Study type: Medical/biological study (experimental study)

Continuous wave and simulated GSM exposure at 1.8 W/kg and 1.8 GHz do not induce hsp16-1 heat-shock gene expression in Caenorhabditis elegans. med./bio.

Published in: Bioelectromagnetics 2008; 29 (2): 92-99

Aim of study (acc. to author)

To study whether higher irradiation doses and/or pulse modulation can cause measurable heat-shock protein reporter gene induction in Caenorhabditis elegans (nematodes) in the absence of heating artefacts, transgenic worms were exposed to 1.8 GHz electromagnetic fields at SAR values of 1.8 W/kg for 2.5 h at 25°C.

Background/further details

The radiofrequency fields used in previous Caenorhabditis elegans studies were much weaker (see publication 4466, publication 4467, publication 6611, and publication 12968).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.8 GHz
Modulation type: CW
Exposure duration: continuous for 2.5 h
Exposure 2: 1.8 GHz
Modulation type: pulsed
Exposure duration: continuous for 2.5 h

General information

In total, seven CW runs and five Talk-pulsed runs were completed, each involving six exposed replicates compared against six sham replicates.

Exposure 1

Main characteristics
Frequency 1.8 GHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 2.5 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Chamber The fully automated exposure system consisted of two identical chambers for RF or sham exposure, mounted in the same incubator, and enabled well-controlled exposures of cells in monolayers or in suspension [Schuderer et al., 2004].
Setup The Petri dishes were exposed in H-polarization. The induced E-fields had a pronounced polarization parallel to the bottom and in the direction of the waveguide axis. The induced H-fields were orthogonal to the induced E-fields, both of which were dominantly parallel to the bottom of the dish.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1.8 W/kg mean - - -
magnetic field strength 1.6 A/m - - - -

Exposure 2

Main characteristics
Frequency 1.8 GHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 2.5 h
Modulation
Modulation type pulsed
Additional info

GSM Talk signal characterized by a random change between the DTX and non-DTX or GSM Basic modes. The distribution in time was exponential with a mean duration of 10.8 s for non-DTX and 5.6 s for DTX. The dominant modulation components of this signal are 2, 8, 217, 1733 Hz, and higher harmonics [Tillmann et al., 2007].

Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1.8 W/kg mean - - -
magnetic field strength 1.6 A/m - - - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

For both continuous wave and pulsed radiofrequency exposures, there was no indication that radiofrequency exposure could induce reporter gene expression above sham exposure levels. Thus, at much higher induced radiofrequency field strength (compared to previous studies and close to the maximum permitted exposure from a mobile phone handset), this particular nematode heat-shock protein gene is not up-regulated.

Study character:

Study funded by

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