Medical/biological study (experimental study)

Permeability of the blood-brain barrier induced by 915 MHz electromagnetic radiation, continuous wave and modulated at 8, 16, 50, and 200 Hz med./bio.

By: Salford LG, Brun A, Sturesson K, Eberhardt JL, Persson BR

Published in: Microsc Res Tech 1994; 27 (6): 535-542

Aim of study (acc. to author)

To study the permeability of blood-brain barrier to endogenous albumin and fibrinogen during exposure to microwaves of 915 MHz as continuous wave and pulse-modulated at the various repetition rates.

Endpoint

effects on the neurological system: permeability of the blood-brain barrier

Exposure

- microwaves
- mobile communications
- GSM

Exposure	Parameters
Exposure 1: 915 MHz Modulation type: CW Exposure duration: continuous for 2 h	power: 3 W (0.2-3 W) SAR: 0.3 W/kg SAR: 1.7 W/kg SAR: 3.3 W/kg SAR: 5 W/kg
Exposure 2: 915 MHz Modulation type: pulsed Exposure duration: continuous for 2 h	power: 20 W peak value (2-20 W) SAR: 0.016 W/kg SAR: 0.04 W/kg SAR: 0.08 W/kg SAR: 0.16 W/kg
Exposure 3: 915 MHz Modulation type: pulsed Exposure duration: continuous for 2 h	power: 20 W peak value (2-20 W) SAR: 0.03 W/kg SAR: 0.08 W/kg SAR: 0.15 W/kg SAR: 0.3 W/kg SAR: 2.1 W/kg (at 4 ms pulse width and 20 W in pulse)
Exposure 4: 915 MHz Modulation type: pulsed Exposure duration: continuous for 2 h	power: 20 W peak value (1-20 W) SAR: 0.3 W/kg SAR: 0.7 W/kg SAR: 1.7 W/kg SAR: 3.3 W/kg SAR: 5 W/kg (at 6 ms pulse width and 10 W in pulse) SAR: 1 W/kg (at 0.57 ms pulse width and 20 W in pulse)
Exposure 5: 915 MHz Modulation type: pulsed Exposure duration: continuous for 2 h	power: 10 W peak value (2-10 W) SAR: 0.4 W/kg SAR: 1 W/kg SAR: 2.1 W/kg SAR: 2.9 W/kg (at 4 ms pulse width and 2 W in pulse)

Exposure 1

Main characteristics

Frequency	915 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2 h

Modulation

Modulation type	CW

Exposure setup

Exposure source	TEM cell [Crawford, 1974]
Chamber	The TEM cell was enclosed in a well ventilated wooden box supporting the outer conductor made of brass-net and the central plate, or septum, constructed of aluminium and held up by Teflon braces.
Setup	Unanaesthetized rats were placed in the upper and lower compartments of the TEM cell.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	3 W	-	-	-	0.2-3 W
SAR	0.3 W/kg	-	estimated	brain	-
SAR	1.7 W/kg	-	estimated	brain	-
SAR	3.3 W/kg	-	estimated	brain	-
SAR	5 W/kg	-	estimated	brain	-

Measurement and calculation details

The SAR values calculated from σE²/ρ are based on a crude estimate using the E-field in the TEM cell as the internal field in the rat brain.

Exposure 2

Main characteristics

Frequency	915 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2 h

Modulation

Modulation type	pulsed
Pulse width	0.57 ms
Repetition frequency	8 Hz
Pulse type	rectangular

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	20 W	peak value	-	-	2-20 W
SAR	0.016 W/kg	-	estimated	brain	-
SAR	0.04 W/kg	-	estimated	brain	-
SAR	0.08 W/kg	-	estimated	brain	-
SAR	0.16 W/kg	-	estimated	brain	-

Exposure 3

Main characteristics

Frequency	915 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2 h

Modulation

Modulation type	pulsed
Pulse width	0.57 ms
Repetition frequency	16 Hz
Pulse type	rectangular

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	20 W	peak value	-	-	2-20 W
SAR	0.03 W/kg	-	estimated	brain	-
SAR	0.08 W/kg	-	estimated	brain	-
SAR	0.15 W/kg	-	estimated	brain	-
SAR	0.3 W/kg	-	estimated	brain	-
SAR	2.1 W/kg	-	estimated	brain	at 4 ms pulse width and 20 W in pulse

Exposure 4

Main characteristics

Frequency	915 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2 h

Modulation

Modulation type	pulsed
Pulse width	4 ms
Repetition frequency	50 Hz
Pulse type	rectangular

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	20 W	peak value	-	-	1-20 W
SAR	0.3 W/kg	-	estimated	brain	-
SAR	0.7 W/kg	-	estimated	brain	-
SAR	1.7 W/kg	-	estimated	brain	-
SAR	3.3 W/kg	-	estimated	brain	-
SAR	5 W/kg	-	estimated	brain	at 6 ms pulse width and 10 W in pulse
SAR	1 W/kg	-	estimated	brain	at 0.57 ms pulse width and 20 W in pulse

Exposure 5

Main characteristics

Frequency	915 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2 h

Modulation

Modulation type	pulsed
Pulse width	0.57 ms
Repetition frequency	200 Hz
Pulse type	rectangular

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	10 W	peak value	-	-	2-10 W
SAR	0.4 W/kg	-	estimated	brain	-
SAR	1 W/kg	-	estimated	brain	-
SAR	2.1 W/kg	-	estimated	brain	-
SAR	2.9 W/kg	-	estimated	brain	at 4 ms pulse width and 2 W in pulse

Reference articles

Crawford ML (2016): Generation of standard EM fields using TEM transmission cells

Exposed system:

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: permeability of the blood-brain barrier to albumin and fibrinogen

Investigated system:

tissue slices

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Exposed animals are at risk concerning opening of the blood-brain barrier and the response is independent of pulse repetition rate. The response is the same for continuous wave as compared with pulse modulation. The response is independent of SAR in the interval 0.016 < SAR < 2.5 W/kg, but rises for SAR > 2.5 W/kg.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Ake Wibergs Foundation, Sweden
Gunnar, Arvid and Elisabeth Nilssons Research Foundation, Sweden
University of Lund, Sweden

Tang J et al. (2015): Exposure to 900 MHz electromagnetic fields activates the mkp-1/ERK pathway and causes blood-brain barrier damage and cognitive impairment in rats
Sirav B et al. (2011): Effects of radiofrequency radiation exposure on blood-brain barrier permeability in male and female rats
Nittby H et al. (2011): Nonthermal GSM RF and ELF EMF effects upon rat BBB permeability
Nittby H et al. (2009): Increased blood-brain barrier permeability in mammalian brain 7 days after exposure to the radiation from a GSM-900 mobile phone
McQuade JM et al. (2009): Radiofrequency-radiation exposure does not induce detectable leakage of albumin across the blood-brain barrier
Sirav B et al. (2009): Blood-brain barrier disruption by continuous-wave radio frequency radiation
Masuda H et al. (2009): Effects of 915 MHz electromagnetic-field radiation in TEM cell on the blood-brain barrier and neurons in the rat brain
de Gannes FP et al. (2009): Effects of head-only exposure of rats to GSM-900 on blood-brain barrier permeability and neuronal degeneration
Grafstrom G et al. (2008): Histopathological examinations of rat brains after long-term exposure to GSM-900 mobile phone radiation
Eberhardt JL et al. (2008): Blood-brain barrier permeability and nerve cell damage in rat brain 14 and 28 days after exposure to microwaves from GSM mobile phones
Masuda H et al. (2007): Effects of subchronic exposure to a 1439 MHz electromagnetic field on the microcirculatory parameters in rat brain
Masuda H et al. (2007): Effects of acute exposure to a 1439 MHz electromagnetic field on the microcirculatory parameters in rat brain
Kumlin T et al. (2007): Mobile phone radiation and the developing brain: behavioral and morphological effects in juvenile rats
Salford LG et al. (1993): Permeability of the blood-brain barrier induced by 915 MHz electromagnetic radiation, continuous wave and modulated at 8, 16, 50 and 200 Hz

Permeability of the blood-brain barrier induced by 915 MHz electromagnetic radiation, continuous wave and modulated at 8, 16, 50, and 200 Hz med./bio.

Aim of study (acc. to author)

Endpoint

Exposure

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Measurement and calculation details

Exposure 2

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 3

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 4

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 5

Main characteristics

Modulation

Exposure setup

Parameters

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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