Re: Alcohol based fixatives

From:Barry Rittman

I am not sure that it can be adequately defined.  Most I think assume that if the alcohol is a major component then the fixative can be regarded as alcohol based.
I am assuming that here we are talking about ethyl alcohol and methyl alcohol.
Alcohol penetrates faster than most other components in fixing solutions. However it is a poor fixative for some components. Below a certain alcohol concentration, some lipids will be retained.
My opinion is that if the concentrations of alcohol is less than around 70% it does not act effectively as a fixing agent. By the same token no matter what the concentration, it often  facilitates the penetration of many other components.
This may not be true in tissues containing large amounts of blood.
Barry wrote:

Dear Histonetters,
Just got home and skimmed the latest edition of the "Journal of Histotechnology" which is devoted to the subject of "fixation".  This edition will stand out as a bench guide (for now) to all of us dealing with the most dynamic discipline (ie. IHC) in histology.  As my lab does not use formalin (since 1995) as its routine fixative we have found ourselves, often alone, in developing  IHC protocols for new antibodies as they become available.  We use "Prefer" from Anatech (and they have been a good source of reference) when we have encountered our rare problems.
To throw a general question out there that is not specifically addressed in the discussion about fixatives; "Is there a definition of what constitutes a fixative as being alcohol based"?  For example; what percentage of alcohol constitutes "alcohol based" or or should a fixative description be based on the chemical which provides the primary mode of fixation.  With Prefer fixative the working solution is only 20% alcohol and is incorporated into the formulation as an agent to facilitate delivery of the primary fixative which is glyoxol.  The only antibody we are struggling with is TTF-1.
We all know this is a temperamental antibody (as noted in the literature).  If any glyoxol based fixative users out there have had success with TTF-1, any ideas or procedural notes would be much appreciated.
I'll stop for now until I've had an opportunity to give this wonderful edition of the J. of H. my full attention.  Thanks so much to the NSH, the contributors of the articles and the editorial staff for perhaps their finest combined effort.
Greg Luck
A.P. Supervisor
Deaconess Med Center
Spokane, WA (509)473-7393

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