BACKGROUND: Posterior pedicle screw fixation is a common method for treatment of thoracolumbar compression fractures. The fixation method contains long-segment fixation, short-segment fixation and vertebral fixation. Clinical effects of vertebral fixation and inter-vertebral short-segment fixation for treating thoracolumbar fractures remain unclear. OBJECTIVE: To compare the stability of posterior vertebral fixation and inter-vertebral pedicle screw fixation for treating thoracolumbar compression fractures. METHODS: Clinical data of 46 patients with thoracolumbar compression fractures were retrospectively analyzed. According to the fixation methods, they were divided into the vertebral fixation group (n=21) and inter-vertebral fixation group (n=25). The operation time, intraoperative bleeding, intraoperative blood transfusion, the time of lying in bed, vertebral Cobb angle, anterior vertebral height and visual analog scores were evaluated for a long time. RESULTS AND CONCLUSION: (1) During repair, in both groups, operation time, intraoperative bleeding and intraoperative blood transfusion were better in the inter-vertebral fixation group than in the vertebral fixation group (P < 0.05-0.01). The time of lying in bed was better in the vertebral fixation group than in inter-vertebral fixation group (P < 0.01). (2) No significant difference in Cobb angle and anterior vertebral height was detected before and after treatment and during repair in both groups, but final fol ow-up and fol ow-up loss were better in the vertebral fixation group than in inter-vertebral fixation group (P < 0.05-0.01). (3) No significant difference in visual analog scores was detected before and after treatment in both groups. Visual analog scores were better in the vertebral fixation group than in the inter-vertebral fixation group (P <0.01). (4) These results suggested that the two fixation methods obtained satisfactory repair effects in long-term fol ow-up. The dominance in maintaining the height and curvature of the spine was more obvious in the vertebral fixation group than in the inter-vertebral fixation group. The vertebral fixation can be more effective to reconstruct the spinal physiological sequence and restore its stability. After repair, low back pain can also be effectively control ed.

Aim To explore the effects of Baixiangdan capsule on learning and memory in PMS rat model with liver-qi invasion syndrome. Methods Liver-qi inva-sion rat model was prepared using foot-shock and noise stimulation, and then the model was treated with drugs, finally all the group of rats were evaluated using open-field test. We also detected learning and memory function of PMS liver-qi invasion rats model using Y-maze, new-object recognition and Morris water maze test. Results Compared with the normal group, the total distance increased significantly, number of crosses into the central area and duration of movement in the central area decreased significantly in model group. The total distance decreased significantly, number of crosses into the central area and duration of movement in the central area increased significantly in Baixiang-dan treatment group compared to the model group, and the total distance decreased significantly in fluoxetine treatment group compared to the model group. Com-pared with the normal group, DI decreased significant-ly in model group, and DI increased significantly in Baixiangdan treatment group. During place navigation training, the model group’ s escape latency was obvi-ously delayed on 2nd, 4th day. Compared with the model group, Baixiangdan and fluoxetine treatment group’ s escape latency was obviously reduced. During spatial probe test, compared with the normal group, the escape latency was obviously delayed, and the number of crossing platforms was significantly reduced in the model group. Compared with the model group, the number of crossing platforms significantly increased in Baixiangdan treatment group. Conclusion PMS liver-qi invasion rat model presents learning and memo-ry damage, which could be improved by Baixiangdan capsules, and the treatment effect may be superior to that of fluoxetine.

Objective TNF-related apoptosis-inducing ligand(TRAIL)was a new member of TNF family.It could quickly inactivate tumor cell originated from different tissues but no effects on normal tissue in vitro.Osteosarcoma was the most common primary malignant bone tumor with the survival rate of 5years no more than20%after simple surgical management.The induced apoptosis and selective cytotoxicity of human soluble TRAIL for MG -63cell line were investigated in order to explore the feasibility of sTRAIL in clinical treatment of osteosarcoma.Methods sTRAIL-mediated cytotoxicity by MTT assay in MG-63osteosarcoma cell line,MRC-5human diploid lung cell line and L-02fetus hepar cell line were assessed,apoptotic cellular morphological transformation by phase contrast microscope and electron micro-scope was observed.The expression of TRAIL receptors mRNA in the cell lines was examined by RT -PCR.The apoptotic rates of MG-63cell line were shown by flow cytometry.Moreover,the apoptosis of MG-63cell line induced by sTRAIL was confirmed by terminal-deoxynucleotidyl transferase mediated nick end labeling(TUNEL).Results MG-63,MRC-5and L-02cell lines were treated for 24hours with dif ferent concentrations of sTRAIL and the inhibitive rates of sTRAIL were evaluated with MTT assay,the in hibitive rates of 500ng /ml,1?g /ml ,2?g /ml and5?g /ml TRAIL inducing MG-63osteosarcoma cell line were10.1%,24.3%,50.6%and more than95%respectively.By flow cytometry,an obvious apoptosis peak ahead the diploid peak was obtained when MG-63cell line incubating with2?g/ml TRAIL for 6hours,howev er,the consequences of MRC-5and L-02cell line were non-differentiated.Therefore,MG-63cell line was significantly sensitive to sTRAIL-mediated apoptosis,but MRC-5and L-02cell line were resistant to sTRAIL-induced cell death.Under phase contrast microscope,when MG-63cell line were treated by sTRAIL,some cells began to became small and round in3to8hours.In24hours a large number of cells exfoliated and drifted in culture medium.Moreover,karyopyknosis and crescent aggregation of chro-matin were observed by electron microscope.By RT-PCR,the expression of TRAIL-R1,R2and R3but not R4mRNA on MG -63and MRC -5cell line were observed,and there were the expression of TRAIL-R1,R2,R3and R4mRNA on L-02cell line.In TUNEL assay,the nucleus of the apoptotic cells became brown or yellow.Conclusion TRAIL is able quickly to kill MG-63osteosarcoma cell line in vit-ro.Fur thermore,TRAIL is non significant cy-totoxic for normal tissue.TRAIL or TRAIL com bined with chemotherapy and radiotherapy is a potential and valuable proposal for clinical treatment of osteosarcoma.

Reform was made on traditional education mode based on the criterion of undergraduate medical education at home and aboard.The reform includes the changes in teaching content,teaching methods and assessment methods in an aim to establish independent learning mode,cultivate students' self-study ability,initiative spirit and innovation ability.

Objective To explore indications for replantation and amputation of complex severed lower legs. Methods Fifteen lower legs in 25 cases with complex severed lower limbs were replanted including four finally amputated again, and other 10 legs were amputated directly after trauma. Those with successful replantation were repaired with microsurgical technology and limb lengthening procedure for complications such as soft tissue defect, bone defect and limb shortening. The amputated cases were fitted with prosthetic limb after wound healing. Results All cases were followed-up for three to 10 years (6.4 years in average), and 11 lower legs were survived in 15 replanted cases and other four were finally amputated and fitted with prosthetic replacement. The limbs of those with successfully replantation shortened to varied extent, and one can be categorized as grade Ⅰ, four as grade Ⅱ, four as grade Ⅲ and two as grade Ⅳ, according to Chen's classification of function evaluation for replanted limbs. Appearance of prosthetic limbs in 14 cases had no significant difference from the normal, and 12 of them could walk with load and two had slight claudication. Those with prosthetic limbs were more satisfactory than those with replantation of the limbs. Conclusion Replantation for complex severed lower legs should be comprehensively considered based on mangled extremity severity score (MESS), their local condition and function prognosis.

Objective To investigate the experiment effects of rabbit joint articular cartilage defects repaired by thermosensitive CS/PVA composite hydrogel engineered hTGF-β1 transfected bone marrow mesenchymal stem cells. Methods Bone marrow mesenchymal stem cells were isolated and cultured in vitro. The positive rate of transfection was defected by cell immunohistochemistry methods after Ad-hTGF-β1 transfected for 1 week. Twenty-four adult New Zealand white rabbits with full articular cartilage defects were randomly divided into 4 groups, each group had 6 animals, both hind limbs were used in the experiment. Group A: hydrogel combined with transfected cells; Group B: hydrogel combined with untransfected cells; Group C: hydrogel group; Group D: blank control group. Specimens and histological observation were used to evaluate the repair effect after 16 weeks according to Pineda's score. Results The positive rate of hTGF-β1 expression in BMSCs was about 85.4% after transfection. After 16 weeks the defects of group A were repaired by cartilage-like tissue, the cell arrangement and densities of regenerated cartilage were similar to normal cartilage, type Ⅱ collagen immunohistochemistry were positive. There was a significant difference in Pineda's score compaired with other groups (P ＜ 0.05). Conclusion Rabbit articiular cartilage defects could be repaired by CS/PVA hydrogel engineered hTGF-β1-transfected bone marrow mesenchymal stem cells.

Objective To investigate the composite of chitosan(CS) and polyvinyl alcohol (PVA) as scaffold carrier for rabbit chondrocytes nurture and growth.Methods The third passage of chondrocytes were seeded in CS/PVA gel scaffold and 24,48 and 72 h after which cytoactive and toxicity were determined by MTT respectively.After one,two and three weeks,the growing status and morphology of chondrocytes in CS/PVA gel were observed with scaning electron microscope (SEM) and laser confocal scanning fluorescence microscope (LCSM).Results The third passage of chondrocytes in CS/PVA gel scaffold remained high proliferation ability.MTT measuring cell activity and virulence,the result showed that the number of cells obviously increased with the time,with statistical significance of difference between each groups (P＜0.05),without side effect to cells by the material.Observation of scaning electron microscope and confocal laser scanning fluorescence microscope showed that chondrocytes grew well with the scaffold of CS/PVA gel.Conclusion CS/PVA mixed gel material can be used as scaffold for rabbit chondrocytes growing for repairing cartilages defect in tissue engineering.

Objective To assessed the ability of FK506 and antilymphocyte serum(ALS) to induce mixed chimerism and tolerance for knee composite tissue allograft in rabbits without chronic immunosuppression. Methods Male Flap-eared rabbits were used as donors,and female New Zealand white rabbits were used as recipients. Vascularized heterotopic knee allotransplantation was performed. Treatment consisted of ALS(1 ml/kg) only,FK506(0.5 mg/kg) only and a combination of FK506 and ALS which were administered 24h before transplantation. ALS was administered intraperitoneally every day in the first three days. FK506 was administered gastric intubation every day for fifteen days. Survival times of knee allografts were observed. Donor specific hematopoietic chimerism and histology sections were tested. Results Survial time of knee allografts with ALS single was(17.4?1.8)d,and(23.8?1.5)d with FK506 single,(40.4?2.9)d with FK506 and ALS,contrasting with(13.6?0.8)d of control. Chimerism rate show a stabilization of 3 weeks above 10% after protocol discontinue in groups with FK506 and ALS. Conclusions Short-term administration of FK506 and ALS in this ways prolong survival time of vascularized knee allograft in rabbits and could maintain mixed chimerism and tolerance for 3 weeks.

In order to investigate the strength, structure and cell cytocompatibility of injectable thermosensitive chitosan (CS)/poly(vinyl alcohol) (PVA) composite hydrogel, chitosan hydrochloride solution was transferred to a neutral pH and mixed with different proportions of PVA, then the gelation time and strength of these different hydrogels were tested and spatial structures were observed under a scanning electron microscopy (SEM) after freeze-drying. The cytocompatibility of the hydrogels was evaluated through cytotoxicity test and three-dimensional culture with bone marrow mesenchymal stem cells. The results showed that the CS/PVA solution kept in liquid state at low temperature (0-4 degrees C) and turned into transparent elastomer about 15-20 min at 37 degrees C. Gelation time was prolonged, the strength increased and porous structure became dense with the PVA content increased in the mixed hydrogel. The cytotoxicity grades of these gels were from 0 to 1. Rabbit bone marrow mesenchymal stem cells could survive and proliferate in the gel within 3 weeks, and the gel had good cytocompatibility. It was concluded that thermosensitive CS/PVA composite hydrogel not only has interpenetrating network structure and better mechanical strength, but also has good cytocompatibility, and may be used as an injectable scaffold for tissue engineering.

In order to improve the teaching quality of seven-year program courses,and by adopting LBL,PBL and CBL,we develop a comprehensive teaching mode helpful to the develop-ment of students.This teaching mode,which has better teaching effect than the traditional one,can pay attention to teaching purposes,excitate the students'learning potential,lead them to study more independently.