• Journal of Veterinary Clinics
• /
• v.18 no.2
• /
• pp.156-159
• /
• 2001

A 6-year-old male mongrel dog with a 7-month history of ulnar-radial nonunion fracture was treated with implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2). The dog had received surgical correction three times prior to the admission but radiography of the affected limb revealed a typical figure of nonunion fracture. Glossly, the fractured ends were sclerotic and the area between the ends was filled with fibrous tissue. After debridement the shaft was fixed by an 10-hole plate. rhBMP-2 at a total dose of 256 micrograms was implanted with a synthetic carrier into the 10-mm defect formed by the debridement. Callus formation responding to rhBMP-2 was radiographically observed at 4 weeks after implantation and the defect bridged both fracture ends by 8 weeks after implantation. The plate was removed at 12 months after implantation. Any complications were not observed for 5 months after removal of the plate.

• Journal of Periodontal and Implant Science
• /
• v.30 no.2
• /
• pp.389-405
• /
• 2000

The purpose of this study is to evaluate the effect of IGF-I for DNA synthetic activity and the mRNA expression of bone matrix protein, type I collagen and osteopontin in prolifetation and differentiation of MC3T3-E1 cells. To evaluate DNA synthetic activity, cells were seeded at $2{\times}10^4cells/ml$ in 24 well plates and to evaluate mRNA of type I collagen and osteopontin cells were seeded at $5{\times}10^5cells/ml$ in 100mm culture dishes. These cells were cultured in alpha-minimum essential medium(${\alpha}-MEM$) containing 10% fetal bovine serum at $37^{\circ}C$, 5% $CO_2$ incubator. For DNA synthetic activity test 1, 10, 100ng/ml IGF-I were added to the cells which had been cultured for 3 days before 24 hours. For type I collagen mRNA expression 1, 10ng/ml IGF-I were added to the cells which had been cultured for 5, 10 days and for osteopontin mRNA expression 0.1, 1, 10ng/ml IGF-I were added to the cells which had been cultured for 5, 15, 20 days. Cell proliferaton was measured by the incorporation of [$^3H$]-thymidine into DNA and expression for type I collagen and osteopontin were measured by northern blot analysis. The results were as follows : DNA synthetic activity were generally higher in experimental group than control group. Expressions of type I collagen mRNA were higher at 5 day group and much lower at 10 day group in the control groups. In the experimental groups, mRNA expressions were slightly increased when 1 ng/ml IGF-I were added to 5 day group and decreased in all experimental 10 day groups. Expressions of osteopontin mRNA were higher at 20 day groups and lower at 15 day groups than the control groups. In the experimental groups, mRNA expressions were incereased when 0.1, 1 ng/ml IGF-I were added to 5 day group and in all the 15 day groups, but decreased when 0.1, 1, 10 ng/ml IGF-I were added to 20 day groups. IGF-I stimulated DNA synthetic activity of MC3T3-E1 cells during proliferation stage significantly, did not greatly changed effects on type I collagen mRNA expression and stimulated osteopontin mRNA expression at 15 day especially. In conclusion, we suggests that IGF-I have a tendency of stimulation effect of DNA synthetic activity but do not stimulate type I collagen mRNA in proliferation stage of MC3T3-E1 cell cultures, and stimulate osteopontin mRNA in differentiation stage of MC3T3-E1 cell cultures.

• Journal of Periodontal and Implant Science
• /
• v.27 no.3
• /
• pp.633-645
• /
• 1997

The recent trend of research and development on guided tissue regeneration focuses on the biodegradable membranes, which eliminate the need for subsequent surgical removal. They have demonstrated significant and equivalent clinical improvements to the ePTFE membranes. This study evaluate guided tissue regeneration wound healing in surgically induced intrabony periodontal defects following surgical treatment with a synthetic biodegradable membranes, made from a copolymer of glycolide and lactide, in 8 beagle dogs. After full thickeness flap reflection, exposed buccal bone of maxillary and mandibular canine and premolar was removed surgically mesiodistally and occlusoapically at $6mm{\times}6mm$ in size for preparation of periodontal defects. In experimental sites a customized barrier was formed and fitted to cover the defect. Flap was replaced slightly coronal to CEJ and sutured. Plaque control program was initiated and maintained until completion of the study. In 4, 8, 16 and 24 weeks after surgery, the animals were sacrificed and then undecalcified specimens were prepared for histologic evaluation. Histologic examination indicated significant periodontal regeneration characterized by new connective tissue attachment, cementum formation and bone formation. These membranes showed good biocompatibility throughout experiodontal period. The barriers had been completely resorbed with no apparent adverse effect on periodontal wound healing at 24 weeks. These results implicated that present synthetic biodegradable membrane facilitated guided tissue regeneration in periodontal defect.

• Journal of Veterinary Clinics
• /
• v.39 no.6
• /
• pp.302-310
• /
• 2022

Recently, in human medicine and veterinary medicine, interest in synthetic bone graft is increasing. Among them, bone morphogenic protein (BMP) is currently being actively researched and applied to clinical trials. However, BMP has the disadvantage of being expensive and easily absorbed into surrounding tissues. Therefore, BMP requires the use of small amounts and rhBMP (recombinant human bone morphogenetic protein)-2 carriers that can be released slowly. Hydrogel has the property of swelling a large amount of water inside when it is aqueous solution, and when it is, it consists of more than 90 percent water. Using these properties, hydrogels are often used as rhBMP-2 carrier. The scaffold used in this study is a hydrogel made from which keratin is extracted using human hair and based on it. In this study, we wanted to see the effect of bone formation in the calvarial defect model by using keratin-based hydrogel made with human hair as a scaffold. The experiment was conducted by dividing 3 groups a total of 12 mice. Calvarial bone defect is set to all 4 mm diameters. Bone formation was evaluated by using gross evaluation, micro-computed tomography (micro-CT), immunohistochemistry. Groups using keratin-based hydrogel were significantly observed compared to Group 1s, and the most bone formations were found when rhBMP-2 and hydrogel were used. This represents the superiority of the functions of the rhBMP-2 carrier by a new material, keratin-based hydrogel. Through gross evaluation, micro-CT, and immunohistochemistry, we can confirm that keratin-based hydrogel is a useful rhBMP-2 carrier.

• Macromolecular Research
• /
• v.9 no.5
• /
• pp.267-276
• /
• 2001

In order to endow with new bioactive functionality from demineralized bone particle (DBP) as natural source to poly(L-lactide) (PLA) synthetic biodegradable polymer, porous DBP/PLA as natural/synthetic composite scaffolds were prepared and compared by means of the emulsion freeze drying and solvent casting/salt leaching methods for the possibility of the application of tissue engineered bone and cartilage. For the emulsion freeze drying method, it was observed that the pore size decreased in the order of 79$\mu\textrm{m}$ (PLA control) > 47$\mu\textrm{m}$ (20% of DBP) > 23 $\mu\textrm{m}$ (40% of DBP) > 15$\mu\textrm{m}$ (80% of DBP). Porosities as well as specific pore areas decreased with increasing the amount of DBR. It can be explained that DBP acts like emulsifier resulting in stabilizing water droplet in emulsion. For the solvent casting/salt leaching method, a uniform distribution of well interconnected pores from the surface to core region were observed the pore size of 80 ∼70 $\mu\textrm{m}$ independent with DBP amount. Porosities as well as specific pore areas also were almost same. For pore size distribution by the mercury intrusion porosimeter analysis between the two methods, the pore size distribution of the emulsion freeze drying method was broader than that of the solvent casting/salt leaching method due to the mechanism of emulsion formation. Scaffolds of PLA alone, DBP/PLA of 40 and 80%, and DBP powder were implanted on the back of athymic nude mouse to observe the effect of DBP on the induction of cells proliferation by hematoxylin and eosin staining for 8 weeks. It was observed that the effect of DBP/PLA scaffolds on bone induction are stronger than PLA scaffolds, even though the bone induction effect of DBP/PLA scaffold might be lowered than only DBP powder, that is to say, in the order of DBP only > DBP/PLA scaffolds of 40 and 80% DBP > PLA scaffolds only for osteoinduction activity. In conclusion, it seems that DBP plays an important role for bone induction in DBP/PLA scaffolds for the application of tissue engineering area.

• Journal of Periodontal and Implant Science
• /
• v.28 no.1
• /
• pp.145-160
• /
• 1998

The ultimate goal of periodontal therapy is the regeneration of periodontal tissue which has been lost due to destructive periodontal disease, and numerous kinds of materials and techniques have been developed to achieve this goal. Bone grafts include autografts, allografts, xenografts and synthetic grafts. Among the synthetic grafts, bioactive glass has been used in dentistry for more than ten years and Fetner reported improved new bone formation and more amount of new attachment after grafting PerioGlas, a kind of bioactive glass, in 2-wall defects of monkeys in 1994. It Is well known that 1-wall defects have less osteogenic potential and more epithelial migration, so we need to study the erect of bioactive glass in 1-wall dejects in dogs. The present study evaluates the effect of bioactive glass on the epithelial migration, alveolar bone regeneration, cementum formation and gingival connective tissue attachment in intrabony detects of dogs. Four millimeter deep and four millimeter wide 1-wall defects were surgically cheated in the mesial aspects of premolars. The test group received bioactive glass with a flap procedure and the control underwent flap procedure only. Histologic analysis after 8 weeks of healing revealed the following results: 1. The height of gingival margin was 1.30{\pm}0.73mm$ above CEJ in the control and $1.40{\pm}0.78mm$ in the test group. There was no statistically significant difference between the two group. 2. The length of epithelial growth (the distance from CEJ to the apical end of JE) was $1.74{\pm}0.47mm$ in the control and $1.12{\pm}0.36mm$ in the test group. These was a statistically significant difference between the two groups (P<0.01). 3. The length of new cementum was $2.06{\pm}0.73mm$ in the control and $2.62{\pm}0.37mm$ in the test group. There was no statistically significant difference between the two groups. 4. The length of new bone was $1.83{\pm}0.74mm$ in the control and $2.39{\pm}0.59mm$ in the test group. There was no statistically significant difference between the two groups. These results suggest that the use of bioactive glass 1-wall intrabony defects has significant effect on the prevention of junctional epithelium migration, but doesn't have any significant effect on new bone and new cementum formation.

• Journal of Periodontal and Implant Science
• /
• v.37 no.4
• /
• pp.719-732
• /
• 2007

Purpose: Various bone graft materials are being used for periodontal tissue regeneration. Th materials are being developed continuously for ideal clinical effects. Therefore, it is necessary to identify the clinical characteristics of each bone graft material through comparing the various bone graft materials statistically and in doing so, proposing a more efficient bone graft material. In this study, the following results were attained through comparing the clinical effects among the bone graft materials, using the statistical method based on the clinical studies published at the department of periodontology of Yonsei hospital. Materials and Method: 6 selected studies of department of Periodontology at Yonsei University Hospital were based on clinical study of bone grafting in intrabony defects. It was compared the clinical parameters among the 6 clinical studies, using the statistical META analysis. Result: When comparing the probing depth reduction, there was a relatively great amount of decease when using the xenograft, Anorganic Bovine Derived Hydroxapatite Bone Matrix/Cell Binding Peptide(ABM/P-15: PepGen $P-15^{(R)}$) and the autogenous bone and absorbable membrane, d, 1-alctide/glycolide copolymer(GC: $Biomesh^{(R)}$). The allogfrafts showed a relatively low decrease in the probing depth and clinical attachment change. It also showed a slight decrease in the bone probing depth. The allografts showed various results according to different bone graft materials. When comparing the ABM/P-15 and bovine bone $powder(BBP^{(R)})$, ABM/P-15 showed a relatively high clinical attachment level and the bovine bone powder showed a relatively high clinical attachment level. The probing depth change and gingival recession change showed a lower value than the mean value between the two bone graft materials. The synthetic bone showed a relatively high decrease in clinical attachment level and periodontal probing depth change. There was a relatively larger amount of gingival recession when using Bioactive Glass(BG) but a relatively low bone regeneration effect was seen. Conclusion: Good restorative results of the periodontal tissue can be attained by applying the various bone graft materials being used today after identifying the accurate clinical effects.

• Clinics in Shoulder and Elbow
• /
• v.26 no.2
• /
• pp.191-204
• /
• 2023

Avascular necrosis (AVN) of the humeral head is a rare, yet detrimental complication. Left untreated, humeral head AVN frequently progresses to subchondral fracturing and articular collapse. Cases of late-stage humeral head AVN commonly require invasive procedures including humeral head resurfacing, hemiarthroplasty, and total shoulder arthroplasty (TSA) to improve clinical outcomes. However, in cases of early-stage AVN, core decompression of the humeral head is a viable and efficacious short-term treatment option for patients with pre-collapse AVN of the humeral head to improve clinical outcomes and prevent disease progression. Several techniques have been described, however, a percutaneous, arthroscopic-assisted technique may allow for accurate staging and concomitant treatment of intraarticular pathology during surgery, although further long-term clinical studies are necessary to assess its overall outcomes compared with standard techniques. Biologic adjunctive treatments, including synthetic bone grafting, autologous mesenchymal stem cell/bone marrow grafts, and bone allografts are viable options for reducing the progression of AVN to further collapse in the short term, although long-term follow-up with sufficient study power is lacking in current clinical studies. Further long-term outcome studies are required to determine the longevity of core decompression as a conservative measure for early-stage AVN of the humeral head.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2009.11a
• /
• pp.12.1-12.1
• /
• 2009

Nano-hydroxyapatite (N-HAp)has shown the pivotal role in producing bone-regenerative materials since it has similarity to natural bone minerals in terms of size, morphology, and the composition. Currently, the combination of biopolymers and N-HAp is recognizedas an attractive approach in generating hybrid scaffolds for bone tissueengineering. Surface engineering is an important issue since it determines whether cells can effectively adhere and proliferate on porous scaffolds. We aim to develop a synthetic approach to porous 3D scaffolds by immobilizing N-HAp on pore surfaces. The discrete nano-level anchoring of N-HAp on the scaffold pore surface is achieved using surface-repellent stable colloidal N-HAp with surface phosphate functionality. This rational surface engineering enables surface-anchored N-HAp to express its overall intrinsic bioactivity,since N-HAp is not phase-mixed with the polymers. The porous polymer scaffolds with surface-immobilized N-HAp provide more favorable environments thanconventional bulk phase-mixed polymer/N-HAp scaffolds in terms of cellular interaction and growth. In vitro biological evaluation using alkalinephosphatase activity assay supports that immobilized N-HAp on pore surfaces of polymer scaffolds contributed to the more enhanced in vitro osteogenicpotential. Besides, the scaffolds with surface-exposed N-HAp provide favorable environments for enhanced in vivo bone tissue growth, estimated by characteristic biomarkers of bone formation such as collagen. The results suggest that newly developed hybrid scaffolds with surface-immobilized N-HApmay serve as a useful 3D substrate with pore surfaces featuring excellent bonetissue-regenerative properties. Acknowledgement. This research was supported by a grant (code #: 2009K000430) from 'Center for Nanostructured Materials Technology' under '21st Century Frontier R&D Programs' of the Ministry of Education, Science and Technology, Korea.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.36 no.4
• /
• pp.243-249
• /
• 2010

Tissue engineered bone (TEB) can replace an autogenous bone graft requiring an secondary operation site as well as avoid complications like inflammation or infection from xenogenic or synthetic bone graft. Adult mesenchymal stem cells (MSC) for TEB are considered to have various ranges of differentiation capacity or multipotency by the donor site and age. This study examined the effect of age on proliferation capacity, differentiation capacity and bone morphogenetic protein-2 (BMP-2) responsiveness of human bone marrow stromal cells (hBMSC) according to the age. In addition, to evaluate the effect on enhancement for osteoblast differentiation, the hBMSC were treated with Trichostatin A (TSA) and 5-Azacitidine (5-AZC) which was HDAC inhibitors and methyltransferase inhibitors respectively affecting chromatin remodeling temporarily and reversibly. The young and old group of hBMSC obtained from the iliac crest from total 9 healthy patients, showed similar proliferation capacity. Cell surface markers such as CD34, CD45, CD90 and CD105 showed uniform expression regardless of age. However, the young group showed more prominent transdifferentiation capacity with adipogenic differentiation. The osteoblast differentiation capacity or BMP responsiveness was low and similar between young and old group. TSA and 5-AZC showed potential for enhancing the BMP effect on osteoblast differentiation by increasing the expression level of osteogenic master gene, such as DLX5, ALP. More study will be needed to determine the positive effect of the reversible function of HDAC inhibitors or methyltransferase inhibitors on enhancing the low osteoblast differentiation capacity of hBMSC.