In Vitro Characterizations of PLLA/β-TCP Porous Matrix Materials and RMSC-PLLA-β-TCP Composite Scaffolds

To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissueengineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, i.e. solventcasting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behaviorof the porous scaffold, e.g. weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP,the particle size of β-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporatedinto the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold weredetermined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Resultsshow that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strengthneeded for surgery. RMSCs seeding on porous PLLA/β-TCP composite behaves good seeding efficacy, biocompatibility andosteoinductive potential. Osteoprogenitor cells could well penetrate into the material matrix and begin cell proliferation andosteogenic differentiation. Osseous matrix could be formed on the surface of the composite after culturing in vitro. It isexpected that the PLLA/β-TCP porous composites are promising scaffolds for bone tissue engineering in prosthesis surgery.

Osteogenesis and Degradation Behavior of rhBMP-2／β-Tricalcium Phosphate Porous Composite Materials

Ultrafine-tricalcium phosphate(β-TCP)powders with good crystalline structure were produced by a new process through bone tissue engineering approach rorous β-TCPcermic was combined with recombined human bone morphogenetic proteins-2(rhBMP-2)to develop a novel composite material ,osteogenesis capacity of the composite was investigated intramuscularly in rat with histological analyses and SEM examination pureβ-TCP porous carmic wsa investigated as the control results show that the compostie materials possess good bilcompatibility biodegradation and strong osteogenesis capacity through inductive process after implantation material degradation began from 2 weeks post-implantation accompanying with the changing o pore structure with the enwrapping and separation fo materials by hyperplatic mesenchymal cells and fibroblast and with the phagocytose reaction of multinucleated giant cells early in 72h immature cartilage could be found within novel composite mature lamellar bone was induced to generate after 3 weeks with strong osteoinduction capacity and controlable bildegradation the novel rhBMP-2\β-TCP porous ceramic is expected to be a promising bone grafting substitute for bone tissue engineering

Liver fibrosis caused by choledocholith to regress after biliary drainage

AIM: To study the correlation between liver fibrosis severity and biliary drainage in patients with choledocholith.METHODS: A follow-up study on seven patients with liver fibrosis due to choledocholith was made. The data, including biochemical tests (aspartate aminotransferase, alanine aminotransferase) and liver histological features before and after biliary drainage, were collected and studied. The fibrosis severity was scored on a scale from 0 to 3, with 0 denoting none, 1 portal and periportal fibrosis, 2 the presence of numerous fiber septa, and 3 cirrhosis. The average liver fibrosis severity scores of the first and second biopsy were compared with statistical method.RESULTS: The first, second liver fibrosis severity scores of these seven patients were 2,1; 2,1; 1,0; 1,1; 2,1; 2,1;1,0 respectively. The results showed that the average liver fibrosis severity score of the second liver biopsy decreased significantly compared with the first liver biopsy (n = 7, t = 4.25, P＜0.05).CONCLUSION: Liver fibrosis due to choledocholith may regress after biliary drainage.