This reliable histochemical method for differentiating amyloid AA from AL
was introduced by Wright, JR (1977). The affinity of amyloid AA for congo
red is lost after exposure of tissue sections to potassium permanganate and
dilute sulfuric acid, while leaving the affinity for the dye of AL
unchanged.

Sections are cut at 6 micron, incubated for 3 minutes with equal volumes of
5% aqueous potassium permanganate and 0.3% aqueous sulfuric acid,
decolorized with 5% aqueous oxalic acid, washed twice in DH20 and stained
with alkaline Congo red according to Puchter. Serial sections were stained
with Congo red and served as a control group. With different fixatives and
embedding procedures, the results of the potassium permanganate were the
same. The sections were studied with light microscope and polarizing
microscope. Materials from autopsies were also studied with the fluorescent
microscope. Both methods were comparable with regard to the affinity of
amyloid deposits for Congo red.

Amyloid deposits were considered as potassium-permanganate-sensitive, when
90% or more of the deposits lost their affinity for Congo red after
incubation with potassium permanganate.


Eric C. Kellar
University of Pittsburgh Medical Center

> ----------
> From: 	Ronnie Houston[SMTP:wee_rory@hotmail.com]
> Sent: 	Tuesday, March 21, 2000 10:40 AM
> To: 	histonet@pathology.swmed.edu
> Subject: 	Congo red and potassium permanganate
> 
> Is any one familiar with the technique of Wright JR et al, Lab Invest
> 1977; 
> 36(3):274-281, where they use, I believe, acidified potassium permanganate
> 
> to subclassify amyloid types with Congo red staining?
> I've been asked to do this urgently on a case of Inclusion Body Myositis.
> I've contacted our library to get a copy of the paper but that may take 
> days.
> Can anyone help out?
> Thanks
> Ronnie Houston
> Cytochemistry & Molecular Pathology
> Texas Scottish Rite Hospital for Children
> 2222 Welborn Street
> Dallas, TX 75219
> (214) 559 7744
> (214) 559 7768 -fax
> ______________________________________________________
> Get Your Private, Free Email at http://www.hotmail.com
> 
>