AW: [ RadSafe ] query

[John Jacobus]

Howard,
Sorry you disagree, but I was not asking for your
concurrence. 

--- howard long <hflong at pacbell.net> wrote:

> Hot air, John!
> BEIR, with admittedly easy-on-the-bureacracy LNT,
> does NOT "try to fit all the data points"
> LNT selectively excludes (or mingles or uses 1 tail
> test) with low dose data in
> 1, Breast Ca in Bomb survivors (under 10 rad)
> 2, " in Canadian fluoroscopy
> 3 Lung ca - Iowa controls and cases in 1% outlier
> generalizerd
> 4   "  USA Co mortality less with more Radon (except
> 1% Iowa outlier)
> 5, NSWS 
> etc, etc
>  
> Howard Long
> 
> John Jacobus <crispy_bird at yahoo.com> wrote:
> Rainer,
> Thank you for your comments. Like Mike, I do not
> subscribe to the LNT, but what I believe is not
> really
> that important to the discussion. 
> 
> I have considered the LNT to be the simplest model
> that mathematically fits the data points. 
> Unfortunately, it tries to fit all the data, both
> epidemiological, animal, and cellular data. I
> believe
> that cellular data is useful as it study what
> radiation effects are occuring and how the cells
> respond to the effects that occur. 
> 
> However, organisms are made up of many highly
> differeniated cells that evolved to defend the whole
> organism. When individual cells are damage, by
> radiation, chemicals or age, they release compounds
> that signal distress. Cells may die, be repaired by
> cellular response, or killed by other cells. Thus,
> cells in isolation do not represent the whole
> organism. (I assume that you know most of this
> already.)
> 
> In separate studies, animal and human populations
> are
> studied. Unfortuately, may such studies are based on
> acute doses and high dose rates. To me it is
> obvioius
> that radiation effects occur at both high and low
> doses, and high and low dose rates. However, at low
> doses and dose rates, which may workers are exposed
> to, biological systems (cellular and the whole
> integrated system of tissue) repair damaged cells or
> kill those that are defective. That is why there are
> no observed radiation effects below 100 mSv.
> 
> Again, when you combine all of this data, cellular
> and
> epidemiological, and try to fit it to a simple dose
> response curve, you get a linear plot. It may not
> reflect what is really going on, but it is the
> simplest relationship that can be made. This is what
> the BEIR committee was tasked to do.
> 
> My understanding for studing the ATB survivors is
> that
> they represent a large population whose exposures
> are
> well known. Also, the low dose group provide a
> control to the higher dose groups. This eliminates
> the problem of comparing the highly exposed
> population
> to some other group, like the rest of the Japanese
> population who may not have non-radiation bomb
> effects. 
> 
> --- Rainer.Facius at dlr.de wrote:
> 
> > Mike:
> > 
> > Despite my serious disagreement with BEIR VII-2's
> > endorsement of the LNT postulate as a scientific
> > fact, I concur that conspiracy theories like
> biased
> > committee selection are unreasonable or worse. 
> > 
> > The rows stirred by several anti-nuclear activist
> > organisations and which accompanied the assembly
> of
> > the committee testify that many members to be were
> > villainised as minions of the nuclear
> establishment
> > since they were accused of NOT subscribing to LNT.
> > In fact, several of the epidemiologists which are
> > (rightly) renowned for their empirical work on
> human
> > carcinogenesis from occupational radiation
> exposure
> > could be quoted as stating that their data on
> > radiation workers are compatible with anything
> from
> > hormesis to LNT. 
> > 
> > They also often emphasised the relevancy if not
> the
> > pre-eminence - as far as radiation protection
> > standards are concerned - of findings from studies
> > on truly chronically exposed worker populations
> > above findings from high dose rate studies such as
> > therapeutic or ATB exposures. Yet, from the
> > beginning of their professional career these
> > epidemiologists appear to have been conditioned to
> > somehow regard the ATB survivor findings as the
> > 'gold-standard' of radiation epidemiology. The
> fact
> > that in the 1970s and 1980s only data from the ATB
> > survivor studies could boast error bars which at
> > least above 200 mSv excluded the y-axis may have
> > biased them to rest content if their own data
> > admitted a LNT line which within the confidence
> > limits did not contradict the ATB LNT line. 
> > 
> > Then, and even more so in the 90s, their data (at
> > least from that handful of really large studies
> > which I happen to know) would have been equally
> well
> > - and from the parsimony principle even better -
> > represented by a 'no-effect' model, up to say 500
> > mSv. Still, and without an attempt to justify this
> > self-restraint, the only answer sought from their
> > data was again whether they would be compatible
> with
> > the then current ATB LNT line. The rationale
> > occasionally given that the ATB data yielded more
> > definite (alias accurate) risk estimates was at
> > least as weak as the DDREF uncertainty was large,
> > not to speak of the other imponderabilities of
> > extrapolating from the ATB survivors to non
> Japanese
> > worker populations. 
> > 
> > Why despite of their own professional expertise
> they
> > subscribed to the LNT postulate can only be
> guessed.
> > One reason may be - in line with still much of
> > contemporary biology - the - with hindsight
> peculiar
> > - preoccupation with initial DNA damage as the
> sole
> > determinant of an organism's response to genotoxic
> > substances, among which radiation is just one. In
> > conjunction with their report also the protocols
> of
> > BEIR VII-2's proceedings back the assumption that
> > this outdated notion might have been influential.
> > 
> > Another, and as I speculate, probably decisive
> > reason might have been the import of the
> disastrous
> > Brenner et. al. paper published in PNAS
> > 100#24(2003)13761-66. Authored by an excerpt from
> > "Who is Who in radiation biology" it still appears
> > mysterious how that manuscript could make it into
> > the pages of PNAS. Classified by another luminary
> in
> > radiation research (actually a doyen) as "a
> horrible
> > paper" and "shoddy work" at least in one detail it
> > is outright fraudulent, i.e., in asserting that in
> > Cardis et al. 1995 a significant increase in
> > leukaemia mortality had been demonstrated. Other
> > aspects such as the design of their figure 2 have
> > again by some most knowledgeable experts been
> > classified as "misleading" where I once more would
> > prefer fraudulent. 
> > 
> > (As an aside: another really strange aspect with
> > this paper - as with all PNAS publications - is
> that
> > once it has been printed it effectively is
> immunized
> > against public professional criticism. In contrast
> > to all other scientific journals I know, the NAS
> > offers no manuscript category "Letters to the
> > Editor" or "Correspondence" or "Matters Arising"
> > where controversial aspects of a paper could be
> > publicized. At least at that time I was unable to
> > find a section where I could submit the commentary
> > which I had prepared already.)
> > 
> > So, at least as far the compliance of the
> > 'epidemiology members' of the committee is
> > concerned, my guess is that a mixture of (self-)
> > conditioning, of DNA-'obsession', and the imposing
> > author list of the PNAS paper was instrumental in
> > winning their consent to a conclusion which
> > continues the tradition of leaning on a perceived
> > overriding predominance of the ATB survivor data.
> > 
> > Fortunately, another at least as distinguished
> > scientific body, the French Academy of Sciences
> 
=== message truncated ===


+++++++++++++++++++
"Every now and then a man's mind is stretched by a new idea and never shrinks back to its original proportion." -- Oliver Wendell Holmes, Jr.

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

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