• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1310-1316
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• 2005

To evaluate the toxicological properties of human cytochrome P450 2E1 (CYP2E1) induced by ethanol and possible protective effects of various green tea catechins on alcohol-induced toxicity, transfected HepG2 cells that stably and constitutively express human CYP2E1 were established using the recombinant retroviral expression vector. Exposure of the CYP2E1-expressing HepG2 cells to high concentration of ethanol (200 mM) for 5 days resulted in a more than $50\%$ increase of cytotoxicity, assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction, lactate dehydrogenase (LDH) release, and reactive oxygen species (ROS) production, and loss of normal morphology, in comparison with HepG2 cells containing control vector. Treatment of the cells with various catechins increased cell viability by more than 2-fold. (-)-Epicatechin gallate and(-)-catechin gallate at the lowest concentration ($5\;{\mu}M$) attenuated cell death induced CYP2E1 by $60-65\%$. Therefore, the results showed that the catechins, including epimerized catechins, have strong protective effects against alcohol-induced CYP2E1 toxicity, and it is correlated with antioxidant effect.

• Environmental Analysis Health and Toxicology
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• 제22권2호통권57호
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• pp.137-145
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• 2007

The effect of cadmium chloride $(CdCl_2)$ on the expression of E-cadherin was examined in bEnd.3 mouse brain endothelial cells. $CdCl_2$ induced $PGE_2$ release, which were blocked by non-steroidal antinflamatory drugs (NSAIDs) such as indomethacin and NS398 indicating the expression of COX-2 might contribute to $PGE_2$ production. $CdCl_2$ decreased the expression of E-cadherin, but not VE-cadherin at levels of mRNA and protein. Reduced expression level of E-cadherin was restored by NSAIDs, which was reversed by the addition of $PGE_2$. $CdC_2$-induced decrease of E-cadherin level was also recovered by antioxidants including N-acetylcyteine (NAC) and trolox. Together with previous report which showed $CdCl_2$ induced COX-2 expression in a cellular oxidative stress dependent manner, these data suggest that $CdCl_2$ decreases E-cadherin expression through induction of cellular oxidative stress and in turn COX-2 expression in brain endothelial cells.

• Environmental Analysis Health and Toxicology
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• 제20권3호
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• pp.215-221
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• 2005

Environmental polycyclic aromatic hydrocarbones (PAHs), which are formed during incomplete combustion of fossil fuels, are widely distributed in our environment. Human exposure to PAHs may occur through smoking, polluted air, food consumption and occupational contact. Urinary naphthols, 1-and 2-naphthol, have been suggested as route -specific biomarkers for exposure to airborne PAHs. Cytochrome p450 2E1 (CYP2E1) is known to be a great importance for the metabolism of organic solvents, which is a precacinogens with small molecular weight. This study describes the metabolic differences between PstI and RsaI polymorphisms (c1 allele: PstI-. RsaI+ ; c2 allele: PstI+, RsaI-) of CYP2E1 5-flanking region by genetically modified HepG2 cells, which overexpress the polymorphic regions. The results of CAT assay and western blot in the c2 allele overexpressed cells have higher activities than the cl allele over-expressing cells. However, the metabolism of naphthalene to 2-naphthol has no difference due to the two genotypes. In this study, we established the CYP2E1 polymorphic allele transduced HepG2 cells to screen susceptibility -differences in PAH exposure. In conclusion, the CYP2E1 polymorphism may hardly induce susceptibility differences in PAH exposure monitoring with urinary naphthols.

• 한국동물위생학회지
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• 제44권4호
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• pp.209-216
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• 2021

This study was aimed to investigate occurrence and the antimicrobial resistance of Escherichia coli isolates obtained from the feces of wild birds in Daegu. In total, 98 E. coli isolates (17.9%) were obtained from 547 fecal samples of wild birds. The E. coli carried by the birds showed a relatively high rate of antimicrobial resistance to tetracycline (27.6%) and ampicillin (21.4%). Drug resistance of the isolates to the others (penicillins, cephems, carbapenems, aminoglycosides, quinolones, sulfonamides and phenicols) resulted in the rates less than 20%, and all isolates were susceptible to imipenem, ciprofloxacin, cefotetan, and amikacin. Approximately, 45% E. coli among the isolates were resistant to one or more drugs tested. The higher rate of tetracycline resistance led us to determine the prevalence of the tet genes (tetA, tetB, tetC, tetD and tetE) in the tetracycline-resistant E. coli isolates by using PCR. All isolates of the tetracycline-resistant E. coli contained at least one or more of these tet genes examined. The most prevalent one was tetA (59.3%), and followed by tetB (7.4%) when tested with the selected 5 tet genes. Except tetA and tetB, however, the remaining tet genes (tetC, tetD, and tetE) tested were not found in this study. Nine isolates among the tetracycline-resistant E. coli contained the two (tetA and tetB) determinants of tetracycline resistance, simultaneously.

• 미생물학회지
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• 제34권1_2호
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• pp.20-25
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• 1998

PCBs를 분해하는 Pseudomonas sp. P20 균주의 pcbC gene이 재조합 된 E. coli CK1092 균주를 이용하여 2,3-dihydroxybiphenyl dioxygenase 생산에 미치는 배양조건을 검토하였다. E. coli CK1092를 2% sucrose가 포함된 LB 배지를 기본배지로 하여 질소원, 금속이온 등의 영향을 조사한 결과, $Fe^{3+}$와 $Fe^{2+}$이 $10^{-5}M$의 농도일때 효소생산이 증가되었으며 배양최적온도는 $37^{\circ}C$, 배양초기 pH 7.0일때 효소생산이 우수하였다. 배양조에서의 배양조건은 초기 pH 7.0, 통기량 1 v/v/m, 교반속도 200rpm에서 가장 효소생성이 우수하였다.

• 한국수의병리학회:학술대회논문집
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• 한국수의병리학회 2002년도 추계학술대회초록집
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• pp.146-146
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• 2002

Hepatic disease has been noted and reported for involvement various detrimental factors. Among many detrimental injury factors, alcohol has been noted for hepatitis, fatty liver, fibrosis, and hepatic cirrhosis. The purpose of this study is to develop animal model for hepatic fibrosis in pig with ethanol, and to search new anti-fibrogenic agent. Twelve male Landrace pigs were divided into 3 groups of 4 animals each. Group 1, 2 and 3 were fed with ceramic water only, ceramic water + liquid diet containing 20％ ethanol and normal tap water + containing 20％ ethanol for 12 weeks, respectively. At week 12, all pigs were immediately sacrificed for collection each tissue and blood. Serologically, serum ALT and AST levels were significantly reversed in group 2, comparing to group 3. They were normal range in pigs of group 1. Microscopically, macrovesicular lipid droplets and moderate necrosis were evident in the tap water + ethanol fed group 3. However, ceramic water intake group 1 showed normal. Moreover, in group 3, little fatty changes and mild necrosis were observed. Collagen fibers were detected in the spaces of surrounding periportal and interlobular areas in the group 3 of tap water + ethanol, but collagen synthesis and its thickness of fibrotic septa connecting portal tracts was markedly reduced in the group 2 of ceramic water + ethanol. In immunohistochemistry, myofibroblasts were detected in the ethanol and tap water treated group 3. No or a few myofibroblasts were observed in groups 1 and 2. CYP 2E1 was rarely detected in group 1 fed ceramic water. However, group 2 showed slightly activation of CYP 2E1 in the area of pericentral, while CYP 2E1 was significantly activated in group 3 fed tap and ethanol. Taken together above, alcohol fibrosis model in pig was established. Furthermore, ceramic water had an inhibitory and protecting ability for alcohol-induced hepatic damages.

• 지구물리와물리탐사
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• 제13권2호
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• pp.137-143
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• 2010

2000년 12월 9일 경북 영덕 해역에서 국지규모$(M_L)$ 3.7의 지진이 발생하였다. Chang and Baag (2006) 지각속도구조 모델을 적용할 경우 진앙의 위치는 $36.4462^{\circ}N,\;129.9789^{\circ}E$이며, 지체구조구상 한반도 대륙붕에 해당한다. 동해에서 대륙지각이 해양지각으로 변이되는 점을 고려하여 지각의 두께를 5 km 얇게 조정한 모델을 사용해도 진앙 위치의 변화는 거의 없었다. 파형역산을 두 모델에 적용하여 지진의 깊이와 발진기구를 계산하였다. 영덕 해역 지진의 깊이는11 ~ 12 km로 계산되었다. 지진모멘트는 $1.0{\times}10^{15}N{\cdot}m$로 추정되었는데, 이 값은 모멘트규모$(M_W)$ 3.9에 해당한다. 영덕해역 지진은 2004년 5월 29일에 발생한 울진 해역 지진과 함께 전형적인 역단층 특성을 보여주며, P축의 방향은 동남동-서북서 방향이다. 스펙트럼 분석을 통해 추정된 모멘트규모는 4.0이며, 이는 파형역산에 의해 추정된 모멘트규모와 거의 비슷하다. 평균 응력강하는 3.4 MPa로 추정되었다.

• IMMUNE NETWORK
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• 제23권1호
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• pp.3.1-3.14
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• 2023

Microvilli are outer membrane organelles that contain cross-linked filamentous actin. Unlike well-characterized epithelial microvilli, T-cell microvilli are dynamic similar to those of filopodia, which grow and shrink intermittently via the alternate actin-assembly and -disassembly. T-cell microvilli are specialized for sensing Ags on the surface of Ag-presenting cells (APCs). Thus, these finger-shaped microprotrusions contain many signaling-related proteins and can serve as a signaling platforms that induce intracellular signals. However, they are not limited to sensing external information but can provide sites for parts of the cell-body to tear away from the cell. Cells are known to produce many types of extracellular vesicles (EVs), such as exosomes, microvesicles, and membrane particles. T cells also produce EVs, but little is known about under what conditions T cells generate EVs and which types of EVs are released. We discovered that T cells produce few exosomes but release large amounsts of microvilli-derived particles during physical interaction with APCs. Although much is unanswered as to why T cells use the same organelles to sense Ags or to produce EVs, these events can significantly affect T cell fate, including clonal expansion and death. Since TCRs are localized at microvilli tips, this membrane event also raises a new question regarding long-standing paradigm in T cell biology; i.e., surface TCR downmodulation following T cell activation. Since T-cell microvilli particles carry T-cell message to their cognate partner, these particles are termed T-cell immunological synaptosomes (TISs). We discuss the potential physiological role of TISs and their application to immunotherapies.

• 치과방사선
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• 제27권1호
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• pp.55-71
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• 1997

Digora/sup (R)/ an intraoral digital radiography system utilizing image plate (IP) - has a dynamic range of exposure time which allows it to decrease the patient's exposure time and to increase diagnostic ability through image processing, transmission and storage. The purpose of this study was to evaluate the Digora/sup (R)/ system by assessing the effects of various exposure times on the detectability on the tip of the endodontic file. Examining the root canals of 45 extracted sound premolars, K -files No. 10, 15, and 20 were placed at slightly varying distances from the apex. The teeth were glued onto resin-plaster blocks. Five exposure times varying between 0.01 seconds and 0.25 seconds were used. Four observers were asked to measure the distance between the tip of the file and a reduction of crown portion, and obtained mean errors (subtracting true file length from the measured file length), comparing Digora/sup (R)/ monitors with E-plus films, which were both obtained under the same geometrical positions. The results were as follows : 1. Comparing E-plus film with Digora/sup (R)/ at 0.01 seconds, the mean errors in E-plus film showed -4.453 nun, -4.497 nun, and -3.857 nun, while the mean errors in Digora/sup (R)/ showed 0.065 nun, 0.607 nun, and 0.719 mm according to the file groups. Therefore there was a significant difference between E-plus film and Digora/sup (R)/(p<0.05). 2. By comparison of mean errors according to the various exposure times in the Digora/sup (R)/ system, the mean error at 0.01 seconds was significantly lower than that at 0.12 and 0.25 seconds in the No. 10 file group(p<0.05). And the standard deviation was the highest at 0.01 seconds. 3. Comparing E-plus film at 0.25 seconds with the Digora/sup (R)/ system, the mean errors showed a significant difference between E-plus film at 0.25 seconds and the Digora/sup (R)/ system at 0.25 seconds in No. 10 and 20 file groups(p<0.05). 4. Comparing E -plus film at 0.25 seconds with other exposure times, the mean errors showed a significant difference between E-plus film at 0.25 seconds and E-plus film at 0 .. 01 and 0.03 seconds in 10 file group(p<0.05). In the No. 15 and 20 file groups, there was a significant difference between E-plus film at 0.25 seconds and E-plus film at 0.01 seconds(p<0.05). In conclusion, Digora/sup (R)/ was better than E-plus film in detectability on the tip of the file at the exposure time of 0.01 seconds in all file groups. And we concluded that Digora/sup (R)/ can shorten exposure times up to 4％ of 0.25 seconds (0.01 sec), which is adequate exposure time for premolar in E-plus film using No. 15 and 20 files.

• 조명전기설비학회논문지
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• 제23권9호
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• pp.1-5
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• 2009

수처리 살균에 이용되는 자외선 소독은 기존 염소소독법의 문제점인 소독부산물 생성이 없어 실질적인 대안으로 널리 수행되고 있다. 본 연구에서는 368.6[nm] 자외선을 이용하여 소독에 대해 저항성이 강한 대장균(E.coli)의 분활성화 특성을 파악하고자 하였다. 실험에 사용한 자외선 소독 장비는 358.6[nm]의 파장을 방사하는 자외선 램프를 사용하여 제작하였으며 소독 반응조에서 시간에 따른 사멸 특성을 살펴보았다 자외선으로 60분간 대장균을 조사하였을 때 초기 30분간은 자외선에 큰 영향을 밭지 않았지만 30분 이후에 대장균이 점차적으로 사멸되어 60분이 경과하였을 때 83.3[%]의 사멸률을 보여서 일반적인 자외선 램프보다 살균효율이 미약한 것을 확인할 수 있었다. 또한 동력학적 접근방법으로 구한 비활성화율 계수 k값은 0.00868[$cm^2$]/([$mW{\cdot}s$])로 나타났다.