[Histonet] Davidson's fixative and IHC question

[Anatoli Gleiberman]

My experience with small tissue samples (such as half of mouse brain or slice of mouse liver) fixed in Davidson or other alcoholic formalin fixatives is to fix it no more than overnight and transfer into 70% ethanol (almost forever). The majority of antigens will be preserved much better than in regular NBF.

Anatoli Gleiberman, PhD
Director of Histopathology
Buffalo Biolabs LLC,
73 High Street
Buffalo, NY, 14203

Phone:716-849-6810x354
e-mail:agleiberman at buffalobiolab.com



-----Original Message-----
From: Jay Lundgren via Histonet [mailto:histonet at lists.utsouthwestern.edu] 
Sent: Monday, February 22, 2016 2:53 PM
To: Judi Ford
Cc: histonet at lists.utsouthwestern.edu
Subject: Re: [Histonet] Davidson's fixative and IHC question

Today I learned what Davidson's fixative is!  Thanks!

Anyway, so it's a strong alcoholic formalin.  The answer to your question is; yes.  You need to be careful of overfixation, thus masking the epitope in question.

From Dako:

     " Of the many pre-analytical variables which affect IHC and ISH results, fixation is probably the most significant, impacting many other variables such as antigen retrieval and epitope binding. Unfortunately, to date, no single fixative has proven to be ideal for all targets and detection methods. However, it is generally more deleterious for tissue to be ‘underfixed’, rather than ‘overfixed’."

Make sure not to leave your specimen in Davidson's for more than 24 hrs, and then in formalin for *less* than 72 hrs and you should be OK.  If staining is unsatisfactory you might have to tinker with your antigen retrieval protocol (longer) or primary Ab incubation time (longer).

  Sincerely,

        Jay A. Lundgren, M.S., HTL (ASCP)

On Mon, Feb 22, 2016 at 11:45 AM, Judi Ford via Histonet < histonet at lists.utsouthwestern.edu> wrote:

> Hi Everyone. Hope you all had a really good weekend. Thanks for the 
> replies to my double ihc question.
>
> I do have another question; this one is from a friend of mine. Her 
> client wants to do ihc on rabbit eye tissue. The tissue will be fixed 
> in Davidson's fixative for 24 hours then in 10% NBF. Will this have 
> affect future ihc projects?
>
> Thanks,
> Judi
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