[Histonet] Thumbnail list of muscle biopsy errors

From:"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. .                

<< Previous Message | Next Message >>