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.

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.

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.

Objective To investigate the peri-nasopharyngeal invasion patterns of nasopharyngeal carcinoma (NPC) on MRI and its relationship with tumor staging. Methods One thousand five hundred and seventy-three patients with newly diagnosed NPC which were histo-pathologically proved were retrospectively studied. The MRI manifestations and invasion patterns of the NPCs were elevated according to the 2008 Tstaging system of NPC. Z test was used to analyze the rate of adjacent structures invasion in NPCs. Results The structures invaded by NPCs included pharyngobasilar fascia in 1299 cases (82. 58% ); parapharyngeal space, 1090 ( 69. 29% ); nasal cavities, 304 ( 19. 33% ); oropharynx, 49 ( 3. 12% ); carotid space,514(32. 68% ); medial pterygoid muscle, 661 (42. 02% ); lateral pterygoid muscle, 210( 13. 35% ); skull base bones, 943(59. 95% ); cranial nerves, 630(40. 05% ) and paranasal sinuses, 242 ( 15.38% ). The T-stage distribution was T1, 242 cases ( 15.38% ); T2, 288 ( 18. 31% ); T3, 410 (26. 06% ) and T4,633 (40. 24% ). Among the cases with nasal cavities invasion, 90. 46% (275/304)showed the involvement of the structures seen in T3 or T4 stage, which was found in all cases with oropharynx invasion. In addition,69. 14% (457/661) of cases with medial pterygoid muscle invasion and 92. 15% (223/242) of cases with paranasal sinuses invasion showed the involvement of structures seen in T4 stage. As for the invasion patterns of NPC, the lateral invasion of pharyngobasilar fascia was more frequent than upward invasion of skull base (Z = 14. 025, P ＜ 0. 01 ) and downward invasion of oropharynx ( Z = 45.032, P ＜ 0. 01 ), and the downward invasion of oropharynx was less frequent than upward invasion of skull base ( Z = 34. 301, P ＜ 0. 01 ) and forward invasion of nasal cavities ( Z = 14. 404, P ＜ 0. 01 ). Conclusion NPC has a predilection of lateral invasion rather than upward and downward invasion, and its upward and forward invasion are more common than downward invasion.

Objective To understand with greater clearness the genetic polymorphism of (GCT)n repeat of MHC class I chain-related gene A (MICA)in some Chinese populations and provide preliminary genetic evidence for the independent origin of Chinese Baima Tibetan (BMT). Methods ACD-blood or saliva specimens of 411 unrelated individuals from four Chinese populations were collected. A primer pair spanning exon 5 of MICA gene was used to amplify the GCT region. Alleles were detected by PCR and denaturing PAGE. Comparison of the allelic distributions among the four populations was carried out. Results Five previously reported alleles have been observed in all the four populations, but the allelic distributions are different from one another. The most frequent allele is the A5 in all the four populations (0.325 in BMT, 0.345 in Tibetans, 0.390 in Chengdu Hans and 0.319 in Qiangs). A5.1 allele is the second most frequent allele in Chengdu Hans (0.230) and in Qiangs (0.293), while the second most frequent alleles for BMT and Tibetans are A4 (0.254) and A9 (0.272) respectively. The distribution of alleles in BMT is significantly different from that in the other three populations. Conclusion Alleles of MICA gene exon 5 are conservative in all populations studied so far. The results suggest that genetically BMT might be an independent ethnic population.