Study type: Medical/biological study (experimental study)

Microwave alteration of the blood-brain barrier system of rats. med./bio.

Published in: Brain Res 1977; 126 (2): 281-293

Aim of study (acc. to author)

To corroborate and extend the work of Frey et al. (1975) on microwave induced changes in permeability of blood-brain barrier in rats.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.3 GHz
Modulation type: CW
Exposure duration: continuous for 20 min
  • power density: 30 µW/cm² mean (0.05 mWcm², 0.1 mW/cm², 0.2 mW/cm², 0.3 mW/cm², 0.4 mW/cm², 0.6 mW/cm², 0.8 mW/cm² and 2.0 mW/cm²)
Exposure 2: 1.3 GHz
Modulation type: pulsed
Exposure duration: 20 min

Exposure 1

Main characteristics
Frequency 1.3 GHz
Type
Waveform
Polarization
Exposure duration continuous for 20 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Chamber anechoic chamber (5 m x 5 m x10m) maintained at 22°C, wedge and pyramidally shaped absorber (- 40dB), styrofoam pedestal
Additional info Rats were exposed in one of two different exposure procedures; the rats were irradiated without being anesthetized and were placed in a pie shaped, well ventilated styrofoam enclosure. The box was placed on a styrofoam platform with the rat facing the center of the emitting horn and aligned with the longitudinal axis of the horn. The rats could not turn around. In other tests rats were anesthetized and placed directly on the styrofoam platform facing the mouth of the horn.
Parameters
Measurand Value Type Method Mass Remarks
power density 30 µW/cm² mean measured - 0.05 mWcm², 0.1 mW/cm², 0.2 mW/cm², 0.3 mW/cm², 0.4 mW/cm², 0.6 mW/cm², 0.8 mW/cm² and 2.0 mW/cm²

Exposure 2

Main characteristics
Frequency 1.3 GHz
Type
Waveform
Exposure duration 20 min
Modulation
Modulation type pulsed
Additional info

signals with 5, 50, 250, and 1000 pps and 0.5 µs, 2.0 µs, 10 µs and 20 µs were used.

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power density 1 W/m² mean measured - at 1000 pps and 0.5 µs pulse width
power density 2 W/m² mean measured - at 1000 pps and 0.5 µs pulse width
power density 3 W/m² mean measured - at 1000 pps and 0.5 µs pulse width
power density 4 W/m² mean measured - at 1000 pps and 0.5 µs pulse width
power density 6 W/m² mean measured - at 1000 pps and 0.5 µs pulse width
power density 20 W/m² mean measured - at 1000 pps and 10 µs pulse width
power density 30 µW/cm² mean measured - at 5 pps and 10 µs pulse width
power density 50 nW/cm² mean measured - at 5 pps and 10 µs pulse width
power density 3 W/m² mean measured - at 50 pps and 10 µs pulse width
power density 3 W/m² mean measured - at 250 pps and 20 µs pulse width
power density 3 W/m² mean measured - at 250 pps and 2 µs pulse width
power density 8 W/m² mean measured - at 1000 pps and 0.5 µs pulse width

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data confirmed the results of the study of Frey et al. (1975): microwaves cause a temporary increase in permeability of blood-brain barrier. This effect was dependent on the field characteristics.

Study character:

Study funded by

Replicated studies

Replication studies

Related articles