Medical/biological study (experimental study)

Effects of subchronic exposure to a 1439 MHz electromagnetic field on the microcirculatory parameters in rat brain med./bio.

By: Masuda H, Ushiyama A, Hirota S, Wake K, Watanabe S, Yamanaka Y, Taki M, Ohkubo C

Published in: In Vivo 2007; 21 (4): 563-570

Aim of study (acc. to author)

To study the effects of repeated radiofrequency electromagnetic field exposure (4 weeks, subchronic) on cerebral microcirculation, including blood-brain barrier function, in rat brain.

Background/further details

30 rats were divided into three groups: exposure group, sham exposure group, and cage control group (each group consisted of 10 rats) and rats were non-anesthetized during exposure. A "closed cranial window" was implanted into the parietal region.

Endpoint

effects on the neurological system: microcirculation in brain

Exposure

- TDMA
- mobile communications
- mobile phone
- digital mobile phone
- PDC

Exposure	Parameters
Exposure 1: 1,439 MHz Modulation type: pulsed Exposure duration: repeated daily exposure, 60 min/day, 5 days/week, for 4 weeks	SAR: 2.4 W/kg average over mass (brain) SAR: 0.64 W/kg average over mass (whole body)

Exposure 1

Main characteristics

Frequency	1,439 MHz
Type	electromagnetic field
Charakteristic	near field
Exposure duration	repeated daily exposure, 60 min/day, 5 days/week, for 4 weeks
Additional info	Watanabe S, Taki M, Yamanaka Y: A microwave exposure setup for the head of Sprague-Dawley rats. Proc. XXVIth General Assembly of the International Union of Radio Science (URSI), pp 863, 1999.

Modulation

Modulation type	pulsed
Pulse width	6.67 ms
Repetition frequency	50 Hz
Additional info	TDMA signal for PDC (Japanese mobile phone standard) having a peak power 3-fold higher than the temporal average

Exposure setup

Exposure source	monopole anechoic chamber
Setup	Rats in acrylic holders were placed on a carousel with their heads towards the central antenna [Watanabe et al., 1999].
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2.4 W/kg	average over mass	-	brain	-
SAR	0.64 W/kg	average over mass	-	whole body	-

Exposed system:

animal
rat/Sprague-Dawley
partial body: head

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: microcirculation in brain (blood-brain barrier permeability (sodium fluorescein & FITC-dextran accumulation), leukocyte behavior, plasma velocity, vessel diameter; closed cranial window method; fluorescence microscopy; confocal microscopy)
body weight

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

before exposure
during exposure
after exposure

Main outcome of study (acc. to author)

The three microcirculatory parameters examined (blood brain barrier permeability, leukocyte behavior, plasma velocity) revealed no significant changes after four weeks' exposure. The data suggest that there were no effects on the cerebral microcirculation under the given radiofrequency electromagnetic field exposure conditions.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Committee to Promote Research on the Possible Biological Effects of Electromagnetic Fields, Japan
Ministry of Internal Affairs and Communications, Japan

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