Oral microbiota in Swiss adolescents.

Objectives: The purpose of the study was to determine the prevalence of different oral microbes in gingival plaque samples and in samples from the dorsum of the tongue in a Swiss adolescent population.

Materials And Methods: Ninety-nine adolescents between 15 and 18 years were enrolled. Plaque index, bleeding on probing (BOP), the periodontal screening index, and decayed missed filled tooth (DMFT) index were recorded.

A metalloproteinase karilysin present in the majority of Tannerella forsythia isolates inhibits all pathways of the complement system.

Tannerella forsythia is a poorly studied pathogen despite being one of the main causes of periodontitis, which is an inflammatory disease of the supporting structures of the teeth. We found that despite being recognized by all complement pathways, T. forsythia is resistant to killing by human complement, which is present at up to 70% of serum concentration in gingival crevicular fluid.

A systematic review of placement-related attrition in nurse education.

Background: Attrition in nurse education is a worldwide issue. Clinical placements form a major part of nurse education and have an important role in students' perceptions of nursing. Student nurses cite unsatisfactory placement experiences as a reason for leaving nursing education.

Microbial profile of patients with periodontitis compared with healthy subjects.

Objective: To define and compare the microbiologic profile of subgingival plaque in German patients with periodontitis (including aggressive and advanced chronic periodontitis) and healthy subjects and to determine significant association between isolates and clinical status. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythia are major periodontal pathogens, though it is recognized that other species may also contribute to the pathogenesis of periodontal disease.

Method And Materials: Thirty-three patients with clinical and radiologic proof of aggressive and advanced chronic periodontitis and 20 healthy subjects were enrolled in this study.

Characterization of Aggregatibacter actinomycetemcomitans strains in periodontitis patients in Germany.

Objectives: Aggregatibacter actinomycetemcomitans strains of serotype b and with a deletion of 530 bp in the promoter region of the leukotoxin gene (JP2 clone) are known to be associated with severe periodontitis. Our study was aimed to detect virulence genes of A. actinomycetemcomitans strains obtained from patients living in four German cities with different proportions of immigrants.

Periodontal pathogens affect the level of protease inhibitors in gingival crevicular fluid.

In periodontitis, an effective host-response is primarily related to neutrophils loaded with serine proteases, including elastase (NE) and protease 3 (PR3), the extracellular activity of which is tightly controlled by endogenous inhibitors. In vitro these inhibitors are degraded by gingipains, cysteine proteases produced by Porphyromonas gingivalis. The purpose of this study was to determine the level of selected protease inhibitors in gingival crevicular fluid (GCF) in relation to periodontal infection.

Microbiologic findings 1 year after partial- and full-mouth scaling in the treatment of moderate chronic periodontitis.

Objective: To investigate the impact on microbiologic variables of full-mouth scaling (FMS) and conventional scaling and root planing (cSRP) after 12 months.

Method And Materials: In a prospective randomized controlled clinical study, 37 volunteers with moderate chronic periodontitis were treated by FMS or by cSRP in two sessions at 4-week intervals. Clinical attachment level, probing depth, and bleeding on probing were recorded at baseline as well as at 6 and 12 months.

Efficacy of chlorhexidine digluconate-containing formulations and other mouthrinses against periodontopathogenic microorganisms.

Objective: To determine in vitro the action of chlorhexidine digluconate and different commercially available mouthrinses on oral microorganisms.

Method And Materials: Minimal inhibitory concentrations and possible induction of resistance by chlorhexidine digluconate, an essential oil-containing mouthwash and an amine fluoride/stannous fluoride solution, were determined against microorganisms normally found in the oral cavity (10 streptococci, 2 enterobacteria, 1 Candida albicans, 8 Porphyromonas gingivalis, 6 Aggregatibacter actinomycetemcomitans, and 1 Fusobacterium nucleatum). Further, the effect of a 1-minute exposure on cell and bacterial viability was studied.

Reversibility of experimental peri-implant mucositis compared with experimental gingivitis in humans.

Objective: To monitor clinical, microbiological and host-derived alterations occurring around teeth and titanium implants during the development of experimental gingivitis/mucositis and their respective healing sequence in humans.

Material And Methods: Fifteen subjects with healthy or treated periodontal conditions and restored with dental implants underwent an experimental 3-week period of undisturbed plaque accumulation in the mandible. Subsequently, a 3-week period with optimal plaque control was instituted.

Cleavage of IgG1 and IgG3 by gingipain K from Porphyromonas gingivalis may compromise host defense in progressive periodontitis.

Degradation of immunoglobulins is an effective strategy of bacteria to evade the immune system. We have tested whether human IgG is a substrate for gingipain K of Porphyromonas gingivalis and found that the enzyme can hydrolyze subclass 1 and 3 of human IgG. The heavy chain of IgG(1) was cleaved at a single site within the hinge region, generating Fab and Fc fragments.

Clinical and microbiologic results 12 months after scaling and root planing with different irrigation solutions in patients with moderate chronic periodontitis: a pilot randomized trial.

Background: The aim of this study is to determine in a randomized trial the impact on treatment outcome after 12 months of different subgingival irrigation solutions during scaling and root planing (SRP).

Methods: Fifty-one adult volunteers with generalized chronic periodontitis were treated by full-mouth SRP using 0.9% sodium chloride, 0.

Investigation of different approaches to reduce allergens in asthmatic children's homes--the Breath of Fresh Air Project, Cornwall, United Kingdom.

During 2001 to 2004, a study was conducted to assess the indoor environmental and health impact of installing allergen-reducing interventions in the homes of asthmatic children. Based on the results of a pilot study, to determine an intervention that would provide improved symptom scores and a reduction in house dust mite allergen (Der p 1), mechanical ventilation and heat recovery (MVHR) systems were installed in 16 homes. Environmental and respiratory health assessments were conducted before and after the installation of the MVHR systems.

Efficacy of taurolidine against periodontopathic species--an in vitro study.

The antimicrobial effect of taurolidine was tested against periodontopathic species in comparison to chlorhexidine digluconate in the presence or absence of serum. Minimal inhibitory concentrations (MIC), microbiocidal concentrations (MBC), as well as killing were determined against 32 different microbial strains including 3 Porphyromonas gingivalis, 3 Aggregatibacter actinomycetemcomitans, and 15 potentially superinfecting species with and without 25% v/v human serum. The MIC(50) of taurolidine against the tested microbial strains was 0.

Effect of ozone on periodontopathogenic species--an in vitro study.

The in vitro study was aimed to determine the effect of ozone on periodontopathogenic microorganisms. Ozone was generated for 6 s-2 × 24 s (corresponding to 0.56 mg-2 × 2.

Comparison of gingival crevicular fluid sampling methods in patients with severe chronic periodontitis.

Background: The analysis of samplings from periodontal pockets is important in the diagnosis and therapy of periodontitis. In this study, three different sampling techniques were compared to determine whether one method yielded samples suitable for the reproducible and simultaneous determination of bacterial load, cytokines, neutrophil elastase, and arginine-specific gingipains (Rgps). Rgps are an important virulence factor of Porphyromonas gingivalis, the exact concentration of which in gingival crevicular fluid (GCF) has not been quantified.

Comparison of real-time polymerase chain reaction and DNA-strip technology in microbiological evaluation of periodontitis treatment.

The impact of a semiquantitative commercially available test based on DNA-strip technology (microIDent®, Hain Lifescience, Nehren, Germany) on diagnosis and treatment of severe chronic periodontitis of 25 periodontitis patients was evaluated in comparison with a quantitative in-house real-time PCR. Subgingival plaque samples were collected at baseline as well as at 3, 6, and 12 months later. After extracting DNA, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and several other periodontopathogens were determined by both methods.

Adsorption of components of the plasma kinin-forming system on the surface of Porphyromonas gingivalis involves gingipains as the major docking platforms.

Enhanced production of proinflammatory bradykinin-related peptides, the kinins, has been suggested to contribute to the pathogenesis of periodontitis, a common inflammatory disease of human gingival tissues. In this report, we describe a plausible mechanism of activation of the kinin-generating system, also known as the contact system or kininogen-kallikrein-kinin system, by the adsorption of its plasma-derived components such as high-molecular-mass kininogen (HK), prekallikrein (PK), and Hageman factor (FXII) to the cell surface of periodontal pathogen Porphyromonas gingivalis. The adsorption characteristics of mutant strains deficient in selected proteins of the cell envelope suggested that the surface-associated cysteine proteinases, gingipains, bearing hemagglutinin/adhesin domains (RgpA and Kgp) serve as the major platforms for HK and FXII adhesion.

Light induced stimulation and delay of cardiac activity.

This article shows the combination of light activatable ion channels and microelectrode array (MEA) technology for bidirectionally interfacing cells. HL-1 cultures, a mouse derived cardiomyocyte-like cell line, transfected with channelrhodopsin were stimulated with a microscope coupled 473 nm laser and recorded with custom built 64 electrode MEAs. Channelrhodopsin induced depolarization of the cell can evoke action potentials (APs) in single cells.

Peptidylarginine deiminase from Porphyromonas gingivalis citrullinates human fibrinogen and α-enolase: implications for autoimmunity in rheumatoid arthritis.

Objective: To investigate protein citrullination by the periodontal pathogen Porphyromonas gingivalis as a potential mechanism for breaking tolerance to citrullinated proteins in rheumatoid arthritis (RA).

Methods: The expression of endogenous citrullinated proteins was analyzed by immunoblotting of cell extracts from P gingivalis and 10 other oral bacteria. P gingivalis-knockout strains lacking the bacterial peptidylarginine deiminases (PADs) or gingipains were created to assess the role of these enzymes in citrullination.

Mixture of periodontopathogenic bacteria influences interaction with KB cells.

Introduction: The purpose of this study was to investigate the adhesion and invasion of periodontopathogenic bacteria in varied mixed infections and the release of interleukins from an epithelial cell line (KB cells).

Methods: KB cells were co-cultured with Porphyromonas gingivalis ATCC 33277 and M5-1-2, Tannerella forsythia ATCC 43037, Treponema denticola ATCC 35405 and Fusobacterium nucleatum ATCC 25586 in single and mixed infections. The numbers of adherent and internalized bacteria were determined up to 18 h after bacterial exposure.

Serotypes of Aggregatibacter actinomycetemcomitans in patients with different ethnic backgrounds.

Background: The identification of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) serotypes may add some important information to the understanding of the pathogenetic background of severe periodontal infections. This study compared serotypes of A. actinomycetemcomitans in two groups of periodontal patients with different ethnic backgrounds.

Iridium oxide microelectrode arrays for in vitro stimulation of individual rat neurons from dissociated cultures.

We present the first in vitro extracellular stimulation of individual neurons from dissociated cultures with iridium oxide (IrO(x)) electrodes. Microelectrode arrays with sputtered IrO(x) films (SIROF) were developed for electrophysiological investigations with electrogenic cells. The microelectrodes were characterized with scanning electron and atomic force microscopy, revealing rough and porous electrodes with enlarged surface areas.

Influence of serum on interaction of Porphyromonas gingivalis ATCC 33277 and Aggregatibacter actinomycetemcomitans Y4 with an epithelial cell line.

Background And Objective: The purpose of this study was to investigate the influence of serum on the interaction of periodontal pathogens with epithelial cells using an epithelial cell line (KB cells). This is important because serum is a key component of gingival crevicular fluid and may influence inflammatory responses in epithelial cells exposed to periodontal pathogens.

Material And Methods: Porphyromonas gingivalis ATCC 33277 and Aggregatibacter actinomycetemcomitans Y4 were co-cultured with KB cells either with or without the addition of up to 10% human serum or 50 mg/mL human serum albumin.

The influence of a probiotic milk drink on the development of gingivitis: a pilot study.

Aim: The aim of this study was to determine the effect of a probiotic milk drink on gingival health and the development of experimental gingivitis.

Material And Methods: Fifty volunteer students took part in a parallel-designed non-blinded study. The test group drank a probiotic drink once a day; the control group did not receive any product to drink.

Interpain A, a cysteine proteinase from Prevotella intermedia, inhibits complement by degrading complement factor C3.

Periodontitis is an inflammatory disease of the supporting structures of the teeth caused by, among other pathogens, Prevotella intermedia. Many strains of P. intermedia are resistant to killing by the human complement system, which is present at up to 70% of serum concentration in gingival crevicular fluid.