Si la beauté…

« … et même belle, si la beauté est le contraire de la coquetterie et de la futilité … »L’Acacia Qu’écrirait-on, ou même aurait-on jamais commencé d’écrire sans cette effervescence et cet éblouissement qui vous ont agité et stupéfié à la lecture de quelques très rares œuvres : à l’adolescence, Au château d’Argol, un peu plus tard, La Recherche, et, dans l’été des vingt-quatre ans, passé le dernier concours, quand on pense faire enfin ses débuts dans la vie, L’Herbe, La Route des Flandres, His..

Un homme traversé par le travail

Entretien important, par sa longueur certainement, par sa teneur, surtout : si sa date – 1977 – le place deux ans après la publication de Leçon de choses, cet entretien outrepasse largement ce cadre de lecture en faisant le point sur un ensemble d’axes majeurs de la poétique simonienne ; en outre, il apparaît, notamment par sa première partie, comme une préfiguration du discours qui sera prononcé à Stockholm en 1985, au point de pouvoir se lire comme une première version de ce texte somme. Il..

NADPH oxidase activity is associated with cardiac osteopontin and pro-collagen type I expression in uremia.

International audienceCardiovascular disease is a frequent complication inducing mortality in chronic kidney disease (CKD) patients, which can be determined by both traditional risk factors and non-traditional risk factors such as malnutrition and oxidative stress. This study aimed to investigate the role of oxidative stress in uremia-induced cardiopathy in an experimental CKD model. CKD was induced in Sprague-Dawley rats by a 4-week diet supplemented in adenine, calcium and phosphorous and depleted in proteins. CKD was associated with a 3-fold increase in superoxide anion production from the NADPH oxidase in the left ventricle, but the maximal activity of mitochondrial respiratory chain complexes was not different. Although manganese mitochondrial SOD activity decreased, total SOD activity was not affected and catalase or GPx activities were increased, strengthening the major role of NADPH oxidase in superoxide anion output. Superoxide anion output was associated with enhanced expression of osteopontin (×7.7) and accumulation of pro-collagen type I (×3.7). To conclude, the increased activity of NADPH oxidase during CKD is associated with protein modifications which could activate a pathway leading to cardiac remodelling

HDL Proteome in Hemodialysis Patients: A Quantitative Nanoflow Liquid Chromatography-Tandem Mass Spectrometry Approach

Aside from a decrease in the high-density lipoprotein (HDL) cholesterol levels, qualitative abnormalities of HDL can contribute to an increase in cardiovascular (CV) risk in end-stage renal disease (ESRD) patients undergoing chronic hemodialysis (HD). Dysfunctional HDL leads to an alteration of reverse cholesterol transport and the antioxidant and anti-inflammatory properties of HDL. In this study, a quantitative proteomics approach, based on iTRAQ labeling and nanoflow liquid chromatography mass spectrometry analysis, was used to generate detailed data on HDL-associated proteins. The HDL composition was compared between seven chronic HD patients and a pool of seven healthy controls. To confirm the proteomics results, specific biochemical assays were then performed in triplicate in the 14 samples as well as 46 sex-matched independent chronic HD patients and healthy volunteers. Of the 122 proteins identified in the HDL fraction, 40 were differentially expressed between the healthy volunteers and the HD patients. These proteins are involved in many HDL functions, including lipid metabolism, the acute inflammatory response, complement activation, the regulation of lipoprotein oxidation, and metal cation homeostasis. Among the identified proteins, apolipoprotein C-II and apolipoprotein C-III were significantly increased in the HDL fraction of HD patients whereas serotransferrin was decreased. In this study, we identified new markers of potential relevance to the pathways linked to HDL dysfunction in HD. Proteomic analysis of the HDL fraction provides an efficient method to identify new and uncharacterized candidate biomarkers of CV risk in HD patients

De l’allure

Chacun en fait l’expérience à la table du libraire : pour apprécier l’allure de la prose, dans un roman, il suffit d’en lire quelques phrases, les premières et dernières, et deux ou trois autres piochées au hasard. On peut de la même façon juger des qualités littéraires d’un critique en s’attachant aux extraits qu’il lui arrive de choisir pour illustrer et justifier son enthou­siasme. « La connaissance qui leur manque à tous – écrit Flaubert à Louise Colet en septembre 1853 lorsqu’il réfléchi..

NADPH Oxidase and Oxidative Stress during Chronic Kidney Disease (modulation by HDL)

Les maladies cardiovasculaires (CV) représentent la première cause de mortalité lors de l'insuffisance rénale chronique (IRC). Cette morbidité apparat précocement lors de l'IRC et ne peut être explique par les facteurs de risque traditionnels. Le stress oxydant (SO), composante du cortège métabolique de l'IRC, représente un facteur de risque non traditionnel intriqué avec l'inflammation et la malnutrition. Le but de ce travail a été d'étudier la place du SO dans la survenue des complications CV au cours de l'IRC sur modale animal, puis de comparer le profil protéomique et la fonctionnalité des HDL in vitro entre sujets hémodialysés (HD) et témoins. Le SO au niveau CV a été étudié dans un modèle animal (adénine) d'IRC associé à la malnutrition. L'activité de la NADPH oxydase cardiaque est triple, alors que les activités des complexes de la chaîne respiratoire mitochondriale et de la SOD sont normales. Cette surproduction d'anion super oxyde est associé à une surexpression de l'ostéopontine et du pro-collagène de type I. L'étude protéomique des HDL de sujets HD et témoins a permis de préciser les anomalies qualitatives associées à la baisse des HDL induite par l'IRC. Les propriétés anti-oxydantes des HDL de ces mêmes sujets ont été étudiées in vitro sur un modèle d'oxydation des LDL au cuivre et sur un modèle cellulaire d'activation de la NADPH oxydase. En comparaison aux témoins, les HDL des sujets HD perdent leur capacité de protection des LDL contre l'oxydation. Par contre, la modulation de la NADPH oxydase sur modèle cellulaire est conservée avec les HDL de sujets HD mais serait moindre en présence d'une forte inflammation systémique. Ces résultats suggèrent que le SO est au cœur des complications cardiaques au cours de l'IRC. Parmi les mécanismes de défense endogènes, les propriétés anti-oxydantes des HDL sont en partie altérées chez le sujet HD.Cardiovascular (CV) diseases are the first cause of mortality during chronic kidney disease (CKD) and cannot only be explained by traditional risk factors (age, gender, dyslipidemia, hypertension). Oxidative stress, which has been associated with CKD, appears as a non-traditional risk factor closely interconnected with inflammation and malnutrition.This study aimed at investigating oxidative stress in CV complications in uremic rats. Then, HDL proteomic profile and in vitro functionality of HDL were compared between hemodialyzed (HD) patients and control subjects.First, an animal model of CKD associated with malnutrition, the adenine-fed rats, was set up in order to study CV oxidative stress. NADPH oxidase activity was increased three-fold, but the maximal activity of mitochondrial respiratory chain complexes and SOD were not different between groups. Superoxide anion output was associated with accumulation of osteopontin and of pro-collagen type I. In a second part, HDL proteomic study from HD and control subjects was performed to characterize qualitative modifications associated with the decrease in HDL observed in CKD. HDL anti-oxidative activities from these subjects were studied in vitro in a model of copper-induced LDL oxidation and in a cellular model of NADPH oxidase activation. Compared to control, HDL from HD patients failed to protect LDL oxidation. By contrast, HDL modulation of NADPH activity is maintained in HD patients but could be impaired by elevated inflammation.These results suggest that oxidative stress is a key event in cardiac complications during CKD. Among protective endogenous mechanisms, HDL anti-oxidative properties could be impaired in HD patients.MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Integrative Taxonomy of the Pavlovophyceae (Haptophyta): A Reassessment

International audienceThe Pavlovophyceae (Haptophyta) contains four genera (Pavlova, Diacronema, Exanthemachrysis and Rebecca) and only thirteen characterised species, several of which are important in ecological and economic contexts. We have constructed molecular phylogenies inferred from sequencing of ribosomal gene markers with comprehensive coverage of the described diversity, using type strains when available, together with additional cultured strains. The morphology and ultrastructure of 12 of the described species was also re-examined and the pigment signatures of many culture strains were determined. The molecular analysis revealed that sequences of all described species differed, although those of Pavlova gyrans and P. pinguis were nearly identical, these potentially forming a single cryptic species complex. Four well-delineated genetic clades were identified, one of which included species of both Pavlova and Diacronema. Unique combinations of morphological/ultrastructural characters were identified for each of these clades. The ancestral pigment signature of the Pavlovophyceae consisted of a basic set of pigments plus MV chl cPAV, the latter being entirely absent in the Pavlova + Diacronema clade and supplemented by DV chl cPAV in part of the Exanthemachrysis clade. Based on this combination of characters, we propose a taxonomic revision of the class, with transfer of several Pavlova species to an emended Diacronema genus. The evolution of the class is discussed in the context of the phylogenetic reconstruction presented. (C) 2011 Elsevier GmbH. All rights reserved