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Objective: To evaluate the biocompatibility, degradation and bone formation activity of a new bone substitute for bone grafting, nacre/polylactic acid composite artificial bone (NPCB)., Methods: Radial bone defects 1.5 cm in length were induced in 32 New Zealand rabbits and immediately filled with NPCB or nothing. The animals' local and whole body responses to the implants were observed after the operation, and the serum calcium levels were detected 1 week and 4 weeks postoperatively. Tissue response, new bone formation in the defects and degradation of the implants were evaluated by X-ray, and examination of the bone mineral content (BMC) in the defects and histomorphological analysis were performed after the rabbits were sacrificed., Results: All the rabbits survived the operation and the incisions healed smoothly. No significant difference was noted in the serum calcium level between 1 day before operation, 1 week and 4 weeks postoperation. BMC in the defects of the rabbits with NPCB grafts increased more rapidly than that in the control group 6-12 weeks after the operation and began to decrease after 12 weeks. Gross, X-ray and histological observations revealed that NPCB possessed osteoconductive activity and new bone ingrowth in the implants was found during the whole experiment. At 16 weeks, the defects grafts were almost completely repaired with NPCB while the defects in the control group remained nonunion. Biodegradation of the implants was observed early at 6 weeks, with numerous macrophage and multinuclear giant cells containing phagocytosed NPCB particles around the implants at 12 weeks, but NPCB remnants were still visible at 16 weeks., Conclusion: As a bone substitute, NPCB possesses good biocompatibility, biodegradability and osteoconductive activity.

Objective: To investigate the distribution of -477C/T single nucleotide polymorphisms (SNP) in the promoter region of ATP binding cassette transporter (ABCA1) gene and its relation to plasma lipid levels in normal Chinese Han population., Methods: The three genotypes of -477C/T polymorphisms in the promoter region of the ABCA1 gene were detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 113 normal Chinese Han subjects., Results: -477C/T SNP was present in normal Chinese Han population, and 37.2% (42) of the examined subjects belonged to the genotype of CC, 46.9% (53) belonged to CT and 15.9% (18) to TT. The individuals with the TT genotype had a lower plasma high-density lipoprotein cholesterol (HDL-C) level than those with the CC genotype (P<0.05). No association was found between the genotypes and plasma levels of total cholesterol, triglyceride, low-density lipoprotein, very low-density lipoprotein and body mass index., Conclusion: The TT genotype significantly influences the plasma levels of HDL-C in normal Chinese Han individuals.

Objective: To investigate the expression efficiency of human platelet-derived growth factor B-chain (PDGF-B) gene in yeast and assess the activity of the expressed product., Methods: A full-length complementary DNA of human PDGF-B gene was amplified from the total RNA extracted from human vascular endothelial cells using reverse transcription (RT)-PCR and then cloned into pGEM-T vector. The PCR products with specific primers were recombined into yeast expression plasmids pMETB or pMETalphaA, followed by identification with restriction endonuclease., Results: The 578 bp fragment encoding mature PDGF-BB peptide with signal peptide and the 340 bp fragment without signal peptide were identified and verified by restriction endonuclease mapping and sequencing, and two yeast expression vectors pMETB-PDGFB(1) and pMETalphaA-PDGFB(2) were reconstructed., Conclusion: The yeast expression vectors containing human PDGF-B gene have been successfully constructed for further studies of gene expression in yeast.

Objective: To investigate the in vitro biocompatibility and degradation of nacre/polylactic acid composite artificial bone (NPCB) grafts., Methods: Human osteoblast cells were cultured with NPCB discs for observation of the morphological features and cell proliferation by optical microscope and scanning electron microscope. The mass loss of NPCB discs and pH variations of the saline in which the discs were immersed were examined every 2 weeks in a course of 16 weeks in vitro., Result: Compared with the negative control group, NPCB showed no visible cytotoxicity and facilitated the growth and proliferation of the osteoblast cells. As the immersion prolonged, gradual decrease in the mass of NPCB was observed accompanied by regular pH alteration of the saline., Conclusion: NPCB possesses good in vitro biocompatibility and may be gradually degraded.

Objective: To evaluate the clinical application of BACTEC MGIT 960 system and molecular identification of mycobacterium species in diagnosis of spinal tuberculosis., Methods: Thirty-one specimens were obtained from patients with spinal tuberculosis, followed by culturing with BACTEC MGIT 960 system and in Löwenstein-Jensen (L-J) medium respectively. Mycobacterium species of the clinical isolates were identified with PCR amplification of IS986 and PCR-single-strand conformation polymorphism (PCR-SSCP) analysis of 16S rRNA, with the conventional identification approach serving as control., Results: The positivity rates of mycobacterium culture with BACTEC MGIT 960 system and L-J medium were 83.87 % and 61.29 % respectively. The average detection time with BACTEC MGIT 960 were 11.3 d, 15.4 d shorter than that with the L-J medium (26.7 d). The genetic identification of mycobacterium species was more rapid and accurate with consistent results with that from conventional method., Conclusion: BACTEC MGIT 960 system is preferable for detecting mycobacteria in spinal tuberculosis. The combined application of this instrument with genetic identification of mycobacteria is an effective strategy for the bacteriological diagnosis of tuberculosis.

Objective: To explore a new bone substitute for bone grafting and evaluate its properties., Methods: Pressurized molding of nacre, polylactic acid and NaCl that were proportionally mixed was performed to obtain the bone grafting material, and its properties as porosity, pore size and mechanical strength were compared with those of the material prepared by solvent casting., Results: Compared with that of the material made by solvent casting, the mechanical strength of the new artificial bone material was 10-fold stronger with an average porosity rate of 47.65%, pore size of 218.83 micrometer compressive strength of 16.10 MPa and flexural strength of 60.18 MPa., Conclusion: The new technique adopted in this study can effectively enhance the biomechanics of the artificial bone material, which can be suitable for repairing bone defect.

Objective: To evaluate the therapeutic effect of several internal fixation methods in the surgical treatment of thoracolumbar spine and spinal cord injury (SSI-TL)., Methods: In the 166 SSI-TL cases included in this retrospective analysis, 37 had vertebral body burst fracture, 109 had vertebral body compression fracture (with compression to a degree over 50%),14 had vertebral body fracture and dislocation and 6 had multilevel vertebral fractures or jumping fracture. In view of the spinal cord injury 59 belonged to Frankel grade A, 46 grade B, 42 grade C and 19 grade D. Posterior decompression, reduction and internal fixation were performed in 122 patients and the other 44 underwent anterior decompression, reduction and ilium bone grafting., Results: Follow-up study for 3 to 18 month was conducted in 123 cases, in which RF screws cracking occurred in 4 cases, Harrington upper hook dislocation in 5 cases and Harrington rod cracking in 6, while the rest cases were free of theses incidents. In terms of the function recovery of the spinal cord, 88 cases showed improvement of the spinal cord and cauda equina of 1 to 3 Frankel grades, leaving only 35 lingering in grade A., Conclusion: Decompression should be performed at early stages of SSI-TL, and employment of various internal fixation instrument helps maintain and enhance spinal stability, preventing secondary lesion of the spinal cord and promoting the function recovery of the injured spinal cord.

This study was designed to observe the changes in the body temperature and erythrocyte sedimentation rate of patients with thoracolumbar tuberculosis who received anterior interbody autograft and internal fixation. The observation conducted in 21 cases establishes the 2 parameters as simple and reliable indicators for post-operative assessment of the patients.