Objective To evaluate the in vitro biological safety of acellular spinal cord scaffold so as to provide theoretical basis for constructing the ideal tissue engineering scaffold of spinal cord.Methods A piece of thoracic spinal cord for 2 cm removed from SD rats was harvested and then was treated by freezing and thawing and chemical extraction with 3% sodium deoxyeholate and 1 KU/ml DNaseI and RNaseA. Gross observation and histological examination of the acellular spinal cord scaffold were carried out to learn the condition of the extracellular matrix scaffold. The biological safety of the acellular spinal cord scaffold was evaluated. Results In cross section, network of the extracellular matrix was presented in the scaffold. The cells, myelin and axons disappeared after the spinal cord was treated with sodium deoxycholate, DNaseI and RNaseA. Typical network of empty tubes were viewed in longitudinal sections. General toxic reaction, pyrogen test, hemolysis test and cytotoxicity test were conforming to the standard of materials. Conclusion As neotype tissue engineering material, the acellular spinal cord scaffold has satisfactory biological safety.

[Objective]Using a procedure of chemical agent to remove the cells and myethin in spinal cord of rat and to prepare the scaffold of extracellular matrix,so as to obtain an ideal natural spinal cord scaffold to bridge the nerve gap.[Method]Rat spinal cord was cut and treated using the method of freeze thawing and chemical extraction(3%sodiumdeoxycholate and 1KU/ml DNaseI,RNaseA).Histology was exploited to evaluate the degree of acellular and the structure of the spinal cord scaffold.[Result]In cross section,network of the extracellular matrix was presented in the scaffold.The cells,myethin and axons disappeared after the spinal cord was treated with sodium deoxycholate and DNaseI,RNaseA.Typical network of empty tubes were viewed in longitudinal sections.[Conclusion]An ideal spinal cord scaffold can be produced with the method designed in authors experiment.This scaffold has similar three dimensional structure with normal spinal cord,which can be used as a graft to bridge the nerve gap directly or as a scaffold to implant the seeding cells in spinal cord tissue engineering.The experiment indicates that cells and myethin can be removed and the three dimensional structure be reserved by chemical extraction with 3% sodium deoxycholate and 1KU/ml DNaseI,RNaseA.Chemical extraction is an ideal method to prepare tissue engineer scaffold of spinal cord.

[Objective] To investigate the immunogenicity of the acellular spinal cord scaffold and to provide theoretical basis for its further application in tissue engineering.[Method]Acellular spinal cord(freeze thawing +3%sodiumdeoxycholate + DNaseI 、RNaseA)and fresh spinal cord of rats were implanted into paravertebral muscles of rats.The tissue was obtained at 1、2、3 and 4w after the operation,then the inflammatory reaction was evaluated by HE stain and the immunogenicity of acelular scaffold was tested by immunohistochemical examination of the intensity of CD3+ 、CD4+ and CD8+ cells that infiltrated the allografts.[Result]The bistological examination indicated that acellular spinal cord scaffold was surrounded by a amount of neutrophilic cells and lymphocytes one week postoperatively,yet two weeks postoperatively,there was only small amount of lymphocytes infiltration.Fresh spinal cord allograft elicited an intense acute inflammatory infiltrate,and two weeks later,there still had a mount of lymphocytes infiltration.The intensity of CD3+、CD4+ and CD8+ T cells that infiltrated the allografts was greatly lower in acellular spinal cord than that in fresh spinal cord.The mild cell-mediated host-graft immune rejection in acellular spinal cord was observed.[Conclusion]The acellular spinal cord scaffold has mild inflammatory reaction and immune rejection,suggestting it is qualified for some biological properties and it may be a potential alternative scaffold of tissue engineering.

Objective To compare the effect of 2 decellularizing methods,sodium deoxycholate plus Triton X-100 or plus DNase and Rnase,in the preparation of acelluar allograft spinal cord scaffold in order to provide an ideal natural spinal cord scaffold to bridge the nerve gap.Methods Spinal cord was removed from health rats,and then decellularized by the method of freeze thawing(immersing in 3% sodium deoxycholate followed by the mixture of 1?103 U/ml DNase and RNase),or by chemical extraction(immersing in 1% Triton X-100 and then 1% sodium deoxycholate).HE staining,myelin staining and scanning electron microscopy(SEM) were employed to evaluate the spinal cord scaffold after the 2 methods of decellularization.Results Both cells and myelin were completely decellularized with the 2 methods.In cross section,network of the extracellular matrix was presented without axon,sheath and cells nucleus being seen in the scaffold.Typical network of empty tubes were viewed in longitudinal sections.Conclusion An ideal spinal cord scaffold can be produced with these 2 decellularizing methods in tissue engineering.The scaffold made by the 2 methods have similar three dimensional structure with normal spinal cord,so can be used as a graft to bridge the nerve gap directly or as a scaffold to implant the seeding cells in spinal cord tissue engineering.

Objective To prepare the acellular scaffold of spinal cord and analyze its component.Methods The acellular scaffold was prepared with the freeze thawing and chemical extraction,its structure was observed by HE and SEM,its component was analyzed by immunohistochemistry.Results The cells,myelin sheath and axon of nerve fibers in the rat spinal cord were eliminated,but three-dimensional supports of extracellular matrix were reserved.The analytical results showed the component of the acellular spinal cord contain laminin,fibronectin and type Ⅳ collagen—the necessary components to facilitate and induce the regeneration of the injured nerves and enhance the adhesion and proliferation of cells.Conclusion The acellular spinal cord has three dimensional structure and contains several proteins related to the regeneration of the injured nerves and promotion of the survival and proliferation of cells.

Objective To investigate the effects of transplantation of oligodendrocyte precursor cells(OPCs) on the recovery of neural function in rats with spinal cord injury.Methods The spinal cord injury(T10) rat model was established by Allen's method of weight-drop injury.Ninety six SD rats were randomly divided into 4 groups(24 each): transplantation group,control group,injury-only group and sham-operation group.Seven days after spinal cord injury,the rats of transplantation group received OPCs transplantation,of control group were injected with equivalent saline,and of injury-only group were untreated.The effects of OPCs transplantation on neural functional recovery in spinal cord injured rats were measured by the behavioral test and assessments of motor evoked potentials(MEP) and somatosensory evoked potentials(SEP).Results Immediately after spinal cord injuries,the neural function of spinal cord of rats was markedly impaired.The results of behavioral test,MEP and SEP in injured rats were much worse than those in sham-operation group.Although the neural function in spinal cord injured rats improved in different degrees with the time,the results of behavioral test,MEP and SEP showed it was significantly better in transplantation group than that in control group.Conclusion The transplantation of OPCs may enhance the recovery of neural function of rats with spinal cord injuries.

BACKGROUND:Surgical treatment is often required for fractures of the cervical vertebrae. Anterior interbody fusion technology is stil the main method for the treatment of cervical degeneration or traumatic instability. Here, the self-made oval al ogeneic bone pad can adapt to different height and width of the intervertebral space, in line with the physiological shape of the intervertebral space. OBJECTIVE:By comparison with autogenous iliac crest bone, to evaluate various types of self-designed al ogeneic bone pads on anterior cervical interbody fusion. METHODS:From January 2009 to December 2013, 58 patients with cervical disc herniation were enrol ed and subjected to cervical discectomy and anterior cervical interbody fusion. According to different bone grafts, these patients were divided into al ogeneic bone pad and autogenous iliac bone groups. The course of disease was 12 to 24 months. The postoperative effect was measured by Japanese Orthopaedic Association (JOA) score, cervical fusion rate, fusion time, operative time, blood loss and rejection rate. RESULTS AND CONCLUSION:At 6 months postoperatively, the JOA score of two groups had no significant difference at 6 months after treatment (P>0.05);the cervical fusion rates were 83.7%and 87.8%, respectively, in the al ogeneic bone pad and autogenous iliac bone groups, with no significant difference (P>0.05). Fusion time was higher in the al ogeneic bone pad than in the autogenous iliac bone group (P<0.05). The internal fixators in the two groups were firmed without loosening, and there was no rejection during the fol ow-up. Compared with the autogenous iliac crest bone, anterior cervical interbody fusion with al ogeneic bone pad can achieve satisfactory effects, which can be better for intervertebral fusion and cannot induce pain due to bone cutting.

BACKGROUND: For treatment of femoral neck fracture, all therapies with the exception of joint replacement encounter the problems including slow healing, poor prognosis, various complications, and unable to bear weight for long time. Fracture hip supporting joint (FHSJ) is a novel unlimited hip support implement that possesses the double functions of fracture fixation and joint supporting and can be used to prevent and treat the complications of femoral neck fracture in young people.OBJECTIVE: To investigate the mechanical effects of FHSJ on treatment of femoral neck fracture.METHODS: Three types of two-dimensional finite element models were constructed by AutoCAD: normal hip (group A), femoral neck fracture fixed with two screws (group B), and femoral neck fracture fixed with two screws and FHSJ (group C). The grids of two-dimensional four nodal point elements were divided by ANSYS (PLANE82). Under the identical condition, the calculations were performed respectively.RESULTS AND CONCLUSION: The stress peak value of femoral head weight-bearing zone was 1.029 and 1.63 MPa in group A and group B, respectively, and that in the group C was 0.1-0.4 MPa. The stress peak value of the screws was 37.186 and 7.474 MPa in the group B and group C, respectively. These results indicate that FHSJ installation based on fixation of multiple screws could promote the recovery of femoral head and neck, which exhibits promising prospects in treatment of femoral neck fracture in young people.

In this paper, the theory of complex adaptive system (CAS) and its modeling method are introduced. The complex characters of the hospital system is analyzed. The agile manufacturing and cell reconstruction technologies are used to reconstruct the hospital system. Then we set forth a research for simulation of hospital system based on the methodology of Multi-Agent technology and high level architecture (HLA). Finally, a simulation framework based on HLA for hospital system is presented.
Computer Simulation ; Hospital Information Systems ; Humans ; Models, Organizational

Objective:To investigate the clinical effect of percutaneous curved kyphoplasty in the treatment of old osteoporotic vertebral body with endplate fracture.Methods:Clinical data of 58 patients suffering from old osteoporotic vertebral bodies with endplate fractures from January 2018 to January 2020 were analyzed retrospectively. All patients had a single vertebral body fracture and were treated with bilateral injection of bone cement with percutaneous kyphoplasty (PKP). According to the shape of the puncture device, the patients were divided into a curved needle group and a ordinary group. There were 28 cases in the curved needle group, including 7 males and 21 females, aged 60-84 years old, with an average age of 71.8±7.8 years. The distribution of vertebral bodies with fractures: T 11 3 cases, T 12 5 cases, L 1 6 cases, L 2 5 cases, L 3 3 cases, L 4 4 cases, and L 5 2 cases. In the ordinary group, there were 30 cases, 8 males and 22 females, with an average age of 73.2±8.4 years (range, 61-88 years). The vertebral body distribution of fracture: T 11 3 cases, T 12 5 cases, L 1 7 cases, L 2 4 cases, L 3 4 cases, L 4 5 cases, and L 5 2 cases. The surgery time, amount of bone cement injection, and bone cement leakage rate were compared between the two groups, as well as the visual analogue scale (VAS) and Oswestry disability index (ODI) at 1 week, 6 months, and 1 year after surgery. Preoperative and postoperative vertebral midpoint height and kyphosis Cobb angle were measured. Results:All patients were followed up for 12-24 months, with an average of 14.7±2.9 months. The bone cement leakage rate in curved needle group (18%, 5/28) was lower than that in ordinary group (23%, 7/30), but there was no significant statistical difference (χ 2=0.27, P=0.607). The amount of bone cement injection and surgery time in curved needle group (5.0±0.5 ml, 55.2±6.9 min) were significantly higher than those in ordinary group (3.4±0.6 ml, 42.9±3.6 min, P<0.05) . The scores of VAS (2.3±1.0, 2.6±1.5) and ODI (27.5%±9.7%, 28.7%±11.3%) in curved needle group were lower than those in ordinary group (2.7±1.0, 4.5±1.1 and 31.8%±10.5%, 43.1%±13.4%) at 6 months after surgery and at the last follow-up after surgery. In the curved needle group, the Cobb angle was 25.5°±3.5° preoperatively, 18.4°±1.6° postoperatively, and 20.5°±4.9°at the last follow-up. The height of the vertebral body was 14.2±1.9 mm before surgery, 21.5±2.2 mm after surgery, and 20.1±3.6 mm at the last follow-up. Compared with the preoperative results, the kyphosis Cobb angle decreased and the height of the fractured vertebral body increased at the last follow-up, and the differences were statistically significant ( P<0.05). In the ordinary group, the Cobb angle was 24.4°±3.6° preoperatively, 23.1°±4.0° postoperatively, and 27.8°±2.9° at the last follow-up. The height of the vertebral body was 14.5±1.8 mm before surgery, 15.4±2.0 mm after surgery, and 12.7±1.0 mm at the last follow-up. At the last follow-up, the kyphosis Cobb angle increased and the height of the fractured vertebral body decreased compared with preoperative and postoperative 1 week, and the differences were statistically significant ( P<0.05). At 1 week after surgery, 6 months after surgery and the last follow-up, the Cobb angle of curved needle group was lower than that of ordinary group ( P<0.05), the height of vertebral body was higher than that of ordinary group ( P<0.05). Conclusion:Flexible application of percutaneous curved kyphoplasty in the treatment of old osteoporotic vertebral body with endplate fractures can effectively increase the riveting force of bone cement in the vertebral body, restore the height of endplate, and reduce the occurrence of kyphosis and chronic low back pain.