[Histonet] Thumbnail list of muscle biopsy errors

[George Cole]

1.	Even when a substantial cubic cm piece of muscle was sent, tiny
1 and 2 mm bits of tissue were sectioned. 
2.	Gum Tragacanth was used to position the tissue  Tragacanth helps
get good sections., but it is a bit messy and it is itself a form of
sugar which tends to confound testing for abnormal glycogen.
3.	To hold the tissue for freezing odd heavy metal plugs were used
with gum tragacanth and pip of muscle on top of it to insert into the
Isopentane and liquid nitrogen.  The mass of metal commands the edge of
the cold effect, which tends to add to the threat of ice crystals.
4.	Gum tragacanth surrounding bits of tissue are placed on cork to
freeze.  Cork is a very good insulator and adds a bit to the chance of
ice crystals on the underside of the tissue.
5.	Isopentane is cooled in the  liquid nitrogen until it gets a
little thick.
6.	The tissues are sectioned in their native shape which will
almost always be odd, with planes and peeks of tissue. Sections are
hardly at their best as they almost always twist and curl onto the knife
due to the erratic angles presented to the knife. You can see the
twisting wayward sections coming onto the knife in some of the muscle
text books.
7.	Sections---for some strange reason, perhaps due to the
suggestion of a tricky leprechaun, who is still laughing at us for
taking him  up on it----are picked up on cover slips.
8.	Amounts of reagents are kept to the minimum----barely covering
the sections on the slide.  
9.	 The usual buffer for ATP-ase mixtures continues to be the
sodium pentobarbital buffer in the literature.  This takes a controlled
substance permit to procure and it's not worth the trouble.  It's not
the best buffer for ATP-ase.
 
Suggestions on better ways will follow. This is already a lumpy message.
.                 
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