“Mechanism of Electromagnetic
Field Interactions with Cells”
This was the topic of a presentation by Dr Martin Blank from Columbia University
that he gave at the CSIRO Division of Applied Physics at Lindfield on 23 August
1996.Dr Blank is a founding member of the Bioelectrochemical Society. He was
reporting some recent findings from his research concerning the effect of
power frequency electric fields on body tissues. The following is a summary
by Don Benjamin of Dr Blank s talk.
He said he was impressed by the cross disciplinary work carried
out at Cambridge when he visited there and was working on colloidal science.
He has always remembered this and his present work relies heavily on this interdisciplinary
exchange of information.
There is wide agreement in the scientific community on the damage and
cancer- causing effect of radiation in the ionising region of the electromagnetic(EM)
spectrum; i.e. > 10^15 Hertz, or above in the ultraviolet region. There
is no such agreement in the lower or non-ionizing region. The question
is does such EM radiation cause cancer? and if so, how?.
Recent controversies have occurred about cellular phones. In the US Larry
King is suing Motorola following his wife s diagnosis with a brain tumour
that he attributes to mobile phone use. Anecdotal evidence suggests higher
incidence of brain cancers among mobile phone users. Is it real?.
The heating effect of microwaves on tissues is known. Is the effect still
there and damaging as much lower, say, milligauss levels?.
Video display monitors emit EM radiation at about 10^4 Hz. This is mainly
in the side fields. Laptop users are spared this particular hazard but
their hard drive emits some radiation.
His work centres on the 50-60 Hz end of the spectrum.
Electricity power lines have an electric field gradient of about 10^3
V/m in the air below the lines but because of the attenuation effect at
the skin (about 10-7) it is considered that this is unlikely to produce
a significant effect within the body. The magnetic field does penetrate
the body unimpeded. So this is likely to be the more important effect.
Evidence from early epidemiological studies (by Wertheimer and Leiper?)
first suggested an increased level of leukemia among children who lived
near power lines, the risk being elevated by a factor of about 2-3 times.
A threshold level of about 2 milligauss was suggested. This study was
ridiculed at the time, particularly by the electric power utilities on
the grounds of poor methodology.
The New York electric power authority (Savitz) later repeated this study
with better methodology an reached the same conclusions. Later studies
in Los Angeles and Sweden replicated these results for childhood leukemia.
Another series of studies found an increased risk of breast cancer among
telephone linemen of about 5-7 times. Since breast cancer is very rare
in males such an increased risk was very interesting.
Evidence of the effect of EM radiation from the medical area has resulted
in the US FDA approving therapies involving the use of EM radiation to
promote bone healing following fractures. It is now accepted that magnetic
fields can accelerate growth.
So what is the mechanism?.
The hypothesis offered is one of biosynthesis involving the formation
of new chemicals affected by weak electromagnetic fields, probably magnetic
If one considers the living cell as having a diameter of about
10 micrometers and subjected to a magnetic field the effect is one of an increase
in the rate of protein production, including enzymes. One way this appears to
happen involves a two stage process involving transcription and translation.
In the transcription stage the DNA unravels partially forming messenger
RNA, (mRNA) that goes out of the DNA nucleus and latches onto the ribosomes
in the cell fluid surrounding the DNA nucleus. In the second stage the
protein is produced. There is also a feedback mechanism that controls
how much of the protein enzymes are produced, depending on the body s
needs. If one measures the rate of protein production or the enzyme activity
with and without the presence of the magnetic field it is found that the
activity increases in the presence of the EM field.
There is a known mechanism, formerly known as heat shock, whereby a cell
produces extra protein/enzymes in response to shock such as thermal shock.
These proteins are called heat shock proteins (HSPs). This is now referred
to as a stress response rather than heat shock because the process apparently
applies to any stress, not only thermal. EM radiation appears to be merely
another form of stress on the cell.
One interesting result is that the response from increasing the magnetic
field in a cell from 8 milligauss to 80 milligauss is similar to the effect
of increasing the temperature from 37 deg C to 42 deg C.
Another interesting effect is the stress tolerance. When a cell has its
temperature raised from 37 deg C to 45 deg C the cell will die within
a few minutes. But if the cell s temperature is raised first to about
42 deg C, allowed to fall back to 37 deg C then raised to 45 C the cell
doesn t die, as if the memory of the previous stress has conditioned the
cell to cope with more stress than before.
There also appears to be a negative feedback mechanism operating whereby
the HSPs reduce the rate of production of further HSPs. What are the implications
for these effects with EM radiation? Does this mean that people subjected
to continuous or occasional low level EM radiation are more able to tolerate
further EM radiation?.
What is happening at the molecular level? It appears that the process
is one affecting the Sodium Potassium Adenosine Triphosphatase (Na-K-ATP-ase)
pump that drives the cell.
Consider a continuous cell membrane (phospho-lipase). There are molecules
that cross the membrane with one particular pear-shaped one having its
narrow end extending beyond the outer edge of the membrane and its broader
end extending beyond the inner edge. This is the larger of a two-part
molecule; the pear-shaped one is accompanied by a smaller elliptical
part. Most of the interesting characteristics of the molecule occur
in the part.
For this 100,000 molecular weight cell the ATP converts to ADP with the
production of 3 Na+ ions and 2 K+ ions.
It is the business of these enzymes to use the energy from the ATP to
get the Na to move out of the cell and the K to move inside. It appears
to do this by modifying the permeability of the cell walls to allow these
interchanges. This enzyme activity appears to be related to the movement
of electric charge e-. Thus the movement of these positive ions through
the is probably mediated by the movement of these negative charges and
the amount of activity enhancement depends on the availability of these
The enzyme activity is enhanced for magnetic fields at all enzyme activities
but for electric fields is limited to low enzyme activity.
Any electric field present does not permeate the membrane. Instead it
builds up a +ve charge on the outer layer of the membrane. Its ability
to produce a corresponding -ve charge on the inner surface of the membrane
relies on the scavenging of free charges within the membrane. So this
enhancing effect is limited to low enzyme activities presumably because
of the limitation of the availability of sufficient free charges within
The quantity of charge/current density involved is quite large being
equivalent to currents in a conductor of about 10,000 amperes; perhaps
Summary (as written by Dr Martin Blank).
Interest in biological effects of electromagnetic (EM) fields continues
to be stimulated by epidemiological studies that correlate increased risk
of certain cancers with environmental EM field exposures. Correlations
suggest causality, but many scientific questions about cellular mechanisms
and signal transduction processes must be answered to assess the plausibility
of the risk. Our studies of EM field interactions with cells provide significant
insights into both the cell biology and the cell biophysics of the problem.
From analyzing changes in the biosynthesis following exposure to EM fields,
we have shown that EM fields stimulate the stress response, a cellular
reaction to a variety of stimuli that cells interpret as harmful.
From studies of electric and magnetic signal transduction processes in
a functioning membrane protein, the Na, K-atpase “ion pump” in cells,
we have found that signal transduction always depends upon biological
activity of the enzyme. Furthermore, the different effects in electric
and magnetic fields can be explained by interaction of the field with
moving charges during enzyme activity. This mechanism suggests that EM
field-stimulated initiation of the stress response may involve direct
interaction with DNA.
The systems studied are not esoteric or under unusual conditions.
both biological systems are present in virtually all cells and the measured
effects occur in the power frequency range and at EM field levels that are slightly
above normal background.