[Histonet] IHC on paraformaldehyde-fixed

Fri Dec 5 10:08:46 CST 2008

I have been curious about this discussion. we used 4% paraformaldehyde
for smaller biopsies only because it has a faster penetration to tissue
than 10% formalin. In all my IHC that I have done. I observe that doing
an IHC with 4% paraformaldehyde does not necessarily need  antigen
retrieval  in comparison to 10% formalin either it will be human or
animal tissue but this depends on how long was it fix, our 4%
paraformaldehyde we fix smaller biopsies like nerve,muscle, skin for 6
to 12 hrs. and for formalin it is 12 to 48 hours or more. Maybe you can
comment on the effect on this to tissue if you say you will use 4%
paraformaldehyde for storage and transportation. 

Reuel Cornelia, BS MT, AMT
Cellular Pathology
Texas Scottish Rite Hospital for Children
2222 Welborn Street
Dallas, TX 75219
Tel: 214-559-7766
fax: 214-559-7768

>>> "Tony Henwood" <AnthonyH <@t> chw.edu.au> 12/04/08 9:29 PM >>>
tf wrote:

"I DO believe that one reason some people use 4% PFA rather 10%
formalin is that PFA is a bit more stable, both for storage and
transportation~~~."

I have not heard this before.
Do you have a reference for this?

Regards 

Tony Henwood JP, MSc, BAppSc, GradDipSysAnalys, CT(ASC) 
Laboratory Manager & Senior Scientist 
Tel: 612 9845 3306 
Fax: 612 9845 3318 
the children's hospital at westmead
Cnr Hawkesbury Road and Hainsworth Street, Westmead
Locked Bag 4001, Westmead NSW 2145, AUSTRALIA 

	-----Original Message-----
	From: tf [mailto:tifei <@t> foxmail.com] 
	Sent: Friday, 5 December 2008 2:11 PM
	To: Tony Henwood; anh2006 <@t> med.cornell.edu; Jan Shivers;
histonet
	Subject: Re: RE: [Histonet] IHC on paraformaldehyde-fixed

	the basic principles are the same for most cross-linking
fixatives and induce similar bonds 
	the difference you observed between may due to any other
variability, or the co-fixative you used.

	I DO believe that one reason some people use 4% PFA rather 10%
formalin is that PFA is a bit more stable, both for storage and
transportation~~~.

	2008-12-05 

________________________________

	tf 

________________________________

	发件人： Tony Henwood 
	发送间： 2008-12-05  06:00:03 
	收件人： anh2006 <@t> med.cornell.edu; Jan Shivers; histonet 
	抄送： 
	主： RE: [Histonet] IHC on paraformaldehyde-fixed 

	Interesting point.
	Since 10% buffered formalin (made from the concentrated 38%
	formaldehyde) contain about 1% methanol, has it been shown that
this has
	a deleterious effect on ANY antigens or are we expecting this
worse case
	senario as being the norm?
	I am not aware of any antigens (or antigen-antibody combination)
that
	has been badly effected by 10% formalin that is NOT effected by
10%
	formaldehyde. Are you aware of any??
	Regards
	Tony Henwood JP, MSc, BAppSc, GradDipSysAnalys, CT(ASC)
	Laboratory Manager & Senior Scientist
	Tel: 612 9845 3306
	Fax: 612 9845 3318
	the children's hospital at westmead 
	Cnr Hawkesbury Road and Hainsworth Street, Westmead 
	Locked Bag 4001, Westmead NSW 2145, AUSTRALIA 
	-----Original Message-----
	From: anh2006 <@t> med.cornell.edu [mailto:anh2006 <@t> med.cornell.edu] 
	Sent: Friday, 5 December 2008 1:31 AM
	To: Tony Henwood; Jan Shivers; histonet
	Subject: Re: [Histonet] IHC on paraformaldehyde-fixed
	So true. However, be aware that 10% neutral buffered formalin we
use has
	methanol in it which may affect certain antigens so there may be
some
	difference in staining (hence why for mouse work we now only use
4% PFA
	in pure PBS). It is good to be aware of the other ingredients in
your
	fixative solutions, whether commercially prepared or a homemaede
recipe,
	as it isn't only the formaldehyde fixative which can make a
difference.
	-----Original Message-----
	From: Tony Henwood <AnthonyH <@t> chw.edu.au>
	Date: Thu, 04 Dec 2008 09:35:09 
	To: Jan Shivers<shive003 <@t> umn.edu>;
	histonet<histonet <@t> lists.utsouthwestern.edu>
	Subject: RE: [Histonet] IHC on paraformaldehyde-fixed
	Gee I hate the term paraformaldehyde (as many of you probably
know)
	This is an example of how confusion of terms can cause
unnecessary work.
	Is "4% paraformaldehyde" different from 4 % formaldehyde?
	No
	Should any procedure done to tissues fixed in "4%
paraformaldehyde" give
	results different to those fixed in 4% formaldehyde or 10%
formalin? 
	No since they are the same thing.
	As Manoonkitiwongsa and Schultz (Histochem J 34: 365-367, 2002)
state
	when paraformaldehyde actually becomes a fixative, it is no
longer
	paraformaldehyde by chemistry or fixation capacity. Rather, it
is
	formaldehyde in water without methanol or any other stabiliser.
Without
	heat and an alkaline environment, paraformaldehyde in water is
simply a
	paraformaldehyde suspension with little fixation capacity. If
the
	fixative is prepared from paraformaldehyde then it should be
termed 4%
	formaldehyde freshly prepared from paraformaldehyde. If a
concentrated
	formalin solution (40% formaldehyde) is used, then it should be
termed
	10% formalin.
	If you do a search on Histonet for paraformaldehye, you will
find that
	this topic has been extensively discussed.
	Regards
	Tony Henwood JP, MSc, BAppSc, GradDipSysAnalys, CT(ASC)
Laboratory
	Manager & Senior Scientist
	Tel: 612 9845 3306
	Fax: 612 9845 3318
	the children's hospital at westmead 
	Cnr Hawkesbury Road and Hainsworth Street, Westmead 
	Locked Bag 4001, Westmead NSW 2145, AUSTRALIA 
	-----Original Message-----
	From: histonet-bounces <@t> lists.utsouthwestern.edu 
	[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of
Jan
	Shivers
	Sent: Thursday, 4 December 2008 8:34 AM
	To: histonet
	Subject: [Histonet] IHC on paraformaldehyde-fixed
	Has anyone ever done IHC on parafomaldehyde-fixed tissues, and
if so,
	how well did it work?  Will the same antigen-retrieval methods
used with
	formalin-fixed tissue be applicable?
	I'm asking for an investigator, who already has his tissues
fixed in
	paraformaldehyde.
	Jan Shivers
	Senior Scientist
	Pathology Teaching Program
	Histology/IHC/EM Section Head
	University of Minnesota
	Veterinary Diagnostic Laboratory
	1333 Gortner Ave.
	St. Paul, MN  55108
	612-624-7297
	shive003 <@t> umn.edu_______________________________________________

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