Re: EMF and DNA double-strand breaks

["Björn Cedervall" <bjorn_cedervall@hotmail.com>]

Radsafers with interest in the "EMF" issue:

I briefly read through the Bioelectromagnetics article today (below).
It is as I suspected - the single-cell assay (Comet). It is not
explained how the authors specifically assay for DSBs but they
referred back to Int. J. Radiat. Biol. (Lai & Singh, 1996, Vol. 69, 
pp.513-). So I looked at the latter article also. And again,
I find no clear explanation about how they quantify for DSBs.

Any comments would be valuable. The comet assay measures a fractional 
(%) change in DNA mass, not strand breaks (I am quite sure that I 
explained this to one of the authors by an email in 1996). To my
knowledge, there is no theory explaining the relationship between
% DNA mass change and ANY specific lesions (including SSBs or DSBs)
for the comet assay. I still find all this strange about the claimed
DSBs.

Bjorn
---------------------------------------------------
>Bioelectromagnetics
>Volume 18, Issue 2 (1997)
>Do electromagnetic fields interact directly with DNA?;

>Acute exposure to a 60 Hz magnetic field increases DNA strand breaks
>in rat brain cells; Henry Lai, Narendra P. Singh

bjorn_cedervall@hotmail.com
Depts. Medical Radiation Biology & Medical Radiation Physics,
Karolinska Institutet, Box 260,
S-171 76 Stockholm, Sweden
Fax: Int + 468 343525 (Med. Radiation Physics)
Website: http://www.geocities.com/WallStreet/Exchange/8256/
Any opinions expressed above are those of mine and may not necessarily 
coincide with those of others.


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