32 research outputs found

    In situ detection of gliosis and apoptosis in the brains of young rats exposed in utero to a Wi-Fi signal

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    International audiencePregnant rats were daily whole-body exposed or sham-exposed to a Wi-Fi signal in a free-running reverberation chamber at 0, 0.08, 0.4, and 4 W/kg for 2 h during the last 2 weeks of gestation (5 days/week). Following this in utero exposure, the pups were divided into two groups and 1 group continued exposure for 5 weeks after birth. Several brain areas were examined for gliosis and apoptotic cells. Comparison among sham and exposed groups revealed no significant differences, suggesting that in utero and post-natal exposure to Wi-Fi did not damage the brains of the young rats

    Comparative study between radiofrequency-induced and muscimol-induced inhibition of cultured networks of cortical neuron

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    Previous studies have shown that spontaneously active cultured networks of cortical neuron grown planar microelectrode arrays are sensitive to radiofrequency (RF) fields and exhibit an inhibitory response more pronounced as the exposure time and power increase. To better understand the mechanism behind the observed effects, we aimed at identifying similarities and differences between the inhibitory effect of RF fields (continuous wave, 1800 MHz) to the γ-aminobutyric acid type A (GABAA) receptor agonist muscimol (MU). Inhibition of the network bursting activity in response to RF exposure became apparent at an SAR level of 28.6 W/kg and co-occurred with an elevation of the culture medium temperature of ~1°C. Exposure to RF fields preferentially inhibits bursting over spiking activity and exerts fewer constraints on neural network bursting synchrony, differentiating it from a pharmacological inhibition with MU. Network rebound excitation, a phenomenon relying on the intrinsic properties of cortical neurons, was observed following the removal of tonic hyperpolarization after washout of MU but not in response to cessation of RF exposure. This implies that hyperpolarization is not the main driving force mediating the inhibitory effects of RF fields. At the level of single neurons, network inhibition induced by MU and RF fields occurred with reduced action potential (AP) half-width. As changes in AP waveform strongly influence efficacy of synaptic transmission, the narrowing effect on AP seen under RF exposure might contribute to reducing network bursting activity. By pointing only to a partial overlap between the inhibitory hallmarks of these two forms of inhibition, our data suggest that the inhibitory mechanisms of the action of RF fields differ from the ones mediated by the activation of GABAA receptors

    In vitro differentiation of human cardiac fibroblasts into myofibroblasts: characterization using electrical impedance

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    Abstract Cardiac arrhythmias represent about 50% of the cardiovascular diseases which are the first cause of mortality in the world. Implantable medical devices play a major role for treating these arrhythmias. Nevertheless the leads induce an unwanted biological phenomenon called fibrosis. This phenomenon begins at a cellular level and is effective at a macroscopic scale causing tissue remodelling with a local modification of the active cardiac tissue. Fibrosis mechanism is complex but at the cellular level, it mainly consists in cardiac fibroblasts activation and differentiation into myofibroblasts. We developed a simplified in vitro model of cardiac fibrosis, with human cardiac fibroblasts whom differentiation into myofibroblasts was promoted with TGF-β1. Our study addresses an unreported impedance-based method for real-time monitoring of in vitro cardiac fibrosis. The objective was to study whether the differentiation of cardiac fibroblasts in myofibroblasts had a specific signature on the cell index, an impedance-based feature measured by the xCELLigence system. Primary human cardiac fibroblasts were cultured along 6 days, with or without laminin coating, to study the role of this adhesion protein in cultures long-term maintenance. The cultures were characterized in the presence or absence of TGF-β1 and we obtained a significant cell index signature specific to the human cardiac fibroblasts differentiation
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