Objective To assess the accuracies and feasibility of spine surgery assisted by different types of navigation system.Methods In experiment study,40 human cadaveric cervical spines were employed and 3.5 mm screws were placed into the C 3 to C 7 pedicles following five kinds of insertion techniques:blind screw placement(Group 1),assisted by X-ray fluoroscopy(Group 2),assisted by virtual fluoroscopy navigation system(Group 3),assisted by CT-based navigation system(Group 4),assisted by Iso-C 3D navigation system(Group 5).Thereafter,cortical integrity of every sample was examined by anatomic dissection.In clinical study,163 cases of spine operations assisted by different types of navigation were reviewed.The accuracies of screw placement were evaluated by postoperative CT or Iso-C 3D scan.Results In experiment study,there were 398 pedicles inserted.Group 1,the average operation time per sample was 27 minutes;36.3% of the screws were excellent,26.3% good,and 37.5% bad.Group 2,the average operation time was 112 minutes;44.9% excellent,37.2% good,and 17.9% bad.Group 3,the average operation time was 69 minutes;42.5% excellent,45.0% good,and 12.5% bad.Group 4,the average operation time was 98 minutes;87.5% excellent,12.5% good.Group 5,the average operation time was 91 minutes;90% excellent,10% good.In clinical study,272 screws inserted with virtual fluoroscopy navigation system,89.3% excellent,10.7% good.571 screws inserted with CT-based navigation system,84.9% excellent,14.4% good,0.7% bad.142 screws inserted with Iso-C 3D navigation system,95.8% excellent,4.2% good.Conclusion Computer-assisted navigation system enhances accuracies and further improves the safety of spine surgery,especially utilizing CT-based navigation system and Iso-C 3D navigation system.Iso-C 3D navigation method is better than the other two navigation methods.

Objective To study some biological properties of mouse bone marrow stromal cells(MSCs)and their ability to differentiate endothelial cells and surviving ability in ischemic tissue,and provide an experimental foundation for applying MSCs to ischemic repair.Methods After the tibias and femurs were dissected from 5-to 6-week-old mice from Jan.2005 to Nov.2005,the marrow was flushed out with ice-cold DMEM/F12 medium.The mononuclear cells of the marrow were obtained with density gradient centrifugation and the plated and cultured in DMEM/F12 medium.The cultured cells in vitro were induced with endothelial cell growth supplement.The ability of MSCs was also was examined in ischemic tissue.Results The adherent fibroblast-shaped cells approached confluence in single layer 12~16 d after plating.The cultured MSCs in vitro differentiated into endothelium.Numerous scattered DAPI-labeled cells were found in the specimen seven days after implantation,and hematoxylin and eosin staining of the adjacent section showed concordance between dense hematoxylin staining and presence of DAPI epifluorescence,and there was no obvious inflammatory response.Conclusion The subcultured MSCs possess potential to differentiate into endothelial cells.MSCs show stable growth in vitro,easy survival in the subculture and rapid proliferation in present culture condition.MSCs may be used in therapy for myocardium ischemia.

Objective:To investigate biomechanical changes of mandible in the impact injure simulated by finite element method (FEM).Methods:Mimics and Comsol software were used to build a FEM of human craniofacial bone based on CT scan data of a normal adult.LS-DYNA and Hypermesh software were used to simulate the impact with different quality,velocity and angulation pro-duced injures of human mandible,the biomechanical parameters of the mandible in the impact injury process were analysed.Results:A FEMof human maxillofacial bone was established,and the dynamic process of different impact force produced damage was simula-ted.Mandibular chin,angle and condylar neck was the stress concentrated area in the process of mandible injury.There was higher stress peak at the site which was closer to the impact position,the stress peak arrival time was also earlier.When the impactor with the same quality,the bigger the velocity,the greater the stress peak.When the impactor with the same velocity,the bigger the quali-ty,the greater the stress peak.When the impactor with the same velocity and quality,there was greater stress peak under the impact to mandible from angulation of 0 degree.Stress transfered to the surrounding bone from the impact position radially and gradually re-duced.The bone area with small cross-section was prone to high stress and more serious damage.Conclusion:The quality,the ve-locity,the impact angle and the impact site are the factors affecting the severity of impact injury.

Objective:To observe influence of simvastatin on p 27 protein (cyclin‐dependent kinase inhibitor ) expres‐sions of vascular smooth muscle cells (SMC) and endothelial cells (EC) in rats for screening new generation coating drugs of eluting stents .Methods :Primary aortic SMC and EC of rat were isolated and cultured by methods of adher‐ent and enzymatic digestion respectively .Which were inoculated on fibronectin -coated culture plates .α smooth muscle actin immunofluorescence staining was used to identify SMC ,and von Willebrand factor (vWF) immunofluo‐rescence staining was used to identify EC .SMC and EC were cultured for 24h with different concentrations of simv‐astatin (0.01 ,0.1 ,1 and 10 μmol/L) ,then Western blot was used to measure p27 protein expression .Results:Compared with blank control group ,0.01μmol/L simvastatin had no significant influence on p 27 protein expression of SMC ,but 0.1 ,1 and 10 μmol/L simvastatin significantly raised p27 protein expression of SMC [ (0.53 ± 0.08) vs .(0.86 ± 0.05) ,(1.20 ± 0.05) ,(1.60 ± 0.04)] , P< 0.01 all .Besides ,different concentrations of simvastatin had no significant influence on p27 protein expression of EC , P> 0.05 ,indicating that simvastatin only dose‐de‐pendently promoted p27 protein expression of SMC .Conclusion:Simvastatin dose -dependently promotes p27 pro‐tein expression of vascular smooth muscle cells without affecting p 27 protein expression of endothelial cells .So local application of simvastatin may inhibit restenosis and promote reendothelialization of injured vessels .

BACKGROUND:Autologous split-thickness skin grafting is the main therapy for burn repair at functional sites, which has achieved certain effects, but there are stil some deficiencies, such as poor texture, stiffness and poor toughness, as wel as severer hyperplasia that is easy to result in contracture deformity and poor functional recovery. OBJECTIVE: To analyze the clinical efficacy of skin co-transplantation on burn repair at functional sites. METHODS:Sixty patients with burns at functional sites (n=84) were randomized into two groups: co-transplantation of acelular dermis and autologous split-thickness skin in experimental group and autologous split-thickness skin graft in control group. Survival rate of skin flap and rate of secondary operation were compared between two groups. At 1 month after transplantation, Vancouver Scar Scale was used to assess skin color, thickness, blood vessel distribution and flexibility, and meanwhile, the severity of scar was determined. RESULTS AND CONCLUSION:The survival rate of skin flap was significantly higher in the experimental group than the control group (93%vs. 70%,P < 0.05), and the rate of secondary operation was significantly lower in the experimental group compared with the control group (0vs. 13%,P < 0.05). At 1 month after transplantation, scores on the skin color, thickness, blood vessel distribution and flexibility were al lower in the experimental group than the control group (P < 0.05), but the incidence of mild hyperplasia in the experimental group was significantly higher than that in the control group (52% vs. 29%,P < 0.05). These findings indicate that co-transplantation of acelular alogeneic dermis and autologous split-thickness skin for burn repair at functional sites can effectively enhance the survival rate of skin flap, reduce the rate of secondary operation, contribute to wound healing and reduce the severity of hyperplasia.

Tetrabromobisphenol A(TBBPA)is supposed to have potential thyroid disrupting activities due to its similar structure to thyroid hormones.TBBPA has been proved to show thyroid disrupting effects in vivo and in vitro studies.TBBPA might disrupt thyroid hormone system through transthyretin- and thyroid receptor-mediated pathways.The ability of TBBPA inducing the production of reactive oxygen species might be the extension of its thyroid disrupting activities.The thyroid disrupting effects of TBBPA might be closely related to its oxidative stress,reproduction toxicity and neurotoxicity.More experiments are required for the effects of TBBPA on the aquatic and amphibian animals.

Objective To construct the bait expression plasmid pGBKT7-GR of glucocorticoid receptor(GR)binding domain.Methods The fragments of GR binding domain was amplified by RT-PCR,and then was cloned into pMD18-T.After being verified by sequencing,it was subcloned into the bait expression vector pGBKT7.Then the bait vector pGBKT7-GR was transformed into AH109 yeast cells and the expression of the bait protein was analyzed by Western blot.Toxicity and self-activation of the bait protein were detected.Results GR binding domain was amplified and cloned into pMD18-T and pGBKT7 successfully.The bait vector was transformed into AH109 yeast cells successfully,without toxicity or self-activation.The expression of the bait protein was confirmed by Western blot.Conclusion The successful construction of bait expression vector of glucocorticoid receptor binding domain lays the foundation for constructing small molecule ligand yeast three-hybrid system.

Human Interleukin-11 (hIL-11) is a multifunctional cytokine which plays an important role in regulating the proliferation and differentiation of cells in the hematopoeitic,lymphoid system etc. To obtain the IL-1 1 cDNA, a primary culture of Chinese fetal lung fibroblast was prepared from fresh tissue. Then the human IL-11 cDNA without the N-terminal signal peptide sequence was cloned by RT-PCR from the cells induced by PMA. The sequnce indicated that there are three bases different from those previously reported,but with no change of the amino acids. The cDNA was inserted into the 3′ end of trxcA gene in thioredoxin gene fusion expression system pTRXFUS to construct the trxA and hIL-1 1 fusion expression vector, and expressed in E. coli. The fusion hIL-11 accounts for more than 20 % of the total bacteria proteins.The expression product is present in soluble forms and has the full biological and immunological activities.

Objective To develop a 3D finite element model for the human craniomaxillofacial region in an attempt to offer basis to the research of simulation of craniomaxillofacial injury.Methods A healthy adult male was submitted to head CT scan, and the data was imported into the Mimics 15.0 software for threshold segmentation and 3D reconstruction according to the classifications of bone tissue, skin tissue and subcutaneous tissue.The reconstruction data was imported into 3D reverse software Geomagic Studio 2012, and the images were optimized and the 3D model was generated.The three parts of the model were fitted according to the actual proportion using the 3D control software Solidworks 14.0, and then the boundary conditions were derived.Hypermesh 12.0 finite element processing software was used to build the volume mesh, and the model was established.Each layer of the model was given to the material parameters, and the simulation conditions were provided to test the model.Results This model was completely composed of volume meshes, including 214,250 hexahedral meshes and 411,920 nodes.This model can clearly show the stress distribution, the trend of fracture line, the displacement of fracture block of soft and hard tissue during the simulation, and the results are consistent with clinical practice.Conclusion A three-dimentional finite element model with good performance is established, which can be used for biomechamics simulation analysis of multiple sites on the head or the whole structure, and has a certain significance in clinical and scientific research.

Objective:To observe influence of simvastatin on differentiation ,proliferation ,migration and adhesion of marrow-derived smooth muscle progenitor cells (SPCs) and screen coated eluting stent drugs of new generation . Methods :The mononuclear cells (MNCs) were isolated from rat marrow by density gradient centrifugation method , and then plated on fibronectin-coated culture dishes ,after culture 8d ,marrow-derived SPCs were identified by α-smooth muscle actin (α-SMA) immunofluorescent staining and counted under inverted fluorescence microscope .The MNCs and adhesion cells were treated with simvastatin (0.01~10 μmol/L) respectively for 8 d and 24h .SPCs pro-liferation ,migration and adhesion were observed by Tritium thymidine (3 H-TdR) intake method ,modified Boyden chamber assay and adhesion assay .Results:Compared with control group (no simvastatin intervention ) ,0.01μmol/L simvastatin significantly inhibited the MNCs differentiation towards SPCs [ (85 ± 4) vs .(79 ± 5)] ,proliferation [ (4070 ± 184) vs .(3833 ± 126)] ,migration [ (44 ± 3) vs .(39 ± 3)] and adhesion of SPCs [ (59 ± 5) vs .(52 ± 4)] , P<0.05 all ,and number of SPCs significantly reduced along with simvastatin concentration increased (P<0.01) . Conclusion:Simvastatin could inhibit the differentiation ,proliferation ,migration and adhesion of marrow-derived smooth muscle progenitor cells .