Medical/biological study (experimental study)

Role of modulation on the effect of microwaves on ornithine decarboxylase activity in L929 cells med./bio.

By: Penafiel LM, Litovitz T, Krause D, Desta A, Mullins JM

Published in: Bioelectromagnetics 1997; 18 (2): 132-141

Aim of study (acc. to author)

To investigate the effects of microwave exposure on the enzyme activity of ornithine decarboxylase in dependence on different kinds of modulation.

Endpoint

cell function: enzyme activity

Exposure

- microwaves
- TDMA
- mobile communications
- analog mobile phone
- digital mobile phone
- D-AMPS

Exposure	Parameters
Exposure 1: 835 MHz Modulation type: CW Exposure duration: continuous for 2, 4, 6, 8, 12, 16, and 24 h	power: 0.96 W electric field strength: 0.6 V/cm mean SAR: 2.5 W/kg mean
Exposure 2: 835 MHz Modulation type: AM Exposure duration: continuous for 2, 4, 6, 8, 12, 16, and 24 h	power: 0.96 W electric field strength: 0.6 V/cm mean SAR: 2.5 W/kg mean
Exposure 3: 835 MHz Modulation type: AM Exposure duration: continuous for 8 h	power: 0.96 W electric field strength: 0.6 V/cm mean SAR: 2.5 W/kg mean
Exposure 4: 835 MHz Modulation type: AM Exposure duration: continuous for 8 h	power: 0.96 W electric field strength: 0.6 V/cm mean SAR: 2.5 W/kg mean
Exposure 5: 835 MHz Modulation type: FM Exposure duration: continuous for 2, 4, 6, 8, 12, and 16 h	power: 0.96 W electric field strength: 0.6 V/cm mean SAR: 2.5 W/kg mean
Exposure 6: 835 MHz Modulation type: pulsed Exposure duration: continuous for 8 h	power: 0.96 W electric field strength: 0.6 V/cm mean SAR: 2.5 W/kg mean
Exposure 7: 840 MHz Modulation type: FM Exposure duration: continuous for 4, 6, 8, and 10 h	power: 0.96 W electric field strength: 0.6 V/cm mean SAR: 2.5 W/kg mean
Exposure 8: 840 MHz Modulation type: pulsed Exposure duration: continuous for 4, 6, 8, 10, and 16 h	power: 0.96 W electric field strength: 0.6 V/cm mean SAR: 2.5 W/kg mean

Exposure 1

Main characteristics

Frequency	835 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2, 4, 6, 8, 12, 16, and 24 h

Modulation

Modulation type	CW

Exposure setup

Exposure source	TEM cell RF generator
Chamber	The Crawford cell with two sample chambers, located on either side of the center conductor, was mounted vertically on a rotary table and housed in a 37 °C, water-jacketed incubator. A double stub tuner was used to match the impedance of the loaded Crawford cell.
Setup	Four 25 cm² sample flasks, each containing 5 ml of culture medium, were placed as pairs, end to end, on either side of the center conductor, flat on non-conducting shelves located at approx. 7 cm from the junction between the center rectangular section and the lower tapered end.
Additional info	Four control flasks were placed at the same height on an incubator shelf cut to form a platform around the Crawford cell.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	0.96 W	-	-	-	-
electric field strength	0.6 V/cm	mean	calculated	-	-
SAR	2.5 W/kg	mean	measured	-	-

Measurement and calculation details

The SAR distribution for this exposure arrangement has been previously reported in the reference article. Measurements were taken on a grid of 48 points within each of two flasks only on one side of the conductor because the configuration ensured overall symmetry of the electric field distribution. The average electric field was calculated from these values.

Exposure 2

Main characteristics

Frequency	835 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2, 4, 6, 8, 12, 16, and 24 h

Modulation

Modulation type	AM
Modulation frequency	16–60 Hz
Modulation depth	23 %
Additional info	sinusoidal, 16 or 60 Hz

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	0.96 W	-	-	-	-
electric field strength	0.6 V/cm	mean	calculated	-	-
SAR	2.5 W/kg	mean	measured	-	-

Exposure 3

Main characteristics

Frequency	835 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 8 h

Modulation

Modulation type	AM
Modulation frequency	6–600 Hz
Modulation depth	23 %
Additional info	sinusoidal: 6, 16, 55, 60, 65, or 600 Hz

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	0.96 W	-	-	-	-
electric field strength	0.6 V/cm	mean	calculated	-	-
SAR	2.5 W/kg	mean	measured	-	-

Exposure 4

Main characteristics

Frequency	835 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 8 h

Modulation

Modulation type	AM
Modulation depth	23 %
Additional info	modulation with speech from a radio receiver

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	0.96 W	-	-	-	-
electric field strength	0.6 V/cm	mean	calculated	-	-
SAR	2.5 W/kg	mean	measured	-	-

Exposure 5

Main characteristics

Frequency	835 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2, 4, 6, 8, 12, and 16 h

Modulation

Modulation type	FM
Modulation frequency	60 Hz
Additional info	sinusoidal, ±60 kHz deviation, wideband FM

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	0.96 W	-	-	-	-
electric field strength	0.6 V/cm	mean	calculated	-	-
SAR	2.5 W/kg	mean	measured	-	-

Exposure 6

Main characteristics

Frequency	835 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 8 h

Modulation

Modulation type	pulsed
Duty cycle	50 %
Repetition frequency	50 Hz
Pulse type	rectangular

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	0.96 W	-	-	-	-
electric field strength	0.6 V/cm	mean	calculated	-	-
SAR	2.5 W/kg	mean	measured	-	-

Exposure 7

Main characteristics

Frequency	840 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 4, 6, 8, and 10 h

Modulation

Modulation type	FM
Additional info	AMPS analog cellular phone signal with continuous transmission of a pseudorandom test sequence. The output signal was found to be constant (i.e., no amplitude modulation).

Exposure setup

Exposure source	cellular phone TEM cell

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	0.96 W	-	-	-	-
electric field strength	0.6 V/cm	mean	calculated	-	-
SAR	2.5 W/kg	mean	measured	-	-

Exposure 8

Main characteristics

Frequency	840 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 4, 6, 8, 10, and 16 h

Modulation

Modulation type	pulsed
Pulse width	7 ms
Duty cycle	30 %
Repetition frequency	50 Hz
Additional info	D-AMPS digital cellular phone signal with continuous transmission of a pseudorandom test sequence. TDMA with bursts lasting approx. 7 ms.

Exposure setup

Exposure source	cellular phone TEM cell

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	0.96 W	-	-	-	-
electric field strength	0.6 V/cm	mean	calculated	-	-
SAR	2.5 W/kg	mean	measured	-	-

Reference articles

Litovitz TA et al. (1993): The role of coherence time in the effect of microwaves on ornithine decarboxylase activity

Exposed system:

intact cell/cell culture
murine L929 fibroblast cells

Methods Endpoint/measurement parameters/methodology

cell function: enzyme activity of ornithine decarboxylase (measurement of ¹⁴CO₂ release)

Investigated system:

cell lysates

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The observed changes in the activity of ornithine decarboxylase depend on the type of microwave modulation which were used. Amplitude-modulated microwaves are capable of altering the enzymatic activity, whereas frequency-modulated microwaves appear to have no effect.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Department of Defense (DoD), Department of the Army, USA

Replication studies

Billaudel B et al. (2009): Effects of exposure to DAMPS and GSM signals on ornithine decarboxylase (ODC) activity: I. L-929 mouse fibroblasts
Höytö A et al. (2007): Ornithine decarboxylase activity of L929 cells after exposure to continuous wave or 50 Hz modulated radiofrequency radiation--a replication study

Billaudel B et al. (2009): Effects of exposure to DAMPS and GSM signals on ornithine decarboxylase (ODC) activity: I. L-929 mouse fibroblasts
Billaudel B et al. (2009): Effects of exposure to DAMPS and GSM signals on ornithine decarboxylase (ODC) activity: II. SH-SY5Y human neuroblastoma cells
Hoyto A et al. (2008): Radiofrequency radiation does not significantly affect ornithine decarboxylase activity, proliferation, or caspase-3 activity of fibroblasts in different physiological conditions
Höytö A et al. (2007): Ornithine decarboxylase activity of L929 cells after exposure to continuous wave or 50 Hz modulated radiofrequency radiation--a replication study
Höytö A et al. (2007): Ornithine decarboxylase activity is affected in primary astrocytes but not in secondary cell lines exposed to 872 MHz RF radiation
Höytö A et al. (2006): Modest increase in temperature affects ODC activity in L929 cells: Low-level radiofrequency radiation does not
Desta AB et al. (2003): Non-thermal exposure to radiofrequency energy from digital wireless phones does not affect ornithine decarboxylase activity in L929 cells
Litovitz TA et al. (1997): Bioeffects induced by exposure to microwaves are mitigated by superposition of ELF noise

Role of modulation on the effect of microwaves on ornithine decarboxylase activity in L929 cells 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

Exposure 6

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 7

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 8

Main characteristics

Modulation

Exposure setup

Parameters

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

Replication studies

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