I did an experiment about 10 or 12 years ago, where I cut the sections and stained them at various intervals: Day1, Day 15, 1 month, 3 months, 6 months, 1 year. Before staining: Set of slides were allowed to sit at room temp (RT). Set of slides were stored at 4C. Set of slides were vacuum sealed and stored at RT. Set of slides were vacuum sealed and stored at 4C.
Slides stored at 4C consistently stained well, with a slight variance in staining after 1 year. Did not matter weather they were vacuum sealed or not. Slides left out at RT did not fare so well. Staining variability was noticed after 1 month. When the slides were stained after one year, signal was almost eliminated. Variability and loss of antigenicity was observed with the vacuum sealed slides as well. I did this experiment for just one antibody which was being extensively used at the time for one of our projects. It could be that other antibodies fare mach better under RT conditions, but why take a chance? We keep all of our control slides at 4C. Blocks are kept at RT. Thanks Dusko Trajkovic ________________________________ From: "Morken, Tim" <timothy.mor...@ucsfmedctr.org> To: Helen Fedor <hfe...@jhmi.edu> Cc: "histonet@lists.utsouthwestern.edu" <histonet@lists.utsouthwestern.edu> Sent: Thu, November 4, 2010 9:09:16 AM Subject: RE: [Histonet] unstained paraffin tissue slides storage--why cold? Helen, did you write a paper from that study? Tim Morken Supervisor, Histology, IPOX UCSF Medical Center San Francisco, CA, USA -----Original Message----- From: histonet-boun...@lists.utsouthwestern.edu [mailto:histonet-boun...@lists.utsouthwestern.edu] On Behalf Of Helen Fedor Sent: Thursday, November 04, 2010 8:56 AM To: sgoe...@xbiotech.com; Emily Sours Cc: histonet@lists.utsouthwestern.edu Subject: RE: [Histonet] unstained paraffin tissue slides storage--why cold? The study that we did showed that the staining on freshly cut slides from a block stored at room temperature was in fact not as good as slides that were sectioned 5 years earlier and stored at -20. Therefore the blocks should be stored in the cold as well. The tissue is degrading in the block and on the slides and the cold does slow down the process. The fixation in lots of the tissue is not optimal. Fixing for 48 hours will definitely be better than the current fixation practices going on in most clinical labs, if what you want is the best tissue preservation possible. But most of us do not have that option. Helen L. Fedor Tissue Microarray Lab, Manager Prostate Spore Lab, Manager Johns Hopkins University 600 N. Wolfe St, | Marburg Room 406 Baltimore, MD | 21287-7065 -----Original Message----- From: histonet-boun...@lists.utsouthwestern.edu [mailto:histonet-boun...@lists.utsouthwestern.edu] On Behalf Of sgoe...@xbiotech.com Sent: Thursday, November 04, 2010 11:21 AM To: Emily Sours Cc: histonet@lists.utsouthwestern.edu Subject: RE: [Histonet] unstained paraffin tissue slides storage--why cold? -70 or -80 seems a little extreme to me, that's why I always just leave them in a normal freezer (-20). I think the main point of doing this from what I understand is so that the antigens stay "viable". I know over time they can degrade and so your stain won't work with some antibodies. The weirdest part to me has always been that you don't have to store the blocks this way. So I think that was your question, if the blocks aren't stored in a freezer why store the slides? Won't the antigens in the blocks start to degrade as well? This is a question I would like to know the answer to as well... Sarah Goebel, B.A., HT (ASCP) Histotechnician XBiotech USA Inc. 8201 East Riverside Dr. Bldg 4 Suite 100 Austin, Texas 78744 (512)386-2907 -------- Original Message -------- Subject: Re: [Histonet] unstained paraffin tissue slides storage--why cold? From: Emily Sours <talulahg...@gmail.com> Date: Thu, November 04, 2010 7:07 am To: histonet@lists.utsouthwestern.edu Can I ask what the point of storing paraffin sections in freezing cold storage? They are wax sections, which never see any type of cold, so I don't understand the point of this. I do understand putting them at 4 degrees to prevent mold, but -80 seems excessive. We have kept our slides at room temperature for years and years, but these slides do not have an albumin coat (which I can see getting moldy), just a chemical coating. Fixing for paraffin and paraffin infiltration seems to keep antigens safe without refrigeration because it's so intense, but that's just conjecture on my part. Emily -- Outside of a dog, a book is man's best friend. Inside of a dog it's too dark to read. --Groucho Marx _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet