• Journal of Yeungnam Medical Science
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• v.5 no.2
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• pp.59-69
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• 1988

This study was designed to investigate the effect of substitution of strontium for calcium on mechanical activity in isolated perfused spontaneously beating rat hearts. The mechanical activity of the hearts of Langendorff's preparation in conditions of low calcium and strontium-substitution for calcium was compared. The effect of norepinephrine and verapamil were also observed in those conditions. The results were as follows : 1. In low calcium, the mechanical activity of the heart preparation was significantly reduced, but when the equimolar strontium was substituted for the reduced calcium, the activity was kept at similar level to the normal condition. 2. When equimolar strontium was substituted for the total calcium in perfusate, the heart preparation stopped its beating, and it was not restored in spite of reperfusion with normal calcium perfusate. 3. Norepinephrine-induced positive inotropic effect was inhibited in low-calcium condition especially with low concentration of norepinephrine, but not in strontium-substitution for calcium. 4. Verapamil reduced the activity of the heart both in low-calcium and strontium-substitution as well as in normal calcium conditions. From above results, it was concluded that strontium served as a substitute of calcium in maintaining mechanical activity and in responsiveness to norepinephrine, and the influx of strontium through cell membrane is inhibited by verapamil as the influx of calcium.

• The Korean Journal of Nuclear Medicine
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• v.34 no.3
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• pp.228-233
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• 2000

Purpose: The aim of this study is to better understand the pattern and nature of reverse redistribution (RR) in myocardial perfusion imaging. Materials and Methods: In consecutive 20 acute myocardial infarction (MI) patients, frequency of RR was correlated with that of subendocardial MI that was detected by myocardial contrast echocardiography (MCE). RR was judged to be present when there was more than one grade of worsening in perfusion at 24 hr delayed images compared with the initial rest images. MCE evaluated the significant lack of opacification in the subendocardial myocardium relative to the subepicardial myocardium to suggest the subendocardial MI. Kendall's nonparametric correlation coefficiency was calculated. Results: Concordant cases were 15 of 20 (75%) and correlation was statistically significant (p=0.0285). Conclusion: Our results suggested that RR was correlated with MCE-detected nontransmural MI.

• Journal of Chest Surgery
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• v.35 no.5
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• pp.336-342
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• 2002

Background: Recently, cell transplantation has been extensively investigated to improve heart function in dysfunctional heart. This study was designed to compare the effects of smooth muscle cells (SMC) and heart cells (HC) transplantation in dilated cardiomyopathic hamsters. Material and Method: HC and SMC were isolated from heart and ductus deferens of BIO 53.58 hamsters, and cultured for transplantation. HC and SMC or culture medium were transplanted into the left ventricle of 17 weeks old adult hamsters in HC transplanted (HCTx), SMC transplantation (SMCTX), and control groups (Con) (N = 10 each). Cyclosporine (5 mg/Kg) was administered subcutaneously for HCTx. Sham operated hamsters (N=10) underwent the surgery but did not receive an injection. At 4 weeks after transplantation, heart function was evaluated in all groups using a Langendorff perfusion apparatus. Result: Histology showed severe focal myocardial necrosis in all groups. HCTx and SMCTx formed huge muscle tissue in dilated myocardium. SMCTx and HCTx had better heart function than Con and sham (p<0.01). And SMCTx had better peak systolic pressure (p<0.05) antral developed pressure (p<0.05) than HCTx. But sham and Con did not any statistical make difference. Conclusion: SMCTx and HCTx formed muscle tissue and improved ventricular function in hamsters with dilated cardiomyopathy And SMCTx showed better heart function in peak systolic pressure and developed pressure than HCTx.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.4
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• pp.291-298
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• 2007

Purpose: To investigate the feasibility of TI-201 SPECT with intra coronary injection (lC-I) in the detection of viable myocardium, we have performed SPECT imaging after direct intracoronary injection of TI-201 and images were compared with those of stress-reinjection (Re-I) SPECT. Methods: Fourteen coronary artery disease patients (male 11, mean age 54 years) who had myocardial infarction or demonstrated left ventricular wall motion abnormality on echocardiography were enrolled. Three mCi of TI-201 was injected into both coronary arteries during angiography and images were acquired between 6- and 24-hour after injection. Reinjection imaging with 1 mCi of TI-201 was performed at 4-hour after adenosine stress imaging with 3 mCi of TI-201. Images were interpreted according to 4-grade visual scoring system (grade 0-3). Segments with mild to moderated uptake (${\leq}$grade 1), and upgraded more than one score with reinjection, and were defined as viable myocardium. Results: Image quality was poor in two cases with IC-I. Numbers of non-viable segments were 60 (23.8%) with IC-I, and 38 (15.1%) with Re-I, respectively. Overall agreement for perfusion grade per myocardial segment in each IC-I and Re-I was 76.5%. Overall agreement for viable segment between IC-I and Re-I was 90.5%. Only one out of 38 segments interpreted as non-viable with Re-I were interpretated as viable with IC-I. And 23 out of 214 segments interpreted as viable with Re-I were interpreted as non-viable with IC-I. Conclusion: Intracoronary TI-201 SPECT seemed to be not advantageous over stress-rest reinjection imaging in the assessment of myocardial viability, mainly due to low count statistics at 6-hour or 24-hour delayed time points. The feasibility of intracoronary TI- 201 SPECT is considered to be limited.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.223-230
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• 1995

This study investigates a combined mathematical model for the quantitative estimation of regional myocardial blood flow in experimental canine coronary artery occlusion and in patients with ischemic myocardial diseases using Rb-82 dynamic myocardial positron emission tomography. The coronary thrombosis was induced using the new catheter technique by narrowing the lumen of coronary vessel gradually, which finally led to partial obstruction of coronary artery. Thirty four Rb-82 dynamic myocardial PET scans were performed sequentially for each experiment using our 5, 10 and 20 second acquisition protocol, respectively, and six to seven regions of interest were drawn on each transaxial slices, one on left ventricular chamber for input function and the others on normal and decreased perfusion myocardial segments for the flow estimation in those regions. Two compartment model and graphical analysis method have been applied to the measured sets of regional PET data, and the rate constants of influx to myocardial tissue were calculated for regional myocardial flow estimates with the two parameter fits of raw data by the Levenberg-Marquardt method. The results showed that, (I) two compartment model suggested by Kety-Schmidt, with proper modification of the measured data and volume of distribution, could be used for the simple estimation of regional myocardial blood flow, (2) the calculated regional myocardial blood flow estimates were dependent on the selection of input function, which reflected partial volume effect and left ventricular wall motion in previously used graphical analysis, and (3) mathematically fitted input and tissue time activity curves were more suitable than the direct application of the measured data in terms of convergence.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2223-2230
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• 2011

ECG is used to diagnose heart diseases such as myocardial ischemia, arrhythmia and myocardial infarction. Particularly, myocardial ischemia causes the shape change of the ST segment, this change is transient and may occur without symptoms. So it is important to detect the transient change of ST segment through long term monitoring. ST segment classification algorithm for making diagnosis myocardial ischemia is presented in this paper. The first step in the ST segment shape classification process is to detect R wave point and feature points based adaptive threshold and window. And then, the suggested algorithm detects the ST level change, To classify the ST segment shape, the suggested algorithm uses the slope values of the four points between the S and T wave. The ECG data in the European ST-T database were used to verify the performance of the developed algorithm. The best correct rate was 99.40% and the worst correct rate was 68.48%.

• Journal of Chest Surgery
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• v.40 no.9
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• pp.629-632
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• 2007

Most myocardial bridgings are found incidentally without symptoms, but myocardial bridging may induce symptoms such as angina, myocardial infarction, and ventricular arrythmia. In a patient who has symptoms despite of proper medication, stent insertion, supra-arterial myotomy or coronary artery bypass grafting have been applied without a definite guideline of treatment. We report two surgical cases of myocardial bridging with a review of the literature.

• The Korean Journal of Zoology
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• v.35 no.3
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• pp.308-321
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• 1992

심근세포는 골격근 세포와 더불어 세포의 분화기작을 이해하기 위한 좋은 모델이라 할 수 있다. 본 연구에서는 심근세포의 배양중에 일어나는 심근 근원섬유형성과정에 대한 이해를 위하여 SDS- 및 two-dimensional gel electrophoresis와 immunofluorescent 및 immunoelectron microscopy를 수단으로 이를 검토하였다. 배양과정에서 나타나는 주요한 단백질 중에서 SDS-PAGE에 의해 209 kDa와 53 kDa 및 46 kDa band가 각각 막분획 및 세포질 분획 단백질에서 배양과정동안에 가장 현저한 양상을 보였다. 특히 배양 3일과 4일의 양상에서 뚜렷한 변화를 나타내어 이들의 OD 격은 배양 96시간에서의 막분획에서 0.38(209 kDa)와 0.52(53 kDa) 및 배양 72시간에서의 세포질 분획에서 0.34(46 kDa)로 각각 최고치를 나타내었다. 또한 이차원 전기영동상의 양상에서도 세포질 및 막분획 단백질의 전반적인 전개양상이 배양 96시간에서 가장 두드러짐으로써 결국 배양 72시간 및 96시간대에서 심근 모세포의 분화와 관련된 일련의 단백질 합성과정이 가장 활발하다는 것을 알 수 있었다. 배양중에 발현되는 actin에 대한 형광현미경적 분석에 의해, actin은 세포내에서 불균등하게 분포하였고 근원섬유가 형성되는 시기인 배양 96시간에 세포외곽부에서 나타나는 다소 강한 염색성을 관찰할 수 있었다. 심근세포의 근원섬유는 전자현미경 관찰에 의해 primitive forms로 배양 96시간에 출현함을 알 수 있었으며 이 시기의 근원섬유의 형태는 여러 구성대(A, H and M bands)가 미약하나 1대는 비교적 뚜렷하였다. 따라서 심근세포의 T근원섬유형성과정에서 관찰되는 뚜렷한 단백질양상의 변화와 근원섬유의 출현시기 및 구성과정간에는 중요한 관련성이 있으며 이러한 과정에서 actin은 세포질내에서 불균등한 분포를 나타낸다는 것을 알 수 있었다.

• Journal of the Korean Society of Radiology
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• v.81 no.2
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• pp.250-271
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• 2020

Assessment of myocardial ischemia in patients with stable angina is important in deciding whether to treat coronary artery disease and in predicting clinical outcome. The fractional flow reserve is a standard reference for the diagnosis of myocardial ischemia, but this procedure has limitations because of its invasiveness. Coronary computed tomography angiography (CCTA) is now an established tool in the anatomic diagnosis of coronary artery disease; however, there are limits to the diagnosis of hemodynamically important stenosis that causes myocardial ischemia. In order to address this problem, studies using quantification of coronary atherosclerotic plaques, myocardial perfusion, and noninvasive calculation of fractional flow reserve based on CCTA have been actively conducted and recognized for their diagnostic value. In this review, several imaging techniques of CCTA used to assess myocardial ischemia are described.

• 순환기질환의공학회:학술대회논문집
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• 2005.05a
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• pp.79-88
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• 2005