Re: Wood sectioning with Carbowax

From:Gayle Callis

Try vacuum infiltration with heat over a long period of time (2 changes, 2
- 4 hours each change, even overnight).  If you have a vacuum oven, that
will help or put your vacuum desiccator in a hot incubater (melting point
of Carbowax/paraffin). You could also try a harder paraffin, Tissue Prep 2
from Fisher is a possibility, then embed in the same paraffin.  

You can mount a block to another block of wood ie chuck (use a hard wood,
cut grooves/grids to increase surface area and grip and so it fits into the
backside of an embedding mold). Make sure this chuck is heated.  Embed your
paraffin infiltrated cherry wood sample into a mold with melted paraffin,
and place the heated wood "chuck" to the backside, let it all cool
together, then you can clamp the outer wood block directly into a
microtome.     

Have you considered working with a plastic, carbowax or paraffins are not
as hard as the wood, and may not be the correct support for hard material
since you want to match the hardness of the support media to the hardness
of the "tissue", in your case, cherry wood.  Polymethylmethacrylate is a
possibility, but it requires a tungsten carbide knife for cutting, pricey
too.  If blocks of wood are very tiny, yours a bit large for GMA ie glycol
methacrylate might work, but you still need a very sturdy sharp blade to
cut through that tougher wood sample. 

Tell us what you are looking for in cherry wood?  Very interesting when
someone from plant world asks questions!! 

 

At 02:19 PM 2/25/02 -0500, you wrote:
>Hello everyone...
>I'm new to this list, but already I have found it very useful!  I have a 
>couple problems that I would like to pose a question to the arena of 
>experts.  I am working with cherry wood sections and infiltrating them with 
>Carbowax instead of paraffin.  However, I am having a heck of a time trying 
>to get the sections to (1) stick to the wood block....I am so frustrated 
>that I want to just nail it to the block, and (2) trying to get sections 
>that don't crumble.  I think the answer to my 2nd problem is that I need to 
>get the carbowax to infiltrate better, but how can I soften the extrememly 
>dense, hard wood?  Any helpful hints on getting the sample to stick to the 
>block?  They are about <1 cm in diameter, and about 2-3 cm long. 
>
>Thank you in advance for your help!
>
>Mercy Olmstead
>Michigan State University
>
>
>
>
Gayle Callis
MT,HT,HTL(ASCP)
Histopathology Supervisor
Veterinary Molecular Biology - Marsh Lab
Montana State University - Bozeman
19th and Lincoln St
Bozeman MT 59717-3610

406 994-6367
406 994-4303 (FAX)





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