Protective Effects of Houttuynia cordata Thunb. on Gentamicin-induced Oxidative Stress and Nephrotoxicity in Rats

Changgeun Kang,Hyungkyoung Lee,Do-Yun Hah,Jung Ho Heo,Chung Hui Kim,Euikyung Kim,Jong Shu Kim 한국독성학회 2013 Toxicological Research Vol.29 No.1

Development of a therapy providing protection from, or reversing gentamicin-sulfate (GS)-induced oxidative stress and nephrotoxicity would be of great clinical significance. The present study was designed to investigate the protective effects of Houttuynia cordata Thunb. (HC) against gentamicin sulfate-induced renal damage in rats. Twenty-eight Sprague-Dawley rats were divided into 4 equal groups as follows: group 1, control; group 2, GS 100 mg/kg/d, intraperitoneal (i.p.) injection; group 3, GS 100 mg/kg/d, i.p. + HC 500 mg/kg/d, oral; and group 4, GS 100 mg/kg/d i.p. + HC 1000 mg/kg/d, oral administration). Treatments were administered once daily for 12 d. After 12 d, biochemical and histopathological analyses were conducted to evaluate oxidative stress and renal nephrotoxicity. Serum levels of creatinine, malondialdehyde (MDA), and blood urea nitrogen (BUN), together with renal levels of MDA, glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) were quantified to evaluate antioxidant activity. Animals treated with GS alone showed a significant increase in serum levels of creatinine, BUN, and MDA, with decreased renal levels of GSH, SOD, and CAT. Treatment of rats with HC showed significant improvement in renal function, presumably as a result of decreased biochemical indices and oxidative stress parameters associated with GS-induced nephrotoxicity. Histopathological examination of the rat kidneys confirmed these observations. Therefore, the novel natural antioxidant HC may protect against GSinduced nephrotoxicity and oxidative stress in rats.

Advocacy Coalition Framework: The Mediation Effect of Coalition Opportunity Structures on the Relationship between External Shocks and Policy Change

( Changgeun Yun ) 한국정책학회 2016 한국정책학회 추계학술발표논문집 Vol.2016 No.-

The Advocacy Coalition Framework (ACF) is a theoretical framework for studies of policy change. Since its introduction in the late 1980s, it has undergone three revisions in 1993, 1998. and 2007. the 2007 revision has contributed to expanding the applicability of the ACF to policy processes in both pluralistic and non-pluralistic political systems by creaing a new category of variables: coalition opportunity strueture. However very little research has been conducted to examine whether and how opportunity structures affect the oplicy porocess. This study examines whether, to what extent, and in what ways extemal shocks cause oplicy change in different coalition opportunity structures. To do this, I investigage the effects of three global nuclear accidents on Korea`s nuclear energy oplicy. The findings suggest that coalition opportunity structures mediate the effect of an external shock on the oplicy opocess. In an authoritarian structure, a policy subsystem is monopolized, so external shocks cannot lead to policy change but instead are exploited by a dominant coalition to further strengthen ist opwer in the oplicy process. In a pluralistic structure, external shocks bring policy change as the ACF predicts because they serve as an opprotunity for minority coalitions to challenge a dominant one. the relationship between an external shock and policy change is not a simple stimulus-response reaction.

Evaluation of Oxidative DNA Damage Using an Alkaline Single Cell Gel Electrophoresis (SCGE) Comet Assay, and the Protective Effects of N-Acetylcysteine Amide on Zearalenone-induced Cytotoxicity in Chang Liver Cells

Changgeun Kang,Hyungkyoung Lee,Yong-San Yoo,Do-Yun Hah,Chung Hui Kim,Euikyung Kim,Jong Shu Kim 한국독성학회 2013 Toxicological Research Vol.29 No.1

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 μM) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 μM). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

Getting Better or Staying the Same? An Exploratory Study of the Recognition of Informatization by Residents

Changgeun Yun(尹昶根),Hyun-jae Choi(崔絢載),Cheol Hyun Jeong(鄭喆鉉) 한국지역정보화학회 2017 한국지역정보화학회지 Vol.20 No.1

정보화마을은 지난2001년부터 지역경제를 활성화하고 마을 및 주민간 지역공동체를 형성할 뿐만 아니라 주민의 편익향상을 목적으로 추진되었다. 그러나 정보기술의 변화가 급속히 이루어짐에 따라 정보화마을도 새로운 변화를 수용 및 대응하고, 새로운 체제를 모색해야 할 시점에 이르고 있다. 본 논문은 정보화마을 주민의 정보화 능력 및 정보화 인식을 조사하여 정보화마을 정책 발전을 위한 기초자료를 제공하는 데 있다. 정보화마을에 관한 인식을 파악할 뿐만 아니라 인식의 차이를 비교함으로써 미래 정보화마을 정책의 성공을 위한 함의를 도출할 수 있기 때문이다. 본 논문에서 도출된 정책적 함의는 다음과 같다. 첫째, 정보인프라는 잘 구축되어 있으나 정보인프라에 대한 접근과 관련하여 주민간 격차가 존재하고 있다. 둘째, 정보의 활용이 미흡하다. 셋째, 농어촌 지역의 정보화마을이 도시 지역의 정보화마을보다 운영과 활용이 덜 활성화되어 있다. 따라서 농어촌 지역의 정보화마을의 역량과 활용도를 향상시킬 필요가 있다. As information technology (IT) changes rapidly, INVs need to follow and make use of new technologies. To do this, it is essential to identify and analyze the effects of an INV, specifically (1) the ability of residents in an INV to access and use information and (2) their recognition of an INV. The purpose of this study is to determine the current status of INV policy by investigating the information ability level of residents and their recognition of informatization. We find that there is a broad variation in the ability to use Information Technology (IT) and to access to the Internet, implying that future policy should contribute to reducing the difference in recognition about INVs (i.e., using IT, utilizing information from the Internet, and digital divide) by gender (male vs. female) and regions (urban vs. rural).

모폴로지와 비선형 확산을 이용한 영상 분할

김창근(Changgeun Kim),유재명(Jaemyeong Yoo),이귀상(Gueesang Lee) 한국정보과학회 2004 한국정보과학회 학술발표논문집 Vol.31 No.2Ⅱ

영상을 유사한 특성을 갖는 영역 단위로 분할하는 작업은 다양한 영상 처리를 위한 전처리 과정으로 사용되고 있다. 본 논문에서는 모폴로지(morphology)와 비선형 확산(Non-Linear Diffusion)을 이용한 영상 분할 방법을 제안한다. 초기에 LUV 색상공간에 모폴로지를 응용한 재구성 (Reconstruction)에 의한 닫힘(Closing) 연산과 비선형 확산(Non-Linear Diffusion)을 통해 실험 영상을 획득한다. 이 영상에서 칼라 영상의 기울기(Gradient) 정보를 획득하고 마커(Marker) 정보를 이용한 워터쉐드(Watershed) 알고리즘을 적용하여 영상을 효과적으로 분할한다. 그레이 영상과 칼라 영상을 대상으로 한 실험에서 제안 방법이 영상을 효과적으로 분할함을 확인 하였다.

Protective Effects of Houttuynia cordata Thunb. on Gentamicin-induced Oxidative Stress and Nephrotoxicity in Rats

Kang, Changgeun,Lee, Hyungkyoung,Hah, Do-Yun,Heo, Jung Ho,Kim, Chung Hui,Kim, Euikyung,Kim, Jong Shu Korean Society of ToxicologyKorea Environmental Mu 2013 Toxicological Research Vol.29 No.1

Development of a therapy providing protection from, or reversing gentamicin-sulfate (GS)-induced oxidative stress and nephrotoxicity would be of great clinical significance. The present study was designed to investigate the protective effects of Houttuynia cordata Thunb. (HC) against gentamicin sulfate-induced renal damage in rats. Twenty-eight Sprague-Dawley rats were divided into 4 equal groups as follows: group 1, control; group 2, GS 100 mg/kg/d, intraperitoneal (i.p.) injection; group 3, GS 100 mg/kg/d, i.p. + HC 500 mg/kg/d, oral; and group 4, GS 100 mg/kg/d i.p. + HC 1000 mg/kg/d, oral administration). Treatments were administered once daily for 12 d. After 12 d, biochemical and histopathological analyses were conducted to evaluate oxidative stress and renal nephrotoxicity. Serum levels of creatinine, malondialdehyde (MDA), and blood urea nitrogen (BUN), together with renal levels of MDA, glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) were quantified to evaluate antioxidant activity. Animals treated with GS alone showed a significant increase in serum levels of creatinine, BUN, and MDA, with decreased renal levels of GSH, SOD, and CAT. Treatment of rats with HC showed significant improvement in renal function, presumably as a result of decreased biochemical indices and oxidative stress parameters associated with GS-induced nephrotoxicity. Histopathological examination of the rat kidneys confirmed these observations. Therefore, the novel natural antioxidant HC may protect against GSinduced nephrotoxicity and oxidative stress in rats.

Evaluation of Oxidative DNA Damage Using an Alkaline Single Cell Gel Electrophoresis (SCGE) Comet Assay, and the Protective Effects of N-Acetylcysteine Amide on Zearalenone-induced Cytotoxicity in Chang Liver Cells

Kang, Changgeun,Lee, Hyungkyoung,Yoo, Yong-San,Hah, Do-Yun,Kim, Chung Hui,Kim, Euikyung,Kim, Jong Shu Korean Society of ToxicologyKorea Environmental Mu 2013 Toxicological Research Vol.29 No.1

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 ${\mu}M$) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 ${\mu}M$). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

시간 정보와 공간 정보를 이용한 객체 추출

김창근(Changgeun Kim),유재명(Jaemyeong Yoo),이귀상(Gueesang Lee) 한국정보과학회 2004 한국정보과학회 학술발표논문집 Vol.31 No.1B

동영상에서 객체의 추출은 객체 단위로 압축하는 MPEG-4와 객체의 특성을 기술하고 유사한 영상을 검색하는 기능을 가진 MPEG-7에 기반 기술로, 동영상의 효과적인 압축 및 색인, 검색에 유용하게 사용되는 방법이다. 본 논문에서는 시간적 정보와 공간적 정보를 이용한 영상 분할 방법을 제시한다. 동영상은 배경 화면과 전방 객체로 이루어져 있는데, 여기서 프레임간 모션벡터로 글로벌영상(배경영상)의 움직임을 분리할 수 있다. 이 Motion-based Segmentation을 통해 배경과 전방객체를 분리하여, rough한 전방객체를 추출하게 된다. 그리고 시간적 분할을 통해 얻은 rough한 전방객체에 모폴로지 변환과 Watershed 알고리즘을 적용하여 배경과 전방객체의 모호한 부분을 제거함으로써 효과적으로 전방객체를 추출한다.

디지털 미디어 기반 익명적 집단성에 대한 인터렉티브 VR 콘텐츠 설계 및 분석

박창근(ChangGeun Park),김여진(Yeojin Kim),전지윤(JiYoon Chun) 한국HCI학회 2019 한국HCI학회 학술대회 Vol.2019 No.2

모폴로지 재구성과 비선형 확산을 적용한 영상 분할 방법

김창근(Changgeun Kim),이귀상(Gueesang Lee) 한국정보과학회 2005 정보과학회논문지 : 소프트웨어 및 응용 Vol.32 No.6

확산(Diffusion)을 이용한 기존의 칼라영상 분할은 확산의 횟수가 반복될수록 경계선 정보가 적절히 유지되지 못하거나 잡음을 제거하지 못함으로써 워터쉐드(Watershed) 알고리즘을 적용하는 경우, 과분할을 피할 수 없다는 단점을 갖고 있다. 본 논문에서는 수리 형태학(Mathematical Morphology)과 비선형 확산(Non-Linear Diffusion)을 함께 적용하여 과분할의 문제점을 제거한 워터쉐드 결과를 얻을 수 있는 칼라영상 분할방법을 제안한다. 임의의 칼라 영상을 LUV 색상공간으로 변환하여, 그 각각의 색상공간에 수리 형태학을 응용한 재구성에 의한 닫힘(Reconstruction) 연산과 비선형 확산을 함께 적용하여 경계선을 적절히 유지하면서 잡음을 제거한 단순 영상을 획득할 수 있다. 이 영상에서 칼라 영상의 기울기(Gradient) 정보를 획득하고, 워터쉐드 알고리즘을 적용하여 영상을 분할한다. 실험 결과, 기존의 방법보다 과분할이 현저히 제거되고, 칼라 영상이 매우 효과적으로 분할됨을 확인하였다. Existing methods for color image segmentation using diffusion can't preserve contour information, or noises with high gradients become more salient as the number of times of the diffusion increases, resulting in over-segmentation when applied to watershed. This paper proposes a method for color image segmentation by applying morphological operations together with nonlinear diffusion. For an input image, transformed into LUV color space, closing by reconstruction and nonlinear diffusion are applied to obtain a simplified image which preserves contour information with noises removed. With gradients computed from this simplified image, watershed algorithm is applied. Experiments show that color images are segmented very effectively without over-segmentation.