Publications by authors named "Mathieu Richard"

Wave-like beating of eukaryotic cilia and flagella-threadlike protrusions found in many cells and microorganisms-is a classic example of spontaneous mechanical oscillations in biology. This type of self-organized active matter raises the question of the coordination mechanism between molecular motor activity and cytoskeletal filament bending. Here we show that in the presence of myosin motors, polymerizing actin filaments self-assemble into polar bundles that exhibit wave-like beating.

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Cytoskeletal filaments assemble into dense parallel, antiparallel, or disordered networks, providing a complex environment for active cargo transport and positioning by molecular motors. The interplay between the network architecture and intrinsic motor properties clearly affects transport properties but remains poorly understood. Here, by using surface micropatterns of actin polymerization, we investigate stochastic transport properties of colloidal beads in antiparallel networks of overlapping actin filaments.

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Background: Although exclusively secular approaches to xenotransplantation are methodologically necessary to establish a fundamental verdict on its theoretical ethical acceptability, it is nevertheless pragmatically appropriate to take into account specifically religious positions, as religion is a factor relevant to societal acceptability. Apart from the aspect of societal acceptability, Jewish bioethics, like other religiously embedded ethics, may enrich the broader ethical discourse on xenotransplantation, as some of its principles-pikuach nefesh being the most prominent one-are plausible even in the framework of secular ethics.

Methods: This paper first explores concepts of normativity in Jewish ethics before identifying specific ethical issues in Jewish bioethics and possible resolutions offered within the framework of Jewish ethics, and then finally examine the implications for the broader debate on xenotransplantation.

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Accurate measurement of the endogenous estrogens, estrone (E1) and estradiol (E2), is important in the clinical diagnosis and monitoring of multiple disorders. Typically, given the efficacy and low cost, radioimmunoassays (RIA) and enzyme-linked immunoassays (EIA) are used to quantify these hormones in biological samples. Unfortunately, at low levels these assays lack the necessary sensitivity and specificity for diagnosis of certain disorders in adult and pediatric endocrinology and oncology.

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Dietary ubiquinone (Coenzyme Q10) is considered an essential co-factor in the mitochondrial respiratory chain responsible for oxidative phosphorylation. This oil-soluble vitamin-like substance is mobile in cellular membranes and plays a unique role in the electron transport chain (ETC). Coenzyme Q10 (CoQ10) is present in most eukaryotic cells and functions as an electron carrier and an antioxidant.

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Background: Unlike allotransplantation, reflections on xenotransplantation are infrequent in theological literature. However, xenotransplantation poses questions specifically concerning ethical and theological aspects that are imperative to address, such as personal identity between the poles of body, soul, and mind, the relationship between humans and animals, as well as challenges regarding specific issues of medical and social ethics.

Method: This study summarizes the lectures of the symposium on "Xenotransplantation-a challenge to theological ethics," which took place in Munich from September 30 until October 2, 2013, and analyses the implications of xenotransplantation from the perspectives of Christian theological ethics, biblical theology, and systematic theology.

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The compound 2,6-diisopropylphenol (Propofol, PRF) is widely used for inducing general anesthesia, but the mechanism of PRF action remains relatively poorly understood at the molecular level. This work examines the possibility that a potential mode of action of PRF is to modulate the lipid order in target membranes. The effect on monolayers and bilayers of dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC) was probed using Langmuir monolayer isotherms, differential scanning calorimetry (DSC), isothermal titration calorimetry (ITC) and molecular dynamics (MD) simulations.

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Article Synopsis
  • * The study investigates the role of caveolin-1, a protein important for monocyte function, finding that its deficiency in SSc monocytes leads to increased migration due to overexpression of CXCR4, a receptor for the chemokine CXCL12.
  • * Treatment with a caveolin-1 restoring peptide reduces excessive migration of SSc monocytes and fibrocyte accumulation in lung tissue, suggesting that enhancing caveolin-1 function could be a therapeutic strategy for managing ILD in scleroderma
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Objectives: Reduced caveolin-1 levels in lung fibroblasts from patients with scleroderma and the lungs of bleomycin-treated mice promote collagen overexpression and lung fibrosis. This study was undertaken to determine whether caveolin-1 is deficient in leucocytes from bleomycin-treated mice and patients with scleroderma and to examine the consequences of this deficiency and its reversal.

Methods: Mice or cells received the caveolin-1 scaffolding domain (CSD) peptide to reverse the pathological effects of reduced caveolin-1 expression.

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Lung fibrosis involves the overexpression of ECM proteins, primarily collagen, by alpha-smooth muscle actin (ASMA)-positive cells. Caveolin-1 is a master regulator of collagen expression by cultured lung fibroblasts and of lung fibrosis in vivo. A peptide equivalent to the caveolin-1 scaffolding domain (CSD peptide) inhibits collagen and tenascin-C expression by normal lung fibroblasts (NLF) and fibroblasts from the fibrotic lungs of scleroderma patients (SLF).

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We show in this paper how simple considerations about bio-arrays images lead to a peak segmentation allowing the genes activity analysis. Bio-arrays images have a particular structure and the aim of the paper is to present a mathematical method allowing their automatic processing. The differential geometry approach used here can be also employed for other types of images presenting grey level peaks corresponding to a functional activity or to a chemical concentration.

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