Two comments
First is that with mineralized tissues there will be a tendency for some
regions with high mineral content to act as focal points for
polymerization to start and consequently this often results in bubbles
starting at that point.
The second is that I have often wondered if thick solutions of
methacrylate and other resins should be subjected to ultrasonic
treatment before use. We used this method when mixing Epon and other
resins for electron microscopy and it virtually eliminated bubble
formation around tissues. Just a thought.
Barry

-----Original Message-----
From: histonet-admin@lists.utsouthwestern.edu
[mailto:histonet-admin@lists.utsouthwestern.edu] On Behalf Of louise
renton
Sent: Friday, December 12, 2003 4:59 AM
To: histonet@lists.utsouthwestern.edu
Subject: RE: [Histonet] polymerization problems


Dear Tom,

Well, this is my 2 cents (South African) worth:

1. I have, as yet, not been able to get the stuff to polymerise at cold 
temperatures. I have had very good sucess at RT, although with such
large 
tissues, trial and error as well as judicious advice from fellow 
histonetters, it is  recommended that the specimen is "layered" with 
embedding solution and allowed to polymerise over a few days. Otherwise 
unsightly and potentially bubbly and uncutable blocks result.

2. I have found that, because the 2  embedding solutions are so viscous
that 
they must be well mixed before use. I generally stir mine for about 20 
minutes on a magnetic stirrer before pouring into the mould. (do this in
a 
fume hood)

3. Heraeus Kulzer have a very nice technical assistant in Germany who
has 
been very helpful in the past. If all else fails  get hold of her for 
further insights. She is Ulrike Leins at: Ulrike.Leins@t-online.de


best Regards

Louise Renton
Bone Research Unit
MRC
Johannesburg
South Africa
Tel & fax +27 11 717 2298
"Time flies like an arrow, fruit flies like a banana"





----Original Message Follows----
From: "Tom Schaer" 
To: 
Subject: [Histonet] polymerization problems
Date: Wed, 10 Dec 2003 09:32:05 -0500

Dear Histonetters:

I am going to try again, realizing that not many have vast experience
with 
embedding large specimen with technovit 9100 yet.  Maybe someone may be
able 
to share some pointers for a non-profit lab?

Essentially, we fail to successfully polymerize med fem ovine condyles
in 
approx 100ml jars.  Tried at -15C with no change in solution consistency
for 
a week; then brought it up to -2C still no change over three days.  Jars

were "vacuumed" and set in refrigerator / freezer.  I am at the of my
rope 
of troubleshooting.

Thanks for any pointers.

Tom
------------------------------------------
Thomas P. Schaer, VMD
Assist. Prof. BIOMED, Drexel University
Comparative Orthopaedic Research & Tissue Engineering Department of
Clinical Studies University of Pennsylvania New Bolton Center 382 West
Street Road Kennett Square, PA 19348 tel. 610-444-5800 (x6261 office)
tel. 610-444-5800 (x6131 lab) fax. 610-925-8100
tpschaer@mail.vet.upenn.edu

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