Re: Wavy sections

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From:Lynn Gardner <> (by way of histonet)
To:histonet <>
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Good morning. The following are some suggestions on things we looked at and
changed when we were experiencing this problem.

The first thing I would check is what is the melting point of your
paraffin, should be written on the box or MSDS. Your temperature on your
processor seems quite high usually the temp should be for a 56-58 degree C
melting point the temp on the processor should be set at 57 degrees C. The
other thing is how long you process your tissues in the paraffin, it should
be no more than 2.5 hours total time.

The second thing I would look at is how thick the tissue sections are on
the days you are having problems. If  they seem thicker on those days you
may want to gross them thinner they may not be getting proper infiltration
with the processing chemicals. Also how long did to tissues fix is there a
variation in the fixation times. If there are make sure to find out how
long the "good" tissues fixed prior to processing and use that as a
standard and show the physicians why you want to do that, show them a good
slide and a bad slide and help them understand why the tissue will be
delayed a bit.

The third option is to look at the way the tissue is being cut if the skin
edge is horizontal _______ to the knife try changing it to the skin edge is
vertical to the knife  | or if it is the other way around try switching it.
Sometimes it is the way we cut the tissue that causes that problem.

And Finally it may have to do with a combination problem first due to the
excessive heat in you processing paraffin and then not enough heat in your
waterbath. We use a two waterbath technique that helps to float out tissue.
We use a waterbath at room temperature to float our tissue out and pick it
up on a slide. We then place that piece on a hot water bath usually between
54 and 56 degrees C. Going from the room temp to the hot helps the paraffin
expand better thus eliminating the waves. We work with corneal tissue and
since we have used this technique we rarely see waves.

Unfortunately without seeing the slides and tissues I can only offer these
suggestions. One or a combination of these suggestions should work for you.
I wish you well in your hunt for an answer.

Please let me know if I can be of further assistance.

Lynn Gardner, HT(ASCP)
Supervisory Research Assistant III
FC Blodi Eye Pathology Laboratory
The University of Iowa
233 MRC
Iowa City, IA 52242-1182
Phone: 319-335-7095
Fax: 319-335-7193

At 04:40 PM 12/14/98 -0600, you wrote:
>Looking for suggestions on the cause of wavy sections, so bad that we are
>unable to focus under high power.  This has happen out of the blue without
>changing any procedures.  I am cutting all skin, some look good,  but this
>problem seems to affect the staining ex. muddy appearing, poor contrast and
>understaining.  All temps. are with norm. except of a paraffin bath on
>processor is 64 C. Sections have been good 2 days a week then progressively
>get worse.
>Thank you

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