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송대규,장영호,김준홍,전국진,이덕희,Zhelong Xu 대한의학회 2010 Journal of Korean medical science Vol.25 No.3
Polyphenol (-)-epigallocatechin gallate (EGCG), the most abundant catechin of green tea, appears to attenuate myocardial ischemia/reperfusion injury. We investigated the involvement of ATP-sensitive potassium (KATP) channels in EGCG-induced cardioprotection. Isolated rat hearts were subjected to 30 min of regional ischemia and 2 hr of reperfusion. EGCG was perfused for 40 min, from 10 min before to the end of index ischemia. A nonselective KATP channel blocker glibenclamide (GLI) and a selective mitochondrial KATP (mKATP) channel blocker 5-hydroxydecanoate (HD) were perfused in EGCG-treated hearts. There were no differences in coronary flow and cardiodynamics including heart rate, left ventricular developed pressure, rate-pressure product, +dP/dtmax, and -dP/dtmin throughout the experiments among groups. EGCG-treatment significantly reduced myocardial infarction (14.5±2.5% in EGCG 1 mM and 4.0±1.7% in EGCG 10 mM, P<0.001 vs. control 27.2±1.4%). This antiinfarct effect was totally abrogated by 10 mM GLI (24.6±1.5%, P<0.001 vs. EGCG). Similarly, 100 mM HD also aborted the anti-infarct effect of EGCG (24.1±1.2%, P<0.001 vs. EGCG ). These data support a role for the KATP channels in EGCG-induced cardioprotection. The mKATP channels play a crucial role in the cardioprotection by EGCG.
채의업,박원균,배재훈,송대규 啓明大學校 醫科大學 1993 계명의대학술지 Vol.12 No.1
This study was attempted to clarify the regulatory mechanism on the systemic and pulmonary vascular reponses through the low pressure receptor, the ventricular performance, and the hormonal changes to the central blood shift at-6˚head-down tilt. In 39 anesthetized dogs(8-14kg), 21dogs (tilt group) were tilted from the supine position to the -6˚head-down position(HDP) for 30 minutes, then back to the supine recovery position for the next 30 minutes. The rest 18 dogs were kept in the supine position without tilt as the control group for the same time course of the tilt group. Cardiac output(Q), heart rate(HR), stroke volume(SV), thoracic fluid volume(TFV),index of ventricular contractility(IC)and ventricular acceleration index(ACI)were determined by the impedance cardiograph(BoMed co). Systemic arterial pressure(SAP) and pulmonary arterial pressure(PAP) were measured at the brachial and pulmonary arteries respectively, and central venous pressure(CVP) also at the right atrium. And the systemic and pulmonary vascular resistances(SVR and PVR) were calculated by dividing SAP and PAP with Q respectively. The concentration of plasma atrial natriuretic peptide(ANP) and antidiuretic hormone (ADH), and plasma renin activity(PRA) in the arterial blood were measured by the radioimmunoassay in 8 dogs in each group at 5 minutes before, and 25 and 55 minutes after beginning of the tilt. At the HDP, TFV increased rapidly and maintained the elevated level during the HDP, where as it decreased gradually in the control group. Q showed the tendency to increase and SAP, PAP and HR did not change significant differences in the changes of HR, PAP and CVP between the tilt and the control group. SVR and PVR reduced in the tilt group, where as they elevated gradually in the control group. There were significant differences in the changes of SVR and PVR between the tilt and the control group at the early stage of HDP. SV, IC and ACI increased at the early stage of HDP in the tilt group, where as they decreased gradually in the control group. Plasma ANP,ADH and PRA did not change significantly in the both groups. In conclusion, the cardiopulmonary baroreceptors induced the vasodilations on both systemic and pulmonary vessels by the central blood shift and the ventricular systolic performance was enhanced at the early stage of the head-down tilt. But the concentration of the plasma ANP and ADH, and PRA did not show significant changes in this study.
토끼 동방결절 세포의 Delayed Rectifier K+ 전류에 미치는 이가 양이온의 차단효과
송대규,호원경,엄융의 啓明大學校 醫科大學 1996 계명의대학술지 Vol.15 No.3
In sinoatrial(SA) node cells, K+ conductance increases only when the membrane is depolarized and the delayed rectifier K+ current, ik, is activated. This leads to repolarizaion which in turn induces the deactivation of channel, causing the membrane potential to depolarize once again towards the threshold of the action potential. Therefore the decay of ik plays a key role in the pacemaker depolarizaion. In the present study, we have investigated the effects of divalent cations(Ni²+, Ba²+, Co²+, and Mn²+) on the delayed rectifier K current in rabbit SA node cells using the whole cell votage clamp technique. CsCl(2 mM) was added to block the hyperpolarizaion activated inward current(ir). K+ currents were recorded in ligh K+ (140 mM) solution. When divalent cations were added to a control solution, they reduced both the instantaneous and the steady-state values of currents recorded on hyperpolarizaion. The blockade was potential-dependent, and steady-state currents were significantly reduced with increasing hyperpolarizaion. The inward currents that recorded during hyperpolarizing voltage steps were relaxed exponetially with time as the blockade by divalent cations developed. Increased the concentraion of the divalent cations elevated the rate of the blockade at a given potential. These phenomena were highly sensitive to temperature, suggesting the presence of ionic binding sites on the channel. Inward K+ currents measured at-80 mV after various depolarizing prepulses(-10 to -40mV) were increased in the more depolarizing prepulses, and showed the steady-state blocking evidence at 0.1 mM Ni²+. Ni²+, Ba²+, Co²+, and Mn²+ had a similar effect, but the velocity of the blocking action is slightly different from one another(Ni²+>Co²+>Mn²+>Ba²+).
송대규(Dae Gyu Song),이준석(Junseok Lee),최홍진(Hong Jin Choi),김정구(Jeong Koo Kim) 한국고분자학회 2022 폴리머 Vol.46 No.1
본 연구는 사람의 안구에 황반변성과 망막 손상을 일으키는 LED digital 기기의 청색광을 차단하는 콘택트렌즈를 개발하여 효과적으로 안구보호와 황반변성 발병률을 줄이기 위하여 시도하였다. 청색광 차단재와 콘택트렌즈용 재료는 각각 coumarin과 poly-methyl-methacrylate(PMMA)이다. PMMA 용해 유기용매로 dichloromethane, chloroform, ethyl acetate, acetone, toluene을 사용하였고 이중 toluene으로 녹였을 때, 시각적인 투명도가 가장 높았고, 강도 또한 가장 높았다. 제작한 렌즈 시편의 coumarin 농도별 흡광도 측정을 통해 청색광 차단율을 확인하였다. 제작한 coumarin/PMMA 콘택트렌즈 시편의 경우 coumarin의 혼합비율에 따라 1, 2.5, 5, 10 mM에 걸쳐 325 ㎚(UV-A) 영역에서는 99% 이상의 가장 높은 차단율을 보였고, 375 ㎚ 영역에서는 1 mM일 때 5.69%, 2.5 mM은 43.34%, 5 mM은 56.45%, 10 mM은 66.25%의 결과를 보였다. 이는 청색광 차단을 위한 coumarin/PMMA 콘택트렌즈가 효과적으로 청색광을 차단하여 자연광 수준으로 낮출 수 있는 것을 알 수 있었다. This study is focused on a contact lens for shielding blue light emitted from LED digital devices, preventing macular degeneration as well as an effective protection of human eyes. For the blue light blocking lens, coumarin was used as blue light blocking material and polymethylmethacrylate (PMMA) was engaged as a material for contact lens. As a solvent for PMMA, dichloromethane, chloroform, ethyl acetate, acetone, and toluene were used and tested. Among the solvents, toluene showed the highest transparency and strength/solidity. For blue light shielding rate, coumarin was administrated with different concentration to the PMMA film, then light absorbance was measured for each specimen. In results, coumarin/PMMA films (contact lens) within 325 ㎚ (UV-A) region, all specimens, 1 mM, 2.5 mM, 5 mM, and 10 mM of coumarin contents PMMA films, showed 99% of blue light shielding rate. In case of 375 ㎚ region, each specimen showed shielding blue light as 5.69% at 1 mM, 43.34% at 2.5 mM, 56.45% at 5 mM, and 66.25% at 10 mM. Conclusively, PMMA contact lenses with coumarin contents reduced the intensity of blue light generated by LED digital devices to the level of natural light.