• Journal of Chest Surgery
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• v.34 no.3
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• pp.203-211
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• 2001

배경: AT$_1$수용체의 길항제가 세포 수준에서 심근을 재관류 손사으로부터 보호할수 있다는 것으로 알려져 있지만, 생체내에서의 효과나 그 기전은 아직 명확히 밝혀지지 않았다. 본 연구에서는 백서 심근 허혈 모델을 이용하여, AT$_1$ 수용체의 길항제들 중 하나인 irbesartan이 심근이 재관휴 손상에 미치는 효과를 알아보고, 재관류 손상을 매개하는 한 각지 기전으로서 세포자멸의 기여에 대하여 연구하고자 하였다. 대상 및 방법: Sprague-Dawley 백서에서 무작용 부형약(10% gum arabic: 1군, 개체수=14관) irbesartan(50mg/kg/day :II 군, 개체수=12)을 각각 3일 동안 24시간마다 경구로 투여하였다. 실험동물의 좌 관상 동맥을 45분간 결찰하였다가, 그 후 2시간 동안 재관류시킨 다음 심장을 적출 하였다. TTC(triphenyltetrazolium chloride) 염색법을 이용하여, 허혈 노출 부위에 대한 심근 경색 부위의 비율을 측정하였다. Agarose gel 전기영동상의 DNa 분절 양상과 TUNEL(TdT-mediated dUCP nick end labeling) 염색을 관찰하여 세포자멸이 일어난 정도를 평가하였다. 세포자멸을 조절하는데 관여하는 것으로 알려진 Bcl-2(B-cell lymphoma 2 gene), Bad 등의 단백과 ERK (extracellular signal-regulated kinase), p-38 등 신호전달체계에 작용하는 MAPKs(mitogen-activated protein kinases)의 발현을 측정하기 위하여 Western blot을 시행하였다. 결과: 허혈 노출부위에 대한 심근 경색부위의 비율은 II군(42$\pm$2.7%)이 I군( 64.1$\pm$4.65)에 비해 유의하게 작았다.(p< 0.05), Agarose gel 전기영동상의 DNA laddering 양상은 I군에서 보다 높게 발현되었다. Bad와 ERK2의 발현은 두 군간에 유의한 차이가 없었다. 결론: AT$_1$수용체 길항제인 irbesartan은 생체에서 심근의 재관류 손상을 줄이는 효과가 있었다. 이 효과는 적어도 부분적으로 나만 심근세포의 세포자멸이 감소한 것에 기인한 것으로 설명할 수 있으며, 이 항-세포 자멸 효과는 Bcl-2의 발현증가와 관련이 있는 것으로 추정되었다.

• Childhood Kidney Diseases
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• v.3 no.1
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• pp.20-26
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• 1999

Purpose : Several modulatory factors for renal peripheral benzodiazepine receptor (PBR) has been reported, but their physiological significance remains elusive. Tissue-specific, stress-induced down-regulation of renal PBR coupled with the pharmacological stimulation of these effects by angiotensin II suggested that physiological significance of renal PBR may be related to the pathophysiology of stress-induced hypertension. The boderline hypertensive rat (BHR) has been used extensively to study the interaction of environmental factors, such as stress and blood pressure. The BHR is the first-generation progeny of a cross between the spontaneously hypertensive rat and the control Wistar-Kyoto rat. The pathogenesis of stress induced hypertension in this model is not demonstrated well. Methods In this study, BHR (male, 150-200 g) and Sprague-Dawley (SD, male, 150-200 g) rats were treated by repeated immobilization to induce anxiety. We used plus-maze performance to observe the level of anxiety by measuring percent open crosses and percent time in open. Results : Percent open crosses and percent time in open in BHR were lower than in SD rats (P<0.05). Receptor densities of renal PBR in BHRs were significantly lower than those of SDs (P<0.05). We also observed that the renal PBR was upregulated in the repeatedly stressed (immobilization, 2 hours daily, for 2 weeks) rats, both in the BHR and SD. However, the density of renal PBR in the stressed BHR was still lower than that of stressed SD. Renal PBR has been suggested to be an important organs which Is responsible for the production of cholesterol-derived products during stress. Conrlusion : From these results, it can be summarized that the lowed density of renal PBR may be involved in the pathogeneis of stress-induced hypertension.

• Korean Journal of Clinical Pharmacy
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• v.21 no.2
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• pp.122-130
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• 2011

Objective: Although recombinant human erythropoietin (rhEPO) has revolutionized the treatment of anemia in chronic kidney disease (CKD) receiving hemodialysis (HD) with no need of blood transfusion, some patients have a blunted or appear to be resistant to rhEPO. There is a controversy in the causes of rhEPO resistance in maintenance HD patients with anemia. This study is to examine current anemia treatment outcomes and the factors influencing the rhEPO responsiveness in HD patient with CKD. Methods: The clinical parameters or factors relating to erythrompoietin treatment outcomes and erythropoietin responsiveness were collected from the HD patients in two large dialysis centers for three months. The collected paramenters included serum iron, total iron biding capacity (TIBC), transferrin saturation rate, ferritin, albumin, intact PTH, C-reactive protein (CRP), nPCR and medications such as an angiotensin converting enzyme inhbitor, an angiotension II receptor blocker and an HMG-CoA reductase inhibitor (HMG-CoA RI). The data were analyzed to examine the degree of acheiveing the anemia treatment goal and factors relating to ERI. Results: Among total 111 patients, 42 (42.3%) and 47 (37.8%) patients achieved the target Hct and Hb based on the Health Insurance Review and Assessment Services (HIRA) reimbursement criteria. In the higher ERI group (upper quartile), the patients had higher CRP levels (0.5 mg/dl) (p=0.0096), and lower TIBC score (<$240{\mu}g/dl$) (p=0.0027), and less patients were taking HMG-CoA RI (p=0.0019). Male patients (p=0.0204), patients with high TIBC score ($R^2$=0.084, p=0.0021) and patients taking HMG-CoA RI (p=0.0052) required to administer less dose of rhEPO meaning higher erythropoietin responsiveness. Conclusion: Less than 50% of CKD patients were achieving the goals of anemia by erythropoietin administration in large hospitals in Korea even though the goals were lower than those of NKF-K/DOQI practice guideline. The factors influencing ERI were sex, TIBC and HMG-CoA RI administration status, and neither an ACEI nor an ARB did not influence ERI.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.6
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• pp.661-670
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• 2018

Fimasartan, a new angiotensin II receptor antagonist, reduces myocyte damage and stabilizes atherosclerotic plaque through its anti-inflammatory effect in animal studies. We investigated the protective effects of pretreatment with fimasartan on ischemia-reperfusion injury (IRI) in a mouse model of ischemic renal damage. C57BL/6 mice were pretreated with or without 5 (IR-F5) or 10 (IR-F10) mg/kg/day fimasartan for 3 days. Renal ischemia was induced by clamping bilateral renal vascular pedicles for 30 min. Histology, pro-inflammatory cytokines, and apoptosis assays were evaluated 24 h after IRI. Compared to the untreated group, blood urea nitrogen and serum creatinine levels were significantly lower in the IR-F10 group. IR-F10 kidneys showed less tubular necrosis and interstitial fibrosis than untreated kidneys. The expression of F4/80, a macrophage infiltration marker, and tumor necrosis factor $(TNF)-{\alpha}$, decreased in the IR-F10 group. High-dose fimasartan treatment attenuated the upregulation of $TNF-{\alpha}$, interleukin $(IL)-1{\beta}$, and IL-6 in ischemic kidneys. Fewer TUNEL positive cells were observed in IR-F10 compared to control mice. Fimasartan caused a significant decrease in caspase-3 activity and the level of Bax, and increased the Bcl-2 level. Fimasartan preserved renal function and tubular architecture from IRI in a mouse ischemic renal injury model. Fimasartan also attenuated upregulation of inflammatory cytokines and decreased apoptosis of renal tubular cells. Our results suggest that fimasartan inhibited the process of tubular injury by preventing apoptosis induced by the inflammatory pathway.

• Journal of Pharmaceutical Investigation
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• v.40 no.1
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• pp.51-57
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• 2010

Losartan potassium, 2-butyl-4-chloro-1-[p-(o-1H-tetrazol-5-ylphenyl)benzyl]imidazole-5-methanol mono-potassium salt, is a new class of antihypertensive agents, and is an antagonist in angiotensin receptor. The purpose of the present study was to evaluate the bioequivalence of two Losartan potassium tablets, Cozaar tablet (MSD Pharmaceutical Co., Ltd.) and Losata tablet (Kyung Dong Pharmaceutical Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The release of losartan from the two losartan potassium formulations in vitro was tested using KP VIII Apparatus II method with various dissolution media. Twenty eight healthy male subjects, $23.86{\pm}1.80$ years in age and $67.27{\pm}6.60\;kg$ in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After a single tablet containing 50 mg as losartan potassium was orally administered, blood samples were taken at predetermined time intervals, and the concentrations of losartan in serum were determined using HPLC with fluorescence detector. The dissolution profiles of two formulations were similar in all tested dissolution media. The pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ were calculated, and Equiv Test/K-BE Test 2002 was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, Cozaar, were -2.70%, 1.45% and 2.31% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 (e.g., log 0.8852~log 1.0655 and log 0.8319~log 1.2342 for $AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Losata tablet was bioequivalent to Cozaar tablet.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.154-165
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• 2010

Purpose : We know little about the natural course of IgA nephropathy (IgAN) in association with histologic changes especially in children. We investigated clinicopathologic features with long-term follow-up biopsy to clarify the outcomes and prognostic indicators for childhood IgAN. Methods : From our patients' medical records, we retrieved 20 patients with IgAN, to whom renal biopsies had been performed for the initial diagnosis and follow-up to find out any histologic changes. Initial and follow-up biopsies were classified by Haas classification. The changes of these parameters were compared with the evolution of clinical features. Results : Patients were treated with angiotensin-converting enzyme inhibitors in combination with angiotensin receptor blockers (in subclass II or above) and short-term cyclosporine A(in patients showing nephrotic syndrome). Histologic improvement in 7 cases and deterioration in 3 cases were observed. At the time of last biopsy, 10 cases (50%) showed clinical remission and the others showed improved clinical features. These clinical outcomes did not correlate with initial Haas classifications. Hypertension at onset observed in 5 cases (25%) revealed significant correlation with clinical outcome (P =0.01) and last Haas classification (P =0.007). None of the cases showed progression to CRF or ESRD. Conclusion : During a mean follow-up of $10.8{\pm}3.4$ years, childhood IgAN showed good clinicopathologic outcome. Hypertension at onset was only a strong predictor of clinicopathologic outcomes, but initial Haas classification cannot predict outcomes in children. Histologic change of IgAN in long term follow-up period cannot be completely predicted by clinical data and vice versa. Therefore, a renal biopsy should be considered as a part of follow-up plan.