25
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• 2000

Recently there is increasing interest in the use of structure activity relationships for predicting the biological activity of chemicals. The reasons for the interest include the decrease cost and time per chemical as compared with animal or cell system for identifying toxicological effects of chemicals and the reduction in the use of animals for toxicological testing. This study is to test the validity of the mutagenicity data generated from QSAR (Quantitative Structure Activity Relationship) program. Thirty chemicals, which had been evaluated by Ames test during 1997-1999, were assessed with TOPKAT QSAR mutagenicity prediction module. Among 30chemicals experimented, 28 were negative and 2 were positive for Ames test. On the contrary, 23 chemicals showed the high confidence level indicating high prediction rate in mutagenicity evaluation, and 7 chemicals showed the lsow to moderate confidence level indicating low prediction in mutagenicity evaluation. Overall mutagenicity prediction rate was 77% (23/30). The prediction rates for non-mutagenic chemicals were 79% (22/28) and mutagenic chemicals were 50% (1/2). QSAR could be a useful tool in providing toxicological data for newly introduced chemicals or in furnishing data for MSDS or in determining the dose in toxicity testing for chemicals with no known toxicological data.

• Environmental Mutagens and Carcinogens
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• v.26 no.1
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• pp.12-19
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• 2006

Cadmium, a human carcinogen, can induce toxicity in various cell lines and organs. Despite extensive research, the mechanisms of cadmium-induced cell toxicity and estrogenic potential in human are not clear. This study was performed to investigate cadmium-induced toxicity on human breast cancer cells: MCF-7 cells, an estrogen receptor (ER) positive breast cancer cells, and MDA-MB-231 cells, an ER negative breast cancer cells. MCF-7 cells was proved to be more sensitive than the other cell lines (IC50 = $50\;{\mu}M$ at MCF-7 cells and $120{\mu}M$ at MDA-MB-231). The expression of JNK and AP-1 transcription factors such as c-Jun and c-Fos dependent transcription were increased by cadmium treatment. Inhibition of ER activation by ER antagonist (tamoxifen or ICI 182,780) significantly recovered the viablity and inhibited apoptotic cell death. This suggested that cadmium-induced cell death in ER (+) cells was mediated by JNK/AP-1 pathway and this pathway was more stimulated by ER activated by cadmium. Co-treatment of antioxidants such as selenium (Se), butylated hydroxyanisole (BHA), glutathione (GSH), or N-acetyl-L-cysteine (NAC) recovered the cadmium-induced cell death in MCF-7 cells. Cadmium-induced lipid peroxidation was decreased by GSH, NAC, or BHA in MCF-7 cells. The expression of SOD protein was decreased by cadmium ($100{\mu}M$) but recovered by GSH, NAC, BHA, or Se. Our data showed that the cadmium-induced cell toxicity in human breast cancer cells could be protected by the antioxidants (Se, BHA, NAC, GSH, or NAC) and ER antagonist (tamoxifen or ICI 182,780). Therefore, toxicity of cadmium in breast cancer were mediated by oxidative stress and $ER{\alpha}$.

• Toxicological Research
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• v.20 no.1
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• pp.1-11
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• 2004

Evaluation of toxicological pathology is to some extend subjective judgments by pathologist and the accuracy of pathologist's works is based on the individual training and experiences. It has been required to establish a peer review system for toxicologic pathology and these review system has been employed by various practice of toxicological pathology. It would be pointed out that the possible causes of drifts in pathology are due to 1) lack of knowledge or experience of individual pathologists, 2) poorly maintained consistence of grading among animals in study, 3) different interpretation of findings between pathologists, or 4) pathology data processing. Example cases of diagnostic errors and current practice of peer review including tissue selection criteria, documentation and problem resolution for short-term and carcinogenicity studies were introduced. For sound regulatory system and high integrity of practice in toxicological pathology, current approaches of peer review system were reviewed.