[Histonet] RE: Thioflavine S for Amyloid

[Houston, Ronald]

Jean,

obvious disadvantage is you need a fluorescence microscope, but then you need polarizing filters for Congo red (not as expensive though!)



I haven't used Thioflavine S but Thioflavine T. My understanding is that Thioflavine S, which is a chemically different dye, tends to fluoresce strongly but nonselectively, and can overstain the whole section. Either way, the staining is not light-fast!



Sections need to be kept in the dark until examined and usually within no more than a couple of days.



I used it a lot back home where it seemed to be preferred more than Congo red. It is a very simple stain to perform, and obviously can be screened quickly. Dissolving the dye in 0.1M HCl gives greater selectivity. The dye soluton has a shelf-life of a month or more if kept in the dark.



It is important to counterstain the sections with Mayer's hematoxylin as this quenches any nuclear fluorescence.



Elastic fibers, fibrinoid, mast cell granules and Paneth cell granules fluoresce with this method but they can be easily identified as such and ignored



The method of Burns et al gives probably the most consistent results: Burns J, Pennock CA, Stoward PJ. The specificity of staining of amyloid deposits with Thioflavine T. J Pathol Bacteriol 1967; 94: 337-344



Intersting comments  in Puchtler's paper: Puchtler H, Sweat Waldrop F, Meloan S. Application of thiazole dyes to amyloid under conditions of direct  cotton dyeing: correlation of histochemical and chemical data.  Histochemistry 1983; 77: 431-445





Ronnie


Ronnie Houston, MS HT(ASCP)QIHC
Anatomic Pathology Manager
ChildLab, a Division of Nationwide Children's Hospital
www.childlab.com

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-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Mitchell Jean A
Sent: Friday, April 12, 2013 2:21 PM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] Thioflavine S for Amyloid



Would appreciated some feedback/input from labs using Thioflavine S staining protocol for amyloid screening.  Any advantages/disadvantages to this procedure vs Congo Red?



Thanks much!!



Jean Mitchell, BS HT (ASCP)

University of Wisconsin Hospital & Clinics Neuromuscular Laboratory

600 Highland Avenue

Madison, WI  53792-5132







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