Search Results

Objective: To explore and evaluate the biomechanic relationships between different depth of pedicle screw penetration with the sagittal plane reconstruction in thoracolumbar fracture. Methods:Six fresh cadaveric specimens of lumbar spine from L_1 to L_3 were used to make the model of thoracolumbar fracture. The system of universal spine system( USS )pedicle screw was adopted with the 6 mm diameter of screw. Each of two Schanz screws was implanted into the pedicles of L_1 and L_3 A canulated screw was fixed into the former of vertebral body in L_1 and L_3, and the distance of the two canulated screws was taken as the normal height. The axial loads were given while the pedicle screws were implanted at the depth of D1, D2 and D3, and the distance of the two canulated screw was measured as well as the distance was reduced to the normal height by axial load. The index measured included of the depth of pedicle screw penetration, the height of fractured vertebral body and afterload. Results: Along with the increasing of afterload, the height of injured vertebral body was increased accordingly, but the extent was different at three depth of pedicle screw penetration (D1, D2, and D3). While the injured vertebral body was reduced totally (reduced distance 0.00 mm), there was (2 630±13) g of afterload needed in Dl depth, and (2 339±61) g and(2 221± 164) g of afterload in D2 and D3 depth respectively. There was significant difference in distance between D1, D2 and D3 (P< 0.01), however, no significant difference between D2 and D3 (P> 0.05). Conclusion: There is a relationship in the depth of pedicle screw penetration, the capacity of reduction and sagittal plane reconstruction. The depth of pedicle screw had a significant effect on the capacity of reduction for the injured vertebral body, which would be the best option in biomechanics when the pedicle screw was implanted more than 1/2 pedicle or all of it.

8.Reporter cell line-based screening for anti-varicella-zoster virus compounds

Xiaoxia LI ; Weifang SONG ; Guanqing WANG ; Zhenling LU ; Jiankun HUANG ; He WANG ; Inoue NAOKI

Chinese Journal of Microbiology and Immunology 2011;31(8):745-750

Objective To establish a novel method to screen for anti-varicella-zoster virus (VZV) compounds with our previously generated reporter cell line for VZV, MV9G. MethodsMV9G cells were directly infected with cell-free virus of Oka vaccine strain (vOka) for 2 hours( CFV direct-infection) or cocultured with vOka-infected MeWo cells containing cell-associated virus for 48 hours (CAV co-culture) to promote expression of the reporter gene firefly luciferase. Antiviral compounds including heparin, mannose-6-phosphate( M-6-P), acyclovir( ACV ), resveratrol and roscovitine were added in the medium before or after the virus infection. Inhibitory effects( IC50 ) of the antiviral compounds were analyzed by comparing firefly luciferase activities of MV9G cells in the presence of antiviral compounds with those in the absence. Results Antiviral compounds inhibited luciferase activities of MV9G cells activated by CFV direct-infection and/or CAV co-culture in different levels. The reductions of luciferase activities statistically correlated with those of viral foci shown by immunostaining with a monoclonal antibody against VZV immediate early 62 antigens (IE62) in controls. Among these compounds, heparin, M-6-P, and 2.5 μmol/L of roscovitine inhibited CFV-activated more strongly than CAV-activated luciferase activities, whereas ACV and resveratrol inhibited CAV-activated more strongly than CFV-activated luciferase activities. Cell-associated ACV-resistant strains,Kanno and rOka YSR, activated luciferase activities of MV9G cells, too. However, the inhibitory concentrations (IC50) of ACV to the ACV-resistant strains were much higher than those to the ACV-sensitive strains,pOka and CaGu. ConclusionThe CFV direct-infection and CAV co-culture assays were useful to screen for antiviral compounds targeting the early and late phases of VZV infection, respectively. The VZV reporter cell-based assays may provide a simple, rapid, sensitive, and high-throughput method to screen for anti-VZV compounds.