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BACKGROUND:The surgical management to reconstruct the stability in lumbosacral region is very chal enging. There are many techniques to reconstruct the stability of the lumbosacral region, but the internal fixation loosening, fracture and pseudoarthosis are not uncommon. OBJECTIVE:Finite element analysis was used to analyze the stability of two types of reconstruction procedures and the stress of the internal fixation system. METHODS:A 64-slice spiral CT scan was used in a subject from L1 to pelvis. The scan data were imported into the Mimics 15.0 software to generate a three-dimensional surface model. The three-dimensional solid model was established using in the SolidWorks software. The solid geometry model of the L3, 4 pedicle screws combined with single iliac screw fixation and L3,4 pedicle screws combined with dual iliac screws and anterior titanium mesh cage support fixation were constructed by the Solidworks software. Two kinds of reconstruction procedures were simulated. The models were given material properties and analyzed by using the ABAQUS software. RESULTS AND CONCLUSION:(1) The maximum stress was 195.3 MPa in the complete model, 189.5 MPa in single iliac screw model, and 149.2 MPa in dual iliac screw+titanium cage model when constrained the roof of double acetabulum and applied a vertical load of 1 000 N. (2) The axial compression rigidity was 551.572 N/mm in the complete model, 613.87 N/mm in the single iliac screw model and 1 683.50 N/mm in the dual iliac screw+titanium cage model. (3) The bending rigidity of the dual iliac screw+titanium cage model was bigger than other models at 6 directions when applied 7 N?m bending loads. The maximum stress of single iliac screw model was bigger than other models. (4) The results suggest that the dual iliac screw+titanium mesh cage reconstruction can effectively restore the stability of the lumbosacral area. The stress of internal fixation system is smal er and more dispersed. There is obvious stress concentration in the connecting rod and the tail of the single iliac screw. The single iliac screw internal fixation system is easy to fatigue fracture and loosening.
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Objective To investigate the effect of single bundle anatomic reconstruction of the anterior cruciate ligament (ACL) with the hamstring autograft through anteromedial approach. Methods From January 2012 to Jan-uary 2014, 39 patients with ACL tore had been treated with single bundle anatomic ACL reconstruction with the hamstring autograft. In this group, 20 males and 19 females, 16 cases of the left knee and 23 cases of the right knee;including 27 cases of sports injuries, 5 cases of traffic accident injury and 7 cases of fall injury.8 cases were acute injury the others were old injury. 22 cases were had the meniscus injury. All patients were treated with single bundle anatomic ACL reconstruction with the hamstring autograft. The femoral tunnel was establish through the anteromedial approach. The medial meniscus suture was performed in 10 cases, partial resection in 2 cases, lateral meniscus su-ture in 9 cases, partial resection in 1 cases. The hamstring autograft was fixed with the RIGFIX system in the femoral tunnel and the BIOSURE SYNC in the tibia tunnel. The Lysholm score was used to evaluate the recovery of knee function, and the MRI score was used to evaluate the integraty of the grafts. Results All cases were followedup for 15 to 39 months with an average of 21.5 months. All cases had no vascular nerve injury, joint stiffness, infec-tion and other complications. All cases had good stability after 1 year and recover to normal sports after six months and intense sports after half past a year postoperation. The anterior drawer test and the Pivot shift tests were negative in all patients. The Lacheman test wasⅠin 1 patient and others were negative. The mean Lysholm score was (93.85± 4.33) which significantly increased compared with preoperative scores which was (36.84 ± 5.60) after 15 months (P <0.05). The MRI showed good maturity and normal morphology of the ACL autograft, the MRI score was (9.80 ±1.70) after 1 year postoperation. Conclusion The arthroscopic single bundle individual anatomic ACL reconstruction with hamstring autograft through anteromedial approach is effective, simple to perform and gives a graft the same as nor-mal anatomy. The grafts revascularization is good and effectively restore the stability of the knee.
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BACKGROUND:In anoxic environment, invasive ability of tumor cels significantly increased. The increase in above invasive ability is possibly associated with the changes in urokinase or matrix metaloproteinases. Studies on hypoxia and tumor therapy especialy the effect on chemotherapy have made great progress, and found that hypoxia-inducible factor 1 is a key nuclear factor mediating celular hypoxia response, and also an important factor for regulating cel apoptosis during hypoxia. OBJECTIVE:To observe the effects of cyclooxygenase-2 inhibitor NS-398 on invasive ability of MG-63 cels under hypoxic condition in cel models of hypoxia osteosarcoma. METHODS: Chemical hypoxia inducer cobalt chloride was used to establish chemical hypoxia environment of concentration gradient of 0, 100, 200, 400 μmol/L. Under 200 μmol/L cobalt chloride, concentration gradient of 30, 60, 90 μmol/L of NS-398 were set. Osteosarcoma cels were determined after 48 hours of culture. Quantitative PCR was used to detect the expression of matrix metaloproteinases 9 mRNA and hypoxia-inducible factor 1α mRNA. Western blot assay was applied to measure hypoxia-inducible factor 1α expression. Flow cytometry was utilized to examine cel apoptosis in each group. RESULTS AND CONCLUSION:PCR and western blot assay results demonstrated that with increased concentration of cobalt chloride, matrix metaloproteinases 9 mRNA and hypoxia-inducible factor 1α mRNA and protein expression increased (P < 0.05), showing a concentration-dependent manner. Under cobalt chloride concentration of 200 μmol/L and hypoxia, with increased concentration of NS-398, matrix metaloproteinases 9 mRNA and hypoxia-inducible factor 1α mRNA and protein expression gradualy reduced, showing a concentration-dependent manner (P < 0.05). Flow cytometry results showed that under 400 μmol/L cobalt chloride concentration, cel apoptosis noticeably reduced. Under cobalt chloride concentration of 200 μmol/L and hypoxia, with increased concentration of NS-398, cel apoptosis increased (P < 0.05). Results confirm that anaerobic environment is an important factor for increased invasive ability of osteosarcoma. Under the anaerobic environment, NS-398 could effectively suppress the invasive ability of osteosarcoma and promote cel apoptosis.
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Objective To investigate the change of levels of related cytokines,including transforming growth factor-β2 (TGF-β2),basic fibroblast growth factor (bFGF),platelet-derived growth factor (PDGF),interleukin-6 (IL-6),interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) and behavior in streptozotocin-induced diabetic rats between the before and after fracture,at the same time,to analyse the relativity of them.Methods The rat models of diabetic were induced by intraperitoneal injection of streptozotocin,which were divided into different diabetes mellitus group (DM group) randomly.The right tibiofibula of all the rats of diabetes mellitus group and normal control group(NC group) were broken,and then treated with external fixation.The bone callus formation was evaluated by X-ray.When all the operation above was completed,the rats were domesticated in different cages.The concentration of related cytokines of the DM groups and NC group was detected at different time.Results The behavior changes of diabetes fracture rats were distinct and appeared a series symptoms such as bradykinesia,dull,polydipsia,polyphage,polyuria,emaciated obviously.The concentration of related cytokines (TGFβ2,BFGF,PDGF,IL-6,IL-8 and TNF-α) of the two groups was detected at 1,2 and 4 weeks.The difference between them was significantly(TNF-α:the concentration of NC group were (9.87 ± 1.06) ng/ml,(14.07 ± 1.43)ng/ml and(12.02 ± 1.02) ng/ml; the concentration of DM group were (11.65 ± 1.18) ng/ml,(16.29 ± 1.24)ng/ml and(13.87 ± 1.25)ng/ml ; P ＜ 0.05).X-ray films showed that the fracture healing of NC group was more superior than that of DM group.Conclusion The reduction of TGF-β2,BFGF,PDGF and the increase of IL-6,IL-8,TNF-α in early fracture are one of important reasons for delayed union and nonunion in diabetic rats.At the same time,there is a cooperative action between them.Dynamic observation of the concentration of related cytokines will provide eliable experimental data to estimate fracture healing,delayed union and nonunion.It is favourable to acquaint the regulatory mechanism of fracture healing at molecular level.
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BACKGROUND: Myelination following axonal regeneration is a key factor affecting the recovery of spinal cord injury. Oligodendrocyte survival directly affects the myelination following axonal regeneration. OBJECTIVE: To investigate the feasibility of differentiation of rat bone marrow mesenchymal stem cells (BMSCs) into oligodendrocytes induced by neurotrophic factors. DESIGN, TIME AND SETTING: The cell molecular biology in vitro study was performed at the Laboratory of Department of Orthopaedics, Tongji Hospital from September 2006 to June 2007. MATERIALS: A total of 5 Sprague Dawley rats aged 2-4 weeks, of both gender were selected. Bilateral femur and tibia bone marrow was obtained to harvest BMSCs. METHODS: At passage 4, BMSCs were incubated in serum-free medium, supplemented with N2, 20 ng/mL basic fibroblast growth factor, 20 ng/mL epidermal growth factor for 48 hours, and incubated in medium containing 500 ng/mL insulin-like growth factor I and N2 for 3 days. MAIN OUTCOME MEASURES: Morphological changes were observed using an phase contrast microscope. Semiquantitative RT-PCR was utilized to detect specific marker mRNA expression of oligodendrocytes. Using neuron marker anti-microtubule-associated protein, astrocyte marker anti-glial fibrillary acidic protein, oligodendrocyte marker anti-galactocerebroside, anti-myelin basic protein antibody, immunocytochemical staining was performed to detect the positive rate of the differentiation of BMSCs into oligodendrocytes. RESULTS: Morphological changes in BMSCs during the differentiation into oligodendrocytes: After the induction, a majority of BMSCs presented the morphological characteristics of oligodendrocytes. Cytoplasm retraction towards nucleus, cell process extension towards outwards, and strong refraction were found. With the prolongation of time, several cell processes connected and formed a typical net-shape structure. Specific marker mRNA expression of oligodendrocytes: Following induction, specific strap of myelin basic protein mRNA and galactocerebroside mRNA could be detected. Positive rate of oligodendrocytes: During induction, the positive rates of galactocarebroside, myelin basic protein and microtubule-associated protein were 65%, 45% and 10%, respectively. CONCLUSION: The combination of epidermal growth factor, basic fibroblast growth factor and insulin-like growth factor can effectively promote the directional differentiation of BMSCs into oligodendrocytes.
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Objective To investigate the repairing effect of transplantation of allogeneic fetal bone in combination with a covering cryopreserved periosteal allograft to bone defect. Methods Twenty Long-eared white male rabbits were chosen as experimental model of bilateral 12 mm combined bony and periosteal radial defect. Cryopreserved allograft periosteum with allogeneic fetal bone were implanted in the left defect as experimental side and fetal bone was simply transplanted in the right defect as control side. Bone repair process in the two groups were compared by macroscopy, microscopy, roentgenograms and the contents of calcium and phosphate in the defect area at 2、4、8 and 12 weeks after transplantation. Results There was significant statistic difference in the contents of calcium and phosphate between the experimental and control sides at 4、8 and 12 weeks after transplantation (P<0.05). With time passing by, the contents of calcium and phosphate have the increasing trends. In the experimental group, lamella bone was seen and medullary canal recanalized at 8 weeks postoperatively. The histological section showed the bone lacuna and lamella bone were formed. Conclusion It suggests that allogeneic fetal bone in combination with a covering cryopreserved periosteal allograft can promote bone repair, and allogeneic fetal bone is excellent bone substitute.