Exposure to the Dental Environment and Prevalence of Respiratory Illness in Dental Student Populations

Objective: To determine if the prevalence of respiratory disease among dental students and dental residents varies with their exposure to the clinical dental environment. Methods: A detailed questionnaire was administered to 817 students at 3 dental schools. The questionnaire sought information concerning demographic characteristics, school year, exposure to the dental environment and dental procedures, and history of respiratory disease. The data obtained were subjected to bivariate and multiple logistic regression analysis. Results: Respondents reported experiencing the following respiratory conditions during the previous year: asthma (26 cases), bronchitis (11 cases), chronic lung disease (6 cases), pneumonia (5 cases) and streptococcal pharyngitis (50 cases). Bivariate statistical analyses indicated no significant associations between the prevalence of any of the respiratory conditions and year in dental school, except for asthma, for which there was a significantly higher prevalence at 1 school compared to the other 2 schools. When all cases of respiratory disease were combined as a composite variable and subjected to multivariate logistic regression analysis controlling for age, sex, race, dental school, smoking history and alcohol consumption, no statistically significant association was observed between respiratory condition and year in dental school or exposure to the dental environment as a dental patient. Conclusion: No association was found between the prevalence of respiratory disease and a student\u27s year in dental school or previous exposure to the dental environment as a patient. These results suggest that exposure to the dental environment does not increase the risk for respiratory infection in healthy dental health care workers

Interaction of Salivary alpha-Amylase and Amylase-Binding-Protein A (AbpA) of Streptococcus gordonii with Glucosyltransferase of S. gordonii and Streptococcus mutans

<p>Abstract</p> <p>Background</p> <p>Glucosyltransferases (Gtfs), enzymes that produce extracellular glucans from dietary sucrose, contribute to dental plaque formation by <it>Streptococcus gordonii </it>and <it>Streptococcus mutans</it>. The alpha-amylase-binding protein A (AbpA) of <it>S. gordonii</it>, an early colonizing bacterium in dental plaque, interacts with salivary amylase and may influence dental plaque formation by this organism. We examined the interaction of amylase and recombinant AbpA (rAbpA), together with Gtfs of <it>S. gordonii </it>and <it>S. mutans</it>.</p> <p>Results</p> <p>The addition of salivary alpha-amylase to culture supernatants of <it>S. gordonii </it>precipitated a protein complex containing amylase, AbpA, amylase-binding protein B (AbpB), and the glucosyltransferase produced by <it>S. gordonii </it>(Gtf-G). rAbpA was expressed from an inducible plasmid, purified from <it>Escherichia coli </it>and characterized. Purified rAbpA, along with purified amylase, interacted with and precipitated Gtfs from culture supernatants of both <it>S. gordonii </it>and <it>S. mutans</it>. The presence of amylase and/or rAbpA increased both the sucrase and transferase component activities of <it>S. mutans </it>Gtf-B. Enzyme-linked immunosorbent assay (ELISA) using anti-Gtf-B antibody verified the interaction of rAbpA and amylase with Gtf-B. A <it>S. gordonii abp</it>A-deficient mutant showed greater biofilm growth under static conditions than wild-type in the presence of sucrose. Interestingly, biofilm formation by every strain was inhibited in the presence of saliva.</p> <p>Conclusion</p> <p>The results suggest that an extracellular protein network of AbpA-amylase-Gtf may influence the ecology of oral biofilms, likely during initial phases of colonization.</p

Nosocomial Pneumonia and Oral Health

This article will critically review the evidence linking pneumonia to the aspiration of microbe-laden oropharyngeal secretions and tie that to the predisposition for these processes to affect dependent, medically compromised individuals. The goal of this review is to alert the reader to the role that oral disease and oral health play in fostering and preventing, respectively, widespread and potentially fatal pulmonary disease among high-risk individuals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73840/1/j.1754-4505.2005.tb01647.x.pd

Genetic relationships between Candida albicans strains isolated from dental plaque, trachea, and bronchoalveolar lavage fluid from mechanically ventilated intensive care unit patients

Candida albicans often resides in the oral cavity of healthy humans as a harmless commensal organism. This opportunistic fungus can cause significant disease in critically ill patients, such as those undergoing mechanical ventilation in the intensive care unit (ICU) having compromised local airway defense mechanisms. The goal of this study was to determine the intra- and inter-patient genetic relationship between strains of C. albicans recovered from dental plaque, tracheal secretions, and the lower airway by bronchoalveolar lavage of patients undergoing mechanical ventilation. Three pulsed-field gel electrophoresis (PFGE) typing methods were used to determine the genetic relatedness of the C. albicans strains, including electrophoretic karyotyping (EK) and restriction endonuclease analysis of the genome using SfiI (REAG-S) and BssHII (REAG-B). The C. albicans isolates from dental plaque and tracheo-bronchial sites from the same patient were genetically indistinguishable and retained over time, whereas strains from different patients usually separated into different genotypes. Among the three methods, REAG-B proved to be the most discriminatory method to differentiate isolates. The finding of genetically similar strains from the oral and tracheo-bronchial sites from the same patient supports the notion that the oral cavity may serve as an important source for C. albicans spread to the trachea and lung of mechanically ventilated patients

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

Galaxy bulges and their massive black holes: a review

With references to both key and oft-forgotten pioneering works, this article starts by presenting a review into how we came to believe in the existence of massive black holes at the centres of galaxies. It then presents the historical development of the near-linear (black hole)-(host spheroid) mass relation, before explaining why this has recently been dramatically revised. Past disagreement over the slope of the (black hole)-(velocity dispersion) relation is also explained, and the discovery of sub-structure within the (black hole)-(velocity dispersion) diagram is discussed. As the search for the fundamental connection between massive black holes and their host galaxies continues, the competing array of additional black hole mass scaling relations for samples of predominantly inactive galaxies are presented.Comment: Invited (15 Feb. 2014) review article (submitted 16 Nov. 2014). 590 references, 9 figures, 25 pages in emulateApJ format. To appear in "Galactic Bulges", E. Laurikainen, R.F. Peletier, and D.A. Gadotti (eds.), Springer Publishin