Bronchoconstriction and airway hyperresponsiveness after ovalbumin inhalation in sensitized mice

To investigate the mechanisms underlying airway hyperresponsiveness a murine model was developed with several important characteristics of human allergic asthma. Mice were intraperitoneally sensitized with ovalbumin and after 4 weeks challenge via an ovalbumin aerosol. After aerosol, lung function was evaluated with a non-invasive forced oscillation technique. The amount of mucosal exudation into the airway lumen and the presence of mast cell degranulation was determined. Tracheal responsiveness was measured at several time points after challenge. At these time points also bronchoalveolar lavage and histology were performed. Sensitization induced high antigen-specific IgE levels in serum. Inhalation of ovalbumin in sensitized mice induced an immediate but no late bronchoconstrictive response. During this immediate phase, respiratory resistance was increased (54%). Within the first hour after ovalbumin inhalation increased mucosal exudation and mast cell degranulation were observed. At 12 and 24 h after ovalbumin challenge, mice showed tracheal hyperresponsiveness (29% and 34%, respectively). However, no apparent inflammation was found in the lungs or bronchoalveolar lavage. From these results it can be concluded that hyperresponsiveness can develop via mechanisms independent of an inflammatory infiltrate. Since mast cell degranulation occurred after ovalbumin exposure, we hypothesize that mast cells are involved in the induction of airway hyperresponsiveness in this model

Nanophase hydroxyapatite as a biomaterial in advanced hard tissue engineering: a review

Item does not contain fulltextHydroxyapatite is a biocompatible material that is extensively used in the replacement and regeneration of bone material. In nature, nanostructured hydroxyapatite is the main component present in hard body tissues. Hence, the state of the art in nanotechnology can be exploited to synthesize nanophase hydroxyapatite that has similar properties with natural hydroxyapatite. Sustainable methods to mass-produce synthetic hydroxyapatite nanoparticles are being developed to meet the increasing demand for these materials and to further develop the progress made in hard tissue regeneration, especially for orthopedic and dental applications. This article reviews the current developments in nanophase hydroxyapatite through various manufacturing techniques and modifications

A Balance of Capping Protein and Profilin Functions Is Required to Regulate Actin Polymerization in Drosophila Bristle

Profilin is a well-characterized protein known to be important for regulating actin filament assembly. Relatively few studies have addressed how profilin interacts with other actin-binding proteins in vivo to regulate assembly of complex actin structures. To investigate the function of profilin in the context of a differentiating cell, we have studied an instructive genetic interaction between mutations in profilin (chickadee) and capping protein (cpb). Capping protein is the principal protein in cells that caps actin filament barbed ends. When its function is reduced in the Drosophila bristle, F-actin levels increase and the actin cytoskeleton becomes disorganized, causing abnormal bristle morphology. chickadee mutations suppress the abnormal bristle phenotype and associated abnormalities of the actin cytoskeleton seen in cpb mutants. Furthermore, overexpression of profilin in the bristle mimics many features of the cpb loss-of-function phenotype. The interaction between cpb and chickadee suggests that profilin promotes actin assembly in the bristle and that a balance between capping protein and profilin activities is important for the proper regulation of F-actin levels. Furthermore, this balance of activities affects the association of actin structures with the membrane, suggesting a link between actin filament dynamics and localization of actin structures within the cell

Development of a reference material for analysing naturally occurring radioactive material from the steel industry

Accurate measurement of naturally occurring radionuclides in blast furnace slag, a by-product of the steel industry, is required for compliance with building regulations where it is often used as an ingredient in cement. A matrix reference blast furnace slag material has been developed to support traceability in these measurements. Raw material provided by a commercial producer underwent stability and homogeneity testing, as well as characterisation of matrix constituents, to provide a final candidate reference material. The radionuclide content was then determined during a comparison exercise that included 23 laboratories from 14 countries. Participants determined the activity per unit mass for 226Ra, 232Th and 40K using a range of techniques. The consensus values obtained from the power-moderated mean of the reported participant results were used as indicative activity per unit mass values for the three radionuclides: A0(226Ra) = 106.3 (34) Bq·kg−1, A0(232Th) = 130.0 (48) Bq·kg−1 and A0(40K) = 161 (11) Bq·kg−1 (where the number in parentheses is the numerical value of the combined standard uncertainty referred to the corresponding last digits of the quoted result). This exercise helps to address the current shortage of NORM industry reference materials, putting in place infrastructure for production of further reference materials.[Display omitted]•Current availability of reference materials for naturally occurring radioactive material has been expanded upon.•A blast furnace slag reference material has been developed to support the steel industry and regulations regarding its use in building materials.•A comparison exercise of 23 laboratories was used to determine consensus values for the activity per unit mass of selected radionuclides.•Infrastructure has been built for future development of reference materials in support of naturally occurring radioactive materials

Molecular Dissection of Cytokinesis by RNA Interference in Drosophila Cultured Cells

We have used double-stranded RNA-mediated interference (RNAi) to study Drosophila cytokinesis. We show that double-stranded RNAs for anillin, acGAP, pavarotti, rho1, pebble, spaghetti squash, syntaxin1A, and twinstar all disrupt cytokinesis in S2 tissue culture cells, causing gene-specific phenotypes. Our phenotypic analyses identify genes required for different aspects of cytokinesis, such as central spindle formation, actin accumulation at the cell equator, contractile ring assembly or disassembly, and membrane behavior. Moreover, the cytological phenotypes elicited by RNAi reveal simultaneous disruption of multiple aspects of cytokinesis. These phenotypes suggest interactions between central spindle microtubules, the actin-based contractile ring, and the plasma membrane, and lead us to propose that the central spindle and the contractile ring are interdependent structures. Finally, our results indicate that RNAi in S2 cells is a highly efficient method to detect cytokinetic genes, and predict that genome-wide studies using this method will permit identification of the majority of genes involved in Drosophila mitotic cytokinesis