강자성체에서 상전이의 수치적 모의실험

유대영,양해정,양회룡,정진,최승평,장차익 조선대학교 기초과학연구소 2001 自然科學硏究 Vol.24 No.-

It is difficult to explain the magnetic phase transition with classical physics in Curie temperature. We studied qualitatively with the well known Ising model in statistical mechanics. We simulated systems of finite size by Monte Carlo methods with Metropolis algorithm. Thus we could estimate the values of quantities such as the magnetization(m) per spin the specific heat(c) per spin the magnetic susceptibility(χ) per spin, and the mean energy per spin compare with the numerical values in infinitive size. The quantities of c, m, χ, e varied rapidly within 2.3∼2.4 temperature at J/k units. Those values show that the critical temperature can be within the range. The hysteresis loop was obtained with this model.

Interleukin-6 signaling in podocyte hypertrophy

( Dae Ryong Cha ) 대한신장학회 2016 Kidney Research and Clinical Practice Vol.35 No.4

Mineralocorticoid receptor blockade for renoprotection

( Dae Ryong Cha ) 대한신장학회 2018 Kidney Research and Clinical Practice Vol.37 No.3

Peroxisome Proliferator-Activated Receptor-Alpha Deficiency Protects Aged Mice from Insulin Resistance Induced by High-Fat Diet

Cha, Dae Ryong,Han, Jee Young,Su, Dong Ming,Zhang, Yahua,Fan, Xuefeng,Breyer, Matthew D.,Guan, Youfei S. Karger AG 2007 American journal of nephrology Vol.27 No.5

<P><I>Background/Aims:</I> Insulin resistance is a central feature of the metabolic syndrome and progressively increases with age, resulting in excessively high incidence of type II diabetes in the elderly population. Peroxisome proliferator-activated receptor-α (PPARα) is widely expressed in insulin target tissues, including those of the liver, kidney, and muscle, where it mediates expression of genes promoting fatty acid β-oxidation. The aim of this study was to evaluate the potential role of PPARα in insulin resistance in aging mice induced by a high-fat diet. <I>Methods:</I> We used male PPARα knockout (KO) mice and wild-type (WT) littermates that were 18 months old. Animals were fed with a high-fat diet (HFD) for 4 weeks, and metabolic parameters associated with insulin sensitivity were assessed. <I>Results:</I> Following HFD treatment, WT mice showed more severe insulin resistance than did mice lacking the PPARα gene, as assessed by both the glucose tolerance test (GTT) and insulin tolerance test (ITT). In addition, WT mice exhibited significantly higher HOMA-IR, plasma total cholesterol levels and urinary albumin-creatinine ratio but less liver weight than did PPARα KO mice. <I>Conclusion:</I> These data suggest that PPARα gene deficiency may protect aged mice from developing insulin resistance and albuminuria induced by a HFD.</P><P>Copyright © 2007 S. Karger AG, Basel</P>

Editorial : Where do we stand on human diabetic nephropathy?

( Dae Ryong Cha ) 대한신장학회 2013 Kidney Research and Clinical Practice Vol.32 No.3

Role of aldosterone in diabetic nephropathy

CHA, DAE RYONG,KANG, YOUNG SUN,HAN, SANG YOUB,JEE, YI HWA,HAN, KUM HYUN,KIM, HYOUNG KYU,HAN, JEE YOUNG,KIM, YOUNG SIK Blackwell Science Pty 2005 Nephrology Vol.10 No.suppl2

<P>SUMMARY: </P><P>In the last 10 years, many studies have focused on the non-classical action of aldosterone. One of the most important new aspects of aldosterone is its pathogenic role as proinflammatory and profibrotic molecules. It has been reported that aldosterone induces myocardial fibrosis and vascular inflammation through up-regulation of various proinflammatory and profibrotic cytokines. We investigated the effect of aldosterone and spironolactone, which is a non-selective mineralocorticoid receptor antagonist, on monocyte chemoattractant peptide (MCP-1) and collagen synthesis in cultured mesangial and tubular epithelial cells. In addition, to evaluate the effect of spironolactone on diabetic nephropathy, we used Otsuka Long-Evans Tokushima Fatty (OLETF) rats which are known type 2 diabetic animal models. Spironolactone treatment did not induce any significant change in blood glucose levels and blood pressure. However, spironolactone therapy significantly inhibited urinary albumin and MCP-1 excretion. Spironolactone treatment also suppressed renal mRNA expression for MCP-1, macrophage migration inhibitory factor (MIF) as well as intrarenal protein synthesis for ED-1 and MIF. Morphologically, spironolactone treatment significantly prevented glomerulosclerosis, collagen deposition and connective tissue growth factor (CTGF) expression in diabetic rats. In cultured cell experiments, aldosterone directly increased the MCP-1, collagen secretion and spironolactone treatment abolished aldosterone-induced MCP-1 and collagen synthesis. Surprisingly, aldosterone treatment did not induce any significant change in TGF&bgr;1 gene transcription. Finally, we found that NF-kB activity was increased after stimulation with aldosterone and spironolactone therapy inhibited their activation. In addition, prior treatment with pyrrolidine dithiocarbamate (PDTC), which is a NF-KB inhibitor, inhibited aldosterone-induced MCP-1 protein secretion. These results suggest that aldosterone blockade could play a role in preventing the progression of diabetic nephropathy via anti-inflammatory and antifibrotic mechanisms.</P>

혈액투석 개수 후 단핵구배양 상청액에 의한 사람 근위 세뇨관 상피세포의 Fas 유전자 발현에 대한 연구

차대룡(Dae Ryong Cha),조원용(Won Yong Cho),윤종우(Jong Woo Yoon),조상경(Sang Kyung Jo),김형규(Hyung Kyu Kim),장경현(Kyung Hyun Chang) 대한신장학회 2000 Kidney Research and Clinical Practice Vol.19 No.3

N/A Residual renal function rapidly declines after the initiation of hemodialysis and its mechanisms are supposed to be associated with frequent hypotensive episodes during hemodialysis and subsequent ischemic injury to remnant nephron, but blood-membrane interaction might play an important role because of its ability to activate complement system and other various humoral and cellular mechanisms. Blood monocytes are activated by complements, bacterial conta- minants and activated monocytes are known to secrete multiple proinflammatory cytokines such as TNF-α, IL-1β. The expression of TNF-αand IL-1β in mRNA and protein level were examined by RT-PCR and ELISA respectively in patients with ESRD after the initiation of hemodialysis. Author also investigated the mRNA expression of Fas in human proximal tubular cell culture in the presence of TNF-a and PBMC culture supernatant before and after the ini-tiation of hemodialysis. Compared to PBMC separated before the initiation of HD, the amount of cytokine mRNA from PBMC separated after the initiation of HD showed increased tendency from 0.97±0.2 to 1.12±0.28 for TNF-α(p=0.29), from 1.03±0.18 to 1.10±027 for IL-1β (p=0.54). TNF-αand IL-lβ protein level in PBMC culture supernatant also showed increased tendency from 2.25±0.5 to 4.254±3.77 for TNF- α(p=0.10), from 3.5±2.08 to 4.0±4.3 for IL-1β(p=0,25). TNF-a in-creased Fas mRNA expression dose-dependently com-pared to control but it was not stat.istically significant(p=0,37, 0.22). Compared to the the level of Fas expression in HPTC cultured in the presence of pre HD PBMC supernatant, the level of Fas expression increased significantly in the presence of post HD PBMC supernatant(0.64±057 vs 1.05±0.12, p=0.01). As a conclusion, cytokine gene expression and secretion can increase as a result of blood-membrane interaction and these might have some influence on the loss of residual renal function in CRF patients maintained on hemodialysis.

신 증후 출혈열에 항 호중구 형질항체 검사의 임상적 의의

차대룡(Dae Ryong Cha),김선숙(Sun Sook Kim),이영호(Young Ho Lee),권영주(Young Ju Kwon),조원용(Won Yong Cho),김형규(Hyoung Kyu Kim),조윤정(Yoon Jeong Cho) 대한내과학회 1992 대한내과학회지 Vol.43 No.4

N/A HFRS seems to be systemic vasculitis such as antineutrophil cytoplasmic autoantibody (ANCA) associated disease. Author purposed to investigate the role of ANCA in the pathogenesis of HFRS and its relation with the clinical findings of HFRS. Methods: Author measured ANCA by indirect immunofluorescent method using alcohol-fixed neutrophils as substrate in 14cases of serologically proven HFRS in the patients serum of oliguric and diuretic phase. Results: 1) The study population consisted of 10oliguric and 4nonoliguric HFRS cases. There were no significant difference in clinical manifestations at admission. 2) ANCA were detected positively in 3 of 10oliguric HFRS cases (2 in oliguric stage, 1 in diuretic stage), and all of nonoliguric HFRS cases were negative. 3) Gross hematuria and proteinuria at the time of admission were showed in all of positive cases, and this abnormal urinary fir. dings spontaneously resolved during the hospital course. There were no significant difference in clinical course and laboratory findings between ANCA positive and negative groups. 4) By indirect immunofluorescence microscopy using alcohol-fixed neutrophils as substrate, all positive cases showed typical cytoplasmic staining pattern (C-ANCA) and none had extrarenal disease. 5) All three ANCA positive cases showed negative in follow up measurement of ANCA 6months later after recovery of disease. Conclusion: From the above findings, pathophysiology of vasculitis in hemorrhagic fever with renal syndrome may be related with ANCA in such eases, but further studies are requested in detail.

혈액투석시 Double Lumen Silicone Rubber Catheter ( = Permcath ) 사용의 임상적 경험

차대룡(Dae Ryong Cha),김선숙(Sun Sook Kim),이영호(Young Ho Lee),권영주(Young Joo Kwon),조원용(Won Yong Cho),김형규(Hyoung Kyu Kim),선경(Kung Sun),김정숙(Jung Sook Kim),함인귀(In Gui Ham),김미경(Mi Kyung Kim) 대한내과학회 1994 대한내과학회지 Vol.46 No.4

N/A Background: Repeated, long-term access of the vascular system is a prerequisite for successful extended care of the patients with end stage renal disease (=ESRD) treated with hemodialysis. Despite recent technical advances in percutaneous venous cannulation, vascular access remains a major problem in patients requiring acute Hemodialysis. Although the subclavian cannula has gained a large clinical acceptance in recent years, it carries specific risks such as hemothorax, pneumothorax, venus stenosis, thrombus formation and infection. Recently, a double-lumen, central venous catheter made of Silicone Rubber (=Perm cath) has developed for use as a vascular access device, This device is particularly useful in patients who have exhausted other vascular access sites or who have severe cardiovascular disease. Methods: A total of 23 dual-lumen silicone rubber catheters were placed through the internal jugular vein in 23 patients as a vascular access at our institution during the period of April, 1992 through November, 1992. The perm-cath (Hemocath, Quinton, Seattle) is 36 Cm long and each lumen has an internal diameter of 2 mm. Implantation of the catheters occurred in the operating room and under strict aseptic conditions through the right internal jugular vein. A 10 cm subcutaneous tunnel was then created, which extended from the in-cison to a point 2 cm above the ipsilateral clavicle. The catheter was passed out through the upper portion of the subcutaneous tunnel with the Dacron cuff placed 2 cm from the lower end of the tunnel, acting as both an anchor and a barrier to infection. The tip of the catheter was inserted through an internal jngular vein terminating in the right atrium under EKG monitoring. Each lumen of the catheter was filled with 1000 units of heparin sodium (1.5 ml in venous line, 1.5 ml in arterial line) and capped. Results : The mean duration of catheter use was 24±16 days (8 to 119 days), and the complication of perm-cath occurred in 3 cases such as venous thrombosis in 1 case, catheter exit site infection in 1 case, and exit site hematoma in 1 case. During hemodialysis, blood flow rate ranged from 190 to 313ml/min (mean:235±26ml/ min), and venous retrun pressure ranged from 20 to 150 mmHg(mean:65±16mmHg). Total 14 catheters were removed during treatment and the causes of catheter removal were patient death in 8 cases, venous thrombosis 1, recovery from acute rena1 failure 2, fistula maturation 2, infection 1. Conclusion: Internal jugular vein cannulation with silastic catheter which offers a new percutaneous method was provided safe and reliable as the temporary central vein access. The catheters are well tolerated by the patients and have the advantages of immediate use after placement, high blood flow rates, no repetitive venipuncture, and no cardiac dysfunction. Permcath is particulary useful in patients who have exhausted other vascular access site, severe cardiovascular disease, and terrified by repetitive venipuncture. Though our initial experience has been favorable, there will be needed to evaluate the outcome of permcath over longer period of time.

허혈성 신손상후 c - fos 및 Epidermal Growth Factor 유전자 발현양상

차대룡(Dae Ryong Cha),이영호(Young Ho Lee),장미경(Mi Kyung Jang),김난희(Nan Hee Kim),구자룡(Ja Ryong Koo),권영주(Young Joo Kwon),조원용(Won Yong Cho),김형규(Hyoung Kyu Kim),김창수(Chang Soo Kim) 대한내과학회 1994 대한내과학회지 Vol.47 No.6

N/A Objectives: Acute renal failure (ARF) is a syndrome that can he broadly defined as rapid deterioration of renal function resulting in the accumulation of nitrogenous wastes such as urea and creatinine. The incidence of ARF will most likely increase in the future as a predictable by-product of the continuous advances in surgical techniques and pharmacotherapy. The severity of renal dysfunction after ARF depends on the exent of the initial renal damage as well as the pace of repair process, and the regeneration of tubular epithelial cell is essential in the recovery of ARF. Recently several studies reveal the importance of specific growth factor such as epidermal growth factor (EGF), transforming growth factor-alpha (TGFα) and the expression of these genes is increased during the recovery stage of ARF. To evaluate the expression of c-fos and EGF genes involved in cellular proliferation during acute ischemic renal failure, author performed the northern and dot hybridization of renal tissue at different reperfusion time in the ischemic ARF rats. Methods: The experimental animals were divided into three groups. Group I (n=3) was control without any procedure, group II (n=3) was sham operation group (bilateral flank incision and decapsulation were made without renal artery clamping), group III (n=15) was ischemic ARF model by right nephrectomy and left renal artery clamping for 40 minutes. In ischemic group (Group III), rats were divided into three subgroups according to reperfusion time such as 1, 24, 72 hours (IIIa, IIIb, IIIc in each). For these studies, the non-ischemic right kidney removed at the time of initial surgery served as a paired control. Becaus of inter-animal variation in mRNA content for specific genes, five rats were included for each time period. In all cases, whole blood were collected for measurement of serum creatinine at each reperfusion time. Total renal RNA was purified from intact whole kidneys by deproteinization with guanidinium isothiocyanate and phenol/chloroform/isoamyl alcohol. After the isolation of RNA, electrophoresis were done in a 1% agarose gel containing 20 mM MOPS, 1 mM EDTA, 5 mM Na acetate PH 7.0 and 2.2M formaldehyde and confirmed the intact RNA by the 18 S and 28 S ribosomal RNA. RNA was transferred to nylon membrane via vaccum transfer and then hybridization were performed at 65℃ with isotope labelled probes for 24hours, Autoradiographs were obtained and quantitated by computer-assisted dual- wave length flying spot scanner (CS-9000) at 530 nm. Results: In the control group, the serum creatinine was 0.9±0.2 mg/dl; in the sham operation group 0.8±0.3 mg/dl; in the ischemic group after 1 hour reperfusion, the serum creatinine was 0.9±0.3 mg/dl; In the ischemic group after 24hous and 72 hours reperfusion, the serum creatinine was 1.9±0.5 mg/dl and 3.6±1.4 mg/dl respectively. The mean serum creatinine level was statistically significant between control and post-ischemic 24, 72 hours reperfusion group (p<0.05). c-fos gene was rapidly induced by renal ischemia with peak after 60 minutes of reflow and 24 hours later c-fos message was markedly decreased. The expression of c-fos gene was. more markedly increased in the more severe ischemic injury. EGF gene expression was markedly decreased after 1 hour of reflow and substantially increased in activity ?2 hours after ischemia. Conclusion: From the above findings, c-fos gene expression is rapidly induced by ischemia and this gene expression is essential in the recovery phase of acute ischemic renal failure. EGF gene expression substantially increased in activity is probablely associated with renal epithelial cell proliferation. Although the specific roles of c-fos and EGF genes in tissue recovery are not known, the expression of these genes may be play an important role in the recovery phase of acute ischemic renal failure.