Absence of gastrointestinal infections in a cohort of patients with Zollinger-Ellison syndrome and other acid hypersecretors receiving long-term acid suppression with lansoprazole

<p>Abstract</p> <p>Background</p> <p>The relationship between proton pump inhibitor therapy and other acid suppressing medications and the risk of gastrointestinal infections remains controversial.</p> <p>Methods</p> <p>Patients enrolled in a long-term trial of lansoprazole for Zollinger-Ellison syndrome and other acid hypersecretory states had interval histories taken every six months regarding hospitalizations or other intercurrent medical conditions. All medications taken were also reviewed at each visit. In addition, available patients were specifically queried during the study period 2006–2007 regarding the development of any gastrointestinal infections, hospitalizations, and prescriptions for antibiotics.</p> <p>Results</p> <p>Ninety patients were enrolled in our long-term study and 81 were available for review. The median basal gastric pH for the cohort after stabilization on therapy was 2.9 and ranged from 1.1 – 8.4 with a median pentagastrin stimulated gastric pH of 1.60 (range 1.0 – 8.2). No patient developed a clinically significant gastrointestinal infection during the study. The median patient years of follow-up were 6.25 years.</p> <p>Conclusion</p> <p>In a cohort of patients with gastric acid hypersecretion in whom acid secretion status was monitored on lansoprazole, all were free of significant gastrointestinal infections on long-term follow-up.</p> <p>Trial registration</p> <p>NCT00204373</p

Significant Reduction of Antibiotic Use in the Community after a Nationwide Campaign in France, 2002–2007

Didier Guillemot and colleagues describe the evaluation of a nationwide programme in France aimed at decreasing unnecessary outpatient prescriptions for antibiotics. The campaign was successful, particularly in reducing prescriptions for children

Differential gene expression in male and female rainbow trout embryos prior to the onset of gross morphological differentiation of the gonads

<p>Abstract</p> <p>Background</p> <p>There are large differences between the sexes at the genetic level; these differences include heterogametic sex chromosomes and/or differences in expression of genes between the sexes. In rainbow trout (<it>Oncorhynchus mykiss</it>) qRT-PCR studies have found significant differences in expression of several candidate sex determining genes. However, these genes represent a very small fraction of the genome and research in other species suggests there are large portions of the transcriptome that are differentially expressed between the sexes. These differences are especially noticeable once gonad differentiation and maturation has occurred, but less is known at earlier stages of development. Here we use data from a microarray and qRT-PCR to identify genes differentially expressed between the sexes at three time points in pre-hatch embryos, prior to the known timing of sexual differentiation in this species.</p> <p>Results</p> <p>The microarray study revealed 883 differentially expressed features between the sexes with roughly equal numbers of male and female upregulated features across time points. Most of the differentially expressed genes on the microarray were not related to sex function, suggesting large scale differences in gene expression between the sexes are present early in development. Candidate gene analysis revealed <it>sox9</it>, <it>DMRT1</it>, <it>Nr5a1 </it>and <it>wt1 </it>were upregulated in males at some time points and <it>foxl2</it>, <it>ovol1</it>, <it>fst </it>and <it>cyp19a1a </it>were upregulated in females at some time points.</p> <p>Conclusion</p> <p>This is the first study to identify sexual dimorphism in expression of the genome during embryogenesis in any fish and demonstrates that transcriptional differences are present before the completion of gonadogenesis.</p

Mécanisme de dégradation thermique d'un FKM réticulé au peroxyde en présence de TAIC

En raison de leur résistance élevée à la chaleur, aux produits chimiques et aux contraintes mécaniques, les fluoroélastomères (FKM) sont largement utilisés dans divers domaines de l'industrie aéronautique. Toutefois, les avancées technologiques récentes dans ce secteur exigent des matériaux capables de résister à des températures encore plus élevées, ce qui met à l'épreuve les limites thermiques des FKM.Actuellement, lorsqu’une meilleure stabilité thermique est recherchée, la réticulation au peroxyde est privilégiée. Cette réaction se réalise le plus souvent en présence d’une molécule multifonctionnelle, appelée coagent, améliorant le rendement [1]. Des auteurs ont étudié la dégradation d’autres matrices fluorées, telles que le FFKM [2] et le TFE/P [3]. Au premier stade de vieillissement, la dégradation d’un coagent est observée, entrainant une diminution de la densité de réticulation.Dans ce contexte, cette étude expérimentale cherche à définir l’ensemble des étapes inhérentes à la dégradation d’un FKM réticulé au peroxyde en présence d’un coagent : le TAIC.Pour ce faire, un mélange FKM/Peroxyde/TAIC a été formulé pour étudier le mécanisme de dégradation et son impact sur la structure de l’élastomère. Ainsi, des analyses sur matériau neuf et sur matériaux vieillis à 250°C pendant différentes durées ont été réalisées

Multi-scale characterization of the (visco)elastic properties of a semicrystalline polymer

The high degree of heterogeneity of polymeric materials makes it difficult to describe their overall mechanical behavior. An access to information on a smaller scale is thus essential. Moreover, the mechanical response of these materials strongly depends on the microstructure developed during process especially for semicrystalline polymers. With the idea to better understand the relationships between structure and mechanical properties it is becoming necessary to develop multi-scale mechanical characterizations and instrumented indentation proves to be the most appropriate tool.Initially developed for the study of metallic and ceramic materials, it appeared that its application to polymeric materials presented some difficulties because of the viscous nature of these materials. Thus, as regards the study of viscoelastic properties by instrumented indentation, two complementary paths can be adopted: static nanoindentation (quite commonly used) and dynamic nanoindentation. Nevertheless, rigorous protocols remain to be developed to study properly time dependent materials.The aim of this work is to compare the local mechanical properties of a polypropylene obtained by compression molding and injection. The latter is known to exhibit a skin-core morphology [1] with a nonspherulitic skin and a typically spherulitic core. Afterwards, the viscoelastic properties are investigated at different scales using both dynamic nanoindentation [2] and dynamic mechanical analysis (DMA). Experiments were performed at temperatures between room temperature and 120°C and various frequencies over the range 0.1 – 100 Hz.Regarding quasi-static indentation, the characterization of the local properties through the sample thickness highlights the heterogeneity of the morphology in the injected sample with a skin layer softer than the core whereas the compression-molded sample displays more homogeneous properties. If the elastic properties are different in the injected sample through the thickness, the frequency dependence is similar and no skin-core effect is highlighted.From the nano-DMA results, it was possible to construct a master curve as it commonly done from DMA experiments for the injected polypropylene as illustrated in Figure 1. The frequency tests have been performed on the skin. The evolution of the storage modulus is similar at the two scales with an increase with the frequency. The Arrhenius equation allows to determine the apparent activation energy for the relaxation process. This energy is in good agreement with values from literature regarding macro DMA investigations.Future works will be devoted to test this method on softer polymers since it seems that nano-DMA overestimated the complex modulus by a factor two [2] when the modulus is of the order of MPa

Identification de paramètres de lois de comportement hyper-élastiques par indentation instrumentée d’élastomères

Les présents travaux étudient l’identification de paramètres de lois de comportement hyper-élastiques à partird’essais d’indentation instrumentée. Deux matériaux élastomères sont caractérisés à différentes échelles, parindentation, ainsi qu’au travers d’essais macroscopiques homogènes. Une approche numérique de réduction demodèle est appliquée pour identifier les paramètres de lois de comportement à partir des essais d’indentation.Les résultats obtenus sont alors confrontés aux paramètres de la loi classiquement déterminés à partir des essaismacroscopiques. Les protocoles choisis ont permis de contourner certains verrous expérimentaux amenant à desrésultats représentatifs du comportement macroscopique observé

Identification de paramètres de lois hyperélastiques d'un silicone chargé par indentation instrumentée

Particle-filled elastomers are widely used in industries ranging from civil engineering to aeronautics and automotive. The specific phenomena of the mechanical behaviour of these materials are well known at the macro scale (hyperelasticity, viscoelasticity, Mullins effect). Indentation is therefore a well-suited method for studying them at lower scales. However, the indentation of polymers and therefore elastomers leads to experimental difficulties (surface state, adhesion). As a results, a combination of experimental and numerical studies is required. To that end, O. Ezzaamari et al. [1] show the possibility to use the entire indentation curve to identify parameters of hyperelastic constitutive models using model reduction. The main purpose of this work is to study the actual application of this identification methodology to filled Polydimethylsiloxane rubber. Experimental tests for identification purposes are carried out using spherical indentation. The induced stress state is studied numerically in order to compare the results with equivalent homogeneous macroscopic tests. Coupling spherical indentation and identification by model reduction allows to characterize the mechanical behaviour of RTV. However, a complete identification of the Mooney-Rivlin constitutive model parameters is not possible. This may be explain by the fact that spherical indentation reaches a low strain level (≈ 20%), so the Mooney-Rivlin model is applied in its low operating limit, where a simpler model such as Neo-Hooke would be adequate. Furthermore, another possible explanation is that spherical indentation does not show any real triaxiality in the stress state. The study of different tip shapes that would increase the triaxiality and the strain level would lead to better identification results. The main perspective of this work is to study visco-hyperelastic material through static and dynamic tests. The authors gratefully acknowledge the CEA le Ripault, Centre d'études du Ripault, 37260 Monts, France, for supplying the materials

Relationship between polymorphism and mechanical response of semi-crystalline polyamide films: case of PA11 and PA6

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