• 한국물환경학회지
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• 제20권1호
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• pp.48-54
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• 2004

Two methods, a Ceriodaphnia algal uptake suppression test (CAUST) and a new toxicity test based on temperature control (TTBTC) which are based on feeding behaviour and temperature control, respectively, were developed and compared for the adoption as the better methodology for short-term toxicity screening. As previously published by Lee et aI., (1997), the CAUST method is based on the feeding behaviour of C. dubia and requires as little as 1 hour of contact time between C. dubia neonates and toxicant. However, even though CAUST requires only 1 hour of contact time, this method still take many hours for the preparation and measurement. Before the test starts, neonate digestive tracts were cleared by feeding yeast to the daphnids, Neonates were then exposed to toxicant, followed by addition of Scenedesmus subspiatus into the bioassay vessels. Daphnids were examined under the bright-field microscope with the presence of algae (indicated by a green colored digestive tract) or the absence of algae. Uptake indicated no toxic effect, whereas, absence of uptake indicated toxic inhibition. Unlike CAUST, the newly developed method (TTBTC) is based on just temperature control for the toxicity test of C. dubia. Initially, neonates are exposed to toxicants while the temperature of water bath containing media increased to $35.5^{\circ}C$. After 1.25 hour of contact time, the number of the daphnids, either live (no toxic effect) or dead (toxic effect), is counted without the aid of any instrument. In both methods, median effective concentrations ($EC_{50}$ values) were computed based on the results over a range of dosed toxicant concentrations. It showed that TTBTC was as sensitive as the standard 48-hour acute bioassay and CAUST. TTBTC and CAUST were much more sensitive than the I-hour I.Q. test and 30-minute Microtox. This study indicates that TTBTC is an easier and more rapid toxicity test than the standard 48-hour acute bioassay and even CAUST.

• 대한본초학회지
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• 제21권1호
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• pp.101-107
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• 2006

Objectives : It is well known that hexavalent chromium has toxic effect on normal cells. Recently, toxic effect of hexavalent chromium is diminished by the some extracts derived from herbs or plants. But, the toxic or protective mechanism of hexavalent chromium is well unknown. This study was performed to examine the protective effect of poncirin against $Na_2Cr_2O_7$-induced cytotoxicity on NIH3T3 fibroblasts. Methods : The protective effect of the cytotoxicity induced by $Na_2Cr_2O_7$ was measured by the cell viability after NIH3T3 fibroblasts were cultured with or without $Na_2Cr_2O_7$ for 48 hours. Antitoxic effects of poncirin on the cytotoxicity induced by $Na_2Cr_2O_7$ were examined by colorimetric assays such as MTT or XTT assay. Results : $Na_2Cr_2O_7$ decreased cell viability by the decreased absorbance in MTT or XTT assay, but, the poncirin increased cell viability which was decreased by $Na_2Cr_2O_7$-induced cytotoxicity on NIH3T3 fibroblasts. Conclusion : These results suggest that $Na_2Cr_2O_7$ showed cytotoxicity effect on NIH3T3 fibroblasts by the decrease of cell viavility, and poncirin was effective in the protection of $Na_2Cr_2O_7$-induced cytotoxicity in these cultures.

• Toxicological Research
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• 제21권2호
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• pp.129-134
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• 2005

Styrene is a commercially important chemical used mainly in the production of plastics. A toxic effect exerted by styrene exposure may cause infertility, congenital anomalies or death in offspring. Treatment with styrene for 0, 50, 100, and 500 mg/kg for 5 days in Sprague-Dawley rats significantly decreased sperm motilities and sperm counts while sperm abnormalities were significantly increased. To determine the relationship between changes in sperm motilities and roles of reactive oxygen species (ROS), we determined the effect of styrene on ROS production and mRNA expression of antioxidant enzymes in rats. ROS production was enhanced by styrene treatment in a dose-dependent manner. The mRNA expression of catalase and superoxide dismutase (SOD) 2 was strongly suppressed by styrene treatment although SOD1 or glutathione peroxidase (GPX) 4 expressions were not significantly changed. Taken together, these results indicate that styrene may cause toxic effect in rat sperm cells by enhancing oxidative stresses.

• 환경위생공학
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• 제16권3호
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• pp.72-79
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• 2001

The selective catalytic oxidation of toxic aromatic solvents (benzene, toluene, ethylbenzene, and styrene) and their mixtures were studied on a $Pt/{\;}{\gamma}-Al_2O_3$ catalyst at temperature ranging from $160~350^{\circ}C$. The deep conversion of aromatic solvents was increased as the inlet concentration was decreased and the reaction temperature was increased. The reactivity increases in order benzene > toluene > ethylbenzene > styrene. In mixture, remarkable effects on reaction rate and selectivity have been evidence ; the strongest inhibition effect is shown by styrene and increase in a reverse order with respect to that of reactivity. The inhibition effect was increased in order styrene > ethylbenzene > toluzene > benzene. This trend is due to the competition adsorption between the two or three reactants on the oxidized catalyst. Also, the deep conversion change of benzene was a small in tertiary mixtures(including of benzene and styrene) comparing with conversion characteristics of binary mixture with styrene. This result was due to small concentration of styrene. which had very strong inhibition effect.

• 대한의생명과학회지
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• 제7권1호
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• pp.27-30
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• 2001

We have examined if lactic acid bacteria could suppress the toxic effect of bisphenol A. Lactobacillus casei YA-70 was chosen as representative. Thirty rats were divided into two groups (immature and mature) according to the weight. Each group was divided again into the control group (only alcohol treatment), bisphenol A treated group, and bisphenol A plus Lactobacillus casei YA-70 treated group. When 500 ppm of bisphenol A was fed everyday, 83% of immature group and 50% of mature group died within 3 weeks. Their internal organs, mainly livers and lungs, were changed in color and severely damaged. In the intestine of 5 ppm-fed group tumor-like nodules were observed. However, their number and size were markedly decreased when Lactobacillus casei YA-70 was supplemented in diet. This study strongly indicates that Lactobacillus casei YA-70 might play an important role to suppress the toxic effect of endocrine disruptor.

• 대한한의학회지
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• 제20권4호
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• pp.3-10
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• 2000

In order to elucidate the toxic mechanism of neurotoxical damage and neuroprotective effect of Jangwon-hwan(Zhuangyuan-wan) water extract, this experiment was performed. Neurotoxic effects of xanthine oxidase/hypoxanthine(XO/HX) were examined by MTT and NR assay, neuroprotective effects of Jangwon-hwan(Zhuangyuan-wan) water extract were examined by neurofilament enzymeimmuno assay(EIA). XO/HX induced an increase in cell viability, and a decrease in the amount of neurofilament on cultured mouse cerebral cortical neurons in dose-dependent manner. In neuroprotective effect of herb medicine, Jangwon-hwan(Zhuangyuan-wan) water extract increased the amount of neurofilament on cultured mouse cerebral cortical neurons damaged by XO/HX. From the results, it is suggested that XO/HX showed toxic effect in cultured mouse cerebral cortical Neurons and Jangwon-hwan(Zhuangyuan-wan) water extract is very effective in the prevention of neurotoxicity induced by XO/HX.

• Environmental Analysis Health and Toxicology
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• 제11권3_4호
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• pp.1-10
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• 1996

The purpose of this study was to characterise the subacute toxic potency of i.v. administered KHPC-005 and 006. Few test compounds-related toxic effects were observed in body weight gain, clinical signs, urinalysis, hematological parameters and serum biochemical values. Gross necropsy and histopathology revealed no evidance specific toxicity. Our data indicated that no-observed effect level of KI-IPC-005 and 006 were estimated to be 10mg/kg and 4mg/kg in male rats, and 10mg/kg and 1.33mg/kg in female rats, respectively.

• 약학회지
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• 제28권1호
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• pp.29-33
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• 1984

The paper aimed to review the influences of ginseng on the metabolism of foreign substances and on the activity of hepatic drug metabolizing enzyme system in mouse or rat liver. It has been known that ginseng components reduces the motality rates and the toxic effects induced by foreign materials. Chronic pretreatment of mouse or rat with ginseng extract fractions or saponin caused the increase in the metabolism of foreign materials and the activity of drug metabolizing enzymes, such as cytochrome $P_{450}$, NADPH cytochrome C reductase and glucuronyl S-transferase in liver. Thus, it may be concluded that decrease in toxic effect of foreign substances by ginseng pretreatment may be partly related to the induction of drug metabolizing enzymes in liver.

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1994년도 교수 연수회(환경)
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• pp.412-415
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• 1994

The fundamental assumption that thresholds exist for noncarcinogenic toxic effects of chemicals is reviewed; this assumption forms the basis for the no-observed-effect level/ safety-factor (NOEL/SF) approach to risk assessment for such effects. The origin and evolution of the NOEL/SF approach are traced, and its limitations are discussed. The recently proposed use of dose-response modeling to estimate a benchmark dose as a replacement for the NOEL is explained. The possibility of expanding dose-response modeling of non carcinogenic effects to include the estimation of assumed thresholds is discussed. A new method for conversion of quantitative toxic responses to a probability scale for risk assessment via dose-response modeling is outlined.

• 대한약리학회지
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• 제17권2호
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• pp.31-36
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• 1981

Heavy metals which are present as trace elements in human body have been known to modify various enzymatic reaction. These metals can be essential or non-essential. Zinc, copper and calcium are essential in maintaining some biological processes, whereas non-essential metals such as cadmium, lead and mercury produce accumulatve toxic effect. Cadmium accumulated in pancreas can cause toxicity and damage of pancreatic cells, thereby influencing CHO metabolism. Lead compounds are known to produce toxic effects on the kidney, digestive system and brain fellowed by inhibition of activity of ${\rho}-aminolevulinic$ acid and biosynthesis of hemoproteins and cytochrome. Evidence has been accumulated that zinc not only acts as a cofactor in enzyme reaction but also prevents toxic effect induced by heavy metal such as copper and cadmium. To demonstrate the effect of heavy metals on pancreatic secretion, part of uncinate pancreas was taken and incubated in Krebs-Ringer bicarbonate buffer with heavy metals used. Additional treatment with CCK-OP was performed when needed. After incubation during different period of time, medium was analyzed for amylase activity using Bernfeld's method. The present study was attempted in order to elucidate the effect of several kinds of heavy metal on exocrine pancreatic secretion in vitro. The results obtained are as follows: 1) CCK-OP stimulated significantly amylase release from pancreatic fragments in vitro. 2) CCK-OP response of amylase release from pancreatic fragments was inhibited by treatmant with cadmium, especially high doses of cadmium. 3) CCK-OP response of amylase release from pancreatic fragments was inhibited when pretreated with $10^{-4}M$ copper chloride. 4) Lead chloride at the concentration of $10^{-3}M\;and\;10^{4}M$ stimulated the basal amylase release in vitro but CCK-OP response did not augment by lead chloride. 5) Zine chloride did not affect amylase release from pancreatic fragment in vitro. From the results mentioned above, it is suggested that CCK-OP response was inhibited it the amylase release from pancreatic fragments pretreated with cadmium and copper chloride.