BACKGROUND: There is no any mature and complete system to repair nerve tissue after segmental injury due to particularity of nerve tissue regeneration. Using tissue-engineering technique to solve this problem is difficult and challenged.OBJECTIVE: To research an artificial nerve bridging substance in application of repairing nerve injury on clinic and obverse its microcosmic spatial structure at the same time.DESIGN: Open experiment.SETTING: Orthopaedic Research Institute, Xijing Hospital of the Fourth Military Medical University of Chinese PLA.MATERTALS: The experiment was carried out in the Orthopaedic Research Institute, Xijing Hospital of the Fourth Military Medical University of Chinese PLA from November 2001 to January 2003. CollagenⅠ, collagen Ⅳ and gelatin were provided by Sigma-aldrich Company, USA.METHODS: Establishment of bridging substance: Collagen Ⅰ (65.53%) and collagen Ⅳ (32.77%) were added into 0.05 mol/L acetic acid solution, respectively; and then, two suspensions were mixed together and stirred at 4℃. The suspension of collagen and heparin sulfate was pumped, held still and poured into silica gel tube with bore of 3 mm.Continuously, two ends of tube were enclosed and suffered from cold drench and mold at five various speeds. General observation was done. Composites were intercepted cross section, vertical section and 45° section for observation by optic microscope at different speeds of 10×10-5 m/s, 5×10-5 m/s, 2.5×10-5 m/s, 1.0×10-5 m/s and 1.0×10-6 m/s; meanwhile, interior structure of microtubule was observed with scanning electron microscope. Interior diameter of microtubule was calculated as the following formula: actual aperture = (magnification × area of microtubule) ÷ (length of guage × perimeter of aperture).MAIN OUTCOME MEASURES: ① General observation; ② observation with microscope; ③ observation with scanning electron microscope and interior diameter of microtubule.RESULTS: ① General observation: Models were regular cylinders and had symmetrical features. Flexility was wonderful,texture was well-proportioned, and elasticity was strong. ② Results of optic microscope: Structure of external surface was completely blocking without any poricidal dehiscence. Surface was smooth and had good continuity. ③ Results of electron microscope: External surface shaped like terrace tile; asides, interior structure of microtubule was average and its courser was coincident and parallel to each other. Microtubules with longitudinal courser were independence on each other. The structure was blocking and did not connect to each other. This was as the same as courser of nerve fibrous bands of organis. Cross section of interior microtubule was general round and regular, and the diameter was average. Interior microtubule had groat continuity without breaks or transection. Trabeculae of microtubule also had groat continuity,and its surface was smooth. Interior diameter of microtubule ranged from 197.3 μm to 258.8 μm.CONCLUSION: Nerve bridging substance is made of collagen and gelatin which are characterized by groat compatibility and degradation after mixture, lysis and cold drench, It has singly longitudinal microtubule and microstructure of high imitation by normal nerves, so nerve bridging substance can be used in basic researches and repair nerve injury on clinic.

Objective To investigate the predictive value of heart rate variability to,and its correlation with ventricular arrhythmias in patients with structural heart disease.Methods 24 hours ambulatory electrocardiogram monitoring was administered during March 2012 and October 2013,and standard deviation of the NN interval (SDNN) in the time-domain analysis and sympathetic/vagal ratio in the frequency domain analysis were collected and retrospectively analyzed in 300 patients.Results The incidence rate of ventricular arrhythmias was higher in patients with structural heart disease in SDNN ＜100 ms group than in control group [4.1％ (3/74) vs.39.5％ (45/114),P＜0.01].The sympathetic/vagal ratio was significantly higher in group with structural heart disease and ventricular arrhythmia than in control group(19.9 ±2.3 vs.10.1 ±1.7,P＜0.01)The time-domain index SDNN was negatively correlated with the frequency domain index (sympathetic/vagal ratio) (r=-0.819,P ＜0.01).Conclusions SDNN ＜100ms and the increased sympathetic/vagal ratio can be considered as the predictors of ventricular arrhythmias in patients with structural heart disease.

Objective To establish and analyze a mouse model of Staphylococcus aureus?induced arthritis ( Staphy?lococcus aureus septic arthritis, SA) , and provide an animal model for arthritis mechanism research and drug development. Methods Mice were immunosuppressed with cyclophosphamide, then intravenously inoculated with Staphylococcus au?reus. The gross characteristics of the joints were observed, the arthritis indexes were analyzed, and the pathological scores of the model mice were evaluated. Results From the first day after bacterial inoculation, the mouse joints were swollen. Pathological examination revealed lesions varying from mild and disarranged joint synovial hyperplasia to synovial thickening and intra?articular invasion, and increased neutrophil infiltration. Conclusions A mouse model of Staphylococcus aureus?induced arthritis is successfully established in this study. This model can be developed in a relatively short time, can not only simulate the clinical symptoms and signs and disease progression of human arthritis, but also to a certain extent reflects the etiology, infection and immunological mechanisms of human arthritis.

Objective To investigate the changes of coagulatory function in septic rats induced by cecal ligation and puncture(CLP). Methods Cecal ligation and puncture(CLP)were performed to induce sepsis in SD rats. Coagulation indexes were detected at 8,16 and 48 h after operation, and histopathological changes of the lung, kidney, liver and spleen were examined using HE staining. Results The 12-day survival rate of the CLP-induced septic rats was 30%,with an acute onset and high mortality. In the acute phase of disease development of the CLP rats, the activated partial thromboplastin time(APTT)was prolonged(P<0.05)at 8 h,the prothrombin time(PT)was prolonged at 16 h (P<0.05), the factor XII activity in the endogenous coagulation pathway and the factor VII activity in the extrinsic coagulation pathway showed a transient inhibition, the thrombin time(TT)was prolonged at 48 h(P<0.01), and the content of fibrinogen(FIB)was increased gradually from 16 h(P<0.001). Among the other important coagulation and anticoagulation indexes,the number of platelets(PLT)was decreased gradually from 8 h(P<0.01),while the number of vWF:Ag increased gradually from 8 h(P<0.001). The D-dimer amount gradually increased from 16 h(P<0.05),and the amount of PS:Ag significantly decreased until 48 h(P<0.001). However, there was no significant change in the antithrombin-III(AT-Ⅲ)content. The histopathological examination showed that there are different degrees of damages in the lung,kidney,liver and spleen tissues,but no obvious venous thrombosis and bleeding were found. Conclusions In the acute phase,there is coagulatory dysfunction in the septic rats,however,no histopathological changes such as venous thrombosis and bleeding were observed in the lung,kidney,liver and spleen tissues due to coagulatory dysfunction.

Objective Previous studies suggested that overerpression of Slit2 results in abnormal Alzheimer's disease-like behavior and cognition impairment in mice. The aim of this study is to investigate the relationship between overerpression of Slit2 and accumulation and clearance of amyloid-β in aging mice by comparing the differential expression of genes for accumulation and clearance of amyloid-β in aging Tg-Slit2 and Tg-2576 mice. Methods 14-month old male C57BL/6, Tg-Slit2 and Tg-2576 mice were used to detect the expression of Aβ1 - 40 and Aβ1 - 42 in brain by immunohistochemistry. Further, the total RNA in the brain of these mice were extracted, identified and inversely transcripted to cDNA, then the cDNA was detected by PCR array. The expression of genes in the brain of Tg-Slit2 and Tg-2576 mice were analyzed. Results Comparing with the Tg-2576 mice in the same age, accumulation of Aβ was not found in the brain of Tg-Slit2 and C57BL/6 mice. The result from PCR array analysis showed that comparing with the same aged C57BL/6 mice, there were 16 up-regulated genes and 8 down-regulated genes in the brain of Tg-Slit2 mice and 14 up-regulated genes and 17 down-regulated genes in the brain of Tg-Slit2 mice. The expression of amyloid beta precursor protein (APP) in the brain of the three group mice was not changed. The expression of presenilin 2 ( Psen2) related with Aβ production was significantly up-regulated in the Tg-2576 mice. In addition, the expression of low density lipoprotein receptor-related protein ( LRP) 6 and 9 were markedly decreased in the Tg-2576 mice. Notably, these genes were not changed in the brain of the aging Tg-Slit2 mice. Conclusions The accumulation of Aβ in the brain are not found in 14-month Tg-Slit2 mice, In addition, different from Tg-2576 mice, the significant changes of expression of Aβ-related genes is not found in the brain of Tg-Slit2 mice.