That is precisely why we take the cassettes out of the molten paraffin (embedding center) if they cannot be embedded right away. I felt they were being "cooked" as well. We have had not problems sectioning cassettes that have hardened and re-melted.
Peggy Peggy Sherwood Lab Associate, Photopathology Wellman Center for Photomedicine (EDR 214) Massachusetts General Hospital 50 Blossom Street Boston, MA 02114-2696 617-724-4839 (voice mail) 617-726-6983 (lab) 617-726-1206 (fax) msherw...@partners.org -----Original Message----- From: histonet-boun...@lists.utsouthwestern.edu [mailto:histonet-boun...@lists.utsouthwestern.edu] On Behalf Of gayle callis Sent: Thursday, October 06, 2011 12:55 PM To: 'Janice Mahoney'; rjbu...@yahoo.com; 'histo net'; rchar...@pa.gov Subject: RE: [Histonet] Tissue left in processor Some prefer to take the cassettes off the processor and let them harden until embedding can be done, rather than leave in molten, hot paraffin. This does not damage the tissue, and placing the cooled cassettes into the embedding center holding area allows the paraffin to re-melt in a shorter time before embedding. This has been discussed in the past on Histonet. Some tissues may dry out even more WITH difficult sectioning after prolonged heat exposure. One result will be a parched earth effect seen in sections. I see you are from a veterinary facility, and if you work with rodent tissues e.g. spleen and liver, you should not let the tissue sit in paraffin or you will have little hard rocks to section. If your sectioning suffers (dry, friable, shattered, hard) after allowing tissues to sit in hot paraffin as compared to the times when you embed asap after processing is finished, then over exposure to hot paraffin can contributing factor. I personally do not like to "cook" my tissue any longer than necessary and heat labile antigens will also be at risk. I schedule so I can be there to embed when the processing is completed. Our standard is to embed when processing is finished and schedule accordingly. Gayle Callis HTL/HT/MT(ASCP) -----Original Message----- From: histonet-boun...@lists.utsouthwestern.edu [mailto:histonet-boun...@lists.utsouthwestern.edu] On Behalf Of Janice Mahoney Sent: Thursday, October 06, 2011 9:45 AM To: rjbu...@yahoo.com; histo net; rchar...@pa.gov Subject: RE: [Histonet] Tissue left in processor I agree with Rene, as long as the temp is only a few degrees above the melting point of the paraffin.Jan,Omaha > Date: Thu, 6 Oct 2011 07:13:54 -0700 > From: rjbu...@yahoo.com > To: histonet@lists.utsouthwestern.edu; rchar...@pa.gov > Subject: Re: [Histonet] Tissue left in processor > CC: > > I do not think that a well fixed, well processed tissue left in molten paraffin for 2 hours after the processor finished will have any adverse outcome. > René J. > > --- On Thu, 10/6/11, Charles, Roger <rchar...@pa.gov> wrote: > > > From: Charles, Roger <rchar...@pa.gov> > Subject: [Histonet] Tissue left in processor > To: "Histonet (histonet@lists.utsouthwestern.edu)" > <histonet@lists.utsouthwestern.edu> > Date: Thursday, October 6, 2011, 10:05 AM > > > Hi All, > Is there any standard on how long tissue cassettes can remain in the processor after processing before the tissue is subjected to unwanted outcomes? And if so what type of artifacts can one expect from tissue that was in the processor in molten paraffin for 2 hours after the processing was completed? > Thanks so much. > Roger > > Roger Charles| Microbiologist II > Pennsylvania Veterinary Laboratory > 2305 North Cameron Street | Harrisburg, PA 17110 > Phone: 717.787.8808 | Fax: 717.772.3895 > www.agriculture.state.pa.us<http://www.agriculture.state.pa.us> _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail. _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet