Study type: Medical/biological study (experimental study)

Oxidative stress precedes circulatory failure induced by 35-GHz microwave heating. med./bio.

Published in: Shock 2000; 13 (1): 52-59

Aim of study (acc. to editor)

To investigate the hypothesis whether oxidative stress may play a role in the pathophysiology of microwave-induced circulatory failure. The question was examined by probing organs for 3-nitrotyrosine (3-NT), a marker of oxidative stress.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 35 GHz
Modulation type: CW
Exposure duration: until 38°C (15 ± 3 min), 39°C (24 ± 1.5 min), 40°C (33.7 ± 1.9 min) or 41°C (44.2 ± 1.8 min) or until blood pressure 75mmHg (60.3 ± 2.4 min)
  • SAR: 13 mW/g cf. remarks (whole body) (pls.see reference article.)
  • power density: 750 W/m² unspecified

Exposure 1

Main characteristics
Frequency 35 GHz
Type
Charakteristic
Polarization
Exposure duration until 38°C (15 ± 3 min), 39°C (24 ± 1.5 min), 40°C (33.7 ± 1.9 min) or 41°C (44.2 ± 1.8 min) or until blood pressure 75mmHg (60.3 ± 2.4 min)
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.1 m
Chamber RF-shielded anechoic chamber maintained at 27°C, 20% humidity.
Setup The animal was centered along the boresight and exposed in a Plexiglass holder in a H-orientation (long axis of the body parallel to magnetic field)
Additional info Animals were divided into 7 groups (n=8/group): i) animals were placed on the exposure platform but were not exposed and were heated with water-perfused heating pad until 37°C was reached ii)-v) Animals were exposed to microwave until 38, 39, 40 or 41°C were reached vi) Animals were exposed until 75 mmHg was reached vii) animals were anesthetized and instrumented but were not exposed and the temperature was maintained at 37°C and monitored for 55 min as a time contol.
Parameters
Measurand Value Type Method Mass Remarks
SAR 13 mW/g cf. remarks cf. remarks whole body pls.see reference article.
power density 750 W/m² unspecified measured - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The findings suggest that oxidative stress occurs in many organs during microwave heating. Because nitration occurs after microwave exposures that are not associated with circulatory collapse, systemic oxidative stress, as evidenced by tissue accumulation of 3-NT, is not correlated with circulatory failure in this model of shock.

Study character:

Study funded by

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