Phenotypic differences between dermal fibroblasts from different body sites determine their responses to tension and TGFβ1

BACKGROUND: Wounds in the nonglabrous skin of keloid-prone individuals tend to cause large disordered accumulations of collagen which extend beyond the original margins of the wound. In addition to abnormalities in keloid fibroblasts, comparison of dermal fibroblasts derived from nonwounded glabrous or nonglabrous skin revealed differences that may account for the observed location of keloids. METHODS: Fibroblast apoptosis and the cellular content of α-smooth-muscle actin, TGFβ1 receptorII and ED-A fibronectin were estimated by FACS analysis. The effects of TGFβ1 and serum were examined. RESULTS: In monolayer cultures non-glabrous fibroblasts were slower growing, had higher granularity and accumulated more α-smooth-muscle actin than fibroblasts from glabrous tissues. Keloid fibroblasts had the highest level of α-smooth-muscle actin in parallel with their expression level of ED-A fibronectin. TGFβ1 positively regulated α-smooth-muscle actin expression in all fibroblast cultures, although its effects on apoptosis in fibroblasts from glabrous and non-glabrous tissues were found to differ. The presence of collagen I in the ECM resulted in reduction of α-smooth-muscle actin. A considerable percentage of the apoptotic fibroblasts in attached gels were α-smooth-muscle actin positive. The extent of apoptosis correlated positively with increased cell and matrix relaxation. TGFβ1 was unable to overcome this apoptotic effect of matrix relaxation. CONCLUSION: The presence of myofibroblasts and the apoptosis level can be regulated by both TGFβ1 and by the extracellular matrix. However, reduction of tension in the matrix is the critical determinant. This predicts that the tension in the wound bed determines the type of scar at different body sites

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Dynamique intermittente du plankton : analyse de la dynamique multi-échelles en utilisant la décomposition modale empirique

Fortement influencé par la température et demandant de la lumière pour sa croissance, le dévelop­ pement du phytoplancton (plancton végétal) a une forte composante saisonnière. L'objectif de notre étude est ici d'analyser la dynamique non-linéaire et multi-échelle du phytoplancton en milieu côtier. La base de données utilisée dans cette étude provient d'un système automatisé en point fixe, appelé MAREL Carnot, géré par IFREMER. Ce système, localisé à la sortie de la rade du port de Boulogne-sur-Mer, enregistre plus de 15 paramètres physico­ chimiques avec une périodicité de 20 minutes. Nous utilisons ici les données enregistrées entre 2004 et 2011. Différents résultats sont obtenus concernant la dynamique et les statistiques des efflorescences. D'un côté, la fonction de densité de probabilités (PDF) réalisée sur l'ensemble des données de fluorescence obéit à une loi de puissance de pente -2. En considérant les PDF année par année, on met en évidence une relation de la pente hyperbolique avec les températures moyennes annuelles. En ce qui concerne la dynamique, nous utilisons la méthode EMD ( Empirical Mode Decompostion) pour estimer des spectres de puissance et étudier la dynamique multi-échelle via des lois d'échelle. On met en évidence des relations entre les pentes issues de ces spectres et la fluorescence. La méthode EMD est également utilisée pour mettre en évidence les fortes oscillations existant en période de bloom

FOLD project : experimental assessment of the efficiency of an optical fibre to detect a gaseous leak on a buried pipe

In 2015, TOTAL, AIR LIQUIDE, GRTgaz, ENGIE E&P International and INERIS were involved in a collaborative project called FOLD. Its objective was to experimentally assess the capability of an optical fibre based system to detect gaseous leaks occurring on a buried pipe. During this project, several parameters were tested in relation to the release properties (nature of gas, orifice diameter, pressure, direction), to the installation of the optical cable (offset location from the pipe, protection around the cable) and to the scanning means (interrogation distance, interrogator technology). This paper presents the experimental bench that was used during the testing campaign and some of the results obtained with the DTS (Distributed Temperature Sensing) equipment when these latter were interrogating the optical cable on short distance (less than 500 m). By analysing these results, it is already possible to give recommendations regarding the best positioning of the optical cable along the buried pipe to optimise the efficiency of the optical fibre based detection system

Long-term high frequency phytoplankton dynamics, recorded from a coastal water autonomous measurement system in the eastern English Channel

International audienceIn this paper, high frequency fluorescence fluctuations, recorded from 2004 to 2011 using an autonomous underwater monitoring system in the eastern English Channel, at 20-min time resolutions, are analyzed. Annual blooms are superposed to multiscale fluctuations. The probability density function (pdf) of the fluorescence time series obeys a power law with slope −2. The pdf for annual portions also obeys power laws, with slopes related to the annual average. Empirical mode decomposition (EMD) is used to study the dynamics and display the power spectrum, which is different from the temperature power spectrum. EMD is also used to extract a trend and isolate the blooms from the high frequency dynamics

Blooms de Phaeocystis sur la Côte d'Opale: investigations historiques, in Du naturalisme à l'écologie, edité par F.G. Schmitt

Dans le cadre du projet CPER de la région Nord - Pas-de-Calais portant sur le bloom de Phaeocystis, une réflexion s'est engagée concernant les aspects historiques de ces blooms. De mémoire de chercheurs, ces blooms apparaissent depuis les années 1980, et même sans doute dès la fin des années 1970, de façon récurrente et marquée sur la Côte d'Opale (Manche orientale). La question que nous abordons ici est de chercher à déterminer, par des études historiques, depuis quand ces blooms apparaissent dans la région considérée. Les résultats obtenus pourront servir à alimenter la réflexion concernant l'origine du phénomène et son caractère naturel ou partiellement anthropogénique. Les sources disponibles sur le sujet ne sont pas très abondantes, et il est difficile de trouver l'information. Un dépouillement systématique de la presse locale (Calais, Boulogne-sur-Mer) a été réalisé, pour des périodes portant sur l'Entre-deux-guerres, et sur l'après-Seconde Guerre mondiale. La première mention claire d'un phénomène de mousse pouvant s'identifier comme étant un bloom de Phaeocystis date de 1977. Les sources dépouillées et les résultats obtenus sont présentés. On discute également des travaux de Giard (fondateur de la Station maritime de Wimereux) à la fin du xixe siècle, et de l'absence de mention du phénomène dans les documents qu'il a publiés

Modèle pour une Traduction Automatique fidèle, le système TACTmultilingue, Projet LiSE (Linguistique et Sécurité)

International audienc

Modèle pour une Traduction Automatique fidèle, le système TACTmultilingue, Projet LiSE (Linguistique et Sécurité)

International audienc