256 results match your criteria: "CNRS-Universite de Bordeaux[Affiliation]"

The diversity of platelet microparticles.

Curr Opin Hematol

September 2015

aCentre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Faculté de Médecine de l'Université Laval, Québec, QC, Canada bUMR-5248-CBMN CNRS-Université de Bordeaux-IPB, Institut Universitaire de France, Allée Geoffroy Saint-Hilaire, F-33600 Pessac, France.

Purpose Of Review: Platelet microparticles are small extracellular vesicles abundant in blood. The present review will introduce the mechanisms underlying the generation of microparticles, and will describe the diverse microparticle subtypes identified to date. The most appropriate methodologies used to distinguish microparticle subtypes will be also presented.

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Lanthanum phosphate (LaPO4) nanorods dispersed in the non-aqueous solvent of ethylene glycol form a system exhibiting large intrinsic birefringence, high colloidal stability and the ability to self-organize into liquid crystalline phases. In order to probe the electro-optical response of these rod dispersions we study here the electric-field-induced birefringence, also called Kerr effect, for a concentrated isotropic liquid state with an in-plane a.c.

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Background: To show that 3D sequences with ultra-short echo times (UTEs) can generate a positive contrast whatever the magnetic field (4.7, 7 or 9.4 T) and whatever Ultra Small Particles of Iron Oxide (USPIO) concentration injected and to use it for 3D time-resolved imaging of the murine cardiovascular system with high spatial and temporal resolutions.

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A variety of signaling pathways, in particular with roles in cell fate and host defense, operate by a prion-like mechanism consisting in the formation of open-ended oligomeric signaling complexes termed signalosomes. This mechanism emerges as a novel paradigm in signal transduction. Among the proteins forming such signaling complexes are the Nod-like receptors (NLR), involved in innate immunity.

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Article Synopsis
  • hRAD51 protein plays a crucial role in restricting HIV-1 integration, both in lab experiments (in vitro) and in living organisms (in vivo).
  • Activating hRAD51 enhances its ability to inhibit HIV-1 integration, while inhibiting it leads to increased viral integration.
  • Cells with higher levels of hRAD51 before infection are more resistant to HIV-1, but activating hRAD51 during integration makes them more permissive, showing its complex role in HIV-1 replication.
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Background: Since interleukin (IL)-6 synergizes with the physiologically relevant O2 concentration in the maintenance of primitive hematopoietic stem cell (HSC) subpopulations, we hypothesized that its addition to our hypoxic response mimicking cultures (HRMCs), composed of an antioxidant-supplied serum-free xeno-free medium supplemented with the cytokines stabilizing hypoxia-inducible factor-1α and balancing HSC self-renewal and commitment, will result in a similar effect even if they are exposed to 20% O2 .

Study Design And Methods: HRMCs were exposed to 20 and 5% O2 with and without IL-6. Functional committed progenitors (colony-forming cells [CFCs]: CFU-GM, BFU-E, CFU-Mix, and CFU-Mk) were evaluated as well as the short- and long-term repopulating HSCs using in vivo NSG mice model (primary and secondary recipients, respectively).

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Mapping longitudinal relaxation times in 3D is a promising quantitative and non-invasive imaging tool to assess cardiac remodeling. Few methods are proposed in the literature allowing us to perform 3D T1 mapping. These methods often require long scan times and use a low number of 3D images to calculate T1 .

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Three-dimensional imaging of past skeletal TB: From lesion to process.

Tuberculosis (Edinb)

June 2015

De la Préhistoire à l'Actuel: Culture, Environnement, Anthropologie (PACEA - UMR 5199, CNRS - Université de Bordeaux - Ministère de la Culture et de la Communication), Allée Geoffroy Saint-Hilaire, 33615 Pessac Cedex, France; Laboratoire d'Anthropologie biologique Paul Broca, EPHE (Ecole Pratique des Hautes Etudes), Paris, France; Department of Anthropology, University of Western Ontario, Canada. Electronic address:

3D imaging has become an essential tool in the field of biological anthropology, notably for human evolution purposes. High resolution virtual 3D reconstructions of original specimens contribute to their preservation and broaden the ability for research, teaching and exchanges. Paleopathology can get substantial benefit from these methods, among others for reconstructing infectious pathological processes on ancient bones.

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Signal transduction by a fungal NOD-like receptor based on propagation of a prion amyloid fold.

PLoS Biol

February 2015

Non-self recognition in Fungi, Institut de Biochimie et de Génétique Cellulaire, UMR 5095, CNRS-Université de Bordeaux, Bordeaux, France.

In the fungus Podospora anserina, the [Het-s] prion induces programmed cell death by activating the HET-S pore-forming protein. The HET-s β-solenoid prion fold serves as a template for converting the HET-S prion-forming domain into the same fold. This conversion, in turn, activates the HET-S pore-forming domain.

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Contaminant effects on defence responses of ecologically and economically important organisms, such as the Pacific oyster Crassostrea gigas, are likely to influence their ability to resist infectious diseases, particularly at the young stages. The aim of this study was to explore the potential relationships between organic contaminants accumulated in the soft tissues of juvenile oysters, defence responses and physiological condition. Oysters were transplanted during summer and winter periods in different sites in the Marennes-Oléron Bay, the first area of oyster production in France, and in the Gironde Estuary, the biggest estuary in Occidental Europe.

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The aim of this study was to determine 1) the relevance of using the Pacific oyster Crassostrea gigas as a sentinel organism, at a juvenile stage, for polycyclic aromatic hydrocarbon (PAH) and persistent organic pollutant (polychlorobiphenyl, PCB, polybromodimethylether, PBDE, and organochlorine pesticide, OCP) contamination, 2) the potential levels of chemical organic contamination in the Marennes-Oléron Bay, and their potential sources and 3) the potential influence of physiological or environmental factors on contaminant body burdens in oysters. To this end, juvenile oysters purchased from an oyster hatchery were transplanted to a reference site, in Bouin, and to different transplantation sites in the Marennes-Oléron Bay, the first oyster production area in France, and in the Gironde Estuary, the biggest estuary in Occidental Europe. Transplantations were done during summer and winter.

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In situ helicity inversion of self-assembled nano-helices.

Chem Commun (Camb)

February 2015

Institute of Chemistry & Biology of Membranes & Nanoobjects, CNRS - Université de Bordeaux, UMR5248, 2 rue Robert Escarpit, 33607, Pessac, France.

The handedness of nanometrical helices based on surfactant assemblies was inverted when these helices were in contact with an excess solution of chiral anions with opposite enantiomers. An important difference in the kinetics of chirality inversion at the molecular level and mesoscopic level was observed.

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Diversity and variability of NOD-like receptors in fungi.

Genome Biol Evol

November 2014

Institut de Biochimie et de Génétique Cellulaire, UMR 5095, CNRS-Université de Bordeaux, France

Nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) are intracellular receptors that control innate immunity and other biotic interactions in animals and plants. NLRs have been characterized in plant and animal lineages, but in fungi, this gene family has not been systematically described. There is however previous indications of the involvement of NLR-like genes in nonself recognition and programmed cell death in fungi.

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Goal-directed behaviors are thought to be supported by a neural circuit encompassing the prefrontal cortex, the dorsomedial striatum, the amygdala, and, as more recently suggested, the limbic thalamus. Since evidence indicates that the various thalamic nuclei contribute to dissociable functions, we directly compared the functional contribution of the mediodorsal thalamus (MD) and of the anterior thalamic nuclei (ATN) in a new task assessing spatial goal-directed behavior in a cross-maze. Rats sustaining lesions of the mediodorsal or the anterior thalamus were trained to associate each of the two goal arms with a distinctive food reward.

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Earliest cranio-encephalic trauma from the Levantine Middle Palaeolithic: 3D reappraisal of the Qafzeh 11 skull, consequences of pediatric brain damage on individual life condition and social care.

PLoS One

April 2015

Unité Mixte de Recherche 5199 - De la Préhistoire à l'Actuel: Culture, Environnement et Anthropologie (PACEA), Centre National de la Recherche Scientifique (CNRS) - Université de Bordeaux, Pessac, France; Museum of Archaeology and Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

The Qafzeh site (Lower Galilee, Israel) has yielded the largest Levantine hominin collection from Middle Palaeolithic layers which were dated to circa 90-100 kyrs BP or to marine isotope stage 5b-c. Within the hominin sample, Qafzeh 11, circa 12-13 yrs old at death, presents a skull lesion previously attributed to a healed trauma. Three dimensional imaging methods allowed us to better explore this lesion which appeared as being a frontal bone depressed fracture, associated with brain damage.

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New evidence of early Neanderthal disappearance in the Iberian Peninsula.

J Hum Evol

October 2014

Estación Volcanológica de Canarias, IPNA-CSIC, Av. Astrofísico Francisco Sánchez n.° 3, 38206 La Laguna, Tenerife, Spain.

The timing of the end of the Middle Palaeolithic and the disappearance of Neanderthals continue to be strongly debated. Current chronometric evidence from different European sites pushes the end of the Middle Palaeolithic throughout the continent back to around 42 thousand years ago (ka). This has called into question some of the dates from the Iberian Peninsula, previously considered as one of the last refuge zones of the Neanderthals.

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An X-ray flexure-based microgap rheometer (X-FMR) has been designed for combining rheology and in situ small-angle X-ray scattering from the vorticity plane. The gap distance can be varied continuously from 500 μm down to several μm, which provides the unique possibility to generate a strong confinement for many complex fluids. A singular advantage of this setup is the possibility to directly probe the vorticity direction of the flow field with a microfocus X-ray beam and to probe the structural response of the fluid to combined shear and confinement in the vorticity plane.

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Proton diffusion in the hexafluorophosphoric acid clathrate hydrate.

J Phys Chem B

November 2014

Groupe de Spectroscopie Moléculaire, ISM UMR5255 CNRS - Université de Bordeaux, 351 cours de la Libération, F-33405 Talence, France.

The hexafluorophosphoric acid clathrate hydrate is known as a "super-protonic" conductor: its proton conductivity is of the order of 0.1 S/cm at ca. room temperature.

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Anomalous light absorption around subwavelength apertures in metal films.

Phys Rev Lett

May 2014

Laboratoire Photonique, Numérique et Nanosciences (LP2N), UMR 5298, CNRS-IOGS-Université de Bordeaux, Institut d'Optique d'Aquitaine, 33400 Talence, France.

In this Letter, we study the heat dissipated at metal surfaces by the electromagnetic field scattered by isolated subwavelength apertures in metal screens. In contrast to the common belief that the intensity of waves created by local sources should decrease with the distance from the sources, we reveal that the dissipated heat at the surface remains constant over a broad spatial interval. This behavior that occurs for noble metals at near infrared wavelengths is observed with nonintrusive thermoreflectance measurements and is explained with an analytical model, which underlines the intricate role played by quasicylindrical waves in the phenomenon.

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Helicenes from diarylmaleimides.

Org Lett

March 2014

Centre de Recherche Paul Pascal, CNRS & Université de Bordeaux, 115 avenue Schweitzer, 33600 Pessac, France.

Perkin condensations of arylglyoxylic acids with arylacetic acids, followed by the addition of alkylamine, yield diarylmaleimides in a one-pot procedure. The arylglyoxylic acids are obtained by arene acylation with ClCOCO2Et and reduced with NaI and hypophosphorous acid to the arylacetic acids. With 2,7-di-tert-butyl-pyren-4-yl or chrysen-6-yl as the aryl, photocyclodehydrogenation of the diarylmaleimides yields substituted helicenes which can be reduced to stable anions.

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Magnetic resonance imaging for the exploitation of bubble-enhanced heating by high-intensity focused ultrasound: a feasibility study in ex vivo liver.

Ultrasound Med Biol

May 2014

Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France; Laboratoire d'Imagerie Fonctionnelle et Moléculaire, UMR 5231 CNRS/Université de Bordeaux, Bordeaux, France.

Bubble-enhanced heating (BEH) may be exploited to improve the heating efficiency of high-intensity focused ultrasound in liver and to protect tissues located beyond the focal point. The objectives of this study, performed in ex vivo pig liver, were (i) to develop a method to determine the acoustic power threshold for induction of BEH from displacement images measured by magnetic resonance acoustic radiation force imaging (MR-ARFI), and (ii) to compare temperature distribution with MR thermometry for HIFU protocols with and without BEH. The acoustic threshold for generation of BEH was determined in ex vivo pig liver from MR-ARFI calibration curves of local tissue displacement resulting from sonication at different powers.

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Boron nitride nanotubes (BNNTs) are of intense scientific interest due to their unique physiochemical properties and prospective applications in various nanotechnologies, particularly nanobiomedicine. A critical problem hampering the application processing of BNNTs is the outer sidewall functionalization, which is primarily acquired to lead BNNTs dispersible in various solvents. Furthermore, the surface of BNNTs should be intelligently designed and precisely controlled to satisfy the specific demands of different applications.

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Paleoparasitology and paleopathology. Synergies for reconstructing the past of human infectious diseases and their pathocenosis.

Int J Paleopathol

September 2013

Laboratoire Paul Broca - Laboratoire d'Anthropologie biologique de l'Ecole Pratique des Hautes Etudes, UMR PACEA, CNRS - Université de Bordeaux, Avenue des Facultés, 33405 Talence Cedex, France. Electronic address:

Paleopathology, a discipline studying human and animal diseases of the past, developed at the beginning of the 20th century. In 1910, the father of the discipline, Sir Marc Armand Ruffer, was the first paleopathologist to describe a human parasitic disease; urinary shistosomiasis on Egyptian mummies dating from the Dynastic period. Therefore, paleopathology and paleoparasitology have the same roots.

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Dispersions of monodisperse hybrid rod-like particles by mineralization of filamentous viruses.

Langmuir

June 2013

Centre de Recherche Paul-Pascal, CNRS & Université de Bordeaux, 115 Avenue Schweitzer, F-33600 Pessac, France.

In this work, we report on the synthesis through a direct chemical approach of hybrid organic/inorganic rod-like particles with a very high aspect ratio (length/diameter) by the use of a biotemplate, the fd virus. A synthetic route is proposed based on an initial step of steric stabilization of the colloidal template by hydrophilic polymer grafting. Thanks to this polymer functionalization, the filamentous viruses are well-dispersed in solution during their mineralization by different inorganic salts, leading to suspensions of individual hybrid rod-like particles such as virus/SiO2 and virus/TiO2.

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Background: Recent analyses of de novo DNA mutations in modern humans have suggested a nuclear substitution rate that is approximately half that of previous estimates based on fossil calibration. This result has led to suggestions that major events in human evolution occurred far earlier than previously thought.

Results: Here, we use mitochondrial genome sequences from ten securely dated ancient modern humans spanning 40,000 years as calibration points for the mitochondrial clock, thus yielding a direct estimate of the mitochondrial substitution rate.

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