Column 3: Dec 1998
Readers are probably familiar
with the idea of electrophoresis, although they may not know the term.
The technique is used for DNA fingerprinting to determine paternity.
In television documentaries we
often see forensic scientists holding a small X-ray film with lines of
bar-codes. These bars are the physical locations of the genetic material
after the DNA strands have been chemically separated, broken up and
dragged through a viscous gel towards an anode. The bars mark the
cumulative lodging place of many identical DNA pieces from many
different cells.
We have the same DNA in every
cell of our bodies, and DNA molecules are negatively charged. Each piece
has a different physical resistance, so these bars mark the cumulative
lodging place of many identical DNA genetic parts.
During the years of childhood and
growth cells are constantly dividing and duplicating by a process called
'mitosis', so it is especially important that the DNA replicates
accurately and that the gene sequences remain in order; these two-metre
helical strands of paired molecules contain the basic blueprint for
constructing and maintaining viable life.
There are 50,000 billion cells in
the body, and even in older people the body is still actively creating
another billion new cells every hour, so the incorruptibility of DNA is
all-important in our health and survival.
Despite this constant manufacture
of new cells, we don't keep growing in size after adulthood. A few die
from normal wear and tear ('necrosis') but, to maintain the balance, mis-copied
or unwanted cells are instructed to suicide ('apoptosis') by the cells
nearby.
Programmed cell death is an
essential part of life, and, if this euthanasic message fails to trigger
suicide and the cell goes into a phase of uncontrolled division, tumours
and cancers result.
The cells of the heart muscle,
and those of the nerves and brain neurones don't replicate, but all
others are reproducing regularly over your lifetime. So at the
molecular-cell level there's a new you about every five years.
This raises the question: Why do
we get cancer? Cancer is slow in onset; it generally takes between ten
and twenty years to incubate. Why do we get it at all if most cells are
only five years old?
Obviously the defects which cause
uncontrolled cell growth are often (but not always) transmitted from
mother-cells to daughter-cells during mitosis. Defects like these are
called 'mutations' Ñ however, not all mutations are disruptive or
dangerous to our health. DNA in our cells constantly comes under attack
from many sources, and the normal body processes ignore or handle most
of the defects.
External messages are also
transmitted across cell boundaries and between cells to initiate
apoptosis (programmed cell death), but these may similarly be
short-circuited or distorted in some way. These messages are carried by
electrically-oriented flows of ions and by more complex protein and
enzyme molecules.
The point is, that at the
molecular level, humans cell functions are very dynamic, very
regenerative, constantly being disrupted and repaired, highly tolerant
of defects, and very much affected by electrical influences.
Recently the biomedical
researchers have begun using a technique similar to DNA fingerprinting
to investigate damage to DNA. This is called single-cell gel (SCG)
electrophoresis or 'comet assay', and it is capable of finding defects
in single cell exposed to toxic chemicals or ionising radiation.
Our interest here is in whether
this technique can detect damage to cell functions or DNA viability from
low level radio waves. Classical radio theory says radio waves can't
damage molecules, because their energy is not sufficient to break
chemical bonds.
The technique gets its name from
the comet-and-tail appearance which results from broken genetic material
being dragged through the gel by electrical attraction ahead of the
more-resistant DNA bundles.
Think of this as towing a very
old car through a few miles of deep mud, then counting the bits and
pieces that fall off in the process. But here the car (the DNA ball)
drags behind and the broken bits move out ahead.
Fig.1 Unexposed control. The bundle is simply DNA.
Fig.3 X-ray calibration: After 25.6 rads.
DNA strand breaks are now very obvious.
Figure 2 and 3 shows the comets
from immune cells which were subject to various levels of X-rays
exposure for calibration purposes. This sequence establishes the fact
that the breaks in the DNA are dose-related: higher exposures produce
more and therefore longer and more complex comet tails.
Comet assay techniques were
developed by Swedish scientists Östling and Johannson in 1984, and then
later refined by Narendra Pal ('NP') Singh in 1988 (with other
improvements later). At that time Dr Singh was a research scientist at
the US National Institute on Aging.
Chemical processes are employed
to digest and remove all the lipids and proteins from the cell to
express the DNA breaks, and Singh's alkaline separation techniques are
now widely recognised for their sensitivity and reliability. Alternative
'neutral' approaches are applied also in some research laboratories.
Comet assays reveal damage to DNA
from air and water pollution, food additives, diet and smoking, etc. and
they always require very highly developed laboratory skills and strict
attention to detail. Unfortunately they lack a recognised form of
objective measurement.
Back in 1994, Singh joined
biomedical scientist Dr Henry Lai at the Bioelectromagnetics Research
Laboratory, University of Washington in Seattle. The work originally
conducted at this university was funded by the US Navy and Air Force,
but that source of funding has long evaporated. Under Henry Lai, the US
government's National Institutes of Health has been responsible for most
of the funding.
In a
ground-breaking series of experiments between 1994 and 1998 they
demonstrated convincingly that moderate levels of microwave (2.45GHz)
radiation, for exposures of only two hours, could increase the frequency
of single-strand DNA breaks in the brain cells of live rats.
Fig.4 Assay showing effect of 2 hrs of microwave exposure (2.45GHz) at a
SAR (absorption) level of 0.6 W/kg [about cellphone handset levels] DNA
strand breaks are also obvious.
These images result from
fluorescent molecules attached to the end of each DNA strand at a break
point, and so are best seen in the negative.
Figure 4 was captured by Drs Lai
and Singh, and it shows the results of a comet assay at power densities
about one-fifth those previously thought to cause adverse biological
effects. These exposures were only for a short time, and they used radio
power-densities well below those said to be 'ionising' (having the power
to break chemical/material bonds).
In this research, Drs Lai and
Singh have used microwave frequencies which are higher than cellphones
(at 0.9GHz), but not much above those used by the cellphone cousins, the
new handheld PCS phones (1.9GHz).
DNA strands tend to break all the
time, but they repair themselves constantly, so these comet-tail images
need to be compared with the unexposed control DNA bundle in Figure 1.
The cell bundles in Figure 4 have the classic comet tail of particles
indicating extensive DNA damage, well above the spontaneous DNA damage
levels of the controls.
Spontaneous breaks in the DNA are
relatively common in all cells (6.00-radical attacks seem to be
responsible) and most are quickly repaired by normal cell processes --
generally within minutes or hours. But any form of increased disruption
to the DNA is worrying.ÊNerve cells in particular have a low capability
for DNA repair and so the effects of additional breaks could accumulate.
The DNA strands form a
spiral-staircase-like helix, and so breaks on only one side of the
ladder are much easier to repair than those where both sides are broken.
But in later experiments Lai and Singh found double-strand DNA breaks
after similar exposures times and levels.
It is possible for the cell to
make mistakes when repairing single-strand breaks, but the likelihood of
serious mistakes (mutations) increases substantially with double-strand
breaks.
Fortunately, only certain genes
are 'expressed' (activated) within each organ, so less than one percent
of the DNA is essential in any one cell. Most mutations will cause no
harm, and those that are very disruptive will probably lead to
programmed cell death.
This introduces a paradox; small
problems accumulating over time may be more dangerous than large
defects. Cells that suffer gross disturbances to their critical genes
are also more likely be programmed to suicide; therefore the larger DNA
disruptions may be self-annihilating.
Over the years the DNA in human
cells constantly suffer attack, some of which is never repaired. Given
enough time, the accumulation of minor (but jointly critical) problems
can cause cancer to develop. There is rarely a single cause of cancer.
This is also why cancer is a
mostly a condition of age. It's probably that older people have many
pre-cancerous cells, even though only a few suffer the critical
mutations that lead to uncontrolled cell proliferation. These are just
the straws that finally broke the camel's back.
This raises the distinct
possibility that cumulative low level RF exposures could be more harmful
than higher critical exposures.
And since nerve cells don't
divide and proliferate, this damage could equally contribute to
degenerative diseases such as Parkinson's and Altzheimer's. Cancers and
age-associated degenerative conditions may be closely related.
Another aspect of the Lai-Singh
research (with pulsed microwave similar to GSM cellphones and radar) was
also disturbing. Rat brains which were excised and prepared quickly for
the assay showed fewer breaks, while those which were checked four hours
after exposure revealed much higher levels. This suggests that both the
damage and the repair-initiation are not simple and immediate processes,
and supports the thesis that DNA damage from repeated uses of a
cellphone could be cumulative.
Dr Jerry Phillips, working in a
research facility outside Los Angeles, made a similar finding. His
research showed that DNA breaks actually decreased in some RF exposure
conditions, sometimes with different wave-forms, suggesting that there's
a more complex causal link than expected, and a delicate balance between
the break and repair-rates.
Phillips work also suggests that
there may be some type of rough feedback control mechanism -- something
like a sticky fly-wheel governor on a steam boiler which makes the
engine-rate hunt between slow and fast. The DNA-repair feedback might
lead to mistakes and mutation and increase the chance of destructive
cancer.
This work is highly
controversial, as you'd imagine. Lai and Singh have reported finding of
DNA strand breaks at levels of only one-fifth the American RF safety
limits -- but they've since also found that they can use the pineal
hormone melatonin and other anti-oxidants to countering the RF effect.
So the research is not only producing negative results.
This points to the importance of
6.00-radicals as the intermediary which actually damages the DNA, which
doesn't come as a surprise to most researchers. 6.00-radicals have often
been implicated in DNA problems.
Although the Lai-Singh research
hasn't been faithfully replicated, other scientists have found similar
DNA strand breaks in parallel radio research projects, and a number of
live-animal tests have confirmed increased tumour rates resulting from
long exposures over the life of the animals. There is also evidence that
radio-wave exposures can influence the short term memory.
Currently, the Lai-Singh research
has been stymied for lack of funding from the US government which has
its attention focussed on other matters, while the cellular phone
industry has preferred to invest in less disturbing projects.
END
