I believe amyloid does fade with age on cut slides. Frieda sited Bancroft and Cook that intensity decreases with age and "long-standing" deposits stain less intensely than smaller "Newly formed" deposits. She also lists a Crystal Violet method in the 3rd edition, but that it is more of a rapid screening technique and is not as specific as Congo Red. Claire
________________________________________ From: histonet-boun...@lists.utsouthwestern.edu [histonet-boun...@lists.utsouthwestern.edu] on behalf of Wheelock, Timothy R. [twheel...@mclean.harvard.edu] Sent: Friday, January 23, 2015 2:00 PM To: 'histonet@lists.utsouthwestern.edu' Subject: [Histonet] Paraffin-Plastic Stratification/Congo red problem Hi Jeffery: Yes, I notice the same "paraffin dust bunnies", perhaps especially since I use a embedding paraffin that has a fair amount of plastic. Before I embed my brain tissue, I mix the embedding media thoroughly, until the solution is clear. As for your Congo Red problem, I wish that I could help you. I am now experiencing the same problem, except that it affects the positive controls as well. The staining is there, but much fainter than it should be. I usually immerse albumin coated slides in 1% Congo red for 15 minutes, differentiate them with Potassium Hydroxide for 3 dips, counterstain with Harris Hematoxylin for 1 minute, differentiate with acid alcohol for 5-10 dips, immerse in running tap water for 10 minutes, immerse in 95% ethanol for 2 dips, then dehydrate and mount. Tim 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 _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet
