No Subject

[james.g.barnes@att.net]

Good Afternoon, all;

I find the recent articles on cytoplasmic alpha exposure 
very interesting,

One of the paradigms that I have always used was an 
experiment that I read about ten years ago.  It may be 
familiar to some of you; if so please post the citation 
to the board.  I will summarize.  (By the way, I'm trying 
to type this with a 1" thick post-surgery bandage on my 
right index finger, so my typing is a bit below par right 
now.  Please excuse any typos.)

The researcher took a number of wasp eggs.  In wasp eggs, 
the nucleus is not centered in the cell; it is very close  
to the end of the oval shaped cell.

The researcher placed the eggs with all nuclei facing 
"up".  He then irradiated with alpha particles.  The 
alpha range ensured that the nuclei were exposed.

He then took another batch and placed the nuclei "down".  
He re-irradiated.  In this case, the alpha range in 
tissue meant the cytoplasm was exposed, but the nucleus 
was not.

He found that the cellular effects of the "nucleus up" 
group was many times (X 100, if I recall) greater than 
the "nucleus down" group.  Concluded that the nucleus was 
the most highly radiosensitive location in the cell.

I don't think the fact that cytoplasmic exposure causing 
nuclear damage is the key.  I think the key is more along 
the lines of the dose differential (the "Q" if you will), 
between nuclear exposure and cytoplasmic exposure.

Jim Barnes, CHP
Radiation Safety Officer
Rocketdyne/Boeing
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html