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Medical/biological study (experimental study)

Nonthermal GSM Microwaves Affect Chromatin Conformation in Human Lymphocytes Similar to Heat Shock.

Published in: IEEE Trans Plasma Sci IEEE Nucl Plasma Sci Soc 2004; 32 (4): 1600-1608

Aim of study (acc. to author)

To study whether microwaves of Global System for Mobile Communication (GSM) induce changes in chromatin conformation in human lymphocytes.
Background/further details: Heat treatment (40-46°C) and treatment with the genotoxic agent camptothecin were used as positive controls.
Immortal lymphoblastoid (transformed) cell line was obtained by infection of human lymphocytes of healthy donor with EBV.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 895–915 MHz
Modulation type: pulsed
Exposure duration: continuous for 30 min or 1 h
Exposure 1
Main characteristics
Frequency 895–915 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 30 min or 1 h
Additional info The test mobile phone was programmed to use pre-set frequencies of 895, 900, 905, 910, and 915 MHz.
Modulation
Modulation type pulsed
Pulse width 577 µs
Duty cycle 12.5 %
Additional info Standard GSM modulation with waiting time of 4039 µs (seven time slots) between pulses. Voice modulation was not applied, and discontinuous transmission mode (DTX) was off.
Exposure setup
Exposure source
Chamber output of the phone connected by coaxial cable to the TEM cell
Setup all exposures were performed at room temperature in 5-ml round-bottom tubes with 0.5 ml of cell suspension per tube
Sham exposure A sham exposure was conducted.
Additional info because no significant differences were observed between control and sham-exposed cells, the data from both were pooled to compare with the effects of EMF
Parameters
Measurand Value Type Method Mass Remarks
power 2 W cf. remarks measured - in pulse
SAR 5.4 mW/kg mean measured and calculated - -
Additional parameter details
At the place of exposure, static magnetic field was 58 ± 6 µT , background magnetic field < 50 nT, rms
Measurement and calculation details
the SAR-value was determined by power loss measurements and FDTD calculations; transmitted and reflected power was measured at CW exposure (915 MHz, 0.25 W), with and without sample tubes in the TEM-cell using a power meter and a coaxial directional coupler; because the absorbed power in the 0.5-ml sample was too small to be measured, the measurements were performed using 5-ml samples instead; numerical calculations were performed using the FDTD method for CW exposure (912 MHz, 2 W); the routine was run for seven cycles to assure that the results have converged; average SAR was calculated through extrapolation to the pulsed GSM signal with a duty factor of 0.125 and 2 W during the pulses The difference between the FDTD-derived value and the measured SAR should be explained by different coupling of the samples, 0.5 ml and 5 ml, to the field in the exposure system
Reference articles
Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated material:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The findings have shown that microwaves from GSM mobile phone affected chromatin conformation in human normal and transformed lymphocytes. Because of the very low SAR value in the exposed samples, the microwave effects could not be attributed to heating induced by the exposure system. The exposure level in this study was far below the ICNIRP value.
GSM microwaves under specific conditions of exposure affected human lymphocytes similar to stress response. The findings indicated that the microwave effects differ at various GSM frequencies and vary between donors.
Study character:

Study funded by

  • Swedish Council for Working Life and Social Research (FAS)
  • Swedish Radiation Protection Authority (SSI)

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