• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.219-222
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• 2001

The objective of the present study is to evaluate the effects of the stenting shapes on flow velocity and wall shear stress in angulated coronary stenosis by computer simulation. Coronary angiogram and Doppler ultrasound measurement in the patients with angulated coronary stenosis were obtained. Inlet wave velocity distribution obtained from in vivo intracoronary Doppler data was used for the numerical simulation. Spatial pattern of blood flow velocity and recirculation area were drawn through out the selected segment of coronary models. Wall shear stresses in the intracoronary stent models were calculated from three-dimensional computer simulation. A negative shear stress region, which is consistent with re-circulation area on flow pattern, was noted on the inner wall of post-stenotic area of pre-stenting model. The negative shear stress was disappeared after stenting. Shear stress in the post-stenting model was markedly reduced up to about two orders of magnitude compared to that of the pre-stenting model.

• 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.

• Journal of Yeungnam Medical Science
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• 제14권1호
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• pp.77-84
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• 1997

55명의 미숙아를 대상으로 이중 도플러 초음파 검사를 실시하여 대천문을 통한 전 뇌동맥의 혈류속도 및 혈류형태를 조사하였다. 미숙아에서 뇌 혈류속도 및 pulsatility index는 재태기간, 출생 체중, 및 미숙아의 나이 등의 증가에 따라 비례하여 증가하였으나 resistive index는 감소하였다. 뇌실 출혈이 있는 환아 군에서는 특징적인 resistive index의 증가가 보였지만 혈류속도 및 plusatility index는 불규칙하였다. 정상 미숙아의 뇌혈류 관찰 및 환아 군에서의 뇌혈류 검사에서 이중 도플러 초음파 검사는 비침습적이고 재현성도 뛰어나 선별검사로 유용한 방법이라고 생각한다.

• Journal of Korean Neurosurgical Society
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• 제29권7호
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• pp.923-928
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• 2000

Objective : The reliability of transcranial doppler sonography(TCD) for predicting delayed ischemic neurologic deficit( DIND) was investigated in patients with aneurysmal subarachnoid hemorrhage(SAH). Methods : The velocity of blood flow through the middle cerebral artery was measured by TCD in 70 patients treated surgically within 72 hours due to ruptured cerebral aneurysm. A correlation between measured maximal mean blood flow velocities and clinical factors including age, hypertension, Hunt-Hess grade, Fisher grade, DIND, and outcome was made. Results : An age-dependent reduction of the measured maximal mean velocities was found(r＝-0.4043, p<0.001). Flow velocities in hypertensive patients were significantly lower than in the normotensive individuals(two-tailed T test, p<0.05). There was no significant difference between the flow velocities and evaluated other clinical factors. When the flow velocities of 14 patients who developed DIND were compared with those of patients without deficits, no significant difference was seen. A significant increase in flow velocities in the days before the onset of DIND was found only in 4 of 14 cases. High flow velocities did not necessarily mean impending neurological deficits : 6 of 70 patients tolerated flow velocities over 160cm/s. Conclusion : We suggest that TCD readings have limited utility for predicting DIND following SAH, especially in older or hypertensive patients. More direct measurements of blood flow are necessary to adequately predict which patients are at high risk of DIND.

• 대한의생명과학회지
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• 제13권3호
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• pp.231-237
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• 2007

Subway environments such as crowd, passenger's gab, or subway-generated mechanical noise may become a potential stressor. The present study was sought to determine whether subway noise with or without mental activity affects cerebral hemodynamics and sympathetic system. Fifty-four healthy volunteers were divided group I which underwent subway noise (n=24) and group II which underwent a combined mental activity (mental arithmetic) with subway noise (n=30). Sympathetic factors such as heart rate (HR), blood pressure (BP) and heart rate-systolic pressure product (RPP), and mean blood flow velocity in the middle cerebral artery (MCAV) were measured before (baseline), during and after the noise-exposure. Systolic and diastolic blood pressure, HR and RPP significantly increased in group II (P<0.05) but not in group I during the noise-exposure. Peak-MCAV, diastolic-MCAV and mean-MCAV in the both groups were elevated during the noise-exposure (P<0.05) and the increased ratios in group II were greater than those in group I. These results suggest that a combined mental activity with subway noise may be a stressor which affects cerebral hemodynamics and sympathetic system.

• 대한의용생체공학회:의공학회지
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• 제30권2호
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• pp.129-134
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• 2009

The ideal method which measures a blood vessel of senility and degree of arteriosclerosis is to measure compliance of arterial and condition of blood circulation at the periphery. In these days vascular stiffness have been assessed by analyzing PTT (pulse transit time) from ECG and PPG. PTT is that between toe and finger each subject estimated through ECG and PPG signals. Two parameters, which are related to PWV, were tested with the time delay between the finger and toe. PWV is a variation of quantity which is associated with vascular stiffness. These researches which use PTT and PWV don't consider the blood vessel characteristic of an individual. In this current research, we have used with the blood vessel characteristic of an individual. That is an assessment of vascular stiffness using the variation of quantity in PWV with the changes of position in the subject. PWV variation increased as functions of the subject's age. The increase of the PWV variation parameters with age is attributed to the direct decrease of the blood vessel compliance with different position. The quantity of variation estimated by experimental results is that old age's (75.78${\pm}$7.75) case is 113.68% and young age's (26.47${\pm}$2.04) case is 85.69%. We proved and presented about estimation of vascular stiffness of possibility by this result.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.108-108
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• 2003

The current study was performed to observe the effects of Panax ginseng (PG) and P. quinquefolia (PQ) on hemodynamics such as blood flow rate (BF), blood flow velocity (BV), heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP, and body temperature (BT) in healthy young men. After testing equality of variance, Student's t-test using PROC TTEST was examined to. prove statistical differences between control and ginseng conditions at each time point. It was found that the BF data were fluctuated by personal deviation. In order to minimize the deviation, the results obtained for 6 hrs were reconstituted after dividing them into two periods of the first half from 1 to 3 hrs and of the latter half from 3.5 to 6 hrs. And then the reconstitution data and dose-response curves were obtained. Blood flow such as BF and BV shows significant increases both two periods in the dose of PG 2.25 and PG 9.0, whereas significant decrease in the dose of PG 4.5. However, in the PQ groups, the middle dose PQ 4.5 shows the highest significant increase among the three doses. Except for PG 2.25 in HR, other doses show significant decreases both in the first half and latter half. SBP of PQ 9.0 shows only a significant decrease in the first half; on the other hand, in the latter half, PG 4.5, PG 9.0 and PQ 9.0 significantly increase SBP. In addition, DBP of PG 2.25 and PG 4.5 show significant increase in the both periods. In the BT, PQ groups show gradual decrease from PQ 2.25 to PQ 9.0; however, PG groups show differently. PG 4.5 shows significant decrease, but PG 9.0 shows a increase without statistical meanings. In summary, PG is more effective in respect to keeping homeostasis of hemodynamics.

• 대한한의학회지
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• 제31권2호
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• pp.114-123
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• 2010

Objectives: This study was performed to investigate the effect of cold stress on heart rate variability and peripheral blood flow by Doppler ultrasound in healthy subjects. Methods: We classified the subjects by their Yin or Yang tendency using a Yin-Yang questionnaire. Cold stress was taken on the left hand of subjects for 10 seconds. Heart rate variability and peripheral blood flow were measured on the right radial artery before and after cold stress. Results: The Yang tendency group showed a significant decrease of heart rate after cold stress which was not seen in the Yin tendency group. The Yang tendency group showed a decrease of LF, total power, and increase of HF after cold stress, while the Yin tendency group showed the opposite. However, there were no statistically significant differences of heart rate variability analysis between the results of the two groups before and after cold stress. Recovery time of blood flow velocity by ultrasound Doppler was significantly different between the Yin and Yang tendency groups after cold stress. Conclusion: These results suggest that people with Yin or Yang tendency may show different responses in the autonomic nervous system. Further modified studies may include the responses to various manipulation techniques in acupuncture treatment and the individual responses according to pattern identification in traditional Korean medicine.

• 대한임상검사과학회지
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• 제55권3호
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• pp.219-226
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• 2023

뇌혈류초음파(TCD) 검사는 일반적으로 2 MHz의 낮은 주파수를 이용해서 두개강 내의 혈류속도 및 파형을 측정하는 검사이다. 많은 병원에서 병리사들이 검사를 시행하고 있고 학교, 뿐만 아니라 학회차원에서 교육들도 이루어지고 있다. 하지만 TCD검사는 검사자의 스킬이 무엇보다 중요한 검사 중에 하나다. 처음으로 검사를 접하는 검사자들은 혈관이 잘 찾아지지 않아 고민이 생기고, 어느 정도 경험한 검사자들은 혈관이 너무 많이 찾아져서 고민이 된다고 한다. 직접 혈관을 보고 측정하는 검사가 아니기 때문에 많은 제한과 어려움이 있을 수밖에 없다. 그래서 TCD 검사자들을 위해서 검사를 시행할 때 주의사항과 노하우를 소개함으로써 도움을 드리고자 한다.

• 한국임상수의학회지
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• 제38권3호
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• pp.163-168
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• 2021

A 6-year-old, spayed female, Maltese dog with tachypnea and dry cough was presented to Gyeongsang National University Veterinary Medical Teaching hospital. On physical examination, its respiration rate was 132 per minute. Decreased partial pressure of oxygen, partial pressure of carbon dioxide, and hyperlactatemia were found on arterial blood gas analysis. Its diastolic blood pressure was 80 mmHg. Auscultation revealed arrhythmia. Electrocardiogram revealed P pulmonale, P mitrale, and ventricular premature complexes. Thoracic radiographs revealed mild enlargement of both atrium and moderate enlargement of the left ventricular. There was also a moderate alveolar pattern in the right and caudal part of the left cranial lung lobe. Two-dimensional echocardiography showed enlargement of generalized four chambers without remarkable findings of valvular degeneration. M-mode echocardiography showed decreased left ventricular fractional shortening and enlarged left ventricular internal diameter at both end-systolic and end-diastolic. Color-flow Doppler imaging revealed eccentric turbulent flow starting below the left ventricular outflow tract and extending into the left atrium during systole. Spectral Doppler recordings revealed a high velocity flow through the mitral, tricuspid, aorta, and pulmonic regurgitation. Restrictive transmitral flow revealed high E-wave velocity, short E-wave deceleration time, and reduced A-wave velocity. There was also low ejection velocity thorough left ventricular out tract flow. Based on echocardiographic examination, dilated cardiomyopathy was the tentative diagnosis. The dog was medicated with inotropes, angiotensin converting enzyme inhibitor, and diuretics. At the 10-day following-up, the dog died suddenly. This report describes echocardiographic diagnosis and prognosis of dilated cardiomyopathy rarely reported in small breed dogs.