[Histonet] fixatives

[Steven E. Slap]

Hi HistoNetters

Dr. Ortega asked about the use of a fixative made up of of a 
combination of an alcohol and polyethylene glycol, and the possible 
advantages of using such a fixative in preserving RNA, DNA and 
proteins.  As it happens, this topic is examined at length in Chapter 
11 (Microwave stimulation of coagulant formalin-free fixatives) of 
the new edition of Kok & Boon's Microwaves for the Art of Microscopy.

Briefly, Dr. Boon has been promoting the use of non-crosslinking, 
formalin-free ethyl alcohol/PEG fixatives since the early 1980's. 
The first of these to become commercially available was Kryofix, a 
Merck product (which I believe is available from E M Sciences in a 
slightly different form today as NeoFix-  Rande Kline-  can you 
clarify this?).  Dick Dapson of Anatech and I developed a version 
when I was at Energy Beam Sciences which we called MicroFix.  Dr. 
Boon has her own version now, called BoonFix  Milestone has a 
version, called FineFix.  Sakura has its version (I don't know its 
trade name).

The theory is that the alcohol (ethyl alcohol or methyl alcohol) does 
the dehydration, while the PEG permeabilizes the cell membrane. 
BoonFix also contains acetic acid.  The fixative does not crosslink 
proteins, so no antigen retrieval is necessary for 
immunohistochemistry.  Preliminary testing seems to indicate that DNA 
and RNA preservation is far superior to formalin.

I would be happy to provide more information privately to those intersted.

best regards,
Steven Slap
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Steven E. Slap
Microwave Consultant
(413) 221-3678
microwaves <@t> comcast.net
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