ABSTRACT
The surface characteristics of titanium have been shown to have an important role in contact ossseointegration around the implant. Anodizing at high voltage produces microporous structure and increases thickness of surface titanium dioxide layer. The aim of present study was to analyse the response of rat calvarial osteoblast cell to commercially pure titanium and Ti-6Al-4V anodized in 0.06 mol/l beta-glycerophosphate and 0.03 mol/l sodium acetate. In this study, rat calvarial osteoblasts were used to assay for cell viability and cell proliferation on the implant surface at 1, 2, 4, 7 days. 1. Surface roughness was 1.256micrometer at 200V, and 1.745micrometer at 300V. 2. The thickness of titanium oxide layer was increased 1micrometer with the increase of 50V. 3. The proliferation rate of osteoblastic cells was increased with the increase of the surface roughness and the thickness of titanium oxide layer. 4. There was no difference in cell viability and cell proliferation between commercially pure titanium and Ti- 6Al-4V anodized at the same condition. In conclusion, the titanium surface modified by anodizing was biocompatible, produced enhanced osteoblastic response. The reasons of enhanced osteoblast response might be due to reduced metal ion release by thickened and stabilized titanium dioxide layer and microporous rough structures.
Subject(s)
Rats , AnimalsABSTRACT
BACKGROUND: Mycobacteria are traditionally identified with biochemical reactions. Since it takes 2 to 6 weeks, more rapid method is needed for timely treatment of mycobacterial infection. Mycolic acid analysis by high-performance liquid chromatography (HPLC) was recently introduced, which showed species-specificity with more than 95% sensitivity and 100% specificity for identifing Mycobacterium spp. within 2-4 hours. In this study, We performed mycolic acid analyses of standard strains of Mycobacterium spp. and two clinical isolates of known M. tuberculosis for demonstrating their species-specific nature and evaluated its reproduciblity. METHODS : 8 standard strains of Mycobacterium spp. (M. tuberculosis H37Rv, M. intracellurae, M. avium, M. fortuitum, M. chelonae subsp. chelonae, M. scrofulaceum, M. kansasii, M. gordonae) and 2 clinical isolates of known M. tuberculosis were analyzed. The extracted mycolic acids which were prepared by 3 steps were analyzed by HPLC with rC18 column. RESULTS: Mean retention time (MRT) of low and high molecular weight internal standards were 3.757min+/-0.017 (C.V. <0.455%) and 9.829min+/-0.015 (C.V. <0.015%), respectively (n=30). The C.V. of MRT for M. intracellurae for positive control showing double cluster pattern was less than 0.3% from 4 injection. The C.V. of MRT for M. tuberculosis H37Rv and 2 clinical isolates of M. tuberculosis with single cluster pattern were less than 0.4%, and 0.9%, respectively. The chromatographic patterns of M. kansasii and M. gordonae showed a single cluster pattern, and M. avium, M. fortuitum, M. chelonae subsp. chelonae, and M. scrofulaceum showed a double cluster pattern which were species-specific nature. CONCLUSIONS: We demonstrated HPLC method was rapid and highly reproducible.