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Background: Bone morphogenic proteins (BMPs) are important bone-induction factors, and the development of a suitable carrier for BMPs is a critical step to achieve osteoinductive function. The aims of the present study were to evaluate, at the cellular and molecular levels, the feasibility of recombinant human BMP-2 (rhBMP-2)--collagen composite scaffold and its efficiency for carrying BMP-2 in ectopic bone formation in rats. Methods: Scaffolds with (test) or without rhBMP-2 (control) were made and implanted into the calf muscle of 16 5-week-old rats. The tissue responses to the scaffolds were examined by histology. Masson's trichrome and von Kossa stainings were performed to examine collagen matrix deposition and calcification at 3, 7, 10, and 14 days. Expressions of bone phenotypic markers, alkaline phosphatase, osteocalcin, osteopontin, and bone sialoprotein were detected by reverse transcription polymerase chain reaction and immunohistochemistry. Results: No detectable adverse responses were noted around the implanted scaffolds, and the area of the resorbed scaffold had been replaced by young connective tissue by 3 to 7 days in both groups. In the rhBMP 2 composite scaffold, collagen matrix deposition was found in the implanted site on day 7 and initial signs of endochondral differentiation also appeared. Mineralization and the expressions of key bone proteins were demonstrated in chondroblasts and osteoblasts at 7 to 14 days. Molecular cascades of bone induction were not shown in control specimens. Conclusion: The rhBMP 2-atelocollagen scaffold showed excellent biocompatibility and possessed a bone inducing capacity in rat within 2 weeks, and, thus, may provide a potential application in tissue engineering of bone tissue. J Periodontol 2007; 78:335-343. [ABSTRACT FROM AUTHOR]

Five cases of oral malignant fibrous histiocytoma (MFH) in patients who had previously received radiotherapy in the head or neck region were included in this study. There were 3 men and 2 women. Four patients had been irradiated for nasopharyngeal carcinoma (NPC) and the other for a squamous cell carcinoma (SCC) involving the tongue and mouth floor. The MFH developed 2.5-11 years after the initial radiotherapy. Two cases of MFH occurred in the maxilla, two in the mandible, and the remaining one in the tongue, floor of mouth and mandible. Clinically, the oral post-radiation MFH presented as tender, reddish, elastic, lobulated masses with surface ulceration. Radiographic examination of the involved jaws revealed a poorly defined radiolucent lesion without any periosteal or endosteal reaction. The prognosis of these tumors was very poor. Although aggressive multimodality treatment had been applied, 3 of 5 patients eventually died of the disease, with a mean survival time of 17 months after establishing the diagnosis of MFH. In order to ensure the early diagnosis and treatment of this radiation-induced second malignancy, close oral follow-up is mandatory for patients who have received radiotherapy for head and neck malignancies. [ABSTRACT FROM AUTHOR]