BACKGROUND: Histomorphological change of endplate may affect the nntritional transmission of intervertebral disk, eventually leading to intervertebral disc degeneration. OBJECTIVE: To observe the effects of endplate concavity variation on mechanical response of lumbar motion segment. DESIGN, TIME AND SETTING: Repeated measurement design, biomechanical analysis of finite element models, performed at the Laboratory of Biomechanics, Department of Orthopedics, the Second Affiliated Hospital of Medical College of Zhejiang University between January 2005 and January 2007. MATERIALS: SOMATOM SENSATION 16 spiral CT machine (Siemens, German) and ANSYS (Inc. Pennsylvania, USA).METHODS: A three-dimensional nonlinear geometrical and mechanical accurate finite element model of lumbar L<,4-5> segment was developed. Parametric studies were undertaken by studying endplate of three different concave angles, whereas disc angle, the gap of facet joint, finite element mesh density, and all other parameters were kept constant. Biomechanical parameters of three kinds of finite element models were tested under 5 different loading conditions, including vertical compression, flexion, extension, and anterior and posterior shearing loading. MAIN OUTCOME MEASURES: Endplate-intervertebral disc interface strain, intervertebral disc stiffness, nucleus pulposus pressure, annular fiber stress, radial disc bulge, stress in the annulus ground substance, stresses in posterior structure and facet contact force. RESULTS: The decrease in the endplate concavity stimulated by an increasing endplate concave angle would result in decreased strains of endplate-intervertebral disc interface, increased disc stiffness and nucleus pulposus pressure, decreased annular fiber stress, radial disc bulge and stress in the annulus ground substance, and simultaneously produce decreased facet contact force and stresses in posterior structure. CONCLUSION: The decrease of endplate concavity enhances the protective effects of the disc on vertebral body breakage. Small endplate deformation results from decreased endplate concavity would contribute to the reduction of nutritional diffusion to the intervertebral disc.

[Objective] The efleet of sagittal orientations of articular facet on the contact force and contact regions of a lumbar spine segment was evaluated.[Methods] [Results]Three-dimensional geometrical and mechanical accurate finite element models of the lumbar L4、5 motion segment representing three sagittal-orientations articular facet were generated and invalidated by an effective CAD method.Contact force and contact regions of the articular facets of three finite element models were predicted under the pure shearing loads.[Result] Under anterior shear condition,the contact force on the facet decreased with the increase of sagittal 0rientation of articular facet.however.in posterior shear load,the contact force on the facet increased with the increase of sagittal orientation.Meanwhile,under both pure shear loading,the percentages of the sagittal and the transversal components are increased with the dectease of the sagittal angle.However,under the salne load condition,there are no difference between the contact regions of the three models with different facet joint angle.[Conclusion]The spatial orientation and geometric forms of the coronal facet articular surfaces are more effective in restricting motion in transversal and sagittal planes while assuming a minor role in resisting axial force or motion than sagittal facet articular surface.It Was presumed that anterior shear force play a more prominent contribution on the degeneration of the facet joint with coronal articular surface compared with posterior shear force.

Objective To demonstrate the histopathological changes of sequestration-type herniated disc, and investigate the related factors of its absorption. Methods 39 tissue samples were surgically removed from 37 patients with sequestration-type lumbar disc herniation. All the tissues were performed with HE stain and immunohistochemical study. In HE stain, the origin of tissue was identified; in immunohistochemical study, anti-CD34 antibody was used for detecting the vascular endothelial cells, and anti-CD68 for macrophages. The sequestration-type lumbar disc was divided into 3 groups according to the content of nucleus pulposus: nucleus pulposus group, nucleus pulposus contained group and non-nucleus pulposus group. The correlation between the extent of angiogenesis and macrophage infiltration and the factor of age, disease duration, origin of sequestrated tissue and imaging features was studied. Results 62% (24/39) of the sequestrated tissues were mainly originated from nucleus pulposus. Granulation tissue with many macrophages around new blood vessels was found in 92%(36/39) of the sequestrated tissues. There was a significant difference of the extent of angiogenesis and macrophage infiltration among these 3 groups in terms of the content of nucleus pulposus group(F=5.663, P=0.008; F=3.604, P=0.038). There was no significant correlation between the extent of angiogenesis and macrophage infiltration and age or disease duration, whereas, a positive significant correlation was found for the size of sequestrated tissue (r=0.342, P=0.033; r=0.440, P=0.005). Furthermore, the extent of angiogenesis and macrophage infiltration was significant when the relative signal intensity of sequestrated tissue on MRI was in 0.30-0.72. Conclusion The origin of sequestration-type herniated disc is mainly from nucleus pulposus, and most of the sequestration tissue can be absorbed in different extent. The extent of spontaneous absorption was mainly depended on the origin of the sequestration tissue, but not the age or disease duration. Predominant absorption is found in bigger size of the sequestration tissue and their relative signal intensity on MRI being 0.30-0.72.

Objective To research the connection between the sagittal orientation of facet joints and disc degeneration in lumbar spine and to investigate the contribution of which to development the degenerative spondylolisthesis. Methods A new effective CAD method was used to accurately establish 9 finite element models(FEM)which were assembled respectively with facet-joint angle 65?, 45?, 25?, with normal disc, light degenerative disc and severe degenerative disc. The biomechanical parameters of 9 finite element models were measured under axial compressive load within physiological range. Results Compared with FEMs with facet-joint angle 45? and 25?, anterior displacement of L4 vertebra in FEMs with facet-joint angle 65? was increased, where the maximum von Mises stresses on facet surface, isthmus and the contact force on facet surface in horizontal orientation were obviously increased. Meanwhile, FEMs with facet-joint angle 65? showed a decrease in end-plate bulge and an increase in stress of annular matrix. The stiffness in light degenerative disc FEMs was reduced and the von Mises stresses on facet surface and isthmus was slightly increased compared with the normal disc FEMs. Among all, the FEM with facet-joint angle 65? combined with light degenerative disc showed the poorest resisting anterior shear force. Conclusion Sagittal orientation of facet joints is not only the primary inducement of the degenerative spondylolisthesis but the secondary pathological change of remodeling of the facet-joints induced by the regional stress change. The inherent instability of lumbar motion segment of sagittal orientation of facet joints is influenced by the lumbar disc degeneration. The lumbar disc degeneration has no manifested contribution to the aggravation of the sagittal orientation of facet joints.

AIM:To investigate the inhibitory effect of aliskiren on the angiogenesis of human umbilical vein endothelial cells ( HUVECs) induced by lipopolysaccharide ( LPS) and to explore its possible mechanism.METHODS:HUVECs were cultured and randomly divided into blank group and renin group.The levels of tumor necrosis factor-α(TNF-α) and intercellular adhesion molecule-1 (ICAM-1) in the culture supernatant were detected by ELISA.The protein levels of Toll-like receptor 4 ( TLR4) and ICAM-1 in the HUVECs were determined by Western blot.HUVECs were cul-tured and randomly divided into control group, LPS group, low-dose (1μmol/L) aliskiren group, middle-dose (10μmol/L) aliskiren group and high-dose (100 μmol/L) aliskiren group.The proliferation of HUVECs was detected by MTT and BrdU assays.The mobility of HUVECs was measured by Transwell assay.The formation of the vessels was judged by ob-serving the formation of the luminal structure by HUVECs in Matrigel.The levels of TNF-α, ICAM-1 and monocyte chemo-tactic protein 1 ( MCP-1) in the culture supernatant were measured by ELISA.The expression of renin, TLR4, matrix me-talloproteinases-2 (MMP-2) and matrix metalloproteinases-9 (MMP-9) at mRNA and protein levels in the HUVECs was determined by RT-PCR and Western blot.RESULTS:Renin stimulated the expression of inflammatory factors and TLR4 in the HUVECs.Aliskiren inhibited the growth, migration and angiogenesis of HUVECs in a dose-dependent manner, de-creased the levels of TNF-α, ICAM-1 and MCP-1 and the expression of renin, MMP-2 and MMP-9, and inhibited TLR4 expression (P<0.05).CONCLUSION:Aliskiren inhibits LPS-induced angiogenesis of HUVECs, which may be related to the down-regulation of renin expression, the inhibition of TLR4-mediated inflammatory reaction, and the formation of MMP-9 and MMP-2.

Based on the investigation of the rehabilitation demand of disabled persons and the functional advantage of existing health care and services network in Heilongjiang provincial reclamation area, a structural design of community-based rehabilitation development has been drawn out, which including integrating existing three-level health care network, applying appropriate rehabilitation techniques, to establish a convenient, effective, and economical community-based rehabilitation system.

BACKGROUND: How to deal with bone defect is a big problem to surgeons. In recent years, the development in the technology of molecular biology and tissue engineering provides broad prospect for the clinical treatment of bone defect, which is one of the important study directions in department of orthopedics. The transforming growth factor-beta 1(TGF-β1),one of the important factors in bone formation, plays an important role in bone metabolism and recovery.OBJECTIVE: To observe the therapeutic effects of bone defects with osteoblasts transfected . By TGF-β1 combining with biomimetic biodegradable polymer scaffolds.DESIGN: Randomized controlled trial.SETTING: Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.MATERIALS: Siderophilin, trypsin, 3H-proline and sirius red, etc.MATERIALS: The experiment was completed in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from March to August in 2003. Twenty healthy adult Sprague-Dawley(SD) rats of SPF grade, weighing 200-250 g, were provided by the Experimental Animal Center of Tongji Medical College.METHODS: The osteoblasts transfected by TGF-β1 gene, combining with poly-DL-lactic acid scaffolds modified with poly-L-lysine, were transplanted into rat tibia defect. Radiographs and histological analysis were performed to evaluate the repair effects.MAIN OUTCOME MEASURES: The X-ray evaluation and histology observation were performed at the 4th and 8th weeks after the operation.RESULTS: Totally 20 SD rats were included in result analysis without one rat missing. ①In the experiment group, X-ray image indicated callus formation, while histology observation showed osteoid tissue and new bone formation, and osteoblasts attached to the surface of the materials after 4 weeks. Eight weeks later, the defect was essentially repaired, and the bone density of new bone was similar to that of the autogenous bone. ②In the control group, there was no formation of callus and osteoid tissue, and few osteoblasts attached to the surface of the materials, and a lot of lymphocytes infiltrated and blood capillary grew in the lacune of materials after 4 weeks. Eight weeks later, the imbedded materials were substituted mostly by fibrous tissue.CONCLUSION: The ideal repair effect of bone defect can be obtained through the combination of molecular biology with tissue engineering.

The necessity and superiority of the surgical operation on children with floating knee injury and the fracture union and complications were investigated. Twenty-eight children with floating knee injury were subjected to open reduction and internal fixation or external fixator. The patients were followed up for 18 months to 7 years. The curative effectiveness was scored by Karlstrom criteria. The results showed that no nonunion or deformity was found. The affected limb was 1.2 cm to 1.5 cm longer in 2 cases, 0.8 to 1.2 cm shorter in 3 cases than the contralateral. No severe dysfunction of knee joint occurred. The excellent-good rate was 92.8% and the curative rate 71.4% respectively. So for children whose age is older than 5 years, it's a good way to treat the fractures of femur and tibia with open reduction and internal fixation or external fixator. The method can be advantageous for the nursing care, early function recovery, shortening of the hospital stay and avoidance of severe complications.
Femoral Fractures/complications ; Femoral Fractures/*surgery ; Fracture Fixation ; Knee Injuries/classification ; Knee Injuries/etiology ; Knee Injuries/*surgery ; Tibial Fractures/complications ; Tibial Fractures/*surgery ; Treatment Outcome

Objective To optimize the antibacterial drug regimen in ICU common staphylococcal infection.Methods The pharmacokinetic and pharmacodynamic parameters of antibacterial drugs were collected in combination with the hospital ICU anti-microbial drug resistance monitoring reports from the national antimicrobial resistance investigation net (Mohnarin)of the Ministry of Health and the performance standards for antimicrobial susceptibility testing (2013)issued by the clinical and laboratory stand-ards institute (CLSI),the minimum inhibitory concentration (MIC)of staphylococci was set by using the discrete uniform distribu-tion method and 16 kinds of administration regimens with 6 antimicrobial agents were worked out.The best initially antimicrobial regimen was optimized by using the pharmacokinetic and pharmacodynamic models and Monte Carlo simulations of cumulative frac-tion of response (CFR)from 5 000 patients.Results The alternative initially drug regimens to the infectious bacteria were:linezolid 0.40 g twice daily and vancomycin 0.75 g twice daily for staphylococcus aureus;amikacin 0.60 g once daily and linezolid 0.40 g twice daily,and vancomycin 0.75 g twice daily for hemolytic staphylococci and staphylococcus epidermidis;linezolid 0.40 g twice daily and vancomycin 0.75 g twice daily for methicillin-resistant Staphylococcus aureus;ampicillin/sulbactam 1.50 g 4 times daily, cefuroxime 0.75 g 4 times daily,amikacin 0.60 g once daily,moxifloxacin 0.40 g once daily for methicillin-sensitive staphylococcus aureus.Conclusion In the Staphylococcus aureus infection occurred in ICU,if which being methicillin-sensitive could be deter-mined,ampicillin/sulbactam,cefuroxime,amikacin and moxifloxacin could be selected for treatment,and linezolid or vancomycin could be selected for treating possible methicillin-resistant Staphylococcus aureus infection or undetermined whether being methicil-lin-resistant Staphylococcus aureus infection.