Subject: (Curry) Re How important is the "mechanism?".... (fwd)
Date: Mon, 6 Jul 1998 122219 -0500 (CDT)
From: "Roy L. Beavers" <rbeavers@llion.org>
To: emfguru@hotmail.com
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---------- Forwarded message ----------
Date: Sun, 05 Jul 1998 20:57:26 -0600
From: "Bill P. Curry"
To: "Roy L. Beavers"
Subject: Re: How important is the "mechanism?"....
Roy,
I think there has been some misunderstanding of the importance I put on
mechanisms. In the case of biological damage by EMF sources, I think there is
a logical sequence in which different investigative procedures can complement
each other. Usually, epidemiological data are the first to suggest a link
between some causative agent (such as EMF) and a resultant health effect. At
some point laboratory studies (perhaps guided by a theoretical model, but not
necessarily so) are invoked to try to isolate some paths by which the agent
causes biological damage. When enough data from these studies have been
obtained and enough modeling studies have been attempted, usually one can
postulate a damage mechanism and devise suitable experimental tests of that
mechanism. The advantage of having established a damage mechanism is that one
can model the process in quantitative terms. Having so done, one can then
determine "safe" levels of radiation - either by itself, or in the presence of
other causative agents.
I think the historical case against smoking demonstrates some aspects of this
sequence of events. The link between smoking and health was discovered in
epedemiological studies, but these studies were followed by microscopic tissue
examinations that showed damage to lung tissue and other organs in chronic
smokers. Laboratory studies were also carried out. I don't know whether a
unique damage mechanism was ever established, but certainly correlations were
established between smoking and blood pressure and (I think) between smoking
and vascular deterioration. Other causal relations were also found: the size
distribution of smoke aerosols produced in cigarette smoking is such as to be
optimal for trapping these particles in the lungs. Larger particles are
removed by the natural filtration system of the body; smaller particles pass
relatively harmlessly through the system; but the particles from cigarette
smoke are trapped in the alveoli. One of the more interesting mechanisms
hypothesized (quite a few years ago) for damage of lung tissue was the uptake
by the smoker of a small amount of a radioactive isotope of polonium. It is
found in all large leaf plants, but it doesn't usually cause harm if one
merely eats the plant. it quickly passes through the digestive system. If
one smokes the leaves, the smoke aerosols concentrate the polonium in the lung
tissue - at least this was thought to be true several years ago. Does anyone
know whether this mechanism is still in the vogue or has it been disproved?
I'm curious. Thanks.
--
----
Bill P. Curry, Ph.D. |Physics is fun.
EMSciTek Consulting Co. |Trying to make a living!
22W101 McCarron Road, |Phone: (630) 858-9377
Glen Ellyn, IL 60137 |Fax: same, but require prior notice
Home page: http://www.EMSciTek.com
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Archive provided courtesy of WaveGuide, http://www.wave-guide.org
Reprinted with permission of Roy Beavers, http://www.feb.se/EMF-L/EMF-L.html