Study type: Medical/biological study (experimental study)

Microwave exposure induces Hsp70 and confers protection against hypoxia in chick embryos. med./bio.

Published in: J Cell Biochem 2002; 86 (3): 490-496

Aim of study (acc. to author)

To determine if microwave exposure could elicit a biological effect in the absence of thermal stress, chick embryos were exposed to athermal microwave radiation (915 MHz) to look for induction of Hsp70 and oxidative stress protection.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 915 MHz
Exposure duration: continuous for 30 min
  • power: 3.5 W unspecified
  • SAR: 1.75 W/kg unspecified
  • power: 5 W unspecified
  • SAR: 2.5 W/kg unspecified
Exposure 2: 30–90 Hz
Exposure duration: continuous for 30 min

Exposure 1

Main characteristics
Frequency 915 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 30 min
Exposure setup
Exposure source
Chamber The Crawford cell having two chambers was mounted vertically on a table in a water-jacketed incubator maintained at 37.8°C.
Setup Four eggs were placed vertically in each chamber with their narrow side down using holders on Plexiglas shelves. The MW signal was routed from top to bottom. Control eggs were placed in the same holders outside of the cell but in the same incubator. Matching of the Crawford cell was performed by adjusting the double stub tuner prior to each exposure period using dummy egg samples.
Additional info Temperature increase in the samples was ~1.5°C at 5 W. Positive control was performed by placing eggs in a water-tight bag in a 43°C water bath for 1 h.
Parameters
Measurand Value Type Method Mass Remarks
power 3.5 W unspecified measured - -
SAR 1.75 W/kg unspecified unspecified - -
power 5 W unspecified measured - -
SAR 2.5 W/kg unspecified unspecified - -

Exposure 2

Main characteristics
Frequency 30–90 Hz
Type
Exposure duration continuous for 30 min
Modulation
Modulation type cf. additional info
Additional info

random noise

Exposure setup
Exposure source
Additional info For some exposures, superimposed random ELF-EM noise fields (band width 30 to 90 Hz; 20 µT) were applied using Helmholtz coils placed within the incubator and including the Crawford cell within their uniform MF exposure area (see reference article for more details).
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 20 µT - - - -

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)

Microwave frequency electromagnetic fields stress embryonic cells and, without causing a significant temperature increase, enhance Hsp70 protein levels. Chick embryos pre-exposed to radiofrequency electromagnetic fields prior to hypoxic stress had significantly higher survival rates after the hypoxic insult than controls.

Study character:

Study funded by

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