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        검색결과 1,648

        921.
        2005.09 구독 인증기관 무료, 개인회원 유료
        Bone morphogenetic proteins (BMPs), members of a large group of TGF-beta family, are important molecular regulators of morphogenesis of numerous tissues and organs, including bones and teeth. Most BMPs are capable of inducing bone formation in vivo and therefore are of considerable clinical interest for regenerating mineralized tissues. Recently, we have developed a method to culture cells from human cementum (human cementum-derived cells, HCDCs). HCDCs, when attached to synthetic hydroxyapatite/tricalcium phosphate (HA/TCP) ceramic and transplanted into immunodeficient mice, formed histologically identifiable cementum-like tissue. Since it is unclear to what extent BMPs are involved in cementogenesis, the aim of this study was to establish which BMPs are expressed by cementogenic HCDCs and whether the expression of BMPs is related to the degree of cellular differentiation in vitro. HCDCs were maintained in growth medium (DMEM/F12 supplemented with 10% FBS) until confluent (proliferation stage). Upon reaching confluence, cells were incubated in the differentiation medium (DMEM/F12 medium containing 10% FBS and 50 mg/ml ascorbic acid) for 14 days (differentiation stage). Next, HCDCs were incubated in mineralization medium (DMEM/F12, 50 mg/ml ascorbic acid, 2.5 mg/ml of ITS (insulin-transferrinselenium), 5 mM beta-glycerophosphate and 10­⁻8 Mdexamethasone) for another 14 days (mineralization stage). At the end of each differentiation stage, total RNA was isolated and evaluated for BMPs (2 through 8) expression by employing real time RT-PCR. HCDCs expressed most of BMPs examined except BMP-7 and BMP-8. Furthermore, on average, the highest levels of BMPs were expressed at the earlier differentiation stage, prior to the initiation of mineralization in vitro. These results indicate that several BMPs are expressed during cementoblastic differentiation and suggest that BMPs may be involved in the homeostasis of human cementum.
        4,000원
        922.
        2005.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        유학은 인간의 심성(心性)에 대한 탐구를 2,000여 년에 거쳐 해온 학문분야이다. 따라서 유학에서의 인간의 심성에 대한 관점과 연구방법은 현대의 감성과학에 적용될 가능성이 매우 높다. 유학에서의 인간심성을 유학의 전반적 개념과 퇴계 이황의 개념으로 고찰하여본 결과 현대의 감성과 유사한 정(情)이라는 개념이 있었으며, 본 마음(性)의 발로의 결과인 정의 좋음과 나쁨의 관점은 정이 발현되는 과정에서 좋은 정과 나쁜 정으로 구분된다고 하여 정의 형식이 중요한 것이 아니라 인간의 본성이 왜곡됨 없이 발현된 정이 좋은 정, 즉 감성이라 하고 있어 현대의 감성의 호악과는 다른 기준을 가지고 있었음을 알 수 있었다 또한 심성을 파악하는 구조는 심성작용이 일어나는 형식구조로 파악하고 있는 것이 아니라 심성의 내용과 작용주체를 파악하기 위한 관점으로 파악하고 있음도 알 수 있었다. 또한 현재의 인지, 감성, 생리, 철학 등의 관점이 총체적 ·종합적인 관점으로 인간의 심성을 바라보고 있음을 알 수 있었다. 연구의 종합결론으로서는 유학에서도 인간의 심성을 탐구하기 위한 연구가 매우 오랜 기간 수준 높게 진행되었으며, 현재 감성과학에 부분적인 참고와 도움뿐만이 아니라 감성과학의 지향점을 찾는 데 중요한 관점과 지식을 충분히 제공할 수 있을 것이라는 알 수 있었다.
        4,200원
        923.
        2005.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to investigate the cytotoxicity of dental casting gold alloys. Recently, "biocompatability" is considered the most important requirement of dental materials. Dental metals and alloys were estimated by quantity of released ions, which had influenced to living tissues. The requirement of using normal human cells for cytoxicity strudy were abruptly increased. We used the cultured normal human gingival fibroblasts to estimate the cytotoxicity of dental casting gold alloys. The product of S company(Korea, AIGIS-SOFT, AIGIS-PLUS, AIGIS-A, AIGIS-PT, experimental group) and D company's (German, Biocclus inlay, Biolor SG, Stabilor NF Ⅳ, Degulor B, control group) dental casting gold alloys were used. The morphological investigation, hemolysis test, MTT assay and SRB assay were done in vitro. In vivo, inflammatory reaction in rat was examined for 2 weeks. 1. In the result of cytotoxicity assay, there were some differences but was no significancy among the results between two group's hemolysis, MTT and SRB assay. 2. The gingival fibroblasts attached to the surface of dental casting gold alloy showed various features and increased in number as the time had passed. 3. In vivo, chronic inflammatory cell infiltration was prominent from 3 days to 1 week and inflammation was reduced as time had gone. From the aboving results, there were no significant differences in cytoxicity depending on the ratio of gold content, but showed differences depending on the ratio of total precious and non-precious metal content between two groups. In vitro study showed few differences in inflamation reaction.
        4,300원
        924.
        2005.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Studies to evaluate distribution of markers in normal keratinocyte and their immortalized keratinocyte are appropriate to evaluate the normal and preneoplastic lesion of oral cancers as biochemical and cytochemical changes associate with tumorigenesis being not completely understood. Complementary DNA microarray containing 6000 sequence -verified cDNA elements was used to systematically characterize the variation in gene expression patterns of NHOK cells vs. immortalized keratinocyte by HPV16 E6-E7(IHOK). Examination of gene expression that is 85 clones cDNAs exhibits greater than 2 fold overexpression in NHOK probes relative to IHOK probe, 147 cDNAs reveal greater 2 fold overexpression in IHOK relative to NHOK probe.The high similarity in gene expression (96.5%) between IHOK and NHOK cells suggests that only an additional 232/6720 (3.5%) of the genome is differentially gene activated during HPV16 immoratlized keratinocyte growth and differentiation. Examination of gene expression that differs between NHOK and IHOK cellsapprear to be related to : cell adhesion & recognition, cell cycle regulator, apoptosis, transciption factors, growth factors and therir receptors, cytoskeletal and extracellular matrix proteins, signal transduction modulators and effectors, and miscellaneous. The gene expression of cell recognition factor such as endothelin 1, collagen IV, fibronectin, and SPR1 in IHOK were upregulated. Distinct or duplicated cDNA clones representing the same gene were typically clustered in adjacent rows in the clustered gene map. Therefore the differentially expressed and identified genes should be informative in studying oral epithelial cell carcinogenesis and such studies should foster the research of molecular markers allowing to assess the phenotypeof malignant epithelial tumor.
        4,300원
        925.
        2005.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        대공간의 쇼핑몰, 오피스 등과 같이 낮은 고유진동수를 가지는 구조물들은 사람의 활동에 의하여 큰 동적응답이 발생할 수 있다. 이러한 활동은 한 사람의 경우보다는 여러 사람에 의한 경우가 더 일반적이다. 본 연구의 목적은 구조물의 모드형상을 이용하여 보행자 전용 구조물과 같이 무리하중을 받는 구조물의 응답을 간단하게 평가하는 것이다. 이를 위하여 사람간의 상관관계가 고려된 무리하중을 받는 구조물의 응답에 관한 식을 유도하였다. 그리고 무리하중을 구성하는 개개의 하중의 연관성을 파악하기 위하여 두 개의 로드셀을 이용하여 하중간의 상관관계를 조사하였다. 구조물의 모드와 하중간의 상관관계에 대한 식을 이용하여 무리하중에 의한 응답을 구조물의 모드형상만으로 평가하는 방법을 제시하였다. 이 방법의 효율성을 확인하기 위하여 보와 바닥판의 예를 들어 무리하중을 동조시킨 경우와 그렇지 않은 경우에 대하여 응답을 평가하였으며 마지막으로 실제 사용중인 구조물을 대상으로 무리하중을 동조시킨 경우와 그렇지 않은 경우에 대하여 응답을 계측하고 이를 제시한 방법과 비교하였다
        4,000원
        928.
        2005.06 구독 인증기관 무료, 개인회원 유료
        Human embryonic stem cells (hESCs) derived from the inner cell mass of blastocysts have the ability to renew themselves and to differentiate into cell types of all lineage. The present study was carried out to investigate whether the Wnt signaling pathway is related to maintaining self-renewal of hESCs. Glycogen Synthase Kinase 3 (GSK-3) inhibitor, BIO ((2''Z,3''E)-6-Bromoindirubin-3''-oxime) was treated to Miz-hES1 line for activation of Wnt signaling pathway. BIO-nontreated hESCs (control) and BID-treated hESCs were cultured for 5 days in the modified feeder-free system. During the culture of hESCs, differences were observed in the colony morphology between 2 groups. Controls were spread outwards whereas BIO-nontreated hESCs were clumped in the center and the differentiated cells were spreading outwards in the edges. The results of stem cell specific marker staining indicated that control were differentiated in large part whereas BIO-treated hESCs maintain self-renewal in the center of the colony. The results of lineage marker staining suggested that outer cells of the hESC colony were differentiated to the neuronal progenitor cells in both control and BIO-treated hESC. These results indicate that Wnt signaling is related to self-renewal in hESCs. In addition, control group showed higher composition of apoptotic cells (23.76%) than the BID-treated group (5.59%). These results indicate that BIO is effective on antapoptosis of hESCs.
        4,000원
        929.
        2005.06 구독 인증기관 무료, 개인회원 유료
        The hematopoietic growth factor erythropoietin (EPO) is required for the maintenance, proliferation, and differentiation of the stem cells that produce erythrocytes. To analyse the biological activity of the recombinant human EPO (rec-hEPO), we have cloned the EPO cDNA and genomic DNA and produced rec-hEPO in the CHO cell lines. The growth and differentiation of EPO-dependent human leukemic cell line (F36E) were used to measure cytokine dependency and in vitro bioactivity of rec-hEPO. MIT assay values were increased by survival of F36E cells at 24h or 72h. The hematocrit and RBC values were increased by subcutaneous injection of 20 IU (in mice) and 100IU(in rats) rec-hEPO. Hematocrit values remarkably increased at 13.2% (in mice) and 12.2% (in rats). The pharmacokinetic behavior with injection of 6 IU of rec-hEPO remained detectable after 24 h in all mice tested. The highest peat appeared at 2h after injection. The long half-life of rec-hEPO is likely to confer clinical advantages by allowing less frequent dosing in patients treated for anemia. These data demonstratethat ree-hEPO produced in this study has a potent activity in vivo and in vitro. The results also suggest that biological activity of ree-hEPO could be remarkably enhanced by genetic engineering that affects the potential activity, including mutants with added oligosaccharide chain and designed to produce EPO-EPO fusion protein.
        4,000원
        930.
        2005.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cervical carcinoma is the 1st most common malignancy in korean females. HPV have been strongly linked to progression of cervical carcinoma. E6 and E7 as a small DNA virus encoding two major oncoproteins of HPV can act together to produce efficient immortalization of primary human epithelial cells, providing further evidence for the role of HPV in tumorogenesis. It is important to pursue the development of Immortalized human epithelial keratinocyte(IHEK) culture model which could be related to the pathogenesis between cervical and oral carcinoma. If we establish IHEK transfected by E6E7 gene, IHEK will be accepted as a model system for HPV-linked cervical carcinogenesis. The purpose of this study were to culture primarily normal human epithelial keratinocyte(NHEK), and to establish IHEK for applying these results to cervical and oral carcinogenesis in the future. The obtained results were as follows. 1. After 7-9 passages, cultured NHEK was almost senesce and disappeared, but cultured IHEK showed most basal cell and monolayer of polyhedral cells under 0.05mM Ca++, while small area of stratification and flattened epithelial cells with irregular border under 1.2mM Ca++. 2. The cultured IHEK showed relatively resistant growth to high calcium condition. 3. The mRNA E6E7 in cultured IHEK by RT-PCR was detected. 4. During the terminal defferentiation in cultured NHEK and IHEK, increase of insoluble cornified cell envelope formation was accompanied with induction of TGase 1 activity. But the cultured IHEK showed less CEM and TGase 1 activity than those of cultured NHEK. 5. Cultured IHEK showed non-tumorogenecity, but week anchorage independence. From the aboving results, we have developed technique to transform NHEK into IHEK by transfecting cells with E6E7 gene. Cultured IHEK was established as intermediate stage cell for studying the pathogenesis of human cervical carcinoma.
        4,200원
        931.
        2005.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ionizing radiation is a well- known therapy factor for human carcinoma cells. Genotoxic stress mediates cell cycle control, transcription and cellular signaling. In this work, we have used a microarray hybridization approach to characterize the cell type-
        4,000원
        933.
        2005.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The present study investigated the hypothesis that a extremely low frequency magnetic field (ELF-MF) partially suppresses the synthesis of human growth hormone (HGH) in a group of 28 primary schoolchildren living nearby and 60 primary schoolchildren aged 12 years living far away from overhead transmission power lines from December 2003 to April 2004 in Seoul, Korea. The mean personal exposure levels of the primary schoolchildren living nearby overhead transmission power line were 0.37 μT, whereas the levels for the primary schoolchildren living away from overhead transmission power line was 0.05 μT. From simple analyses, the mean growth hormone levels in the primary schoolchildren living nearby were lower than away from overhead transmission power line, and statistically significant differences in the levels of the growth hormone (p = 0.0316), whereas not statistically significant differences in the levels of the growth hormone related to the distance from residence to power line less and more than 100 m by cut-off point (p = 0.4017). In conclusion, these results may indicate that urinary levels of nocturnal growth hormone are altered in primary schoolchildren exposed to extremely low frequency magnetic field at overhead transmission power line.
        4,800원