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Protective Effect of Antioxidants on the Reoxygenation Injury in Hypoxic Myocardium of Rat
윤형구,임정규,김명석,Yoon, Hyung-Ku,Lim, Jung-Kyoo,Kim, Myung-Suk The Korean Society of Pharmacology 1988 대한약리학잡지 Vol.24 No.1
저산소 심근의 산소 재공급시에 보이는 심근 손상(oxygen paradox) 기전을 규명하고, 이의 예방법을 찾기 위한 연구의 일환으로 유독성 산소 대사물인 산소 라디칼의 관련성과 지질과산화활성화 및 항산화제의 심근 보호 효과를 검토하였다. 흰쥐 적출 심장을 Langendorff 심장관류법 으로 산소 및 glucose 공급을 중단한 cardioplegic 용액으로 관류 ($37^{\circ}C$, 90분)하여 저산소 상태를 만든 후, 계속해서 산소재공급 관류(20분)를 시행하여 저산소-산소 재공급 심근 손상을 유도 하였다. 심근 손상의 지표로 creatine phosphokinase(CPK), lactic dehydrogenase(LDH)의 관상관류액으로의 유출을, 그리고 지질과산화 척도로는malondialdehyde(MDA) 생성을 측정하였으며, 이에 대한 산소 라디칼 제거물질과 항산화제 ${\alpha}-tocopherol$ 및 butylated hydroxytoluene(BHT)의 효과를 검토하여 다음과 같은 성적을 얻었다. 1. 세포질 효소인 CPK 및 LDH의 유출과 지질과산화산물의 하나인 MDA의 생성은 산소 재공급과 더불어 급격히 증가하였다. 2. 산소 재공급시 세포질 효소의 유출과 MDA 생성은 높은 상관관계를 보였다. 3. Superoxide anion$(O_2)$의 제거 호소인 superoxide dismutase (10,000U), $H_2O_2$ 제거 효소인 catalase (25,000 U) 그리고 hydroxyl radical (OH) 제 거 물질인 dimethylsufoxide(10%)는 세포질 효소의 유출 증가와 MDA 생성 증가를 현저히 억제하였다. 4. 생리적 항산화물질인 ${\alpha}-tocopherol$.of (4.5 uM)과 합성 항산화제인 butylated hydroxytoluene(2 uM)은 산소 공급에 따른 MDA 생성 증가와 세포질 효소의 유출 증가를 용량의존적으로 억제하였다. 5. 항산화제들의 심근 보호 효과는 산소 재공급시 투여할 때보다는 저산소 관류시부터 투여한 경우에 더욱 현저하였다. 이상의 결과에서 저산소 심근의 산소 재공급은 유독성 산소 대사물인 산소 라디칼의 생성을 증가시키며, 그에 따른 지질성분의 과산화가 심근 손상을 일으키는데 관여할 것으로 여겨졌으며, 저산소-산소 재공급 심근 손상은 지질과산화 반응을 억제하는 항산화제에 의하여 방지될 것으로 사료되었다. The effect of antioxidants on the myocardial cellular damage which occurs during reoxygenation of hypoxic myocardium was examined in isolated rat hearts. The roles of oxygen free radical and lipid peroxidation in reoxygenation injury of myocardium were also investigated. In Langenorff preparation of isolated rat heart, which was made hypoxic by perfusion with the substrate free, hypoxic cardioplegic solution ($37^{\circ}C$, 90 min), the release of cytosolic enzymes (creatine phosphokinase, lactic dehydrogenase) and a lipid peroxidation product, malondialdehyde into the coronary effluent were abruptly increased by reoxygenation. The release of enzymes was closely parallel to that of MDA. These increases of enzymes and lipid peroxidation product were suppressed to various degrees in the presence of scavengers of superoxide anion (superoxide dismutase, 10,000 U), hydrogen peroxide (catalase, 25,000 U) and hydroxyl radical (dimethyl sulfoxide, 10%). A natural antioxidant, ${\alpha}-tocopherol$(4.5 uM) and a synthetic one, butylated hydroxytoluene (2 uM) suppressed the release of cytosolic enzymes with the concomittent reduction of lipid peroxidation as measured by malondialdehyde release into the coronary effluent. These effects of antioxidants were dose dependent, and were more pronounced when the antioxidants were administered throughout hypoxic and reoxygenation periods than given during reoxygenation period only. These results suggest that cytotoxic oxygen free radicals produced in the myocardium during reoxygenation may be responsible fur the myocardial cellular injury by enhancing the lipid peroxidation of cellular membranes. Furthermore, the antioxidants may exert protective effect against reoxygenation damage of hypoxic myocardium through the inhibition of lipid peroxidation reaction.
기획·발주, 설계, 건설사업관리 부분의 건설안전관리 향상에 대한 연구
윤형구,권용준,오병한,권영일,윤영근,오태근,Yoon, H.K.,Kwon, Y.J.,Oh, B.H.,Gwon, Y.I.,Yoon, Y.G.,Oh, Tae Keun 한국안전학회 2020 한국안전학회지 Vol.35 No.4
The government has established various policies focusing on accident prevention to reduce the accident rate in the construction industry, but the effect is still insignificant. These results allude that there are still many problems in terms of usability. Although construction safety accidents usually have characteristics that occur during construction, the laws and systems should include the pre-construction cycle (plan/order - design - construction business management- construction) to eliminate risk factors in advance. The purpose of this study is to analyze the performance evaluation of the construction safety system before construction rather than during construction. In the pre-construction phase (plan/ order-design-constuction business management), we intend to investigate and analyze measures to prevent safety accidents and identify a system that lacks the ability to implement. Specifically, we analyzed what to focus on as precautionary measures in the planning, ordering, designing, and supervising. To improve them, we made a questionnaire based on the role related to construction safety for each subject, and seek implications for lack of performance through interviews. Based on the results, some ways to improve the safety system were proposed.
윤형구(Yoon, Hyung-Koo),김준한(Kim, Joon Han),변용훈(Byun, Yong-Hoon),이종섭(Lee, Jong-Sub) 한국구조물진단유지관리학회 2009 한국구조물진단학회 학술발표회논문집 Vol.2009 No.2
The reliable evaluation of design parameters in soft soils has become more important. In particular, the void ratio is an important parameter to understand the soil behavior. The objective of this paper presents the new equation for determining the porosity using elastic waves. The new equation is based on the theory of Gassmann, that is isotropic system, no chemical interaction between soil and fluid, and low frequency. The new equation is function of bulk moduli such as grain, fluid, skeleton and mixture. The bulk modulus of mixture can be estimated using elastic wave velocities, that are shear wave and compressional wave velocities. To verify the proposed equation, the specimens are prepared in the two-type calibration chambers. After measured the elastic wave, the void ratio is assessed by proposed equation. The specimens are also extracted at the top, middle and bottom part to estimate the volume based void ratio. The Foti method, which is based on the Biot theory is used to be compared with the result of new method. The calculated void ratios by proposed equation, volume based and Foti method show the good similarity. This study suggests that the proposed the new method may be a useful equation for assessing the void ratio using elastic wave velocities.
윤형구 ( Yoon Hyung-koo ),짠민콰 ( Tran Minh Khoa ),정순혁 ( Jung Soon Hyuck ),이종섭 ( Lee Jong-sub ) 한국구조물진단유지관리공학회 2009 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.13 No.2
The investigation of soft soils is important to understand the soil behavior. There are many instruments to be able to assess the soil characteristics. In particular, the smaller diameter cone is recommended to estimate the soil behavior due to the high resolution. The objective of this study is to develop the smaller cone, Cone Resistivity Probe(CRP), which can measure the cone tip resistance and electrical resistivity at the tip. The projected area of CRP is 1.76cm2(diameter: 1.5cm) and the length of friction sleeve is designed to 8.4cm with consideration of ratio between projected are and friction sleeve of the standard cone penetrometer. The application test is carried out at the depth of 6~24m in southern area of Korea peninsular. This study suggests that the CRP which can measure the cone tip resistance and electrical resistivity at the tip is useful instrument to understand the soil characteristic.