Bioinformatics Analysis on Key Genes and Immune Infiltration of Osteosarcoma / 中国医学科学院学报

Objective To screen the potential key genes of osteosarcoma by bioinformatics methods and analyze their immune infiltration patterns. Methods The gene expression profiles GSE16088 and GSE12865 associated with osteosarcoma were obtained from the Gene Expression Omnibus(GEO),and the differentially expressed genes(DEGs)related to osteosarcoma were screened by bioinformatics tools.Gene Ontology(GO)annotation,Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment,and analysis of immune cell infiltration were then carried out for the DEGs.The potential Hub genes of osteosarcoma were identified by protein-protein interaction network,and the expression of Hub genes in osteosarcoma and normal tissue samples was verified via the Cancer Genome Atlas(TCGA). Results A total of 108 DEGs were screened out.GO annotation and KEGG pathway enrichment revealed that the DEGs were mainly involved in integrin binding,extracellular matrix (ECM) structural components,ECM receptor interactions,and phosphatidylinositol 3-kinase/protein kinase B(PI3K/Akt)signaling pathway.Macrophages were the predominant infiltrating immune cells in osteosarcoma.Secreted phosphoprotein 1(SPP1),matrix metallopeptidase 2(MMP2),lysyl oxidase(LOX),collagen type V alpha(II)chain(COL5A2),and melanoma cell adhesion molecule(MCAM)presented differential expression between osteosarcoma and normal tissue samples(all P<0.05). Conclusions SPP1,MMP2,LOX,COL5A2,and MCAM are all up-regulated in osteosarcoma,which may serve as potential biomarkers of osteosarcoma.Macrophages are the key infiltrating immune cells in osteosarcoma,which may provide new perspectives for the treatment of osteosarcoma.

Biomechanical characteristics of hip prosthesis in hip arthroplasty treating elderly patients with Evans I-III intertrochanteric fracture of femur / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the feasibility of hip arthroplasty in the treatment of elderly patients with Evans I-III intertrochanteric fracture of femur by analyzing its biomechanics characters.</p><p><b>METHODS</b>We solved the CT digital image files with the graphics processing software Mimics at DICOM 3.0 standard, and reconstructed the three-dimensional entity of femur with CAD modeling software Unigraphics. Then the fracture line was defined in the model as the line between the tip of greater trochanter and inferior margin of small trochanter, above which the upper bone was removed. Afterwards the two prosthesises with different stem lengths (120 mm and 170 mm) were implanted into the fracture model respectively as hip arthroplasty with 3 mm bone cement layer between prosthesis and femur, and the bone defect was repatched with 5 mm bone cement layer. A three-dimensional finite element model was established with finite element analysis software ABAQUS 6.5. We formulated different material parameters under the stress condition standing with single leg to build the stress distribution map of the femur prosthesis, and took 5 loci of region of stress concentration to calculate the mean value of stress.</p><p><b>RESULTS</b>The stress distribution maps of the short and long stem length prothesises were similar. And there were two areas of stress concentration, including the upper portion and the lower portion close to the joint of the prosthesis stem, and the stress concentration in the junction part was obviously between the lower portion and the upper area of the small trachanter. The stress reached the first concentration area at the junction and then gradually reached the second concentration area at the interior terminal of the stem. While the stress gradually increased along the lateral prosthesis stem, and reached the stress concentration area at the end.</p><p><b>CONCLUSIONS</b>The stress distribution maps in the femur prosthesises are similar between hip arthroplasty in the treatment of intertrochanteric fracture of femur and the traditional hip arthroplasty surgery. The peak stress values are higher in the long stem prosthesis in the treatment of intertrochanteric fracture of femur than the short type, while they are under the rupture value of the metal.</p>