IP: New Scientist Special Investigation: Mobile Phones

[Dave Farber <farber () cis upenn edu>]

From: Mike Pollock <pheel () sprynet com> 
Subject: New Scientist Special Investigation: Mobile Phones 
Date: Tue, 13 Apr 1999 11:50:38 -0400

GET YOUR HEAD ROUND THIS...
By David Concar
Forget the hype--there's still no evidence that mobile phones 
will mangle your memories or give you cancer. But the microwaves they 
emit must be up to something. Meet the fast-growing worms and boozing 
rats that have the experts baffled...and discover why a phone call 
might make you quick on the draw.
FOR ANYONE WHO USES a mobile, these are worrying times. "Mobile 
phone killed my man," screamed one headline last year. In February 
came claims that an unpublished study had found that cellphones cause 
memory loss. And last month, a British tabloid devoted its front page 
to a picture supposedly showing how mobiles heat the brain.
But speak to the scientists whose work is the focus of these 
scares and you hear a different story. First, there is no evidence 
that mobiles cause cancer or any other illness in people. You can also 
forget about mobiles "cooking" your brain--a mild bout of exercise 
will heat your head more than the puny microwaves that the devices 
emit. And finally, the study fuelling the latest claims about mobile 
phones scrambling the mind in fact shows nothing of the kind.
What we do have, however, are some tantalising results 
suggesting that cellphones' emissions have a variety of strange 
effects on living tissue that can't be reconciled with conventional 
radiation biology. And it's only when the questions raised by these 
experiments are answered that we'll be able to say for sure what 
mobiles might be doing to your head.
One of the weirdest effects comes from the now famous "memory 
loss" study, published this week in the International Journal of 
Radiation Biology (vol 75, p 447). Alan Preece and his colleagues at 
the University of Bristol clamped a device that mimicked the microwave 
emissions of analogue or digital mobile phones to the left ear of 
volunteers. Contrary to the press reports that appeared in February, 
the volunteers were as good at recalling words and pictures they had 
been shown on a computer screen whether or not the device was switched 
on. Preece says he still can't comment on the effects of using a 
cellphone for years on end. But he rules out the suggestion that 
mobiles have an immediate effect on our cognitive abilities. "I'm 
pretty sure there is no effect on short-term memory," he says.
But the microwaves did have one completely unexpected effect: 
they decreased the time subjects took to react to words flashed onto 
the screen. When "yes" or "no" was displayed, the volunteers were 
quicker at pressing a matching button if the headset was switched 
on. The improvement was small--about 4 per cent when the device was 
set to mimic an analogue phone--but unlikely to be a freak finding, 
because it was seen in two groups of volunteers.
This seems like good news. But if microwave emissions can 
influence reaction times as they pass through the skull, what else 
might they be doing?
It's a good question, because in theory mobile phone emissions 
shouldn't do anything to living tissues (see "Explaining the 
inexplicable", p 23).
Preece speculates that the improvement in reaction times is 
caused by microwaves somehow speeding the flow of electrical signals 
through an area of the cerebral cortex known as the angular gyrus, 
which connects brain areas involved in vision and language. But he has 
no idea why this should happen.
This finding joins a growing list of unexpected effects ascribed 
to mobile phone emissions. Some of the most intriguing results come 
from David de Pomerai and his team at the University of 
Nottingham. They have been beaming microwaves at tiny nematode worms, 
chosen because their developmental and cell biology are well 
understood.
In one series of experiments, the team found that larvae exposed 
to an overnight dose of microwaves wriggled less and grew 5 per cent 
faster than larvae that were not exposed, suggesting that the 
microwaves were speeding up cell division.
The researchers now intend to examine mammalian cells to see if 
they divide more rapidly when exposed to microwaves--a finding that 
would raise fears about cancer. But de Pomerai insists that there is 
no reason to panic about the nematode data. "As a proportion of life 
span, exposing a nematode worm to microwaves overnight is like 
exposing a human continuously for an entire decade," he says.
De Pomerai is also trying to work out how microwaves could 
affect nematode biology. He already has evidence that "heat shock" 
proteins are produced in the exposed worms' cells. Despite their name, 
heat shock proteins are produced by cells in response to many kinds of 
stress that damage proteins, not just excessive heat. The heat 
generated by the microwaves in de Pomerai's experiments was too low to 
stimulate their production, so he believes microwaves do something 
else that induces stress.
Support for the idea that microwaves can trigger biochemical 
stress at low energies comes from a team led by Henry Lai at the 
University of Washington in Seattle. He claims that rats exposed to 
microwaves produce natural painkillers called endorphins and are more 
likely to binge on alcohol or react strongly to morphine and 
barbiturates. His team also has evidence from rats that exposure to 
microwaves unleashes corticotropin releasing factor, a stress hormone, 
and disrupts the ebb and flow in the brain of acetylcholine, a 
neurotransmitter involved in memory and alertness, among other things.
According to Lai, the changes are similar to those in rats 
exposed to stressful blasts of white noise and help to explain why 
rats exposed to microwaves take longer to learn the position of a 
submerged platform in cloudy water--another of his findings.
Well known for his outspoken views about the hazards of mobile 
phones, Lai concedes that he has no evidence to suggest people have 
problems handling alcohol or remembering where they are following a 
phone call. Yet he argues that mobiles should sometimes be switched 
off as a precaution--by aircraft technicians performing 
safety-critical maintenance work, for instance.
Last year, fears about mobiles affecting brain function received 
fresh impetus thanks to work by John Tattersall and his colleagues at 
the Defence Evaluation and Research Agency's labs at Porton Down in 
Wiltshire. Tattersall exposed slices of rat brain to microwave 
radiation. He found that it blunted their electrical activity and 
weakened their responses to stimulation. Because the brain slices were 
taken from the hippocampus, a structure with a role in learning, the 
results were seized upon as further evidence that mobile phones could 
scramble human memories.
Mixed messages
In fact, the implications are far from clear. In people, the 
hippocampus is buried too deep in the brain to be influenced by 
emissions from mobile phones, says Tattersall. And his latest findings 
have undermined fears about memory loss. One result, for instance, 
suggests that nerve cell synapses exposed to microwaves become 
more--rather than less--receptive to undergoing changes linked to 
memory formation.
Taken together, the available data are very difficult to 
interpret. And some scientists suspect they may not even be 
reproducible. John Moulder, a radiation oncologist at the Medical 
College of Wisconsin in Milwaukee, says these experiments tend to work 
in one lab but fail in others, suggesting that technical glitches 
could be responsible for the results.
Perhaps the best reason for remaining sceptical is that the most 
worrying discovery ever made about low-energy microwaves remains mired 
in controversy four years after it was reported. In 1995, Lai claimed 
the DNA from the brains of rats exposed to microwaves suffered 
numerous strand breaks, a type of damage often seen in cells exposed 
to cancer- causing chemicals or powerful X-rays.
"If it was right, it would completely change the way we think 
about radiation," says Joseph Roti Roti, a radiation oncologist at 
Washington University in St Louis, Missouri. But so far, Roti Roti's 
team--funded by the mobile phone giant Motorola--has been unable to 
repeat the finding. Neither has Luc Verschaeve at the Flemish 
Institute for Technological Research in Boeretang, who has exposed 
white blood cells to microwaves.
In 1997 came another bombshell that is now being called into 
question. Researchers at the Royal Adelaide Hospital in Australia 
spent 18 months exposing mice to radiation mimicking the emissions of 
digital mobile phones. Michael Repacholi, who coordinated the study, 
didn't expect to find anything untoward. Yet twice as many of these 
mice developed lymphomas as did animals not exposed to the radiation.
Cancer conundrum
But since then, three other teams have failed to find similar 
evidence of increased cancer rates among mice exposed to microwave 
emissions. To increase the sensitivity of the experiment, Repacholi's 
team used mice that had been genetically engineered to be susceptible 
to lymphoma. In the latest study, a team of microwave experts at the 
Brooks Air Force Base in San Antonio, Texas, used mice genetically 
engineered to be susceptible to breast tumours. They exposed the 
animals to microwaves for 20 hours a day for 18 months, yet saw no 
increases in tumour rates.
Repacholi, who is now coordinating the WHO's research into the 
health effects of electromagnetic radiation, says he is reserving 
judgment about the cancer link until researchers in Australia have 
repeated the original experiment using the same strain of mice and 
exposure conditions. "If they don't come up with the same result, 
that'll be a happy outcome," he says.
An even happier outcome would be if microwaves turned out to be 
good for you. It sounds crazy, but a couple of years ago a team led by 
William Ross Adey at the Veterans Affairs Medical Center in Loma 
Linda, California, found that mice exposed to microwaves for two hours 
a day were less likely to develop brain tumours when given a 
cancer-causing chemical.
But nobody has yet replicated that finding either, and Moulder 
doubts anyone will. He believes that what we're seeing is the 
variation from lab to lab that you would expect from technically 
demanding experiments that are trying to pick up tiny effects. "Study 
something enough times and by the laws of statistics you'll 
occasionally see something," he says.
Some of the experiments may also be plagued by systematic 
errors. One problem is that microwave emissions can interfere with 
electrodes and other instruments, leading to all manner of false 
readings. Another is that researchers often have a hard job ensuring 
their equipment doesn't induce heating effects that could never be 
caused by a mobile phone.
So should we forget about mobile phone radiation causing brain 
tumours and scrambling our minds? "If it doesn't reliably cause cancer 
in animals and cells at high doses, then it probably isn't going to 
cause cancer in humans," says Moulder. And while the results on the 
activity of the brain are too new to have been subjected to the same 
scrutiny, the consensus is: don't panic . . . but watch this space.
from New Scientist, 10 April 1999