399 research outputs found
Approche numérique des écoulements maternels dans le placenta humain
No full textDuring the pregnancy, the development and the foetal growth depend on the placental vascularization by the maternal blood. The aim of this study is to achieve a better understanding of uteroplacental circulation physiopathology, the CFD enables us to reach information, usually inaccessible for ethical reasons or species specificity. We show a first simplified approach which prouves the necessity of taking into consideration the blood rheological properties for the study of blood flows in the intervillous chamber. Numerical Modelisation of the Blood Flows in the Human Placenta’s Intervillous Space.Tout au long de la grossesse, le développement et la croissance du foetus dépendent de la vascularisation du placenta par le sang de la mère. L’objectif de ce travail est de permettre une meilleure compréhension de la physiopathologie de la circulation utéroplacentaire, l’outil numérique permettant d’atteindre des grandeurs habituellement non accessibles pour des raisons éthiques ou de spécificité d’espèce. On présente une première approche simplifiée qui démontre la nécessité de prendre en compte les propriétés rhéologiques du sang pour l'étude des écoulements sanguins dans la chambre intervilleuse.Senouillet Loïc, Dantan Philippe, Flaud Patrice, Guiffant Gérard, Tsatsaris Vassilis. Approche numérique des écoulements maternels dans le placenta humain. In: L'eau et le monde vivant. 28èmes Journées de l'Hydraulique. Congrès de la Société Hydrotechnique de France. Paris, 12 et 13 octobre 2004. 2004
Vassilis Alexakis: chemins croisés
No full textLa littérature migrante, produite par des auteurs qui ont choisi le français
comme langue d’écriture, et qui ont vécu l’expérience de la traversée des frontières et de
l’installation dans un pays autre, vient enrichir la littérature française contemporaine.
Notre propos est de comprendre, aujourd’hui, le parcours de Vassilis Alexakis, auteur
qui illustre si bien la problématique identitaire, la double appartenance culturelle et
linguistique au français et au grec.Migrant literature, produced by authors
who have chosen French as their writing language, and who have lived the experience of
crossing borders and settling in another country, enriches contemporary French
literature. Our aim is to understand, today, the journey of Vassilis Alexakis, author who
illustrates so well the problem of identity, the double cultural and linguistic affiliation to
both French and Greek.info:eu-repo/semantics/publishedVersio
Vassilis Alexakis: chemins croisés
No full textLa littérature migrante, produite par des auteurs qui ont choisi le français
comme langue d’écriture, et qui ont vécu l’expérience de la traversée des frontières et de
l’installation dans un pays autre, vient enrichir la littérature française contemporaine.
Notre propos est de comprendre, aujourd’hui, le parcours de Vassilis Alexakis, auteur
qui illustre si bien la problématique identitaire, la double appartenance culturelle et
linguistique au français et au grec.Migrant literature, produced by authors
who have chosen French as their writing language, and who have lived the experience of
crossing borders and settling in another country, enriches contemporary French
literature. Our aim is to understand, today, the journey of Vassilis Alexakis, author who
illustrates so well the problem of identity, the double cultural and linguistic affiliation to
both French and Greek.info:eu-repo/semantics/publishedVersio
The Reinvention of a Literary Space by Vassilis Alexakis.
No full textIn 2012, after a big operation on one leg, Vassilis Alexakis spends a month and a half on crutches at a hotel near the Parisian Luxembourg Garden. Just like the main character of his fourteenth and second to last novel, L’enfant grec, that he wrote then.
The author seems to have the need to talk about space. Not only in this book, but in all his books, the author offers countless spatial references. Is it because of his health condition then, or is it because of his current (and for many years already) life divided in between two beloved countries, that Vassilis Alexakis needs to constantly speak about space? Is there a link between all the physical spatial references and the existential need of knowing where he is? Does his identity depend on his spatial location?
With his literary combination of reality and fantasy, Alexakis might very well be reinventing space. His books could be the space in between, where he can freely just be: a Greek and a French author; narrator and character; in Greece or in France. A space in between just like the catacombs where we see the main character at the end of the book, depicted as the place where “la frontière entre le réel et l’imaginaire” is (page 307), or the space where he feels himself in every time he opens one of the volumes of his dear companion, the Grand Robert dictionary: “un espace qui n’appartient à aucun lieu, dépourvu d’addresse, qui flotte à la surface du temps comme le jardin de Callithéa” (page 281).
The relation between Vassilis Alexakis and space is worthy to revise in this particular novel since as its main character states, “C’est un livre sur la vie et la mort […]. Sur la santé et la maladie, […] le mouvement et l’immobilité, le geste et la parole.¨Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Comment Maternal influenza immunisation in resource-limited settings
No full textInternational audiencePregnant women and young infants are at high risk of developing severe infl uenza. 1,2 Among infants, those younger than 6 months have the highest risk of developing complications associated with infl uenza; 3 however, antiviral treatments and infl uenza vaccines are not approved in this age group. Given that infl uenza vaccines administered to pregnant women have shown a good safety profi le 4 and effi cacy to prevent infl uenza in infants younger than 6 months, 5,6 maternal immunisation seems to be an important strategy to protect both pregnant women and their infants. WHO targets seasonal infl uenza vaccination of pregnant women as a high priority. 7 Most high-income countries recommend maternal infl uenza immunisation to reduce the burden of infl uenza in the pregnant woman and her infant. 8 However, additional data are needed to support decisions about introduction of infl uenza vaccine in pregnant women in resource-limited settings. The Bill & Melinda Gates Foundation funded three large trials in South Africa, Mali, and Nepal, with the objective of increasing the evidence base for the eff ect of maternal infl uenza immunisation. 9 In The Lancet Infectious Diseases, Milagritos D Tapias and colleagues 10 report results of the trial done in Mali—a poorly-resourced country with high infant and maternal mortality. This is the largest randomised controlled trial evaluating the effi cacy, safety, and immuno genicity of trivalent inactivated infl uenza vaccine administered to third-trimester pregnant women to prevent infl uenza in infants younger than 6 months. 4193 women were immunised: 2018 with tri valent inactivated infl uenza vaccine and 2085 with conjugate quadrivalent meningococcal vaccine. Vaccine effi cacy against fi rst-episode laboratory confi rmed infl uenza in infants (the primary outcome) was 33·1% (95% CI 3·7–53·9) in infants born to women immunised at any time prepartum (intention-to-treat analysis), and 37·3% (7·6–57·8) in those born to women vaccinated at least 14 days prepartum (per-protocol analysis). Among participating women, vaccine effi cacy was 70·3% (95% CI 42·2–85·8) overall, 76·6% (28·4–94·3) in pregnant women, and 70·1% (28·0–89·1) in the post-partum period. There was no benefi cial eff ect of the trivalent inactivated infl uenza vaccine on birthweight. The technical and logistical feasibility of implementation of a new maternal immunisation programme was also shown with a high rate of recruitment among eligible women. Evidence of the effi cacy of maternal infl uenza immunisation to prevent infl uenza in infants in low-income countries from this trial is convincing and in agreement with fi ndings from the two previously reported randomised trials from Bangladesh (63% vaccine effi cacy, 95% CI 5–85) 5 and South Africa (48·8%, 11·6–70·4)
Etude des flux sanguins dans le placenta humain et influence du shear stress sur la fonction biologique du syncytiotrophoblaste
No full textLa placentation humaine est de type hémomonochoriale, le sang maternel est directement en contact avec le syncytiotrophoblaste. Les flux sanguins maternels, dans la chambre intervilleuse, exercent des forces mécaniques de cisaillement (shear stress) sur la surface microvillositaire du syncytiotrophoblaste. Les effets physiologiques du shear stress exercé par les flux sanguins sur l’endothélium vasculaire artériel et veineux ont fait l’objet de nombreux travaux scientifiques. En revanche, les effets biologiques du shear stress sur le syncytiotrophoblaste humain n’ont jamais été explorés. L’objectif de ce travail était premièrement d’évaluer les valeurs du shear stress exercé in vivo sur le syncytiotrophoblaste humain au cours des grossesses normales, puis de mettre au point un modèle de culture primaire dynamique afin de reproduire les conditions physiologique et d’étudier in vitro la réponse biologique du syncytiotrophoblaste au shear stress. En dépit d’un débit sanguin maternel intraplacentaire important, estimé entre 400 et 600 mL.min-1, le shear stress moyen exercée par le syncytiotrophoblaste est estimée entre 0.5±0.2 et 2.3±1.1 dyn.cm-2. Nos résultats montrent cependant que l’intensité du shear stress est très hétérogène tant à l’échelle de la chambre intervilleuse que de la villosité terminale. Nous avons développé un modèle de culture cellulaire dynamique en condition de flux adapté au syncytiotrophoblaste humain. Ce modèle permet d’appliquer un shear stress égal et constant sur toutes les cellules cultivées et reproductible à chaque culture primaire. Aux gammes de shear stress étudiées (1 dyn.cm-2), nous n’avons pas mis en évidence de diminution de la viabilité cellulaire ni de déclenchement des processus précoces d’apoptose en conditions dynamiques comparativement aux conditions statiques. Deux types de chambre de perfusion permettent d’étudier des réponses cellulaires au shear stress à court et long terme selon des temps d’exposition allant de 5 minutes à 24 heures. Ce modèle expérimental a permis de montrer que le syncytiotrophoblaste humain en culture primaire est mécanosensible. La réponse cellulaire à des niveaux de shear stress de 1 dyn.cm-2 est multiple selon les temps d’exposition et le niveau d’intégration étudié. Après 45 minutes de shear stress les taux d’AMP cyclique intracellulaires sont augmentés ce qui a pour effet d’activer la voie de signalisation intracellulaire PKA-CREB. Cette augmentation d’AMP cyclique est secondaire à la synthèse et la libération de prostaglandine E2 qui, par une boucle de régulation autocrine stimule l’adenylate cyclase. L’augmentation de la synthèse/libération de PGE2 est dépendante de l’augmentation rapide du calcium intracellulaire sous shear stress. L’exposition au shear stress de 24 heures stimule l’expression et la sécrétion du PlGF, un facteur de croissance indispensable à l’angiogenèse placentaire et pour l’adaptation maternelle à la grossesse sur le plan vasculaire. Nos travaux montrent que l’augmentation de l’AMPc intracellulaire et l’activation de la PKA contribuent à la phosphorylation de CREB, facteur de transcription régulant l’expression du PlGF.Human placentation is hemomonochorial, maternal blood circulates in direct contact with the syncytiotrophoblast. In the intervillous space, the maternal blood exerts frictional mechanical forces (shear stress) on the microvillous surface of the syncytiotrophoblast. Flowing blood constantly exerts a shear stress, on the endothelial cells lining blood vessel walls, and the endothelial cells respond to shear stress by changing their morphology, function, and gene expression. The effects of shear stress on the human syncytiotrophoblast and its biological functions have never been studied. The objectives of this study were (1) to determine in silico the physiological values of shear stress exerted on human syncytiotrophoblast during normal pregnancies, (2) to develop a model reproducing in vitro the shear stress on human syncytiotrophoblast and (3) to study in vitro the biological response of human syncytiotrophoblast to shear stress. The 2D numerical simulations showed that the shear stress applied to the syncytiotrophoblast is highly heterogeneous in the intervillous space. In spite of high intraplacental maternal blood flow rates (400-600mL.min-1), the estimated average values of shear stress are relatively low (0.5±0.2 to 2.3±1.1 dyn.cm-2). To study the shear stress-induced cellular responses during exposure times ranging from 5 minutes to 24 hours we have developed two dynamic cell culture models adapted to the human syncytiotrophoblast. We found no evidence of decreased cell viability or early processes of apoptosis in dynamic conditions (1 dyn.cm-2, 24h) compared to static conditions. Shear stress (1 dyn.cm-2) triggers intracellular calcium flux, which increases the synthesis and release of PGE2. The enhanced intracellular cAMP in FSS conditions was blocked by COX1/COX2 inhibitors, suggesting that the increase in PGE2 production could activate the cAMP/PKA pathway in an autocrine/paracrine fashion. FSS activates the cAMP/PKA pathway leading to upregulation of PlGF in human STB. Shear stress-induced phosphorylation of CREB and upregulation of PlGF were prevented by inhibition of PKA with H89 (3 μM). The syncytiotrophoblast of the human placenta is a mechanosenstive tissue
Evaluation of the utero-placental vascularization with the 3-dimensional power Doppler angiography technique : technical validations in the pregnant sheep model & clinical evaluations in pregnant women
No full textIntra-uterine growth retardation (IUGR) and preeclampsia (PE) are major complications of human pregnancy & are most often due to an insufficient utero-placental vascularization. Our aim was to evaluate the three-dimensional power Doppler angiography (PDA) as a new tool for the screening IUGR & PE & for the study placental function and IUGR in animal models. The correlation between 3D Doppler indices and the real blood flow within the utero-placental unit was first evaluated in the pregnant sheep model, as well as the impact of machine settings. A higher correlation degree was observed for VI and VFI (r = 0.86 and 0.82 respectively p<0.0001) than for FI (r = 0.64; p<0.0001).The interest of the technique was secondly demonstrated in a rabbit IUGR model (females treated with L-NAME).Thirdly, the predictive value of PDA as a screening test for IUGR & PE was demonstrated by conducting a prospective multicentric study in 70 low risk pregnant women (AUC 0.95, 100% NPV with a specificity of 85% for a 36.784 placental FI threshold).Retard de croissance intra-utérin (RCIU) et prééclampsie (PE) sont des complications majeures de la grossesse humaine et sont le plus souvent due à une insuffisance de vascularisation utéro-placentaire. Notre objectif était d'évaluer l’angiographie Doppler énergie tridimensionnelle (PDA) comme nouvel outil de dépistage de la PE et du RCIU et d’étude de la fonction placentaire et du RCIU sur modèles animaux. La corrélation entre les indices Doppler 3D et l'écoulement de sang réel au sein de l'unité utéro-placentaires a d'abord été évaluée sur modèle de brebis gravide, ainsi que l'impact des réglages de la machine. Un degré de corrélation plus élevé a été observé pour VI et VFI (r = 0,86 et 0,82 respectivement, p <0,0001) que pour FI (r = 0,64, p <0,0001).L'intérêt de la technique a été ensuite démontré dans un modèle de RCIU chez le lapin (femelles traitées par du L-NAME).Troisièmement, la valeur prédictive du PDA comme test de dépistage du RCIU et de la PE a été démontrée par la réalisation d'une étude prospective multicentrique chez 70 femmes enceintes à bas risque (AUC 0,95, 100% VAN avec une spécificité de 85% pour un seuil de 36.784 FI placentaire)
Vassilis Alexakis, the migrant greek child. About the reality of in-between fictional characters and literary spaces
No full textVassilis Alexakis (Athens, 1943-2021) started writing in French while living in France, he then changed to Greek language, which was followed by what resulted in a systematic practice of self-translation in both directions for most of his works. He is a very well-known author both in France and in Greece and one of the most well-known cases of contemporary literary self-translators, as well as an exponent of literary hybridity. In 2012 he was awarded the Prix de la Langue Française for the whole of his career. That same year, after an important operation on one leg, Vassilis Alexakis spent a month and a half on crutches at a hotel near the Parisian Luxembourg Garden. Just like the main character of his fourteenth and second to last novel, L’enfant grec, that he wrote then. In all his books, Alexakis seems to have the need to talk about himself but also about space. He constantly offers countless spatial references. Is it because of being out of his comfort zone then, or is it because of his (for many years already) life divided in between his two beloved countries, that Alexakis needs to constantly speak about places? Is there a link between all the geographical references and the existential need of knowing where he is? We shall explore the relationship between Vassilis Alexakis and space in this particular novel, linked to the reinvention of literary space in Alexakis’ work
L’enjeu de la traduction chez Vassilis Alexakis
No full textAp. J.-C., avant-dernier roman de l’écrivain grec francophone Vassilis Alexakis, est un livre exemplaire sur la problématique de l’autotraduction. À la différence des écrivains francophones issus de la colonisation auxquels le français a été imposé, rien ne prédisposait Alexakis à écrire dans cette langue. Quelles sont les raisons qui l’ont poussé à utiliser une langue autre que sa langue maternelle pour faire carrière? Pourquoi écrit-il dans deux langues? Aborder l’oeuvre d’Alexakis sous l’angle de ce que l’on appelle l’autotraduction ne constitue pas en soi une nouveauté. Mais il semble que l’on assiste en ce moment à un retour vers le grec, puisque Ap. J.-C. a lui aussi fait l’objet d’une écriture en grec et d’une autotraduction vers le français. Quels sont les choix opérationnels effectués par l’auteur pour camper un contexte aussi éloigné que le mont Athos, autrement dit la Sainte Montagne, dans Ap. J. -C., dans le but d’atteindre des imaginaires si différents? Après un survol des personnages et de la thématique de l’oeuvre, nous tenterons, dans un premier temps, de répondre à cette question par l’analyse thématique de son ouvrage et de soulever, dans un second temps, les problèmes socio-linguistiques et culturels qui résultent du passage d’une langue à l’autre, plus précisément de l’autotraduction.Ap. J.-C., the second most recent novel by the Greek Francophone writer Vassilis Alexakis, is an important example of the issue of self-translation. Unlike Francophone writers for whom the French language was imposed during colonization, Alexakis was not predisposed to write in French. What led him to use a language other than his mother tongue in his career? Why does he write in two languages? This is not the first time that Alexakis’ work has been analyzed through the lens of what is known as self-translation. However, we are currently witnessing Alexakis’ return to Greek, as the novel Ap. J-C. was also written in Greek and self-translated into French. What are the operational choices made by the author in such a remote context as Mount Athos, also known as the Holy Mountain, in Ap. J-C., in order to create such different imaginaries? After an overview of the novel’s characters and theme, we will first try to answer this question through a thematic analysis of his work. Secondly, we will address socio-linguistic and cultural issues that arise from passing from one language to another, specifically through self-translation
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