• 한국발생생물학회지:발생과생식
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• 제11권3호
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• pp.235-243
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• 2007

인간 제대혈 세포는 조혈모세포, 중간엽 줄기세포와내피전구세포를 풍부하게 포함하고 있다. 인간 제대혈 속의 중간엽 줄기세포는 조혈모세포와는 달리 다능성 줄기세포이며 신경세포로 분화할 수 있는 잠재성을 가지고 있다. 본 연구에서는 세포배양을 통해 제대혈의 중간엽 줄기세포를 신경세포와 콜린성 신경세포로 분화를 유도하였다. 중간엽 줄기세포를 신경세포로 분화시키기 위해 배양액에 dimethyl sulphoxide(DMSO)와 butylated hydroxyanisole(BHA)를 첨가하여 유도하였으며 basic fibroblast growth factor(bFGF), retinoic acid(RA), sonic hedgehog(Shh)를 처리하여 콜린성 신경세포로 분화시켰다. DMSO와 BHA에 처리된 중간엽 줄기세포가 빠르게 신경세포 모양으로 분화하는 것을 관찰하였으며, 이것은 면역조직학적 염색에서 신경세포 특이 표지인 $\beta$-tubulin III, 별아교세포에 대한 특이 표지인 GFAP, 희돌기아교세포에 대한 특이 표지인 Gal-C에 대해 양성반응을 나타내었고, 그 비율은 각각 $32.3{\pm}2.9%$, $11.0{\pm}0.9%,\;9.4{\pm}1.0%$였다. RT-PCR 분석에서 배양 단계에 따라 신경세포에 특이적인 표지 인자가 발현됨을 통해, 중간엽 줄기세포가 신경세포로 분화됨을 확인하였다. 또한, 중간엽 줄기세포에 bFGF, RA, Shh를 처리하여 콜린성 신경세포로 분화시켰을 때, 전체 중간엽 세포 중 $31.3{\pm}3.2%$가 신경세포 특이 표지인 $\beta$-tubulin III에 양성반응을 보였으며 이들 세포 중 $70.0{\pm}7.8%$가 콜린성 신경 특이 표지인 ChAT에 양성반응을 보였고, 이것은 Woodbury 방법에 의한 신경분화의 경우보다 3배 가량 높은 비율로 콜린성 신경의 분화를 유도한 것이다. 이러한 실험 결과들은 인간 제대혈의 중간엽 줄기세포가 콜린성 신경세포로 분화가 가능하고 이러한 잠재성을 가진 제대혈 중간엽 줄기세포는 퇴행성 신경질환에 대한 세포 치료제로서 가능성을 제시한다.

• Annals of Clinical Neurophysiology
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• 제4권1호
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• pp.12-15
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• 2002

Background : Changes in firing pattern and in the recruitment order of single motor unit(MU) have been claimed to be characteristic of central motor lesions, and a reduced firing rate was found in upper motor neuron lesions. But these findings have been rarely studied before in Korea, so we studied initial MU recruitment pattern in stroke patients with hemiparesis. Methods : We studied six patients(3 men and 3 women) whose mean age was $60.6{\pm}7.4$ years. A mean $20.6{\pm}16.2$ months had elapsed since the stroke. To compare the initial MU activation patterns in proximal and distal segments of paretic limb with their contalateral unaffected counterparts, we studied the onset and recruitment intervals in biceps brachii(BB) and first dorsal interossei(FDI) muscles in paretic and healthy arms. In a single muscle we examined from 5 to 10 individual MUs. And in a single motor unit, both the onset interval and the recruitment interval was examined. Results : The mean onset interval in paretic limb was significantly(p<0.05) longer than unaffected limb at proximal and distal location: BB $118.5{\pm}17.8$ msec vs $96.1{\pm}8.3$ msec(n=58); FDI $125.8{\pm}16.7$ msec vs $101.5{\pm}17.2$ msec(n=38). The mean recruitment interval in paretic limb was also significantly(p<0.05) longer than unaffected limb: BB $87.7{\pm}14.9$ msec vs $73.4{\pm}11.5$ msec(n=53); FDI $96.3{\pm}16.4$ msec vs $87.7{\pm}14.1$ msec(n=38). Conclusion : The first recruited MU had a lower baseline firing rate and the second recruited motor unit potential appeared earlier in paretic than in healthy muscles. And these findings may explain one of the reasons for paresis in patients with stroke.

• 한국지능시스템학회논문지
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• 제7권4호
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• pp.65-73
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• 1997

본 논문에서는 진화연산을 이용하여 동적 귀환 신경망의 구조를 저차원화하는 방법을 제안한다. 일반적으로 진화연산을 개체군을 이용한 탐색 방법으로서 신경회로망의 여러 가지 다른 성질을 동시에 최적화할 필요가 있을 때 유용한 방법이다. 본 연구에서는 동적 귀환 신경망의 구조를 조차원화하기 위하여 진화 프로그래밍으로 신경망의 구조를 탐색하고, 진화전략으로 신경망의 연결강도를 학습시킴으로서 전체적인 구조를 저차원화하였다.신경망의 중간층 노드의 추가/삭제는 돌연변이 확률에 의하여 결정한다. 노드를 삭제할 경우에는 입력 연결강도의 총합이 가장 작은 노드를 삭제하고, 노드를 추가할 경우에는 미리 지정한 확률함스에 따라 노드를 추가한다. 그리고 추가된 노드와 다른 노드와의 연결방법은 서로 영향을 미칠 수 있는 모든 연결강도 중에서 확률적으로 선택하여 연결하였다. 마지막으로 제안한 저차원화 동적 귀환 신경망이 완전 연결된 신경망보다 더 좋은 성능을 얻을 수 있음을 예제로서 본 논문에서는 도립진자의 안정화 및 제어와 로봇 매니퓰레이터의 비주얼 서보잉에 적용하여 컴퓨터 시뮬레이션을 통하여 그 유효성을 확인한다.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.79-79
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• 2003

Embryonic stem cells are capable of differentiating into a variety of cell lineages. However, the ultimate results of differentiation in vitro greatly depend on the duration of treatment and kinds of differentiating inducers added. In order to investigate the efficiencies of various differentiation inducers and the methods of treatment, we examined differentiation patterns of human embryonic stem cell (hESC, MB03) according to several different protocols. Exp. I) Upon differentiation using retinoic acid and ascorbic acid (RA/AA), embryoid bodies (EB, for 4days) derived from hESC was exposed to Rh (10$^{-6}$ M) and AA (50 mM) for 4 days, and were allowed to differentiate in N2 medium for 7, 14, 21, or 28 days. Exp. II) When bFGF was used, neuronal precursor cells were selected for 8 days in N2 medium after EB formation. After selection, cells were expanded at the presence of bFGF (20 ng/ml) for another 6 days followed by a final differentiation in N2 medium for 7, 14, 21 or 28 days. Exp. III) In addition, to examine the effects of neurotrophic factors in the production of mature neurons, groups of cells were exposed to either BDNF (5 ng/ml) or TGF-$\alpha$(10 ng/ml) during the 28 days of final differentiation. Differentiation patterns of RA/AA or bFGF treated groups were very similar; approximately 82% and 83% of the cells, respectively, were positive for anti-NF200 antibody, while it was about 10% and 11%, respectively, for anti-NF160 antibody in 28 days in N2 medium. Alsor, cells expressing TH were as low as 5%, while the cells doubled when matured at the presence of either BDNF or TGF-$\alpha$. Cells immunoreactive to anti-GAD antibody were approximately 20%. These results suggest that a maturation step rather than differentiation induction step, which is formation of EB, effects more decisively to the ultimate differentiation pattern.

• Clinical and Experimental Otorhinolaryngology
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• 제11권4호
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• pp.224-232
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• 2018

Objectives. Spiral ganglion neurons (SGNs) include potential endogenous progenitor populations for the regeneration of the peripheral auditory system. However, whether these populations are present in adult mice is largely unknown. We examined the presence and characteristics of SGN-neural stem cells (NSCs) in mice as a function of age. Methods. The expression of Nestin and Ki67 was examined in sequentially dissected cochlear modiolar tissues from mice of different ages (from postnatal day to 24 weeks) and the sphere-forming populations from the SGNs were isolated and differentiated into different cell types. Results. There were significant decreases in Nestin and Ki67 double-positive mitotic progenitor cells in vivo with increasing mouse age. The SGNs formed spheres exhibiting self-renewing activity and multipotent capacity, which were seen in NSCs and were capable of differentiating into neuron and glial cell types. The SGN spheres derived from mice at an early age (postnatal day or 2 weeks) contained more mitotic stem cells than those from mice at a late age. Conclusion. Our findings showed the presence of self-renewing and proliferative subtypes of SGN-NSCs which might serve as a promising source for the regeneration of auditory neurons even in adult mice.

• 동의신경정신과학회지
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• 제18권1호
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• pp.95-110
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• 2007

Objective : The purpose of this study was to investigate molecular basis of neuroprotective effect in total ginsenosides. After H202 induced neurotoxicity, gene expression profiling of SH-SY5Y neuroblastoma cells treated by total ginsenosides is analyzed. Method : After SH-SY5Y cells were cultured, they were damaged by H202 induced oxidative stress. After twenty four hours, experimental group is treated by total ginsenosides and control group is treated by 0.9% saline. A high density cDNA microarray chip is used to analyze the gene expression profiling of SH-SY5Y cells. The Significance Analysis of Microarray method is used for identifying genes on a microarray. Results : 1. According to the results of microarray experiment, 17 genes were up-regulated, 38 genes were down-regulated. 2. Expression of OPHNl, KTANl, ATM, PRKCE, MAPKs genes associated with cell proliferation, neural growth, and the prevention of apoptosis were increased. 3. Change of EPX gene was the greatest among all genes. EPX gene associated with oxidative stress, and tumor suppressor gene ADAM11 were decreased. Conclusion : According to this study, molecular basis of neuroprotective effect of total ginsenosides is as followings: the increase of gene expression associated with cell proliferation, neuron growth, the prevention of apoptotsis and decrease of gene expression associated with oxidative stress and tumor suppressor.

• 생명과학회지
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• 제19권4호
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• pp.449-456
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• 2009

신경아세포종은 미분화된 신경외배엽 세포로부터 유래한 신경능세포에 의해 형성된 소아기에 보는 가장 많이 발생하는 악성 종양 중 하나이다. 신경아세포종인 Neuro-2a 세포는 신경세포의 분화, 세포사 억제 효능, 세포독성 검정 등에 활용되고 있다. Neuro-2a 역시 다른 신경아세종과 같이 염색체 변이를 가지고 있지만, 이에 대해 고밀도의 게놈수준에서 염색체 변이에 대해 보고된 바가 없다. 본 연구에서는 고집적 마이크로어레이(최소 43,000 개의 코딩, non-코딩 유전자 서열이 집적된 마이크로어레이)기반의 비교유전체보합법을 활용하여, 고해상도의 Neuro-2a 유전체 이상을 분석하였다. 마이크로 어레이 데이터는 Hidden Markov Model을 활용하여, 유전체 변이를 double loss, single loss, normal, single gain 그리고 amplification으로 나누어 분석하였다. Neuro2a는 MYCN 유전자의 증폭은 관찰되지 않았고, GDNF, BDNF, NENF등의 neurotrophic factor 가운데 NENF의 gain 현상이 관찰 되었다. 염색체의 이상은 4,8,10,11,15번에서 발견되었으며, 염색체 3,17,18,19에서는 전부 20개 미만의 염색체 이상이 발견되었다. 염색체 이상이 연속적으로 일어난 부위 중 gain으로서 가장 긴 부분은 Chr8:8,427,841-35,162,415의 약 26.7 Mb이며, single loss로서 가장 긴 곳은 Chr4:73,265,785-88,374,165의 약 15.1 Mb였다. 염색체의 위치는 UCSC 데이터베이스 (UCSC mm8, NCBI Build 36)에 근거하였다.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.102-102
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• 2003

Embryonic stem (ES) cells proliferate extensively in the undifferentiated state and have the potential to differentiate into a variety of cell types in response to various environmental cues. The generation of functional dopaminergic neurons from ES cells is promising for cell replacement therapy to treat Parkinson's disease. We compared the in vitro differentiation potential of pluripotent human embryonic stem (hES, MB03) cells induced with basic fibroblast growth factor (bFGF) or retinoic acid (RA). Both types of treatment resulted in similar neural cell differentiation patterns at the terminal differentiation stage, specifically, 75% neurons and 11% glial cells. Additionally, treatment of hES cells with brain derived neurotrophic factor (BDNF) or transforming growth factor (TGF)- $\alpha$ during the terminal differentiation stage led to significantly increased tyrosine hydroxylase (TH) expression, compared to control (P<0.05). In contrast, no effect was observed on the rate of mature or glutamic acid decarboxylase-positive neurons. Immunostaining and HPLC analyses revealed the higher levels of TH (20.3%) and dopamine in bFGF and TGF-$\alpha$ treated hES cells than in RA or BDNF treated hES cells. The results indicate that TGF-$\alpha$ may be successfully used in the bFGF induction protocol to yield higher numbers of functional dopaminergic neurons from hES cells.

• 생명과학회지
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• 제30권11호
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• pp.939-946
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• 2020

뇌졸중은 전 세계적으로 신경계 장애를 일으키는 주요 원인 중 하나이며, 뇌졸중 환자는 다양한 운동, 인지 및 정신 장애를 나타낸다. GPR88은 orphan G protein coupled receptor이며 striatal medium spiny neurons에서 높게 발현이 되며, GPR88이 결손이 된 경우 motor coordination과 motor learning에 문제가 발생하게 된다. 본 연구에서는 Western blot 및 real-time PCR을 사용하여 허혈성 마우스 모델에서 GPR88 발현이 감소함을 발견 하였다. 또한, 뇌에서 유래한 세 가지 유형의 세포들, 뇌혈관내피세포(brain microvascular endothelial cells), 미세 아교세포(microglial cells) 및 신경 세포들에서 GPR88의 발현정도를 확인한 결과, HT22 신경 세포에서 GPR88의 발현이 가장 높음을 관찰하였고, 뇌졸중과 유사한 실험조건인 oxygen glucose deprivation (OGD) 조건에 배양한 HT22 신경세포에서 GPR88의 발현이 감소하였다. 또한 GPR88 효현제인 RTI-13951-33 (10 mg/kg)을 전처리후에 뇌허혈을 유발하였을 때, infarct volume의 감소, vestibular-motor function 및 neurological score의 개선효과를 관찰할 수 있었다. 이러한 결과는 GPR88이 허혈성 뇌졸중을 포함한 CNS 질환의 치료를 위한 잠재적인 약물표적이 될 수 있음을 제시한다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권5호
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• pp.525-531
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• 2008

CDH-13(T-cadherin), which is one of a kind among the 20 cadherins, can be found mainly in wall of aorta, neuron, spleen, blood vessel etc. It is also called H-cadherin. This structural difference can explain that CDH-13 is thought to play a key role in maintaining mutual relation between extra and intra-cellular environment rather than in cell adhesion. The main function of CDH-13 is to participate in blood vessel function. Additionally, it is known to regulate cell growth and cell contact inhibition. When cells are proliferating, cell surface perceives other cells so that substance such as CDH-13 can inhibit their growth or proliferation resulting in homeostasis without endless proliferation or invasion of connective tissue boundaries. However, tumor cell itself appears to be different from normal cells' growth, invasion or transmission. Therefore, it can be diagnosed that these characteristics are closely related to expression of CDH-13 in tumor cells. This study is to investigate expression of CDH-13 in SCC and its correlation with promoter methylation. 20 of tissue species for the study are excised and gathered from 20 patients who are diagnosed as SCC in department of OMS, dental hospital, dankook university. To find development of CDH-13 in each tissue samples, immunohistochemical staining, RT-PCR gene analysis and methylation specific PCR are processed. The results are as follows. 1.Immunohistochemical staining: In normal oral squamous epithelial tissue, strong expression of CDH-13 was found in cell plasma membrane of basal cell layer. On the other hand, in case of low-differentiated oral SCC, development of CDH-13 was hardly seen. 2.The development of CDH-13 gene: In 9 of samples, expression of CDH-13 gene could be seen and 2 of them showed low expression compared to the others. And rest of the 11 samples showed no expression of CDH-13 gene. 3.Methylation of CDH-13 gene: Among 9 samples which expressed CDH-13 gene, 7 of them showed unmethylation. In addition, among 11 samples without CDH-13 gene expression, 10 showed methylation. According to the results stated above, promoter methylation were found in 13 samples(65%) among 20 of oral SCC samples. In low-differentiated SCC, suppression of gene expression could be seen accompanying promoter methylation. These phenomenon of gene expression was proved by immunohistochemical investigation. Finally, for development of oral SCC, conclusions can be made that suppression of CDH-13 played a main role and suppression of gene expression was originated from promoter methylation. Considering this, it is expected that suppression of CDH-13 from promoter methylation to be utilized as a good diagnostic marker of oral SCC.