Effects of alloying elements on the cytotoxic response of titanium alloys

Titanium alloys, alloys, especially beta-type alloys containing beta-stabilizing elements, constitute a highly versatile category of metallic materials that have been under constant development for application in orthopedics and dentistry. This type of alloy generally presents a high mechanical strength-to-weight ratio, excellent corrosion resistance and low elastic modulus. The purpose of this study is to evaluate the cytotoxicity and adhesion of fibroblast cells on titanium alloy substrates containing Nb, Ta, Zr, Cu, Sn and Mo alloying elements. Cells cultured on polystyrene were used as controls. In vitro results with Vero cells demonstrated that the tested materials, except Cu-based alloy, presented high viability in short-term testing. Adhesion of cells cultured on disks showed no differences between the materials and reference except for the Ti-Cu alloy, which showed reduced adhesion attributed to poor metabolic activity. Titanium alloys with the addition of Nb, Ta, Zr, Sn and Mo elements show a promising potential for biomedical applications. (C) 2011 Elsevier B.V. All rights reserved.

Genomic organization and transcription analysis of the 195-bp satellite DNA in Trypanosoma cruzi

The 195-bp satellite DNA is the most abundant Trypanosoma cruzi repetitive sequence. Here we show by RNA blotting and RT-PCR that 195 SAT is intensely transcribed. We observed a positive correlation between the level of satellite RNA and the abundance of the satellite copies in the genome of T cruzi strains and that the satellite expression is not developmentally regulated. By analyzing CL Brener individual reads, we estimated that 195 SAT corresponds to approximately 5% of the CL Brener genome. 195 SAT elements were found in only 37 annotated contigs, indicating that a large number of satellite copies were not incorporated into the assembled data. The assembled satellite units are distributed in non-syntenic regions with Trypanosoma brucei and Leishmania major genomes, enriched with surface proteins, retroelements, RHS and hypothetical proteins. Satellite repeats were not observed in annotated subtelomeric regions. We report that 12 satellite sequences are truncated by the retroelement VIPER. (C) 2008 Elsevier B.V. All rights reserved.