paraffin section compression

From:Carla M Aiwohi <>

Hi everyone,

Our lab was sent blocks of fish tissue (liver, spleen and heart) embedded
in Paraplast X-tra (aka Tissue-Path).   I am trying to cut sections at 4
microns.  They are compressed when cut and paraffin around the tissue edges
doesn't want to expand on the water bath causing lots of wrinkles(on
tissue, not me yet).  Here's what I've tried so far:
- after sectioning, cutting around the tissue radially and trying to smooth
out with brush (didn't help much)
- adjusting the knife angle (cuts best at 3 deg.)
- raising water bath temp. (49C )
- soaking blocks in ice bath from 10 min. to half day
- changing disposable knives constantly
- slowing my cutting speed (sectioning done manually)

Slides will be given to participants at a workshop, so I'd like to make
them as perfect as possible.
Please help-  I am running out of time, tissue and ideas.

Thank you,

Carla (Aiwohi) Conway
Western Fisheries Research Center
Seattle, WA

P.S.  Do others have trouble cutting Paraplast-embedded tissues (or is it
just me)?

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