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Brain tumour growth in rats exposed to electromagnetic fields used in wireless cellular communication

Persson, Bertil R LU ; Malmgren, Lars LU ; Brun, Arne LU and Salford, Leif LU (2014) In Acta Scientiarum Lundensia 2014(001). p.1-23
Abstract
In 1996 there was no convincing laboratory evidence that EMFs used in wireless communication could cause tumour promotion at non-thermal exposure levels. Therefore we then performed a study of the effects from exposure to such electromagnetic fields in the rat brain glioma model we were using in our research for brain tumour therapy. By stereotaxic technique rat glioma cells (RG2 or N32) were injected into the head of the right caudate nucleus in 154 pairs of Fischer 344 rats in both exposed and matched controls. Starting on day 5 after inoculation, the animals were exposed for 7 hours a day, 5 days a week during 2 - 3 weeks. Rats of both sexes were exposed to electromagnetic fields in the microwaves frequency range 915 MHz both as... (More)
In 1996 there was no convincing laboratory evidence that EMFs used in wireless communication could cause tumour promotion at non-thermal exposure levels. Therefore we then performed a study of the effects from exposure to such electromagnetic fields in the rat brain glioma model we were using in our research for brain tumour therapy. By stereotaxic technique rat glioma cells (RG2 or N32) were injected into the head of the right caudate nucleus in 154 pairs of Fischer 344 rats in both exposed and matched controls. Starting on day 5 after inoculation, the animals were exposed for 7 hours a day, 5 days a week during 2 - 3 weeks. Rats of both sexes were exposed to electromagnetic fields in the microwaves frequency range 915 MHz both as continuous waves (1 W), and as pulse-modulated at 4, 8, 16 and 217 Hz in 0.57 ms long pulses and 50 Hz in 6.67 ms pulses, all with a maximum power amplitude of 2 W per pulse. The animals were kept un-anaesthetized in well-ventilated TEM cells during 7 hours a day for 5 days a week for 2-3 weeks. Their matched controls were kept in identical TEM cells without EMF exposure. At the end of the exposure period the rat brains were examined histopathologically. The tumour size was measured with a calliper and the volume estimated as an ellipsoid.

Our study of the 154 matched pairs of rats did not show any significant difference in tumour volume between animals exposed to 915 MHz microwaves, and those not exposed. Thus our results did not support that daily exposure to EMF promotes tumour growth when given from the fifth day after the start of tumour growth in the rat brain until the sacrifice of the animal 16 days later.

In the present review our results published 1997 have been re-evaluated in terms of SAR dependence of tumour volume observed ratio (exposed / control). We thus surprisingly found that the shape of tumour volume-OR versus SAR response was of bath-tube pattern, similar to that found in our parallel studies of albumin leakage through the blood-brain barrier. Since the SAR varies between most other animal studies reviewed and human epidemiological studies this SAR dependence might explain the controversy in rendering the results. (Less)
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organization
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Contribution to journal
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published
subject
keywords
Brain tumour, RG2, N32, Fischer rats, electromagnetic fields 915 MHz, CW, pulse modulated: 4, 8, 16, 50, 217 Hz, SAR.
in
Acta Scientiarum Lundensia
volume
2014
issue
001
pages
1 - 23
publisher
Bertil RR Persson, Medical Radiation Physics, 22185 Lund, Sweden
ISSN
1651-5013
language
English
LU publication?
yes
id
05c1319d-fb4a-42a2-862d-e932d5a44d5a (old id 8261194)
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https://www.researchgate.net/profile/Bertil_Persson
date added to LUP
2015-12-14 09:30:47
date last changed
2016-04-16 01:30:50
@article{05c1319d-fb4a-42a2-862d-e932d5a44d5a,
  abstract     = {In 1996 there was no convincing laboratory evidence that EMFs used in wireless communication could cause tumour promotion at non-thermal exposure levels. Therefore we then performed a study of the effects from exposure to such electromagnetic fields in the rat brain glioma model we were using in our research for brain tumour therapy. By stereotaxic technique rat glioma cells (RG2 or N32) were injected into the head of the right caudate nucleus in 154 pairs of Fischer 344 rats in both exposed and matched controls. Starting on day 5 after inoculation, the animals were exposed for 7 hours a day, 5 days a week during 2 - 3 weeks. Rats of both sexes were exposed to electromagnetic fields in the microwaves frequency range 915 MHz both as continuous waves (1 W), and as pulse-modulated at 4, 8, 16 and 217 Hz in 0.57 ms long pulses and 50 Hz in 6.67 ms pulses, all with a maximum power amplitude of 2 W per pulse. The animals were kept un-anaesthetized in well-ventilated TEM cells during 7 hours a day for 5 days a week for 2-3 weeks. Their matched controls were kept in identical TEM cells without EMF exposure. At the end of the exposure period the rat brains were examined histopathologically. The tumour size was measured with a calliper and the volume estimated as an ellipsoid.<br/><br>
 Our study of the 154 matched pairs of rats did not show any significant difference in tumour volume between animals exposed to 915 MHz microwaves, and those not exposed. Thus our results did not support that daily exposure to EMF promotes tumour growth when given from the fifth day after the start of tumour growth in the rat brain until the sacrifice of the animal 16 days later. <br/><br>
In the present review our results published 1997 have been re-evaluated in terms of SAR dependence of tumour volume observed ratio (exposed / control). We thus surprisingly found that the shape of tumour volume-OR versus SAR response was of bath-tube pattern, similar to that found in our parallel studies of albumin leakage through the blood-brain barrier. Since the SAR varies between most other animal studies reviewed and human epidemiological studies this SAR dependence might explain the controversy in rendering the results.},
  author       = {Persson, Bertil R and Malmgren, Lars and Brun, Arne and Salford, Leif},
  issn         = {1651-5013},
  keyword      = {Brain tumour,RG2,N32,Fischer rats,electromagnetic fields 915 MHz,CW,pulse modulated: 4,8,16,50,217 Hz,SAR.},
  language     = {eng},
  number       = {001},
  pages        = {1--23},
  publisher    = {Bertil RR Persson, Medical Radiation Physics, 22185 Lund, Sweden},
  series       = {Acta Scientiarum Lundensia},
  title        = {Brain tumour growth in rats exposed to electromagnetic fields used in wireless cellular communication},
  volume       = {2014},
  year         = {2014},
}