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Objective To study the effects of PDLLA/HA/DBMV biomaterials on cell proliferation by comparison of polyactic acid (PDLLA) and decalcified bone matrix (DBM) so as to evaluate the biocompatibility of the biomaterials at the cell level. Methods The isolated third generation human fetal osteoblasts (suspension, 3.5?10 5/ml) were inoculated onto the biomaterials of PDLLAHA/DBM, PDLLA, and DBM for 1, 2, 3, 5, and 7 d. Proliferation rates of cells on different materials were determined by flow cytometry. Results The osteoblast proliferation rate on PDLLA/HA/DBM was higher than that on PLA and DBM. Conclusion PDLLA/HA/DBM is compatible for the growth of osteoblasts.
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Objective To evaluate the osteocompatibility of poly(D,L lactic acid)/ hydroxyapatite/decalcified bone matrix (PDLLA/HA/DBM) and to compare the osteocompatibility with that of PDLLA and DBM. Methods The isolated human osteoblasts from the femoral head of patients were inoculated onto PDLLA/HA/DBM, PLA, and DBM. The interface between biomaterial and osteoblasts was investigated with phase contrast microscope and scanning electron microscope. Results Osteoblasts were attached tightly to the surface of biomaterial with an arched structure and had normal morphology. The extracellular collagenous matrix covered the surface of biomaterial and packed the granules of biomaterial completely. Conclusion PDLLA/HA/DBM can form osteointegrated interface at the early stage with good biocompability.
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Objective To investigate the activity and mRNA expression of DNA methyltransferase(DNMT) in gliomas and the effects of chemotherapy and radiotherapy on them. Methods A total of 30 cases of glioma were divided in four groups: operation group, treatment groups A(operation+chemotherapy), B(operation+radiotherapy) and C(operation+radiotherapy +chemotherapy). Group A was treated with VM 26 and Semustine MeCCNU, B with continuous external radiation with X ray accelerated by 10MV accelerator. Fresh tissues removed surgically were used for the detection of the DNMT activity of tumors by 3H labeled tracing microassay and DNMT mRNA expression by RT PCR. Results The 2 year survival rate of the patients treated by chemotherapy or /and radiotherapy increased significantly, but the activity and the mRNA expression of DNMT decreased significantly. Conclusion DNMT is involved in the genesis and development of gliomas. The curative effect of chemotherapy and radiotherapy may be related with DNMT activity and expression. Detection of DNMT activity and DNMT mRNA may play an important role in the prognosis of gliomas and choice of treatment regimens.