[ RadSafe ] Re: Radiation Hormesis

[John Jacobus]

If one does not believe there are problems with using small animal models (mice and rats) for chemical testing of effects in humans, should consider that approximately 80% of the drug responses seen in such animals do not lead to effective results in humans.
   
  But the issue is not effects in one species over another.  It has to do with safety in humans.  Only about 15% of a regulator ruling is based on the science.  The rest is the politics.

Steven Dapra <sjd at swcp.com> wrote:
  Dec. 27

Yes, don't we all love those eminent scientists. Okay, enough on 
that front.

". . . proof that a substance, which had been recognized as 
carcinogenic in animals, actually causes cancer in man would require in 
most cases extemely complex and lengthy epidemiologic studies. In many 
cases, it may be impossible to obtain such proof because of the complexity 
of controls that would be needed for a satisfactory 
demonstration. Therefore, the only prudent course of action at the present 
state of our knowlege is to assume that chemicals which are carcinogenic in 
animals could also be so in man, although the direct demonstration in man 
is lacking."

The citation is: Umberto Saffiotti, "The Laboratory Approach to 
the Identification of Environmental Carcinogens," in Proceedings of the 
Ninth Canadian Cancer Research Conference 1971, edited by P. G. Scholefield 
(University of Toronto Press, 1972), pp. 23-26; cited in Federal Register 
42:192 (October 4, 1977): 54152. I am quoting from "The Apocalyptics 
Cancer and the Big Lie," by Edith Efron (Simon and Schuster, 1984). Efron 
quotes Saffiotti on p. 87.

Sure, I'll grant you that was 1971 --- 36 years ago and a lot has 
changed since then. Or has it? Are we any closer to knowing *for certain* 
whether nor not it is possible to extrapolate from carcinogenicity in 
animals to carcinogenicity in humans?

To further complicate matters, according to Efron, cats, dogs, 
rats, mice, and hamsters get cancer from 2-acetylaminofluorene; but guinea 
pigs, lemmings, and the cotton rat do not. And it goes on and on. See pp. 
198-190 of Efron for more examples of selective carcinogenicity. She gives 
citations for everything, citing to the scientific literature, or to 
government reports on carcinogenicity.

Steven Dapra


At 09:18 PM 12/27/07 -0500, BLHamrick at aol.com wrote:
>
>And, I'm sure it comes as no surprise that anti-everythings also argue just
>the opposite (of what Floyd noted below) about animal studies when it suits
>them.
>
>Just a couple of weeks ago (December 18, 2007), there was a very sensible
>editorial in the LA Times about the ongoing uproar regarding phthalates in
>plastics ("Stop Scaring Us"). The author was roundly attacked in 
>three letters
>(published December 23, 2007). (One from the eminent scientist Senator 
>Diane
>Feinstein - said with tongue firmly in cheek). And, of course, one of the
>criticisms was that the columnist had dared to suggest that because 
>phthalates
>cause cancer in rats, it doesn't necessarily mean it will cause it in humans.
>
>The letter to the editor stated, "[The columnist] repeats the old saw that
>rats have different metabolism than people. So he'd rather test people? 
>Animal
>testing to predict risks posed to humans by toxic substances is a
>well-established principle that provides the basis for the nation's 
>fundamental cancer
>policy and a host of laws seeking to protect us against this deadly disease.
>If a chemical can induce tumors in mice, we are not immune."
>
>The problem I have with the anti-everythings (aside from the cherry-picking)
>is they seem to be quite willing to make any argument, even to the point
>where they may make two completely inconsistent arguments depending on 
>the day
>of the week (or the audience), to support their agenda.
>
>Barbara L. Hamrick
>
>In a message dated 12/27/2007 11:10:49 AM Pacific Standard Time,
>Floyd.Flanigan at nmcco.com writes:
>
>I am a firm supporter of Hormesis but with all of the other
>environmental influences which can mask most true expressions of the
>Hormetic Effect, I fear it will be a very long time before we see such a
>study. I suppose it could be conducted on lab animals, but no matter
>what evidence was produced, the nay-sayers would find their way back to
>the fact that humans have a different physiology than the test subjects.
>



+++++++++++++++++++
"If history teaches any lesson it is that no nation has an inherent right to greatness.  Greatness has to be earned and continually re-earned."
- Norman Augustine, Chairman of the National Academies Committee 

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com
       
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