Study type: Medical/biological study (experimental study)

Increased serum enzyme activity in microwave-exposed rats med./bio.

By: Lu ST, Michaelson SM, Pettit S
Published in: Radiat Res 1983; 96 (1): 152-159
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Aim of study (acc. to author)

Serum enzymes were studied in exposed rats as indicators for microwave-induced injury to internal organs.

Background/further details

Three different time exposure patterns were studied: a single 4 h exposure, three 4 h exposures with 3 h interval, and ten 4 h exposures with 3 h interval. In addition, the effect of a colonic temperature at 41.5°C for 30 min caused by microwave exposure was investigated.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.45 GHz
Modulation type: AM
Exposure duration: continuous for 4 hr
Exposure 2: 2.45 GHz
Modulation type: AM
Exposure duration: continuous for 3 times 4 hr
Exposure 3: 2.45 GHz
Modulation type: AM
Exposure duration: continuous for 10 times 4 hr
Exposure 4: 2.45 GHz
Modulation type: AM
Exposure duration: until colonic temperature had risen to 41.5°C + 30 min

Exposure 1

Main characteristics
Frequency 2.45 GHz
Type
Charakteristic
Exposure duration continuous for 4 hr
Modulation
Modulation type AM
Modulation frequency 120 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.6 m
Setup horn antenna mounted overhead of the 20 cm x 20 cm x 30 cm styrofoam cages
Parameters
Measurand Value Type Method Mass Remarks
SAR 11.8 W/kg - measured whole body rats exposed individually
SAR 12.22 W/kg - measured whole body 4 rats exposed simultaneously
power density 0.1 mW/cm² - - - -
power density 1 mW/cm² - - - -
power density 10 mW/cm² - - - -
power density 25 mW/cm² - - - -
power density 40 mW/cm² - - - -

Exposure 2

Main characteristics
Frequency 2.45 GHz
Type
Charakteristic
Exposure duration continuous for 3 times 4 hr
Modulation
Modulation type AM
Modulation frequency 120 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.6 m
Parameters
Measurand Value Type Method Mass Remarks
SAR 11.8 W/kg - measured whole body rats exposed individually
SAR 12.22 W/kg - measured whole body 4 rats exposed simultaneously
power density 1 mW/cm² - - - -
power density 10 mW/cm² - - - -
power density 20 mW/cm² - - - -
power density 30 mW/cm² - - - -
power density 40 mW/cm² - - - -
power density 55 mW/cm² - - - -

Exposure 3

Main characteristics
Frequency 2.45 GHz
Type
Charakteristic
Exposure duration continuous for 10 times 4 hr
Modulation
Modulation type AM
Modulation frequency 120 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.6 m
Parameters
Measurand Value Type Method Mass Remarks
SAR 11.8 W/kg - measured whole body rats exposed individually
SAR 12.22 W/kg - measured whole body 4 rats exposed simultaneously
power density 1 mW/cm² - - - -
power density 10 mW/cm² - - - -
power density 20 mW/cm² - - - -
power density 30 mW/cm² - - - -
power density 40 mW/cm² - - - -

Exposure 4

Main characteristics
Frequency 2.45 GHz
Type
Charakteristic
Exposure duration until colonic temperature had risen to 41.5°C + 30 min
Modulation
Modulation type AM
Modulation frequency 120 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.6 m
Parameters
Measurand Value Type Method Mass Remarks
SAR 11.8 W/kg - measured whole body rats exposed individually
SAR 12.22 W/kg - measured whole body 4 rats exposed simultaneously
power density 40 mW/cm² - - - during the 30 min temperture maintenance
power density 60 mW/cm² - - - during the 30 min temperture maintenance
power density 100 mW/cm² - - - during the rise of the colonic temperture

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The different microwave exposures did not induce changes in serum enzyme activity. These negative results prevented the authors from drawing any conclusion concerning the responsivness of serum enzymes to microwave exposures. On the other hand, a tentative threshold colonic temperature of 41.5°C for cellular injury could be demonstrated. The increased serum activity of glutamic-pyruvic transaminase and glutamic oxaloacetic transaminase can be a sign of a liver injury.

Study character:

Study funded by