On the dynamics of nitrite, nitrate and other biomarkers of nitric oxide production in inflammatory bowel disease

Nitrite and nitrate are frequently used surrogate markers of nitric oxide (NO) production. Using rat models of acute and chronic DSS-induced colitis we examined the applicability of these and other NO-related metabolites, in tissues and blood, for the characterization of inflammatory bowel disease. Global NO dynamics were assessed by simultaneous quantification of nitrite, nitrate, nitroso and nitrosyl species over time in multiple compartments. NO metabolite levels were compared to a composite disease activity index (DAI) and contrasted with measurements of platelet aggregability, ascorbate redox status and the effects of 5-aminosalicylic acid (5-ASA). Nitroso products in the colon and in other organs responded in a manner consistent with the DAI. In contrast, nitrite and nitrate, in both intra- and extravascular compartments, exhibited variations that were not always in step with the DAI. Extravascular nitrite, in particular, demonstrated significant temporal instabilities, ranging from systemic drops to marked increases. The latter was particularly evident after cessation of the inflammatory stimulus and accompanied by profound ascorbate oxidation. Treatment with 5-ASA effectively reversed these fluctuations and the associated oxidative and nitrosative stress. Platelet activation was enhanced in both the acute and chronic model. Our results offer a first glimpse into the systemic nature of DSS-induced inflammation and reveal a greater complexity of NO metabolism than previously envisioned, with a clear dissociation of nitrite from other markers of NO production. The remarkable effectiveness of 5-ASA to abrogate the observed pattern of nitrite instability suggests a hitherto unrecognized role of this molecule in either development or resolution of inflammation. Its possible link to tissue oxygen consumption and the hypoxia that tends to accompany the inflammatory process warrants further investigation

First observations with CONDOR, a 1.5 THz heterodyne receiver

The THz atmospheric windows centered at roughly 1.3 and 1.5~THz, contain numerous spectral lines of astronomical importance, including three high-J CO lines, the N+ line at 205 microns, and the ground transition of para-H2D+. The CO lines are tracers of hot (several 100K), dense gas; N+ is a cooling line of diffuse, ionized gas; the H2D+ line is a non-depleting tracer of cold (~20K), dense gas. As the THz lines benefit the study of diverse phenomena (from high-mass star-forming regions to the WIM to cold prestellar cores), we have built the CO N+ Deuterium Observations Receiver (CONDOR) to further explore the THz windows by ground-based observations. CONDOR was designed to be used at the Atacama Pathfinder EXperiment (APEX) and Stratospheric Observatory For Infrared Astronomy (SOFIA). CONDOR was installed at the APEX telescope and test observations were made to characterize the instrument. The combination of CONDOR on APEX successfully detected THz radiation from astronomical sources. CONDOR operated with typical Trec=1600K and spectral Allan variance times of 30s. CONDOR's first light observations of CO 13-12 emission from the hot core Orion FIR4 (= OMC1 South) revealed a narrow line with T(MB) = 210K and delta(V)=5.4km/s. A search for N+ emission from the ionization front of the Orion Bar resulted in a non-detection. The successful deployment of CONDOR at APEX demonstrates the potential for making observations at THz frequencies from ground-based facilities.Comment: 4 pages + list of objects, 3 figures, to be published in A&A special APEX issu

The Use of Spinning-Disk Confocal Microscopy for the Intravital Analysis of Platelet Dynamics in Response to Systemic and Local Inflammation

Platelets are central players in inflammation and are an important component of the innate immune response. The ability to visualize platelets within the live host is essential to understanding their role in these processes. Past approaches have involved adoptive transfer of labelled platelets, non-specific dyes, or the use of fluorescent antibodies to tag platelets in vivo. Often, these techniques result in either the activation of the platelet, or blockade of specific platelet receptors. In this report, we describe two new methods for intravital visualization of platelet biology, intravenous administration of labelled anti-CD49b, which labels all platelets, and CD41-YFP transgenic mice, in which a percentage of platelets express YFP. Both approaches label endogenous platelets and allow for their visualization using spinning-disk confocal fluorescent microscopy. Following LPS-induced inflammation, we were able to measure a significant increase in both the number and size of platelet aggregates observed within the vasculature of a number of different tissues. Real-time observation of these platelet aggregates reveals them to be large, dynamic structures that are continually expanding and sloughing-off into circulation. Using these techniques, we describe for the first time, platelet recruitment to, and behaviour within numerous tissues of the mouse, both under control conditions and following LPS induced inflammation

Single-source macroporous hybrid materials by melt-shear organization of core-shell particles

The preparation of porous materials is an interesting field for a huge variety of potential applications. Herein we report an efficient and convenient strategy for the creation of inverse colloidal crystal structures based on soft core/shell polymer particle templating. This single-source strategy is based on starved-feed emulsion polymerization of hybrid core/shell particles consisting of a poly(methyl methacrylate-co-allyl methacrylate) (P(MMA-co-ALMA)) core and a poly(ethyl acrylate-co-(3-methacryloxypropyl-trimethoxysilane)) (PEA-co-PMEMO) shell. The resulting monodisperse particles are analyzed with respect to their size and distribution by transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements. The hybrid monodisperse core/shell particles can be aligned to a colloidal crystal by using the convenient melt-shear organization technique. As a result, free-standing and crack-free hybrid polymer colloidal crystal films are accessible without the need of any solvent or dispersion medium. The processing step is investigated regarding different parameters comprising temperature and pressure for the influence on the colloidal crystal film formation. Furthermore, resulting core/shell ratio is tailored by starved-feed emulsion polymerization conditions, since the ratio affects the quality of the porous structure after thermal treatment of colloidal crystal films. The incorporation of alkoxysilane-containing monomers offers a unique crosslinking strategy that yields mechanically robust and thermally stable films. Due to the increased stability, a removal of PMMA cores is possible by thermal treatment of the templating colloidal crystal films leading to almost isoporous free-standing hybrid materials as determined by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM)

Correlation Reflectometry at TEXTOR

In high temperature fusion plasmas the transport of energy and particles is commonly believed to be driven by turbulence. Turbulence quantities as correlation length and decorrelation time are important for the confinement properties of a plasma. Besides other diagnostics, correlation reflectometry has proven to be a suitable tool for the measurement of turbulence properties. At the medium sized Toroidal EXperiment for Technical Oriented Research (TEXTOR) the existing correlation reflectometry has been recently upgraded. A new reflectometer based on a microwave synthesizer has been developed and installed for the investigation of turbulence properties in a fusion plasma. Together with the existing reflectometer the measurement of radial correlation length and decorrelation time becomes available. Both reflectometers are computer controlled and allow to program individual frequency sequences and the duration of each frequency step. With the existing poloidal antenna array at θ=0° and on top of the vacuum vessel, the system allows the measurement of radial correlation and poloidal correlations at the same time. First experiments have been performed and the results on the radial correlation length of density fluctuations in a fusion plasma are presented

Redox- and mechano-chromic response of metallopolymer-based elastomeric colloidal crystal films

A novel and convenient route for the preparation of monodisperse ferrocene-containing core-interlayer-shell particles using emulsion polymerisation protocols is described. These metallopolymer-based particles can be used to produce highly ordered elastomeric opal films with fascinating distinct reflection colours. The present work additionally describes the combined addressability of both stimuli, redox-chemistry and mechanical stress. The obtained materials are interesting since application of the melt-shear process followed by crosslinking of the matrix provides access to large-area, mechano-responsive elastomeric opal films featuring an additional redox response. Both, basic synthesis aspects and first steps towards application in the field of stimuli-responsive sensing of respective materials are discussed

Redox- and mechano-chromic response of metallopolymer-based elastomeric colloidal crystal films

A novel and convenient route for the preparation of monodisperse ferrocene-containing core-interlayer-shell particles using emulsion polymerisation protocols is described. These metallopolymer-based particles can be used to produce highly ordered elastomeric opal films with fascinating distinct reflection colours. The present work additionally describes the combined addressability of both stimuli, redox-chemistry and mechanical stress. The obtained materials are interesting since application of the melt-shear process followed by crosslinking of the matrix provides access to large-area, mechano-responsive elastomeric opal films featuring an additional redox response. Both, basic synthesis aspects and first steps towards application in the field of stimuli-responsive sensing of respective materials are discussed