RE: [Histonet] Excessively Wrinkled sections

From:"Nick Kirk"

I've always floated sections out on a water bath in the low to mid 50s with
hardly ever any problems. The key is to use de-ionised water which will
reduce bubble formation and to give the water bath a tap (or thump depending
on your mood) every now and again to release any bubbles that may have
formed on the base or sides to allow them to float to the surface and pop
Floating out at that temperature is also a good indicator of how well
processed your tissue is, as poorly processed tissue will "explode" across
the water bath and in my book, if it does that, it needs to be re-processed.
Floating out at a lower temperature will still remove the wrinkles but it
takes a lot longer and you have to weigh up the risk of bubbles against the
extra time needed to complete the task.
If your department isn't that busy, then the lower temperature is an option.
If, however, you work in a busy department, you probably can't afford to sit
around twiddling your thumbs all day waiting for sections to flatten out.
It's a case of Risk Assessment and in the labs I've worked in over the
years, we've always opted for the hotter option with no problem.

Nick Kirk
Hinchingbrooke Hospital

-----Original Message-----
[]On Behalf Of John
Sent: 27 September 2003 05:31
To: Albert Grobe
Subject: [Histonet] Excessively Wrinkled sections

Is it really OK to float out sections on water
that is "a couple degrees below the melting temp
of the wax"? Ribbons of 58C wax extend nicely
on water at 40-45C. I've never dared to float
ribbons on a water bath in the 50s because I've
seen the bad effects of high temperature when
doing on-the-slide flotation on a 55C hotplate.
That's the way I was taught, by technicians
who were skilled enough to do it well.

Hot water under a paraffin ribbon yields up
its dissolved air in the form of many tiny
bubbles. These form under the sections and
cause lousy staining for obvious reasons.

When wax melts in the presence of even a thin
film of water under a ribbon of sections you
have a recipe for disaster. If you can cut,
float and mount "ideal" sections from water
that's only 2C below the nominal melting
point of the wax, please post detailed
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
Albert Grobe wrote:
Ideally, the waterbath should be a couple degrees below
the melting temp of the wax but some fine adjustment is
sometimes necessary.  I have had the same problem in
the past, and raising the temp has helped.

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