Study type: Medical/biological study (experimental study)

Effects on protein kinase C and gene expression in a human mast cell line, HMC-1, following microwave exposure med./bio.

By: Harvey C, French PW
Published in: Cell Biol Int 2000; 23 (11): 739-748
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Aim of study (acc. to author)

To determine the effect of an electromagnetic field exposure in the microwave range (864.3MHz) on protein kinase C and gene expression in human mast cells.

Background/further details

The cells were allowed to cool during the exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 864.3 MHz
Modulation type: CW
Exposure duration: repeated daily exposure, 3 x 20 min/day at 4-h intervals, for 7 days
  • SAR: 7.3 W/kg average over mass (cf. remarks) (averaged over 20 g of medium)
  • SAR: 12.1 W/kg unspecified (unspecified) (4.9, 11.4, and 12.1 W/kg at three points)

Exposure 1

Main characteristics
Frequency 864.3 MHz
Type
Charakteristic
  • guided field
Exposure duration repeated daily exposure, 3 x 20 min/day at 4-h intervals, for 7 days
Modulation
Modulation type CW
Exposure setup
Exposure source
Chamber The exposure chamber [Donnellan et al., 1997] consisted of a cubic aluminium box of 1.1 m internal side length and contained a horizontal loop antenna mounted on a horizontal Masonite shelf located at the mid point of the chamber. The reflective walls formed a resonant chamber, and thus a complex modal field pattern was generated that was taken into account in the experimental design.
Setup Cells in 20 ml of culture medium in a 75-cm² flask were placed in the exposure chamber.
Sham exposure A sham exposure was conducted.
Additional info The cells were allowed to cool during the exposure. After 20 min, there was less than 1°C difference between the temperature of the culture medium in the exposed (26.5°C) and sham (25.8°C) flasks, and this difference occurred only during the last 5 min of the exposure.
Parameters
Measurand Value Type Method Mass Remarks
SAR 7.3 W/kg average over mass determined by power loss cf. remarks averaged over 20 g of medium
SAR 12.1 W/kg unspecified measured unspecified 4.9, 11.4, and 12.1 W/kg at three points
Measurement and calculation details

The exact frequency was calculated using a frequency counter. Exposimetry characterisation of the exposure chamber was carried out by Telstra, Melbourne [Anderson et al., 1998]. SAR values were determined using two methods: power loss and thermal measurements using millimetre-sized fluoroptic temperature sensors at three locations within the flask filled with 20 g of gelled culture medium to minimise thermal diffusion due to fluid convective currents. Anderson V, Rowley J, Laurence J, 1998. Limited characterisation of an in vitro radiofrequency exposure facility at the Centre for Immunology, St Vincent's Hospital, Sydney. Telstra Research Laboratories, Melbourne, Australia, 29 April 1998.

Reference articles

  • Donnellan M et al. (1997): Effects of exposure to electromagnetic radiation at 835 MHz on growth, morphology and secretory characteristics of a mast cell analogue, RBL-2H3

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

There was no significant morphological difference between the control HMC-1 cells and the exposed cells. There was a consistent trend for an increase in the amount of immunoreactive protein kinase C in the membrane fraction of the exposed cells and a concomitant decrease in the cytosolic fraction. Reproducible and significant changes in expression were seen in only three out of a total of 588 genes screened. The results provide evidence that low-level microwave exposure can affect both gene expression and molecules involved in important cell regulatory functions.

Study character:

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