Quantitative Proteomic Analysis of the Effect of Fluoride on the Acquired Enamel Pellicle

The acquired enamel pellicle (AEP) is a thin film formed by the selective adsorption of salivary proteins onto the enamel surface of teeth. The AEP forms a critical interface between the mineral phase of teeth (hydroxyapatite) and the oral microbial biofilm. This biofilm is the key feature responsible for the development of dental caries. Fluoride on enamel surface is well known to reduce caries by reducing the solubility of enamel to acid. Information on the effects of fluoride on AEP formation is limited. This study aimed to investigate the effects of fluoride treatment on hydroxyapatite on the subsequent formation of AEP. In addition, this study pioneered the use of label-free quantitative proteomics to better understand the composition of AEP proteins. Hydroxyapatite discs were randomly divided in 4 groups (n = 10 per group). Each disc was exposed to distilled water (control) or sodium fluoride solution (1, 2 or 5%) for 2 hours. Discs were then washed and immersed in human saliva for an additional 2 hours. AEP from each disc was collected and subjected to liquid chromatography electrospray ionization mass spectrometry for protein identification, characterization and quantification. A total of 45 proteins were present in all four groups, 12 proteins were exclusively present in the control group and another 19 proteins were only present in the discs treated with 5% sodium fluoride. Relative proteomic quantification was carried out for the 45 proteins observed in all four groups. Notably, the concentration of important salivary proteins, such as statherin and histatin 1, decrease with increasing levels of fluoride. It suggests that these proteins are repulsed when hydroxyapatite surface is coated with fluoride. Our data demonstrated that treatment of hydroxyapatite with fluoride (at high concentration) qualitatively and quantitatively modulates AEP formation, effects which in turn will likely impact the formation of oral biofilms.Natural Sciences and Engineering Research Council of Canada (NSERC) [371813]Natural Sciences and Engineering Research Council of Canada (NSERC)Canadian Institutes of Health Research (CIHR)Canadian Institutes of Health Research (CIHR) [106657, 97577]Canada Foundation for Innovation - Leaders Opportunity Fund (CFI-LOF) [25116]Canada Foundation for Innovation Leaders Opportunity Fund (CFILOF)CIHR New Investigator AwardCIHR New Investigator Award [113166

Predominant pathogen competition and core microbiota divergence in chronic airway infection

© 2015 International Society for Microbial Ecology All rights reserved. Chronic bacterial lung infections associated with non-cystic fibrosis bronchiectasis represent a substantial and growing health-care burden. Where Pseudomonas aeruginosa is the numerically dominant species within these infections, prognosis is significantly worse. However, in many individuals, Haemophilus influenzae predominates, a scenario associated with less severe disease. The mechanisms that determine which pathogen is most abundant are not known. We hypothesised that the distribution of H. influenzae and P. aeruginosa would be consistent with strong interspecific competition effects. Further, we hypothesised that where P. aeruginosa is predominant, it is associated with a distinct 'accessory microbiota' that reflects a significant interaction between this pathogen and the wider bacterial community. To test these hypotheses, we analysed 16S rRNA gene pyrosequencing data generated previously from 60 adult bronchiectasis patients, whose airway microbiota was dominated by either P. aeruginosa or H. influenzae. The relative abundances of the two dominant species in their respective groups were not significantly different, and when present in the opposite pathogen group the two species were found to be in very low abundance, if at all. These findings are consistent with strong competition effects, moving towards competitive exclusion. Ordination analysis indicated that the distribution of the core microbiota associated with each pathogen, readjusted after removal of the dominant species, was significantly divergent (analysis of similarity (ANOSIM), R=0.07, P=0.019). Taken together, these findings suggest that both interspecific competition and also direct and/or indirect interactions between the predominant species and the wider bacterial community may contribute to the predominance of P. aeruginosa in a subset of bronchiectasis lung infections

Filgrastim helps to heal herpes zoster faster: Two case reports

Herpes zoster is an infectious disease caused by varicella-zoster virus that may occur sporadically at any age. We report on two patients with herpes zoster who received chemotherapy for breast cancer. Both patients were immunocompromised and received filgrastimtherapy for themanagement of neutropenia. Zoster occurred during filgrastim therapy but the symptoms were alleviated rapidly in the course of therapy. We conclude that granulocyte colony-stimulating factor therapy helped symptom alleviation and accelerated the recovery fromherpes zoster in our chemotherapy-treated patients. Free full text available at www.tumorionline.it