All three of the neuropathologists at our institution in the last dozen or
so
years do NOT want muscle clamps used for muscle biopsies.

The clamps "clamp" the ends of the muscle, thereby distorting and
destroying that part of the muscle, so it can't be used for diagnosis,
either FS enzyme histochemistry, fixed-paraffin histology stains, or
EM.

The purpose of the clamps is to supposedly keep the muscle from
contracting. Contraction artifact causes the muscles to look
(on cross-section) larger and rounder. This may be mistaken for
a disease.

However, if the muscle biopsy is clamped, some of the muscle sarcomeres
(individual actin-myosin units) will continue to contract, at the expense of
other sarcomere units, which will be over-stretched. So these
over-stretched units look thinner on cross-section. So a clamped muscle
will have contraction artifact and over-stretching artifact.

So what we do is have the surgeon remove the muscle, and simply
place it on a gauze pad slightly dampened with saline. The gauze is
wrapped around the muscle, and brought down to histology immediately.

We let it set on the counter at room temperature in the damp gauze for
30 minutes, before it is grossed into pieces for EM, IM and FS.

The 30 minutes resting time at room temperature allows the muscle
to "relax", so that there is less contraction artifact. There is no loss of
enzyme activity during this 30 minutes.

If you think it is going to be longer than 30 minutes before someone is
available to gross the muscle (such as all pathologists are at a meeting
or at lunch), place the tissue (still in the damp gauze) in the
refrigerator.
This will slow down any loss of enzyme activity. Do NOT place the
tissue in the freezer or the cryostat to slow down the enzyme loss. The
tissue will freeze very slowly, and there will be a LOT of ice crystal
artifact, such that diagnosis will probably NOT be possible.

Hope this helps.

Peggy A. Wenk, HTL(ASCP)
William Beaumont Hospital
Royal Oak, MI 48073

----- Original Message -----
From: "Richard Piotto" <richpio@hotmail.com>
To: <histonet@pathology.swmed.edu>
Sent: Saturday, March 17, 2001 10:03 AM
Subject: Muscle Biopsy Clamps


> Hi All
>
> Getting Muscle biopies started and having trouble finding the specific
> clamps for the procedure. If anyone has information on companies that
supply
> these items I would be grateful.
>
> Cheers
> Richard
> _________________________________________________________________________
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>
>
>