[Histonet] Methacrylate with Re: automated tissue processor

From:Gayle Callis

By methacrylate, you mean methyl methacrylate?

If so, the answer is No (so far no one has developed a processor for MMA 
protocol) but you can use an automated processor through all the 
dehydrationa and clearing steps as long as you do NOT use monomer as a 
clearing agent.  We used our VIP to dehydrate through alcohols and clearing 
agents but programmed out all the paraffin steps. After the last clearing 
agent,  undecalcified bone samples are removed for hand processing through 
infiltration mixtures.  Since infiltration was done in a refrigerator at 4C 
to prevent unexpected polymerization of partially infiltrated samples,  we 
simply used a Wheaton O ring vacuum dessicator with inhouse water vacuum 
(very handy!) or vacuum pump inside a hood  with each change of 
infiltration mixture (we had three) and vacuum and watch bubbles come off 
generally for about 4 hours, then release and put the samples in a 
refrigerator in tightly capped containers, then remove and bring to room 
temperature AFTER desired infiltration time, and change mixture, repeat 
this process.

We processed 1 cm thick bone slabs with this method, taking extremely long 
times for dehydration/clearing - and the VIP never  missed a beat other 
than having to top off alcohols and clearing agents due to 
evaporation.  Monomer was never put on this instrument.

No company has developed an automated processor for methyl methacrylate but 
more importantly, you do NOT want to breathe the fumes as methyl 
methacrylate monomer is a toxic substance very damaging to Central Nervous 
System.  If you smell it, you are exposed and one should always do any 
handling/infiltrations/vacuuming inside a good fume hood.  Protect yourself 
and others from fumes - the act of changing the monomer out of a processor, 
disposal, etc would be a messy, smelly process.  Besides you do not want 
some of the infiltration mixtures on the processor, if they polymerize, it 
would be a disaster.

I will be happy to send you a very nice MMA protocol per Sterchi 
publication where the infiltration mixtures are NOT thick, gooey 
consistency, and you get excellent results for infiltration, embedding and 

     At 08:44 PM 8/22/2005, you wrote:
>Does anyone know if there is an off-the-shelf automated tissue prcessor that
>can be used for methacrylate embedding for 2-3 cm bone samples?
>Specifically, I am looking for something that has no heating capable of
>operating at ambient temps with the ability to draw pulsatile vacuum for
>better polymer penetration.
>Thanks in advance histonet users!
>Histonet mailing list

Gayle Callis
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University - Bozeman
PO Box 173610
Bozeman MT 59717-3610
406 994-6367
406 994-4303 (FAX)

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