Study type: Medical/biological study (experimental study)

Increased resorptions in CBA mice exposed to low-frequency magnetic fields: an attempt to replicate earlier observations. med./bio.

Published in: Bioelectromagnetics 1997; 18 (6): 410-417

Aim of study (acc. to author)

The aims of this study were to examine the possible effects of 50 Hz sinusoidal magnetic fields on increased resorption or fetal loss in mice, and to try to replicate former results by Frölen (publication 2782) using 20 kHz sawtooth magnetic fields.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 20 kHz
Modulation type: pulsed
Exposure duration: continuous for 8 days, 24 hrs/day
Exposure 2: 50 Hz
Exposure duration: continuous for 8 days, 24 hrs/day
Exposure 3: 50 Hz
Exposure duration: continuous for 8 days, 24 hrs/day

General information

Fairly well-described setup intended to replicate that of earlier studies. In experiment 6, only 13,5 µT were used on about half of the animals.

Exposure 1

Main characteristics
Frequency 20 kHz
Type
Waveform
  • sawtooth-shaped
Exposure duration continuous for 8 days, 24 hrs/day
Modulation
Modulation type pulsed
Rise time 45 s
Fall time 5 s
Exposure setup
Exposure source
  • four rectangular coils in a wooden rack
Setup 4 Cages, 6 animals per cage were placed on the wooden rack. Control animals were placed at least 3.5 m away from the active exposure systems but were placed in the same set-up except that the magnetic field was less than 0.1 µT.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 15 µT peak value measured - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 8 days, 24 hrs/day
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 13 µT effective value measured - corresponding magnetic field strength was 10 A/m.

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 8 days, 24 hrs/day
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 130 µT effective value measured - corresponding magnetic field strength was 100 A/m.

Reference articles

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 resorption rate in CBA/Ca mice were not affected by exposure to different magnetic fields (i.e. 50 Hz/13 µT, 50 Hz/130 µT, or 20 kHz). The resorption rate in CBA/s mice exposed to 20 kHz magnetic fields was increased compared with the study of Frölen. Therefore, the animal strain is shown to be a crucial variable in bioelectromagnetic research.

Study character:

Study funded by

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