관상동맥 스텐트 시술 후의 재협착에 관한 연구

김윤철,이정우,김보영,강정아,임대승,이민수,김정희,성보영,최성준,성인환,전은석 충남대학교 의과대학 지역사회의학연구소 2000 충남의대잡지 Vol.27 No.1

Coronary stent implacement is known as an effective treatment in the intimal dissection after percutaneous transluminal coronary angioplasty and the prevention of restenosis. However, In-stent restenosis still remains a major concern in clinical stenting. The stents were placed in 103 patients from July 1996 to March 1999 and performed follow-up coronary angiograms in 59(57.3%) patients. To identify the clinical, angiographic and procedurerelated variables 'which predict late restenosis within the stented artery, 59 patients(58.3±9.9, M:F= 41:18) were studied. The clinical characteristics of the patients were stable angina in 23(39.0%), unstable angina in 14(23.7%), acute myocardial infarction in 21(35.6%) and old myocardial infarction in 1(1.7%). Coronary stenting was performed in 1 patient(1.7%) for primary lesion, 50 patients(84.7%) for suboptimal results after PTCA, 6 patients(10.2%) for bail-out procedure, and 2 patients(3.4%) for restenotic lesions. All patients were treated with aspirin and ticlopidinc. The follow-up angiograms were obtained at 7±4 months. The overall in-stent restenosis rate was 27.1%. The coronary angiographic findings were 32 single vessel(54.2%), 19 two vessel(32.2%) and 8 three vessel disease(13.6%). The angiographic morphological characteristics were type A in 33(55.9%), type B in 14(23.7%), type C in 12(20. 3%) cases. Variables of 16 patients with restenosis were compared with those of 43 patients without restenosis. Previously known predictors for in-stent restenosis were multiple stenting, stenting for restenotic lesions, residual stenosis after stenting, stenting for total occlusion lesions, reference diameter, balloon to vessel ratio, acute gain and minimal luminal diameter after procedure, design and characteristics of stents, ostial lesion of aorta, high pressure method for stenting, lesion length, diabetes mellitus, size of artheroma, saphenous vein grafts, ulcerlating lesions and calcified lesions. In this study, Reference diameter before stenting(2.43±0.54mm vs. 2.88±0.65mm, p=0.016) and balloon-to-artery ratio(1.28±0.26 vs. 1.11±0.18, p=0.006) were predictors for in-stent restenosis. 1) The overall in-stent restenosis rate was 27.1%. 2) In the analysis of predictors for in-stent restenosis, there was no significant differences in clinical, angiographic factors between group with restenosis and without restenosis. But, Only reference diameter before stenting and balloon-toartery ratio were predictors of late in-stent restenosis. In conclusion, stenting is effective revascularisation method for selected patients with ischemic heart disease, and to minimize in-stent restenosis rate, stent implanting is achieved in a large vessel on the basis of an artery-to-stnet ration of 1:1, if possible.

스탬핑 성형해석을 위한 유한요소의 자동생성

유동진,윤정환 대진대학교 생산기술연구소 1999 생산기술연구소 논문집 Vol.2 No.-

In the present study, a general method for the mathematical description of arbitrarily shaped surface is proposed by introducing the parametric surface. A polynomial function is employed to descrive the base parametric surface and the boundary curves are defined to describe arbitrary three - dimensional trimmed surfaces. For the mesh generation of initial sheet blank, a grid-based mesh generation algorithm using quadtree is proposed. In order to generate the finite element mesh for tool surface, a hybrid method based on the grid approach and the Delaunay triangulation if proposed. To verify the validity of the proposed method, automatic mesh generation is carried out for some chosen complicated parts including actral automotive panel.

Modeling of Directional Hardening Based on Non- Associated Flow for Sheet Forming

Jeong Whan Yoon,Thomas B. Stoughton 한국소성가공학회 2010 기타자료 Vol.2010 No.6

This work describes a material model for sheet metal forming that takes into account anisotropic hardening under conditions of proportional loading. Conventional isotropic and kinematic hardening models constrain the shape of the yield function to remain fixed throughout plastic deformation, which is not consistent with most test data from aluminum alloys obtained under proportional loading. Conventional hardening models are shown to introduce systemic errors in stresses in different loading conditions at low and high levels of strain that tend to amplify the effect of stress miscalculation on the prediction of springback. A new model is described in which four stress-strain functions are explicitly integrated into the yield criterion in closed form solution. The model is based on non-associated flow so that this integration does not affect the accuracy of the plastic strain components. The model is expected to lead to a significant improvement in stress prediction under conditions dominated by proportional loading, and this is expected to directly improve the accuracy of springback prediction for these processes.

Involvement of Endoplasmic Reticulum Stress Response in the Neuronal Differentiation

Yoon Mi Cho,Yoon Seong Jang,Young-Min Jang,Jin-Young Seo,Ho Shik Kim,Jeong Hwa Lee,Seong Whan Jeong,In Kyung Kim,Oh-Joo Kwon 대한생리학회-대한약리학회 2007 The Korean Journal of Physiology & Pharmacology Vol.11 No.6

Expressions of endoplasmic reticulum stress response (ERSR) genes were examined during the neuronal differentiation of rat fetal cortical precursor cells (rCPC) and rat pheochromocytoma PC12 cells. When rCPC were differentiated into neuronal cells for 7 days, early stem cell marker, nestin, expression was decreased from day 4, and neuronal markers such as neurofilament-L, -M and Tuj1 were increased after day 4. In this condition, expressions of BIP, ATF6, and phosphorylated PERK as well as their down stream signaling molecules such as CHOP, ATF4, XBP1, GADD34, Nrf2 and p58<SUP>IPK</SUP> were significantly increased, suggesting the induction of ERSR during neuronal differentiation of rCPC. ERSR was also induced during the differentiation of PC12 cells for 9 days with NGF. Neurofilament-L transcript was time-dependently increased. Both mRNA and protein levels of Tuj1 were increased after the induction, and the significant increase in NeuN was observed at day 9. Similar to the expression patterns of neuronal markers, BIP/GRP78 and CHOP mRNAs were highly increased at day 9, and ATF4 mRNA was also increased from day 7. These results strongly suggest the induction and possible role of ERSR in neuronal differentiation process. Further study to identify targets responsible for neuronal induction will be necessary.

Solution Dynamics Studies for the Lck SH2 Domain Complexed with Peptide and Peptide-Free Forms

(Jeong Hyeok Yoon),(Myung Whan Chi),(Chang No Yoon),(Jong Sei Park) 한국응용약물학회 1995 학술대회 Vol.1995 No.1

알루미늄 판재성형을 위한 구성 방정식과 파단 모델

윤정환(Yoon, Jeong Whan) 한국소성가공학회 2018 박판성형 심포지엄 Vol.2018 No.3

∙ Constitutive Models should consider both r-value and stress directionalities for accurate prediction of anisotropy. ∙ PEPS diagram can correct the offset from nonlinear strain path in forming limit and can be applied for surface crack. ∙ Stress-based forming limit and fracture model can be successfully used for general fracture applications. ∙ Mean stress contribution in M-C model gives very good correlation with observed experimental data.

직접설계법에 의한 박판부품의 초기형상설계

윤정환(Jeong-Whan Yoon),김상국(Sang-Kook Kim),정관수(Kwansoo Chung),연의정(Eui-Jung Yeon) 한국소성가공학회 2000 박판성형 심포지엄 Vol.2000 No.8

Involvement of Endoplasmic Reticulum Stress Response in the Neuronal Differentiation

Cho, Yoon-Mi,Jang, Yoon-Seong,Jang, Young-Min,Seo, Jin-Young,Kim, Ho-Shik,Lee, Jeong-Hwa,Jeong, Seong-Whan,Kim, In-Kyung,Kwon, Oh-Joo The Korean Society of Pharmacology 2007 The Korean Journal of Physiology & Pharmacology Vol.11 No.6

Expressions of endoplasmic reticulum stress response (ERSR) genes were examined during the neuronal differentiation of rat fetal cortical precursor cells (rCPC) and rat pheochromocytoma PC12 cells. When rCPC were differentiated into neuronal cells for 7 days, early stem cell marker, nest in, expression was decreased from day 4, and neuronal markers such as neurofilament-L, -M and Tuj1 were increased after day 4. In this condition, expressions of BIP, ATF6, and phosphorylated PERK as well as their down stream signaling molecules such as CHOP, ATF4, XBP1, GADD34, Nrf2 and $p58^{IPK}$ were significantly increased, suggesting the induction of ERSR during neuronal differentiation of rCPC. ERSR was also induced during the differentiation of PC12 cells for 9 days with NGF. Neurofilament-L transcript was time-dependently increased. Both mRNA and protein levels of Tuj1 were increased after the induction, and the significant increase in NeuN was observed at day 9. Similar to the expression patterns of neuronal markers, BIP/GRP78 and CHOP mRNAs were highly increased at day 9, and ATF4 mRNA was also increased from day 7. These results strongly suggest the induction and possible role of ERSR in neuronal differentiation process. Further study to identify targets responsible for neuronal induction will be necessary.

Effects of vitamin D supplements in patients with chronic hepatitis C: a randomized, multi-center, open label study

Jae Yoon Jeong,Dae Won Jun,Sol Ji Park,Joo Hyun Sohn,Sang Gyune Kim,Se Whan Lee,Soung Won Jeong,Moon Young Kim,Won Kim,심재준,김형수,석기태,Sang Bong Ahn 대한내과학회 2020 The Korean Journal of Internal Medicine Vol.35 No.5

Background/Aims: We aimed to assess the role of vitamin D supplementation in the response to pegylated interferon-α (PEG-IFN-α) plus ribavirin (RBV) treatment in patients with chronic hepatitis C (CHC). Methods: Our study was a multi-center, randomized controlled trial in 11 hospitals. CHC patients were randomly assigned (1:1) to two groups namely, PEGIFN-α plus RBV (control group) or PEG-IFN-α plus RBV + vitamin D (800 IU daily) (vitamin D group). The primary end-point was the rate of sustained virologic response (SVR). Results: One hundred forty eight CHC patients were randomly assigned to two groups. Seventy-one patients received the PEG-IFN-α plus RBV and 77 patients received the PEG-IFN-α plus RBV + vitamin D. A total of 105 patients completed the study (control group, 47 vs. vitamin D group, 58). Baseline characteristics were mostly similar in both the groups. There was a modest but non-significant increase in SVR in the vitamin D group compared to the control group with the intention to treat analysis (64.0% vs. 49.3 %, p = 0.071) as well as in the per protocol analysis (control group vs. vitamin D group: 74.5% vs. 84.5%, p = 0.202). Fifty-two patients (73.2%) in the control group and 63 patients (81.8%) in the vitamin D group experienced at least one adverse event. The drop-out rate due to adverse effects was not different between both groups (control group vs. vitamin D group: 19.7% vs. 10.4%, p = 0.111). Conclusions: Vitamin D supplement did not increase SVR in treatment naïve patients with CHC irrespective of genotype.

Optimal Duration of Dual Antiplatelet Therapy After Drug-Eluting Stent Implantation : A Randomized, Controlled Trial

Lee, Cheol Whan,Ahn, Jung-Min,Park, Duk-Woo,Kang, Soo-Jin,Lee, Seung-Whan,Kim, Young-Hak,Park, Seong-Wook,Han, Seungbong,Lee, Sang-Gon,Seong, In-Whan,Rha, Seung-Woon,Jeong, Myung-Ho,Lim, Do-Sun,Yoon, American Heart Association, Inc. 2014 CIRCULATION - Vol.129 No.3

<P><B>Background—</B></P><P>The risks and benefits of long-term dual antiplatelet therapy remain unclear.</P><P><B>Methods and Results—</B></P><P>This prospective, multicenter, open-label, randomized comparison trial was conducted in 24 clinical centers in Korea. In total, 5045 patients who received drug-eluting stents and were free of major adverse cardiovascular events and major bleeding for at least 12 months after stent placement were enrolled between July 2007 and July 2011. Patients were randomized to receive aspirin alone (n=2514) or clopidogrel plus aspirin (n=2531). The primary end point was a composite of death resulting from cardiac causes, myocardial infarction, or stroke 24 months after randomization. At 24 months, the primary end point occurred in 57 aspirin-alone group patients (2.4%) and 61 dual-therapy group patients (2.6%; hazard ratio, 0.94; 95% confidence interval, 0.66–1.35; <I>P</I>=0.75). The 2 groups did not differ significantly in terms of the individual risks of death resulting from any cause, myocardial infarction, stent thrombosis, or stroke. Major bleeding occurred in 24 (1.1%) and 34 (1.4%) of the aspirin-alone group and dual-therapy group patients, respectively (hazard ratio, 0.71; 95% confidence interval, 0.42–1.20; <I>P</I>=0.20).</P><P><B>Conclusions—</B></P><P>Among patients who were on 12-month dual antiplatelet therapy without complications, an additional 24 months of dual antiplatelet therapy versus aspirin alone did not reduce the risk of the composite end point of death from cardiac causes, myocardial infarction, or stroke.</P><P><B>Clinical Trial Registration—</B></P><P>URL: http://www.clinicaltrials.gov. Unique identifier: NCT01186146.</P>