LuAnn Anderson <ander093@gold.tc.umn.edu> wrote:
... Has anyone out  there heard of a Thio S for amyloid?  

Looking for the Rudelli ref. suggested by Roger Moretz, nothing showed up
in PubMed (http://www.ncbi.nlm.nih.gov:80/entrez/) but these references
might help if you have access to a medical library:

Westermark GT, Johnson KH, Westermark P Methods Enzymol 1999;309:3-25
Staining methods for identification of amyloid in tissue. 

Kelenyi G Acta Neuropathol (Berl) 1967 Feb 3;7(4):336-48 Thioflavin S
fluorescent and Congo red anisotropic stainings in the histologic
demonstration of amyloid.  

Yamamoto T, Hirano A.  A comparative study of modified Bielschowsky, Bodian
and thioflavin S stains on Alzheimer's neurofibrillary tangles.
Neuropathol Appl Neurobiol. 1986 Jan-Feb;12(1):3-9.

Wisniewski HM, Wen GY, Kim KS.  Comparison of four staining methods on the
detection of neuritic plaques. Acta Neuropathol (Berl). 1989;78(1):22-7.