Éditeur(s) : HAL CCSD Institute of Electrical and Electronics Engineers
Résumé : International audience
: A new set-up for exposure of human cells in vitro at 37°C to pulse-modulated 300 MHz and 500 MHz signals of future magnetic resonance imaging (MRI) systems is designed, built up, and characterized. Two dipole antennas, specifically designed for ultra high field MRI, are used as radiating structures. The electromagnetic (EM) field distribution inside the incubator containing the cells is computed, and it is shown to be in a good agreement with measurements. The electric field at the cell level is quantified numerically. Local, 1g average, and averaged over the culture medium volume SAR are provided along with the standard deviation values for each well. Temperature increments are measured inside the culture medium during the exposure using an optical fiber thermometer. Then we identify the pulse parameters corresponding to the thermal threshold of 1°C, usually considered as a threshold for thermally-induced biological effects. For these parameters, the induction of heat shock proteins is assessed to biologically verify a potential thermal response of cells. The data demonstrate that, under the considered experimental conditions, exposure to pulsemodulated radiations emulating typical ultra high field MRI signals, corresponding to temperature increments below 1°C, does not trigger any heat shock response in human brain cells.
ISSN: 0018-9294

hal-00874329
https://hal.archives-ouvertes.fr/hal-00874329
DOI : 10.1109/TBME.2013.2270371
PUBMED : 23799680

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Much research is being carried out into indoor exposure to harmful agents. This review focused on the impact on children's health, taking a broad approach to the indoor environment and including chemical, microbial, physical and social aspects. Papers published from 2006 onwards were reviewed, with regards to scientific context. Most of publications dealt with chemical exposure. Apart from the ongoing issue of combustion by-products, most of these papers concerned semi volatile organic compounds (such as phthalates). These may be associated with neurotoxic, reprotoxic or respiratory effects and may, therefore, be of particular interest so far as children are concerned. In a lesser extent, volatile organic compounds (such as aldehydes) that have mainly respiratory effects are still studied. Assessing exposure to metals is still of concern, with increasing interest in bioaccessibility. Most of the papers on microbial exposure focused on respiratory tract infections, especially asthma linked to allergens and bio-aerosols. Physical exposure includes noise and electromagnetic fields, and articles dealt with the auditory and non auditory effects of noise. Articles on radiofrequency electromagnetic fields mainly concerned questions about non-thermal effects and papers on extremely low-frequency magnetic fields focused on the characterization of exposure. The impact of the indoor environment on children's health cannot be assessed merely by considering the effect of these different types of exposure: this review highlights new findings and also discusses the interactions between agents in indoor environments and also with social aspects.
ISSN: 1438-4639

hal-00687403
https://hal.archives-ouvertes.fr/hal-00687403
DOI : 10.1016/j.ijheh.2011.07.008
PUBMED : 21889403

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Technologies for wireless telecommunication systems using millimeter waves (MMW) will be widely deployed in the near future. Forthcoming applications in this band, especially around 60 GHz, are mainly developed for high data-rate local and body-centric telecommunications. At those frequencies, electromagnetic radiations have a very shallow penetration into biological tissues, making skin keratinocytes, and free nerve endings of the upper dermis the main targets of MMW. Only a few studies assessed the impact of MMW on neuronal cells, and none of them investigated a possible effect on neuronal differentiation. We used a neuron-like cell line (PC12), which undergoes neuronal differentiation when treated with the neuronal growth factor (NGF). PC12 cells were exposed at 60.4 GHz for 24 h, at an incident power density averaged over the cell monolayer of 10 mW/cm2. Using a large scale cell-by-cell analysis based on high-content screening microscopy approach, we assessed potential effects of MMW on PC12 neurite outgrowth and cytoskeleton protein expression. No differences were found in protein expression of the neuronal marker β3-Tubulin nor in internal expression control β-Tubulin. On the other hand, our data showed a slight increase, although insignificant, in neurite outgrowth, induced by MMW exposure. However, experimental controls demonstrated that this increase was related to heating
ISSN: 0304-3940

hal-01281481
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01281481
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01281481/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01281481/file/Effects%20of%2060-GHz%20Millimeter%20Waves%20on%20Neurite.pdf
DOI : 10.1016/j.neulet.2016.02.038