Medical/biological study (experimental study)

Effect of 900 MHz electromagnetic fields on nonthermal induction of heat-shock proteins in human leukocytes med./bio.

By: Lim HB, Cook GG, Barker AT, Coulton LA

Published in: Radiat Res 2005; 163 (1): 45-52

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Aim of study (acc. to author)

To study whether exposure to mobile phone-type irradiation causes a nonthermal stress response in human leukocytes.

Background/further details

Positive (heat-stressed at 42°C) and negative (kept at 37°C) control samples were incubated simultaneously.

Endpoint

molecular biosynthesis: activation of stress response genes

Exposure

- mobile communications
- GSM

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: CW Exposure duration: continuous for 4 hours This study was performed to investigate the effects of different power levels.	SAR: 0.4 W/kg mean (unspecified) (input power level of 3 W) SAR: 2 W/kg mean (unspecified) (input power level of 14 W) SAR: 3.6 W/kg mean (unspecified) (input power level of 25 W)
Exposure 2: 900 MHz Modulation type: CW Exposure duration: continuous for 20 min, 1 h or 4 h This study was performed to investigate the effects of different exposure durations.	SAR: 2 W/kg mean (unspecified)
Exposure 3: 900 MHz Modulation type: pulsed Exposure duration: continuous for 20 min, 1 h or 4 h This study was performed to investigate the effects of different exposure durations using a GSM signal.	SAR: 0.4 W/kg mean (unspecified)

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	continuous for 4 hours
Additional info	This study was performed to investigate the effects of different power levels.

Modulation

Modulation type	CW

Exposure setup

Exposure source	TEM cell
Setup	The human peripheral blood was exposed or sham-exposed in Petri dishes in a calibrated TEM cell placed in an incubator. The cell was operated in travelling wave mode, being terminated by a matched load, which increased the uniformity of the exposure.
Additional info	Positive (heat-stressed at 42°C) and negative (kept at 37°C) control groups were incubated simultaneously in the same incubator. The sham-exposed dish and the positive control were heated by heater mats, the negative control was in equilibrium with the incubator temperature. The peak static magnetic flux density generated by the heater mat and measured 2 mm above the mat using an incremental gaussmeter was below 15 µT.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.4 W/kg	mean	measured and calculated	unspecified	input power level of 3 W
SAR	2 W/kg	mean	measured and calculated	unspecified	input power level of 14 W
SAR	3.6 W/kg	mean	measured and calculated	unspecified	input power level of 25 W

Additional parameter details

The standard deviation of the FDTD-predicted SAR was about 43% of the mean.

Measurement and calculation details

The mean SAR experienced by the exposed blood cells was predicted using a specifically developed FDTD modelling software. A detailed description of this dosimetry can be found in the reference article. The FDTD-predicted results were in good agreement with those published for a slightly different geometry and with SAR values calculated from thermal measurements. The reading of an ammeter measuring the input current of the power amplifier was used as a surrogate for the input power applied to the TEM cell.

Exposure 2

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	continuous for 20 min, 1 h or 4 h
Additional info	This study was performed to investigate the effects of different exposure durations.

Modulation

Modulation type	CW

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2 W/kg	mean	calculated	unspecified	-

Exposure 3

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	continuous for 20 min, 1 h or 4 h
Additional info	This study was performed to investigate the effects of different exposure durations using a GSM signal.

Modulation

Modulation type	pulsed
Duty cycle	12.5 %

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.4 W/kg	mean	calculated	unspecified	-

Reference articles

Lim HB et al. (2002): FDTD design of RF dosimetry apparatus to quantify the effects of near fields from mobile handsets on stress response mechanisms of human whole blood

Exposed system:

blood samples

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: activation of stress response genes (content of HSP70 and HSP27 in the cells; flow cytometry)

Investigated system:

intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Heat caused an increase in the number of cells expressing stress proteins (HSP70, HSP27) and this increase was dependent on time. However, no statistically significant difference was detected in the number of cells expressing stress proteins after exposure. These data suggest that mobile phone-type irradiation is not a stressor of normal human lymphocytes and monocytes, in contrast to mild heating.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Medical Research Council, UK

Kim HN et al. (2012): Analysis of the cellular stress response in MCF10A cells exposed to combined radio frequency radiation
Dawe AS et al. (2008): Continuous wave and simulated GSM exposure at 1.8 W/kg and 1.8 GHz do not induce hsp16-1 heat-shock gene expression in Caenorhabditis elegans
Paparini A et al. (2008): No evidence of major transcriptional changes in the brain of mice exposed to 1800 MHz GSM signal
Valbonesi P et al. (2008): Evaluation of HSP70 expression and DNA damage in cells of a human trophoblast cell line exposed to 1.8 GHz amplitude-modulated radiofrequency fields
Chauhan V et al. (2007): Analysis of gene expression in two human-derived cell lines exposed in vitro to a 1.9 GHz pulse-modulated radiofrequency field
Lantow M et al. (2006): ROS release and Hsp70 expression after exposure to 1,800 MHz radiofrequency electromagnetic fields in primary human monocytes and lymphocytes
Chauhan V et al. (2006): Gene Expression Analysis of a Human Lymphoblastoma Cell Line Exposed In Vitro to an Intermittent 1.9 GHz Pulse-Modulated Radiofrequency Field
Qutob SS et al. (2006): Microarray gene expression profiling of a human glioblastoma cell line exposed in vitro to a 1.9 GHz pulse-modulated radiofrequency field
Chauhan V et al. (2006): Analysis of proto-oncogene and heat-shock protein gene expression in human derived cell-lines exposed in vitro to an intermittent 1.9 GHz pulse-modulated radiofrequency field
Lee JS et al. (2006): Radiofrequency radiation does not induce stress response in human T-lymphocytes and rat primary astrocytes
Gurisik E et al. (2006): An in vitro study of the effects of exposure to a GSM signal in two human cell lines: monocytic U937 and neuroblastoma SK-N-SH
Vanderwaal RP et al. (2006): HSP27 phosphorylation increases after 45°C or 41°C heat shocks but not after non-thermal TDMA or GSM exposures

Effect of 900 MHz electromagnetic fields on nonthermal induction of heat-shock proteins in human leukocytes med./bio.

Aim of study (acc. to author)

Background/further details

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

Exposure 3

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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