Dolores,

If the tissue is not embedded, but straight out of the fixative, wash the 
chopped up sample  for a couple of hours in several changes of sterile water 
and then proceed as usual to the digestion step (spin down before each 
change to remove as much of the water as possible).
Extraction of DNA  for PCR from long stored formalin fixed, paraffin wax 
embedded tissues can be a problem, as the DNA becomes degraded over time,  
(I tried to get PCRable DNA from blocks embedded  in 1942, with no joy) and 
standard phenol/coloform extraction (ref Maniatis) might be better and give 
larger yield than the Quigen kit.

Hope this helps
Louise Renton


>From: Dolors Fuster 
>To: histonet@pathology.swmed.edu
>Subject: DNA
>Date: Mon, 22 Jul 2002 20:26:41 +0100
>
>Hi histonetters !
>
>What do you recommend us to obtain the best results in DNA extraction
>from formalin fixed tissue? should we do any kind of treatment before 
>starting the
>extraction? (Water rinses, alcohol changes....)
>
>We are usin Qiagen kit with good results for parafin embeded samples
>fresh tissue and other kind of samples (cell culture, serum...). but
>are not successful with formalin fixed tissue
>
>Thanks in advance
>Dolors Fuster
>
>Tecnic Especialista en
>Anatomia Patologica
>Departament d'Anatomia i Embriologia Humana
>Facultat de Medicina (HCP)
>Universitat de Barcelona
>ICQ 14146798
>
>http://www.fashionmas.com/click/




Louise Renton
Bone Research Unit
MRC
Johannesburg
South Africa
Tel & fax +27 11 717 2298
"Time flies like an arrow, friut flies like a banana"
ex

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