Study type: Medical/biological study (experimental study)

Millimeter waves enhance delayed-type hypersensitivity in mouse skin. med./bio.

Published in: Electro Magnetobiol 1999; 18 (2): 165-176

Aim of study (acc. to author)

To study the effect of electromagnetic millimeter waves on delayed-type hypersensitivity and irritant contact sensitivity in mice.

Background/further details

Female mice (7 weeks old) were assigned to exposure groups (n=80) and three control groups (sham exposure: n=47; unsensitized controls: n=3, no sensitization, but challenge; solvent control: n=5). Different frequencies and power densities were examined. In the experiments of the delayed-type hypersensitivity (field 1 and 2) the animals were sensitized by topical application of highly concentrated dinitrochlorobenzene (DNCB) on the right ear. Later they were challenged with DNCB in lower concentration. To study the irritant contact sensitivity (field 3) tetradecanoylphorbol acetate was applied and the allergic reaction was estimated in terms of increased ear thickness.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 53.6 GHz
Modulation type: CW
Exposure duration: repeated daily exposure, 30 min/day, for 3 days
Exposure 2: 42.2 GHz
Modulation type: CW
Exposure duration: repeated daily exposure, 30 min/day, for 3 days
Exposure 3: 42.2 GHz
Modulation type: CW
Exposure duration: repeated daily exposure, 30 min/day, for 3 days

General information

for experiment 1 (Expo 1) animals were treated in four groups: 1.) sensitized with a topical application of 10 µl of 2.5% DNCB solution to the right ear + challenged with 10 µl of 0.6 % DNCB at the right ear + irradiated 2.) sensitized with a topical application of 10 µl of 2.5% DNCB solution to the right ear + challenged with 10 µl of 0.6 % DNCB at the right ear + sham irradiated 3.) not sensitized but challenged with 10 µl of 0.6 % DNCB at the right ear and not irradiated 4.) control group - neither sensitized nor challenged nor irradiated for experiment 2 (Expo 2) animals were treated in three groups: 1.) irradiated with 43.1 mW 2.) irradiated with 13.5 mW iii) sham irradiated

Exposure 1

Main characteristics
Frequency 53.6 GHz
Type
Exposure duration repeated daily exposure, 30 min/day, for 3 days
Additional info ± 0.2 GHz
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 5 mm
Setup mice placed on a non-metallic hot-water thermostatic blanket set at 38°C; horn aperture positioned above the mid-back of the mice
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 15.3 mW mean measured - ± 0.8 mW
power density 14.8 mW/cm² maximum calculated - ± 2.4 mW/cm²
SAR 296 W/kg maximum measured - ± 47 W/kg

Exposure 2

Main characteristics
Frequency 42.2 GHz
Type
Exposure duration repeated daily exposure, 30 min/day, for 3 days
Additional info ± 0.2 GHz
Modulation
Modulation type CW
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 13.5 mW mean measured - ± 0.5 mW
power density 12.7 mW/cm² maximum calculated - ± 2.8 mW/cm²
SAR 254 W/kg maximum measured - ± 55 W/kg
power 43.1 mW mean measured - ± 3.1 mW
power density 42.4 mW/cm² maximum calculated - ± 7.7 mW/cm²
SAR 849 W/kg maximum measured - ± 153 W/kg

Exposure 3

Main characteristics
Frequency 42.2 GHz
Type
Exposure duration repeated daily exposure, 30 min/day, for 3 days
Additional info ± 0.2 GHz
Modulation
Modulation type CW
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 35 mW mean measured - ± 1.1 mW
power density 34.6 mW/cm² maximum calculated - ± 5.6 mW/cm²
SAR 691 W/kg maximum measured - ± 112 W/kg

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The 53.6 GHz exposed animals showed a significant enhancement of the delayed-type hypersensitivity reaction compared with the sham exposure animals. The unsensitized group showed only a low-grade delayed-type hypersensitivity response. The solvent control group did not show any delayed-type hypersensitivity response.
In the 42.2 GHz, 13.5 mW exposed animals no significant difference in ear thickness was observed compared to the sham exposure group. In the 43.1 mW group a significant enhancement of the delayed-type hypersensitivity reaction compared with the sham exposure animals was observed.
The investigation of the irritant contact sensitivity did not reveal any difference in ear thickness between the irradiated animals compared to the sham exposure group.

Study character:

Study funded by

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