The value of bone scintigraphy on the determination of the full extent of tumor involvement in jaw bones

Objective： To prospectively investigate the value of bone scintigraphy on determining the full extent of tumor involvement in jaw bones and to assess the presence of metastases. Methods： This study had local ethical committee approval, and all patients gave written informed consent. Thirty seven consecutive patients with primary malignant tumor in jaw bones were recruited for the study. Bone scintigraphy was performed in all patients before surgery to measure the full extent of bony involvement, which was compared with histologic findings. Results： Whole body scan revealed one case with multiple bony metastases. Resection specimens of 36 bone neoplasms were pathologically analyzed to identify type and size of each tumor. The lengths of the tumor involvement in jaw bones defined by bone scintigraphy and pathology were 5.62 ± 1.58 cm, 4.48 ± 1.57 cm, respectively （P 〈 0.05）. The tumor negative margins from removed specimens according to bone scintigraphy were pathologically confirmed. With histologic findings as the standard of reference, the accuracy of bone scintigraphy was 100% （36 of 36 patients） in determining the full extent of tumor involvement in jaw bones. Conclusion： Bone scintigraphy tends to offer specific guidelines in determining the appropriate extent of bone resection while entirely clearing the tumor cells and preserving functions whenever possible and in establishing the bony metastases.

Construction of Adeno-associated Virus System for Human Bone Morphogenetic Protein 7 Gene

To construct the recombinant adeno-associated virus （rAAV） vector with human bone morphogenetic protein 7 （BMP7） and observe the BMP7 mRNA expression in vitro, BMP7 CDS sequence was cloned into expression plasmid pAAV-MCS of AAV Helper Free System. The recombinant plasmid was identified with enzyme digestion and sequencing. The recombinant plasmid, pAAV-RC, pHelper were co-transfected into AAV-293 cells according to the calcium phosphate-based protocol. The viral stock was collected by 4 rounds of freeze/thaw. After purified and concentrated, the recombinant virus titer was determined by dot-blot assay. HEK293 cells were transfected with the recombinant virus at different MOI, and the expression of BMP7 mRNA was detected by RT-PCR. The results showed rAAV-BMP7 was constructed and packaged successfully. The physical particle titer was 2.5×10^11 vector genomes/mL. There was different expression level of BMP7 mRNA after transfecton. These data suggested that recombinant AAV mediated a stable expression of hBMP7 mRNA in 293 cells. The AAV production method may pave the way of an effective strategy for the jaw bone defection around dental implants.