• Restorative Dentistry and Endodontics
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• v.30 no.5
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• pp.423-430
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• 2005

Ameloblasts are responsible for the formation and maintenance of enamel which is an epithelially derived protective covering for teeth. Ameloblast differentiation is controlled by sequential epithelial-mesenchymal interactions. However, little is known about the differentiation and maturation mechanisms. OD314 was firstly identified from odontoblasts by subtraction between odontoblast/pulp cells and osteoblast/dental papilla cells, even though OD314 protein was also expressed in ameloblast during tooth formation. In this study, to better understand the biological function of OD314 during amelogenesis, we examined expression of the OD314 mRNA and protein in various stages of ameloblast differentiation using in-situ hybridization and immunohistochemistry. The results were as follows : 1. The ameloblast showed 4 main morphological and functional stages referred to as the presecretory, secretory, smooth-ended, and ruffle-ended. 2. OD314 mRNA was expressed in secretory ameloblast and increased according to the maturation of the cells. 3. OD314 protein was not expressed in presecretory ameloblast but expressed in secretory ameloblast and maturative ameloblast. OD314 protein was distributed in entire cytoplasm of secretory ameloblast. However, OD314 was localized at the proxiamal and distal portion of the cytoplasm of smooth-ended and ruffle-ended ameloblast. These results suggest that OD314 may play important roles in the ameloblast differentiation and maturation.

• Journal of Gastric Cancer
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• v.5 no.1
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• pp.40-46
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• 2005

Purpose: Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms of the gastrointestinal tract. GISTs are positive for the expression of c-Kit protein at immunohistochemistry, and their clinical presentations vary. This retrospective study was performed to evaluate the clincopathologic characteristics of GISTs and to define the prognostic factors. Materials and Methods: 40 patients who underwent a complete resection of a GIST during the period $1996\~2003$ at the Department of Surgery, Korea University College of Medicine, were studied. We divided them into low- and high-risk. groups by using tumor size and mitotic count: 23 cases were low risk, and 17 were high risk. Clinicopathologic features, immunohistochemical findings, and prognoses were compared between the low- and the high-risk groups. Results: The mean age of the 40 patients was $61.3\pm11.1$years, and the male-to-female ratio was 1：1.1. There was no significant difference in age and sex between the groups. A comparative analysis revealed tumor size, mitotic count, clinical symptoms, preoperative pathologic diagnosis, ulceration, and necrosis to be variables that had statistically significant differences between the high- and the low-risk groups. In the univariate analysis, tumor size, mitotic count, ulceration, necrosis, and abnormal endoscopic ultrasound findings were associated with disease-free survival, but in the multivariate analysis, mitotic activity was the only independent factor associated with disease-free survival. 8 patients had recurrences during the follow-up period, and four of them were treated with STI-571 (imatinib mesylate, $Gleevec^{(R)}$). The treated patients have survived until now; however, two of non-treated patients died from disease progression. Conclusion: Based on this study, tumor size, ulceration, and necrosis are significant factors affecting survival, and mitotic activity may be a useful prognostic marker. STI-571 may be used in an adjuvant setting because the drug has shown anticancer activity in patients with recurrence or metastasis.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.576-583
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• 2005

Tooth formation is a complex developmental process that is mediated through a series of reciprocal epithelial-mesenchymal interactions. Several signal pathways and transcription factors have been implicated in regulating molar crown development, but relatively little is known about the regulation of root development. It was reported that NFI-C knockout mice showed abnormal root formation with normal crown. The aims of this study are to elucidate how the NFI-C regulate the determine of root shape and odontoblasts differentiation. We carried out immunohistochemistry using cytokeratin to investigate the role of Hertwig's epithelial root sheath and DSPP mRNA in-situ hybridization to conform the nature of root dentin during root development in NFI-C knockout mice. Cytokeratin reacted with all the HERS cells and the continuity of cytokeratin positive cells between the HERS cells and enamel epithelium was lost in the cervical region both wild and K/O types. After root dentin deposition cytokeratin positive-HERS cells showed irregularity and loss of polarity in the cervical region in K/O type. DSPP mRNA was strongly expressed in odontoblasts of crown and root dentin in wild type mice, whereas expression of DSPP mRNA was restricted in odontoblast of crown dentin in the K/O type. During root formation in NFI-C knockout mice, HERS normally grow out of the crown but fail to induce odontoblast differentiation in root portion. These results suggest that NFI-C may play important roles in odontoblast differentiation during root dentin formation.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.253-263
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• 2002

Purpose : In order to understand in vivo radiation damage modifying of bFGF on jejunal mucosa, bone marrow and the effect of bFGF on the growth of transplanted mouse sarcoma 180 tumor in mice. Materials and Methods : Mice were treated with $6\;{\mu}g$ of bFGF at 24 hours and 4 hours before exposing to 600 cGy, 800 cGy and 1,000 cGy total body irradiation (TBI), and then exposed to 3,000 cGy local radiation therapy on the tumor bearing thigh. Survival and tumor growth curve were plotted in radiation alone group and combined group of bFGF and irradiation (RT). Histologic examination was performed in another experimental group. Experimental groups consisted of normal control, tumor control, RT (radiation therapy) alone, $6\;{\mu}g$ bFGF alone, combined group of $3\;{\mu}g$ bFGF and irradiation (RT), combined group of $6\;{\mu}g$ bFGF and irradiation (RT). Histologic examination was peformed with H-E staining in marrow, jejunal mucosa, lung and sarcoma 180 bearing tumor. Radiation induced apoptosis was determined in each group with the DNA terminal transferase nick-end labeling method ($ApopTag^{\circledR}$ S7100-kit, Intergen Co.) Results : The results were as follows 1) $6\;{\mu}g$ bFGF given before TBI significantly improved the survival of lethally irradiated mice. bFGF would protect against lethal bone marrow syndrome. 2) $6\;{\mu}g$ bFGF treated group showed a significant higher crypt depth and microvilli length than RT alone group (p<0.05). 3) The bone marrow of bFGF treated group showed less hypocellularity than radiation alone group on day 7 and 14 after TBI (p<0.05), and this protective effect was more evident in $6\;{\mu}g$ bFGF treated group than that of $3\;{\mu}g$ bFGF treated group. 4) bFGF protected against early radiation induced apoptosis in intestinal crypt cell but might have had no antiapoptotic effect in bone marrow stem cell and pulmonary endothelial cells. 5) There was no significant differences in tumor growth rate between tumor control and bFGF alone groups (p>0.05). 6) There were no significant differences in histopathologic findings of lung and mouse sarcoma 180 tumor between radiation alone group and bFGF treated group. Conclusions : Our results suggest that bFGF protects small bowel and bone marrow from acute radiation damage without promoting the inoculated tumor growth in C3H mice. Improved recovery of early responding normal tissue and reduced number of radiation induced apoptosis may be possible mechanism of radioprotective effect of bFGF.

• Journal of Veterinary Clinics
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• v.28 no.5
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• pp.486-496
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• 2011

A special mesenchymal tissue layer called perichondrium has a chondrogenic capacity and is a candidate tissue for engineering of cartilage. To overcome limited potential for chondrocyte proliferation and re-absorption, we studied a method of cartilage tissue engineering comprising chondrocyte-hydrogel pluronic complex (CPC) and cultured perichondrial cell sheet (cPCs) which entirely cover CPC. For effective cartilage regeneration, cell-sheet engineering technique of high-density culture was used for fabrication of cPCs. Hydrogel pluronic as a biomimetic cell carrier used for stable and maintains the chondrocytes. The human cPCs was cultured as a single layer and entirely covered CPC. The tissue engineered constructs were implanted into the dorsal subcutaneous tissue pocket on nude mice (n = 6). CPC without cPCs were used as a controls (N = 6). Engineered cartilage specimens were harvested at 12 weeks after implantation and evaluated with gross morphology and histological examination. Biological analysis was also performed for glycosaminoglycan (GAG) and type II collagen. Indeed, we performed additional in vivo studies of cartilage regeneration using canine large fullthickness chondrial defect model. The dogs were allocated to the experimental groups as treated chondrocyte sheets with perichondrial cell sheet group (n = 4), and chondrocyte sheets only group (n = 4). The histological and biochemical studies performed 12 weeks later as same manners as nude mouse but additional immunofluorescence study. Grossly, the size of cartilage specimen of cPCs covered group was larger than that of the control. On histological examination, the specimen of cPCs covered group showed typical characteristics of cartilage tissue. The contents of GAG and type II collagen were higher in cPCs covered group than that of the control. These studies demonstrated the potential of such CPC/cPCs constructs to support chondrogenesis in vivo. In conclusion, the method of cartilage tissue engineering using cPCs supposed to be an effective method with higher cartilage tissue gain. We suggest a new method of cartilage tissue engineering using cultured perichondrial cell sheet as a promising strategy for cartilage tissue reconstruction.

• Journal of Life Science
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• v.17 no.12
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• pp.1766-1770
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• 2007

We describe here a case of malignant mixed osteogenic tumor of the mammary gland with alveolar carcinomatous appreance. A firm, 2 to 2.5cm (in diameter) mass under the 5th nipple, showing the structure of extraosseous osteogenic sarcoma, was removed from the left 5th mammary gland of 12-year-old female dog. When investigated under the microscope, the osteoid material undergoing mineralization was surrounded by numerous scattered osteoblasts and a few osteoclastic cells throughout the osteoid tumorous stroma. The osteoid lesions were continuous with hypercellular myoepithelial cells of a very immature character with several mitotic figures. In addition, there were also carcinomatous tubules and alveoli, with invading cells into peripheral stroma, surrounded by myoepithelial cells in the mammary gland. In these lesions, emanating cords of tumor cells appear to be continuous with the myoepithelial cell layer of a duct. The presence of all these cell types suggests the existence of a common malignant origin, the stem cell being differentiated into epithelial carcinomatous and mesenchymal sarcomatous chondral and osteogenic tissues.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.394-406
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• 2019

The cellular senescence may be due to damage by the reactive oxygen species (ROS). This study has compared the antioxidant activity in the human cell lines of various origins, including 10S and 50S-derived normal skin fibroblasts, and 10S bone marrow, dental tissue and adipose-derived adult stem cells. After being exposed to $H_2O_2$, half inhibitory concentration ($IC_{50}$) values by cytotoxicity assay was significantly (P<0.05) lower in 50S-derived skin fibroblasts, than in 10S-derived skin fibroblasts and various adult stem cell lines. The cell population doubling time (PDT) and the cell frequency with high senescence associated-${\beta}$-galactose activity were remarkably increased in 50S-derived fibroblasts exposed to 50 ppm $H_2O_2$ for 7 days, than those of 10S-derived fibroblasts and various adult stem cell lines. Further, the expression level of antioxidant-related genes, glutathione peroxidase (GPX) and catalase (CAT), was investigated in 10S and 50S-derived skin fibroblasts, and 10S-derived various adult stem cells by reverse transcription polymerase chain reaction (RT-PCR). The expression level of GPX was higher in most of cell lines, compared to CAT, and a significantly (P<0.05) higher expression level of GPX was observed in 10S-derived skin fibroblasts and adult stem cell lines, compared to 50S-derived skin fibroblasts. We concluded that old-aged skin fibroblasts seemed to be less resistant against ROS than young-aged skin fibroblasts and adult stem cells.

• Journal of Life Science
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• v.29 no.6
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• pp.724-734
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• 2019

The present study investigated the cytotoxicity of particulate matter (PM) derived from car air filter (outdoor PM) and home cleaner filter (indoor PM) in the various human cell lines. Each outdoor and indoor PM were harvested by ethanol extraction method, subsequently sieved with 10 um filter paper, sterilized with autoclave and added to culture media. The half maximal inhibitory concentration ($IC_{50}$) values was significantly (p<0.05) lower in the outdoor PM, compared with indoor PM, and the significantly (p<0.05) higher $IC_{50}$ values were observed in the cancer cell lines (A-549 lung adenocarcinoma and AGS stomach adenocarcinoma), than those of normal MRC-5 fibroblasts and dental papilla tissue derived-mesenchymal stem cells (DSC). After being exposed to $100{\mu}g/ml$ outdoor PM for 7 days, the population doubling time (PDT) was significantly (p<0.05) increased in especially MRC-5 and DSC cell lines, compared with untreated cell lines. Further, the expression of senescence-associated ${\beta}$-galactosidase activity was up-regulated in all the cells exposed to outdoor PM than those of untreated control. Besides, the expression level of inflammation-associated genes, such as cyclooxygenase-2 (COX-2) and interleukin-6 (IL-6) was found to be significantly (p<0.05) increased in the outdoor PM-treated cell lines than those of untreated cell lines. Our results showed that PM induces the cytotoxicity via arrest of cell growth, cell damage and inflammation response.

• Journal of Gastric Cancer
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• v.6 no.3
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• pp.146-153
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• 2006

Purpose: Gastrointestinal stromal tumorsm (GISTs) are the most common mesenchymal tumors that arise anywhere in the tubular GI tract. The prognosis for GSTIs is important because f GISTs may metastasiwx in the liver or the abdominal cavity in an early stage. For the reason we examined the tumor size, the mitotic number, ki 67, p53, and c-kit mutation as independent prognostic factor for GISTs. Materials and Methods: A retrospective study was conducted in 76 patients who had been re-evaluated for confirmation of diagnosis between Jan 1998 and Dec. 2001. at Catholic University of medicine. Results: There were significant difference between the turner size, mitotic indices, ki 67, c-kit mutations and the 5-years survival rates. Tumor size (${\geq}5\;cm$) and mitotic index (${\geq}5/50\;HPF$) were statistically related to a significantly poor prognosis (P=0.017 and P=0.042, respectively). c-kit mutations in exon 11 were found in 7 cases c-kit mutation was observed more frequently in high risk patients, and there was a significant difference between c-kit mutation and survival (P=0.037). Elevated ki 67 was noted in 34 out of the 76 cases. High risk patients showed elevated ki67 index more frequently and there was significant relation with the survival rate (P=0.0417). Conclusion: We think that tumor size, mitotic index, Ki 67 and c-kit mutation are as independent prognostic factors for GISTs, but more research is needed.