I can understand your question from the clinical point of view where you want to cut the section, fix, stain and then examine for immediate diagnosis. Not everyone does this.
There are many of us, both in clinical and research, who do frozen sections for other than diagnostic reasons. We often need to do immunofluorescent or enzyme immunohistochemical staining (chromogenic) for antigens e.g. CD4, CD8 and many others that will not withstand the kind of fixation you describe. Often we need to do cold acetone fixation or some other solvent fixation for this purpose. In that case, our histologic interpretation is based on a different handling and fixation of a fresh tissue frozen section, and in our case, we cannot just cut and immerse into alcohol. One, the fixative e.g. alcohol is not going to work for our antigen Two, we perform cryomicrotomy on a piece of tissue, collecting as many as a hundred sections, often serial and store the sections until staining (immunostaining in particular) can be performed. Air drying is a form of fixation, and the act of picking up a section onto a slide has been referred to as "flash drying". The antigens we need to see are better when air dried overnight, then fixed with either acetone or acetone/alcohol (in the case, for murine CD markers). Often air drying the section at RT and then fixing with acetone, and storing these fixed sections in a -80C freezer is very acceptable. If I were in a clinical setting and doing a routine H&E, I probably would do exactly as you do now. It is a matter of application. In our case, immersion immediately into a fixative is not optimal for our immunofluorescent or enzyme immunohistochemical results. If we want to see or identify where we are in a sample, we do exactly as you do, section and immerse into fixative, and then do a rapid H&E stain when we can or within a few minutes. We frequently immerse a frozen section into neutral buffered formalin and fix later in the day, week or whenever to have excellent morphology and staining results with an H&E. I hope this clarifies some parameters of performing cryotomy and staining versus how you do it. Gayle M. Callis HTL/HT/MTA(ASCP) Bozeman MT -----Original Message----- From: histonet-boun...@lists.utsouthwestern.edu [mailto:histonet-boun...@lists.utsouthwestern.edu] On Behalf Of Tench, Bill Sent: Tuesday, August 24, 2010 5:07 PM To: Histonet@lists.utsouthwestern.edu Subject: [Histonet] preparation of frozen sections So as a pathologist, i have to ask you why you would want to air dry a section? From a diagnostic perspective, we consider air dried samples unacceptable in my lab. All of our standard histologic interpretation is based on fixed sections. So, why not drop the slide in a jar or ETOH and keep it there until you are ready to stain? Bill Tench Associate Dir. Laboratory Services Chief, Cytology Services Palomar Medical Center 555 E. Valley Parkway Escondido, California 92025 bill.te...@pph.org Voice: 760- 739-3037 Fax: 760-739-2604 [None] made the following annotations --------------------------------------------------------------------- Confidential E-Mail: This e-mail is intended only for the person or entity to which it is addressed, and may contain information that is privileged, confidential, or otherwise protected from disclosure. Dissemination, distribution, or copying of this e-mail or the information herein by anyone other than the intended recipient is prohibited. If you have received this e-mail in error, please notify the sender by reply e-mail, and destroy the original message and all copies. --------------------------------------------------------------------- _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet __________ Information from ESET Smart Security, version of virus signature database 5394 (20100824) __________ The message was checked by ESET Smart Security. http://www.eset.com __________ Information from ESET Smart Security, version of virus signature database 5394 (20100824) __________ The message was checked by ESET Smart Security. http://www.eset.com __________ Information from ESET Smart Security, version of virus signature database 5394 (20100824) __________ The message was checked by ESET Smart Security. http://www.eset.com _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet