These are different RE: [Histonet] Methylmethacrylate to LR White?

From:Gayle Callis

LR White is not the same glycol methacrylate although it does contain some 
type of methacrylate resin.

It's chemical components are

80% polyhydroxy substituted bisphenol, a dimethacrylate resin
19.6% C12 methacrylate ester
Catalyst is 0.9% benzoyl peroxide

One difference is LR white, although low viscosity, can be used for 
electron microscopy while glycol methacrylate is not advisable for EM, it 
"gums" up the 'scope.

I was never successful at removing polymerized methyl methacrylate (MMA) 
from  internal portions of a bone.  However, I did remove it from external 
bone surfaces after a rapid polymerization took place.  Bubbled MMA was 
chipped and ground away first, then the remaining block was immersed into 
pure methacrylate monomer.  The methacrylate monomer acts as MMA's own 
solvent. After the bubbly mess was gone from the outside, but not the 
inside of the bone which was reembedded into MMA.  MMA can be removed from 
thin sections (3  to 5 um, maybe thicker) with other solvents, even the 
monomer and 60C xylene was suggested by Neil Hand.  Chloroform may not be 
advisable due to its carcingenic nature.

Gayle Callis HTL, HT, MT(ASCP)
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717

  At 09:18 AM 12/15/2006, you wrote:
>Methyl methacrylate can be removed with xylene, but glycol methacrylate can
>not ever be completely removed, I believe LR White is a glycol methacrylate.
>-----Original Message-----
>[] On Behalf Of matt
>prideaux (RI)
>Sent: Friday, December 15, 2006 5:02 AM
>Subject: [Histonet] Methylmethacrylate to LR White?
>Hi all,
>I need to remove the methacrylate surrounding some bone samples (I was
>told that a 50:50 solution of xylene and chloroform would do the trick).
>The problem is that I want to re-embed the samples in LR White once the
>methacrylate has been removed. Does anyone have any experience in this
>or knows if it is possible? I need to cut 10 micron thick cross-sections
>of mouse tibiae and these have failed to adequately infiltrate with
>methacrylate. With LR White being less viscous I was hoping that it
>would infiltrate better.
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