RE: paraffin-embedding and staining help

From:"Smith, Allen"

As solvents for paraffin or pine resins (mounting media) xylene and toluene
are interchangeable (and miscible).  Most of us prefer xylene for embedding
because its higher flash point makes it safer to work with. (Xylene's high
flash point is not due to its slightly higher molecular weight but due to
the fact that it is a mixture of 4 isomers.  Mixtures tend to remain liquids
at both higher and lower temperatures than pure substances - like toluene -
do.) Xylene does take longer than toluene to evaporate from the specimen in
molten paraffin, but that is not a problem in a vacuum oven.  If you don't
have a vacuum oven, you should let the tissue sit in molten paraffin
overnight to allow complete evaporation of the xylene.  Some of us prefer
toluene as a solvent for mounting media because it evaporates faster.
Personally, I prefer xylene for both applications.

Allen A. Smith, Ph.D.
Barry University
School of Graduate Medical Sciences
    Podiatric Medicine and Surgery
Miami Shores, Florida  33161-6695 

-----Original Message-----
From: []
Sent: Tuesday, January 14, 2003 11:30 AM
To: ''
Subject: paraffin-embedding and staining help

I have two questions:

1. when paraffin-embedding tissue, can you use xylene instead of toluene?

2. I am doing staining for cx43 (texasRed) in mice cardiomyocytes and
at distribution under confocal microscopy.  Does anyone know of a cell
marker that would allow me to locate cx43 in reference to cell surface, to

I would really appreciate any help you can give.
Thanks in advance,
Patience Sutton (M.Sc. candidate)
Department of Physiology and Pharmacology
University of Western Ontario

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