Oxidative Stress and Chronic Allograft Nephrothy

하헌주,박재현,김유선,Hitoshi Endou 연세대학교의과대학 2004 Yonsei medical journal Vol.45 No.6

Oxidative stress defined as outbalanced generation of reactive oxygen species (ROS) than the existing antioxidative defense mechanisms plays an important role in tissue injury. Ischemia/reperfusion accompanied during organ transplantation is well- established oxidative stress-induced tissue injury. We hypothesized that oxidative stress may also play a role in the development and progression of chronic allograft nephropathy (CAN), since that ROS are major signaling molecules of growth factors and cytokines [platelet-derived growth factors, transforming growth factor-β1 (TGF-β1)] upregulated in the kidney of CAN, that ROS in turn upregulate TGF-β1, and that mycophenolic acid may inhibit features of CAN [proliferation and extracellular matrix (ECM) accumulation in vascular smooth muscle cells and glomerular mesangial cells] through inhibiting cellular ROS. Cellular ROS activate signal transduction cascade (protein kinase C, mitogen-activated protein kinases, and janus kinases) and transcription factors (nuclear factor-κB, activated protein-1, specificity protein 1, and signal transducers and activators of transcription) leading to regulation of genes and proteins involved in cellular proliferation, ECM remodeling, and apoptosis accompanied in CAN. This review is intended to provide an overview of oxidative stress in renal allograft nephropathy.

항산화제 투여가 stretozotocin 당뇨쥐의 단백뇨와 사구체의 TGF - B1 및 fibronectin mRna 표현에 미치는 영향

하헌주,유미라,김경환 대한신장학회 1998 춘계학술대회 초록집 Vol.1998 No.-

노화와 산화성스트레스

하헌주 대한임상노인의학회 2005 대한임상노인의학회지 Vol.6 No.1

영업담보제도의 법리와 도입방안

하헌주 한국기업법학회 2004 企業法硏究 Vol.0 No.16

Although it is advisable for a person entering into a loan or credit agreement with a company to secure the advancement of funds by means of a fixed charge, a company may have already created a fixed charge over the particular asset with which the subsequent creditor wishes to secure his loan. In such circumstances, priority issues may deem that it is not in the subsequent creditor’s interests to secure his loan by means of a second fixed charge. Indeed, the merits of taking a second fixed charge will depend upon the value of the asset in relation to the amount of credit which the first fixed charge purported to secure. Where circumstances are such so as to render the creation of a subsequent fixed charge or mortgage ineffectual, a creditor may secure his loan by means of the floating charge. After discussing the nature of the specific problems to the company’s property, I concluded that some provisions should be prescribed to protect company capital economic interests.

美國 統一商法典 第9編 擔保付去來上의 浮動擔保

하헌주 한국재산법학회 2003 재산법연구 Vol.20 No.1

Article 9 of the Uniform Commercial Code covers most aspects of the creation, perfection and enforcement of a security interest in almost any kind of tangible or intangible personal property and fixtures, given by a debtor to a secured party to secure the performance of an obligation of almost any kind. The property in which a security interest is to be created, the collateral. may include property owned when the security agreement is entered into or property to be acquire thereafter. The obligation secured will usually be one incurred to acquire the collateral or one incurred through the contemporaneous, past or future borrowing of money. Although a few of the rules vary with the nature of the debtor, generally one set of rules governs all security transactions. It is sometimes alleged that through the combined effect of a number of provisions, article 9 permits the debtor to create a floating lien, tying up all of this assets with one creditor and hampering his ability to get credit from anyone else. The lien floats from one bit of collateral to another, and may first secure one debtor and then another. The provisions of article 9 about which discussion of the floating lien centers include those which permit the debtor (i) to hypothecate any Dr all of his personal property, including after-acquired property, the lien on the property following over into products into which it is wrought or commingled, or proceeds resulting from its disposition; (ii) to give present security for future advances; (iii) to use with respect to any kind of collateral the notice filing heretofore restricted to inventory and accounts receivable; and (iv) to exercise such dominion or contra over the collateral as may be agreed upon between the parties.

제 21 차 대한신장학회 춘계학술대회 초록집 / 일반연제 : Diabetic Nephropathy and Hypertension ; 당뇨 흰쥐 신장내 protein kinase Cδ 와 ε 의 활성화에 있어서 산화성스트레스의 역할

하헌주,유미라,이희발 대한신장학회 2001 춘계학술대회 초록집 Vol.2001 No.-

N/A

사람 폐 섬유아세포의 전환성장인자-β1에 의한 fibronectin 분비와 α-smooth muscle actin 표현에 있어서 활성산소족의 역할

하헌주,유미라,어수택,박춘식,이희발,Ha, Hunjoo,Yu, Mi-Ra,Uh, Soo-taek,Park, Choon Sik,Lee, Hi Bahl 대한결핵및호흡기학회 2005 Tuberculosis and Respiratory Diseases Vol.58 No.3

연구배경 : 전환성장인자-${\beta}1$(transforming growth factor-${\beta}1$: $TGF-{\beta}1$)은 폐 섬유화를 매개하는 주된 인자이지만 $TGF-{\beta}1$에 의한 폐 섬유화의 발생과 진행기전의 이해는 아직 불완전하다. $TGF-{\beta}1$은 다양한 세포에서 활성산소족(reactive oxygen species: ROS)을 통하여 세포내 신호를 전달하고 ${\alpha}$-smooth muscle actin (${\alpha}$-SMA)의 신생합성을 통하여 상피세포와 폐 섬유아세포를 근 섬유아세포 표현형으로의 변화를 유도하는 주된 인자이다. ROS는 또 다양한 세포에서 세포외기질 (extracellular matrix: ECM) 축적을 유발하는 것이 알려져 있음으로 본 연구에서는 폐 섬유아세포인 MRC-5 세포에서 $TGF-{\beta}1$이 ROS를 매개하여 fibronectin 분비와 ${\alpha}-SMA$ 표현의 증가에 관여하는지를 검색하였다. 방 법 : 성장이 동일화된 MRC-5 세포를 $TGF-{\beta}1$ (0.2-10ng/ml)으로 96 시간까지 자극하였고, 필요에 따라 항산화제인 N-acetylcysteine (NAC)이나 NADPH oxidase 억제제인 diphenyleniodonium (DPI)을 $TGF-{\beta}1$ 투여 1 시간 전부터 전처리하였다. Dichlorofluorescein (DCF)에 민감한 세포내 ROS는 FACS로, 분비된 fibronectin과 세포의 ${\alpha}-SMA$ 표현은 Western blot 분석으로 측정하였다. 결 과 : $TGF-{\beta}1$은 용량의존적으로 fibronectin 분비와 ${\alpha}-SMA$ 표현을 상향조절하였다. NAC와 DPI는 $TGF-{\beta}1$에 의한 fibronectin 분비 증가와 ${\alpha}-SMA$ 상향조절을 유의하게 억제하였다. $TGF-{\beta}1$에 의한 세포내 ROS의 증가도 NAC나 DPI에 의하여 유의하게 억제되었다. 결 론 : 본 연구의 결과는 폐 섬유아세포에서 NADPH oxidase 에 의하여 생산된 ROS가 $TGF-{\beta}1$에 의한 fibronectin 분비와 ${\alpha}-SMA$ 표현을 상향조절함으로써 폐 섬유화의 발생과 진행에 관여할 수 있음을 증명하였다. Background : The transforming growth $factor-{\beta}1$ ($TGF-{\beta}1$) plays a key role in lung fibrosis. However, the molecular mechanisms involved in $TGF-{\beta}1$-induced lung fibrosis are unclear. $TGF-{\beta}1$ is the key inducer of myofibroblast transdifferentiation via de novo synthesis of ${\alpha}-smooth$ muscle actin (${\alpha}-SMA$). Since $TGF-{\beta}1$ signals through reactive oxygen species (ROS) and ROS have been shown to induce accumulation of extracellular matrix (ECM) in various tissues, this study examined if ROS play a role in $TGF-{\beta}1$-induced fibronectin secretion and ${\alpha}-SMA$ expression in human lung fibroblasts, MRC-5 cells. Methods : Growth arrested and synchronized MRC-5 cells were stimulated with $TGF-{\beta}1$ (0.2-10 ng/ml) in the presence or absence of N-acetylcysteine (NAC) or diphenyleneiodonium (DPI) for up to 96 hours. Dichlorofluorescein (DCF)-sensitive cellular ROS were measured by FACScan and secreted fibronectin and cellular ${\alpha}-SMA$ by Western blot analysis. Results : $TGF-{\beta}1$ increased the level of fibronectin secretion and ${\alpha}-SMA$ expression in MRC-5 cells in a dosedependent manner. Both NAC (20 and 30 mM) and DPI (1 and $5{\mu}M$) significantly inhibited $TGF-{\beta}1$-induced fibronectin and ${\alpha}-SMA$ upregulation. The $TGF-{\beta}1$-induced cellular ROS level was also significantly reduced by NAC and DPI. Conclusions : The results suggest that NADPH oxidase-dependent ROS play an important role in $TGF-{\beta}1$-induced fibronectin secretion and ${\alpha}-SMA$ expression in MRC-5 cells, which leads to myofibroblast transdifferentiation and progressive lung fibrosis.

UV Curing Kinetics and Properties of Polyurethane Acrylate/Multi-walled Carbon Nanotube Coatings

하헌주,김성철,하기룡 한국고분자학회 2010 Macromolecular Research Vol.18 No.7

Polyurethane (PU) acrylate/multi-walled carbon nanotube (MWNT) composite coatings were synthesized by simple UV irradiation at ambient temperature. In particular, aromatic PU acrylate and aliphatic PU acrylate were chosen to examine the effect of the π-π interaction between the MWNTs and the aromatic PU acrylate. The electrical properties showed that the incorporation of only a few hundred MWNT in wt% was sufficient for electrostatic dissipative applications. Other properties, such as the rheological properties and transparency were also examined.

Morphology and Properties of Polyamide/Multi-walled Carbon Nanotube Composites

하헌주,김성철,하기룡 한국고분자학회 2010 Macromolecular Research Vol.18 No.7

The effect of van der Waals force interactions between multi-walled carbon nanotubes and the polymer matrix was examined using three different types of polyamides: polyamide 6, polyamide 11 and polyamide 12. A comparison of the degree of dispersion of multi-walled carbon nanotubes in the polymer and the measured physical properties showed that the hydrophobicity of the polymer matrix is an important factor for determining the properties of the polyamide nanocomposite material. Polyamides with longer hydrophobic methylene groups in the repeating unit had a better dispersion of multi-walled carbon nanotubes and correspondingly lower surface resistivity.

당뇨병성 신증의 발생과 진행에 관여하는산화성 스트레스의 역할

하헌주,김경환 대한신장학회 1997 추계학술대회 초록집 Vol.1997 No.-