Expo à La Piscine de Roubaix

L'article témoigne d'une expérience pédagogique menée durant le cours de Moyens d'expression en BAC3 en 2011.L'exercice proposé aux étudiant consiste dans un premier temps à synthétiser un tableau figuratif à l'aide de 6 couleurs.Ensuite, le travail de synthèse est transcrit en trois dimensions sous forme d'installation.Une sélection parmi les travaux fait l'objet d'une exposition lors de journées du patrimoine à la Piscine de Roubaix.L'objectif est de synthétiser un tableau par un travail en deux dimensions reprenant les principes de composition tout en simplifiant et géométrisant les formes et ensuite réinterprétation en trois dimensions sous la forme d'une table/maquette (80 x 205 cm) de la peinture qui transcrit la sensation spatiale "couleur" qui en émane

A Soluble Form of the Triggering Receptor Expressed on Myeloid Cells-1 Modulates the Inflammatory Response in Murine Sepsis

The triggering receptor expressed on myeloid cells (TREM)-1 is a recently discovered receptor expressed on the surface of neutrophils and a subset of monocytes. Engagement of TREM-1 has been reported to trigger the synthesis of proinflammatory cytokines in the presence of microbial products. Previously, we have identified a soluble form of TREM-1 (sTREM-1) and observed significant levels in serum samples from septic shock patients but not controls. Here, we investigated its putative role in the modulation of inflammation during sepsis. We observed that sTREM-1 was secreted by monocytes activated in vitro by LPS and in the serum of animals involved in an experimental model of septic shock. Both in vitro and in vivo, a synthetic peptide mimicking a short highly conserved domain of sTREM-1 appeared to attenuate cytokine production by human monocytes and protect septic animals from hyper-responsiveness and death. This peptide seemed to be efficient not only in preventing but also in down-modulating the deleterious effects of proinflammatory cytokines. These data suggest that in vivo modulation of TREM-1 by sTREM peptide might be a suitable therapeutic tool for the treatment of sepsis

Enhancement of autoantibody pathogenicity by viral infections in mouse models of anemia and thrombocytopenia.

Viral infections are involved in the pathogenesis of blood autoimmune diseases such as hemolytic anemia and thrombocytopenia. Although antigenic mimicry has been proposed as a major mechanism by which viruses could trigger the development of such diseases, it is not easy to understand how widely different viruses might induce these blood autoimmune diseases by this sole mechanism. In mice infected with lactate dehydrogenase-elevating virus (LDV), or mouse hepatitis virus, and treated with anti-erythrocyte or anti-platelet monoclonal autoantibodies at a dose insufficient to induce clinical disease by themselves, the infection sharply enhances the pathogenicity of autoantibodies, leading to severe anemia or thrombocytopenia. This effect is observed only with antibodies that induce disease through phagocytosis. Moreover, the phagocytic activity of macrophages from infected mice is increased and the enhancing effect of infection on autoantibody-mediated pathogenicity is strongly suppressed by treatment of mice with clodronate-containing liposomes. Finally, the disease induced by LDV after administration of autoantibodies is largely suppressed in animals deficient for gamma-interferon receptor. Together, these observations suggest that viruses may trigger autoantibody-mediated anemia or thrombocytopenia by activating macrophages through gamma-interferon production, a mechanism that may account for the pathogenic similarities of multiple infectious agents

ECG-gated C-arm computed tomography using L1 regularization

International audienceCardiac C-Arm computed tomography leads to a view-starved reconstruction problem because of electrocardiogram gating. The lack of data has to be compensated by a-priori information on the solution. While standard regularization is performed by minimizing a quadratic penalty term, recently proposed limited-view reconstruction techniques perform it by minimizing the L1-norm of the signal in a basis where it is supposed to be sparse. Although some algorithms are formulated with this generic L1-norm term, their practical implementations replace it by total variation, which leads to piecewise constant images. In this article, we investigate the benefits of using a different sparsifying basis, which can be chosen depending on the expected properties of the solution. It results in more flexibility in the reconstruction. We provide an in-depth description of the algorithm used for the minimization

Sparse reconstruction methods in x-ray CT

International audienceRecent progress in X-ray CT is contributing to the advent of new clinical applications. A common challenge for these applications is the need for new image reconstruction methods that meet tight constraints in radiation dose and geometrical limitations in the acquisition. The recent developments in sparse reconstruction methods provide a framework that permits obtaining good quality images from drastically reduced signal-to-noise-ratio and limited-view data. In this work, we present our contributions in this field. For dynamic studies (3D+Time), we explored the possibility of extending the exploitation of sparsity to the temporal dimension: a temporal operator based on modelling motion between consecutive temporal points in gated-CT and based on experimental time curves in contrast-enhanced CT. In these cases, we also exploited sparsity by using a prior image estimated from the complete acquired dataset and assessed the effect on image quality of using different sparsity operators. For limited-view CT, we evaluated total-variation regularization in different simulated limited-data scenarios from a real small animal acquisition with a cone-beam micro-CT scanner, considering different angular span and number of projections. For other emerging imaging modalities, such as spectral CT, the image reconstruction problem is nonlinear, so we explored new efficient approaches to exploit sparsity for multi-energy CT data. In conclusion, we review our approaches to challenging CT data reconstruction problems and show results that support the feasibility for new clinical applications

What to Do with the New Antibiotics?

Multidrug-resistant Gram-negative bacteria-related infections have become a real public health problem and have exposed the risk of a therapeutic impasse. In recent years, many new antibiotics have been introduced to enrich the therapeutic armamentarium. Among these new molecules, some are mainly of interest for the treatment of the multidrug-resistant infections associated with Pseudomonas aeruginosa (ceftolozane/tazobactam and imipenem/relebactam); others are for carbapenem-resistant infections associated with Enterobacterales (ceftazidime/avibactam, meropenem/vaborbactam); and finally, there are others that are effective on the majority of multidrug-resistant Gram-negative bacilli (cefiderocol). Most international guidelines recommend these new antibiotics in the treatment of microbiologically documented infections. However, given the significant morbidity and mortality of these infections, particularly in the case of inadequate therapy, it is important to consider the place of these antibiotics in probabilistic treatment. Knowledge of the risk factors for multidrug-resistant Gram-negative bacilli (local ecology, prior colonization, failure of prior antibiotic therapy, and source of infection) seems necessary in order to optimize antibiotic prescriptions. In this review, we will assess these different antibiotics according to the epidemiological data

Cardiac C-arm computed tomography using a 3D + time ROI reconstruction method with spatial and temporal regularization

International audiencePurpose: Reconstruction of the beating heart in 3D + time in the catheter laboratory using only the available C-arm system would improve diagnosis, guidance, device sizing, and outcome control for intracardiac interventions, e.g., electrophysiology, valvular disease treatment, structural or congenital heart disease. To obtain such a reconstruction, the patient's electrocardiogram (ECG) must be recorded during the acquisition and used in the reconstruction. In this paper, the authors present a 4D reconstruction method aiming to reconstruct the heart from a single sweep 10 s acquisition.Method: The authors introduce the 4D RecOnstructiOn using Spatial and TEmporal Regularization (short 4D ROOSTER) method, which reconstructs all cardiac phases at once, as a 3D + time volume. The algorithm alternates between a reconstruction step based on conjugate gradient and four regularization steps: enforcing positivity, averaging along time outside a motion mask that contains the heart and vessels, 3D spatial total variation minimization, and 1D temporal total variation minimization.Results: 4D ROOSTER recovers the different temporal representations of a moving Shepp and Logan phantom, and outperforms both ECG-gated simultaneous algebraic reconstruction technique and prior image constrained compressed sensing on a clinical case. It generates 3D + time reconstructions with sharp edges which can be used, for example, to estimate the patient's left ventricular ejection fraction.Conclusions: 4D ROOSTER can be applied for human cardiac C-arm CT, and potentially in other dynamic tomography areas. It can easily be adapted to other problems as regularization is decoupled from projection and back projection.Acknowledgement: Published by the American Association of Physicists in Medicine. The electronic version of this work can be reached by using the following link: http://dx.doi.org/10.1118/1.486021