Medical/biological study (experimental study)

Single- and double-strand DNA breaks in rat brain cells after acute exposure to radiofrequency electromagnetic radiation. med./bio.

By: Lai H, Singh NP

Published in: Int J Radiat Biol 1996; 69 (4): 513-521

Exposure	Parameters
Exposure 1: 2,450 MHz Modulation type: pulsed Exposure duration: continuous for 2 h	power density: 2 mW/cm² spatial average SAR: 1.2 W/kg average over mass (whole body) ([Chou et al., 1984])
Exposure 2: 2,450 MHz Modulation type: CW Exposure duration: continuous for 2 h	power density: 2 mW/cm² spatial average SAR: 1.2 W/kg average over mass (whole body) ([Chou et al., 1984])

Exposure 1

Main characteristics

Frequency	2,450 MHz
Type	electromagnetic field
Charakteristic	guided field
Polarization	circular
Exposure duration	continuous for 2 h

Modulation

Modulation type	pulsed
Pulse width	2 µs
Repetition frequency	500 Hz

Exposure setup

Exposure source	circular waveguide TE₁₁ mode
Setup	The cylindrical waveguide system [Guy et al., 1979] consisted of individual exposure tubes made of galvanised wire screen that contained a plastic chamber (with a floor of glass rods) to house a rat allowed to move freely.
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	2 mW/cm²	spatial average	unspecified	-	-
SAR	1.2 W/kg	average over mass	cf. remarks	whole body	[Chou et al., 1984]

Additional parameter details

The applied SAR was not expected to produce a significant change in body temperature [Lai et al., 1984].

Measurement and calculation details

Local SAR measured in eight brain regions varied from 0.5 to 2.0 W/kg per mW/cm² [Chou et al., 1985]. Waveguides were calibrated and checked from time to time.

Exposure 2

Main characteristics

Frequency	2,450 MHz
Type	electromagnetic field
Charakteristic	guided field
Polarization	circular
Exposure duration	continuous for 2 h

Modulation

Modulation type	CW

Exposure setup

Exposure source	same setup as exposure 1
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	2 mW/cm²	spatial average	unspecified	-	-
SAR	1.2 W/kg	average over mass	cf. remarks	whole body	[Chou et al., 1984]

Reference articles

Chou CK et al. (1985): Specific absorption rate in rats exposed to 2,450-MHz microwaves under seven exposure conditions.
Chou CK et al. (1984): SAR in rats exposed in 2,450-MHz circularly polarized waveguides.
Lai H et al. (1984): Effects of acute low-level microwaves on pentobarbital-induced hypothermia depend on exposure orientation.
Guy AW et al. (1979): Circularly polarized 2450 MHz waveguide system for chronic exposure of small animals to microwaves.

Exposed system:

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: DNA single-strand breaks and double-strand breaks (alkaline microgel electrophoresis methode)

Investigated system:

DNA/RNA
intact cell/cell culture

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

An increase in both types of DNA breaks was observed after exposure to either the pulsed or continuous-wave radiation, but no significant difference was observed between the effects of the two forms of radiation.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

National Institute of Environmental Health Sciences (NIEHS), North Carolina, USA

Deshmukh PS et al. (2015): Cognitive impairment and neurogenotoxic effects in rats exposed to low-intensity microwave radiation.
Deshmukh PS et al. (2013): Detection of Low Level Microwave Radiation Induced Deoxyribonucleic Acid Damage Vis-a-vis Genotoxicity in Brain of Fischer Rats.
Chaturvedi CM et al. (2011): 2.45 GHz (CW) microwave irradiation alters circadian organization, spatial memory, DNA structure in the brain cells and blood cell counts of male mice, Mus musculus.
Kesari KK et al. (2010): Mutagenic response of 2.45 GHz radiation exposure on rat brain.
Belyaev IY et al. (2009): Microwaves from UMTS/GSM mobile phones induce long-lasting inhibition of 53BP1/gamma-H2AX DNA repair foci in human lymphocytes.
Koyama S et al. (2007): Effects of 2.45 GHz electromagnetic fields with a wide range of SARs on bacterial and HPRT gene mutations.
Verschaeve L et al. (2006): Investigation of co-genotoxic effects of radiofrequency electromagnetic fields in vivo.
Paulraj R et al. (2006): Single strand DNA breaks in rat brain cells exposed to microwave radiation.
Lai H et al. (2005): Interaction of Microwaves and a Temporally Incoherent Magnetic Field on Single and Double DNA Strand Breaks in Rat Brain Cells.
Malyapa RS et al. (1998): DNA damage in rat brain cells after in vivo exposure to 2450 MHz electromagnetic radiation and various methods of euthanasia.
Lai H et al. (1995): Acute low-intensity microwave exposure increases DNA single-strand breaks in rat brain cells.

Single- and double-strand DNA breaks in rat brain cells after acute exposure to radiofrequency electromagnetic radiation. med./bio.

Aim of study (acc. to author)

Endpoint

Exposure

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Additional parameter details

Measurement and calculation details

Exposure 2

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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