Description of the projects
Version
française
Certification methods for mobile phones
Christophe Grangeat
christophe.grangeat@alcatel.fr
The aim of the sub-project 1 is to verify the validity and reproductibility of test benches for SAR measurement of mobile phones among those used by french industry. Convergence of results will be assured according to the state of the art. The results will be the basis for contributions to the evolution of standards, particularly in CENELEC TC211 and IEEE SCC34 working groups. Sub-project 1 is spread in 4 parts:
Dosimetry and exposure systems
Joe Wiart
joe.wiart@rd.francetelecom.fr
The quality of the biomedical research depends partially on the quality
of the dosimetry. As it has been pointed out in the WHO report [1], the
dosimetry of the animal exposure system must be well defined. This is the
objective of subproject 2 of the RNRT project COMOBIO. Many exposure systems
have been built to analyse the health impact of radiofrequency fields.
Within the COMOBIO project, the "head-only" exposure system which has been
chosen is a loop antenna located close to the head of the animal. This
system allows a local exposition, and close to the head only the brain
tissues are exposed. Moreover these system are based on printed antenna
which easy to built and adapt to experimental conditions. In a first phase
the objective of this project is to analyse the field induce by the loop
antenna. Simulations and measurements will be carried out and compared.
After that using a non homogeneous rat model the E field and SAR will be
estimated in the head and in particular in the brain. The objective is
also to adapt this system to small animal such as mouse. The second part
of this study is dedicated to the estimation of the field induced by the
loop antenna in the
inner ear of a guinea pig. MRI and segmentation of the inner
ear of a guinea pig will be performed and used to calculate the E field.
Validation will be carried out using temperature measurement.
[1] Research Coordination Committee meeting on Electromagnetic Fields
4 5
Dec 1997 WHO « Low level exposure to radiofrequency Electromagnetic
Fields
Health Effects and Research Needs » p 8
Gérard Faucon, Jean-Louis Coatrieux
gerard.faucon@univ-rennes1.fr
Influence of radio frequency fields on human cerebral activity.
The aim of this sub-project is to determine the influence of radio frequency fields induced by a portable telephone on cerebral activity. This study needs an analysis of the behaviour of the cerebral structures located near the radiation source, such as the auditory system and temporal regions. We propose to study the influence of radio frequency fields thanks to the analysis of auditory evoked potentials. This study is carried out on healthy humans and on epileptic patients. The protocol we use allows us to compare the potentials with and without exposure. The dosimetry of this study will be carried out using both measurement and numerical methods, in order to evaluate specifically the energy deposited in tissues and to guarantee the replica of this study.
Brain metabolism and behaviour in the rat
Bruno Bontempi
b.bontempi@neurocog.u-bordeaux.fr
This project constitutes a neurobiological and behavioural approach to evaluating the possible deleterious effects of electromagnetic GSM waves on brain functioning. The aims of the project are threefold :
To map changes in regional brain functional activity and genomic expression in rats exposed to electromagnetic fields using the (14C)2-deoxyglucose brain imaging technique as a marker of cerebral metabolic activity and the transcription factor c-fos as a marker of neuronal activity. This combination of approaches will allow the identification of the brain regions which are the most sensitive to the acute and chronic effects of both 900 and 1800 MHz GSM (head only or whole-body exposure).
To select appropriate behavioural testing procedures capable of revealing any abnormal rat brain functioning following exposure to 900 and 1800 GSM. The choice of tests will be made as a function of the specific brain regions showing altered functional activity and whose behavioural roles have previously been established.
To conduct an in-depth characterisation of the eventual behavioural deficits induced by exposure to 900 and 1800 MHz GSM using a battery of tests (locomotor activity, anxiety, learning and memory performance etc.). Behavioural analyses will be combined with the use of neurobiological markers (c-fos, (14C)2-deoxyglucose) in order to better identify the nature of the neuronal mechanisms responsible for the behavioural impairments in animals exposed to electromagnetic waves.
Learning and Memory in Rodent.
Thérèse Jay & Jean-Marc Edeline
Jean-Marc.Edeline@ibaic.u-psud.fr
At the present time, only a few studies have shown that exposure to either low (50-60 Hz; Lai, 1996; Lai et al., 1998; Sienkiewicz et al., 1998) or high frequency (2450 MHz) magnetic fields (Lai et al., 1994; Wang & Lai, 1999) produce deficits in the performance of spatial learning tasks in rodents. Using the same behavioural paradigms, we intend to determine whether electromagnetic radiation used in mobile phones (GSM, 900 and 1800 MHz) affects learning and memory.
First, spatial learning will be assessed using a radial arm maze with eight baited arms. The animal has to visit four arms and then is removed from the maze. After a delay extending from 5 sec up to one hour, the rat will be placed again in the maze with only the remaining four baited arms. The rat has to enter these four arms that were not visited before. The animal performance in this task will represent a measure of working memory, i.e. memory holding information on line necessary to guide behaviour. In a second study, we plan to use a spatial navigation task where rats have to locate one baited box among 13 identical boxes distributed on a circular arena.
For all these tasks, animals will be exposed (head only exposure) during
the 45 minutes preceding each training trial. Different groups will be
used to test exposure to different SARs (1, 2, 4 W/kg). Performance of
the exposed animals will be compared to control (pseudo-exposed and «
cage control » animals) with the purpose of detecting an eventual
effect of the electromagnetic field. In future studies, performance of
animals with the same exposure will be determined in non-spatial memory
tasks as well as in attentional tasks.
Blood-brain barrier permeability and migraine in a rat model
Pierre Aubineau
Pierre.Aubineau@esa5017.u-bordeaux2.fr
Whether GSM microwaves can brake or not the blood-to-brain barrier, inducing brain oedema and inflammation, remains controversial since both positive and negative results have been published in roughly equal number. Also, epidemiologic studies did not allow to decide whether microwave exposition coul induce migraine attacks and experimental investigations on animal models are completely lacking in this topic.
The "Physiologie vasculaire" group (UMR 5017 CNRS) associated to the PIOM Laboratory have thus decided to undertake the following research:
To compare plasma protein extravasation in rats exposed or not to GSM microwaves by using sensitive techniques (immunodetection) allowing measurement of minute quantities of extravased bovine serum albumine. Arterial pressure will be monitored continuously during exposure to microwaves in order to make sure that a possible extravasation do not result from mechanical disruption of BBB due to excessive blood pressure (secondary to immobilization stress).
To use a new non-invasive animal model of cephalagia designed in our laboratory in order to compare in 4 groups (rats made sensitive to cephalagia non-exposed, rats sensitive to cephalagia exposed, controls exposed, controls non-exposed) plasma protein extravasation (inflammation) in the meninge, as well as activation of neurons in the caudal trigeminal nucleus (indicative of pain generation in the meninge).
Auditory system of the guinea pig
Jean-Marie Aran
Jean-Marie.Aran@bordeaux.inserm.fr
The effects on audition have not been documented even though the ear is the first organ exposed to GSM waves. As part of the national program COMOBIO, our laboratory studies the biologic effects of GSM microwaves on audition.
Under normal utilisation conditions, the ear is exposed not only to GSM waves, but also to acoustic stimulation. Thus the study must consider this conditions because even thought GSM microwaves might not have adverse effects on the ear in silence, they could combine with the sound produced by the phone, as some studies have already reported the synergistic effects of environmental noise with ototoxic drugs.
This study has two complementary aspects:
In vivo the effects of chronic exposure to GSM microwaves are evaluated
on auditory threshold using evoked potentials technique.
The direct effects of the microwaves on the hair cells of the organ
of Corti are also studied in vitro.
In vivo study:
guinea pigs maintained in a retraining box, have one ear exposed to
900MHz GSM microwaves 1hour/day, 5day/week during 2 months.
9 groups are studied: 3 with microwaves exposure (microwaves at 1,
2 and 4W/kg), 3 with microwaves exposure plus acoustic stimulation and
3 control groups, one non-exposed group without constraint, one sham group
(sham exposition at microwaves and acoustic stimulation) and one group
exposed to acoustic stimulation alone.
Audiograms are obtained for each ear by determination of auditory evoked
potential threshold measured at the level of the inferior colliculus in
response to acoustic stimulation at frequencies of 0.5-24kHz. At each frequency,
responses are measured over a dynamic intensity range of 0-80dB. Measures
are realised by implantation of a Teflon cannula fixed on the skull. This
cannula serves as a guide for positioning the recording electrode.
Electrocochleography (eighth-nerve action potentials recorded at the
level of the round window), as well histocochleograms are realised at the
end of experimentation on the guinea pigs that showed significant threshold
elevations.
In vitro study:
the effects of GSM waves on sensory hair cells viability is studied
in rat's organs of Corti isolated at PN4 and exposed at different
powers during 1-6hour/day. Sensory hair cell bundle is labelled and
counts of intact sensory cells are performed. Cytotoxic effects of GSM
waves are also measured at level of DNA fragmentation (apoptosis precursor)
by TUNEL method.
René de Seze
rene.de-seze@ineris.fr
The aim of this project is to investigate the effects of radiofrequency electromagnetic fields (RF) on the central nervous system (CNS) of the rat. More precisely, we study how the RF could affect levels of neurotransmitters (NT) and NT receptor activities in the rat brain.
The effects on the NT levels are examined by immunohistochemistry on brain slices. An image analysis software coupled with an optical microscope allows the localisation of NT in the CNS and the semi-quantification of variations in concentration. The following parameters are measured to reflect NT levels: optical density (O.D.), area and number of immunoreactive cells in the analysed field. A first study looks at the effects of RF on GABA (main inhibitory NT in the CNS) in the cerebellum. The technical approach used allows the analysis of the three cerebellum cell layers: molecular, Purkinje cells and granular. Experiments are being performed on rats exposed to RF at different specific absorption rates (SAR) of up to 32 W/kg for 2 hours, with either pulsed or continuous emission.
The second part of the project deals with the effects of RF on NT receptors.
In this study, the binding of specific radioligands on NT
receptors is analysed by autoradiography. In this experiment, rats
are exposed to RF at different SAR levels for 15 min. Three receptors are
studied: N-Methyl-D-Aspartate (NMDA), a subtype of glutamate receptor (main
excitatory NT in the CNS), dopamine (involved in motor functions and neuro-degenerative
syndromes) and GABA receptors.
Questions and answers of J. Moulder
European Bioelectromagnetics Association
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