Oral prednisolone for 4 days does not increase exercise tolerance in men with COPD

One of the primary objectives in management of chronic obstructive pulmonary disease (COPD) is preventing decrease in lung function and reducing the annual number of acute exacerbations of COPD (AECOPD). An oral course of systemic corticosteroids is a commonly used treatment in AECOPD. We hypothesize that this treatment also increases exercise performance and decreases muscle fatigue. In a randomized double-blinded, parallel, placebo-controlled trial, we investigated 14 men (8 on prednisolone 37.5 mg vs. 6 on placebo) with severe and very severe COPD. For 5 consecutive days, the patients performed a submaximal endurance test measuring time to exhaustion (TTE, primary endpoint), spirometry, maximal inspiratory and expiratory pressure and maximal isometric contraction of the quadriceps femoris muscle (maximum voluntary contraction (MVC)). At visits 2, 3 and 4, a fatigue protocol was carried out after 40 minutes of cycling at 40% of maximal effort. No differences between groups were found for TTE, lung function or maximal inspiratory or expiratory pressure, however, patients on prednisolone showed significant increased MVC: median 5.15 [3.35; 9.15] against placebo: −2 [−5.57; 3.95] (p = 0.03). This finding indicates an impact of corticosteroids on muscle groups being exposed to submaximal endurance.

Retrospective Analysis of Serotype Switching of Vibrio cholerae O1 in a Cholera Endemic Region Shows It Is a Non-random Process

Genomic data generated from clinical Vibrio cholerae O1 isolates collected over a five year period in an area of Kolkata, India with seasonal cholera outbreaks allowed a detailed genetic analysis of serotype switching that occurred from Ogawa to Inaba and back to Ogawa. The change from Ogawa to Inaba resulted from mutational disruption of the methyltransferase encoded by the wbeT gene. Re-emergence of the Ogawa serotype was found to result either from expansion of an already existing Ogawa clade or reversion of the mutation in an Inaba clade. Our data suggests that such transitions are not random events but rather driven by as yet unidentified selection mechanisms based on differences in the structure of the O1 antigen or in the serotype-determining wbeT gene.

Cholera is a major health problem in many parts of the world causing seasonal outbreaks in endemic areas. Essentially only the O1 serogroup of Vibrio cholerae causes epidemic cholera. This serogroup has two immunologically distinguishable serotype variants called Ogawa and Inaba. The Inaba serotype is a consequence of a mutation in a single gene, wbeT, that in its intact form encodes for an enzyme that methylates the terminal perosamine sugar of the lipopolysaccharide side chain thus resulting in the Ogawa serotype. By careful examination over a five-year period of the genetic lineages of bacteria causing cholera in an endemic area we show data indicating that serotype switching is not a random process but is driven by selection pressures that have yet to be identified.

Construction and preclinical evaluation of mmCT, a novel mutant cholera toxin adjuvant that can be efficiently produced in genetically manipulated Vibrio cholerae

There is an urgent need for new adjuvants that are effective with mucosally administered vaccines. Cholera toxin (CT) is the most powerful known mucosal adjuvant but is much too toxic for human use. In an effort to develop a useful mucosal adjuvant we have generated a novel non-toxic mutant CT molecule that retains much of the adjuvant activity of native CT. This was achieved by making the enzymatically active A subunit (CTA) recalcitrant to the site-specific proteolytic cleavage ("nicking") required for toxicity, which was found to require mutations not only in the two residues rendering the molecule resistant to trypsin but also in neighboring sites protecting against cleavage by Vibrio cholerae proteases. This multiple-mutated CT (mmCT) adjuvant protein could be efficiently produced in and purified from the extracellular medium of CT-deleted V. cholerae. The mmCT completely lacked detectable enterotoxicity in an infant mouse model and had >1000-fold reduced cAMP inducing activity compared to native CT in a sensitive mammalian target cell system. It nonetheless proved to have potent adjuvant activity on mucosal and systemic antibody as well as cellular immune responses to mucosally co-administered antigens including oral cholera and intranasal influenza vaccines. We conclude that mmCT is an attractive novel non-toxic mucosal adjuvant for enhancing immune responses to co-administered mucosal vaccines.

Development of stable Vibrio cholerae O1 Hikojima type vaccine strains co-expressing the Inaba and Ogawa lipopolysaccharide antigens

We describe here the development of stable classical and El Tor V. cholerae O1 strains of the Hikojima serotype that co–express the Inaba and Ogawa antigens of O1 lipopolysaccharide (LPS). Mutation of the wbeT gene reduced LPS perosamine methylation and thereby gave only partial transformation into Ogawa LPS on the cell surface. The strains express approximately equal amounts of Inaba– and Ogawa–LPS antigens which are preserved after formalin–inactivation of the bacteria. Oral immunizations of both inbred and outbred mice with formalin–inactivated whole–cell vaccine preparations of these strains elicited strong intestinal IgA anti–LPS as well as serum vibriocidal antibody responses against both Inaba and Ogawa that were fully comparable to the responses induced by the licensed Dukoral vaccine. Passive protection studies in infant mice showed that immune sera raised against either of the novel Hikojima vaccine strains protected baby mice against infection with virulent strains of both serotypes. This study illustrates the power of using genetic manipulation to improve the properties of bacteria strains for use in killed whole–cell vaccines.

A randomized 5-year clinical evaluation of 3 ceramic inlay systems

PURPOSE

The present follow-up study aimed to evaluate the clinical quality and longevity of 3 ceramic inlay systems and compare them with gold inlays.

MATERIALS AND METHODS

Twenty patients were treated with one Cerec, one Mirage, one Empress, and one gold inlay, respectively, inserted in a randomly selected order in the mandible. The inlays were examined independently by 2 calibrated examiners immediately after and 1, 3, and 5 years after luting. The inlays were rated using the California Dental Association (CDA) quality evaluation system.

RESULTS

Two Empress inlays required replacement because of fracture between examination (Ex) 1 and Ex 2, and 2 Empress inlays were fractured between Ex 3 and Ex 4. One Cerec inlay had to be recemented after 3 months, and one Cerec inlay fractured between Ex 3 and Ex 4 and was replaced with a gold inlay. Examination showed that the mismatch of color increased from 15% to 50% between Ex 1 and Ex 4 for all ceramic systems. Visible evidence of ditching along the margin increased from 5% at Ex 1 to 70% at Ex 4, and an apparent discoloration of the margin between the tooth and the restoration was seen in 0% to 5% at Ex 1 compared to 30% to 55% at Ex 4.

CONCLUSION

Eight percent of the ceramic inlays were fractured during the follow-up period of 5 years. Based on the criteria of the CDA quality evaluation system, 92% of the 60 ceramic inlays and 100% of the 20 gold inlays were rated satisfactory 5 years after luting.

Influence of film thickness on joint bend strength of a ceramic/resin composite joint

OBJECTIVES

The purpose of this study was to evaluate the influence of different film thicknesses of resin composite luting agents on the joint bend strength of a ceramic/resin interface.

METHODS

Mirage FLC (Chamelon Dental Products) and Vita Cerec (Coltène AG) duo cement were used in combination with the ceramic materials, Mirage and Vita Cerec blocks. Cement layers with thicknesses of 20 microns, 50 microns, 100 microns and 200 microns were light-cured with a high-intensity curing light. Ten specimens of each ceramic/cement combination and thickness provided a total of 80 complete test specimens. Each specimen was placed in a four-point bending jig mounted in a universal tensile testing machine and underwent loading. A paired two-tailed Student's 1-test was used to evaluate differences between different series of film thicknesses and resin cement combinations.

RESULTS

Within each ceramic/cement combination, the bond strength values were significantly lower for the 20 micron film then the thicker films.

SIGNIFICANCE

Taking into account the physical and clinical properties of resin-based luting agents, available knowledge indicates that a marginal gap on the order of 50-100 microns seems to optimize performance.

A microcomputer system for physiological data collection and analysis

The ability to monitor and record activity within the masticatory system is of importance to both general practitioner and research worker. Recent developments in physiological data collection and analysis at the Department of Anatomy, University of Queensland, have achieved that objective in a simple and cost-effective manner. Recording, printing, plotting, and a wide range of analysis procedures can be undertaken utilizing relatively inexpensive available computers.

Clinical evaluation of restoration margins by an endoscopic microscope

A method is presented for high magnification, clinical examination and recording of the marginal fit of dental restorations. An endoscopic microscope used in conjunction with video recording facilities affords acceptable colour records of restorative procedures for monitoring purposes. The suggestion is made that the concept of 'fit' in the clinical context has not been adequately addressed. The technique described has other clinical and research implications.