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RE: Radiation Hormesis -- or not



If it were a genetic mutation, the odds favor (immensely) a negative effect.  This would translate to lower germination ratios (live plants per seed planted) and a mixture of positive and negative effects.  This is not what is observed.  



Dave Neil



-----Original Message-----

From: John Jacobus [mailto:crispy_bird@yahoo.com]

Sent: Friday, January 23, 2004 7:09 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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