ABSTRACT
Objective To study the effect of different materials and porosities on bone formation in the scaffold after implantation of the degradable bone scaffold into human body. Methods According to natural reaction mechanism of fracture healing, the finite element method was used, combined with geometry of the scaffold, to establish a computationally coupled model based on material degradation curve and bone reconstruction control equation. Through this platform, representative volume elements of the scaffold with five kinds of materials and four types of porosities were selected for calculation and analysis, and dynamic process was reflected by bone mineral density (BMD) and maximum stress of the scaffold. Results The elastic modulus of the materials had a greater influence on growth of bone tissues in the scaffold. The smaller elastic modulus of the materials would lead to the greater amount of bone formation, but it would also have a greater impact on mechanical properties of the scaffold. The scaffold with higher porosity had lower rigidity, which could better promote formation of bone tissues, meanwhile it would also destroy mechanical stability of the scaffold. Conclusions According to performance requirements for different age, gender and location of bone tissues, personalized reference and calculation basis for selection of materials and porosity, structural design and clinical application of degradable porous bone scaffolds can be provided.
ABSTRACT
Objective To investigate the expression of vascular endothelial factor C(VEGF-C) and E-cadherin in gastric cancer and explore the relationship between expression of VEGF-C and E-cadherin and the pathogenesis of gastric cancer.Methods Real-time quantitative reverse ranscriptase-polymerase chain rection was applied on 40 cases of gastric cancer and corresponding adjacent noncancerous tissues,in order to detect mRNA expression of VEGF-C and E-cadherin gene.VEGF-C and E-cadherin protein expression in gastric cancer and adjacent normal gastric mucosa were detected by immunohistochemistry.Statistical analysis was carried out to analyze the correlation among VEGF-C,E-cadherin and protein expression with various clinical parameters in these gastric cancer patients.Results The expression of VEGF-C protein in 40 cases of gastric cancer's cancer tissues was 0.461±0.012,significantly higher than that in the adjacent normal tissues(0.036+0.023;t=1.101,P＜0.05),but E-cadherin expression was significantly lower than that of the adjacent normal tissues (0.079±0.002 vs.0.321±0.005;t=1.844,P＜0.05).There was correlation between VEGF-C mRNA expression with histological grading,TNM staging,lymph node and distant metastasis (t=-1.621,-1.474,-2.378,-1.966,P＜0.05).There was correlation between E-cadherin mRNA expression with tumor size,histological grading,TNM stage,there was a significant difference (t=1.875,1.673,1.544,P＜0.05).VEGF-C and E-cadherin protein expression was negatively correlated(r=-0.688,P＜0.05).Conclusion Up-regulated of VEGF-C gene and decreased expression of E-cadherin may play an important role in the carcinogenesis of gastric cancer