Catherine,

What kind of plastic are you using?  Poor infiltration of a glycol
methacrylate, like JB-4 can cause these kinds of problems.  Poor
infiltration of epon-like plastics just don't set up hard, at least in my
hands.

Karen Pawlowski
Sr. Res. Assoc. UTSW Dept. of Otolaryngology/
PhD Candidate. UTD

On Mon, 5 Oct 1998, Catherine Johnson wrote:

> Dear Histonetters:
>
> We've had a problem with our plastic embedded nerve biopsies on and off.
> The tissue sections are stained with MAB or Toluidine blue.  Often times,
> it looks like there has been poor penetration of the fixative or possibly
> other solutions during processing.  Sometimes the sections are difficult to
> read because there is so much artifact.  Artifacts include poor penetration
> of the stain, distorted cross sections of myelinated fibers, and wrinkles.
> Our EM technician has a tendency to always blame it on the fixative, so she
> makes an effort to make sure the fixative is always fresh.  We've also
> started slitting the perineurium with a razor blade before dropping the
> specimen into fixative in hopes of improving penetration, but these methods
> have not helped consistently.  I'd appreciate any recommendations all you
> plastics experts might have to remedy this frustrating problem.
>
> Thanks in advance,
>
> Catherine Johnson
> University of Minnesota Neuromuscular Lab
>
>
>