• 대한의용생체공학회:의공학회지
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• 제25권6호
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• pp.497-503
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• 2004

건강한 정상인의 복부대동맥과 장골동맥 분기관의 다이콤 의료 영상으로부터 구성된 혈관 모델을 대상으로 전산혈류해석을 수행하였다. 본 연구에서는 CT로 촬영한 혈관영상으로부터 단면영상을 읽고 각 단면의 경계 좌표를 매끄럽게 추출하는 프로그램을 개발하여 적응하였다. 해석용 3차원 메쉬 생성과 혈류해석은 상용프로그램을 사용하였다. 해석을 통해 얻어진 압력, 속도 및 유량 분포는 정상인의 생리학적 범위 내에 있었다. 초음파로 측정된 장골동맥 중심부의 심장 수축기 속도는 해석에 비해 20% 정도 작은 값을 보였으며 한 주기 동안 속도 변화의 경향은 유사하였다. 본 연구의 접근방법은 환자 개인의 실제 혈관 형상에 기반한 혈류해석으로서 좁아진 동맥 또는 시술 될 동맥에서의 압력, 속도값, 속도분포에 대한 정보를 제공한다. 이 결과는 의사로 하여금 환자의 혈류역학적 변수의 변화를 파악하게 하여 환자의 상태를 더 잘 이해하고 수술의 필요성을 판단하도록 도움을 줄 수 있으며 나아가 혈관 수술의 기초자료로 사용될 수 있을 것이다. 이 연구는 향후 동맥경화와 밀접히 연관된 혈류역학적 변수의 분포를 혈관 내에 보여줌으로서 동맥경화를 조기 진단하는 프로그램으로 발전할 것으로 기대된다.

• 대한한방내과학회지
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• 제22권2호
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• pp.199-205
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• 2001

Background and Purpose : Transcranial doppler ultrasonography(TCD) is a noninvasive and nonradioactive technique for evaluation of the hemodynamics in large cerebral vessels. Sahyangsohap-won(SS) has been considered to be effective for the treatment of various disease, especially cerebrovascular, cardiovascular, and psychosomatoform disorders. But, there is no study about the effect of SS on the cerebral hemodynamics in humans. The aim of this study was to assess the effect of SS on the changes in cerebral hemodynamics and the dose-dependant effect by using TCD. Subjects and Methods : 30 healthy subjects were randomly divided into three group: group 1 took no drug, group 2 took SS one pill, and group 3 took SS 2 pills. Changes in the mean blood flow velocity(MBFV) and pulsatility index(PI) in the middle cerebral artery were evaluated by means of TCD. We obtained hypercapnia with breath-holding and evaluated cerebrovascular reactivity with the breath-holding index(BHI). Systolic blood pressure(SBP), diastolic blood pressure(DBP), and heart rate(HR) were measured by means of ambulatory blood pressure monitoring. In group 2 and group 3, the evaluations were performed during the baseline and were repeated at 20, 40, and 60 minutes after SS administration. In group 1, the evaluation was performed at corresponding time intervals. Results : In mean values of MSFV, PI, SSP, DBP, and HR, no stastically significant differences were found between the 3 groups. However, BHI values were significantly lower in groups 2 and 3 than in group 1 at 40 minutes after SS administration(P<0.05, group 1 vs group 2, group 1 vs group 3 by post-hoc analysis: Scheffe's test) but in dose-dependant effect, there was no difference between group 2 and group 3. Conclusion : These results suggest that SS can decrease vascular resistance in cerebral small arteries or arterioles and enhance their distensibility. Further studies on larger numbers of subjects are needed to confirm these effects and the dose-dependant effects.

• Journal of Acupuncture Research
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• 제21권1호
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• pp.111-118
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• 2004

Background and purpose: Opposing-needling technique involves selecting acupoints at unaffected limb. The aim of this study was to evaluate the effect of LI4-LI11 electrical acupuncture at unaffected limb on the cerebral blood flow in ischemic stroke patients using SPECT Methods: We selected 9 ischemic stroke patients. Baseline brain SPECT was done with triple head gamma camera(MultiSPECT3, Siemens, USA) after intravenous administration of 925 MBq of Tc-99m ECD). Fifteen-minute electro-acupuncture at Hapgok(LI 4) and Gokji(LI 11) were applied on unaffected upper limb of subjects. The same dose of Tc-99m ECD was injected during the electro-acupuncture, and the second SPECT images were obtained. Using the computer software(ICON 7.1, Siemens, USA), 3 SPECT slices(upper, middle, lower) surrounding the brain lesion were selected and each slice was divided by 10-16 brain regions. Asymmetry indexes were analyzed in each brain region. We regarded$\geq$10% changes of asymmetry index between before and after electro-acupuncture as significance. Results: Seven Patients(77.8%) had significantly increased perfusion and 2(22.2%) didn't show increased perfusion in post-acupuncture scans compared to pre-acupuncture scans(baseline). The regions of CBF improvement were mostly frontal lobes and anterior temporal lobes. Conclusions: This study demonstrated that LI4-LI11 electro-acupuncture at unaffected limb increased regional cerebral blood perfusion to the corresponding brain areas in ischemic stroke patients.

• Journal of Chest Surgery
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• 제37권4호
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• pp.342-348
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• 2004

말기 신부전 환자의 생명 유지를 위한 혈액투석 치료에 있어서 지속적으로 개존상태가 유지되고 충분한 혈액이 관류되는 투석 경로의 확보는 매우 중요하다. 동정맥루 조성술 시행 후 조기 폐쇄로 인해 투석을 시행하지 못하는 경우, 환자는 경정맥 또는 대퇴정맥 등의 중심 정맥 삽관을 반복적으로 시행 받아 혈액투석을 유지해야 하며 경제적, 시간적 손실을 감수해야 하는 어려움을 겪게 된다. 대상 및 방법: 자가 혈관을 이용한 동정맥루 조성술에 있어 조기개존율에 영향을 미치는 요인을 파악하고, 이를 향상시키기 위해서 2002년 6월부터 2003년 5월까지 1년 간 말기 신부전 환자에게 시행한 총 85예의 동정맥루 수술 중 두부정맥(cephalic vein)과 요골동맥(radial artery)의 단측문합(end-to-side anastomisis)을 시행한 49예를 대상으로 임상분석을 하였다. 걸과: 연구대상 49예에서 조기개존율은 79.6%였다. 환자의 나이나 성별, 고혈압과 당뇨병 유무에 따른 개존율의 차이는 없었으며 환자의 체질량지수 및 고혈압과 당뇨의 유병기간, 술 전 듀플렉스 검사로 측정한 요골동맥의 직경에 따른 조기개존율의 차이는 통계적으로 유의하지 않았다. 수술 전 듀플렉스 검사로 측정한 두부정맥의 직경과 수술 시 측정한 동정맥루의 혈류량이 조기개존율과 유의한 양의 상관관계를 나타내었고, 특히 혈관직경 2.7mm가 초과되는 군에서는 조기 폐쇄 없이 개존율이 100%로 유지되었으며 동정맥루의 혈류량이 100mL/min 이하인 군에서는 조기개존율 33.3%로 100 mL/min초과인 군의 82.2%와 비교할때 유의하게 조기개존율이 낮았다. 결론: 동정맥루에 사용되는 정맥의 직경은 개존율과 밀접한 관련이 있어 가능한 한 직경이 큰 정맥을 선택해야 하며 연구에 따라 다양한 기준이 보고되어 왔으나 보다 정확한 예후 판단을 위해서는 정맥의 직경뿐 아니라 혈관 유출로의 혈류와 협착상태 등에 대한 파악이 필요할 것으로 생각된다. 본 연구에서 측정한 수술 시 동정맥루의 혈류량을 기준으로 판단할때, 100 mL/min 이하의 혈류량을 나타내는 radiocephalic fistula에서는 혈류량 감소의 원인을 찾아 교정술을 시행하고 그 이후에도 혈류량이 증가하지 않을 경우 다른 부위의 혈관 또는 인조혈관의 사용을 고려하여야만 할 것이다.

• 대한의용생체공학회:의공학회지
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• 제19권1호
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• pp.33-38
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• 1998

심장내 이식형 축류 혈액 펌프의 개발을 시도하였다. 이 펌프는 해부학적인 적합성이 좋고, 혈액과 접촉하는 면적이 적으며, 심장판막의 위치에 이식할 수 있어 이식술이 용이한 등의 이점이 있다. 축류혈액펌프는 입펠러와 소형 모터에 의해 구성되었으며, 모터축과 펌프의 본체의 밀봉은 자성유체 축봉이 이용되었다. 본 연구에서 개발한 혈액펌프의 펌프 특성은 4매 임펠러의 경우 회전수 7091[rmp], 6매 임펠러의 경우 회전수 6402[rpm]에서 유량 5[l/min], 차압 100[mmHm]을 얻을 수 있었으며, 자성유체 축봉의 내압 특성은 회전수 7000[rpm], 압력ㄹ 150[mmHg]에서 24시간 이상의 내구성을 얻을 수 있었다. 그리고, 용혈에 대하여 검토한 결과 4매 임펠러의 1H 는 0.0561[g/100L]이고, 6매 임펠러의 경우는 1H=0.214[g/100L]을 얻을 수 있었다. 이상의 실험결과는 심장내 이식 축류형 혈액펌프의 실현 가능성을 보여 주는 것으로 앞으로 큰 기대를 걸수 있다고 생각된다.

• 한국전산유체공학회지
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• 제21권1호
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• pp.103-109
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• 2016

With the rapid increase in the number of patients with cardiopulmonary diseases, more cardiopulmonary circulatory assist devices are also needed. These devices can be employed when heart and/or lung function poorly. Due to the critical role they take, these devices have to be designed optimally from both mechanical and biomechanical aspects. This paper presents the CFD results of a baseline model of a centrifugal blood pump for the ECMO condition. The details of flow characteristics of the baseline model together with the performance curves and the modified index of hemolysis(MIH) are investigated. Then, the geometry of baseline impeller and the volute are modified in order to improve the biomechanical performance and reduce the MIH value. The numerical simulations of two cases represent that when impeller radius and prime volume decrease the MIH value also decreases. In addition, the modified geometry shows more uniform pressure distribution inside the volute. The findings provide valuable information for further modification and improvement of centrifugal blood pumps from both mechanical and biomechanical aspects.

• Korea-Australia Rheology Journal
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• 제19권2호
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• pp.61-66
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• 2007

The aggregation characteristics of red blood cells (RBCs) are known as important factors in the microvascular flow system, and increased RBC aggregation has been observed in various pathological diseases, such as thrombosis and myocardial infarction. This paper describes a simple microfluidic device for measuring the RBC aggregation by integrating a microfluidic slit rheometry and laser-backscattering technique. While a decreasing-pressure mechanism was applied to the microfluidic rheometry, a syllectogram (the light intensity versus time) showed an initial increase and a peak caused by the high shear stress-induced disaggregation, immediately followed by a decrease in the light intensity due to RBC aggregation. The critical shear stress (CST) corresponding to the peak intensity was examined as a new index of the RBC aggregation characteristics. The CST of RBCs increased with increasing aggregation-dominating protein (fibrinogen) in the blood plasma. The essential feature of this design was the combination of the rheometric-optic characterization of RBC aggregation with a microfluidic chip, which may potentially allow cell aggregation measurements to be easily carried out in a clinical setting.

• Neonatal Medicine
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• 제25권2호
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• pp.78-84
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• 2018

Purpose: To investigate the hemodynamic risk factors for necrotizing enterocolitis (NEC), we analyzed the characteristics of descending aorta (DA) blood flow in preterm neonates, who later developed NEC. Methods: This was an observational case-control study on 53 preterm neonates at a tertiary referral center. Clinical and echocardiographic data were collected from 23 preterm neonates with NEC (NEC group), and compared with those of 30 preterm neonates without NEC (control group). Echocardiography was done at a median (interquartile range) of 5 (3-9) days after birth and 2 (1-2.5) days before the diagnosis of NEC. Results: Basic clinical characteristics including gestational age, birth weight, Apgar score, breast feeding status, use of umbilical catheters, and mode of invasive ventilator care were similar between the groups. Compared with the control group, the lowest diastolic velocity of DA was significantly decreased, whereas the diastolic reverse flow and the ratio of diastolic reverse to systolic forward flows were significantly increased in the NEC group. In addition, the resistive index (RI) of DA was significantly increased in the NEC group and showed a positive association with the development of NEC. Multivariate logistic regression analysis showed that increasing RI of DA was an independent risk factor for the development of NEC (P=0.008). Conclusion: Significant changes in DA flow characteristics including decreased diastolic velocity and increased diastolic reverse flow along with increased peripheral vascular resistance were observed before the development of NEC in preterm neonates. These findings may help clinicians stratify in advance neonates at a risk of developing NEC and may help improve outcomes in these neonates.

• 동의생리병리학회지
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• 제26권5호
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• pp.610-614
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• 2012

This study was done to identify correlates of carotid artery ultrasonography's measurement and Inyoung pulse in college students. We measured the amplitude of Inyoung pulse, Chongu pulse, ratio of Inyoung to Chongu and ratio of Chongu to Inyoung on 30 college students. Also, We measured the Distance, Diameter), RI(resistivity index), S/D(systolic, diastolic ratio), PI(pulsatility index), PSV(peak systolic velocity), EDV(End diastolic velocity), Vmean using carotid artery ultrasonography. The data was analyzed by Pearson's correlation coefficient using SAS program. The results were as follow. Results showed a positive correlation between Inyoung pulse and diameter by carotid artery. It showed a positive correlation between Inyoung pulse and S/D. Also, It showed a positive correlation between Inyoung pulse and PSV. As a result, the strength of Inyoung pulse related with the diameter of carotid artery and blood flow velocity.

• 셀메드
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• 제12권3호
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• pp.10.1-10.12
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• 2022

Objective: The objective of the study was to evaluate the effect of Sharbat Afsantin in Polycystic Ovarian Disease. Methods: An open observational study was carried out in the Department of Ilmul Qabalat wa Amraze Niswan. Diagnosed cases(n=30) of PCOD were included in the study. Patients with thyroid dysfunction, systemic diseases, on hormonal treatment in last three months, pregnancy and lactation were excluded. Research drug (Sharbat Afsantin) was administered orally in a dose of 25ml twice daily for 15 days/cycle for three consecutive cycles. Outcome measures were, changes in subjective parameters (duration of cycle, duration and amount of flow and weight reduction) and objective parameters {pictorial blood loss assessment chart (PBAC) score, basal metabolic index (BMI), modified Ferriman Gallwey (mFG) score, acanthosis nigricans scale and pelvic ultrasonography}. Data were analyzed using paired Student 't' test. Results: Changes in duration of cycle, duration and amount of flow were achieved in 83.3%, 50% and 40% patients respectively and weight reduction in 30% patients. Changes in PBAC score and BMI were achieved in 50% and 30% patients respectively and 30% patients showed normal findings on pelvic ultrasonography. Conclusion: Sharbat Afsantin can be used as an alternate remedy in PCOD patients, as it has significant effect to regularize menstruation by reduction in BMI and probably by improving insulin resistance in PCOD. No adverse effect of Sharbat Afsantin was noted during the trial.