Functional polymorphisms in the promoter of the matrix metalloproteinase-9 (MMP-9) gene are not linked with significant plasma MMP-9 variations in healthy subjects

Background: Matrix metalloproteinase-9 (MMP-9) is involved in the degradation of the extracellular matrix during physiological and pathological processes. Two functional polymorphisms [C(-1562)T and microsatellite (CA)(13-25)] in the promoter region of the MMP-9 gene have been associated with several diseases. The aim of this study was to examine whether these MMP-9 polymorphisms and haplotypes are linked with plasma MMP-9 variations in healthy subjects. Methods: We studied 177 healthy male white volunteers (age range 20-55 years) who were non-smokers and not taking any medication. Genomic DNA was extracted from whole blood and genotypes for the C(-1562)T and the microsatellite (CA)(n) polymorphisms were determined. MMP-9 levels were measured in plasma samples by gelatin zymography. Results: The frequency of the alleles C and T for the C(-1562)T polymorphism were 90% and 10%, respectively. The frequency of the alleles with less than 21 CA repeats Q and with 21 repeats or higher (H) were 47% and 53%, respectively. We found no differences in plasma MMP-9 levels among the genotype groups or among different haplotypes (all p > 0.05). Conclusions: These findings suggest that functional polymorphisms in the promoter of the MMP-9 gene are not linked with significant plasma MMP-9 variations in healthy subjects.

Determination of para-Chloroaniline and Reactive Oxygen Species in Chlorhexidine and Chlorhexidine Associated with Calcium Hydroxide

The aim of this study was to determine whether para-chloroaniline (PCA) and/or reactive oxygen species (ROS) are generated by chlorhexidine (CHX) alone or after CHX is mixed with calcium hydroxide at different time points. Mass spectrometry was performed to detect PCA in samples of 0.2% CHX and Ca(OH)2 mixed with 0.2% CHX. High-performance liquid chromatography was used to confirm the presence of CHX in the mixture with Ca(OH)2. The samples were analyzed immediately after mixing and after 7 and 14 days. During the intervals of the experiment, the samples were maintained at 36.5 degrees C and 95% relative humidity. PCA was detected in the 0.2% CHX solution after 14 days. The mixture of CHX with Ca(CH)2 liberated ROS at all time points, but no traces of CHX were present in the mixture as a result of immediate degradation of the CHX. (J Endod 2008;34:1508-1514)