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The Effects of Melatonin on Cisplatin-Induced Renal Cortical Cell Injury in Rabbits
Chunghui Kim,Jin Han,Nari Kim,Juhee Park,Youngchurl Yang,Euiyong Kim 대한생리학회-대한약리학회 2001 The Korean Journal of Physiology & Pharmacology Vol.5 No.3
<P> Melatonin, a pineal gland hormone, is believed to act as an antioxidant via the stimulation of radical detoxifying enzymes and scavenging of free radicals. In this study, effects of <I>in vitro </I>and<I> in vivo</I> treatments of melatonin on the cisplatin-induced lipid peroxidation, LDH release and plasma creatinine were determined in rabbit renal cortical cells. The level of malondialdehyde (MDA) was assayed as an index of lipid peroxidation and the level of LDH release as an indicator of cellular damage. In <I>in vitro</I> studies, cisplatin increased the levels of MDA and LDH release in a concentration-and time-dependent manner. Melatonin inhibited the cisplatin-induced lipid peroxidation and LDH release in a concentration-dependent manner. The minimal effective concentration of melatonin that significantly reduced the 300μM cisplatin- induced lipid peroxidation and LDH release was 1 mM. In <I>in vivo</I> studies, the levels of lipid peroxidation and LDH release in renal cortical cells increased significantly 24 or 48 hours after a single injection of cisplatin (6 mg/kg). When the cisplatin-injected rabbits were pretreated with 10 mg/kg of melatonin, a significant reduction in both lipid peroxidation and LDH release was observed. The plasma creatinine level increased from 0.87⁑0.07 mg/dl in control to 6.33⁑0.54 mg/dl in cisplatin-injected rabbits (P<0.05). Melatonin partially prevented the increase in serum creatinine level (1.98⁑0.11 mg/dl) by cisplatin (P<0.05). In the proximal tubules from cisplatin-treated group, tubular cells had microvilli of variable heights. Necrotic debris was seen in tubular lumens. In most of cells, the mitochondria and lysosomes were increased in frequency. The endocytic vacuoles were not prominent and distribution of the brush border was irregular and shortened. These cisplatin-induced morphological changes were moderate in the melatonin-pretreated group. These results suggest that the toxicity of cisplatin is associated with the generation of reactive oxygen free radicals and that melatonin is a powerful antioxidant, which prevents some of the adverse effects of cisplatin.
Modulation by Melatonin of the Cardiotoxic and Antitumor Activities of Adriamycin
Kim, Chunghui,Kim, Nari,Joo, Hyun,Youm, Jae Boum,Park, Won Sun,Cuong, Dang Van,Park, Young Shik,Kim, Euiyong,Min, Churl-Ki,Han, Jin Lippincott Williams Wilkins, Inc. 2005 Journal of cardiovascular pharmacology Vol.46 No.2
In this study, we investigated the effects of melatonin on adriamycin-induced cardiotoxicity both in vivo in rats and in vitro, and on the antitumor activities of adriamycin on MDA-231 and NCI breast cancer cells. Rats that received a single intraperitoneal injection of 25 mg/kg adriamycin showed a mortality rate of 86%, which was reduced to 20% by melatonin treatment (10 mg/kg, SC for 6 days). Melatonin attenuated adriamycin-induced body-weight loss, hemodynamic dysfunction, and the morphologic and biochemical alterations caused by adriamycin. Melatonin also reduced adriamycin-induced nuclear DNA fragmentation, as assessed by the comet assay. In addition, the antitumor activity of adriamycin could be maintained using lower doses of this drug in combination with melatonin. Melatonin treatment in the concentration range of 0.1-2.5 mM inhibited the growth of human breast cancer cells. In terms of oncolytic activity, the combination of adriamycin and melatonin improved the antitumor activity of adriamycin, as indicated by an increase in the number of long-term survivors as well as decreases in body-weight losses resulting from adriamycin treatment. These results indicate that melatonin not only protects against adriamycin-induced cardiotoxicity but also enhances its antitumor activity. This combination of melatonin and adriamycin represents a potentially useful regimen for the treatment of human neoplasms because it allows the use of lower doses of adriamycin, thereby avoiding the toxic side effects associated with this drug.
김충희 ( Chunghui Kim ),한상욱 ( Sangwook Han ),김현철 ( Hyunchul Kim ),박영균 ( Youngkyun Park ),김영진 ( Youngjin Kim ) 한국액체미립화학회 2018 한국액체미립화학회 학술강연회 논문집 Vol.2018 No.-
As the number of revolutions of the sprocket increased, the overall noise of the system and the chain noise increased linearly. The maximum noise was overall noise 87.4dB(A) and chain noise 65dB(A) at 7,000rpm. Further research is needed on the resonance caused by the tension applied to the chain and the system structure in the future and the change of the noise characteristics accordingly.
냉각 갤러리 형상이 디젤엔진 피스톤 온도에 미치는 영향
김충희(Chunghui Kim),신윤섭(Yunsub Sin),이기수(Geesoo Lee),김현철(Hyunchul Kim),유연설(Younsul Yoo),김희수(Heesu Kim) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5
The weakest point in the piston of the engine is a piston bowl edge where mechanical and thermal loads are directly transferred. One of the promising technologies to complement this issue is remelting piston crown, which increases the durability and strength of the piston. In this study, experimental study was carried out with three types of pistons (base piston, re-melting piston, and down gallery piston). Piston surface temperature was measured for the purpose of . Numerical analysis using FEM was then conducted to evaluate the experimental results. It was revealed that re-melting piston can apply to the conventional diesel engine since the piston temperature from a re-melting piston applied engine was almost the same with that from base piston engine without sacrifice of power and torque.
디젤 엔진용 Re-melting 강화 기술을 적용한 피스톤의 성능 특성
김충희(Chunghui Kim),신윤섭(Yunsub Sin),이기수(Geesoo Lee),김현철(Hyunchul Kim),유연설(Younsul Yoo),김희수(Heesu Kim) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
The thermal performance characteristics and engine validation tests are carried out to investigate re-melting reinforced cast aluminum pistons of which the bowl rim area are welded by the technology of tungsten inert gas (TIG). Diesel engine technology have progressively resulted in continuous advanced in specific power, presently reaching 70kW/L in order to cost-effectively meet demanding regulation and fuel economy. The newly designed pistons can satisfy the desirable design option for thermo-mechanical fatigue and high cycle fatigue in critically loaded areas. The combustion bowl re-melting process is described and engine validation tests such as engine power, torque and cylinder pressure are performed and show to equivalent level of a base engine. In addition, the effects of the cooling gallery on the piston temperature are studied by using templugs, which are temperature sensitive steels and are used for determining the maximum temperature in locations.
Warm-up characteristics of a gasoline engine with the exhaust heat recovery system
( Chunghui Kim ),( Sangwook Han ),( Hyunchul Kim ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-
The exhaust heat recovery system uses heat energy of the exhaust gas for the heat exchange between the exhaust gas and the coolant at the cold start duration. It shortens the warm-up time and thus improve the fuel economy due to the initial friction loss reduction. In this study, the warm-up characteristics of a gasoline engine with exhaust heat recovery system (EHRS) was analyzed in the engine and the vehicle, respectively. In the engine test, the coolant temperature of EHRS outlet was higher than that of inlet at the beginning of cold start. This was because of heat transfer from exhaust gas to coolant. However, its effect is not significant in the low load condition because heat from exhaust gas was used to warm up the EHRS itself and coolant quantity also increased. In high load condition, on the other hand, it resulted in fast warm-up of the coolant by the sufficient heat energy for the warm-up. In addition, the various parametric studies were conducted and analyzed in the engine test. In the vehicle test, both EHRS and ATF Warmer/Cooler were installed for better fuel economy. The results showed the remarkable increase in ATF temperature and thus improved the fuel economy at the FTP-75 mode.