• Journal of Periodontal and Implant Science
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• v.38 no.sup2
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• pp.355-362
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• 2008

Purpose: The carrier for the delivery of bone morphogenetic proteins(BMPs) should also serve as a scaffold for new bone growth. In addition, predictable bone formation in terms of the volume and shape should be guaranteed. This study evaluated the ectopic bone formation of recombinant human BMP-2(rhBMP-2) using a micro macroporous biphasic calcium phosphate (MBCP: mixture of ${\beta}TCP$ and HA) block as a carrier in a rat subcutaneous assay model. Materials and Methods: Subcutaneous pockets were created on the back of 40 male Sprague-Dawley rats. In the pockets, rhBMP-2/MBCP and MBCP alone were implanted. The blocks were evaluated by histological and histometric parameters after a healing interval of 2 weeks (each 10 rats; MBCP and rhBMP-2/MBCP) or 8 weeks (each 10 rats; MBCP and rhBMP-2/MBCP). Results: The shape and volume of the block was maintained stable over the healing period. No histological bone forming activity was observed in the MBCP alone sites after 2 weeks and there was minimal new bone formation at 8 weeks. In the rhBMP-2/MBCP sites, new bone formation was evident in the macropores of the block. The new bone area at 8 weeks was greater than at 2 weeks. There was a further increase in the quantity of new bone with the more advanced stage of remodeling. Conclusions: A MBCP block could serve as a carrier system for predictable bone tissue engineering using rhBMPs.

• Journal of Trauma and Injury
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• v.31 no.3
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• pp.177-180
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• 2018

Heterotopic bone formation in abdominal incisions is a recognized but uncommon sequela of abdominal surgery. On the other hand, the formation of ectopic bone is a well-recognized complication following arthroplasty of the hip. Heterotopic ossification of midline abdominal incision scars is a subtype of myositis ossificans traumatica. Ectopic bone formation of midline abdominal incisions may cause regional pain or discomfort in the patient after surgery. If symptomatic, treatment is complete excision with primary closure. Radiologically, it is important to distinguish this benign entity from postoperative complications. We report a 69-year-old male who underwent exploratory laparotomy for traumatic small bowel perforation. A segment of abnormal hard tissue was found in the abdominal wall. Heterotopic ossification may occur at various sites and is a recognized but infrequent sequela of exploratory laparotomy. This case highlights clinical and etiological features of this finding.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.2
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• pp.139-147
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• 1998

This study has been performed to evaluate the relationship between the remained mineral components in a decalcified bone matrix and an ectopic bone formation efficiency. The freezed rat diaphyseal cortical bones measuring 0.5cm in length were demineralized in heated 0.6N HCl at $60^{\circ}C$ for 5, 10, 15, 20, 25, 30, 35, 40 minutes, respectively, using a controlled heat ultrasonic cleaner. Each 1cc of decalcifying solution taken during decalcification procedure was used to calculate calcium content using calcium dignostics kit under 600nm of spectrophotomer. After decalcification, each specimen was also weighed. Then each prepared specimen was implanted into the dorsal pouch of 24 Sprague-Dawley rats divided into 8 groups by time course. The implants were harvested at 1, 2, and 3 weeks and prepared for routine H-E stain specimens to evaluate osteogenic activity. The results are as follows: 1. There was statistical significant difference in change of calcium concentration up to demineralization of 30 minutes and each allogenic bones decalcifed up to 20 minutes revealed 99.65% of decalcification in average. 2. There was statistical significant difference in change of weight in demineralized allogenic bone up to 20 minutes treatment but, no significant change was noted after that time. 3. The histologic analysis revealed active ectopic bone formation in the implanted allografts demineralized for 20, 25, 30 minutes, respectively. However, the other groups of allografts showed relatively poor osteoinductive activity. These findings suggest that complete decalcification with a minimized degeneration of collagen matrix is necessary to induce maximal osteogenesis by decalcified bone allograft.

• Journal of Yeungnam Medical Science
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• v.20 no.2
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• pp.142-151
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• 2003

To induce bone formation at ectopic site by tissue engineering and gene therapy, we transplanted collagen sponges containing rhBMP-7 transduced HEK 293 cells in the hypodermis of nude mice. Bone formation was investigated by histological and electron microscopic method at 3, 6, and 9 weeks after transplantation. At 9 weeks after transplantation, eosinophilic bony tissue was observed in the implanted collagen sponge and was confirmed as bone tissue by Von Kossa stain. In the transmission electron microscopic observation, the cells in newly formed bone tissue had eccentrically located nucleus and well developed rough endoplasmic reticulum (rER). Therefore, the cells were evaluated as osteoblasts. Those results suggest that it is possible to form a bone tissue in the ectopic site by transplantation of rhBMP-7 transduced HEK 293 cells. This will be contributed to push more advanced gene therapy for bone formation. However, the HEK 293 cell is unable to apply to the clinical gene therapy. Therefore it is worth to find more compatible cells for clinical application. In addition, collagen sponge is considered as an excellent scaffold and/or carrier for gene therapy and a good biomaterial for tissue engineering.

• 대한치주과학회:학술대회논문집
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• 2004.11a
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• pp.53-53
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• 2004

• Journal of Periodontal and Implant Science
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• v.53 no.1
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• pp.54-68
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• 2023

Purpose: The purpose of this study was to determine whether metformin (MF) could alleviate the expresssion of reactive oxygen species (ROS) and improve the osteogenic ability of bone marrow mesenchymal stem cells derived from diabetic rats (drBMSCs) in vitro, and to evaluate the effect of MF on the ectopic osteogenesis of drBMSCs in a nude mouse model in vivo. Methods: BMSCs were extracted from normal and diabetic rats. In vitro, a cell viability assay (Cell Counting Kit-8), tests of alkaline phosphatase (ALP) activity, and western blot analysis were first used to determine the cell proliferation and osteogenic differentiation of drBMSCs that were subjected to treatment with different concentrations of MF (0, 50, 100, 200, 500 µM). The cells were then divided into 5 groups: (1) normal rat BMSCs (the BMSCs derived from normal rats group), (2) the drBMSCs group, (3) the drBMSCs + Mito-TEMPO (10 µM, ROS scavenger) group, (4) the drBMSCs + MF (200 µM) group, and (5) the drBMSCs + MF (200 µM) + H₂O₂ (50 µM, ROS activator) group. Intracellular ROS detection, a senescence-associated β-galactosidase assay, ALP staining, alizarin red staining, western blotting, and immunofluorescence assays were performed to determine the effects of MF on oxidative stress and osteogenic differentiation in drBMSCs. In vivo, the effect of MF on the ectopic osteogenesis of drBMSCs was evaluated in a nude mouse model. Results: MF effectively reduced ROS levels in drBMSCs. The cell proliferation, ALP activity, mineral deposition, and osteogenic-related protein expression of drBMSCs were demonstrably higher in the MF-treated group than in the non-MF-treated group. H₂O₂ inhibited the effects of MF. In addition, ectopic osteogenesis was significantly increased in drBMSCs treated with MF. Conclusions: MF promoted the proliferation and osteogenic differentiation of drBMSCs by inhibiting the oxidative stress induced by diabetes and enhenced the ectopic bone formation of drBMSCs in nude mice.

• Journal of Periodontal and Implant Science
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• v.42 no.4
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• pp.136-143
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• 2012

Purpose: The osseointegration around titanium mini-implants installed in macroporous biphasic calcium phosphate (MBCP) blocks was evaluated after incubation with recombinant human bone morphogenetic protein-2 (rhBMP-2) in an ectopic subcutaneous rat model. Methods: Mini-implants (${\varphi}1.8{\times}12$ mm) were installed in MBCP blocks (bMBCPs, $4{\times}5{\times}15$ mm) loaded with rhBMP-2 at 0.1 mg/mL, and then implanted for 8 weeks into subcutaneous pockets of male Sprague-Dawley rats (n=10). A histomorphometric analysis was performed, and the bone-to-implant contact (BIC) and bone density were evaluated. Results: Significant osteoinductive activity was induced in the rhBMP-2/bMBCP group. The percentage of BIC was $41.23{\pm}4.13%$ (mean${\pm}$standard deviation), while bone density was $33.47{\pm}5.73%$. In contrast, no bone formation was observed in the bMBCP only group. Conclusions: This model represents a more standardized tool for analyzing osseointegration and bone healing along the implant surface and in bMBCPs that excludes various healing factors derived from selected animals and defect models.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.68-79
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• 1996

To investigate the efficiency of a fibrous collagen membrane(FCM) composed of bovine skin type I atelocollagen as a carrier for BMP, partially purified bovine BMP/FCM($0.3mg/10{\times}5{\times}1mm$) composites were implanted into the dorsal subcutaneous tissue of rats. FCM alone was also implanted as a control. The implants were harvested at 1, 2, 3, and 10 weeks after implantation, then prepared for routine light microscopic observation. The FCM alone did not induce osteogenesis and revealed no specific foreign body reaction nor was there any definite resorptive evidence for 10 weeks after implantation, while the BMP/FCM composites induced favorable bone formation in a process that resembled an endochondral and direct ossification mode. At 10 weeks, the well formed bone confined to embedded collagen fibers revealed hematopoietic marrow between bony trabeculae without evidence of resorptive or degenerative changes . These findings support the suggestion that BMP may induce undifferentiated mesenchymal cells into either chondroblasts or osteoblasts or both independantly according to the chemico- physical characteristics of the carrier, which develops the endochondral and/or direct bone formation process, and suggest that the FCM may be a favorable carrier for BMP.

• Journal of Periodontal and Implant Science
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• v.39 no.2
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• pp.119-128
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• 2009

Purpose: The aim of this study was to evaluate the stemness of cells from canine dental tissues and bone marrow. Methods: Canine periodontal ligament stem cells (PDLSC), alveolar bone stem cells (ABSC) and bone marrow stem cells(BMSC) were isolated and cultured. Cell differentiations (osteogenic, adipogenic and chondrogenic) and surface antigens (CD146, STRO-1, CD44, CD90, CD45, CD34) were evaluated in vitro. The cells were transplanted into the subcutaneous space of nude mice to assess capacity for ectopic bone formation at 8 weeks after implantation. Results: PDLSC, ABSC and BMSC differentiated into osteoblasts, adipocytes and chondrocytes under defined condition. The cells expressed the mesenchymal stem cell markers differently. When transplanted into athymic nude mice, these three kinds of cells with hydroxyapatite /${\beta}$- tricalcium phosphate (HA/TCP) carrier showed ectopic bone formation. Conclusions: This study demonstrated that canine dental stem cells have stemness like bone marrow stem cells. Transplantation of these cells might be used as a therapeutic approach for dental stem cell-mediated periodontal tissue regeneration.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.859-869
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• 2007

Naked DNA and standard vectors have been previously used for gene delivery. Among these, PEI can efficiently condense DNA and has high intrinsic endosomal activities. The aim of this study is to investigate whether the cationic polycation PEI could increase the transfection efficiency of BMP expressing DNA using a vector-loaded collagen sponge model. BMP-2/pcDNA3.1 plasmid was constructed by subcloning human BMP-2 cDNA into the pcDNA3.1 plasmid vector. PEI/DNA complexes were prepared by mixing PEI and BMP-2/pcDNA3.1 and the constructed complexes were loaded into the collagen sponges. In vitro studies, BMSCs were transfected with the PEI/BMP-2/pcDNA3.1 complexes from collgen sponge. The level of secreted BMP-2 and alkaline phosphatase activities of transfected BMSCs were significantly higher in PEI/BMP-2/pcDNA3.1 group than in BMP-2/pcDNA3.1 group (p<0.05). Transfected BMSCs were cultured and mineralization was observed only in cells treated with PEI/BMP-2/pcDNA3.1 complexes. In vivo studies, PEI/BMP-2/pcDNA3.1/collagen, BMP-2/pcDNA3.1/collagen and blank collagen were grafted in skeletal muscle of nude mice. Ectopic bone formation was shown in PEI/BMP-2/pcDNA3.1/collagen grafted mouse 4 weeks postimplantation, while not in BMP-2/pcDNA3.1 grafted tissue. This study suggests that PEI-condensed DNA encoding for BMP-2 is capable of inducing bone formation in ectopic site and might increase the transfection rate of BMP-2/pcDNA3.1. As a non-viral vector, PEI offers the potential in gene therapy for bone engineering.