• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.11
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• pp.985-990
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• 2013

An arteriovenous fistula is artificially produced using a graft for hemodialysis in patients. In an arteriovenous graft (AVG), the angle of its arterial or venous anastomosis play an important role in producing flows inside blood vessels, through which a stenosis may occur. Most studies thus far have focused on CFD results. In this study, a PIV technique is used to analyze the hemodynamic characteristics at the arterial or venous anastomosis of an AVG having an angle of $30^{\circ}C$. For flow dynamic similarity, the Reynolds number is set to be the same for real and simulated flows. A PIV experiment is performed with a control valve in the arterial part. In conclusion, the recirculation flow appeared in the bifurcation area and the total blood velocity changed according to the extent of valve opening.

• Macromolecular Research
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• v.16 no.1
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• pp.15-20
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• 2008

The enhanced permeability and retention (EPR) effect is used extensively for the passive targeting of many macromolecular drugs for tumors. Indeed, the EPR concept has been a gold standard in polymeric anticancer drug delivery systems. This study investigated the tumoral distribution of self-assembled nanoparticles based on the EPR effect using fluorescein and radio-labeled nanoparticles. Self-assembled nanoparticles were prepared from amphiphilic chitosan derivatives, and their tissue distribution was examined in tumor-bearing mice. The size of the nanoparticles was controlled to be 330 run, which is a size suited for opening between the defective endothelial cells in tumors. The long-circulating polymer nanoparticles were allowed to gradually accumulate in the tumors for 11 days. The amount of nanoparticles accumulated in the tumors was remarkably augmented from 3.4%ID/g tissue at 1 day to 25.9%ID/g tissue at 11 days after i.v. administration. The self-assembled nanoparticles were sustained at a high level throughout the 14 day experimental period, indicating their long systemic retention in the blood circulation. The ${\gamma}$-images provided clear evidence of selective tumor localization of the $^{131}I$-labeled nanoparticles. Confocal microscopy revealed the fluorescein-labeled nanoparticles to be preferentially localized in the perivascular regions, suggesting their extravasation to the tumors through the hyperpermeable angiogenic tumor vasculature. This highly selective tumoral accumulation of nanoparticles was attributed to the leakiness of the blood vessels in the tumors and their long residence time in the blood circulation.

• The Journal of Korean Obstetrics and Gynecology
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• v.31 no.1
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• pp.43-56
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• 2018

Objectives: This study was designed to investigate the basis for developing the herbal decoction that may help promote healthy blood vessels in accordance with the basic principles of Korean medicinal materials. Methods: In this study, we investigated the vascular relaxation effects of fifty herbal decoctions on vascular response in isolated thoracic aorta of phenylephrine-preconracted rats. Results: The results of identify the vascular relaxation effect of fifty herbal decoctions provided by Korea Institute of Korean Medicine, twenty-one herbal decoctions showed vascular relaxation effects. Among them, four herbal decoctions, Mahwang-tang (麻黃湯), Samchulgeonbi-tang (參朮健脾湯), Cheonwangbosim-dan (天王補心丹), and Socheonglyong-tang (小靑龍湯), with showed significantly concentration-dependent vasodilation was examined. Vascular relaxation level are $84.02{\pm}4.70$, $79.39{\pm}13.9$, $51.26{\pm}12.56$, and $54.73{\pm}15.8%$, respectively (P<0.05, 0.01, and 0.001). Conclusions: Thus these results provide a basic data for the treatment of the impairment of vascular function and blood pressure in traditional Oriental medicine.

• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.253-257
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• 2004

Platelet aggregation is a complex phenomenon that probably involves several intracellular biochemical pathways. When activated, platelets change shape, aggregate and release the contents of their intracellular granules. The interactions between platelets and blood vessel walls are important in the development of thrombosis and cardiovascular diseases. When blood vessels are damaged, platelet aggregation occurs rapidly to form haemostatic Plugs or arterial thrombi at the sites of vessel injury or in regions where blood flow is disturbed. These thrombi are the source of thromboembolic complications of atherosclerosis, heart attacks, stroke, and peripheral vascular disease. Therefore, the inhibition of platelet function represents a promising approach for the prevention of thrombosis. Plants constitute a rich source of bioactive chemicals such as phenolics, terpenoids and alkaloids. Plant extracts may be an alternative to currently used medicinal source because they constitute a rich source of bioactive chemicals. This study was performed to investigate the antiplatelet activity of extract of Tabebuia impetiginosa Martius ex DC (Taheebo) and find out which fractions to this activity in rabbit platelet. Taheebo was methanol extracted and solvent fractionated in to five fractions (hexane, chloroform, ethylacetate, butanol and water). And each fractions were investigated inhibitory effects on platelet aggregation induced by various agonists using washed rabbit platelets in vitro.

• Biomedical Science Letters
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• v.24 no.4
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• pp.411-417
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• 2018

The aim of this study was to investigate the impact of participation in the 622 km hyper-ultra-marathon on hepatic metabolism and renal function in middle-aged men. Healthy middle-aged male amateur ultra-marathoners between the ages of 40 and 60. Blood was collected at the pre-race, immediately after 300 km, 622 km hyper-ultra marathon race, 72 hours (3 day) and 144 hours (6 day) after the race, AST (aspartate aminotransferase), ALT (alanine aminotransferase), ALP (alkaline phosphatase), ${\gamma}$-GTP (gamma glutamyl transferase), T-Bil (total bilirubin), D-Bil (direct bilirubin), T-protein (total protein), albumin, uric acid, BUN (blood urea nitrogen), creatinne were analyzed. ALP was significantly increased at 300 km, 622 km, day 3 and day 6 than the pre-race. ${\gamma}$-GTP, T-protein, albumin, uric acid, BUN and creatinine were not significantly different between the distances and the recovery period respectively. AST and ALT were significantly increased at 300 km, 622 km, day 3 and day 6 than the pre-race, respectively (P<0.05) at day 3 and day 6 they showed significant decrease from 300 km and 622 km, respectively (P<0.05). T-Bil and D-Bil increased significantly at 300 km and 622 km, respectively (P<.05) and significantly decreased at day 3 (P<0.05) compared to the pre-race, at day 3 and day 6 they were decreased significantly than 300 km and 622 km, respectively (P<0.05). In conclusion, no disturbance of renal function was observed according to the distances and between the recovery period of 622 km hyper-ultra marathon race, but reversible hepatocyte function could be degraded and some hemolysis of blood vessels was induced.

• Fashion & Textile Research Journal
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• v.25 no.4
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• pp.508-519
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• 2023

Muscle reduction owing to aging causes changes in physical function among the elderly. Fitness compression wear reduces fatigue by compressing the main muscles, expanding blood vessels, and rapidly discharging lactic acid. The effect of clothing pressure when wearing fitness compression wear for the elderly was objectively and subjectively evaluated for six women aged 55-64 years. The evaluation clothes were three types of tops and bottoms, one type of design (A) preferred among the existing compression wear, and two types of design (B and C). The objective evaluation items included clothing pressure, blood flow, surface temperature, and subjective satisfaction. It was found that clothing A had the highest clothing pressure in the straight posture and five fitness movements. Blood flow increased the most when wearing the evaluation clothing. The surface temperature was found to be the highest for clothing C, and subjective satisfaction was found to be the best when wearing evaluation clothing B. If the tensile strength was low and the tensile elongation was high, as in evaluation clothing B, it was recognized as appropriate clothing pressure, and the subject was subjectively satisfied. When manufacturing fitness compression wear in the future, it will be possible to increase users' objective and subjective satisfaction with wearing it, if the incision of the garment were placed at the location of the line of non-extension (LoNE), and appropriate material characteristics are applied.

• Korean Journal of Radiology
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• v.2 no.1
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• pp.1-7
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• 2001

Objective: To determine the usefulness of perfusion MR imaging in assessing the histologic grade of cerebral gliomas. Materials and Methods: In order to determine relative cerebral blood volume (rCBV), 22 patients with pathologically proven gliomas (9 glioblastomas, 9 anaplastic gliomas and 4 low-grade gliomas) underwent dynamic contrast-enhanced T2^*-weighted and conventional T1- and T2-weighted imaging. rCBV maps were obtained by fitting a gamma-variate function to the contrast material concentration versus time curve. rCBV ratios between tumor and normal white matter (maximum rCBV of tumor / rCBV of contralateral white matter) were calculated and compared between glioblastomas, anaplastic gliomas and low-grade gliomas. Results: Mean rCBV ratios were 4.90°±1.01 for glioblastomas, 3.97°±0.56 for anaplastic gliomas and 1.75°±1.51 for low-grade gliomas, and were thus significantly different; p < .05 between glioblastomas and anaplastic gliomas, p < .05 between anaplastic gliomas and low-grade gliomas, p < .01 between glioblastomas and low-grade gliomas. The rCBV ratio cutoff value which permitted discrimination between high-grade (glioblastomas and anaplastic gliomas) and low-grade gliomas was 2.60, and the sensitivity and specificity of this value were 100% and 75%, respectively. Conclusion: Perfusion MR imaging is a useful and reliable technique for estimating the histologic grade of gliomas.

• Journal of Korean Foot and Ankle Society
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• v.28 no.3
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• pp.102-106
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• 2024

A reverse sural flap is a surgical procedure to repair soft tissue defects, usually in the ankle region. This procedure involves moving a tissue flap from the calf to cover a defect in the ankle. The flap is turned 180° so that the tissue around the wound is supplied with blood by the vessels at the base of the flap, typically preserving the sural nerve and artery. This method is particularly valuable when thick and robust tissue is required to cover defects resulting from traumatic injuries, chronic wounds, or post-skin tumor removal when the local tissue is insufficient for direct closure. In this case, a patient who had undergone surgery for a chronic ulcerative lesion on the Achilles tendon three years prior to presentation at the authors' hospital was treated using a half-width reverse sural flap. Modifications to the sural flap design may be crucial considering the surgical history, blood supply, and defect size around the lower leg. In particular, previous surgeries for lower leg fractures or ligament damage may limit blood supply and require flap design modifications.

• International Journal of Stem Cells
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• v.15 no.2
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• pp.136-143
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• 2022

Background and Objectives: Circulating endothelial progenitor cells (EPCs) participate in vascular repair and predict cardiovascular outcomes. The aim of this study was to investigate the correlation between EPCs and abdominal aortic aneurysms (AAAs). Methods and Results: Patients (age 67±9.41 years) suffering from AAAs (aortic diameters 58.09±11.24 mm) were prospectively enrolled in this study. All patients received endovascular aneurysm repair (EVAR). Blood samples were taken preoperatively and 14 days after surgery from patients with aortic aneurysms. Samples were also obtained from age-matched control subjects. Circulating EPCs were defined as those cells that were double positive for CD34 and CD309. Rat models of AAA formation were generated by the peri-adventitial elastase application of either saline solution (control; n=10), or porcine pancreatic elastase (PPE; n=14). The aortas were analyzed using an ultrasonic video system and immunohistochemistry. The levels of CD34⁺/CD309⁺ cells in the peripheral blood mononuclear cell populations were measured by flow cytometry. The baseline numbers of circulating EPCs (CD34⁺/CD309⁺) in the peripheral blood were significantly smaller in AAA patients compared with control subjects. The number of EPCs doubled by the 14th day after EVAR. A total of 78.57% of rats in the PPE group (11/14) formed AAAs (dilation ratio >150%). The numbers of EPCs from defined AAA rats were significantly decreased compared with the control group. Conclusions: EPC levels may be useful for monitoring abdominal aorta aneurysms and rise after EVAR in patients with aortic aneurysms, and might contribute to the rapid endothelialization of vessels.

• Pediatric Infection and Vaccine
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• v.17 no.2
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• pp.101-107
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• 2010

Purpose : In evaluation of patients, laboratory results are crucial in determination of a treatment plan. Obtaining venous blood from infants and children is a difficult procedure. Substitution of a capillary blood sample for a venous blood sample has been suggested. However, there are few studies showing mutual correlation between C-reactive protein (CRP) results in capillary and venous blood. This study was designed to determine whether the result of the capillary sample is the same as the result of the venous blood sample. Methods : After informed consent, a pair of venous and fingertip capillary blood samples were simultaneously collected from 100 children. The LC-178CRPTM was used for analysis of capillary blood and the Hitachi 7180 automatic hematology analyzer was used for analysis of venous blood. We compared CRP of both venous and capillary blood samples. Results were analyzed by crosstabulation analysis, simple regression analysis and the Bland Altman Plot method. Results : A close correlation (90.63%) was observed between capillary and venous blood analyzed by crosstabulation analysis. CRP results were similar between the two groups and showed a high coefficient correlation ($\beta$=1.3434, $R^2$=0.9888, P<0.0001) when analyzed by a simple regression model. The average value in venous blood was also higher compared to capillary blood. According to Bland Altman Plot analysis, lab results were measured at a 95% confidence interval. Conclusion : CRP results from capillary blood showed close correlation with venous blood sampling. At present, venous blood sampling is the preferred method. However, due to difficulty in venous blood sampling, capillary sampling could be considered as an alternative technique for use with children.