• Clinical Pain
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• v.19 no.2
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• pp.80-89
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• 2020

Objective: We compared the regenerative effects of microcurrent therapy (MT) according to the type of electric current, which were direct current microcurrent therapy (DCMT) and alternating current microcurrent therapy (ACMT) on atrophied calf muscle in cast-immobilized rabbit. Method: Rabbits were allocated into control group (sham MT), ACMT group, and DCMT group. Before starting treatment, right gastrocnemius (GCM) muscle was immobilized by cast for 2 weeks. Compound muscle action potential of tibial nerve in nerve conduction study, circumference of calf muscle using a ruler, and thickness of medial and lateral GCM muscle measured by ultrasound, cross sectional area (CSA), and proliferating cell nuclear antigen (PCNA) ratios (%) of muscle fibers were measured on the immunohistochemical analysis. Results: The mean atrophic changes (%) in right medial and lateral GCM muscle thickness, right calf circumference, and amplitude of CMAP of the right tibial nerve in ACMT group and DCMT group were significantly lower than those in control group, respectively (p<0.05). The mean CSA (μm²) of type I and type II and PCNA ratios (%) of medial and lateral GCM muscle fibers in ACMT group and DCMT group were significantly greater than those in control group, respectively (p<0.05). There were no significant differences between the ACMT group and DCMT group at all parameters. Conclusion: This study demonstrated that ACMT and DCMT showed better regeneration effect than sham MT. Microcurrent may be effective in regeneration of atrophied muscle regardless of the type of current.

• Journal of Korean Orthopaedic Sports Medicine
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• v.4 no.1
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• pp.18-28
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• 2005

Purpose: The purpose of this study is to evaluate the clinical, radiological and histopathological results after microfracture surgery for degenerative arthritis of the knee. Materials and Methods: From Oct. 1997 to Dec. 1998, 48 knees in 46 patients were treated by microfracture technique. Their mean age at the time of operation was 56 years(range, 40-75 years) and mean period of follow-up study was one year(range, 7-20 months). For 24 knees in 22 patients, 'second-look' arthroscopies and biopsies were performed at 6 months following microfracture. At the last follow up clinical results were evaluated with Baumgaertner's scale. The specimens of 24 cases were stained with H-E, Safranin-O, and Masson's trichrome. Eighteen of 24 cases were stained immunohistochemically and the Western blotting test was performed on 12 cases for type II collagen. We analyzed the relationship of the Western blotting for type II collagen with clinical score, preoperative varus deformity, joint space widening in radiological result, extent of repaired articular cartilage in '2nd-look' arthroscopic findings, patient's age and weight. Results: Clinical results were excellent in 90% and good in 10%. Among the 24 knees, more than 80% of areas of chondral defect were covered with regenerated cartilage in 21 knees Histologically, the repaired tissue appears to be a hybrid of hyaline cartilage and fibrocartilage. Repaired cartilage contains variable amounts of type II collagen with immunohistochemical staining. The results of the Western blotting test were similar. The amounts of type II collagen formation had positive correlation with the extent of repaired cartilage and preoperative varus deformity. Conclusion: 'Second-look' showed that the chondral defect areas were covered with newly grown grayish white tissue. Articular cartilage repair was confirmed with histological and immunohisto-chemical study qualitatively, and the amount of type II collagen was calculated with the Western blotting test quantitatively. The exact nature and fate of repaired cartilagenous tissues need further long term follow-up study. The results of this study provide the rationale to select osteoarthritic patients indicated for microfracture surgery.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.391-398
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• 2018

Mesenchymal stem cells (MSCs) are an attractive resource for refractory patients because of their anti-inflammatory/immunomodulatory capability and multi-lineage differentiation potential. The transplantation of MSCs has led to positive results in preclinical and clinical application to various diseases, including autoimmune disease, cardiovascular disease, cancer, liver cirrhosis, and ischemic stroke. On the other hand, studies have shown that paracrine factors, not direct cell replacement for damaged cells or tissue, are the main contributors in MSC-based therapy. More recently, evidence has indicated that MSC-derived exosomes play crucial roles in regulating the paracrine factors that can mediate tissue regeneration via transferring nucleic acids, proteins, and lipids to the local microenvironment and cell-to-cell communication. The use of these exosomes is likely to be beneficial for the therapeutic application of MSCs because their use can avoid harmful effects, such as tumor formation involved in cell transplantation. Therefore, therapeutic applications using MSC-derived exosomes might be safe and efficient strategies for regenerative medicine and tissue engineering. This review summarizes the recent advances and provides a comprehensive understanding of the role of MSC-derived exosomes as a therapeutic agent.

• Journal of Korean Orthopaedic Sports Medicine
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• v.3 no.2
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• pp.93-97
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• 2004

Continued research needs to be devoted to understanding the natural history of rotator cuff tears. Recent studies have shown progression of tear, symptomatic flare-ups and irreversible change in rotator cuffs managed nonsurgically. These data allow the grouping of patients with rotator cuff tears into three categories based on risk-benefit ratios. Nonsurgical care should be maximized for patients with impingement symptoms only, with partial-thickness tears, with chronic tears, and for the elderly patients. The proper selection of candidates for nonsurgical management should lead to the high success rate quoted by multiple authors. Even though conservative treatment is necessary, early surgery should be considered for tears that are acute, small or medium, associated with shoulder loss of function, or occur in a younger patient. Prolonged nonsurgical care in these patients risks tear propagation and irreversible changes to the cuff, which may complicate rotator cuff repair.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.77-80
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• 2018

360 VR 콘텐츠는 기존의 선형적인 일반 영상에 비해 사용자에게 더 많은 정보와 높은 몰입감을 제공할 수 있어 의학, 군사, 교육, 게임 등 다양한 분야에서 활용되고 있다. 최근에는 모바일 기기의 성능 향상과 통신기술의 발달에 힘입어 모바일 네트워크를 사용한 360 VR 콘텐츠 소비가 증가하는 추세이다. 모바일 네트워크는 대역폭이 한정적이고 가변적인 특성이 있어 이를 통해 용량이 큰 360 VR 콘텐츠 전송 시 초기 접속 지연 및 재생 끊김이 발생하여 사용자의 만족도를 감소시킬 수 있다. 이에 본 논문은 위에 언급한 문제를 해결하기 위해 360 VR 콘텐츠 전송 시 전체 요구대역폭을 감소시키고 사용자 초기 접속 속도를 향상시키는 것을 목표로, 360 VR 콘텐츠의 지오메트리 값과 사용자의 요(i.e. yaw)값을 활용하여 각도 기반으로 사용자의 현재 시점에 해당하는 타일을 확인하고 해당 타일에 높은 비트율을 할당하는 방법 및 웹 기반 전송에 대해 연구 개발하였다. 이를 위하여 웹 기반 3D 렌더링 API 인 WebVR API, HTTP Adaptive Streaming 기술의 표준 MPEG-DASH의 dash.js API를 활용하여 개발하고, 성능 확인 실험을 통해 요구대역폭 감소, 클라이언트 접속 속도 향상을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.322-325
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• 2022

삼킴 장애 환자는 뇌졸중, 치매, 외상성 뇌손상, 파킨슨병, 암이 주요 원인으로 급속히 증가하고 있다. 특히 고령화 사회가 되면서 더욱 삼킴 장애 환자는 늘어날 것으로 전망하고 있다. 고령 환자의 삼킴 이상의 진단을 위해 가장 많이 사용하고 있는 검사법으로는 비디오 조영 삼킴 검사(VFSS)이다. VFSS는 진단에 있어서 숙련된 전문의가 필요하기 때문에 대학병원 급에서 주로 시행하며, 고령 환자에게는 분석 결과를 상담받을 때까지 오랜 시간을 소요해야하는 문제점들이 있다. 본 논문에서는 삼킴 장애 진단을 위한 의료영상 관리 및 라벨링 시스템에 대해서 기술한다. 이를 구현하기 위해 서버에서 대용량 멀티프레임 영상을 성능 저하 없이 핸들링 하고 라벨링 데이터 생성을 위한 라벨링 툴을 구현하였다. 차후 라벨링 데이터를 생성하고 학습을 통하여 삼킴 장애 진단을 위한 인공지능 모델을 개발하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.8-10
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• 2023

삼킴장애는 음식물이 입에서 식도로 가지않고 걸리거나 기도(Trachea)로 흡입되는 문제를 갖는 상태이다. 특히 노인이나 신경계 질환을 앓는 환자의 경우 기도로 흡입된 음식덩이가 폐렴을 일으키고 결국에는 사망으로 이어지기에 적절한 치료와 관리가 요구된다. 보통 영상으로 판단할 수 있는 삼킴단계는 구강준비단계(Oral Preparatory Phase), 구강단계(Oral Phase), 인두단계(Pharyngeal Phase), 식도단계(Esophageal Phase) 4가지로 분류하고 삼킴장애는 침습(Penetration)과 흡인(Aspiration)으로 크게 2가지로 분류한다. 본 논문에서는 이러한 6가지 클래스를 가지는 삼킴장애 환자 비디오 파일을 라벨링하기 위한 웹 애플리케이션을 제안한다. 이를 구현하기 위해서 대용량 멀티프레임 이미지를 수신해서 분리하여 저장하도록 개발하였다. 또한 음식덩이를 정교하게 분할할 수 있도록 GrabCut 알고리즘을 적용하여 라벨링할 수 있도록 하였다. 차후 라벨러와 전문의 간의 협업이 가능하도록 라벨링 데이터의 상태를 관리할 수 있도록 개발하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.326-335
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• 2021

This study was undertaken to determine the effect of fermented soybean extract and its fractions on skin cell proliferation and growth. The extract was procured by the pepsin and Lactobacillus rhamnosus fermentation of soybean. LC-MS analysis was performed subsequent to soybean fermentation, and cell viability was measured by the WST-1 assay. Cell proliferation was observed to increase after exposing cells to the fermented soybean extract and its fractions at all concentrations tested (0~2,000 ㎍/mL). In particular, compared to the normal control group and 120 % proliferation of the EGF (epidermal growth factor) positive control group, 160~180 % cell proliferation was achieved at 800 ㎍/ml, indicating the excellent potential as an application material for skin aging inhibition and skin cell regeneration. In addition, we also examined the effects of fermented soybean extract and its fractions on wound healing ability, in HaCaT cells and fibroblasts. Our results indicate excellent cell migration abilities after treatment with fermented soybean extract and its fractions, as compared to the control treatment. Similar cell migration abilities were observed in the positive control group (EGF). Taken together, our results indicate that fermented soybean extract and its fractions (F4 and F5) exert amelioratory effects as a natural material for skin.

• Journal of Life Science
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• v.29 no.12
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• pp.1337-1344
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• 2019

Osteoporosis is characterized by a reduction in bone mass and typically manifests as an increase in fractures. Because this disease is common in elderly populations and lifespans are rapidly increasing, the incidence of osteoporosis has also grown. Most drugs currently used for osteoporosis treatment target osteoclasts in the bone tissue to prevent absorption. However, these medications also cause certain side effects and, furthermore, cannot increase bone mass. Thus, in order to control osteoporosis, regenerative medicine that utilizes adult stem cells and osteoblasts has been extensively studied. Statins, also known as 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, are cholesterol-lowering drugs that have been widely prescribed for cardiovascular diseases. Interestingly, recent studies have reported the beneficial effects of various statins on bone formation via the activation of osteoblasts. Thus, the current study investigated the effects of seven statin-family drugs on osteoblast activity during osteogenic differentiation using adult stem cells from human periosteal tissue. Specifically, statin effects on alkaline phosphatase activity, an early marker of bone cell differentiation, and on calcium deposit, a late marker of bone cell differentiation, were assessed. The results demonstrate that some statins (for example, pitavastatin and pravastatin) have a weak but positive effect on bone formation, and the findings therefore suggest that statin treatments can be a novel modulator for osteogenic differentiation and regenerative medicine using periosteal stem cells.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.364-373
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• 2011

Human embryonic stem cells have been highlighted as a valuable cellular source in the regenerative medicine field, due to their pluripotency. However, there is the challenge of the establishment of specific functional cell type forms of undifferentiated human embryonic stem cells (hESC). To establish and purify functional cell types from hESCs, we differentiated undifferentiated hESCs into vascular lineage cells and sorted the specific cell population from the whole cell population, depending on their cell volume, and compared them with the non-sorted cell population. We observed that about 10% of the PECAM positive population existed in the VEGF induced differentiating human embryoid body (hEB), and differentiated hEBs were made into single cells for cell transplantation. After making single cells, we performed cell sorting using a fluorescence-activated cell sorter (FACs), according to their cell volume on the basis of FSC region gating, and compared their therapeutic capacity with the non-sorted cell population through cell transplantation into hindlimb ischemic disease model mice. 4 Weeks after cell transplantation, the recovery rate of blood perfusion reached 54% and 17% in the FSC regions of sorted cells- and non-sorted cells, respectively. This result suggests that derivation of a functional cell population from hESCs can be performed through cell sorting on the basis of cell volume after preliminary differentiation induction. This approach may then greatly contribute to overcoming the limitations of marker sorting.