Extracting DNA from frozen plasma

R M Bernstein ralph at ccit.arizona.edu
Sat Sep 9 12:54:54 EST 1995

In Article <42s32o$eua at newsbf02.news.aol.com>, drrutledge at aol.com
(Drrutledge) wrote:

>Are there any special precautions about that need to be taken when thawing
>out a blood sample (plasma) and then extracting DNA? 

is it spun down?  plasma is essentially "dilute" cells, so if its not spun
down i would spin it down and then put it in hot (65 degrees) lysis buffer. 
i wouldnt think that i could get dna , or at least concentrated dna from
unspun plasma.  if it has wb cells in it, you can probably still spin it down.

> Since the sample was
>frozen, I suspect that all the cells will be broken (from being frozen and
>thawed) and I thought that this could affect the high molecular weight DNA
>(due to DNAses..?) which could be a problem during a PCR reaction. Help.

no prob for pcr, unless you are doing long-pcr.  i usually shear my genomic
dna in a syringe w/a 18 gauge needle before pcr'ing it.  i would try an
unimportant  test frozen plasma sample first to see if the lysis method, (in
current protocols) works.  OR, you could always also use one of the
commercial methods.

regards, ralph
Ralph M. Bernstein
Dept of Micro/Immuno
University of Arizona
Ph: 602 626 2585
Fx: 602 626 2100
url: http://lamprey.medmicro.arizona.edu

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