Yes - but where is Russ?
Terry
-----Original Message-----
From: histonet-bounces@lists.utsouthwestern.edu
[mailto:histonet-bounces@lists.utsouthwestern.edu] On Behalf Of John
Kiernan
Sent: 01 October 2007 06:19
To: patsy ruegg; Histonet@lists.utsouthwestern.edu
Cc: Histonet@lists.utsouthwestern.edu
Subject: Re: RE: [Histonet] Polymer Paraffin
Dear Igor Deyneko,
Go for simple paraffin wax that melts between 55C and 60C. Additives,
especially unidentified polymers, probably have little value. Read on,
and check the Web and Library references.
The various paraffins and additives were discussed on Histonet several
(8-10) years ago, and the replies included comments from the major
authority in this field, Russ Allison of the University of Wales Dental
School in Cardiff. I hope this information is still available by way of
Histosearch.com, because Russ's original publications in the field are
not in many libraries outside Britain and the Commonwealth.
Russ Allison is one of the authors of the 4th (last, 1985) edition of
C.Culling's excellent textbook, and he published significant original
papers on waxes from the mid-1970s up to 1998. He compared many
commercial and extempore formulations (more than a hundred, if I
remember rightly) using physical measurements of the variation in force
resisting the passage of the block face across the blade, scanning EM to
see how solidification of the wax deformed fine structure, and
determination of the rate of infiltration of tissue, and how this was
affected by temperature, MW of the wax, additives etc. His bottom lines
were that:\
1. Additives to paraffin, declared or secret, have no effect on cutting
or the appearance of stained sections. This conclusion dismissed many
unprovedc claims for additives to paraffin wax. The secret polymer
additives (often with short lifespans, according to the salesmen) do
not help in any way.
2. Infiltration by paraffin is somewhat quicker if the wax contains some
DMSO (= dimethyl sulphoxide, a solvent miscible with nearly everything).
All but the most recent of Russ Allison's papers were published in a
British journal that has changed its name too many times. Some are in
the British Journal of Medical Laboratory Science, and others are in
Medical Laboratory Sciences. The volume numbers are continuous, dating
from the good old Journal of Medical Laboratory Technology, which
contains some real classics in the field of Histotechnology.
John A. Kiernan
Anatomy & Cell Biology
University of Western Ontario
London, Canada N6A 5C1
------
Igor Deyneko wrote:
> Dear Histonetters! I was just wondering, can someone advise a good
> embedding paraffin for me? I embed tumors mostly, and occasional
> livers and pancreas, and very rarely colon. The 1 I'm using right now,
> Richard-Allen #6, I'm not crazy about. I am looking for one preferably
> with polymers. Has anyone ever used the SurgiPath Embedding paraffin
> and what are your reflections?
> Thank you.
> Igor Deyneko.
> Infinity Pharmaceuticals
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