• IMMUNE NETWORK
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• v.1 no.1
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• pp.87-94
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• 2001

Background: Cytokine-mediated ex vivo expansion has been proposed as a means of increasing the number of cord blood (CB) hematopoietic stem cells for transplantation. As well as stem cell number, stromal cells are necessary for functional maturation of hematopoiesis. The purpose of this study was to analyze the development of stromal cells during ex vivo expansion of CB $CD34^+$ cells. Methods : $CD34^+$ cells were purified from CB by magnetic bead selection. The levels of of interleukin-3, interleukin-$1{\beta}$, interleukin-6, granulocyte macrophagecolony stimulating factor and tumor necrosis factor-${\alpha}$ were measured in culture supernatants on 0, 1, 2, and 3 weeks, using ELISA techniques. CB $CD34^+$ cells were expanded in Iscoves modified Dulbeccos medium in the presence of several cytokines. The expression of E-selectin, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, platelet/endothelial cell adhesion molecule-1, von Willebrand factor, vimentin, and CD14 in newly developed stromal cells was examined by immunocytochemical method. Relevant extracellular matrix (ECM) proteins and proper cytokines were also assayed for the most suitable condition for expansion of stromal cells. Results: Several cytokines were found to have been produced by CB $CD34^+$ cells as well as bone marrow-derived $CD34^+$ cells. During ex vivo expansion of CB $CD34^+$ cells, stromal cells appeared in the culture by day 4 and expanded over the following 7-10 days before being confluent by day 2 1. These cells expressed surface markers characteristic of cells of endothelial lineage. Furthermore, these stroaml cells also expanded effectively when treated with thrombopoietin+flt-3 ligand+stem cell factor+leukemia inhibitory factor or 0.1% poly-L-lysine-coated wells. Conclusion: Stromal cells were developed during ex vivo expansion of CB $CD34^+$ cells and that this development could be enhanced further by treating the stromal cells with cytokines or ECM.

• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.835-845
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• 1998

Background: Silica-induced lung diseases is characterized by the accumulation of inflammatory cells at early stage and fibrosis in pulmonary parenchyma and interstitium at late stage. As a consequence of inflammation, silicosis is accompanied with the expansion of interstitial collagen and the formation of fibrotic nodule. In this process, several kinds of lung cells produce cytokines which can amplify and modulate pulmonary fibrosis. The alveolar macrophage is a potent source of proflammatory cytokines and growth factor. But in the process of silicotic inflammation and fibrosis, there are many changes of the kinetics in cytokine network. And the sources of cytokines in each phase are not well known. Method: 2.5 mg of silica was instillated into the lung of C57BL/6J mice. After intratracheal instillation of silica, the lungs were removed for imunohistochemical stain at 1, 2, 7 day, 2, 4, 8, 12 week, respectively. We investigated the expression of IL-1$\beta$, IL-6, TNF-$\alpha$ and TGF-$\beta$ in lung tissue. Results: 1) The expression of IL-6 increased from 1 day after exposure to 8 weeks in vascular endothelium. Also peribronchial area were stained for IL-6 from 7 days and reached the peak level for 4 weeks. 2) The IL-1 $\beta$ was expressed weakly at the alveolar and peribronchial area through 12 weeks. 3) The TNF-$\alpha$ expressed strongly at alveolar and bronchial epithelia during early stage and maintained for 12 weeks. 4) TGF-$\beta$ was expressed strongly at bronchial epithelia and peribronchial area after 1 week and the strongest at 8 weeks. Conclusion: The results above suggests IL-6, TNF-$\alpha$ appear to be a early inflammatory response in silica induced lung fibrosis and TGF-$\beta$ play a major role in the maintenance and modulation of fibrosis in lung tissue. And the regulation of TNF-$\alpha$ production will be a key role in modultion of silica-induced fibrosis.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.555-565
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• 2006

The purpose of the present study is to evaluate the biological stability of the zirconia/alumina composite abutment by histologic and radiographic examination in clinical cases. 17 partially edentulous patients (5 men and 12 women, mean age 47) were treated with 37 implants. The implants were placed following the standard two-stage protocol. After a healing period of 3 to 6 months, zirconia/alumina composite abutments were connected. All radiographs were taken using paralleling technique with individually fabricated impression bite block, following insertion of the prosthesis and at the 3-, 6-, 12 month re-examinations. After processing the obtained images, the osseous level was calculated using the digital image in the mesial and distal aspect in each implant. An ANOVA and t-test were used to test for difference between the baseline and 3-, 6-, 12 months re-examinations, and for difference between maxilla and mandible. Differences at P <0.05 were considered statistically significant. For histologic examination, sample was obtained from the palatal gingiva which implant functioned for 12 months. Sections were examined under a light microscope under various magnifications. Clinically, no abutment fracture or crack as well as periimplantitis was observed during the period of study. The mean bone level reduction(${\pm}standard$ deviation) was 0.34 rom(${\pm}\;0.26$) at 3-months, 0.4 2mm(${\pm}\;0.30$) at 6-months, 0.62 mm(${\pm}\;0.28$) at 12-months respectively. No statistically significant difference was found between baseline and 3-, 6-, 12-months re-examinations (p > 0.05). The mean bone level reduction in maxilla was 0.33(${\pm}0.25$) at 3-months, 0.36(${\pm}0.33$) at 6-months, 0.56(${\pm}0.26$) at 12-months. And the mean bone level reduction in mandible was 0.35(${\pm}0.27$) at 3-months, 0,49(${\pm}0.27$) at 6-months, 0.68(${\pm}0.30$) at 12-months. No statistical difference in bone level reduction between implants placed in the maxilla and mandible. Histologically, the height of the junctional epithelium was about 2.09 mm. And the width was about 0.51 mm. Scattered fibroblasts and inflammatory cells, and dense collagen network with few vascular structures characterized the portion of connective tissue. The inflammatory cell infiltration was observed just beneath the apical end of junctional epithelium and the area of direct in contact with zirconia/alumina abutment. These results suggest the zirconia/alumina composite abutment can be used in variable intraoral condition, in posterior segment as well as anterior segment without adverse effects.