Study type: Medical/biological study (experimental study)

Lack of mutation induction with exposure to 1.5 GHz electromagnetic near fields used for cellular phones in brains of Big Blue mice med./bio.

By: Takahashi S, Inaguma S, Cho YM, Imaida K, Wang J, Fujiwara O, Shirai T
Published in: Cancer Res 2002; 62 (7): 1956-1960
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Aim of study (acc. to author)

To investigate genotoxic effects of electromagnetic fields (EMF) on the brain. To study whether mutations are caused in brain DNA by EMF exposure.

Background/further details

To examine the kind of possible mutations that are induced, mice that are transgenic for the lacI marker gene in lambda phage were used.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.5 GHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 90 min/day, 5 days/week for 2 or 4 weeks
  • power: 57 mW ("antenna output")
  • SAR: 2 W/kg average over mass (brain)
  • SAR: 0.27 W/kg average over mass (whole body)
  • SAR: 0.67 W/kg average over mass (brain)

Exposure 1

Main characteristics
Frequency 1.5 GHz
Type
Charakteristic
Exposure duration repeated daily exposure, 90 min/day, 5 days/week for 2 or 4 weeks
Modulation
Modulation type pulsed
Additional info

TDMA (Japanese PDC system)
Exposure setup
Exposure source
  • monopole
  • horizontal
Distance between exposed object and exposure source 4 mm
Chamber The signal from a signal generator was amplified and then split to individual exposure boxes, made of aluminium and covered inside with planar rubber ferrite absorber (7 mm thick, reflection loss at least 21.8 dB), except for the left-side face and roof. The roof of the box was a transparent absorber (22.5 mm thick, reflection loss 20 dB). The left-side face of the box acted as the ground for a horizontal monopole antenna.
Setup Each mouse was constrained with an acrylic holder so that its head was just 4 mm beneath the antenna element. For restricting exposure to the mouse brain, a flexible magnetic sheet with a thickness of 1 mm was used to cover the low part of the acrylic holder and shield the lower part of the mouse body.
Additional info Mice in the sham group were treated the same way but without actual exposure to EMF.
Parameters
Measurand Value Type Method Mass Remarks
power 57 mW - measured - "antenna output"
SAR 2 W/kg average over mass calculated brain -
SAR 0.27 W/kg average over mass calculated whole body -
SAR 0.67 W/kg average over mass calculated brain -
Measurement and calculation details

The results of computer simulation demonstrated that the field strength of EMF exposure in the whole brain was not uniform but varied within 10%.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

No gliosis or degenerative lesions were noted in brain tissues, and no obvious differences in Ki-67 labeling and apoptotic indices of glial cells were evident among the groups. There was no significant variation in the frequency of independent mutations in the lacI transgene in the brains. The results suggest that exposure to 1.5 GHz EMF is not mutagenic to mouse brain cells and does not create any increased hazard with regard to brain tumor development.

Study character:

Study funded by

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