Molecular Characterization of Neurally Differentiated Human Bone Marrow-derived Clonal Mesenchymal Stem Cells

이택기,이현주,조윤경,전명신,송순욱 대한면역학회 2014 Immune Network Vol.14 No.1

Bone marrow-derived mesenchymal stem cells (MSCs) are multipotent, with the ability to differentiate into different cell types. Additionally, the immunomodulatory activity of MSCs can downregulate inflammatory responses. The use of MSCs to repair injured tissues and treat inflammation, including in neuroimmune diseases, has been extensively explored. Although MSCs have emerged as a promising resource for the treatment of neuroimmune diseases, attempts to define the molecular properties of MSCs have been limited by the heterogeneity of MSC populations. We recently developed a new method, the subfractionation culturing method, to isolate homogeneous human clonal MSCs (hcMSCs). The hcMSCs were able to differentiate into fat, cartilage, bone, neuroglia, and liver cell types. In this study, to better understand the properties of neurally differentiated MSCs, gene expression in highly homogeneous hcMSCs was analyzed. Neural differentiation of hcMSCs was induced for 14 days. Thereafter, RNA and genomic DNA was isolated and subjected to microarray analysis and DNA methylation array analysis, respectively. We correlated the transcriptome of hcMSCs during neural differentiation with the DNA methylation status. Here, we describe and discuss the gene expression profile of neurally differentiated hcMSCs. These findings will expand our understanding of the molecular properties of MSCs and contribute to the development of cell therapy for neuroimmune diseases.

Immunomodulatory Properties of Mesenchymal Stem Cells and Their Therapeutic Applications

이택기,송순욱 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.2

Mesenchymal stem cells (MSCs) are adult stem cells that can be isolated from most adult tissues, including bone marrow, adipose, liver, amniotic fluid, lung, skeletal muscle and kidney. The term MSC is currently being used to represent both mesenchymal stem cells and multipotent mesenchymal stromal cells. Numerous reports on systemic administration of MSCs leading to functional improvements based on the paradigm of engraftment and differentiation have been published. However, it is not only difficult to demonstrate extensive engraftment of cells, but also no convincing clinical results have been generated from phase 3 trials as of yet and prolonged responses to therapy have been noted after identification of MSCs had discontinued. It is now clear that there is another mechanism by which MSCs exert their reparative benefits. Recently, MSCs have been shown to possess immunomodulatory properties. These include suppression of T cell proliferation, influencing dendritic cell maturation and function, suppression of B cell proliferation and terminal differentiation, and immune modulation of other immune cells such as NK cells and macrophages. In terms of the clinical applications of MSCs, they are being tested in four main areas: tissue regeneration for cartilage, bone, muscle, tendon and neuronal cells; as cell vehicles for gene therapy; enhancement of hematopoietic stem cell engraftment; and treatment of immune diseases such as graft-versus-host disease, rheumatoid arthritis, experimental autoimmune encephalomyelitis, sepsis, acute pancreatitis and multiple sclerosis. In this review, the mechanisms of immunomodulatory effects of MSCs and examples of animal and clinical uses of their immunomodulatory effects are described.

직렬형 순간전압강하 보상기에 관한 연구

이택기,김한정 안성산업대학교 1997 論文集 Vol.29 No.2

This paper describes the Instantaneous Voltage Drop Compensator for instantaneous voltage drop. Instantaneous Voltage Drop Compensator has a capacitor bank as a compensation energy source. A serial type compensator has a shortage voltage compensation method. At a normal state, commercial voltage is supplied to a load. As voltage drops instantaneously the serial type compensator generates the shortage voltage by an inverter using the energy in capacitor bank and adds serially it to the input voltage. So, The load voltage remains constant. A 3Φ 20kva serial type Instantaneous Voltage Drop Compensator is made and also its controller is designed. The performance of the compensator is verified in experiments.

부하 불평형을 고려한 능동전력피터 성능 연구

이택기,박현식 안성산업대학교 2000 論文集 Vol.32 No.-

This paper presents the performance of a active power filter(APF) system in unbalanced load. The unbalanced load leads to negative sequence of current, and this makes 120㎐ ripple in dc-link voltage and increase the rating of APF. Thus, the separation of negative sequence was performed in synchronous reference frame and it was controlled to flow into supply network. The validity of this scheme is investigated through experimental results for a prototype APF system rated 10kVA.

풍선 보조 기법을 결합한 초음파 유도하 트롬빈 주입을 통한 후경골동맥의 가성동맥류 치료: 1예 보고

이택기,전용선,홍기천,조순구,김유진 대한영상의학회 2014 대한영상의학회지 Vol.70 No.5

An ultrasound-guided direct injection of thrombin is currently the first choice of treatment for the postcatheterization pseudoaneurysm, mainly in the femoral artery. A pseudoaneurysm in the posterior tibial artery is very rare, so there are not enough reports about proper treatment yet. We report a case of a balloon-assisted injection of thrombin under ultrasonography-guidance to manage a pseudoaneurysm in the posterior tibial artery and concurrently to prevent a distal artery embolization. 초음파 유도하 트롬빈 주입은 혈관도자술 후 가성동맥류에 대한 일차적인 치료법으로 활용되고 있으나 이는 주로 대퇴동맥에서 사용되며, 후경골동맥에 발생한 가성동맥류는 그 빈도가 매우 낮아 이에 대한 다양한 치료가 보고되고 있지 않다. 본 증례에서는 Fogarty 풍선카테터 사용 후 발생한 후경골동맥의 가성동맥류에 대해 초음파 유도하 트롬빈 주입과 풍선카테터의 보조적 활용으로 가성동맥류를 치료함과 동시에 원위부 동맥 색전증을 예방한 1예를 보고한다.

Multi-Focal Lobular Carcinoma In Situ Arising in Benign Phyllodes Tumor: A Case Report

이택기,최창환,김윤정,김미영,이경희,조순구 대한영상의학회 2015 대한영상의학회지 Vol.73 No.2

Coexistent breast malignancy arising in phyllodes tumor is extremely rare, and most of them are incidental reports after surgical excision. Coexistent malignancy in phyllodes tumor can vary from in-situ to invasive carcinoma. Lobular neoplasia is separated into atypical lobular hyperplasia and lobular carcinoma in situ (LCIS). LCIS is known to have a higher risk of developing invasive cancer. We reported imaging findings of multifocal LCIS arising in benign phyllodes tumor.

자화인덕턴스 변화를 고려한 약계자 영역에서의 유도전동기 벡터제어

이택기 한국조명전기설비학회 1999 조명·전기설비학회논문지 Vol.13 No.2

약계자 영역에서 토크는 자속에 직접적으로 영향을 받는다. 이 영역에서는 자속준위는 회전자 속도에 대하여 반비례로 감소시킨다. 자속이 감소함에 따라 자화인덕턴스는 증가하게 된다. 자회인덕턴스는 전류를 제어하기 위한 접압을 제한한다. 본 노문에서는 약계자 영역에서 q-축전압을 측정함으로써 자화인덕턴스의 변화를 계산하며, 이에 따라 기준 자화전류를 재조정한다. 컴퓨터 시뮬레이션 실험결과를 통하여 제안한 방법을 입증한다. 본 연구에서 제안한 알고리즘은 방적기계등의 적용분야의 가변속 구동시스템에 활용이 기대된다. In case of field weakening region, torque is directly affected by flux. In this region, the flux reference is cIecreased inversely proportional to the rotor speed. As the flux is decreased, the magnetizing inductance is nonnally increased The increased magnetizing inductance limited voltage for controlling current In this paper, rreasuring q axis voltage in field weakening region, magnetizing inductance in flux calculating can be readjusted. Computer simulation and experiment results demostrate the efficacy of the prqx>sed rrethod. Proposed algorithm is expected to the application of the adjustable drive system in the spinning and weaving field. field.

Emission of EML in PHOLED by red and green dopant position

이택기 한국진공학회 2017 한국진공학회 학술발표회초록집 Vol.2017 No.2

Voltage Compensation Under Instantaneous Power Failure

李宅基(Taeck-Kie Lee),玄東石(Dong-Seok Hyun) 대한전기학회 1993 전기학회논문지 Vol.42 No.5

순간전압강하 보상기의 설계와 해석

이택기(Taeck-Kie Lee),현동석(Dong-Seok Hyun),황용하(Yong-Ha Hwang) 대한전기학회 1991 대한전기학회 학술대회 논문집 Vol.1991 No.7