RESUMO
Many studies show that transforming growth factor-β (TGF-β) can suppress tumor by inhibiting proliferation and dedifferentiation of cells and promoting cell apoptosis at early stage.But during the progression of tumor,its tumor-promoting action will be more and more obvious with the variation of TGF-β itself and its signal path.TGF-β signal path inhibitors have anti-tumor activity,but the clinical effects and side effects still need to be observed.
RESUMO
In the present work, NiTi alloy substrates were activated by three different pretreatment processes. 5 X SBF1 and 5 X SBF2 concentrated simulated body fluids were prepared with citric acid buffer reagent, and then calcium phosphate coatings were formed quickly on NiTi alloy surface by accelerated biomimetic synthesis after pretreatment. The microstructure, composition and surface morphology of calcium phosphate coatings were studied. The results indicate that calcium phosphate coatings possess porous and net structure, which are composed of precipitated spherical particles with diameter less than 3 microm. The analysis of XRD shows that the main component of calcium phosphate coatings is hydroxyapatite, whereas the concentrated 5 x SBF simulated body fluid, which is in the absence of Mg2+ and HCO3- crystal growth inhibitors, apparently accelerates the growth rate of hydroxyapatite coatings.