Objective To supply safe mechanic refererence for reduction of thoracolumbar burstfracture with pediclc screws and lay biomechanic foundation for developing a new type of digitizing pediclc screws. Methods The change of stress and its scope of pediclc screws during reduction of thoracolumbar burstfracture were tested to determine the relationship of the degree of reduction with stress and strain. Results A total of 15 burstfracture specimens were obtained successfully. Stress was small and changed mildly at the beginning of reduction stage. Stress presented transparent elevation tendency at the stage of body height of 75% of intact until at the stage of 90%. When the height of vertebral body restored from 90% to 95%, the curve of stress changed gently. The maximum stress of left screw was 98.4?10.3 and the right was 101.2?13.4. The stress of bilateral screws did not differ significantly. It was calculated that the left strain was (34.64?3.84)N and the right one was (35.544?3.61)N, the moment was (5.20?0.58)Nm of the left and (5.33?0.54)Nm of the right. There was not significant difference between the strain and the moment of bilateral screws. Conclusion The safe range of reduction force is between 4.5Nm and 6Nm. The burstfracture of vertebral body can be both reduced successfully and prevented from overpropping.

BACKGROUND:Previous studies designed and made titanium metal rubber cervical disc prosthesis, and performed feasible studies on its effect on movement and stress distribution by replicating intervertebral discs. OBJECTIVE:To further observe the changes in the stability of goat cervical vertebra after metal rubber cervical disc replacement. METHODS:Nine goats were randomly divided into experimental group (n=6) and normal control group (n=3). Goats in the experimental group received metal rubber cervical disc replacement at C4/5segment. Goats in the normal control group did not receive any treatment. Radiographic data at anteroposterior and lateral position, hyperextension and excessive flexion were taken to measure intervertebral height, range of motion and intervertebral angle at C4/5 segment before operation, immediately, 4, 8, 12 weeks after operation. Subsequently, slicing and embedding of hard tissue at surgical segment, picric acid-acid fuchsin staining and scanning electron microscopy were conducted.RESULTS AND CONCLUSION:No significant difference in the intervertebral height and spinal range of motion at C4/5 segment at different time points was detected between postoperative results in the experimental group and preoperative results in the experimental group, normal control group. The intervertebral height at C4/5 segment was higher immediately, 4 and 8 weeks after surgery than preoperative result in the experimental group (P < 0.05). No significant difference in intervertebral angle at C4/5 segment was detectable between 4, 8 and 12 weeks postoperatively in the experimental group and normal control group (P < 0.05). At 4 weeks after surgery, bone did not contact with the edge of the prosthesis in the experimental group. At 8 weeks, the gap between bone and the prosthesis became smal, and some new bone attached to the edge of the prosthesis. At 12 weeks, a few osteoblasts were observed on the surface of the prosthesis. New osteogenic tissue grew into the prosthesis. Results suggested that metal rubber cervical disc replacement in the intervertebral space could maintain intervertebral height and range of motion in a short period, and tightly bind to the vertebral body.

Objective To compare the clinical effect and safety evaluation of three different dose regimens for treating children with viral encephalitis.Methods Totally 126 cases treated in Xi'an Central Hospital from January 2010 to December 2015 were randomly divided into observation group 1 (ganciclovir combined with gangliosides,42 cases),observation group 2 (ganciclovir combined with gamma globulin,43 cases),and control group (39 cases).The clinical effect and levels of NSE,inflammatory cytokine were compared in the three groups.Results The total effective rate in observation group 1 was 95.24％ and that of observation group 2 was 93.02％,which were significantly higher than that of control group (79.48％).The disappearance time of headache,fever,convulsions,clouding of consciousness,meningeal irritation sign,cerebrospinal fluid abnormalities,and length of stay in observation groups (both 1 and 2)were significantly shorter than those in control group (P ＜ 0.05);After therapy,the levels of NSE in three groups were obviously decreased compared with those before therapy (P ＜ 0.05),and those in observation group were significantly lower than the control group (P ＜ 0.05);the levels of inflammatory cytokine in all three groups were obviously decreased compared with those before therapy (P ＜ 0.05),and that of observation group 1 had no statistical difference with the normal group,whereas that in control group was significantly higher than the normal group (P ＜ 0.05).Conclusion Ganciclovir combined with gangliosides as well as ganciclovir combined with gamma globulin were both effective methods in treating children with viral encephalitis and could decrease levels of inflammatory cytokine.Ganciclovir combined with gangliosides could effectively repair nerve damage,which deserves clinical expansion.

BACKGROUND:As a bone scaffold material,β-tricalcium phosphate has good biocompatibility, osteoinductive, and biomechanical properties.
OBJECTIVE:To study the effect of al ogeneic osteoblasts compounded withβ-tricalcium phosphate in repairing rabbit radial defects.
METHODS:A total of 45 rabbit radial defect models were made and divided into three groups in random. Experimental group was repaired with the compound of al ogeneic osteoblasts andβ-tricalcium phosphate;
control group withβ-tricalcium phosphate;and blank control group with nothing. The new bone formation of each group was observed and assessed by X-ray and histopathological analysis at weeks 4, 8, 16 after implantation for evaluation of the bone repairing effect.
RESULTS AND CONCLUSION:With the repair time, the experimental group appeared to complete bone defect repair gradual y. By the end of 16 weeks, the X-ray showed that the bone cal us between the scaffold and the host was completely ossified, and bone defects were completely repaired in the experimental group. Histopathological observation showed continuous cortical bone formed in the defect area, and canal recanalization realized in the experimental group. Additional y, the repair effect in the experimental group was better than that in the control and blank control group at different time points (P<0.01). It is suggested that the al ogenic osteoblasts/β-tricalcium phosphate compound has the better effects on guiding bone regeneration and preventing from nonunion.

Objective To explore whether macrophage migration inhibitor factor (MIF)can protect human bone microvascular endothelial cells (HBMECs)from glucocorticoid-induced damage.Methods HUVECs were isolated from human femoral head.After HUVECs were cultured and identified,we constructed the ECs damage model with high-dose hydrocortisone.The cells were randomly divided into blank control group,low-dose MIF group,high-dose MIF group with corresponding treatment.Cell activity was detected by AlamarBlue in each group. The number of viable cells was detected in Live/Dead staining.The cell morphology was observed after cytoskeleton staining.Cell migration ability was compared by scratch test and the level of VEGF expression was detected by ELISA.Results Cell model was successfully constructed.The activity of cells in high-dose MIF group (178.3± 15.2)% was significantly higher than that in the control group (100±8.4)% and low-dose MIF group (149.1± 13.8)% (P<0.05).The number of viable cells in high-dose MIF group (139.5±14.3)% was higher than that in low-dose MIF group (121.3±12.9)% while the two groups had more viable cells than the control group (100± 8.4)% (P<0.05).The scratch test results indicated that cell migration ability in high-dose group was the strongest and the scratch disappeared at 24 hours after scratching.The expression of VEGF at 24 hours after intervention was (170±15.7)pg/mL in normal group,(328±25.3)pg/mL in low-dose group and (405±31.2)pg/mL in high-dose group.VEGF level was lower in low-dose group than in high-dose group (P<0.05),but higher than the normal group (P<0.01).Conclusion MIF can promote the proliferation and migration of ECs in a dose-dependent manner and upregulate the expression of VEGF.MIF can improve ECs damage induced by high-dose glucocorticoid.

Objective To investigate the repair effects of co-expression of the VEGF and BMP genes via an adeno-as-sociated viral vector on early steroid-induced avascular necrosis of the femoral head in rabbits. Methords To construct ani-mal model of early SANFH and screen by MRI. The SANFH animal were divided into rAAV-IRES-hrGFP(AAV-GFP), rAAV-hVEGF165-IRES-hrGFP(AAV-VEGF), rAAV-hBMP-7-IRES-hrGFP(AAV-BMP)and rAAV-hVEGF165-IRES-hBMP-7(AAV-VEGF/BMP)groups. The four group virus vectors were injected into core decompression region at the dose of 25μl/site after core decompression operation directly. Repair effects of rAAV vector on early SANFH in rabbits were evaluated by Western blot assay, HE staining, immunohistochemical staining, MRI, radionuclide bone scan, blood vessel counting detected by ink perfusion and fro-zen section, Micro-CT and biomechanical strength detection on the 12th week post-injection. Results Model success ratio was 73.33%. rAAV-hVEGF165-IRES-hBMP-7 virus vector efficiently expressed hVEGF165 and hBMP-7 genes on the 12th week after rAAV injection. hVEGF165 protein secreted in vivo promoted metabolism in core decompression region by increasing the quantity of new vessels and improving the blood supply;hBMP-7 protein secreted in vivo promoted new bone formation in core decompres-sion region by increasing bone mineral density and improving bone biomechanical strength. The AAV-VEGF/BMP group can pro-mote repair effects more effectively than AAV-VEGF group or AAV-BMP group. Conclusion The adeno-associated viral vectors co-expressing hVEGF165 and hBMP-7 can promote repair effects on early SANFH in rabbits by increasing the blood supply and strengthening the bone quality of femoral head.

ts the shear stress, thus, facilitates the union of fracture and the restoration of function.

To explore the effects of different doses of puerarin on proliferation of cultured vascular endothelial cells in vitro.

OBJECTIVE: To observe the promoting effect of arnebia root oils on expression of basic fibroblast growth factor (bFGF) in skin wound of rabbits and the histomorphological changes in the wound surface, and to discuss its mechanism. METHODS: Bilateral round skin wounds were made on the back of 15 rabbits. The three wounds on one side of the back of each rabbit were treated with arnebia root oils, while the three wounds on the other side were treated with vaseline in order to promote the wound healing. The histomorphology and ultrastructure under electron microscopy of the wounds, and the rate of wound healing were examined at different time. Western blotting assay was used to detect the expression of bFGF in the wound surface. RESULTS: The healing rate of the arnebia root oils-treated wounds was evidently higher than that of the vaseline-treated wounds (P<0.05). The quantities of fibroblast, collagen and capillary in the arnebia root oils-treated wounds were much more than those in the vaseline-treated wounds, and the expression of endogenous bFGF in the arnebia root oils-treated wounds was enhanced obviously as compared with that in the vaseline-treated wounds in different period of wound healing. There existed a parallel correlation between the expression level of bFGF and the rate of wound healing. CONCLUSION: The promoting effect of arnebia root oils on wound healing may be related to increasing the expression level of basic fibroblast growth factor in the skin wound.

BACKGROUND:Choosing internal fixator implants with good strength and stiffness is the key to repair femoral neck combined with ipsilateral subtrochanteric fractures. OBJECTIVE:To compare the biomechanical properties of different implant fixation for femoral neck combined with ipsilateral subtrochanteric fractures. METHODS:Totaly 24 adult antiseptic cadaver specimens were used to produce fracture models with femoral neck fracture combined with 5 cm of ipsilateral subtrochanteri medical cortical defect, and were divided into femoral proximal locking plate group, lengthening proximal femur anti-rotation intramedulary nail group and lengthening proximal femoral nail group according to the random number table method. The results of axial compression test, torsion test and axial compression failure rest in three groups were compared. RESULTS AND CONCLUSION: The axial compressive stiffness and failure load in lengthening proximal femur anti-rotation intramedulary nail group were significantly greater than those in femoral proximal locking plate group and lengthening proximal femoral nail group, and those in lengthening proximal femoral nail group were significantly greater than those in femoral proximal locking plate group (P < 0.05). The torsional stiffness in femoral proximal locking plate group was significantly greater than that in lengthening proximal femur anti-rotation intramedulary nail group and lengthening proximal femoral nail group, and that in lengthening proximal femur anti-rotation intramedulary nail group was significantly greater than that in lengthening proximal femoral nail group (P < 0.05). The indexes of biomechanical properties of specimens at the 4thand 8th weeks after fixation in three groups were slightly increased compared with those in 0 week after surgery, but the difference was no statisticaly significant (P > 0.05). These results demonstrate that to a certain extent, compared with the femoral proximal locking plate and lengthening lengthening proximal femoral nail, lengthening proximal femur anti-rotation intramedulary nail fixation for repair of femoral neck combined with ipsilateral subtrochanteric fractures has more biomechanical advantages.