coverslipping "dehydrated" or "dry" sections

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From:Gayle Callis <> (by way of histonet)
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I presume one is permitting the section to air dry thoroughly?

Have done this often, without bubbles but one needs to make sure the
section is totally dry.  This is often done with some toluidine blue
stained sections that never goes through graded alcohols to "dehydrate"
the section, what we all do before going into a clearing agent before
a routine coverslipping. This was done with this particular stain to
avoid differentiation or removal of the t blue from the section, decalcified
bone.  This is also the technic for Verhoeff's Van Gieson, where the section
is blotted and allowed to dry, preventing removal of the Van Gieson
counterstain by alcohol AND xylene.

Another trick is to thin the mounting media a bit, often too thick anyway!
and coverslip from the edge of slide, but controlling the speed of
coverslip as it goes over the section SLOWLY.  It also helps to not put a
drop, but spread the mounting media in a line, I do this on the slide
below section, then add coverslip with thumb and forefinger, to capture
edge with media, then letting it down slowly.  One can also do this
with a forceps.  If the edges under coverslip do not have mounting media,
dip the forceps in clearant, xylene or toluene, and let this flow under the
coverslip, allows the mounting media to flow into "bare spots".   This did
not seem to thin the mounting media further.  At least this is a way to
avoid the leaching of some stains in clearants.

All our GMA sections coverslipped this way to avoid the ugly  parched earth
cracking of plastic by xylene.

I don't think one can coverslip a "dehydrated" slide if alcohol is still
there, it would have to evaporate first and the last alcohol may still have
traces of water, so "dehydration", is not complete, giving rise to air
bubbles as it evaporates from under the coverglass.  I guess I am trying
to understand the exact technic being done here, hence the "dehydrated" out
of alcolhol, or "air dried".

How to coverslip the slides, let me count the ways, in fact, how many ways
have you done this, a Y2K challenge!  and automated coverslippers do not

Gayle Callis, what a tirade on coverslipping!  Welcome to Y2K.

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