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RE: Radiation Hormesis -- or not
John,
I know others on this list can answer better than I most of these
questions but I will give it a shot. I do think that your definition of
hormesis is too limiting. I believe that hormesis can be shown from
chronic or acute doses. A good example of hormesis from acute exposure
would be the demonstrated longevity of Japanese atomic bomb survivors.
The death rates from cancer of low dose survivors were less than that of
the control population. The A-bomb survivor study also refutes your
"When the agent is stopped, the hormetic effect is no longer evident
after a time" statement.
As for your question of "is it hormesis or genetic mutation?", I do not
know. But my definition of hormesis doesn't differentiate between the
two. A benefit is a benefit regardless of the mechanism that caused it.
Your question "Did you try and grow new plants from the seeds produced
from the mature, irradiated plants? From my lab report I see that all
of the bean plants died and did not produce other beans. This was
probably due to the 100 degree plus temps in July in central Texas. In
my report I concluded that the hormetic effect was heat tolerance due to
the number of low dose plants still standing after all the controls (and
high dose plants) had died. Please keep in mind this was not a research
project, just a lab exercise from a 13 week class in a two year
technical college. I have an AAS not a PhD
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: John Jacobus [mailto:crispy_bird@yahoo.com]
Sent: Friday, January 23, 2004 6:09 AM
To: Carl Speer; radsafe@list.vanderbilt.edu
Subject: RE: Radiation Hormesis -- or not
Carl,
A thought came to me. How do you know this was a
hormetic effect and not a genetic mutation? My
understanding is the a hometic effect involves the
addition of some simulus to an living organism to get
a beneficial response. You irradite mice to low doses
and you get a certain response, e.g., an increase in
the immune system. When the agent is stopped, the
hormetic effect is no longer evident after a time.
Maybe this definition for hormesis is too limiting,
but this is what I believe it is.
Seeds are not actively growing or responding
organisms. If you irradiated the growing plant, I
would agree that would be be a way of demonstrating a
hormetic effect. Did you try and grow new plants from
the seeds produced from the mature, irradiated plants?
I think that would have demonstrated the effect of
genetic mutation.
--- John Jacobus <crispy_bird@yahoo.com> wrote:
> Interesting. What were the doses?
>
> --- Carl Speer <rtrs@cox.net> wrote:
> > 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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> =====
> +++++++++++++++++++
> "I have sworn upon the altar of God, eternal
> hostility against every form of tyranny over the
> mind of man."
> Thomas Jefferson
>
> -- John
> John Jacobus, MS
> Certified Health Physicist
> e-mail: crispy_bird@yahoo.com
>
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=====
+++++++++++++++++++
"I have sworn upon the altar of God, eternal hostility against every
form of tyranny over the mind of man."
Thomas Jefferson
-- John
John Jacobus, MS
Certified Health Physicist
e-mail: crispy_bird@yahoo.com
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