Study type: Medical/biological study (experimental study)

The heat-shock factor is not activated in mammalian cells exposed to cellular phone frequency microwaves. med./bio.

Published in: Radiat Res 2005; 164 (2): 163-172

Aim of study (acc. to author)

To determine whether acute and chronic exposures to FDMA- or CDMA -modulated microwaves have effects on the stress response of human and rodent cells. The activation of the DNA-binding activity of heat-shock factor (HSF) which leads to the transcription of heat shock proteins was measured.

Background/further details

The experiments were conducted in an exposure system with reliable and precise temperature control. The gel shift assay was calibrated to detect an increase of about 10 % in the activation of the DNA-binding activity of heat-shock factor after an increase of 1° C in temperature.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 835.62 MHz
Exposure duration: continuous for 5, 15, 30 and 60 min or 24 h
Exposure 2: 847.74 MHz
Exposure duration: continuous for 5, 15, 30 and 60 min or 24 h

Exposure 1

Main characteristics
Frequency 835.62 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 5, 15, 30 and 60 min or 24 h
Additional info FDMA
Modulation
Modulation type cf. additional info
Additional info

FDMA

Exposure setup
Exposure source
Chamber The irradiator facility was set up in a temperature-controlled room. It consisted of 10 radial transmission line (RTL) irradiators formed by two parallel metal plates 4.3 cm apart with the bottom aluminium plate providing mechanical support and temperature equalization among flasks. Each RTL irradiator had a central conical antenna that emitted TEM waves radially outward through the cavity that was bounded by an annulus of RF-absorbing foam backed by a perforated aluminium lamina. The design and calibration of these irradiators used in several studies have been described in detail in the reference articles.
Setup Up to 16 T-75 sealed culture flasks each containing 40 ml of medium (to minimize edge effects) were positioned in each of the RTLs around the antenna. The high SAR values were obtained by loading each flask dielectrically with a shim of alumina (Al2O3) ceramic as described previously.
Additional info The temperature of the culture medium in the flasks was maintained at 37 ± 0.3°C with the aid of thermocouples on the bottom plate of the RTL that were calibrated periodically using intraflask fibre-optic probes. All exposures were performed after the warm-up cycle of the RTL was complete.
Parameters
Measurand Value Type Method Mass Remarks
SAR 0.6 W/kg mean measured and calculated - ± 0.3 W/kg
SAR 5 W/kg mean measured and calculated - 4.4-5 W/kg

Exposure 2

Main characteristics
Frequency 847.74 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 5, 15, 30 and 60 min or 24 h
Additional info CDMA
Modulation
Modulation type cf. additional info
Additional info

CDMA

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 0.6 W/kg mean measured and calculated - ± 0.3 W/kg
SAR 5 W/kg mean measured and calculated - 4.4-5 W/kg

Reference articles

  • Pickard WF et al. (2000): Experimental and numerical determination of SAR distributions within culture flasks in a dielectric loaded radial transmission line.
  • Moros EG et al. (1999): The radial transmission line as a broad-band shielded exposure system for microwave irradiation of large numbers of culture flasks.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The acute and chronic exposure of human and rodents cells in culture to FDMA- and CDMA-modulated microwaves did not result in the activation of the DNA-binding activity of heat-shock factor which is a necessary condition for induction of stress response and the synthesis of heat shock proteins.

Study character:

Study funded by

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