• Asian Pacific Journal of Cancer Prevention
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• v.16 no.16
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• pp.7143-7147
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• 2015

Gold nanoparticles (GNPs) were conjugated with gallic acid (GA) at various concentrations between 30 and $150{\mu}M$ and characterized using transmission electron microscopy (TEM) and UV-Vis spectroscopy (UV-VIS). The anticancer activities of the gallic acid-stabilized gold nanoparticles against well-differentiated (M213) and moderately differentiated (M214) adenocarcinomas were then determined using a neutral red assay. The GA mechanism of action was evaluated using Fourier transform infrared (FTIR) microspectroscopy. Distinctive features of the FTIR spectra between the control and GA-treated cells were confirmed by principal component analysis (PCA). The surface plasmon resonance spectra of the GNPs had a maximum absorption at 520 nm, whereas GNPs-GA shifted the maximum absorption values. In an in vitro study, the complexed GNPs-GA had an increased ability to inhibit the proliferation of cancer cells that was statistically significant (P<0.0001) in both M213 and M214 cells compared to GA alone, indicating that the anticancer activity of GA can be improved by conjugation with GNPs. Moreover, PCA revealed that exposure of the tested cells to GA resulted in significant changes in their cell membrane lipids and fatty acids, which may enhance the efficacy of this anticancer activity regarding apoptosis pathways.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.971-980
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• 2000

Mixed methanotrophs (MM) secreting soluble methane monooxygenase(sMMO) were immobilized on celite R-635 to degrade trichloroethylene(TCE) in methanotrophic consortium biofilm reactor(MCBR) system. Further neutralization of celite R-635 was not needed for immobilization because effluent pH was stabilized at neutral after 4 hour washing. It took 130 days to develop biofilm on celite R-635 and the color of the celite changed gradually from white to red. After biofilm developed, influent methane and oxygen were decreased from 2.5~4 and 8~10 ppm to 0.5~1 and 1~2 ppm, respectively, With influent 2 ppm of TCE and 10 hours of retention time, 79.9% of TCE was degraded in the MCBR system.

• Journal of the Korean Society of Tobacco Science
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• v.30 no.1
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• pp.14-24
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• 2008

The objective of this study was to determine the effect of smoking conditions on the in vitro toxicological activity of mainstream smoke. The 2R4F reference cigarette was machine-smoked by International Organization for Standardization(ISO) and Canadian Intense(CI) conditions. Smoke was analysed for chemical composition and in vitro toxicity. The cytotoxic potencies of both the total particulate matter(TPM), which were collected in Cambridge filter pad, and gas/vapor phase(GVP), which was bubbled through in phosphate-buffer saline in a gas-washing bottle, were assessed neutral red up take assay with chinese hamster ovary(CHO) cells. The assessment for genotoxicity of TPMs generated under ISO and CI conditions was determined using Salmonella mutagenicity assay and in vitro micronucleus assay. When calculated on an equal TPM basis, in vitro toxicity of TPM obtained under CI condition was decreased compared to TPM generated under ISO condition. The results of chemical composition analyses revealed that the lower toxicological activity under CI condition than that of ISO condition could be explained by the decreased in the contents of phenols, N-nitrosoamines and aromatic amines of TPM on an equal TPM basis.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.453-456
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• 2001

The purpose of this research was to investigate the effects of extracts from cultured hairy roots of R. undulatum on human kidney epithelial cells. Hairy roots were induced by a co-culture with A. rhizogenes ATCCl5834 and cultured in WPM medium. The cytotoxicity was measured by colorimetric assay using 3-(4,5-dimethythiazol-2-yl)-2,5- diphenyl-2H -tetrazolium bromide (MTT), neutral red (NR) and sulforhodamine protein B (SRB) with human kidney epithelial cell lines A498. MTT, NR and SRB quantities decreased propotionally in cultured A498 cells treated with the water or chloroform extracts of cultured hairy roots at increasing concentrations. These results suggest that extracts of cultured hairy 개ots are cytotoxic on human epithelial cells. The cytotoxicity of chloroforrm fraction was stronger than that of water fraction. The values of $MTT_{50}$, $NR_{50}$, $SRB_{50}$ of the extracts of chloroform fraction and those of water fraction were measured to be 289.3${\mu}g$/ml, 302.7${\mu}g$/ml. 433.8${\mu}g$/ml and 475.8${\mu}g$/ml. 428.3${\mu}g$/ml, 549.5${\mu}g$/ml in A498 cell line.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.97-97
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• 2003

Embryonic stem (ES) cells, derived from preimplantation embryos, are able to differentiate into various types of cells consisting the whole body, or pluripotency. In addition to the plasticity, ES cells are expected to be different from terminally differentiated cells in very many ways, such as patterns of gene expressions, ability and response of the cells in confronting environmental stimulations, metabolism, and growth rate. As a model system to differentiate these two types of cells, human ES (hES, MB03) cells and terminally differentiated cells (HeLa), we examined the ability of these two types of cells in confronting a severe oxidative insult, that is $H_2 O_2$. Ratio of dying cells as determined by the relative amount of dye neutral red entrapped within the cells after the exposures. Cell death rates were not significantly different when either MB03 or HeLa were exposed up to 0.4 mM $H_2 O_2$. However, relative amount of dye entrapped within the cells sharply decreased down to 0.12% in HeLa cells when the cells were exposed to 0.8 mM $H_2 O_2$, while it was approximately 54% in MB03. Pretreatment of cells with BSO (GSH chelator) and measurement of GSH content results suggest that cellular GSH is the major defensive mechanism of hES cells. Induction of apoptosis in hES cell was confirmed by DNA laddering, induction of Bax, and chromatin condensation. In summary, hES cells 1) are extremely resistant to oxidative stress, 2) utilize GSH as a major defensive mechanism. and 3) experience apoptosis upon exposure to oxidative stress.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.197-199
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• 2017

Using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI we study the ${3.3{\mu}m}$ polycyclic aromatic hydrocarbon (PAH) feature and its connection to active galactic nucleus (AGN) properties for a sample of 54 hard X-ray selected bright AGN, including both Seyfert 1 and Seyfert 2 type objects. The sample is selected from the 9-month Swift/BAT survey in the 14-195 keV band and all of the sources have known neutral hydrogen column densities ($N_H$). The ${3.3{\mu}m}$ PAH luminosity ($L_{3.3{\mu}m}$) is used as a proxy for star-formation (SF) activity and hard X-ray luminosity ($L_{14-195keV}$) as an indicator of the AGN power. We explore for possible difference of SF activity between type 1 (un-absorbed) and type 2 (absorbed) AGN. We use several statistical analyses taking the upper-limits of the PAH lines into account utilizing survival analysis methods. The results of our log($L_{14-195keV}$) versus log($L_{3.3{\mu}m}$) regression shows a positive correlation and the slope for the type 1/unobscured AGN is steeper than that of type 2/obscured AGN at a $3{\sigma}$ level. Also our analysis shows that the circum-nuclear SF is more enhanced in type 2/absorbed AGN than type 1/un-absorbed AGN for low $L_{14-195keV}$ luminosity/low Eddington ratio AGN, while there is no significant dependence of SF activity on the AGN type in the high $L_{14-195keV}$ luminosities/Eddington ratios.

• Toxicological Research
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• v.14 no.3
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• pp.315-320
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• 1998

In vitro skin iritation of anti-inflammatory drugs was investigated in terms of the cytotoxicity method to human skin fibroblast cells. Five anti-inflammatory drugs (Diclofenac, Naproxen, Meclofenamic acid, Ibuprofen and Fnoprofen) which are commercially available as oral preparations or injections were tested. The cytotoxicity of 5 chemicals was evaluated by using MTT[tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. NRU (neutral red uptake) assay and Alamar Blue assay after fibroblast cells had been exposed to the chemicals for 24 hours or 489 hours. The $IC_{50}$ values of the chemicals showed the comparative strength of cytotoxicity as following order of Meclofenamic acid>Diclofenac>Fenoprofen>Ibuprofen>Naproxen. The values of $IC_{50}$ determined by Alamar Blue assay were lower than those of MTT and NRU assay. These data suggest Alamar Blue assay can be useful method for assessing in vitro skin irritation potential of anti-inflammatory drugs.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.2
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• pp.343-347
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• 2002

In order to darify the neuroprotective effect of Gamibojungikki-tang(GBJIKT) water extract on cultured mouse spinal sensory neuron damaged by glucose Oxidase (GO), NR (Neutral Red) assay and LDH (Lactate Dehydrogenase) activity assay were carried out after the cultured mouse spinal sensory neuron were preincubated with various concentrations of GBJIKT water extract for 3 hours prior to exposure of GO. Cell viability of cultured mouse spinal sensory neurons exposed to various concentrations of GO for 8 hours was decreased in a dose-dependent manner. NR/sub 50/ values were 50 mU/ml GO. Cultured mouse spinal sensory neurons in the medium containing various concentration of GO for 8 hours showed increasing of LDH activity. We knew that GO was toxic on cultured spinal sensory neurons. Pretreatment of GBJIKT water extract for 3 hours following GO prevented the GO-induced neurotoxicity such as increasing of LDH activity. These results suggest that GO shows toxic effect on cultured spinal sensory neurons and GBJIKT water extract is highly effective in proecting the neurotoxicity induced by GO.

• Korean Journal of Pharmacognosy
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• v.25 no.3
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• pp.249-257
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• 1994

The cytotoxic and antitumor activity of Perilla frutescens extract on cultured 3T3 fibroblast and skin melanoma cells were evaluated by tetrazolium MTT (MTT) and neutral red (NR) colorimetric assay methods. Lactate dehydrogenase activity was also measured. The light microscopic study was carried out to observe morphological changes of cultured mouse fibroblast and skin melanoma cells. The results were as follows: 1. Water and ether extracts showed a significant cytotoxicity in 3T3 fibroblast and all extracts exhibited a significant anti-tumor activity in skin melanoma cells. Methanol, ethyl acetate and ethanol extracts showed low cytotoxic effects, but exhibited a high anti-tumor activity. 2. The MTT absorbance in 3T3 fibroblast was significantly decreased by treatment with ether, water, chloroform and ethanol extracts and skin melanoma cells was significantly decreased by treatment with all extracts. The difference in MTT absorbance in two cell types was most remarkable when treated with methanol and ethanol extracts. 3. Methanol and ethyl acetate extracts showed the strongest effect in growth inhibition of melanoma cells. These results indicated that methanol extract possessed a low cytotoxicity and a strong anti-tumor activity.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.403-424
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• 1996

Cell culture methods have been used to assess the cytotoxicity of dental materials. Different paramaters are used to monitor cytotoxic effects. But it is difficult to compare each investigator's results with different methods. The objective of this study was to investigate cytotoxic effect of several retrograde filling materials according to cell lines and assay methods. Cytotoxicity of Bestalloy (Dogmyung, Korea), Prisma APH(Densply International Inc., U.S.A.), Clearfil FII (Kuraray Co., Japan), Fuji II (GC Co., Japan), Fuji II LC (GC Co., Japan) and IRM (Densply Co., U.S.A.) on L929, 3T3 and KB permanent cell lines was measured. Radiochromium, Lactate dehydrogenase (LDH) release method and colorimetric assays, namely neutral red (NR) and MTT were used. Each material was mixed according to the manufacturer's instruction. They were tested as solid and extracted state. Cell culture media were added to each mixed or solid materials then the solution was collected and used as extract solutions. Solid Fuji II showed mild cytotoxicity on three cell lines using radiochromium release method. There was no difference in cytotoxicity of extract solution group using radiochromium release method. In colorimetric assay immediate Fuji II group and all the IRM groups showed severe cytotoxic effect. Difference in cyctotoxicity was due to rather kinds of cell lines than assay methods. Solid Fuji II and IRM showed mild cytotoxicity on three cell lines. But extract solutions had different cytotoxic effect according to cell lines using LDH release assay. Light-cured glass ionomer had mild to moderate degree of cytotoxicity on three cell lines. Cytotoxicity was affected by specimen prepaton. Susceptibility of each cell ines were also affected by assay emthods. It was suggested that cytotoxicity study using only one cell line and/or assay method might not accurately reflect the real toxic nature of dental biomaterials.