Re: DNA extraction for PCR
maybe the formalin residue in the fixed tissue (if not washed properly)
inactivates the enzyme used for digestion. Also check the concentration of
the sample.. too much DNA/protein from tissue might not spin down well in
the Qiagen, ie get stuck, and not give a good result.
>I don't know exactly why we are having quite good results with
>parafin sections and not the same with only fixed tissue....may be
>because in parafin sections formalin rests have disappeared after
>washing with water and diferent changes in alcohol?...I really don't
>know, it's sure that somebody better than me in this field
>can solve the doubt.
>From: "louise renton"
>To: TEC-LAB-DEP01@med.ub.es, email@example.com
>Subject: DNA extraction
>Date: Tue, 23 Jul 2002 07:33:03 +0000
>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
>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
> >From: Dolors Fuster
> >To: firstname.lastname@example.org
> >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
>Bone Research Unit
>Tel & fax +27 11 717 2298
>"Time flies like an arrow, friut flies like a banana"
>Join the world’s largest e-mail service with MSN Hotmail.
>Tècnic Especialista en
>Departament d'Anatomia i Embriologia Humana
>Facultat de Medicina (HCP)
>Universitat de Barcelona
Bone Research Unit
Tel & fax +27 11 717 2298
"Time flies like an arrow, friut flies like a banana"
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