The stem cell research is emerging as a cutting edge topic for a new treatment for many chronic diseases. Recently, dental stem cell would be possible for regeneration of tooth itself as well as periodontal tissue. However, the study of the cell characterization is scarce. Therefore, we performed the genetic profiling and the characterization of mouse fetus/neonate derived dental tissue and cell to find the identification during dental development. We separated dental arch from mandibles of 14.5 d fetal mice and neonate 0 d under the stereoscope, and isolated dental cells primarily from the tissues. Then, we examined morphology and the gene expression profiles of the primary cells and dental tissues from fetus/neonate and adult with RT-PCR. Primary dental cells showed heterogeneous but the majority was shown as fibroblast-like morphology. The change of population doubling time levels (PDLs) showed that the primary dental cells have growth potential and could be expanded under our culture conditions without reduction of growth rate. Immunocytochemical and flow cytometric analyses were performed to characterize the primary dental cell populations from both of fetus (E14.5) and neonate. Alpha smooth muscle actin (α-SMA), vimentin, and von Willebrand factor showed strong expression, but desmin positive cells were not detected in the primary dental cells. Most of the markers were not uniformly expressed, but found in subsets of cells, indicating that the primary dental cell population is heterogeneous, and characteristics of the populations were changed during culture period. And mesenchymal stem cell markers were highly expressed. Gene expression profile showed Wnt family and its related signaling molecules, growth factors, transcription factors and tooth specific molecules were expressed both fetal and neonatal tissue. The tooth specific genes (enamelin, amelogenin, and DSPP) only expressed in neonate and adult stage. These expression patterns appeared same as primary fetal and neonatal cells. In this study we isolated primary cells from whole mandible of fetal and neonatal mice. And we investigated the characteristics of the primary cells and the profile of gene expressions, which are involved in epithelial-mesenchymal interactions during tooth development. Taken together, the primary dental cells in early passages or fetal and neonatal mandibles could be useful stem cell resources.

The Chinese Hamster Ovarian cells CHOK1 are one of the most extensively used cells for the evaluation of gene expression and toxicology. However, these cells are frequently used for biomedical research without consideration of their cytogenetic characteristics. Therefore, we carried out to investigate the karyologic profiles, the frequency and type of chromosome aberration, and the distribution of telomeric DNA on chromosomes of the CHOK1 cells. The GTGbanding and fluorescence in situ hybridization on CHOK1 cells were performed to characterize the karyotype and the distribution of telomeric DNA. The present study revealed that the chromosome modal number of CHOK1 cells was 2n=20; eight chromosomes appeared to be identical with those of the normal Chinese hamster, whereas the remaining 12 chromosomes were shown to be translocated, deleted, inversed, or rearranged from Chinese hamster chromosomes. The telomeric DNA on CHOK1 chromosomes was intensively distributed at the centromeres rather than the ends of chromosomes. In addition, three chromosomes had interstitial telomeres and one marker chromosome entirely consisted of telomeric DNAs. The frequency and type of chromosome aberrations in CHOK1 cells were examined. Of the 822 metaphase spreads, 68 (8.3%) cells resulted in chromosome aberrations of which the chromosome breakage was the most frequently occurred.

본 논문의 연구목적은 Choroidal neovascularization (맥락막 신생혈관) 모텔에서 HO-1 발현제와 억제재의 영향을 알아보고자 한다. 30마리의 Brown Norway rat을 각각 10마리씩 세 그룹， Hemin treated group, SnPP treated group, Contorl group으 로 나누어서 실험을 진행하였다. Hemin treat group은 10μmol/kg hemin(Frontier Scientific Inc. USA) 을 SnPP treat group은 10 μmol/kg SnPP(Frontier Scientific Inc. USA)을 laser 시술 2 일에서 14 일까지 복강내 주사하였고 Control군은 0.5 mß씩 식 염 수를 주사하였다. 14 일 후 안저사진촬영과 형광안저촬영을 실시하였다. SnPP treated group에서 Hemin treated group보다 더 많은 선생혈관이 생성되었다. Hemin treated group에서는 맥락막 신생혈관 형성의 정도가 정상대조군에 비교하여 저하됨을 알 수 있었다. 본 연구의 결과 HO-1 의 inducer 인 Hemin 이 맥락막의 신생혈관 억제에 영향을 미치는 것으로 보여진다.

It has been reported that light-emitting diodes(LED) can be used in the treatment of oral diseases. Although bio-stimulatory effects of LED irradiation such as promotes stimulation of wound healing have been well known, there are few reports about molecular mechanism associated with cell cycle by LED irradiation. The purpose of present study was to examine the molecular event in cell cycle of LED irradiation on primary human gingival fibroblast(hGF) in vitro. The source of light for irradiation was a continuous-wave LED emitting at a wavelength of 635nm, and manufactured that energy density was 5mW/cm2 on sample surface. The hGF were irradiated for 1 hour at 37℃ in 5% CO2 humidified chamber. Experimental samples were acquired at 0 (right after irradiation), 8 and 24 hour after irradiation. To investigate the molecular mechanisms associated with cell cycle, growth phase was determined by flow cytometry and mRNA expression of cyclin A, cyclin B, cyclin D1, cyclin E, cdc2, PCNA, p18, p27, p21, and p53 were determined by real time RT-PCR. Flow cytometric analysis demonstrated the percentage of cells in the G1 and S phase were decreased, but the G2 phase increased, which showed cells irradiated by LED were transitioned from S to G2 phase. For mRNA expression, cyclin B, cdc2, PCNA and p53 were increased at 0 hour after irradiation, and most of cell cycle molecules were increased at 8 hour after irradiation. At 24 hour after irradiation, cyclin A, cyclin E, PCNA and p18 were increased. Taken together, LED irradiation induced proliferation of hGF cells through transition from S to G2 phase.

뻐ny studìes have shown the anti-proli ferative effects of irondeprivation on cancer cell s‘ but the effects 01' iron-chelators on oral cancer have not been clearly elucidated , To investigate the effects of an iron chelato r, desferrioxamine( 01"O).on the growth of ilIllTIortali zed human o1'al ke ratinocytes(IHOK), primary oraJ cancer cel ls(HN4)‘ metastatic oral cancer cell s(HN12) , and human skin keratìnocytes(HaCaT) in the MTr assay, three-dimensional(3D) raft cul tmes, Western blott ing, cell cycJ e analysis‘ nuclear staining‘ and cytochrome c expression for apoptosis s ig naling pathway were used OFO inhibited the growth of immortalized IHOK and HaCaT and mal ignant HN4 and HN12 keratinocytes in a time- and dose-dependent manner according to the MTT assay, The 3D organotypic cu l tu re also revealed that OF'O-treated cells showed less epithelial maturation, less surface keratinizati on‘ and de creased epithelia l thickness, The major mechanìsm of growth inhìbition with the micromolar 0 1"0 treatment was by the induction of apoptosis‘ which was supported by nuclear OAPI staining, ONA fragmentation analysis, and J10w cytometric analysis for sub-Gl phase ar rest and Annexin V-1"ITC stainìng, Furthermore‘ Bax expression in creased together with p53 and p21WAF1!CIPl, whìle the Bcl-2 expression decreased in the immortalized and malig nant keratinocytes treated with 01"0 , Time-dependent cytochrome c from mitochondria was observed in D1"O-treated [l-IOK and 0 1'머 cancel‘ ceJJ s, and was accompanied by the activation of caspase-3 in IHOK cells. These resu lts demonstrate that 0 1"0 has growth inhibitory effects on immortalized and malignant oral keratinocyLes Lhrough the induction of apoptosis and suggest that further evaluation of OFO as a potcntial thcrapcutic agent for human oral precancerous and cancerous lesions is warranted

본 논문에서는 핫셀에서의 원격 운전 및 유지보수 작업을 위해 개발한 천정이동 서보 조작기시스템에 대해 소개한다. 조작기 시스템은 텔레스코픽형 이송장치, 슬레이브, 마스터, 그리고 제어시스템으로 구성되어 있다. 개발한 시스템에 대해 위치 추종, 하중 취급, 신뢰성, 및 조작성에 대한 테스트를 수행하였으며 이에 대한 테스트 결과를 제시한다. 이러한 테스트 결과를 바탕으로 개선된 시스템 이 설계되었으며 이 개선된 시스템 이 차세대 공정의 실증에 적용될 예정이다.