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:[EMAIL PROTECTED] 
        Sent: Friday, 5 December 2008 2:11 PM
        To: Tony Henwood; [EMAIL PROTECTED]; 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 
        发送时间: 2008-12-05  06:00:03 
        收件人: [EMAIL PROTECTED]; Jan Shivers; histonet 
        抄送: 
        主题: 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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 
        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 <[EMAIL PROTECTED]>
        Date: Thu, 04 Dec 2008 09:35:09 
        To: Jan Shivers<[EMAIL PROTECTED]>;
        histonet<histonet@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: [EMAIL PROTECTED]
        [mailto:[EMAIL PROTECTED] 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
        [EMAIL PROTECTED]
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