• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.113-119
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• 2003

In this paper we introduced optimized deformed shape to prevent the blood vessel disease caused by the discord of deformed shape in the end-to-end anastomosis. This study considered the preliminary deformed shape induced by suture in the anastomosis of artery and PTFE, artificial blood vessel, with different diameters. Then we analyzed the final deformed shape of the anastomotic part under the systolic blood pressure. 120mmHg(16.0kPa). The final deformed shape of the anstomotic part was analyzed with respect to the change of initial diameter ratio(R$_{I}$) and the PTFE thickness. Equivalent and circumferential stresses induced by the systolic blood pressure in the anastomosis were also analyzed with respect to the initial diameter ratio(R$_{I}$). The results obtained were as follows : 1. Considering the preliminary deformed shape induced by suture and the systolic pressure in the anastomosis, not intimal hyperplasia, the optimal initial diameter ratio(R$_{I}$) was 1.073. 2. As the initial diameter ratio(R$_{I}$) became larger, higher equivalent and circumferential stresses were induced. And all the maximum stresses occurred on the side of PTFE 0.4mm apart from the anastomosis.

• Proceedings of the Acoustical Society of Korea Conference
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• 1992.06a
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• pp.103-106
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• 1992

기존의 혈류 속도 측정 방법으로는 인체내에 반사 물질을 투입하는 Fick technique과 electromagnetic flowmeter등을 이용한 invasive method와 Ultrasonic Doppler method에 의한 noninvasive method가 이용되고 있다. 이 방법들은 혈과의 모양이나 혈관에서의 flow velocity profile등에 관한 정확한 정보를 얻을 수 없다. 이와같은 문제점들을 해결하기 위한 혈류속도 측정 방법으로 실험실 조건하에서 인체에서와 유사한 혈류측정 장치를 제작하여, vessel의 표본 체적내의 산란체로부터 후방산란되는 초음파 신호의 correlation을 이용한 Ultrasound Time Domain Correlation (UTDC) technique을 연구하였다. UTDC technique을 이용하여 유속을 측정한 결과, 12% 이하의 정밀도로 평균 유체 유속이 측정되었고, Ultrasonic Doppler method에서 측정할 수 없는 혈과의 모양과 혈관의 각 위치에서의 유속 및 혈관벽에 이물질의 존재여부를 명확히 판단할 수 있었다.

• Korean Journal of Radiology
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• v.25 no.4
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• pp.384-394
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• 2024

Objective: To evaluate the image quality of novel dark-blood computed tomography angiography (CTA) imaging combined with deep learning reconstruction (DLR) compared to delayed-phase CTA images with hybrid iterative reconstruction (HIR), to visualize the cervical artery wall in patients with Takayasu arteritis (TAK). Materials and Methods: This prospective study continuously recruited 53 patients with TAK (mean age: 33.8 ± 10.2 years; 49 females) between January and July 2022 who underwent head-neck CTA scans. The arterial- and delayed-phase images were reconstructed using HIR and DLR. Subtracted images of the arterial-phase from the delayed-phase were then added to the original delayed-phase using a denoising filter to generate the final-dark-blood images. Qualitative image quality scores and quantitative parameters were obtained and compared among the three groups of images: Delayed-HIR, Dark-blood-HIR, and Dark-blood-DLR. Results: Compared to Delayed-HIR, Dark-blood-HIR images demonstrated higher qualitative scores in terms of vascular wall visualization and diagnostic confidence index (all P < 0.001). These qualitative scores further improved after applying DLR (Dark-blood-DLR compared to Dark-blood-HIR, all P < 0.001). Dark-blood DLR also showed higher scores for overall image noise than Dark-blood-HIR (P < 0.001). In the quantitative analysis, the contrast-to-noise ratio (CNR) values between the vessel wall and lumen for the bilateral common carotid arteries and brachiocephalic trunk were significantly higher on Dark-blood-HIR images than on Delayed-HIR images (all P < 0.05). The CNR values were significantly higher for Dark-blood-DLR than for Dark-blood-HIR in all cervical arteries (all P < 0.001). Conclusion: Compared with Delayed-HIR CTA, the dark-blood method combined with DLR improved CTA image quality and enhanced visualization of the cervical artery wall in patients with TAK.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.44.1-44.1
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• 2010

poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a bacterially derived copolymer produced by fermentation. PHBV has been attractive because of its potential environmental, pharmaceutical and biomedical applications. Recently, the electrospinning technique has been used to fabricate fibrous mat for biomedical applications such as artificial blood vessel, drug release and scaffolds, because this method is simple and easy to get ultrafine polymer fibers. Depending on speed of rotation drum collector, fiber structure was different. In this work, PHBV fiber was aligned by electrospinnning machine. Furthermore, alignment of PHBV fiber mats was given angle such as $45^{\circ}$, $60^{\circ}$ and $90^{\circ}$. The morphology of each aligned PHBV fiber mat was observed by SEM technique. The mechanical property was evaluated depending on alignment angle. Especially, cell attachment ability depending on alignment of PHBV fiber mats was carried out using MG- 63 osteoblast like cells.

• Polymer(Korea)
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• v.39 no.1
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• pp.40-45
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• 2015

Simple poor-cosolvent casting was used to surface treat biodegradable elastic poly(L-lactide-co-${\varepsilon}$-caprolactone) (PLCL; 50:50) copolymer films that presented lotus-leaf-like structures. We evaluated whether the lotus-leaflike-structured PLCL (L-PLCL) films could be used as a biomaterial for artificial vascular grafts. The surface morphology, hydrophobicity, and antithrombotic efficiency of the films were examined while immersed in platelet-rich plasma (PRP) using scanning electron microscopy (SEM) and a contact angle meter. The recovery and crystallinity of the films were measured using a tensile-strength testing machine and an X-ray diffractometer, respectively. The solvent containing acetic acid, as a poor co-solvent, and methylene chloride mixed in a 1:2 ratio produced an optimal PLCL film with a water contact angle of approximately $124^{\circ}$. Furthermore, the surface of the L-PLCL films immersed in PRP showed a lower rate of platelet adhesion (<10%) than that of the surface of an untreated PLCL film immersed in PRP.

• Archives of Reconstructive Microsurgery
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• v.21 no.2
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• pp.153-158
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• 2012

Purpose: The first web space of the foot has a similar thickness and skin texture of the pulp of the fingers. Moreover, it has a reliable blood vessel and sensory nerve. The purpose of this study was to evaluate the clinical results of the first web space free flap to reconstruct the pulp of fingers. Materials and Methods: Authors have performed 23 cases of first web space free flap to reconstruct the pulp defect of the fingers between June 2004 and May 2009. The age of the patients ranged from 20 years old to 55 years old. The size of the flap ranged from $1{\times}1.5cm$ to $8.5{\times}2.5cm$. The mean flap area was 5.4 cm2. In 4 cases, we elevated the flap including lateral aspect of the big toe and medial aspect of the second toe. And then we made an artificial syndactyly to reconstruct the pulps on two fingers at the same time. In all cases, we performed 1 digital artery and 1 dorsal vein anastomosis. Every donor site that had a small defect healed spontaneously without any additional operations to cover it. Results: Of this type of surgery 21 flaps (91.3%) survived, 2 flaps (8.7%) failed. There was no severe complication in the donor sites. There was no walking disturbance due to the skin defect of the donor site. The static 2 point discrimination in 11 cases that we could check ranged from 3 mm to 15 mm. Conclusion: The authors believe that the first web space free flap of the foot is a good option for the reconstruction of the pulp of the fingers and it has a minimal donor site morbidity.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.98-100
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• 2003

Synthetic polymers such as PET and ePTFE have widely been used for artificial vascular patches. However, these materials cannot function for a long term as blood vessel due to thrombotic occlusion and calcification. To overcome this limitation, a biocompatible vascular patch was developed using stem cell and tissue engineering approach. Autologous bone marrow mesenchymal stem cells were differentiated into vascular endothelial cells and smooth muscle cells. These cells were seeded onto collagen patch matrices. The matrices were anastomosed to abdominal arteries in canine models. Prior to implantation, histological and scanning electron microscopical examination revealed stem cell adhesion and growth on the matrices. At 3 weeks, the implanted vascular patches were patent. Histological examination showed the regeneration of endothelium, media and adventitia in the grafts. Cell tracing analysis using fluorescent reagent showed that labeled stem cells were present in the implanted grafts and contributed to the regeneration of vascular tissues. This study may help us develop a tissue-engineered vascular patch appropriate for clinical applications.

• Journal of Chest Surgery
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• v.41 no.2
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• pp.277-280
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• 2008

Tuberculous aortitis is a very rare disease. Furthermore, it is all the more rare for it to be complicated by the development of an aortic aneurysm or the formation of aorto-bronchial fistula. If it is complicated by rupture of the aorta, mortality is very high. If the patient didn't contract tuberculosis, but was expectorating blood, we would have to carry out a chest CT promptly, in order to make a rapid and accurate diagnosis of this disease. A 46-year-old male patient was admitted due to the sudden onset of intermittent hemoptysis and chest discomfort. CT scans of the chest showed an aneurysmal change to the descending thoracic aorta, and the formation of an aorto-bronchial fistula, which originated from this aneurysm and communicated with its left lower lobe. We operated with an artificial vessel graft interposition of the descending thoracic aorta and a left lower lobectomy. Because the diagnosis was of tuberculosis, we started anti-Tbc medication and long term anti-Tbc medication was recommended.

• Journal of Chest Surgery
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• v.29 no.4
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• pp.373-380
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• 1996

Prevention of thromboembolism is the most important task in the development of bioconpatible small caliber artificial vascular graft. In normal vessels, vascular endothelial cells maintain homeosatsis by secreting numerous factors. The aim of this study is to develope a method which Improves biocompatibility of small caliver polyurethane graft using endothelial cell culture technique, and ev luate the efTectiveness of extracelluar matrix for endothelization which was produced by cultured fibroblast. Methods ; Multiporous polyurethane tube of 3 mm diameter, 0.3 mm thickness was manufactured for vascular graft. Three mongrel dogs were intubated and internal jugular veins removed. Extracelluar matrix produced by cultured flbrobast which was obtained from dog's internal jugular vein were coated to the polyurethane graft. Then, endothelial cells extracted from Jugular vein were cultured and fixed on the extracelluar matrix layer of vascular graft. Endothelial cell coated vascular grafts were implanted to the carotid arteries of experimental dogs as interposed autograft. Implanted grafts were removed after 3 and 6 weeks. As a control, PTFE graft was interposed on carotid artery. These experiments demonstrated that extracelluar matrix produced by fibroblast can afford a base for endothelial cell linings of polyurethane graft. Although thrombosis were developed on autografted en othelial cell coated graft, 33% opening was noticed, and showed less adhesion to adjacent tissue layer. These findings suggest that fiboblast produced extracelluar matrix which can be used for edothelial cell lining vascular graft, and by improving the cultured endothelial cell function, there will be a new modality for reducing thrombosis on small vascular graft.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.195-201
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• 2014

Body fluid has been studied for diverse fields like Ringer's solutions, artificial joint fluids, cell growth culture media because it plays a crucial role in controlling body temperature and acts as a solvent for diverse metabolite processes in the body and delivery media of mineral, energy source, hormone, signal and drug from and to cell via blood or lymphatic vessel by osmotic pressure or active uptake. Stratum corneum containing extracellular lipids and NMF (natural moisturizing factor) absorbs atmospheric water residing outside of cells and utilize it to hydrate inside of their own. This process is related to skin barrier function. In this study, we conducted the cell viability test with Cell Bio Fluid $Sync^{TM}$, which mimicks body fluids including amino acids, peptides, and monosaccharides to strengthen skin barrier, and the clinical skin improvement test with cosmetics containing Cell Bio Fluid $Sync^{TM}$. In the cell viability test, HaCaT cell was treated with PBS for 3 hours, followed by the treatment of a cell culture medium (DMEM) and isotonic solution (PBS) and Cell Bio Fluid $Sync^{TM}$ for 3 hours each. Then, MTT assay and image analysis were conducted. In the clinical skin improvement test, twenty-one healthy women participated. Participants applied cosmetics containing Cell Bio Fluid $Sync^{TM}$ on their face for a week and evaluated the skin hydration, skin roughness, brightness and evenness. All measurements were conducted after they washed off their face and took a rest under the constant temperature ($22{\pm}2^{\circ}C$) and constant humidity conditions ($50{\pm}5%$) for 20 minutes. All the data were analyzed by SPSS (version 21) software program. Results showed that Cell Bio Fluid $Sync^{TM}$ improved both the cell viability and in vivo skin conditions such as skin hydration, roughness, brightness and evenness.