Review of patient-specific simulations of transcatheter aortic valve implantation

International audienceTranscatheter Aortic Valve Implantation (TAVI) accounts for one of the most promising new cardiovascular procedures. This minimally invasive technique is still at its early stage and is constantly developing thanks to imaging techniques, computer science, biomechanics and technologies of prosthesis and delivery tools. As a result, patient-specific simulation can find an exciting playground in TAVI. It canexpress its potential by providing the clinicians with powerful decision support, offering great assistance in their workflow. Through a review of the current scientific field, we try to identify the challenges and future evolutions of patient-specific simulation for TAVI. This review article is an attempt to summarize and coordinate data scattered across the literature about patient-specific biomechanical simulation for TAVI

Diffuse laser illumination for Maxwellian view Doppler holography of the retina

We describe the advantages of diffuse illumination in laser holography for ophthalmology. The presence of a diffusing element introduces an angular diversity of the optical radiation and reduces its spatial coherence, which spreads out the energy distribution of the illumination beam in the focal plane of the eyepiece. The field of view of digitally computed retinal images can easily be increased as the eyepiece can be moved closer to the cornea to obtain a Maxwellian view of the retina without compromising ocular safety. Compliance with American and European safety standards for ophthalmic devices is more easily obtained by preventing the presence of a laser hot spot observed in front of the cornea in the absence of a scattering element. Diffuse laser illumination does not introduce any adverse effects on digitally computed laser Doppler images.Comment: 9 page

Oxidative stress and immunologic responses following a dietary exposure to PAHs in Mya arenaria

<p>Abstract</p> <p>Background</p> <p>The aim of this research was to investigate oxidative stress and immune responses following a dietary polycyclic aromatic hydrocarbon (PAH) exposure in a marine bioindicator organism, the soft shell clam, <it>Mya arenaria</it>. Immune parameters in hemolymph (haemocyte number, efficiency of phagocytosis and haemocyte activity) and assessment of oxidative stress using catalase (CAT) activity and levels of malondialdehyde (MDA) performed on the digestive gland were estimated as biomarkers in clams fed in mesocosm with PAH contaminated phytoplankton. MDA levels and CAT activities were also measured <it>in situ </it>in organisms sampled in a control site (Metis Beach, Québec, Canada) as well as organisms sampled in a site receiving domestic effluents (Pointe-au-Père, Québec, Canada), to assess effects of abiotic variables related to seasonal variations and mixed contamination on the selected parameters.</p> <p>Results</p> <p>Results on immune parameters suggest that the PAHs may interfere with the maturation and/or differentiation processes of haemocytes. MDA results showed that lipid peroxidation did not occur following the exposure. The levels of CAT activity corresponded to weak antioxidant activity (no significant differences). Recovery was noted for all the immune endpoints at the end of the experiment.</p> <p>Conclusion</p> <p>Results suggest that immune parameters are early biomarkers that can efficiently detect a physiological change during a short term exposure to low concentrations of PAHs. The <it>in situ </it>survey (in the natural environment) suggested that clams from the Pointe-au-Père site did not show any oxidative stress as well as the clams contaminated in mesocosm, probably due to the low concentrations of PAHs used for this study. MDA levels increased however in organisms from Metis Beach, a response probably related to domestic effluents or parasitism.</p

Morphologie comparative des types hemocytaires chez quelques Mollusques bivalves d'interet commercial

SIGLECNRS T 57937 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Immunotixicité des nanoparticules de Cd/S, Cd/Te et d Ag sur des espèces modèles

A l'heure actuelle, l'usage des nanoparticules (NP5) est de plus en plus médiatisé. Elles sont maintenant utilisées à grande échelle dans de nombreux domaines, L objectif principal de cette thèse était donc d évaluer l immunotoxicité des NPs de Cd/S, Cd/Te et d Ag sur 4 espèces modèles: l humain, la souris, la truite arc en ciel et la moule bleue, Dans le cadre de ces travaux, nous avons défini quatre sou objectifs: 1) déterminer l impact des NPs sur différentes cellules et systèmes immunitaires 2) évaluer les facteurs influençant la toxicité des NPs; 3) identifier les atteintes mécanistiques de la réponse immunitaire 4) établir la toxicité des NPs en fonction des stress environnementaux. Les résultats du projet ont démontrés que les NPs induisent des altérations des performances du système immunitaire, selon les espèces. De plus, nous avons aussi démontré que cette toxicité était influencée par la chimie, la nature du métal la taille de la NP. Nos résultats ont aussi indiqué une action mécanistique des NPs. Des phénomènes de stress oxydatif, de production d métallothionéines, d apoptose et de nécrose ont été observés. Enfin des études in situ, en France et au Québec, ont démontré que des organismes déjà sensibilisés par leur milieu de vie sont encore plus sensibles à une exposition aux NPs. Ce projet a contribué à enrichir les connaissances sur la toxicité des NPs selon différents modèles d études. Ceci a permis d évaluer la sensïbilité de chaque espèce et les actions mécanistiques des NPs. Les résultats concemant la sensibilité des différents modéles d animaux pourront étre utilisés dans les prochaines études de risques.Actually, the usage of nanoparticles (NPs) is more and more mediatized. They are used on a large scale in numerous domains. The mail objective of this thesis was to estimate the immunotoxicity of the NPs of Cd/S, Cd/Te and of Ag on 4 model species: human, mouse, rainbow trout and blue mussel. For the project, we defined four sub-objectives: 1) determine the impact of the NPs on various cells and immune systems; 2) estimate factors influencing the toxicity of the NPs; 3) identify mechanistic achievements of the immunizing answer 4 establish the toxicity of the NPs according to environmental stress. The project results demonstrate that the NPs induced immune system performance changes, according study species. Furthermore, we also demonstrated that this toxicity was influenced by the chemistry, the nature of the metal and NPs size. Our results also indicated mechanistic impacts of NPs on immune cells. Oxydative stress phenomena, metallothioneines production, apoptosis and necrosis were observed. Finally in situ studies, in France and in Quebec, demonstrated that organisms already sensitized by their life environment are more sensitive to additional exposure of NPs. This project contributed to improve the knowledge on NPs toxicity according to different models species. This allowed to estimate the sensibility of every species on the NPs toxicity mechanism. The results concerning could be used in the future studies of risk assessment.BREST-BU Droit-Sciences-Sports (290192103) / SudocSudocFranceF

Seasonal variations of immune parameters in diploid and triploid Pacific oysters, Crassostrea gigas (Thunberg)

International audienceDuring the last two decades, knowledge of shellfish immunology has been largely improved and the immune status of bivalves can be assessed by the measurement of both cellular and humoral parameters. Previous monitoring studies which the immune status of bivalve molluscs has been assessed have demonstrated that many parameters may vary greatly among sites and seasons, suggesting that environmental and endogenous factors may affect this system. Reproduction may also interfere with the immune system. This study focuses on the seasonal variations of the immune parameters in two batches of Pacific oysters differing by their ploidy, diploid′s and triploid′s. The oysters were sampled from a French oyster farm over two reproductive periods. Selected immune parameters investigating haemocyte integrity and immunocompetency were analysed monthly by flow cytometry. Histological observations were made in gonads to discriminate gender and gametogenesis stages. Results indicate that immune parameters in both diploid and triploid oysters exhibited marked seasonal variations. Phagocytosis index was significantly low during spawning before reaching a maximum in autumn. Triploids also appeared to be less sensitive to environmental cues than diploids. Taken as a whole, alterations observed in maturing individuals corresponded to a depressed immune status in late spring, at a time corresponding to the spawning period. Furthermore, grouping by sex of ongoing gametogenesis individuals revealed uneven immune alterations among males and females. Finally, grouping sexual maturation stages showed evidence of a peculiar stressful event during early gametogenesis, perhaps under endogenous control

Validation des outils immunotoxicologiques pour l'étude des effets biologiques des contaminants chimiques en milieu marin

Les effluents industriels, agricoles et urbains, chargés en polluants divers, soumettent les écosystèmes marins côtiers à un risque écotoxicologique chronique. Depuis une vingtaine d années, es effets toxiques des polluants sur le système immunitaire ont été étudiés chez tous les groupes écologiques, notamment chez les bivalves pour caractériser ce risque dans les écosystèmes aquatiques. Pour définir un cadre opérationnel de ces outils immunotoxicologiques, il a fallu d abord étudier plusieurs questions méthodologiques. Ensuite, il convenait d étudier l impact des facteurs endogènes et environnementaux naturels sur le signal immunotoxique généré par un polluant. Dans le cadre d une collaboration franco-québécoise, un suivi bisannuel, en France (Rade de Brest), chez la moule bleue, Mytilus edulis et chez l huître creuse, Crassostrea gigas, a permis de mettre en évidence le rôle critique du sexe et du cycle reproducteur sur les variations saisonnières des paramètres immunitaires, au détriment des paramètres naturels de la colonne d eau. En parallèle, deux série d expositions in tubo de moules bleues, au Québec, à deux saisons différentes a également mis en évidence le rôle critique du sexe et du cycle reproducteur dans la mesure du signal immunotoxique des xénobiotiques, mais surtout dans la sensibilité immunotoxique. En conclusion, ces travaux ont permis de créer un cadre opérationnel d utilisation des biomarqueurs immunotoxicologiques, pour l évaluation du risque chimique dans les milieux marins côtiers. Mais ils ont également démontré l importance capitale des facteurs endogènes étudiés pour évaluer, au plus juste, le danger des substances chimiques.Industrial, agricultural, and urban sewages, loaded in various pollutants, draw a chronic ecotoxicological risk on coastal marine ecosystems. For twenty years, the toxic effects of chemicals on the immune system have been studied in ail ecological groups, especially in bivalves, to characterize that risk in aquatic ecosystems. To define an operating framework of these immunotoxicological tools, several methodological questions were addressed. Then, was studied the impact of natural endogenous and environmental factors on the immunotoxic signal emitted by a pollutant. Through a French and Canadian framework, two-year surveys n the blue mussel, Mytilus edulis and in the Pacific oyster, Crassostrea gigas, took place in France (Rade de Brest) and gave evidence of the critical role of sex and reproductive cycle on the seasonal patterns of immune parameters, despite the environmental factors of the water column. in the meantime, batches of in tubo exposures of blue mussels, in Quebec, at two different seasons, showed also the importance of sex and reproductive cycle in the measurement of the immunotoxic signal, but, most of ail, in the immunotoxic sensitivity. Finally, this research built an operating framework for the use of immunotoxicoiogical biomarkers, for chemical risk assessment in coastal marine ecosystems. Furthermore, these findings showed the dramatic role of the studied confounding factors to assess with accuracy the danger of chemical.BREST-BU Droit-Sciences-Sports (290192103) / SudocPLOUZANE-Bibl.La Pérouse (290195209) / SudocSudocFranceF

L' insuffisance aortique post-traumatique (revue de la littérature)

BREST-BU Médecine-Odontologie (290192102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

LA SCLEROSE EN PLAQUES ET LA VACCINATION CONTRE L'HEPATITE B (A PROPOS DE 14 OBSERVATIONS NANCEENNES)

NANCY1-SCD Medecine (545472101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Flow cytometric measurement of the clearance rate in the blue mussel Mytilus edulis and the development of a new individual exposure system for aquatic immunotoxicological studies

International audienceAnimals in poor health condition are not relevant biological models. The current study focused on the use of the clearance rate of Mytilus edulis to assess the gross physiological condition of individuals maintained in stressful experimental conditions. This approach was developed in a new, highly controlled experimental exposure device designed to investigate individual responses in aquatic ecotoxicological studies. Both clearance rate values and immune parameters analysis indicated that the health condition of mussels kept in 50 ml tubes for 24 h or 48 h was not altered compared to controls, while most parameters were depressed after 72 h. Moreover, this study confirms the relevance of flow cytometric for the measurement of clearance rate compared to techniques utilizing microscopy. Current results prompted us to perform further 24 h chemical exposure using this "in tubo" device