Re: natural and un-natural radiation

["Bjorn Cedervall" <bcradsafers@hotmail.com>]

>But go even further:  The formation of reactive oxygen species by normal
>metabolism is millions of times greater than background radiation. (You 
> >are taking your anti-oxidants every day aren't you?  :-)

>Note that the normal "background" level of damaged DNA is about 30,000 >in 
>every cell, with a half-time of repair of 30-40 minutes).
Some sources say 100 000/day. I believe that the average half life is much 
shorter than 30-40 minutes. Many of these damages are lost bases which cause 
transient single strand breaks (SSBs). The SSBs are probably more or less 
harmless unless they occur close to one another on the opposite DNA strands 
(a probability which is very low). The SSBs cannot be compared to DSBs which 
are the most important (cell death, chromosomal aberrations, mutations) 
lesions caused by exposure to ionizing radiation (which also results in SSB 
formations).

>This has a high
>transient effect with thermal stress, e.g., exercise, drink a hot cup of
>coffee, etc.  Certainly the DNA break couldn't give a DAMN whether an 
> >OH-radical was caused by radiation at all!

Bjorn Cedervall   bcradsafers@hotmail.com


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