Forschungsgemeinschaft Funk e.V.

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Edition No. 20/E December 2003
In vitro studies on biological effects of radiofrequency fields
between 1997 and 2002
Prof. Dr. Rainer Meyer
Physiological Department University of Bonn, Wilhelmstr. 31, D-53111 Bonn

After more than ten years of mobile phone distribution of the GSM standard (D and E nets), there is still doubt in the general population regarding the harmlessness of this technology to health. Consequently, in recent years numerous studies on effects from mobile radio high-frequency fields - HF fields - on the organism have been performed; a trend continuing to present. The aim of this survey is to present studies from the years 1997 to 2002 conducted in isolated organs, tissues, or cells, so-called in vitro studies. For a better understanding of this issue, the many available studies from the recent past were classified according to the steps of tumor initiation. This classification was based upon a 2002 epidemiological study describing an association between long-term application of many years of analogue mobile phones and brain tumor initiation.

Very often, the first step of tumor initiation is a mutation in the genome (alteration of genetic material) of a cell. Radioactive radiation will generate such alterations with a certain probability. Though HF fields cannot lead to the same results, they have repeatedly been suspected of doing so. A solid majority of the numerous investigations into this issue showed negative results irrespective of the applied method, used cell types or test parameters. In 1996 and 1997, several studies performed in the rat brain received a lot of attention, however they could neither be reproduced by other working groups nor be confirmed by similar test approaches. Neither the idea of HF fields potentially intensifying mutagenic effects of chemical substances could be verified. To the contrary, even earlier positive results of a Belgian working group found in lymphocytes could not be confirmed when using refined test approaches.

The second step of tumor initiation, unrestricted cell division, can occur when the damaged genes are transcribed and translated into proteins. The occurrence and the control of these processes is dependent on many signaling systems. Thus, the information on investigations into different cellular signaling systems is summed up in one chapter. One important signaling system performing varied tasks is the alteration of intracellular calcium concentration. However, evidence for an effect from HF fields was found neither in cardiac muscle cells nor in lymphocytes.

Proto-oncogenes are genes which often are activated by stress or cell division. They also are more strongly expressed in denaturized cells. They can be transformed into oncogenes by slight mutations which can lead to unrestricted division of a cell. Proteins developing during proto-oncogene transcription often are signal molecules. The survey presents both in vitro studies as well as animals tests since only joint presentation enables us to provide a useful overview. According to the relevant studies, effects on proto-oncogenes from HF fields seem to be principally possible. However, these HF field effects regularly occur only at SARs in the thermal range, i.e. above limit values.
When cells divide, previously certain molecules have been synthesized. The activitiy of the enzyme ornithine decarboxylase is seen as a marker of this process. Therefore, a working group performed a series of experiments examining the influence of HF fields on this enzyme. Results indicate a susceptibility of this enzyme to HF fields. The results were never reproduced by others, though. Moreover, the respective working group did not follow up on this issue. However, cell division rates at HF field exposure were examined for many different cell types without finding evidence for a field influence.

The next step of cancerous diseases, the development of metastases, is very complex depending on very many control signals. In the corresponding paragraph, studies on heat-shock proteins and on the blood-brain barrier are summed up. Blood-brain barrier permeabilization potentially is favored by heat-shock proteins making cell transport through the blood-brain barrier easier. Heat-shock protein development as a protection mechanism is increased after exposure to high temperatures or other stressors.

Consequently, it has been hypothesized that the synthesis of these proteins could also be triggered by HF fields. At SARs distinctly above limit values, different systems showed HF-dependent heat-shock protein development. One study performed in cultivated endothelial cells should especially be mentioned in this context, since an induction of heat-shock proteins was shown at SARs close to the limit value. Endothelial cells provide the lining of blood capillaries and thus are part of the structure of the blood-brain barrier. Though another working group also could find an induction of heat-shock proteins, differences between the two investigations are so big that they do not reinforce each other's results.

For investigating the blood-brain barrier itself, several working groups performed animal tests. Only one of the investigations could - even if repeatedly - prove a permeabilization of the blood-brain barrier at exposure to different HF fields in a rat model. An in vitro cell culture model of the blood-brain barrier showed the same effects. However, to date these can only be seen as single findings.
The studies referred to do not indicate health dangers from HF fields as are used by mobile radio.

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