• 한국응용과학기술학회지
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• 제35권4호
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• pp.1433-1441
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• 2018

고강도 운동 시 산성화의 과정은 수소이온의 방출과 젖산 나트륨염을 형성하는 젖산의 생산 증가에 따른 것이라 설명되어져 왔다. 이 설명에 의하면, 젖산의 생산 비율이 세포내의 수소이온 완충능력을 초과하였을 때 세포의 수소이온 농도는 증가한다고 한다. 이러한 생화학적 과정을 젖산의 산성화라 한다. 이 이론에 따라 고강도 운동 시 젖산의 생산이 대사적 산성화와 피로의 원인이 되는 것으로 해석되어져 왔다. 그러나, 본 고찰에서는 젖산의 생산이 산성화와 피로의 원인이라는 어떠한 생화학적 근거가 없음을 명확히 제시하고 있다. 오히려 젖산의 생산은 해당과정에서 필요한 $NAD^+$의 지속적인 공급을 위해 필수적이며 수소이온을 소비하는 대사과정이다. 젖산의 축적은 세포와 혈중의 수소이온 농도의 증가를 알려주는 좋은 지표가 될 수는 있지만 그것이 산성화의 직접적인 원인은 아니다.

• International Journal of Oral Biology
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• 제45권4호
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• pp.190-196
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• 2020

Several factors, including genetic and environmental insults, impede protein folding and secretion in the endoplasmic reticulum (ER). Accumulation of unfolded or mis-folded protein in the ER manifests as ER stress. To cope with this morbid condition of the ER, recent data has suggested that the intracellular event of an unfolded protein response plays a critical role in managing the secretory load and maintaining proteostasis in the ER. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and hydrophilic bile acid that is known to inhibit apoptosis by attenuating ER stress. Numerous studies have revealed that TUDCA affects hepatic diseases, obesity, and inflammatory illnesses. Recently, molecular regulation of ER stress in tooth development, especially during the secretory stage, has been studied. Therefore, in this study, we examined the developmental role of ER stress regulation in tooth morphogenesis using in vitro organ cultivation methods with a chemical chaperone treatment, TUDCA. Altered cellular events including proliferation, apoptosis, and dentinogenesis were examined using immunostaining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, altered localization patterns of the formation of hard tissue matrices related to molecules, including amelogenin and nestin, were examined to assess their morphological changes. Based on our findings, modulating the role of the chemical chaperone TUDCA in tooth morphogenesis, especially through the modulation of cellular proliferation and apoptosis, could be applied as a supporting data for tooth regeneration for future studies.

• Molecules and Cells
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• 제38권7호
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• pp.643-650
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• 2015

The use of conditioned medium from mesenchymal stem cells may be a feasible approach for regeneration of bone defects through secretion of various components of mesenchymal stem cells such as cytokines, chemokines, and growth factors. Mesenchymal stem cells secrete and accumulate multiple factors in conditioned medium under specific physiological conditions. In this study, we investigated whether the conditioned medium collected under hypoxic condition could effectively influence bone regeneration through enhanced migration and adhesion of endogenous mesenchymal stem cells. Cell migration and adhesion abilities were increased through overexpression of intercellular adhesion molecule-1 in hypoxic conditioned medium treated group. Intercellular adhesion molecule-1 was upregulated by microRNA-221 in mesenchymal stem cells because microRNAs are key regulators of various biological functions via gene expression. To investigate the effects in vivo, evaluation of bone regeneration by computed tomography and histological assays revealed that osteogenesis was enhanced in the hypoxic conditioned medium group relative to the other groups. These results suggest that behavioral changes of endogenous mesenchymal stem cells through microRNA-221 targeted-intercellular adhesion molecule-1 expression under hypoxic conditions may be a potential treatment for patients with bone defects.

• Applied Microscopy
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• 제32권3호
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• pp.275-284
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• 2002

두꺼비 등 피부손상 후 과립선의 재생과정을 주사전자현미경과 투과전자현미경으로 관찰하였다. 절개에 의하여 피부손상을 가한 후 실험을 위하여 특수히 제작된 cage 내에서 최대 20일간 사육하였다. 투과전자현미경 관찰에서 손상 4일 후 미성숙 형태의 신생 과립선이 관찰되었으며, 상피세포는 신생 과립선의 첨단부로 이동하여 있었다. 상피세포의 표면은 편평하였으며 desmosome 에 의해 서로 연결되어 있지 않았다. 미토콘드리아를 많이 함유한 세포돌기 (MRC)들이 선의 내강을 형성하고 있었고, 이들 돌기에서는 hemidesmosome이 관찰되었다. 신생선의 기저강은 MRC, 과립형성전세포 및 과립형성 세포 등으로 이루어져 있었다. 특히, 손상 후 10일에 xanthophore가 상피세포의 기저부로 이동하여 있음이 관찰되었다. 이들 세포는 다수의 크기가 큰 pterinosome 과 중등도의 전자밀도를 가진 carotenoid vesicle을 포함하고 있었다. 손상 후 13일에, xanthophore는 많은 carotinoid vesicle과 lammelated pterinosomes을 포함하고 있었다. Iridophore는 손상 16일에 분화중인 xanthophore 주변에서 관찰되었다. 이러한 소견은 손상으로부터의 회복 과정에 선조세포(glandular precursor cell)로부터 과립선이 재생되며, 선세포의 팽대는 이들 신생 세포의 성숙 및 증식에 의한 것을 의미한다.

• Molecules and Cells
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• 제23권3호
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• pp.323-330
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• 2007

The mature wheat embryo is arguably one of the best explants for genetic transformation because of its unlimited availability and lack of growth season restriction. However, an efficient regeneration system using mature wheat embryos (Triticum aestivum L.) is still not available. To identify genes related to the tissue culture response (TCR) of wheat, QTLs for callus induction from mature embryos and callus regeneration were mapped using an RIL population derived from the cross of 'Wangshuibai' with 'Nanda2419', which has a good TCR. By whole genome scanning we identified five, four and four chromosome regions conditioning, respectively, percent embryos forming a callus (PEFC), percent calli regenerating plantlets (PCRP), and number of plantlets per regenerating callus (NPRC). The major QTLs QPefc.nau-2A and QPcrp.nau-2A were mapped to the long arm of chromosome 2A, explaining up to 22.8% and 17.6% of the respective phenotypic variance. Moreover, two major QTLs for NPRC were detected on chromosomes 2D and 5D; these together explained 51.6% of the phenotypic variance. We found that chromosomes 2A, 2D, 5A, 5B and 5D were associated via different intervals with at least two of the three TCR indexes used. Based on this study and other reports, the TCRs of different explant types of wheat may be under the control of shared or tightly linked genes, while different genes or gene combinations may govern the stages from callus induction to plantlet regeneration. The importance of group 2 and 5 chromosomes in controlling the TCRs of Triticeae crops and the likely conservation of the corresponding genes in cereals are discussed.

• 공업화학
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• 제19권3호
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• pp.326-331
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• 2008

본 연구의 목표는 고체기질 표면에 Na 이온이 포함된 비양론적 인회석 코팅을 형성하는 기술을 개발하는 것이다. 나트륨염 농도가 다른 조건에서 형성된 인회석 코팅은 Na 이온이 존재하는 경우 표면 morphology, 화학적 상태 그리고 Ca/P 비율 등에 상당한 영향을 미치는 것으로 나타났다. 이러한 성질들의 변화는 Na 이온의 농도가 0.01 mM로 증가될 때까지 지속되었다. 칼슘과 인의 비율은 2.18에서 2.03 정도까지 변화되었으며, 이는 합성된 비양론적 인회석이 칼슘이 풍부한 조성을 가지고 있음을 나타내고 있다. 모든 시료들의 구조는 저결정성 구조를 갖는 것으로 나타났다. 인회석 코팅층 내에 Na 이온이 존재하는 경우, 인간 조골세포의 세포주인 SaOS-2 세포의 부착이 상당히 증가하였다. 그러나 이 세포들의 증식은 Na 이온 농도가 증가함에 따라 감소하는 것으로 나타났다. 이러한 상반된 세포반응은 SaOS-2 세포와 인회석 표면간의 작용이 세포신호전달을 포함한 세포내 기전에 상당한 변화를 초래했기 때문일 것으로 사료된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.78-78
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• 2016

For the past three decades, extensive research has been performed in the surface design of new polymers for a variety of medical applications. Great progress in therapeutics and diagnostics can be attributed to these scientific advances in biomedical polymers. A variety of bioinert materials or bioactive materials using drugs, cells, and growth factors are widely utilized for the implants, devices and tissue regeneration. These materials provide an improved biocompatible materials to host, to significantly decrease or increase the host/tissue/blood response to the foreign materials. In the future, biomaterials will play a different role in modern therapeutics. New materials will be tailored to interact more on a protein and cellular level to achieve high degree of biocompatibility, biospecificity and bioacitivity. In this presentation, various biocompatible materials based on surface/bulk engineering will be demonstrated, which can be utilized as therapeutics implants and therapeutic vehicles for biologically active molecules such as cell, protein /peptide and gene.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.2.2-2.2
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• 2011

The central strategy in tissue engineering involves a biomaterial scaffold as a delivery carrier of cells and a depot to deliver bioactive molecules. The ability of scaffolds to control cellular response to direct particular repair and regeneration processes is essential to obtain functional tissue engineering constructs. Therefore, many efforts have been made to understand local interactions of cells with their extracellular matrix (ECM) microenvironment and exploit these interactions for designing an ideal scaffold mimicking the chemical, physiological, and structural features of native ECM. ECM is composed of a number of biomacromolecules including proteins, glycosaminoglycans, and proteoglycans, which are assembled together to form complex 3-dimensional network. Electrospinning is a process to generate highly porous 3-dimensional fibrous structure with nano to micro scaled-diameter, which can closely mimic the structure of ECM. In this presentation, our approaches to develop biomimetic electrospun fibers for modulation of cell function will be discussed.

• Biomolecules & Therapeutics
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• 제18권4호
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• pp.351-362
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• 2010

Nitric oxide (NO), synthesized from L-arginine by three isoforms of NO synthase (NOS), is a gaseous signaling molecule with an astonishingly wide range of biological and pathophysiological activities, including vasorelaxation, angiogenesis, anti-inflammation, and anti-apoptosis in mammalian cells. Recent studies have shown that NO donors and inhaled NO convert to biologically active NO under biological conditions and act as a signaling molecule in pathophysiological conditions. This review will discuss the roles of NO and its potential therapeutic implication in various human diseases, such as tumor, vascular regeneration, hypertension, wound healing, and ischemia-reperfusion injury.

• 한국동물생명공학회지
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• 제34권2호
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• pp.70-74
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• 2019

The kidney is a highly complex organ, and acute or chronic renal diseases can occur with various complications such as diabetes and hypertension. So far, no target specific treatment is available in acute or chronic renal failure, necessitating the development of alternative therapeutic strategy. Recent experimental findings suggest that the renal function and structure can be restored after being treated with various sources of stem/progenitor cells. In this review, we discuss up-to-date findings of the potential of renal progenitor/stem cells in alleviating renal injuries with a focus on preclinical studies. We also review cellular mechanisms underlying the therapeutic function of these cells.