Dear Steve, This is a good tip. We use this technique, (steps 6,7 and 8)
when embedding curettes and POC's etc, but with foam pads. David.

David Taylor
Laboratory Manager
Drs King & Mower
Adelaide, Australia


-----Original Message-----
From: Steve Machin UK [mailto:stevemachinuk@yahoo.co.uk]
Sent: Sunday, 5 August 2001 22:56
To: Histonet Histonet Histonet
Subject: Re processing Tiny Biopsies, esp. paste like material


I have a trick to share with you which enables us to process tiny
fragments of tissue too small to pick up.
CellPath sell biowrap paper which remains stiff after processing and
will hold tiny fragments of material, e.g. bone marrow aspirates.
The paper is made for wrapping small samples and I'm sure other
people sell similar material.

1. Cut the end off a plastic dropping pipette.
2. Suck up the tissue fragments.
3. SLOWLY drop the sample onto the biowrap paper which is placed onto
a dowmflow bench or a wad of absorbant material.  The excess fluid
will be drawn away and leave the sample in a small spot.  The slower
you do this the smaller the spot will be.
4. Wrap up the paper and process.
5. At embedding, unwrap the paper and make sure the wax on it remains
molten.
6. Keep a mold hot and put in the paper specimen-side-down.
7. Keep the mold hot until the wax is melted both above and below the
paper, add a little wax to the mold at this stage.
8. This is the hard bit.  When melted, quickly transfer the mould and
paper to the cold plate and press the paper into the mould with one
finger. AS SOON as the wax begins to set, peel the paper off the
mould and, hey presto, all the tiny bits of tissue are stuck to the
mould and not the paper.
9. Add more wax to the mould and remelt.  Allow the bits to settle to
the bottom on the mould and then set the block ready for sectioning.
10. Make sure the microtome chuck is perfectly aligned or you you
will trim away the sample.  For a tip on aligning the mircotome chuck
see my homepage on histonet.

Best Wishes
Steve Machin UK

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