Re: Does Size Matter? please send review

["Monty Charles" <charlemw@novell1.bham.ac.uk>]

I would very much like to read the review you mention.  Thank you for 
pointing it out.

Best regards

Monty Charles
*************************

> Date:          Thu, 29 Oct 1998 21:13:51 -0600 (CST)
> Reply-to:      radsafe@romulus.ehs.uiuc.edu
> From:          Muckerheide <muckerheide@mediaone.net>
> To:            Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
> Subject:       Re: Does Size Matter?

> Hi Martin, group,
> 
> The following statement reflects a misperception related to the
> effects of radiation:
> <snip>
> >      I don't think that it matters whether one is discussing external gamma
> >      exposure or ingested exposure when considering this, as in both cases
> >      the number of DNA breaks will be more-or-less proportional to body
> >      mass for a given dose.
> <snip> 
> The number of DNA breaks is not relevant. Molecular biology that
> has been developing since the 1980s has shown that DNA breaks are
> more than a 1 million times greater from normal metabolism
> (~10^6/cell/day, with 30,000 at any given time, with a repair
> half-time of 5 to 45 minutes) vs. background radiation
> (~10^-5/cell/day). 
> 
> Dozens of normal events (eg, a cup of coffee, exersize, vitamins,
> anti-oxidants, etc) overwhelms the oxidative effects of multiples
> of background radiation on DNA damage. Although the fraction of
> double-strand breaks is greater (2x10^-2 vs 2x10^-5), it is still
> insignificant compared to normal metabolism. 
> 
> A damaged cell will go through 3 to 6 phases of carcinogenesis,
> with up to a billion transformations, before being promoted to a
> cancer cell. The known mechanisms of radiation carcinogenesis are
> not related to DNA damage, but instead to effects on immune system
> and cellular communications functions that control the cellular
> and DNA damage prevention, repair, removal processes. 
> 
> A synthesis of these results that has been the subject of a review
> by leading national experts in the molecular biology of the cell
> is being prepared for publication. A June 98 presentation on the
> data and analysis with refs can be provided.
> 
> Thanks.
> 
> Regards, Jim Muckerheide
> Radiation, Science, and Health
> ==============================
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> 
Dr Monty Charles
Reader in Radiation Physics
School of Physics & Astronomy
University of Birmingham
Edgbaston
Birmingham B15 2TT
United Kingdom
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