한국형 인공심장 내의 혈류에 대한 수치해석적 연구

심은보,박명수,여종영,고형종,박찬영,민병구 제주대학교 인공심장이식연구소 2001 인공심장 연구 Vol.2 No.1

한국형 인공심장 내의 혈액 유동을 유한요소 코드인 ADINA를 사용하여 수치적으로 조사하였다. 그 동안 많은 실험을 통해서 밝혀진 중요한 문제점들 중의 하나는 바로 혈전 생성이다. 이것은 혈액 주머니내의 작용하는 과도한 높은 전단응력 또는 정체 영역과 밀접한 관련이 있다. 한국형 인공심장 내의 혈류는 액추에이터와 혈액주머니, 그리고 혈액의 상호작용에 의하여 정의될 수 있다. 여기에서 혈액은 비압축성, 뉴우턴 유체로 가정하였으며, 혈액주머니는 등방성 선형 고체재질로 가정하였다. 2차원 모델은 액추에이터와 혈액 주머니 사이의 접측 문제 및 고체-유체 상호작용 문제를 전부 고려하였다. 3차원 모델에서는 액추에이터에 의한 변형을 접촉문제를 혈액주머니 외부에 작용하는 압력조건으로 단순화하였다. 2차원 모델 계산결과에 의하면, 입구 및 출구 부근, 그리고 모서리 부근에서 전단응력의 세기가 매우 크다는 것을 발견할 수 있었다. 또한 위쪽 돌출부에서 속도가 매우 느려지는 정체 영역이 형성되었으며, 이는 실험에서 관찰된 혈전 생성영역과 거의 일치한다. 3차원 계산의 경우에도 역시 입구와 출구 부분에서 재순환 영역이 발견되었으며, 수축시에는 입구의 아래쪽에서, 이완시에는 출구의 아래쪽에서 정체영역이 생성됨을 알 수 있었다. One of the crucial problems which make the artificial heart operate improperly is the thrombus formation. Many experimental results show the thrombus formation is strongly retated with a high shear stress and the stagnation in the blood flow. Therefore study on the blood flow in artificial hearts is very important in a practical point of view. This thesis deals with the two- and three-dimensional unsteady blood flows in the Korean total artificial hearts(KTAH). It is numerically investigated by using the commercial finite element code ADINA. The flow in the sac of artificial heart results from the mutual interaction of the acuator, sac, and blood. Blood is assumed as an incompressible viscous Newtonian fluid, while the sac is considered to be elastic and isotropic solid material. The contact problem between the actuator and sac is included in the two-dimensional modelling. Because of the tremendously calculation time, the action of the actuator is replaced by the imposition of the time-varying pressure on the outer surface of the sac. Numerical results show a high shear stress distribution near the inlet and outlet corners of the sac. From two-dimensional calculation flow stagnation is seen to be found in the upper convex part of the sac. By comparing the numerical results with the experimental ones we can conclude the thrombus is generated in regions where blood flow stagnates or is very slow.

관상동맥질환 환자에서 스텐트 시술 후 재협착에 관한 연구

강진환,권영주,박상호,한대희,이상철,김명구,변정득,최병조,심규혁,온영근,현민수,김성구 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background and aims : In the coronary artery disease, a rate of restenosis was much decreased by placement of coronary stent than when percutaneous transluminal coronary angioplasty has been applied, but there are still important clinical problems of restenosis. There has been many progressive studies about various factors contributed to this restenosis. So, we studied a relation between restenosis after placement of coronary stent in the coronary artery disease and many clinical factors, characteristics of stenotic lesion and procedural factors, and also assessed the restenosis rate of various coronary stents. Methods : Total 58 lesions(46 cases of patients ; man 30, woman 16) were evaluated, which has been performed a follow-up coronary angiography after 6 months (mean 188 days) since coronary stent had been placed. Various stents were implanted and assessed a relation between restenosis and many factors. Results : Of 58 lesions were target stenotic studies, there were 22 of restenotic lesions(37.9%), and the restenosis rate wes statistically significant difference in the relation with diabetes mellitus(p<0.05), group of acute myocardial infarction(p<0.05) among clinical diagnosis of ischemic heart disease(stable angina, unstable angina and acute myocardial infarction) in clinical factors and with high dilation pressure of stent(p<0.05) in procedural factors. When the rate of restenosis was evaluated among implanted stents, it was lowest in the Multilink^(®) stent and highest in the Nir Royal^(®) stent(60%). Conclusion : In this study of restenosis and various factors after placement of stents in the coronary artety disease, factors such as diabetes mellitus, group of acute myocardial infarction and a dilation pressure of stent were significant related with restenosis and the restenosis rate of Multilink^(®) stent was lowest and the highest restenosis rate was of Nir Royal^(®) stent.

허혈성 심질환에서 염증지표에 관한 연구

번정득,권영주,박상호,한대희,이상철,강진환,김명구,심규혁,최병조,온영근,현민수,김성구 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background : Atherosclerosis is the chief underlying cause of ischemic heart disease and there is increasing evidence that inflammation is an important determinant of the development of atherosclerosis. We assessed the levels of inflammatory markers in patients with ischemic heart disease and normal group who has normal coronary angiograms. Materials and Methods : Coronary angiography was performed in 142 patients. 107 patients of ischemic heart disease(stable angina pectoris 58, unstable angina pectoris 30, Acute myocardial infarction 19) and 38 normal control subjects. We assessed the level of inflammatory markers, such as CRP, ESR, fibrinogen and leukocyte. Results : CRP, ESR and fibrinogen values of the patients with stable angina pectoris and unstable angina pectoris were higher than that of normal control group, but there were no statistical significance. Leukocyte value of the patients with unstable angina pectoris(9003.3±701.5/mm^(3)) was significantly higher than that of the patients with stable angina pectoris(6685.5±245.8/mm^(3)) and normal control subjects(6394.3±235.1/mm^(3)). CRP, ESR and fibrinogen values of the patients with acute myocardial infarction were also higher than that of normal control subjects. CRP was 3.88±2.05 mg/dL in acute mocardial infarction group, and 0.29±0.15 mg/dL in normal control subject group(p<0.05). Fibrinogen was 541.6±45.1 mg/dL in acute myocardial infarction group, 321.4±25.6 mg/dL in normal control subject group(p<0.05). Leukocyte was 10942.1±737.6/mm^(3) in acute myocardial infarction group, 6394.3±235.1/mm^(3) in normal control subject group(p<0.05). Conclusions : This study demonstrate that CRP, fibrinogen and leukocyte values of acute myocardial infarction group were significantly higher than that of control group and stable, unstable argina pectoris group. Leucokyte values were significantly elevated in unstable angina group, but CRP values were not in unstable angina group.

만성 심부전환자의 혈액에서 측정한 Tumor necrosis factor-α 및 Interleukin-6의 임상적 의의

김명구,김성구,박상호,한대희,강진환,변정득,심규혁,최병조,방덕원,온영근,현민수,권영주 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background and objectives: Many conditions are responsible for the pathophysiology and progressive mechanisms of congestive heart failure. More recently, it has also become evidence that another class of biologycally activated molecules generically reffered to as cytokine these are also over expressed in congestive heart failure. Therefore, the purpose of this study was to measure concentrations of tumor necrosis factor-α(TNF-α), interleukin-6(IL-6) in mild to severe symptoms of heart failure and compare their values with those found in normal control and analysed correlation relationship between cytokine level, clinical findings and hemodynamic indicies. Subjects and Methodology: Levels of TNF-α and IL-6 were measured on pulmonary artery during cardiac catheterization in heart failure patients(n=32) and normal subjects(n=8) as well as physical examination and echocardiogram. Cytokines assay were performed on plasma using commercially available ELISA(Enazyme-Linked Immunosorbent Assay) kits. Results: Although the levels of TNF-α and IL-6 tend to increase in congestive heart failure group, the cytokines level was not made significantly statistical difference between congestive heart failure group and controls. When analyzing the correlation between the levels of PCWP(pulmonary capillary wedge pressure) and cytokines(TNF-α, IL-6), respectively, there were statistically significant correlation coefficient 0.32,(p<0.05), 0.39(p<0.01). The cytokine IL-6 and pressure of pulmonary artery were significant correlation.(correlation coefficient 0.36, p<0.02) More significantly, there was correlated with TNF-α and IL-6.(correlation coefficient 0.57, p<0.001) Conclusions: There was tended toward high concentration of TNF-α & IL-6 in congestive heart failure and significant difference for PCWP between TNF-α & IL-6, thus may be correlated with development and progression in congestive heart failure.

High dose Chemotherapy and Autologous Stem Cell Transplantation for Poor Risk and Recurrent Non-Hodpkin`s Lymphoma: A Single-Center Experience of 50 Patients

( Byoung Yong Shim ),( Myoung A Lee ),( Jae Ho Byun ),( Sang Young Roh ),( Chi Won Song ),( Jin No Park ),( Jong Wook Lee ),( Woo Sung Min ),( Young Seon Hong ),( Chun Choo Kim ) 대한내과학회 2004 The Korean Journal of Internal Medicine Vol.19 No.2

Patent foramen ovale: diagnosis with multidetector CT--comparison with transesophageal echocardiography.

Kim, Young Jin,Hur, Jin,Shim, Chi-Young,Lee, Hye-Jeong,Ha, Jong-Won,Choe, Kyu Ok,Heo, Ji Hoe,Choi, Eui-Young,Choi, Byoung Wook Radiological Society of North America 2009 Radiology Vol.250 No.1

<P>PURPOSE: To evaluate the clinical feasibility and accuracy of 64-section multidetector computed tomography (CT) compared with transesophageal echocardiography (TEE) for diagnosis of a patent foramen ovale (PFO). MATERIALS AND METHODS: Institutional review board approval was obtained for this retrospective study. The study included 152 consecutive stroke patients (mean age, 61.7 years; 98 men, 54 women) who underwent both cardiac multidetector CT and TEE. Electrocardiographically gated cardiac CT was performed with a 64-section CT scanner by using a saline-chaser contrast agent injection technique. A contrast agent jet from the contrast agent-filled left atrium (LA) to the saline-filled right atrium (RA) and channel-like appearance of the interatrial septum (IAS) were evaluated on axial and oblique sagittal CT images. Two-dimensional and Doppler TEE were performed to detect PFO. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT were obtained with TEE as the reference standard. RESULTS: A PFO was present in 26 patients at TEE. On CT images, a left-to-right contrast agent jet toward the inferior vena cava was noted in 21 patients (sensitivity, 73.1%; specificity, 98.4%; PPV, 90.5%; NPV, 94.7%). Channel-like appearance of the IAS was detected in 38 patients (sensitivity, 76.9%; specificity, 85.7%; PPV, 52.6%; NPV, 94.7%). Channel-like appearance of the IAS was noted in all patients who had a contrast agent jet. CONCLUSION: A contrast agent jet from LA to RA toward the inferior vena cava with channel-like appearance of the IAS on CT images confirms the presence of a PFO.</P>

흡연이 폐환기능에 미치는 급성효과에 관한 연구

이영현 ( Young Hyun Lee ),이명혜 ( Myung Hye Lee ),최병휘 ( Byoung Whyui Choi ),박춘식 ( Chun Sik Park ),심영수 ( Young Soo Shim ),김건열 ( Keun Youl Kim ),한용철 ( Young Chul Han ) 대한결핵 및 호흡기학회 1982 Tuberculosis and Respiratory Diseases Vol.29 No.4

Patterns of late gadolinium enhancement are associated with ventricular stiffness in patients with advanced non-ischaemic dilated cardiomyopathy.

Choi, Eui-Young,Choi, Byoung Wook,Kim, Sung-Ai,Rhee, Sang Jae,Shim, Chi Young,Kim, Young Jin,Kang, Seok-Min,Ha, Jong-Won,Chung, Namsik Elsevier Science 2009 European journal of heart failure Vol.11 No.6

<P>AIMS: Despite the prognostic importance of ventricular filling and ventricular-arterial interaction in patients with advanced systolic heart failure, the structural determinants of these parameters have not been fully studied. We aimed to investigate whether patterns of late gadolinium enhancement (LGE) on cardiac magnetic resonance affect ventricular elastic properties or performance in patients with non-ischaemic dilated cardiomyopathy (DCM). METHODS AND RESULTS: Patients (n = 49) with markedly reduced systolic function (left ventricular (LV) ejection fraction <35%) due to longstanding non-ischaemic DCM underwent contrast-enhanced cardiac magnetic resonance after comprehensive echo-Doppler evaluations. The single beat-derived end-diastolic elastance, end-systolic elastance, arterial elastance, and dyssynchrony indices were measured by echo. On the basis of LGE patterns, patients could be divided into three groups: non-LGE (n = 18), non-midwall LGE (n = 13), and midwall LGE (n = 18). The midwall LGE group had lower LV systolic longitudinal velocity (4.6 +/- 1.7 for non-LGE vs. 4.3 +/- 1.2 for non-midwall LGE vs. 3.5 +/- 1.0 cm/s for midwall LGE, P = 0.025), higher end-diastolic elastance index (0.41 +/- 0.21 vs. 0.46 +/- 0.31 vs. 0.85 +/- 0.51 respectively, P = 0.008), and a more impaired ventriculoarterial coupling index (3.14 +/- 1.53 vs. 2.88 +/- 1.94 vs. 5.52 +/- 3.18, P = 0.006) than other subgroups. CONCLUSION: Patients with midwall LGE had a higher ventricular stiffness index and more impaired ventriculoarterial coupling when compared with other non-ischaemic DCM patients.</P>

Reference Values of Impulse Oscillometry and Its Utility in the Diagnosis of Asthma in Young Korean Children

Lee, Jung-Yong,Seo, Ju-Hee,Kim, Hyung Young,Jung, Young Ho,Kwon, Ji-Won,Kim, Byoung-Ju,Kim, Hyo Bin,Lee, So-Yeon,Jang, Gwang Cheon,Song, Dae Jin,Kim, Woo Kyung,Shim, Jung Yeon,Kim, Ha-Jung,Shin, Yee-J Informa Healthcare 2012 The Journal of asthma Vol.49 No.8

<P><I>Aims</I>. The aims of this study were (1) to determine the reference values for impulse oscillometry (IOS) and (2) to apply them to the evaluation of asthma in the general population of young Korean children. <I>Methods</I>. We performed a questionnaire survey and IOS measurements in 390 children aged 3-7 years in Seoul and Gyeonggi province, Korea, from July to August 2010. IOS measurements included respiratory resistance (Rrs) and respiratory reactance (Xrs) at 5, 10, 15, 20, 25, and 35 Hz, respiratory impedance (Zrs), and resonance frequency (RF) before and 15 min after inhalation of 200 μg salbutamol. To determine the reference values for IOS, 161 children defined as healthy controls were assessed. <I>Results</I>. The IOS measurements were presented as means and standard deviations. The reference equations for IOS variables were determined by multiple linear regression analysis taking into account their height, weight, and age (R5 = 2.242 - 0.008 × height (cm) - 0.005 × age (months), coefficients of determination (<I>R</I><SUP>2</SUP>) = 0.213). Height had the greatest correlation with IOS variables, similar to previous studies. Positive airway obstruction was defined as R5 greater than the 95th percentile of predicted R5 from the reference equation. There was a higher percentage of children with positive airway obstruction in children with asthma than in healthy controls (27.3% vs. 6.2%). Multivariate logistic regression analysis indicated that positive airway obstruction was a significant risk factor for the diagnosis of asthma (adjusted odds ratio (aOR), 6.245; 95% confidence interval (CI), 2.270-17.175). <I>Conclusion</I>. This study provided reference values for IOS in young Korean children and applied the reference values to evaluate children with asthma. We suggest the 95th percentile of predicted R5 as a cut-off value for positive airway obstruction, which may increase the risk for diagnosis of asthma.</P>

A Study on Visual Feedback Control of Industrial Articulated Robot

Byoung-Kyun Shim(심병균),Woo-Song Lee(이우송),In-Man Park(박인만),Won-Jun hwang(황원준),Young-Sik Choi(최영식) 한국산업융합학회 2014 한국산업융합학회 논문집 Vol.17 No.1

This paper proposes a new approach to the designed of visual feedback control system based on visual servoing method. The main focus of this paper is presented how it is effective to use many features for improving the accuracy of the visual feedback control of industrial articulated robot for assembling and inspection of parts. Some rank conditions, which relate the image Jacobian, and the control performance are derived. It is also proven that the accuracy is improved by increasing the number of features. The effectiveness of redundant features is verified by the real time experiments on a SCARA type robot(FARA) made in samsung electronics company.