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RE: Radiation Hormesis
Karl (and others),
We had and interesting laboratory experiment in Radiation Biology when I
was in college where we irradiated bean seeds, fruit flies, and onion
root with low, med, and high doses from a Co-60 source from a local
hospital. To show the effects of hormesis, no effect, and ill effect
the students all received seeds from each exposed group plus seeds that
did not get any extra dose (controls). We planted the seeds in cups at
our home, gave all plants the same amount of water and noted the
differences. The seeds with the low doses had more vigorous growth,
smaller internodal lengths, and healthier leaves than the control. The
higher dose plants had brown shriveled leaves, stunted growth, and other
undesirable characteristics. We made a plot showing that as the dose
initially increased we saw a net positive effect (hormesis) but as the
dose continued to increase, a negative effect became apparent. This
made a lasting impression and I have believed in hormesis ever since. I
know people are not bean plants or fruit flies but this little
experiment gave the hormesis theory more believability than the LNT in
my mind.
As for the fruit flies I don't remember the low dose effects. What
stands out in my memory were the horrific mutations in the offspring of
the high dose flies.
The onion root tips were used so we could see the chromosome damage in
the cells undergoing meiosis.
See http://www.belleonline.com/n2v82.html RADIATION HORMESIS: ITS
HISTORICAL FOUNDATIONS AS A BIOLOGICAL HYPOTHESIS by Edward J. Calabrese
and Linda A. Baldwin for a good discussion on Hormesis.
Carl Speer
Real-Time Radiological Services, Inc.
2721 Losee Rd, Suite E
North Las Vegas, NV 89030
702.639.0066
www.RealtimeRad.com
RTRS@cox.net
-----Original Message-----
From: owner-radsafe@list.vanderbilt.edu
[mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of
RuthWeiner@AOL.COM
Sent: Monday, January 19, 2004 7:28 AM
To: "Karl Ellison"; radsafe-digest@list.vanderbilt.edu
Subject: Re: Radiation Hormesis
I have always wondered how one could distinguish hormesis effects from
ordinary good health. An example: small amounts of ionizing radiation
are supposed to stimulate bone knitting after a break (I read this
somewhere). However, the rates of bone recovery vary. Has there beenn a
controlled study of this phenomenon? After my latest hip surgery, my
doctor predicted that incorporation of the bone graft would take two
years. It took six months. I was taking a drug that enhances calcium
metabolism and I had quite a few xrays and I get a lot of exercise, so
was it the drug, the x-ray, the exercise, two of those, or all three?
Are there definitive studies showing hormesis?
I am perfectly ready to accept hormesis, but in the current radiophobic
climate, I believe we are better off just claiming no harm at less than
a particular dose. Hormesis is one of those phenomena that even if it
is real, doesn't SOUND real.
--
Ruth F. Weiner
ruthweiner@aol.com
505-856-5011
(o)505-284-8406
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