The phenotype of circulating follicular-helper T cells in patients with rheumatoid arthritis defines CD200 as a potential therapeutic target

Rheumatoid arthritis (RA) is a systemic autoimmune disease primarily affecting synovial joints in which the development of autoantibodies represents a failure of normal tolerance mechanisms, suggesting a role for follicular helper T cells (TFH) in the genesis of autoimmunity. To determine whether quantitative or qualitative abnormalities in the circulating TFH cell population exist, we analysed by flow cytometry the number and profile of these cells in 35 patients with RA and 15 matched controls. Results were correlated with patient characteristics, including the presence of autoantibodies, disease activity, and treatment with biologic agents. Circulating TFH cells from patients with RA show significantly increased expression of the immunoglobulin superfamily receptor CD200, with highest levels seen in seropositive patients (P=0.0045) and patients treated with anti-TNFα agents (P=0.0008). This occurs in the absence of any change in TFH numbers or overt bias towards Th1, Th2, or Th17 phenotypes. CD200 levels did not correlate with DAS28 scores (P=0.887). Although the number of circulating TFH cells is not altered in the blood of patients with RA, the TFH cells have a distinct phenotype. These differences associate TFH cells with the pathogenesis of RA and support the relevance of the CD200/CD200R signalling pathway as a potential therapeutic target

Les clusters ou districts industriels du domaine culturel et médiatique : revue du savoir économique et questionnement

Financé par le Ministère de la culture et de la communication, ce projet a pour objet de dresser un panorama des travaux à la fois théoriques et empiriques réalisés sur les clusters et districts industriels en général puis sur les clusters et districts culturels et médiatiques. Cette focalisation progressive vers le domaine culturel nous permettra de faire un point sur l’état des connaissances actuelles, leurs résultats, ainsi que sur les questions sans éléments de réponse et qui pourraient être des pistes de recherche à venir

Radio Detection of Cosmic Ray Air Shower by the CODALEMA Experiment

The possibilities of measuring Extremely High Energy Cosmic Rays (EHECR) by radio detection of electromagnetic pulses radiated during the development of extensive air showers in the atmosphere are investigated. We present the demonstrative CODALEMA experiment, set up at Nancay Radio-Observatory (France). The radio-decametric array has been adapted to measure radio transients in time coincidence between antennas.Comment: 4 pages, 4 figures, Proceedings of the 9th Pisa Meeting on Advanced Detectors, Isola d'Elba 2003, to be published in NIM

MPGDs in Compton imaging with liquid-xenon

The interaction of radiation with liquid xenon, inducing both scintillation and ionization signals, is of particular interest for Compton-sequences reconstruction. We report on the development and recent results of a liquid-xenon time-projection chamber, dedicated to a novel nuclear imaging technique named "3 gamma imaging". In a first prototype, the scintillation is detected by a vacuum photomultiplier tube and the charges are collected with a MICROMEGAS structure; both are fully immersed in liquid xenon. In view of the final large-area detector, and with the aim of minimizing dead-zones, we are investigating a gaseous photomultiplier for recording the UV scintillation photons. The prototype concept is presented as well as preliminary results in liquid xenon. We also present soft x-rays test results of a gaseous photomultiplier prototype made of a double Thick Gaseous Electron Multiplier (THGEM) at normal temperature and pressure conditions.Comment: presented at MPGD09, CRETE, June 2009; to be published in JINST Proceedings, PDF, 10 pages, 11 figure

Grouping or Grounding? Cultural District and Creative Cluster Management in Nantes, France

This study examines the genesis of a cultural and creative cluster (CCC) as a collection of small or very small companies. The authors use the results of a longitudinal case study of the trajectory of a CCC to reflect on the management mechanisms in CCCs based on an analysis of management tools and how they operate to encourage Grounding and/or Grouping dynamics. This six-year study of Quartier de la Creation in Nantes, France, confirms the prevailing view of a CCC as a dynamic organization. The CCC shows distinct stages, each with its own governance and managerial difficulties. It reveals challenges in shaping the role of the support organization and in identifying the competencies to be developed. The governance mechanisms and the cluster practices of some localized groupings of very small creative enterprises require a balancing of Grouping and Grounding approaches, as hybridizing is central to cluster dynamics

Autour des Equations de Maxwell

National audienceUne série de manipulations autour des équations de Maxwell est présentée. Ces travaux s'adressent aux domaines de l'électromagnétisme et de l'algèbre vectorielle dans l'enseignement de la Physique et des Sciences pour l'Ingénieur des licences sciences et technologies, classes préparatoires, écoles d'ingénieur. La problématique générale est posée, en lien étroit avec les matériels utilisés : sources de potentiel, de champ électrique et de champ magnétique, capteurs adaptés, magnétorésistance et bobines de capture, sonde de mesure gradiométrique de potentiel et de champ électrique sans contact. Une quinzaine de manipulations de travaux pratiques sont décrites à des degrés divers, attachées aux 4 équations de Maxwell. La démarche a été mise en oeuvre auprès d'étudiants de niveau L2, au travers de la moitié des manipulations décrites. L'ensemble " autour des équations de Maxwell " implique une démarche distribuée au long des cursus, avec des ressorts pédagogiques liés notamment à la récurrence de l'utilisation de concepts, outils numériques, instruments scientifiques et à leurs approfondissements successifs. Elle est ouverte sur des suites possibles à donner : pistes de recherches notamment en didactique des Sciences, et pistes de développements industriels

Transactivation of EGFR by LPS induces COX-2 expression in enterocytes

Necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal morbidity and mortality in preterm infants. NEC is characterized by an exaggerated inflammatory response to bacterial flora leading to bowel necrosis. Bacterial lipopolysaccharide (LPS) mediates inflammation through TLR4 activation and is a key molecule in the pathogenesis of NEC. However, LPS also induces cyclooxygenase-2 (COX-2), which promotes intestinal barrier restitution through stimulation of intestinal cell survival, proliferation, and migration. Epidermal growth factor receptor (EGFR) activation prevents experimental NEC and may play a critical role in LPS-stimulated COX-2 production. We hypothesized that EGFR is required for LPS induction of COX-2 expression. Our data show that inhibiting EGFR kinase activity blocks LPS-induced COX-2 expression in small intestinal epithelial cells. LPS induction of COX-2 requires Src-family kinase signaling while LPS transactivation of EGFR requires matrix metalloprotease (MMP) activity. EGFR tyrosine kinase inhibitors block LPS stimulation of mitogen-activated protein kinase ERK, suggesting an important role of the MAPK/ERK pathway in EGFR-mediated COX-2 expression. LPS stimulates proliferation of IEC-6 cells, but this stimulation is inhibited with either the EGFR kinase inhibitor AG1478, or the selective COX-2 inhibitor Celecoxib. Taken together, these data show that EGFR plays an important role in LPS-induction of COX-2 expression in enterocytes, which may be one mechanism for EGF in inhibition of NEC