Listeria pathogenesis and molecular virulence determinants

The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. Clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. Listeriosis can also manifest as a febrile gastroenteritis syndrome. In addition to humans, L. monocytogenes affects many vertebrate species, including birds. Listeria ivanovii, a second pathogenic species of the genus, is specific for ruminants. Our current view of the pathophysiology of listeriosis derives largely from studies with the mouse infection model. Pathogenic listeriae enter the host primarily through the intestine. The liver is thought to be their first target organ after intestinal translocation. In the liver, listeriae actively multiply until the infection is controlled by a cell-mediated immune response. This initial, subclinical step of listeriosis is thought to be common due to the frequent presence of pathogenic L. monocytogenes in food. In normal indivuals, the continual exposure to listerial antigens probably contributes to the maintenance of anti-Listeria memory T cells. However, in debilitated and immunocompromised patients, the unrestricted proliferation of listeriae in the liver may result in prolonged low-level bacteremia, leading to invasion of the preferred secondary target organs (the brain and the gravid uterus) and to overt clinical disease. L. monocytogenes and L. ivanovii are facultative intracellular parasites able to survive in macrophages and to invade a variety of normally nonphagocytic cells, such as epithelial cells, hepatocytes, and endothelial cells. In all these cell types, pathogenic listeriae go through an intracellular life cycle involving early escape from the phagocytic vacuole, rapid intracytoplasmic multiplication, bacterially induced actin-based motility, and direct spread to neighboring cells, in which they reinitiate the cycle. In this way, listeriae disseminate in host tissues sheltered from the humoral arm of the immune system. Over the last 15 years, a number of virulence factors involved in key steps of this intracellular life cycle have been identified. This review describes in detail the molecular determinants of Listeria virulence and their mechanism of action and summarizes the current knowledge on the pathophysiology of listeriosis and the cell biology and host cell responses to Listeria infection. This article provides an updated perspective of the development of our understanding of Listeria pathogenesis from the first molecular genetic analyses of virulence mechanisms reported in 1985 until the start of the genomic era of Listeria research

À propos du texte D’Al-Ghazâlî « Ayyuha L-Walad » : un exemple de dialogue entre le maître et l’élève

Introduction Al-Ghazâlî est né à Tûs (Khurâsân) en 450/1058, près de Meshed (actuellement au Nord-Est de l’Iran). Il vivra et enseignera à Bagdâd, dans l’entourage de Nizâm al-Mulk. Ce dernier, qui fut d’abord le ministre du sultan seldjoukide (dynastie d’origine turque) Arp Arslân, puis de son fils Malikshâh, lesquels régnaient sur un immense empire, allant de la Perse à l’Iraq et l’Anatolie, et incluant donc Bagdâd, pour le compte théorique du calife abbaside Al-Qâ’im, puis du calif..

Printing the Heart : confrontations between Theater and Liturgy in Seventeenth-Century France

La confrontation du théâtre et de la liturgie est un lieu commun de la pensée. Il est un motif rhétorique récurrent chez les pères de l’Église pour définir a contrario et par surenchère le bon ethos du chrétien à l’Église. Ce tour de pensée ecclésiastique, typique de la synthèse augustinienne de la rhétorique antique et du christianisme, n’est pas seulement un héritage livresque au XVIIe siècle. Il est particulièrement pertinent à la vue des enjeux auxquels est confrontée l’Église catholique : elle doit répondre aux accusations protestantes, qui traitaient la messe de farce ; le théâtre renouvelé de l’antique se rétablit grâce au soutien du pouvoir, se sédentarise et devient un divertissement régulier. Cette banalité nouvelle fait de la Comédie, aux yeux des augustiniens, le lieu d’une « représentation vive » et continuelle des passions du monde, particulièrement de l’amour et de l’honneur : le théâtre apparaît comme une liturgie inversée. Là où les pratiques de piété sont censées amoindrir les passions et nourrir la foi, le théâtre excite les passions et étouffe l’esprit de prière. La querelle de la moralité au théâtre montre non seulement une concurrence morale, mais aussi psychique et affective. Les deux représentations prétendent susciter la présence d’esprit et « toucher » le cœur, voire lui « imprimer des mouvements ». La messe est qualifiée de « représentation vive du sacrifice de la croix », pendant laquelle le fidèle doit se remémorer vivement le sacrifice christique et sa signification grâce à une lecture allégorique, et se l’appliquer à lui-même. Par la considération et l’accomplissement de cérémonies, par la vocalisation des psaumes, le fidèle est invité à produire des « actes » du cœur pour s’unir à Jésus-Christ. Ce rapport au texte comme trace à suivre, et ce rapport au corps et à la voix comme media pour s’auto-exciter, expliquent pourquoi les comédiens professionnels sont condamnés par les dévots : ils excitent en eux les passions contraires à l’Esprit saint, ils rappellent des sentiments qu’un pénitent ne pourrait pas se remémorer sans « horreur ». La « représentation » est alors conçue comme un effort de remémoration.Le rétablissement du théâtre à l’antique nécessitait un discours pour en éclairer les visées et en légitimer l’existence dans une société chrétienne et monarchique. Traduire la mimesis aristotélicienne par « représentation » plutôt que par « imitation » rendait le théâtre beaucoup plus proche de la liturgie et lui ajoutait les connotations de vue, de présence et de mémoire. Le débat entre plaire et instruire est un débat entre théâtre-divertissement et théâtre-cérémonie. Incomber au théâtre la fonction d’instruire, c’était le rapprocher d’une prédication et de la messe, car instruire, signifiait instruire chrétiennement. L’échec de sanctification du théâtre des années 1640 fit conclure à une incompatibilité du théâtre avec la folie et la modestie chrétienne, mais la possibilité d’une instruction civique par le théâtre émerge à la fin du siècle. Le théâtre participe de la construction d’une morale laïque.The confrontation between liturgy and theater is a topos of the discourses which reveal deeply-rooted issues of representation in the seventeenth century. This commonplace had been a recurrent rhetorical device in the patristic sermons, where it emphasized the differences between Christianity and paganism. It is vigorously reactivated in seventeenth-century France as the Catholic Church faces its Calvinist critics, who accuse mass of being a comedy. Profane theater becomes a regular and professional kind of entertainment in the city and at the court, thanks to the protection of the royal power. This is why it is seen by Augustinians as a recurrent “lively representation” of the values of the world, such as love and honor, which are contradictory to the celestial Christian spirit. Treatises against Comedy written by Christian zealots reveal not only a moral, but also an emotional and psychological competition between liturgical practices and theater. Both “representations” try to force the presence of the mind and to touch, or even to print, the heart. The mass is then qualified as the “lively representation” of the Passion of the Christ, during which Catholic prayers must commemorate the mystery of divine sacrifice. By considering and acting out ceremonies, by vocalizing prayers, the believer is invited to produce certain acts of the heart and to unite with Christ, applying the Christ’s sacrifice to himself. Thus, the believer can be assimilated to an existential comedian on the divine stage : he actively involves his sensibility in the imitation of the great Christian model, by entering into the spirit of the psalms. This relationship to the text as a vestige to follow, this use of the voice and the body as mediums to excite devotion, explain the condemnation of the professional comedian by the Christian zealots (dévots). Indeed, the comedian is seen as someone who excites his own passions, playing a dangerous game with his heart and reminding himself of former worldly passions which can only lessen his faith.The reestablishment of theater questions the legitimacy, the definition and the goals of this art in a Christian society. Translating mimesis by “representation” and not “imitation” brought the theater closer to the liturgy. The discourses on theater in the 1620s and 1630s show that the authors tended to see a memorial, reiterative and visual dimension in theater that was not present in Aristotle. The debates finally conclude on the definition of theater as an honest form of entertainment rather than as a living form of instruction, namely because the latter was the responsibility of predication and mass. Saint Thomas could justify theater as a way of merely releasing the mind without interesting the heart or touching the soul ; at that time, indeed, instruction meant Christian instruction. In the 1640s, to please the devout Spanish queen Anne of Austria, several playwrights did attempt to call back the theater to its former institutional position by assimilating it with religious ceremony and creating sanctified tragedies. But this attempt failed for both poetic and political reasons. The disposition of the spectators in the city was not to be instructed. The theater was finally recognized as incompatible with Christian folly and modesty, but slowly participated in the formation of a secular morality in a new civic sphere

"Tiques attention danger" (réalisation d'une vidéo à but préventif)

LYON1-BU Santé (693882101) / SudocSudocFranceF

La profession d'hygiéniste dentaire en Europe (synopsis 2005)

LYON1-BU Santé Odontologie (693882213) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

« L’Effet propre de la tragédie » de l’humanisme aux Lumières

International audienc

"El MAPEC". Una experiencia de evaluación integral desde el Programa Redes (MSAL) para la transformación de políticas públicas en salud

La ponencia presenta la experiencia de evaluación integral del curso Abordaje Integral del Modelo de Atención de Personas con Enfermedades Crónicas (MAPEC) que se lleva adelante en todas las provincias por el Programa Redes, Ministerio de Salud de la Nación. El curso, orientado a la promoción y difusión de dicho modelo de gestión y atención para su implementación en el sistema de salud, finaliza con la presentación por parte de los equipos participantes de un proyecto local a desarrollarse en centros de salud del primer nivel de atención. A fines de la evaluación, se seleccionaron cinco provincias, tomando como referencia algunas de las propuestas presentadas. A través de un abordaje cuali-cuantitativo se describieron las condiciones iniciales de cada uno de los contextos locales; se describieron y analizaron las propuestas presentadas; y finalmente, a través de entrevistas en profundidad se analizaron las apropiaciones singulares del curso, los modos de articulación con las dinámicas previas de trabajo, y los límites que cada realidad local impuso, explorando los procesos desencadenados a partir del curso. El informe que presentamos a continuación, señala la importancia de generar instancias evaluativas en los programas sociales y de promover abordajes integrales que permitan poner en diálogo diferentes perspectivas y técnicas metodológicas. Junto con lo anterior, contribuye al propósito de desarrollar investigaciones sociales que aporten a la toma de decisiones de quienes diseñan y ejecutan políticas públicas.Mesa 21: Evaluar para la transformación. Evaluación de políticas sociales en ArgentinaFacultad de Humanidades y Ciencias de la Educació

Incorporation of aluminium in calcium-silicate-hydrates

Calcium silicate hydrate (C-S-H) was synthetized at 20 degrees C to investigate the effect of aluminium uptake (Al/Si = 0-0.33) in the presence and absence of alkalis on the composition and the solubility of a C-S-H with a Ca/Si equal to 1.0. C-S-H incorporates aluminium readily resulting in the formation of C-A-S-H at Al/Si At higher Al/Si ratios, in addition to C-A-S-H, katoite and/or stratlingite are present. Aluminium is mainly taken up in the bridging position of the silica dreierketten structure, which increases the chain length. The aluminium uptake in C-S-H increases with the aqueous aluminium concentrations. The presence of potassium hydroxide leads to higher pH values, to the destabilisation of stratlingite and to higher dissolved aluminium concentrations, which favours the aluminium uptake in C-S-H. Potassium replaces partially the calcium ions on the surface and interlayer, thus leading to more negative surface charge and to shortening of chain length. (C) 2015 Elsevier Ltd. All rights reserved

NUMERICAL REPRESENTATIVE ELEMENTARY VOLUME GENERATION OF A SIMPLIFIED CEMENT PASTE AND ESTIMATION OF ITS DIFFUSIVITY AND COMPARISON WITH DEDICATED EXPERIMENTS

International audienceCementitious materials are widely used in the concepts of radioactive waste disposal facilities. During the lifetime of these disposals, those materials will undergo physicochemical degradations. To assess their impacts, reactive transport modellingisused.Reactivetransportcodesmodifythetransportpropertiesbasedonthemodelledporosityevolutionby usingArchie’slawasafeedbackbetweenporosityanddiffusiveproperties.Theselawsarenotsuitedtocementitiousmaterials, whose pore structure is complex and expands over a wide range of pore sizes. The ultimate goal of this research is about developing a microstructure-based feedback relation for the diffusive properties of complex porous structures such as cementitious ones. Therefore, we developed an algorithm designed to generate numerical microstructures representative of simplified cement pastes and performed an experimental campaign consisting of dedicated experiments. Arandom-walkalgorithmisusedtocomputetheeffectivediffusioncoefficientsofournumericalmicrostructures.This paper investigates the description of the initial numerical microstructure and how transport properties are sensitive to different microstructural features that can be controlled from the designed algorithm. Simulations both on the experimental microtomograph and the generated microstructures allow to show that our models are complete to describe the microstructure and diffusion transport property of simplified cementitious materials. Sensitivity analysis is also provided, whose results show that a simple feedback relation cannot properly describe these transport properties. This gives confidence in our approach and its future extension toward the description of cementitious material degradations

Calcium alumino-silicates hydrates (C-A-S-H) carbonation kinetics

Proceeding page 3612 de "Conference Proceedings of the 15th ICCC, Prague, 16-20 September 2019"International audienceIn this study, we intended to characterize the impact of carbonation on the main cement hydrate (C A S H) in terms of chemistry and kinetics of degradation as well as to provide a better understanding on the carbonation products’ properties. We synthetized C-A-S-H with increasing calcium content, i.e. Ca/Si ratios ranging from 0.80 to 1.40 and Al/ Si ratios of 0.05 and 0.10. Based on thermogravimetric, 27Al and 29Si magic angle spinnining nuclear magnetic resonance and x-ray diffraction preliminary results, it was observed that C-A-S-H and C-S-H generated, after carbonation, the same major and minor calcium carbonates polymorphs (vaterite and aragonite, respectively) and the same amorphous product (silica gel). For the C-S-H, the silica gel embedded the fraction of calcium not transformed in calcium carbonate and, it was also the case for C-A-S-H silica gel which incorporates also aluminium. It was also found that coupling a high aluminium content with a high calcium content, i.e. Ca/Si higher than 0.95, calcium aluminates hydrates of pentahedral and octahedral coordination (third aluminate hydrate, TAH) are produced. The pentahedral product is located in the C-A-S-H interlayers and the TAH on its surfaces. The presence of those species correlated with a lower kinetic of degradation for the C A S Hs. A proper understanding of the mechanisms involved requires further studies but from these preliminary results, the hypothesis of a CO2 access to the C-A-S-H limited by the calcium aluminates with Al in pentahedral environment and TAH seems acceptable