• Environmental Analysis Health and Toxicology
• /
• v.29
• /
• pp.9.1-9.3
• /
• 2014

Diesel exhaust particles (DEP) contain elemental carbon, organic compounds including Polyaromatic hydrocarbons (PAHs), metals, and other trace compounds. Diesel exhaust is complex mixture of thousands of chemicals. Over forty air contaminants are recognized as toxicants, such as carcinogens. Most diesel exhaust particles have aerodynamic diameters falling within a range of 0.1 to $0.25{\mu}m$. DEP was classified as a definite human carcinogen (group 1) by the International Agency for Research on Cancer at 2012 based on recently sufficient epidemiological evidence for lung cancer. Significant decreases in DEP and other diesel exhaust constituents will not be evident immediately, and outworn diesel car having longer mileage still threatens health of people in spite of recent remarkable development in diesel engine technology. Policy change in South Korea, such as introduction of diesel taxi, may raise health risk of air pollution in metropolitan area with these limitations of diesel engine. To protect people against DEP in South Korea, progressive strategies are needed, including disallowance of diesel taxi, more strict regulation of diesel engine emission, obligatory diesel particulate filter attachment in outworn diesel car, and close monitoring about health effects of DEP.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2000.04a
• /
• pp.108-113
• /
• 2000

Freshwater borne bacteria transformed with luxAB-containing plasmid were optimized for the toxicity tests of various organic carbons and heavy metals. The EC$\sub$50/ values obtained from tests using the most sensitive bacterium to toxicants, YH9-RC, revealed to be much less than those from the Microtox$\^$/. In addition, some physiological characteristics of this bacterium under the toxic stress conditions such as potential bioluminescence, specific growth rate, and intracellular ATP contents, reproducibly and reliably correlated to the toxicity of the chemicals exposed. The higher concentrations of COD in wastewater samples, the lower EC$\sub$50/ values, therefore the developed toxicity test was found to be easily applicable to the toxicity test for wastewater samples and effluents. The conditions for constructing 384-multiwell plate containing freeze-dried bacterium were also optimized through the addition of 0.16 M trehalose before freeze-drying. Consequently, the advanced test system featuring a continuous measurement of the toxicity, an automated real-time monitoring of its results, and an alerting function was designed and constructed in combination with the microbiological, mechanical, and electronic compartment.

• Journal of Environmental Science International
• /
• v.24 no.11
• /
• pp.1541-1546
• /
• 2015

The objective of this research was to evaluate the toxicity of the industial xenobiotic Aroclor 1248 (A) and natural origin substances~elemental sulfur (S80) and oleic acid (OA) and their binary mixtures to V. fischeri bioluminescence during the prolonged exposure time (up to 60 min). The bioluminescence quenching test was used to determine the toxic effects. Full factorial experiment design and multiple regression analysis and the comparison of binary mixture effect with the sum of effects of individual chemicals were used for the evaluation of combined effects of toxicants. The analysis of general trend of mixture toxicity to bioluminescence showed that mixture toxic effects were reversible up to 60 min. Data analysis revealed different joint effects, which were depended on mixture composition. S80 enhanced toxic effect of A and acted additively with synergistic interaction. Hydrophobic OA in mixture with A acted antagonistically and in mixture with sulfur caused an additive effect with antagonistic component of interaction. It was concluded that low concentrations of natural toxic substances present in environmental samples as mixtures of chemicals can define the toxicodynamic character of industrial xenobiotics.

• Journal of Environmental Health Sciences
• /
• v.29 no.3
• /
• pp.9-15
• /
• 2003

The modification of CYP2El activity is a matter of considerable interest because of its role in the metabolic activation of a variety of environmental toxicants. In the present study, the time-course of changes in human CYP2El activities was determined following treatment with solvents (acetone, dimethylsulphoxide or pyridine) using intact HepG2 cells transfected by human CYP2El. Hydroxylation of chlorzoxazone was used for the measurement of CYP2El activity. CYP2E1 protein level was increased upon cultivation of cells in the presence of the solvents for 24 hr. Determination of CYP2El activities after 24 ht cultivation with the solvents demonstrated that acetone or dimethylsulphoxide increased, whereas pyridine inhibited the activities. This differential effect of the solvents on CYP2El activities persisted to subsequent 24 ht. Competitive inhibition study suggested that pyridine has stronger binding affinity to CYP2E1 than acetone or dimethylsulphoxide. These results demonstrate that different binding affinity of the solvents to CYP2El plays important role in determining real CYP2El activity in intact cells after exposure to the solvents. Present study would be helpful in precise understanding of human CYP2El-mediated toxicity.

• Toxicological Research
• /
• v.21 no.4
• /
• pp.271-278
• /
• 2005

Reproductive and developmental toxicology is concerned with various physical or chemical agents interfering with fertility in both gender or normal growth of offsprings. Reproductive and developmental toxicology is rather a complex science, with many fields, i.e., various endpoints are involved and many different mechanisms of action. For that reason, diverse aspects must be considered when attempting to assess possible adverse health effects in the area of reproductive and developmental toxicology. The thalidomide tragedy made it clear to regulatory authorities around the world that systematic, comprehensive evaluation of the reproductive cycle was needed to adequately evaluate the potential of medicinal drugs to impair the process of reproduction or the development of embryos, fetuses, and children. International Conference on Harmonization of Technical Requirements for the Registration of Pharmaceuticals for Human Use (ICH) and U.S. Food and Drug Administration (FDA) developed a guideline to assess the reproductive and developmental toxicity. Also these guidelines have since been applied to the detection and regulation of environmental toxicants, food additives, and so on. Although it was hoped that testing procedures of guideline would be updated constantly to reflect the current state of the science in reproductive and developmental toxicology, it was not until this decade that regulatory guidelines and testing methods have been altered in a significant way. In this paper, we would like to present the recommended approaches and recent trends for improvement of testing guidelines or experimental methods in reproductive and developmental toxicology.

• Biomolecules & Therapeutics
• /
• v.25 no.4
• /
• pp.367-373
• /
• 2017

This study was performed to evaluate whether microRNAs (miRNAs) in circulating exosomes may serve as biomarkers of drug-induced liver, kidney, or muscle-injury. Quantitative PCR analyses were performed to measure the amounts of liver-specific miRNAs (miR-122, miR-192, and miR-155), kidney-specific miR-146a, or muscle-specific miR-206 in plasma and exosomes from mice treated with liver, kidney or muscle toxicants. The levels of liver-specific miRNAs in circulating plasma and exosomes were elevated in acetaminophen-induced liver injury and returned to basal levels by treatment with antioxidant N-acetyl-cysteine. Circulating miR-146a and miR-206 were increased in cisplatin-induced nephrotoxicity and bupivacaine-induced myotoxicity, respectively. Taken together, these results indicate that circulating plasma and exosomal miRNAs can be used as potential biomarkers specific for drug-induced liver, kidney or muscle injury.

• Biomolecules & Therapeutics
• /
• v.1 no.1
• /
• pp.50-57
• /
• 1993

This study characterized the effect of liver injury produced by hepatotoxicants on the biliary and urinary excretion of acetaminophen(AA) metabolites. Liver damage was produced in male S.-D. rats, 24 hr after dosing with carbon tetrachloride(4CCl_4,$ 0.75 mι/kg, ip) or thioacetamide(TA, 200 mg/kg, ip), or 16 hr after administration of cadmium chloride(4CdCl_2,$ 3.9 mg/kg, iv). Liver damage without renal injury was confirmed by measuring serum enzymes, creatinine and BUN levels as well as by histopathological examination. AA and its metabolites were measured for 3 hr by HPLC in rats injected iv with 1 mmo1/kg of AA. The excreted amounts of AA-glucuronide into bile were reduced to 60~70% of control rats by hepatotoxicants, but did not change urinary excretion of AA-glucuronide and AA-sulfate. Treatments with $CCl_4,\; CdCl_2$ and TA decreased the total (biliary plus urinary) excretion of thioethers of AA(30~50% of control), suggesting that these toxicants decrease cytochrome P-450-mediated toxification of AA. However, treatments of $CdCl_2$and TA markedly enhanced the excretion of AA-mercapturate into urine. Thus, 4CdCl_2$ and TA not only influence the formation of AA-glutathione, but may also alter the excretory routes (i.e. bile and urine) for the elimination of AA-metabolite.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.2 no.2
• /
• pp.141-146
• /
• 1997

A new sensing system based on the immobilization of luminescent batcteria, Photobacterium phosphoreum, was proposed for continuous real-time monitoring of polluants. The response curves demonstrate that Photobacterium phosphoreum immobilized on the strontium alginate was very sensitive to seven reference chemicals used. The significant inhibitory concentrations for bioluminescence emission were 5 ppm for Pb(NO3)2, NiCl2, CdCl2, 50 ppm for NaAsO2, 0.1ppm for HgCl2, 0.5ppm for pentachlorophenol and less than 5ppm for SDS, respectively. The alginate mixed-cells (AMC) retained their luminescence during experimental period (29 days) under storage condition of -8$0^{\circ}C$. The variables affecting performance of continuous flow through monitoring (CFTM) were optimized in order to ensure stability and efficiency. The flow through cell with strontium-alginate immobilized luminescent bacteria was tested with salicylate and 4-nitrophenol and a rapid response of luminescence was recorded by time drive mode in bioluminescence spectrometer after exposure to both toxicants.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.22 no.5
• /
• pp.1293-1298
• /
• 2008

The purpose of this study is to investigate the effect of a mixture of fermented Artemisiae Argi Folium and fermented Sophorae Radix (FAS) on hydrogen peroxide production within mouse macrophage Raw 264.7 with ethanol (EtOH) and nicotine. Artemisiae Argi Folium is known to have the antibacterial, immune-enhancing properties. And Sophorae Radix is also known to have the antibacterial, anti-inflammatory, anti-allergic properties. EtOH and nicotine are the ones of toxicants which could impair immunocytes like macrophage. EtOH and nicotine reduce the intracellular production of hydrogen peroxide ($H_2O_2$) of Raw 264.7. FAS increased the production of hydrogen peroxide reduced by EtOH and nicotine within Raw 264.7. These results indicate that FAS could restore the immuno-activity of macrophage impaired by EtOH and nicotine.

• Toxicological Research
• /
• v.13 no.4
• /
• pp.385-391
• /
• 1997

Inductive effects of cytochrome P450 2B1 by $\alpha$- and $\beta$-ionone were characterized in individual liver lobes of male Sprague Dawley rats. When rats were administered ionones orally at 100, 300, and 600 mg/kg for 24 hr, cytochrome P450 2B1 was induced dose-dependently in liver S-9 fractions as measured by P450 2B-specific monooxygenases and Western immunoblotting. The activity of P450 1A- and P450 2B-specific monooxygenases was differentially expressed in each lobe of normal liver. In addition, the monooxygenase activity was induced by $\alpha$- and $\beta$-ionone with different potency in each lobe of the liver. Our present results indicate that the different induction of P450s by $\alpha$- and $\beta$-ionone in each lobe may explain different susceptibilities of rat liver lobes to certain hepatotoxicants which require metabolic activation for their toxicity and that $\alpha$- and $\beta$-ionone may be useful model inducers of P450 2B1 in studying the toxic mechanism of certain toxicants which may require the metabolic activation by P450.