A study of the effects of RF radiation on blood flow in the brain
A recent publication reported on the effects of radiofrequency radiation, emitted by a mobile phone, on blood flow in the human brain. The blood flow was measured by a PET scan. The subjects were examined while performing a memory task. While there was a relative decrease in regional blood flow in the part of the brain associated with hearing, it was thought that this was likely due to an auditory signal from the battery of the active mobile phone, rather than to the EMF from the phone. There was no change in the brain area most likely to be exposed to radiation.
A previous study of brain blood flow, by Huber and colleagues, which was reported in "What's New" in February 2003, showed increased blood flow in the brain on the same side as exposure to a pulse-modulated electromagnetic field.
For more, see "Research
- Clinical - Cognitive function".
No effect of RF radiation on melatonin production in rats
Two previous studies, by Vollrath and colleagues (1997) and Heikkinen and colleagues (1999), showed no effect of exposure to RF radiation on melatonin production in laboratory animals. Another study has shown similar results. Bakos and colleagues exposed the animals to either 900 or 1800 MHz frequency radiation for 2 hours a day for 14 days, and found no change in the amount of urinary melatonin produced during the night. Most studies in humans have failed to show any effect of RF radiation on melatonin production. These results are of particular interest because some researchers have speculated that disturbed melatonin production may influence cancer formation. For more, see "Research - Toxicological Experiments - Others" and "Research - Clinical experiments - Hormone secretion".
Bakos J, Kubinyi G, Sinay H, Thuróczy G (2003): GSM modulated
radiofrequency radiation does not affect 6-sulfatoxymelatonin excretion
of rats. Bioelectromagnetics 24:531-534.
In March 2003 "What's New" we reported a study by Mashevich and colleagues that suggested that RF radiation can induce changes in chromosomes of cells. In the latest issue of the journal "Bioelectromagnetics" there is correspondence about the validity of the findings. The debate centres on whether or not the cells could have been exposed to excessive heating.
References: Chou C-K, Swicord M (2003): Comment on "Exposure of human peripheral blood lymphocytes to electromagnetic fields associated with cellular phones leads to chromosomal instability" by Mashevich et al. Bioelectromagnetics 2003;24:582.
R, Barbul A (2003): Reply to the Comment. Bioelectromagnetics 24:583-585.
The US government has announced plans for a $10 million study of potential health risks associated with cell phones.
It has also been
reported that the Danish Minister of Science and Technology is planning
a new study into the relationship between radiation given off by cell
phones and possible health effects.