[Histonet] zinc formalin on ISH

[Liz Chlipala]

Jorge

Why would switching from formalin to zinc formalin shorten your
processing time?  Isn't the fixation time for formalin and zinc formalin
the same?  My impression is that any formalin based fixative is going to
take about 6 hours to adequately fix tissue, if it is shorter than that
you will get a combination of formalin and alcohol based fixation (via
your processing post fixation).  Back in the 80's when we first started
using zinc formalin as a replacment to B-5 you needed to fix in zinc
formalin for at least 6 hours to obtain the better nuclear detail.  The
zinc chloride or zinc sulfate that is used in the fixative acts similar
to the mercuric chloride in the B-5 fixative by precipitating nuclear
protein (both are considered a protein coagulants) therefore the better
morphology.  The zinc within the fixative also acts to preserve the 3
dimentionial structure of the protein molecule thus inhibiting excessive
cross linking of the formalin fixative (which may mask epitopes on the
protein molecule).  That's why it's a great fixative for both increased
nuclear detail and enhanced immunoreactivity.  But as far as I am aware
fixation time is no different than routine formalin fixation.  If
someone knows more, please correct me if I'm wrong. 

Liz   


Elizabeth A. Chlipala, BS, HTL(ASCP)QIHC
Manager
Premier Laboratory, LLC
P.O. Box 18592
Boulder, CO 80308
phone (303) 682-3949
fax (303) 682-9060
liz <@t> premierlab.com
www.premierlab.com
 
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-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Jorge
Dominguez
Sent: Thursday, July 03, 2008 11:09 AM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] zinc formalin on ISH

Hi,

I was wondering if anyone could offer some advise on zinc formalin. We
are currently using 10% NBF on our tissues. We are considering switching
to zinc formalin to shorten processing time. Any help would be greatly
appreciated.
Thanks
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