A novel approach of vaccination against cancer is to exploit dendritic cells (DC) as the best antigen presenting cells (APC) and actively immunize cancer patients with a sample of autologous or allogeneic DC primed with tumor antigens. DC vaccination is still at its early stage, however, valuable proofs of concept have been obtained with respect to the capacity of DC to expand cancer directed immune responses. The methods for preparing DC are being improved continuously, and there are many opportunities to improve efficacy at the level of DC biology. An increased number of clinical studies will drive the development of this new area. This paper reviews the production of dendritic cell tumor vaccines and their use in clinical trials, as well as emphasizes some unresolved questions in this immunotherapy.

Objective To analyze the ultra microstructure and histological properties of implanted composites of decalcified bone matrix (DBM) impregnated calcium phosphate cement (CPC) with recombinant human bone morphogenetic protein-2 (rhBMP-2) in bone defect, and evaluate the osteoplastic efficiency of this composites. Methods The rabbit DBM was prepared beforehand. The composites of DBM impregnated CPC with rhBMP-2 was made at 0.2 proportion of DBM. The rabbit's bone defect of femur condyle was filled with implantation of the composites (group A, n=12) or CPC (group B, n=12) or bone cement (group C, n=12). Animals were sacrificed at 6, 12, or 24 weeks after operation, and the implants were examined by histological technique and scanning electron microscopy (SEM). Results In group A, at the 6th week after operation, the interface region between implants and bone tissue became fuzziness, and was crossed by the generated fibers of bone tissue, and filled with woven bone growing inside into the composites; at the 12th week after operation, blood vessels, osteoblasts and new bone were generated inside of composites; at the 24th week after operation, the bone defects were recovered and became solid union, most of the implants were replaced by new bones. In group B, at the 6th week after operation, the interface of CPC and bone tissue was sharp, and was not crossed by new bones; at the 24th week after operation, the bone defects were still filled with materials of CPC and no new bone was found inside CPC. In group C, at the 24th week after operation, the interface of bone cement and bone remained non-union. Higher osteoblastic activity,more neogenetic blood vessels and higher growth rate of woven bone were observed in group A compared with those in group B. Conclusions For bone defect, the implantation of composites with DBM proportion of 0.2 can stimulate the growth of osteoblast, blood vessel and woven bone. It is biodegradable and can be replaced by autogenous bone.

Objective To investigate the characteristics, degradation and biocompatibility of a woven chitosan fiber (CF). Methods Scanning electron microscopic observation, deteronination of density, degree of swelling and tensile strength were performed to characterize the CF. In vitro degradation was observed by immersing CF in buffered aqueous solution of pH 6 containing lysozyme at 37 ℃, while in vivo degradation was studied after intramuscular implantation of CF in rats. Furthermore, rat mesenchymal stem cells were directly cultured on CF to estimate its toxicity. Results The diameter of CF was about 2000?63?m, with a sleek surface. The density and rate of swelling were 1.093?0.27g/cm3 and 2.30?0.21, respectively. The tensile strength was 80.18?1.56MPa. Specific viscosity, measured after the addition of lysozyme to the solution, decreased dramatically within 2 hours compared with that of the control mixture without enzyme. There was obvious inflammatory reaction after intramuscular implantation in the first week after surgery, bat inflammation subsided gradually. Biodegradation was not obvious within 4 weeks, but majority of it was absorbed in twelve weeks. Cells grew well on it with normal morphology, and no inhibition of cell proliferation could be observed. Conclusion Woven CF has a good tensile strength and fairly good biodegradation and biocompatibility, and it can be used in bone and cartilage tissue engineering.

[Objective]To analyze the clinical effect of microwave hyperthermia in limb salvage surgery for malignant bone tumor of extremities. [Methods]From July 1999 to July of 2005, 309 patients with malignant or bone tumors of extremities were treated by heat necrosis of tumor-bearing bone in situ for limb salvage.The most common diagnosis was osteosarcoma. The first step of the traditional limb salvage was en bloc resection of the tumor-bearing bone. For the novel method, the tumor bearing bone was just separated from surrounding normal tissues, and was devitalized by hyperthermia in situ.After re-strengthening the dead bone, its mechanical property became strong enough to support the body weight.[Results]The beyond 3 years survival rate was 60.2% for high-grade malignancy. In great majority of the patients, cosmetic and useful limbs were preserved. The complication rate was lower than that in the literature reports.[Conclusion]The long term experience has proved that the new method has made its way in the field of orthopedic oncology. The applying of hyperthermia for treatment of bone tumors is an effective, simple, and inexpensive method. The oncological and functional results are encouraging. Hyperthermia should deserve more attention than it has in the clinical practice.

[Objective] To analyze the treatment of malignant of highly aggressive bone tumors of pelvis by microwave-induced hyperthermia.[Methods]A novel surgical model was devised:after careful dissection of the tumor-bearing bone from surrounding normal tissues,the microwave antennae array was inserted into the tumor mass for emitting electromagnetic microwave which produced tumor cellular death via thermo-coagulation.No special reconstruction procedure was necessary,excepting the strengthening measures.[Results]From May 1994 to December 2005,152 patients with pelvic malignant or highly aggressive tumors received radical thermotherapy.Among 67 patients with stage IB tumors,48 patients achieved local and systematic control.Among 61 patients with stage IIB tumors,19 patients died from lesion,and the remaining 42 patents did not developed either metastasis or local recurrence after 3 to 11 years.Of 24 patients with pelvic metastatic lesions,11 patients collapsed during six months to three years,and 13 patients still lived without evidence of disease within one to seven years.In the majority of the patients,functional and cosmetic acceptable limbs were reserved.[Conclusion]The results revealed that the novel and greatly simplified method is justified from both oncological and functional standpoints.Hyperthermia should deserve more attention than it has in this field.

[Objective] To investigate the influence of Chitosan fiber combined with gelatin on the mechanical property of calcium phosphate cement.[Methods]Calcium phosphate cement composite by the incorporation of chitosan fiber and 5 wt% gelatin was investigated on flexural strength,phase composition,scanning electron microscopy observation and cytotoxicity assays.[Results]Fiber volume fraction had a significant effect on the flexural strength,and the post hoc test revealed that significant difference in the flexural strength was recognized(P

A composite material of decalcified bone matrix (DBM) and bone cement (BC) combined with bovine bone morphogenitic protein (bBMP) was used to repair canine femoral defect caused by microwave induced hyperthermia. The composite material was examined with scan electron microscope and its biomechanical properties were assessed. Then a canine femoral defect was produced by microwave induced hyperthermia, and the composite material was implanted.Then the femurs were examined with X ray, 99m Tc MDP bone scintigraphy, histology and biomechanics at different postoperative periods. It was found that DBM and BC were tightly connected in a multipolar mode with irregular gaps in a diameter of 400?m to 800?m. Callus was formed in the first month and its amount was most abundant in the third month as shown by X ray examination. The new bone was formed in the composite material,and it was confirmed by bone scintigraphy and histology. The border of new bone was connected with the normal bone. So the composite material could merge with the normal bone finally.

Objective To investigate the apoptosis induction effect of recombinant caspase-3 expression on osteosarcoma cell line SOSP-9901. Methods Recombinant caspase-3 gene was subcloned into the GFP reporter vector pEGFP-C1 to generate the expression vector pEGFP-caspase-3 by DNA recombinant technique. pEGFP-caspase-3 was transfected into human osteosarcoma cell line SOSP-9901 by Lipofectamine 2000. The expression of recombinant caspase-3 was determined by RT-PCR. The morphological changes of transfected cells were observed under flurescent and electronic microscope. The cell survival rate of transfected cells was assayed by MTT method. Results Recombinant caspase-3 gene could be stably expressed in the transfected SSOP-9901 cells. Recombinant caspase-3 could obviously induce SOSP-9901 apoptosis, and inhibit SSOP-9901 cell proliferation in vitro. Conclusion Recombinant caspase-3 could inhibit the growth of the osteosarcoma cell line SOSP-9901 and induce it into apoptosis.

Objective To investigate the specific antitumor effects induced by allogeneic dendritic cells (DCs)/osteosarcoma cell fusion vaccine in rats. Methods Fusion vaccine of DCs derived from Wistar rat bone marrow and osteosarcoma cells (UMR106) derived from SD rat was generated by electroporation method, and purified by immunomagnetic beads coated with monoclonal antibody OX62, then cocultured with T lymphocytes derived from SD bone marrow to stimulate the proliferation of the T lymphocytes. The proportion of CD8+ and 44+ cells was determined by flow cytometry, and the anti-tumor activity of cytotoxic T lymphocytes (CTLs) was determined by MTT assay. The SD rat osteosarcoma model was established and active immunotherapy was performed through intradermal injection, and the survival rate of the model rats was observed. Results After cocultured with allogeneic fusion vaccine, the proliferation of T cells increased significantly, and the proportion of CD8+ cells increased from 34.2% to 74.9%, while of CD4+ cells decreased from 59.2% to 19.1% (P

Objective:To explore caspase-6's effect on the apoptosis of osteosarcoma cell line SOSP 607. Methods: The expression level of caspase-6 in the osteosarcoma cell line SOSP-9067 was examined by RT-PCR method. The adeno-virus adv5 vector with caspase-6 gene was constructed and transferred into the osteosarcoma cell line SOSP-9607 by lipo-fection. The cell survival rate after transfection was assayed by MTT method. The cell morphological changes were observed by microscope and electron microscope, the apoptosis of transferred cells were examined by gel electrophoresis. Results:No expression of caspase-6 was examined in the osteosarcoma cell line SOSP-9607. A high expression of caspase-6 was identified by RT-PCR after the transfection. The cell growth curve declined after transferring caspase-6. Electrophoresis of DNA displayed the apoptosis ladder. Conclusion: Transferring caspase-6 into the osteosarcoma line SOSP-9607 may inhibit the growth of the osteosarcoma cell line SOSP-9607 and this effect might be achieved by inducing apoptosis.