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실험적 급성 허혈성 신부전에서 Verapamil 이 혈중 Polyamine 동태에 미치는 영향
원동준(Dong Jun Won),권현민(Hyun Min Kwon),김용섭(Yong Seop Kim),구자룡(Ja Ryong Gu),권영주(Young Ju Kwon),조원용(Won Yong Cho),김형규(Hyung Kyu Kim) 대한내과학회 1991 대한내과학회지 Vol.40 No.6
It has been proposd that calcium entry from an external medium increases intracellular free calcium to toxic levels during ischemic acute renal failure, and verapamil (ARF) has been suggested as the agentblocking calicium entry into renal cells and protecting renal function during ischemic injury. Polyamines, anorganic cations that play various roles in normal cellular proliferation and differentiation, accumulate in renal failare. Alsa it has been suggested tht the synthesis and metabolism of polyamine are influence by acute changes of the general condition, such as acute renal failure, and are mediated by a calcium influx into the cells. The study was designed to study the protective effects of systemic verapamil pretreatment on renal function and the influence on polyamine metabolism in experimental ischemic ARF in cats. For these purpose, the experimental animals were divided into 2 groups. While Group I (n=5) was an ischemic ARF model by renal artery clamping for 60 minutes, Group II (n=5) was ischemic ARF with systemic verapamil (5 ml/min/kg) pretreatment. The creatinine clearance and plasma and urinary polyamine were measured in each group before and after the renal artery clamp. The results were as follows: 1) Creatinine clearance before and after the renal artery clamp were 10.64±7.18 ml/min/kg and 2.09±1. 70 ml/min/kg in Group I, 4.47±3.38 ml min/kg and 0.60±0.79ml/min/kg in Group II, respectively, So creatinine clearance decreased more significantly in Group II campared with Group I. 2) Plasma polyamine increased after ischemia in Group I. In group I, plasma levels of putrescine, spermidine, and spermine before ischemia were 4.75±0.40 nmol/ml, 0.69±0.09 nmol/ml, and 0.83±0.63 nmol/ml, were elevated to 7.17±2.91 nmol/ml, 9.83±1.46 nmol/ ml, and 2.64±1.14nmol/ml after ischemia. But in Group II, the plasma level of polyamine was not changed, and especially, spermine decreased significantly from 0.83±0.27 before ischemia to 0.49±0.23 nmol/ml after ischenmine (p=0.033). 3) Urine polyamine excretion decreased after ischemia in Group I and Group II. In Group II, urinary excretion of spermidine and spermine before ischemia, 0.13±0.10 nmol/min and 0.17±0.13nmol/min, decreased after ischemia to 0.01±0.01nmol/min (p=0.019) and 0.032±0.26 nmol/min (p=0.0257). 4) In renal tissue, spermine content vas highest. In Group II, preischemic spermine were 397.20 nmol/g and increased to 646.66nmol/g after ischema, But there were no significant changes in the polyamine contents in Group II. From these data, it was suggested that systemic verapamil pretreatment exerts no protective effect on ischemic ARF. Plasma polyamines are elevated in ischemic ARF, and verapamil may protect these elevations.
권현민(Hyun-Min Kwon),권정태(Jeong-Tae Kwon) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.9
심층수와 표층수의 온도 차이를 이용하는 히트펌프 시스템이나 해수열원 발전시스템(OTEC)의 열교환기는 해수의 염분에 의하여 발생하는 열교환기의 표면 위에서의 부식 현상에 의하여 열전달 성능이 저하된다. 본 연구는 이중관식 열교환기 실험을 통하여 부식시간에 따른 열전달저하를 실험하고 분석한 내용을 제시한다. 이러한 연구는 고가의 티타늄 열교환기를 대체하기 위하여 알루미늄에 전착 코팅을 하여 제작된 코팅 관을 통해 수행되었다. 코팅 두께 10, 15, 20μm의 알루미늄 관 및 티타늄 관을 각각 6주, 12주, 18주씩 가속 부식시킨 후에 이중관 열교환기 실험을 통하여 코팅 두께 및 부식 시간에 따른 열전달의 변화를 측정하고 분석하였다. 코팅이 얇을수록 더 빠르게 블리스터 현상이 발생하였다. 15μm의 코팅 관의 경우 12주 부식까지는 좋은 열전달 성능을 보였으나, 18주 부식의 경우에서 열전달 성능의 감소를 보였다. 연구결과로부터 본 실험 조건에서는 20μm의 두께로 코팅된 알루미늄관이 티타늄을 대체할 수 있는 열전달 성능을 가질 수 있음을 확인하였다. 또한, 부식 시간에 따른 부식 열저항의 증가에 대한 고찰을 통하여 향후 부식 열저항모델 개발의 방법론을 제시하였다. Heat pump systems based on ocean thermal energy conversion (OTEC) systems use the temperature difference between deep ocean water and surface ocean water to operate. However, they may have heat transfer degradation due to corrosion on the heat exchanger surface due to the salinity of sea water. This study presents experimental results for the heat transfer decrease of corroded metal tubes with respect to corrosion time. In order to replace high-priced titanium, electro-deposition (ED) coating was performed on aluminum tubes. Aluminum tubes with ED coating thicknesses of 10, 15, and 20 μm were tested for double-tube heat exchangers after performing accelerated corrosion for 6, 12, and 18 weeks. The effects of the coating thickness and the corrosion time on the heat transfer degradation were investigated. From the results, the aluminum tube with an ED coating of 20 μm thickness can be suggested as a candidate for replacing titanium tubes.
지속성 외래 복막투석중인 당뇨성 신부전에서 Verapamil 의 복강내 투여가 β2 - Microglobulin 에 미치는 영향
변현주(Hyun Ju Byun),차대룡(Dae Ryong Cha),권현민(Hyun Min Kwon),권영주(Young Ju Kwon),조원용(Won Yong Cho),김형규(Hyoung Kyu Kim) 대한내과학회 1991 대한내과학회지 Vol.41 No.5
In diabetic renal failure, generalized vasculopathy including capillaries is presented, and so there may be some difference in ultrafiltration and mass transport from that of non-diabetic renal failure. Recently, several studies show that intraperitoneal administration of Ca++ antagonist may increase ultrafiltration and mass transport of small molecular weight substance in CAPD. It suspected that the effect of intraperitoneal administration of verapamil on CAPD, may have different response in diabetic and non-diabetic renal failure. In order to evaluate the effects of calcium antagonist (verapamil) on the permeability of the peritoneal membrane in patients on CAPD, serum levels and clearances of creatinine, urea, and β2-Microglobulin, mass transferarea coefficient, ultrafiltration rate and glucose absorption were measured. The study group was devided by 5 non-diabetic (age 33.4+12.4 years, treated for 10.1+8.4 months, Group I) and 5 diabetic (age 53.2+13.7 years, treated for 16.6+15.2 months, Group II) renal failure patients and the study was carried out using 1.65% dextrose dialysate solution for 240 minutes dwell time (phase I), and after the intraperitoneal administration of 10 mg of verapamil the peritoneal dialysis was done by same method as phase I (1phase II). To evaluate the effects of verapamil, percent difference of change between phase I and phase II was calculated. All the values here are mean. The results are: 1) Serum levels of creatinine and β2-Microglobulin were lower in Group II (11.4 vs 6.8 mg/dl, 39.4 vs 18.2 mg/dl) (p<0,01). 2) Peritoneal clearance of creatinine was higher in Group II (6.322 vs 7.072 ml/min), but the increasing rate after instillation of verapamil was slightly lesser than Group I (6.5 vs 4.0%) (not significant). 3) Peritoneal clearance of β2-Microglobulin was higher in Group II (0.626 vs 0.88 ml/min), and the increasing rate after instillation of verapamil was marked in both group, especially in Group I (83.5 vs 36.1%) (not significant). 4) MTAC was higher in Group II (9.7 vs 12.78 ml/min), but the increasing rate of it was greater in Group I (15.4 vs 3.58%) (not significant). The peritoneal permeability was greater in Group 1I probably due to increased permeability and changed structures of peritoneal capillaries in diabetic disease, and the effects of calcium antagonist (verapamil) on peritoneal permeability was lesser in Group II. It suggests that the intraperitoneal administration of verapamil increase the efficiency of CAPD in general, but the benefit may be lesser in diabetic patients.