• Molecular & Cellular Toxicology
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• v.2 no.4
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• pp.244-250
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• 2006

The detection of many synthetic chemicals used in industry that may pose a genetic hazard in our environment is of great concern at present. Since these substances are not limited to the original products, and enter the environment, they have become widespread environmental pollutants, thus leading to a variety of chemicals that possibly threaten the public health. In this respect, to regulate and to evaluate the chemical hazard will be important to environment and human health. The genotoxicity of 3 synthetic chemicals was evaluated in L5178Y $tk^{+/-}$ mouse lymphoma cells in vitro. 9H-carbazole (CAS No. 86-74-8) did not induce significant mutation frequencies both in the presence and absence of metabolic activation system. 1, 3-Dichloro-2-propanol (CAS No. 96-23-1) revealed a significant increase of mutation frequencies in the range of $625-373\;{\mu}g/mL$ in the absence of metabolic activation system and $157-79\;{\mu}g/mL$ in the presence of metabolic activation system. And also, fenpropathrin (CAS No. 64257-84-7) appeared the positive results only in the absence of metabolic activation system. Through the results of MLA tk assay with 3 synthetic chemicals in L5178Y cells in vitro, we may provide the important clues on the genotoxic potentials of these 3 chemicals.

• Molecular & Cellular Toxicology
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• v.2 no.4
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• pp.251-256
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• 2006

The exploration of genes which expressions are changed by exposure to ecotoxicants or pollutants can provide the important information about the reaction mechanisms in the body as well as adaptation to exterior stimulus or environmental changes. Also they can be developed as biomarkers for the detection of environmental pollution. Differential display polymerase chain reaction (DD-PCR) technique has been usefully used to hunt the clones which expressions are up-regulated or down-regulated by exterior changes and this study aimed to search for those clones in diesel oil-exposed rockfish (Sebastes schlegeli) using DD-PCR. The RNA isolated from liver of 20 ppb diesel oil-exposed rockfish was used for screening of the differentially displayed genes and total 44 differentially expressed genes (DEG) are detected then their nucleotide sequences were analyzed. The present data provided the general information about the effect of diesel oil contamination on marine organism and further more the primary step in development of new biomarkers for marine environmental pollution or ecotoxicological stresses.

• Molecular & Cellular Toxicology
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• v.2 no.2
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• pp.106-113
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• 2006

Phthalate analogues are a plasticizer and solvent used in industry. Phthalates were classified in the category of "suspected" endocrine disruptors. The purpose of our study was to screen and elucidate the endocrine disrupting activity of seven phthalate analogues. E-screen assay was performed in MCF-7 human breast cancer cells with seven phthalate analogues. In this cell proliferation assay, benzyl butyl phthalate (BBP) and dibutyl phthalate (DBP) showed high estrogenic activity. Their relative proliferation efficiencies (RPE) were 109 and 106%, respectively. In vitro estrogen receptor (ER) binding assay, BBP, di-n-octyl phthalate (DOP) and dinonyl phthalate (DNP) showed weak relative binding affinity (RBA: 0.02%) compared to $17{\beta}-estradiol\;(E2)$ (RBA: 100%). In uterotrophic assay, E2 produced a significant increase, whereas four tested phthalate analogues had potential estrogenic effects in vitro did not increased in uterus weight in immature rats. From these results, we demonstrated that phthalate analogues exhibit weak estrogenic activity in vitro assays at high concentrations. Although phthalates induced an increase in MCF-7 cell proliferation by an estrogenic effect, they could not induce a uterus weight increase in vivo. From these, we may suggest that these phthalate analogues are easily metabolized to inactive forms in vivo. Further investigation in other in vitro and in vivo experimental systems might be required.

• Molecular & Cellular Toxicology
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• v.2 no.2
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• pp.89-96
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• 2006

The detection of many synthetic chemicals used in industry that may pose a genetic hazard in our environment is of great concern at present. Since these substances are not limited to the original products, and enter the environment, they have become widespread environmental pollutants, thus leading to a variety of chemicals that possibly threaten the public health. In this respect, to regulate and to evaluate the chemical hazard will be important to environment and human health. The clastogenicity of 11 synthetic chemicals was evaluated in Chinese hamster lung fibroblast cells in vitro. 1-Chloro-3-bromopropane CAS No. 109-70-6) induced chromosomal aberrations with significance at the concentration of $185.0\;{\mu}g/mL\;and\;1,600\;{\mu}g/mL$ both in the presence and absence of metabolic activation system, respectively. Triphenyl phosphite (CAS No. 101-02-0), which is one of the most cytotoxic chemical among 11 chemicals tested revealed no clastogenicity in the range of $95.0-4.9\;{\mu}g/mL$ both in the presence and absence of metabolic activation system. From the results of chromosomal aberration assay with 11 synthetic chemicals in Chinese hamster lung cells in vitro, 1-chloro-3-bromopropane revealed a positive clastogenic result in this study.

• Molecular & Cellular Toxicology
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• v.2 no.4
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• pp.229-235
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• 2006

Volatile organic compounds (VOCs) are a major component of urban air pollution. It is documented that low exposure levels of VOCs induce alterations in immune reactivity resulting in a subsequent higher risk for the development of allergic reactivity and asthma. Despite these facts, there are few reports on the affected primary target and the underlying effective causal mechanisms. So in this study, to better understand the risk of BTX (benzene, toluene and o-xylene) which are the major VOCs and to identify novel biomarkers on immune response to these VOCs exposure in human T lymphocytes, we performed the toxicogenomic study by analyzing of gene expression profiles using 35 k human oligo-microarray. BTX generated specific gene expression patterns in Jurkat cell line. By clustering analysis, we identified some genes as potential markers on immuno-modulating effects of BTX. Four genes of these, HLA-DOA, ITGB2, HMGA2 and 5TAT4 were the most significantly affected by BTX exposure. Thus, this study suggests that these differentially expressed immune genes may play an important role in the pathogenesis on BTX exposure and have significant potential as novel biomarkers of exposure, susceptibility and response to BTC.

• Molecular & Cellular Toxicology
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• v.1 no.2
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• pp.124-129
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• 2005

Pro-inflammatory cytokines, such as tumor necrosis factor $(TNF)-{\alpha}$, interleukin-12 (IL-12) and interleukin $(IL-1)-{\beta}$, play a key role in causing inflammatory diseases, which are rheumatoid arthritis, Crohn's disease and sepsis. Accumulating evidences suggest that low level laser irradiation (LLLI) may have an anti-inflammatory action. However, there are few data regarding down regulation of Th1 immune response by using the diod typed laser emitting device for human patients. As a fundamental step in order to address this issue, we investigated immunological impact of the low level laser irradiation (10 mw laser diode with a wavelength of 630 nm) on expression of pro-inflammatory cytokines in murine immunocytes (splenocytes and peritoneal macrophages) in vitro. The LLLI on lipopolysaccharide (LPS 100 ng/ml)-stimulated murine splenocytes and macrophages, clearly down regulated mRNA expression of $TNF-{\alpha}$ and IL-12 in dose-dependent manner. In addition, LLLI significantly inhibits the NO production in the LPS-stimulated murine macrophages. This data suggests that LLLI (wavelength of 630 nm) may exert an anti-inflammatory action via modulation of pro-inflammatory cytokine and NO production pathway.

• Molecular & Cellular Toxicology
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• v.1 no.2
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• pp.106-110
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• 2005

N-ethyl-N-nitrosourea (ENU), which is a toxin and a carcinogen, as well as a mutagen, has a variety of effects on mice. ENU induces point mutation in male germ cell. Number of mutant animals are developed with ENU treatment. However, potentiality ot ENU as a carcinogen is not fully understood, even though, mutagenicity of ENU is broadly studied, In the present study, the gene expression profiling and histopathological investigation of ENU treated mouse's liver and brain were investigated. Also, the expression patterns of cancer related genes in ENU-treated mouse were analyzed.

• Molecular & Cellular Toxicology
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• v.1 no.2
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• pp.78-86
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• 2005

Dioxins, especially 2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin (TCDD or dioxin), are ubiquitous environmental contaminants. TCDD is known that it has toxic effects in animals and humans, including chloracne, immune, reproductive and developmental toxicities, carcinogenicity, wasting syndrome and death. TCDD induces a broad spectrum of biological responses, including disruption of normal hormone signaling pathways, reproductive and developmental defects, immunotoxicity, liver damage, wasting syndrome and cancer. Many researches showed that TCDD induces gene expression of transcriptional factors related cell proliferation, signal transduction, immune system and cell cycle arrest at molecular and cellular levels. These toxic actions of TCDD are usually mediated with AhR (receptor, resulted from cell culture, animal and clinical studies). cDNA microarray can be used as a highly sensitive and informative marker for toxicity. Additionally, microarray analysis of dioxin-toxicity is able to provide an opportunity for the development of candidate bridging biomarkers of dioxin-toxicity. Through microarray technology, it is possible to understand the therapeutic effects of agonists within the context of toxic effects, classify new chemicals as to their complete effects on biological systems, and identify environmental factors that may influence safety.

• Molecular & Cellular Toxicology
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• v.1 no.2
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• pp.87-91
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• 2005

Although 2D-PAGE has been widely used as the primary method for protein separation, difficulties in displaying proteins with an extreme values of isoelectric paint (pI), molecular size and hydrophobicity limit the technique. In addition, time consuming steps involving protein transfer and extraction from the gel-pieces can result in sample loss. Here, we describe a novel protein separation technique with capillary size-exclusion chromatography (CSEC) for rapid protein identification from human plasma. The method includes protein fractionation along with molecular size followed by in-solution tryptic digestion and peptide analysis through reversed phase liquid chromatography (RPLC) coupled to nanoflow electrospray-tandem mass spectrometry (ESI-MS/MS). Tryptic peptides are applied an a $100\;{\mu}m\;i.d.{\times}10mm$ length pre-column and then separated on a $75\;{\mu}m{\times}200mm$ analytical column at -100 nL/min flaw rate. Proteins were identified over the wide ranges of pI (3.7-12.3) when this technique was applied to the analysis of $1-2\;{\mu}L$ of human plasma. This gel-free system provides fast fractionation and may be considered a complementary technique to SDS-PAGE in proteomics.

• Molecular & Cellular Toxicology
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• v.1 no.2
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• pp.92-98
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• 2005

DNA microarray analysis of gene expression in toxicogenomics typically requires relatively large amounts of total RNA. This limits the use of DNA microarray when the sample available is small. To confront this limitation, different methods of linear RNA amplification that generate antisense RNA (aRNA) have been optimized for microarray use. The target preparation strategy using amplified RNA in DNA microarray protocol can be divided into direct-incorporation labeling which resulted in cDNA targets (Cy-dye labeled cDNA from aRNA) and indirect-labeling which resulted in cRNA targets (i.e. Cy-dye labeled aRNA), respectively. However, despite the common use of amplified targets (cDNA or cRNA) from aRNAs, no systemic assessment for the use of amplified targets and bias in terms of hybridization performance has been reported. In this investigation, we have compared the hybridization performance of cRNA targets with cDNA targets from aRNA on a 10 K cDNA microarrays. Under optimized hybridization conditions, we found that 43% of outliers from cDNA technique and 86% from the outlier genes were reproducibly detected by both targets hybridization onto cDNA microarray. This suggests that the cRNA labeling method may have a reduced capacity for detecting the differential gene expression when compared to the cDNA target preparation. However, further validation of this discordant result should be pursued to determine which techniques possesses better accuracy in identifying truly differential genes.