Objective To evaluate the reversion possibility of hVEGF165 and TGF?1 to intervertebral disc degeneration by gene method. Methods The hVEGF165cDNA obtained from plasmid pcDNA3(+)-hVEGF165 was subcloned into the packaging plasmid pSNAV of AAV by molecular clone ways. The recombinant plasmid pSNAV-hVEGF165 was identified by restriction enzymes analysis and sequencing analysis, and then transfered to the HEK293 cell and VEC by lipofectamine mediated gene transfer method. The protein hVEGF165 was detected by immunofluorescence for immunocytochemistry and explored the influence to the proliferation of vascular endothelial cell by MTT. Whereafter the AAV-hVEGF165 was packaged by Benyuan Zhengyang Company. AAV-hVEGF165 and AAV-TGF?1 were cotransfected into annulus fibrosus cell of intervertebral disc, then the expression of hVEGF165 and TGF?1, and the change of collagen Ⅰin annulus fibrosus cell were detected by Western blot. Results The recombinant pSNAV-hVEGF165 was completely constructed and confirmed by restriction enzymes analysis and sequencing analysis. The protein hVEGF165 was detected by immunofluorescence for immunocytochemistry in experimental group, and hVEGF165 could promote the proliferation of vascular endothelial cell. The bioactive AAV-hVEGF165 was successfully constructed. The expression of AAV-hVEGF165 and AAV-TGF?1 were manifested in degenerative annulus fibrosus cell by Western blot, and the expression of collagen Ⅰin annulus fibrosus cell cotransfected by AAV-hVEGF165 and AAV-TGF?1 was markedly more than that of the monogenic transfected cell. Conclusion hVEGF165 could cooperate with TGF?1 to promote the expression of collagen Ⅰ.

Objective Few studies are reported on the construction of a finite element model of human complex knee joint using multimodality CT and MRI images.In this study, we developed a finite element model of the knee joint for total knee arthroplasty (TKA) using matched and fused CT and MRI data, hoping to provide a useful tool for the simulation study of knee joint biomechanics of TKA.Methods The CT and MRI image data about an intact knee of a 26-year-old male volunteer were imported into the Mimics software for the establishment of 3D models of bony and soft-tissue structures.A complete knee model was developed following the registration and fusion of the constructed 3D models based on the external landmarks.After the simulated implantation of TKA components, a finite element model of the TKA knee was constructed with the Hypermesh software.Then the finite element model was analyzed following the definition of its material behavior, boundary conditions and loading.Results The finite element model of the TKA knee, which was composed of bones, ligaments, components, polyethylene insert and bone cement, was developed from CT-MRI image registration and fusion and maintained its important spatial relationship among different structures in the TKA knee.The results obtained from the finite element analysis showed the characteristics of stress distribution in the TKA knee.Conclusion The finite element model of the knee joint for TKA can be established by matching and fusing CT and MRI image data, which can be employed as a useful tool for the study of knee joint biomechanics of TKA.

BACKGROUND:With social progress,the incidence rate of knee osteoarthritis is getting higher and higher in the face of the rapidly developing aging problem in the social population,and the number of total knee replacement operations is gradually increasing. OBJECTIVE:To study the relationship between prosthesis size and stress shielding by improving the tibial prosthesis base. METHODS:A female patient with severe knee osteoarthritis was selected.Based on Mimics,through extracting the bone structure of the knee joint and simulating the total knee replacement surgery,osteotomy,positioning,and implantation operations were carried out to establish the geometric modeling of the total knee replacement prosthesis(including the femoral prosthesis,tibial bracket,and tibial pad),and improve the design of the tibial prosthesis base,analyze the effect of different tibial prosthesis bases on stress shielding of surrounding bone tissue. RESULTS AND CONCLUSION:(1)Compared with single-stem tibial intramedullary stem prosthesis,the design of four-post tibial intramedullary stem prosthesis created a certain degree of stress shielding around the short stem.However,compared with a thicker single long stem,this stress shielding effect was significantly reduced,and the load was evenly distributed among the four short stems,so there was no stress concentration at the bottom of the pile.(2)The design with a rectangular hole in the middle not only provided relatively good stability,but also helped to reduce stress shielding of cancellous bone to a certain extent,with a reduction rate of 77.5%.(3)Compared with a single-stem tibial intramedullary stem prosthesis,both the four-post tibial intramedullary stem prosthesis and the four-post tibial intramedullary stem prosthesis with a hole in the middle have good stability,which can reduce stress shielding to a certain extent without causing stress concentration,providing theoretical guidance for the design of the tibial intramedullary stem.

BACKGROUND:Total knee arthroplasty serves as an effective intervention for the treatment of late-stage knee joint disorders.However,prosthetic liners are prone to wear and failure due to internal stress variations,resulting in limited lifespan and decreased postoperative patient activity.Addressing how to enhance prosthetic design to meet a broader range of patient needs constitutes a significant focus in prosthesis research. OBJECTIVE:Based on the morphological design of the meniscus,we propose an asymmetric design prosthesis and compare it with a symmetric posterior stabilized prosthesis.The stress distribution patterns and variations in the contact area of the liners for both prostheses were analyzed to explore whether the asymmetric prosthesis design offers advantages over the symmetric design. METHODS:Using the finite element method,we simulated the osteotomy and prosthesis assembly in a knee osteoarthritis patient.Two different prostheses(asymmetric design and posterior stabilized)were employed to establish post-total knee arthroplasty knee joint models.Under flexion conditions at 0°,10°,20°,and 30°,we investigated the Mises stress on the femoral and tibial components as well as the liner.Additionally,by comparing the contact area on the inner and outer sides of the liner,we aimed to explore the changes in biomechanics and alterations in motion behavior in the post-total knee arthroplasty knee joint. RESULTS AND CONCLUSION:(1)Throughout the flexion range from 0 to 30 degrees,the Mises stress peak on the liner exhibited a trend of initial decrease followed by an increase,with the stress on the medial side consistently surpassing that on the lateral side.(2)In comparison to the posterior stabilized prosthesis,the asymmetrically designed prosthesis demonstrated smaller stress peaks.At a flexion angle of 30 degrees,the Mises stress peak values of the medial and lateral parts of the asymmetric prosthesis were 15.81 MPa and 11.95 MPa,and those of the posterior stabilization prosthesis were 16.70 MPa and 13.76 MPa.The difference of Mises stress on the medial part was 5.33%,and the difference of Mises stress on the lateral part was 13.15%.Comparing the peak Mises stress on the femoral and tibial components,the asymmetric component was always lower than the posterior stable component during knee flexion.(3)In the upright position at 0 degrees,the medial contact area of the posterior stabilization prosthesis was 17.96 mm2,and the lateral contact area was 34.10 mm2.The contact area on the inner and outer sides of the asymmetric design prosthesis liner was 105.47 mm2 and 107.80 mm2,respectively,indicating a larger contact area with a smaller difference between the inner and outer sides.(4)These results suggest that the biomechanical performance of the asymmetric prosthesis is superior,contributing to the maintenance of knee joint stability and improved joint mobility.This design,to a certain extent,mimics the rotational motion mechanism of the knee joint about the medial condyle as an axis,making it a more effective choice for knee joint prosthesis selection.

Objective:To investigate the relationship between the serum alkaline phosphatase (ALP), prostate specific antigen (PSA) and bone metastasis in initially diagnosed prostate cancer (PCa) patients in different ISUP(International Society of Urological Pathology)groups.Methods:The 368 initial diagnosed prostate cancer patients recruited from January 2013 to December 2018 were retrospectively analyzed, including 247 cases in the Third Affiliated Hospital of Sun Yat-sen University, 111 cases in the Yuebei People's Hospital Affiliated to Medical College of Shantou University and 10 cases in Shenzhen Hospital of Southern Medical University. According to whether there was bone metastasis at the initial diagnosis, it was divided into 230 cases in the bone metastasis group and 138 cases in the non bone metastasis group. There was no significant difference between the two groups in age [(71.9±9.4) years and (71.2±8.7) years], body mass index (BMI) [(23.1±3.7) kg/m 2 and (23.7±2.6) kg/m 2]. There were significant differences in PSA [(307.3±847.0) ng/ml and (84.5±257.3) ng/ml] and ALP [(174.5±270.8) U/L and (71.0±23.2) U/L] between the two groups. In different PSA subgroups, there were 45 cases in PSA <10 ng/ml, 35 cases in PSA 10-20 ng/ml and 288 cases in PSA >20 ng/ml. The differences of ALP and PSA between bone metastasis group and non-bone metastasis group based on different ISUP stratification were analyzed, ROC curves were used to predict their risks of bone metastasis. Results:There were 3(1.3%), 22(9.6%), 34(14.8%), 85(37.0%) and 86 (37.4%) prostate cancer patients with bone metastasis from ISUP group 1 to 5, and 14(10.1%), 19(13.8%), 29(21.0%), 32(23.2%) and 44(31.9%) without bone metastasis, respectively. There was significant difference in the serum ALP levels between the bone metastasis group and the boneless metastasis group in the ISUP group 4(157.6±207.7 vs. 66.5±17.0) and 5(189.4±257.5 vs. 69.2±18.4)( P<0.001) and PSA levels had difference in the ISUP group 3(240.3±313.0 vs. 42.4±42.1), 4(152.3±184.5 vs. 44.7±33.3) and 5(435.2±1006.3 vs. 60.8±84.8)( P<0.001). There was statistically significant between the bone metastasis group and the without(336.1±882.2 vs. 139.3±328.1) when PSA>20 ng/ml( P=0.006). ROC curve analysis: the cut-off values of ALP were 115.5, 109.0, 75.5 and 86.0 U/L from ISUP group 2 to 5 respectively, the sensitivity was 23.8%, 56.5%, 66.4% and 50.6% respectively, the specificity was 99.7%, 93.4%, 78.3% and 89.2% respectively, and the accuracy were 59.4%, 73.1%, 69.7% and 63.3%, respectively. The cut-off values of PSA were 39.5, 93.1, 54.2 and 28.9 ng/ml from ISUP group 2 to 5 respectively, the sensitivity was 64.4%, 68.4%, 87.4% and 88.3% respectively, and the specificity was 79.5%, 90.6%, 63.7% and 61.6% respectively, and the accuracy were 71.6%, 78.1%, 80.1% and 79.2%, respectively. Conclusion:ALP increased significantly in ISUP group ≥4 and PSA in ISUP group ≥3, which related to bone metastasis in patients with initial diagnosed prostate cancer.

Objective:To construct a three-dimensional calcaneal finite element model and study its biomechanical distribution by finite element analysis.Methods:Four large calcaneal specimens were taken from the Department of Human Anatomy of Kangda College of Nanjing Medical University in the second semester of 2021—2022. Micro CT scans were performed to obtain the image data of these specimens, and then the three-dimensional calcaneal model was reconstructed using the Mimics and Geomagic Wrap software. The obtained data were imported into the finite element analysis software to perform the material assignments and mesh delineation to obtain the three-dimensional finite element model. The boundary constraints were set, and loads were applied to the calcaneal model to perform finite element analysis calculations, and the stresses and displacements of the finite element model were extracted.Results:The three-dimensional calcaneal model had a high simulation quality. The morphology and structure were complete and without defects, and the size was consistent with that of the real calcaneus, which restores the original bony morphology and structure. The geometric appearance of the three-dimensional calcaneal model after meshing was vivid and lifelike, and without defect. The reconstructed morphology and structure of the three-dimensional model were the same as those of the three-dimensional reconstruction, the size was the same, and the main structure was clearly visible. The meshes and nodes of each component of the three-dimensional calcaneal model were uniformly distributed, and their numbers were comparable to those of the real heel bone. The maximum stresses of the three-dimensional calcaneal model were in the cortical bone, and the maximum stresses were in the same position. These two positions were the lowest part of the anterior part of heel bones. The maximum displacements in the three-dimensional calcaneal model were all less than 0.10 mm.Conclusions:A high-precision three-dimensional finite element calcaneal model has been constructed, which is of good mechanical validity.