Effets sur les flux d'énergie impliqués dans l'homéostasie lors d'une exposition chronique à un champ radiofréquence chez le rat juvénile

National audienceLa balance énergétique impliquant sommeil, prise alimentaire et thermorégulation, est importante pour les organismes en croissance. Nous avons étudié les effets d'une exposition chronique aux ondes radiofréquences (RF) type antenne relais sur ces 3 fonctions physiologiques chez des rats juvéniles dans 2 environnements thermiques (24°C et 31°C). 13rats mâles Wistar âgés de 3 semaines ont été exposés continuellement pendant 5 semaines aux ondes RF (900 MHz, 1V.m-1) et comparé à 11 rats non exposés. Les résultats montrent une augmentation de la fréquence des épisodes de sommeil paradoxal à 24°C et 31°C. Les autres effets sur le sommeil dépendent de l'environnement thermique. A 31°C, la température caudale des animaux exposés est moindre que celle des contrôles suggérant une vasoconstriction exacerbée ; ce qui est confirmée avec la prazosine vasodilatatrice. De plus, la prise alimentaire est plus élevée chez les animaux exposés. La plupart des effets de l'exposition chronique aux ondes RF sur le sommeil dépendent de l'environnement thermique et les animaux exposés semblent mettre en place des processus d'économie d'énergie

Assessment of radiant temperature in a closed incubator

In closed incubators, radiative heat loss (R) which is assessed from the mean radiant temperature [Formula: see text] accounts for 40–60% of the neonate’s total heat loss. In the absence of a benchmark method to calculate [Formula: see text]—often considered to be the same as the air incubator temperature—errors could have a considerable impact on the thermal management of neonates. We compared [Formula: see text] using two conventional methods (measurement with a black-globe thermometer and a radiative “view factor” approach) and two methods based on nude thermal manikins (a simple, schematic design from Wheldon and a multisegment, anthropometric device developed in our laboratory). By taking the [Formula: see text] estimations for each method, we calculated metabolic heat production values by partitional calorimetry and then compared them with the values calculated from [Formula: see text] and [Formula: see text] measured in 13 preterm neonates. Comparisons between the calculated and measured metabolic heat production values showed that the two conventional methods and Wheldon’s manikin underestimated R, whereas when using the anthropomorphic thermal manikin, the simulated versus clinical difference was not statistically significant. In conclusion, there is a need for a safety standard for measuring [Formula: see text] in a closed incubator. This standard should also make available estimating equations for all avenues of the neonate’s heat exchange considering the metabolic heat production and the modifying influence of the thermal insulation provided by the diaper and by the mattress. Although thermal manikins appear to be particularly appropriate for measuring [Formula: see text], the current lack of standardized procedures limits their widespread use

Induction of galectin-1 expression by HTLV-I Tax and its impact on HTLV-I infectivity

© 2008 Gauthier et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

DMTs and Covid-19 severity in MS: a pooled analysis from Italy and France

We evaluated the effect of DMTs on Covid-19 severity in patients with MS, with a pooled-analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid-19 severity was assessed by multivariate ordinal-logistic models and pooled by a fixed-effect meta-analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti-CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39–3.02, p < 0.001) with Covid-19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18–0.99, p = 0.047). This pooled-analysis confirms an increased risk of severe Covid-19 in patients on anti-CD20 therapies and supports the protective role of interferon

L’exposition aux radiofréquences considérée comme une astreinte: Réponses physiologiques d’adaptation ou d’évitement du rat juvénile exposé aux ondes radiofréquences type antenne relais

Il est bien connu que l’exposition de longue durée à des contraintes environnementales peut induire une adaptation qui a pour but d’accroître la résistance de l’organisme. Si cela a été démontré pour certaines d’entre elles, aucune étude n’a, jusqu’à présent, porté sur l’adaptation à une exposition prolongée aux ondes radiofréquences (RF). L’objectif principal du projet "EVIREF" était de déterminer si une exposition chronique aux ondes radiofréquences type antenne relais (situation couramment rencontrée dans la population) de faible intensité (n’entraînant pas d’échauffement des tissus) était perçue par l’organisme

Browning of white adipose tissue after repeated low power RF exposure

International audienceAfter a repeated exposure to low powerradiofrequency electromagnetic fields (RF), miceand rats showed thermoregulatory changesmimicking reactions to cold. Body temperaturepatterns in mice, measured by telemetrytransmitters, changed synchronously with the RFexposure periods after 3 days. The shown episodesof quick temperature increase lead us to considerbrown adipose tissue as an effector, but inguinalwhite adipose tissue was also analyzed forcomparison. Strikingly, like responses to coldstimuli, both exposed rats and mice showedchanges in the morphology of white and brownadipocytes. Exposure also led to a larger plasmaconcentration of non-esterified fatty acids (NEFA), amarker of lipolysis in non-shivering thermogenesis