[Histonet] question of the day - embedding

[Joseph Saby]

Tracy-

Where I used to work (at a place that shall remain nameless), we always kept our tissue being embedded in hot paraffin in the holding chamber.  Most of my work has been with animal tissues.

Where I work now, we don't.  And I do bellieve you are right.  If the tissues remain in hot paraffin, the heat transfer rate is very high, and the tissues continue to "cook" even when the chamber temperature has been reduced (as close as feasible) to the melting point of the paraffin.  I have seen little effect on the tissues of longer-than-I-would-like time in the holding chamber without paraffin.  Without the paraffin, the tissues do not get that direct heat from the melted paraffin and survive delay much better.

In short, I agree with you.  Not keeping the tissue in hot paraffin does not only not damage those tissues, it allows more flexiblity in your embedding times.

Joe Saby, BA HT




________________________________
From: Tracy Bergeron <tracy.bergeron <@t> biogenidec.com>
To: histonet <@t> lists.utsouthwestern.edu
Sent: Tuesday, February 17, 2009 4:14:46 PM
Subject: [Histonet] question of the day - embedding

Hi all question/dilemma of the day.

        I have been of the view that the longer tissue sat in melted 
paraffin the harder it got, especially animal tissue.  So with that said, 
for the past nearly 10 years I have not used melted paraffin in the 
holding chamber of the embedding center.  I just keep the chamber warm, 
and work that way.  Thus keeping the tissue from continuing to cook and 
harden in the wax.

        Everyone else I am currently working with has never seen the 
method I use, and firmly believe that this causes harm to the tissues if 
they are not in paraffin.

        Thoughts ideas etc.  I am dying to know if I am the only one that 
worries about length of time that animal tissue sits in paraffin.

Thanks.

Sincerely,
Tracy E. Bergeron, B.S., HT, HTL (ASCP)
Associate Scientist III, Pathology
Comparative Pathology Laboratory
Biogen Idec
14 Cambridge Center
Cambridge, MA 02142
Direct:  617-914-1115
Fax:  617-679-3208
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