RE: Cornflaking

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From:garygill <> (by way of histonet)
To:histonet <>
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Plain tap water works equally well.  Corn flaking, aka brown artifact, is
air trapped on the surface of superficial cells almost exclusively.  It
precipitates when xylene evaporates, leaving behind the exposed surface of
these cells, which are coursed by fine grooves to promote cell attachment.
Anything that promotes xylene evaporation promotes corn flaking.  Prolonged
draining between rinses, coverslipping multiple slides at a time,
coverslipping under a fume hood in which air enters the face at 75-100
linear feet per minute.

To prevent corn flaking, coverslip one slide at a time.  Do not drain the
slide thoroughly.  Try putting a chemical splash shield at the front edge of
the fume hood and coverslip behind it.  The shield diverts the incoming air
and creates a quite zone where evaporation occurs more slowly.

Since water removes the brown artifact, it is clear that this artifact does
not occur before staining.  Indeed, even if it did, it would be removed by
the water rinses in the front half of the Pap stain and it would never be
seen.  Since tap water destains the OG and EA dyes but not hematoxylin,
restaining is required only for OG and EA.

It is not necessary to destain the slide, as the artifact is air and not
stain.  Remove the cover glass.  Pass the slide back from xylene, to
absolute alcohol, to water.  Microscopically check the slide to verify the
removal of the artifact, then restain beginning in OG.  A preceding rinse in
alcohol is unnecessary.

Gary Gill

-----Original Message-----
From: []
Sent: Sunday, January 24, 1999 10:09 AM
Subject: Cornflaking

Our lab experiences cornflaking on occassion.  We use the following

1.  Destain the pap smear slide.
2.  Let stand in glycerin for 5 - 10 minutes.
3.  Rinse in running water for 5 - 10 minutes (enough to remove any
4.  Restain the slide.

This works for us, good luck!!


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