Study type: Medical/biological study (experimental study)

Induction of calcium-ion efflux from brain tissue by radio frequency radiation: Effects of modulation frequency and field strength. med./bio.

Published in: Radio Sci 1979; 14: 93-98

Aim of study (acc. to author)

To investigate the effects of 147 MHz radiofrequency radiation, which was AM modulated at different frequencies between 2 and 30 Hz, on the calcium efflux from chicken brain tissue in vitro.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 147 MHz
Modulation type: AM, CW
Exposure duration: continuous for 20 min
Exposure 2: 147 MHz
Modulation type: AM, CW
Exposure duration: continuous for 20 min
  • power density: 2 mW/cm² maximum (0.5, 0.75, 1.0, 1.5 or 2.0 mW/cm²)

Exposure 1

Main characteristics
Frequency 147 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 20 min
Modulation
Modulation type AM, CW
Modulation frequency 0–30 Hz
Modulation depth 95 %
Additional info

sinusoidal: 0, 3, 9, 16, or 30 Hz

Exposure setup
Exposure source
Chamber The rectangular strip transmission line (Crawford cell), 60 cm long, 13.9 x 8.3 cm outside dimensions, center conductor 10 cm wide [Crawford, 1974; Weil, 1978] was housed in a foamed polystyrene chamber.
Setup The tissue samples in clear plastic tubes (17 mm x 40 mm) containing 1 ml of medium were placed in symmetrically arranged racks on either side of the center conductor.
Sham exposure A sham exposure was conducted.
Additional info Similar racks containing the control samples were placed on small shelves within the chamber alongside the TEM cell where the field strength was more than 30 dB lower than in the cell.
Parameters
Measurand Value Type Method Mass Remarks
power density 0.75 mW/cm² - - - -
SAR 75 µW/g - estimated - -

Exposure 2

Main characteristics
Frequency 147 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 20 min
Modulation
Modulation type AM, CW
Modulation frequency 16 Hz
Modulation depth 95 %
Additional info

sinusoidal

Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power density 2 mW/cm² maximum - - 0.5, 0.75, 1.0, 1.5 or 2.0 mW/cm²

Reference articles

  • Crawford ML (2016): Generation of standard EM fields using TEM transmission cells
  • Weil CM (1978): The Characteristic Impedance of Rectangular Transmission Lines with Thin Center Conductor and Air Dielectric

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Calcium efflux was statistically significant increased at a modulation frequency of 16 Hz and at a power density of 0.7 mW/cm2.

Study character:

Study funded by

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