Medical/biological study (experimental study)

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 med./bio.

By: Dawe AS, Nylund R, Leszczynski D, Kuster N, Reader T, de Pomerai DI

Published in: Bioelectromagnetics 2008; 29 (2): 92-99

Aim of study (acc. to author)

To study whether higher irradiation doses and/or pulse modulation can cause measurable heat-shock protein reporter gene induction in Caenorhabditis elegans (nematodes) in the absence of heating artefacts, transgenic worms were exposed to 1.8 GHz electromagnetic fields at SAR values of 1.8 W/kg for 2.5 h at 25°C.

Background/further details

The radiofrequency fields used in previous Caenorhabditis elegans studies were much weaker (see publication 4466, publication 4467, publication 6611, and publication 12968).

Endpoint

molecular biosynthesis: expression of heat shock protein

Exposure

- mobile communications
- digital mobile phone
- GSM

Exposure	Parameters
Exposure 1: 1.8 GHz Modulation type: CW Exposure duration: continuous for 2.5 h	SAR: 1.8 W/kg mean magnetic field strength: 1.6 A/m
Exposure 2: 1.8 GHz Modulation type: pulsed Exposure duration: continuous for 2.5 h	SAR: 1.8 W/kg mean magnetic field strength: 1.6 A/m

General information

In total, seven CW runs and five Talk-pulsed runs were completed, each involving six exposed replicates compared against six sham replicates.

Exposure 1

Main characteristics

Frequency	1.8 GHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2.5 h

Modulation

Modulation type	CW

Exposure setup

Exposure source	waveguide resonant R18
Chamber	The fully automated exposure system consisted of two identical chambers for RF or sham exposure, mounted in the same incubator, and enabled well-controlled exposures of cells in monolayers or in suspension [Schuderer et al., 2004].
Setup	The Petri dishes were exposed in H-polarization. The induced E-fields had a pronounced polarization parallel to the bottom and in the direction of the waveguide axis. The induced H-fields were orthogonal to the induced E-fields, both of which were dominantly parallel to the bottom of the dish.
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	1.8 W/kg	mean	-	-	-
magnetic field strength	1.6 A/m	-	-	-	-

Additional parameter details

The ambient ELF exposure measured in several positions within the incubator was below 5 µT rms in the entire volume of the waveguide.

Measurement and calculation details

The system monitored incident electric field strengths, ventilator currents, outlet air temperatures and state of all equipment every 10 s. Previous dosimetry [Schuderer et al., 2004] had to be extended due to the larger dimensions of C. elegans compared to cells. The gradient in z-direction was about 4 W/kg/mm, which means that the bottoms of the worms were exposed to an SAR of about 2 W/kg and the tops to 1.6 W/kg. The non-uniformity within the bottom of the dish was 23%, and the relative variability between Petri dishes and experiments was estimated to be less than 5%.

Exposure 2

Main characteristics

Frequency	1.8 GHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2.5 h

Modulation

Modulation type	pulsed
Additional info	GSM Talk signal characterized by a random change between the DTX and non-DTX or GSM Basic modes. The distribution in time was exponential with a mean duration of 10.8 s for non-DTX and 5.6 s for DTX. The dominant modulation components of this signal are 2, 8, 217, 1733 Hz, and higher harmonics [Tillmann et al., 2007].

Exposure setup

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

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	1.8 W/kg	mean	-	-	-
magnetic field strength	1.6 A/m	-	-	-	-

Reference articles

Tillmann T et al. (2007): Carcinogenicity study of GSM and DCS wireless communication signals in B6C3F1 mice
Schuderer J et al. (2004): High Peak SAR Exposure Unit With Tight Exposure and Environmental Control for In Vitro Experiments at 1800 MHz

Exposed system:

invertebrate
Caenorhabditis elegans/PC72 (transgenic, with reporter gene construct encoding beta-galactosidase under control of hsp16 heat shock promotor)
whole body

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: expression of heat shock protein/reporter gene expression (beta-galactosidase activity)

Investigated system:

isolated bio./chem. substance
dead worms

Time of investigation:

after exposure

Main outcome of study (acc. to author)

For both continuous wave and pulsed radiofrequency exposures, there was no indication that radiofrequency exposure could induce reporter gene expression above sham exposure levels. Thus, at much higher induced radiofrequency field strength (compared to previous studies and close to the maximum permitted exposure from a mobile phone handset), this particular nematode heat-shock protein gene is not up-regulated.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

IT'IS Foundation (Foundation for Research on Information Technologies in Society), Zurich, Switzerland
Mobile Telecommunications and Health Research (MTHR), UK
STUK (Radiation and Nuclear Safety Authority), Helsinki, Finland

Fasseas MK et al. (2015): Response of Caenorhabditis elegans to wireless devices radiation exposure
Ding GR et al. (2009): Comparison of Hsps expression after radio-frequency field exposure in three human glioma cell lines
Dawe AS et al. (2009): Low-intensity microwave irradiation does not substantially alter gene expression in late larval and adult Caenorhabditis elegans
Yu Y et al. (2008): Effects of exposure to 1.8 GHz radiofrequency field on the expression of Hsps and phosphorylation of MAPKs in human lens epithelial cells
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
Copty AB et al. (2006): Evidence for a specific microwave radiation effect on the green fluorescent protein
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
Wang J et al. (2006): Effects of a 2450 MHz high-frequency electromagnetic field with a wide range of SARs on the induction of heat-shock proteins in A172 cells
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
Dawe AS et al. (2006): A small temperature rise may contribute towards the apparent induction by microwaves of heat-shock gene expression in the nematode Caenorhabditis Elegans
Belyaev IY (2005): Non-thermal Biological Effects of Microwaves
Laszlo A et al. (2005): The heat-shock factor is not activated in mammalian cells exposed to cellular phone frequency microwaves
Lim HB et al. (2005): Effect of 900 MHz electromagnetic fields on nonthermal induction of heat-shock proteins in human leukocytes
Shallom JM et al. (2002): Microwave exposure induces Hsp70 and confers protection against hypoxia in chick embryos
Leszczynski D et al. (2002): Non-thermal activation of the hsp27/p38MAPK stress pathway by mobile phone radiation in human endothelial cells: Molecular mechanism for cancer- and blood-brain barrier-related effects
Tian F et al. (2002): Exposure to 2.45 GHz electromagnetic fields induces hsp70 at a high SAR of more than 20 W/kg but not at 5W/kg in human glioma MO54 cells
Kwee S et al. (2001): Changes in cellular proteins due to environmental non-ionizing radiation. I. Heat-shock proteins
de Pomerai DI et al. (2000): Microwave radiation induces a heat-shock response and enhances growth in the nematode Caenorhabditis elegans
Daniells C et al. (1998): Transgenic nematodes as biomonitors of microwave-induced stress
Cleary SF et al. (1997): Stress proteins are not induced in mammalian cells exposed to radiofrequency or microwave radiation

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 med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

General information

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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