[Histonet] RE: Processing Problem

Tue Sep 17 10:49:57 CDT 2013

Sandra

Sandra

We section large porcine skin samples all of the time.  When there are lesions present we normally like to bisect after fixation, that way we get a nice even edge to section.  You want to bisect slightly uneven (1mm) so once you trim in you are at the center of the lesion.  It's very important that you try to capture sections that are at the center of the lesion, so great care must be taken in grossing, embedding and trimming in samples like these.  These samples heal from the outside in so if sectioning is not consistently in the center you can bias/skew the results.  Are you sure that that samples are 2mm x 2mm x 1mm or did you mean to say 2cm x 2 cm x 1cm that makes more sense to me.

These samples will need to remain in fixative for at least 24 hours prior to you bisecting  and trimming, after you bisect them I would continue to fix for an additional 24 to 48 hours.  If the lesion is a punch it will be about 8 mm in diameter, your trimmed piece of tissue should be  2cm x 5-6mm x 1cm (LxWxD).  We process these types of samples on a longer processing cycle.  1.5 to 2 hours per station with  additional  absolute and  xylenes steps so there are 3 absolute and 3 xylenes and 4 paraffins .  If they are processed well they should stay on the slide when they are sectioned when using a good plus slide.

Good Luck

Liz

Elizabeth A. Chlipala, BS, HTL(ASCP)QIHC
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-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Sandra Cheasty
Sent: Tuesday, September 17, 2013 9:26 AM
To: histonet <@t> lists.utsouthwestern.edu
Cc: Sandra Cheasty
Subject: [Histonet] Processing Problem

Hi All,

                I need help with two issues. I have a researcher who is sending us porcine skin, about 2mm x 2mm x 1mm tall.

Issue 1: There is a lesion in the center, and although he wants the skin sectioned through the lesion eventually, he says if he bisects the chunk of skin before fixation, the lesion becomes distorted. So, he is fixing them in the 2x2x1 chunks, and the 10% formalin (and subsequent processing reagents) are not penetrating. Does anyone know of either a more penetrating fixative or a less distorting one so we can bisect the skin before fixation?

Issue 2: Even on smaller sections that fixed and processed well, we are having issues with the porcine skin sections staying on the slides. We use Superfrost Plus slides, drain them, air dry them overnight, and then they go on the "Extra Oven" program on the stainer. (25 minutes in the oven.) Any suggestions on other slides, drying techniques to try?

My background is that of a certified Histologist for 30 years, with experience in many labs in various parts of the country. This research project has me stymied!

Thanks for your help!

Sandy

UW Madison

School of Veterinary Medicine

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