Human platelets and their capacity of binding viruses: Meaning and challenges?

Blood platelets are first aimed at ensuring primary hemostasis. Beyond this role, they have been acknowledged as having functions in the maintenance of the vascular arborescence and, more recently, as being also innate immune cells, devoted notably to the detection of danger signals, of which infectious ones. Platelets express pathogen recognition receptors that can sense bacterial and viral moieties. Besides, several molecules that bind epithelial or sub-endothelial molecules and, so forth, are involved in hemostasis, happen to be able to ligate viral determinants, making platelets capable of either binding viruses or even to be infected by some of them. Further, as platelets express both Fc-receptors for Ig and complement receptors, they also bind occasionally virus-Ig or virus-Ig-complement immune complexes. Interplays of viruses with platelets are very complex and viral infections often interfere with platelet number and functions. Through a few instances of viral infections, the present review aims at presenting some of the most important interactions from pathophysiological and clinical points of view, which are observed between human viruses and platelets.Fil: Chabert, Adrien. Universite Lyon 2; FranciaFil: Hamzeh Cognasse, Hind. Universite Lyon 2; FranciaFil: Pozzetto, Bruno. Universite Lyon 2; FranciaFil: Cognasse, Fabrice. Universite Lyon 2; FranciaFil: Schattner, Mirta Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Gomez, Ricardo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Garraud, Olivier. Universite Lyon 2; Franci

Modelling and simulation of blood collection systems: improvement of human resources allocation for better cost-effectiveness and reduction of candidate donor abandonment

International audienceFormal Petri net models were used to describe all relevant donor flows of the various blood collection systems; the Petri net models were converted onto discrete-event simulation models, allowing the evaluation of a large number of scenarios and configurations of blood collection systems. Quantitative models were proposed that encompassed all components of the blood collection systems, such as the donor arrival process, resource capacities and performance indicators. Appropriate experimental designs and cost-effectiveness analyses were used to determine the best configurations of human resources and donor appointment strategies

Multiple wavelengths reflectance microscopy to study the multi-physical behavior of MEMS

International audienceIn order to characterize surface chemomechanical driving micro-electro-mechanical systems (MEMS) behavior, we propose herein a method to simultaneously obtain a full kinematic field describing the surface displacement and a map of its chemical modification from optical measurements. Using a microscope, reflected intensity fields are recorded for two different illumination wavelengths. Decoupling the wavelength-independent and -dependent contributions to the measured relative intensity changes then yields the sought fields. This method is applied to the investigation of the electro-elastic coupling, providing images of both the local surface electrical charge density and the device deformation field

Default in plasma and intestinal IgA responses during acute infection by Simian Immunodeficiency Virus.

International audienceABSTRACT: BACKGROUND: Conflicting results regarding changes in mucosal IgA production or in the proportions of IgA plasma cells in the small and large intestines during HIV-infection have been previously reported. Except in individuals repeatedly exposed to HIV-1 but yet remaining uninfected, HIV-specific IgA are frequently absent in mucosal secretions from HIV-infected patients. However, little is known about the organization and functionality of mucosal B-cell follicles in acute HIV/SIV infection during which a T-dependent IgA response should have been initiated. In the present study, we evaluated changes in B-cell and T-cell subsets as well as the extent of apoptosis and class-specific plasma cells in Peyer's Patches, isolated lymphoid follicles, and lamina propria. Plasma levels of IgA, BAFF and APRIL were also determined. RESULTS: Plasma IgA level was reduced by 46 percent by 28 dpi and no IgA plasma cells were found within germinal centers of Peyer's Patches and isolated lymphoid follicles. This lack of a T-dependent IgA response occurs although germinal centers remained functional with no sign of follicular damage, but a prolonged survival of follicular CD4+ T-cells and normal generation of IgG plasma cells is observed. Whereas the average plasma BAFF level was increased by 4.5-fold and total plasma cells were 1.7 to 1.9-fold more numerous in the lamina propria, the relative proportion of IgA plasma cells in this effector site was reduced by 19 percent (duodemun) to 35 percent (Ileum) at 28 dpi. CONCLUSION: Our data provide evidence that SIV is unable to initiate a T-dependent IgA response during the acute phase of infection and favors the production of IgG (ileum) or IgM (duodenum) plasma cells at the expense of IgA plasma cells. Therefore, an early and generalized default in IgA production takes place during the acute of phase of HIV/SIV infection, which might impair not only a virus-specific antibody response but also IgA responses to other pathogens and vaccines as well. Understanding the mechanisms that impair IgA production during acute HIV/SIV infection is crucial to improve virus-specific response in mucosa and control microbial translocation

La contribution des données chiffrées à la construction d’un mythe. L’armée de l’Air « invaincue » en 1940

Les données quantitatives étant des instruments essentiels d’argumentation et de légitimation, la question du « rendement » de l’aviation française en 1940 est un sujet ancien de controverses. Techniquement, il renvoie aux nombres comparés des « victoires » aériennes remportées et des pertes de l’armée de l’Air. Mais ce débat n’est pas seulement comptable. Au travers de ces controverses, c’est finalement la représentation du rôle de l’armée de l’Air, sa contribution à la défaite ou, au contraire, son caractère « invaincu » qui se jouent, se construisent et s’argumentent. Deux phénomènes complémentaires mais de sens contraire peuvent alors être mis en évidence : d’une part, celui d’une surestimation notable du nombre des appareils ennemis présumés détruits par l’armée de l’Air ; d’autre part, celui de la sous-estimation tout aussi significative des pertes subies. Leur prise en compte conduit à une balance complètement différente des victoires et des pertes qui modifie radicalement la représentation du rôle de l’armée de l’Air en 1940.Quantitative data being essential instruments for defending and legitimizing a point of view, the question of the French Air Force’s performance in 1940 has long been a subject of controversy. Technically speaking, the efficiency of the French Air Force can be measured by comparative analysis of the number of victories won and of losses incurred. But the debate does not end there. At the heart of these controversies, the very representation of the Air Force’s role is at stake; its contribution to the defeat of 1940 or, on the contrary, its “invincibility” are being developed and defended. Two complementary yet opposing phenomena can then be highlighted: on the one hand, the largely overestimated number of enemy aircraft supposedly destroyed by the Air Force and, on the other, the equally significantly underestimated losses. Taking this into account leads to a completely different balance between victories and losses, radically changing the representation of the role of the Air Force in 1940

Anatomie et éthologie du lion (Panthera leo)

Le lion (Panthera leo) est un grand félin hors du commun tant au niveau comportemental qu'au niveau anatomique et physiologique.Il vit au sein d'un groupe dont la composition varie au cours du temps. Le noyau stable est représenté par les femelles, toutes parentes, qui restent toute leur vie dans la même troupe. Les lionceaux restent jusqu'à ce qu'ils atteignent l'âge adulte puis sont explusés et deviennent temporairement nomades. A la tête du groupe, on trouve un ou plusieurs mâles qui sont remplacés en moyenne tous les 2-3 ans. Les mâles sont chargés de surveiller et de marquer un territoire dont la taille varie d'un groupe à l'autre. Ils sont les garants de la sécurité de tous les membres de la troupe. Durant leurs brèves années de règne, ils tentent de se reproduire le plus possible pour assurer leur descendance avant d'être chassés par d'autres mâles plus jeunes. Les femelles sont chargées de la chasse et de l'éducation des lionceaux. La vie en groupe présente des avantages dans ces 2 activités. En effet, au moment de la chasse, les chances de réussite augmentent lorsqu'elles sont plusieurs et elles peuvent ainsi nourrir toute la troupe. En ce qui concerne les jeunes, ils profitent du lait des autres femelles allaitantes et des autres lionceaux, compagnons de jeu, pour leur apprentissage. En adoptant ce mode de vie particulier les lions ont su s'adapter au niveau anatomique. S'ils montrent de grandes similitudes avec les autres pantherinae, certaines modifications anatomiques et physiologiques sont liées aux comportements propres du lion

Dyes, flies, and sunny skies: photodynamic therapy and neglected tropical diseases

Photodynamic therapy, in its various applications, represents the focused combination of electromagnetic radiation, a chemical (usually a dye) capable of its absorption and conversion, and oxygen to provide cytotoxicity (cell killing). The effect has been known for over a century, and there is considerable clinical use in terms of its application to various cancers. However, the antimicrobial properties of the technology, which are considerable, have received only a lukewarm reception by healthcare providers, and the possibilities for tropical disease therapy are mainly unexplored. This is particularly vexatious given both the inexpensive nature of the photosensitisers and light sources available and the lack of conventional forward progress in widespread diseases such as leishmaniasis, trypanosomiasis, and tuberculosis in the Developing World. The following review therefore covers the use, or potential use, of the photodynamic approach in this area, mainly with reference to tropical diseases having current ‘neglected’ status according to the World Health Organisation. © 2016 The Authors. Coloration Technology © 2016 Society of Dyers and Colourist