[ RadSafe ] Two interesting papers on DNA repair mechanisms

[Dan W McCarn]

Dear Howard, Clayton & Barbara:

Given that cancer is so very tough to understand and treat, I imagine that
there are thousands of molecular geneticists and biologics trying to wrap
their brains around these issues.

At least in the Glioma stem cell, the damage causing the cancer seems to be
fairly specific in that the gene responsible for production of the CD133
lipoprotein, turning-on the DNA damage response, is frequently selectively
activated in Glioma which protects it's genome, but not in the adjoining
brain cells. So what is it about a well-behaved brain cell that causes it to
suddenly "change" to such an aggressive cancer with radtiation-resistant
properties? Why is it vible given all of the other possible 


Dan ii

--
Dan W McCarn, Geologist
108 Sherwood Blvd
Los Alamos, NM 87544-3425
+1-505-672-2014 (Home - New Mexico)
+1-505-670-8123 (Mobile - New Mexico)
HotGreenChile at gmail.com (Private email) HotGreenChile at gmail dot com


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Howard Long
Sent: Friday, July 02, 2010 18:42
To: Clayton J Bradt
Cc: radsafe at health.phys.iit.edu
Subject: Re: [ RadSafe ] Two interesting papers on DNA repair mechanisms

To further complicate it, what quantity of DNA breaks and the (Pollycove)
reported 10 orders of magnitude greater repair occur with the various types
of cancers?

The numbers are beyond my comprehension, so as with the many factors in an
individual patient's healing, I am guided by apparent end results, as much
art as science and not manageable with limited information like codes.

Howard Long 

On Jul 2, 2010, at 12:31 PM, Clayton J Bradt <CJB01 at health.state.ny.us>
wrote:

> 
> Barbara,
>  
> I still have the same job essentially, I've just been moved to where 
> they think I will cause less trouble.
> 
> Not being a biologist I have difficulty even formulating the questions 
> I have about the whole cancer-radiation process.  Let me try again:
> 
> Every somatic cell regardless of tissue type has identical DNA - all 
> the same genes.  Cancers are all characterized by the loss of 
> differentiation and uncontrolled proliferation of cells.  What causes 
> a cell to go bad, so to speak?  It is presumed to be the result of some
change or changes in the
> cell's genetic make-up.   Since all cell's start off with the same DNA it
> is reasonable to assume that the same specific change(s) must occur in 
> any cell before it undifferentiates and begins proliferating
uncontrollably.
> The HPV/cervical cancer example supports this.  The mutations are not 
> random but consist of very specific genetic sequences that are spliced 
> into the somatic cell's DNA.  Would different genes spliced into the 
> DNA have the same effect? That seems unlikely.
> 
> Does each type of cancer result from specific sets of genes being 
> either spliced into or deleted from cell DNA? The similarity of all 
> cancers (loss of differentiation and uncontrolled proliferation) 
> suggests that very similar if not identical genes are involved. But if 
> so, how does random DNA damage, such as results from ionizing 
> radiation (and presumably from chemical agents), result in specific
genetic mutations?
> 
> 
> Clayton J. Bradt
> Principal Radiophysicist
> Laboratory for Inorganic & Nuclear Chemistry NYS Dept. of Health
> 518-474-1993
> 
> blreider at aol.com wrote on 07/02/2010 02:28:08 PM:
> 
>> blreider at aol.com
>> 07/02/2010 02:28 PM
>> 
>> To
>> 
>> CJB01 at health.state.ny.us, radsafe at health.phys.iit.edu
>> 
>> cc
>> 
>> Subject
>> 
>> Re: [ RadSafe ] Two interesting papers on DNA repair mechanisms
>> 
>> Clayton,
>> 
>> Hope you are well.  I see from your signature that you either have 
>> changed jobs or you have new stationary yet again.
>> 
>> I don't understand why the two statements are a contradiction.
>> Cancer is a general name for numerous diseases with numerous causes.
>> Not all non-radiation initiated cancers have to also be initiated by 
>> radiation.  Are you saying that all radiation initiated cancers also 
>> don't have another cause?  I guess that could be true if there are no 
>> non-radiation causes for random DNA strand breaks.*
>> 
>> I don't know enough about the different cervical cancers to add 
>> anything about the molecular structure, however for other cancers 
>> there can be many different initial cell types all lumped together 
>> under the name of the organ involved.  Is all cervical cancer 
>> initiated in the same type of cell?  Lung cancer has numerous initial 
>> lung cell types, and some of the same types of lung cancers that are 
>> attributed to smoking are also attributed to radiation 
>> (Adenocarcenoma).  Smoking also is linked to other types of lung 
>> cancers that are not thought to be radiation induced (small cell).
>> 
>> The research to find mechanisms for cancer production is interesting 
>> as applied to the statistics used in our field, hence previous 
>> comments about LET and QF.
>> 
>> Regards
>> 
>> Barbara Reider, CHP
>> 
>> *And to make this more difficult, perhaps indirect radiation induced 
>> strand breaks are not all random.  I though the early cell data 
>> showed random breaks though (anyone with newer info?).
>> 
> IMPORTANT NOTICE: This e-mail and any attachments may contain confidential
or sensitive information which is, or may be, legally privileged or
otherwise protected by law from further disclosure. It is intended only for
the addressee. If you received this in error or from someone who was not
authorized to send it to you, please do not distribute, copy or use it or
any attachments. Please notify the sender immediately by reply e-mail and
delete this from your system. Thank you for your cooperation. 
> 
> _______________________________________________
> You are currently subscribed to the RadSafe mailing list
> 
> Before posting a message to RadSafe be sure to have read and 
> understood the RadSafe rules. These can be found at: 
> http://health.phys.iit.edu/radsaferules.html
> 
> For information on how to subscribe or unsubscribe and other settings 
> visit: http://health.phys.iit.edu
_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood the
RadSafe rules. These can be found at:
http://health.phys.iit.edu/radsaferules.html

For information on how to subscribe or unsubscribe and other settings visit:
http://health.phys.iit.edu