[Histonet] RE: best controls (Bob Richmond)
TNMayer <@t> mdanderson.org
Mon Jun 11 13:49:34 CDT 2012
For trichrome: appendix is the most universal control I know of. Then maybe a kidney.
GMS: store bought controls are nice, but if you live close to the local morgue try them, every so often they get a good case that they can spare some.
Hemosiderin: Fetal Liver is good, or as you say dog. Call the vet or vet school and see if they can get you some. Also ask them for some mast cell tissue. Dogs get mast cells and they stain beautifully.
Amyloid: the problem is with the storage, just freeze the block after you cut it. One block should last you for years. Also contact the closest amyloidosis clinic and see if they can find a place to supply a block. They would know of positive cases.
AFB/Fite: get in touch with Hansen's disease center, they can provide you with a block 'free' of charge.
Date: Sat, 9 Jun 2012 22:47:22 -0400
From: Bob Richmond <rsrichmond <@t> gmail.com>
Subject: [Histonet] Re: best controls
To: histonet <@t> lists.utsouthwestern.edu
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What controls for trichrome, methenamine silver fungal stain, and hemosiderin?
For trichrome, whatever keeps the regulatory agencies happy.
Pathologists use it mostly for liver biopsies, so an autopsy liver with early hepatic fibrosis would be ideal. But I don't bother to look at the control.
GMS methenamine silver for fungi: I'd want histoplasma growing in human tissue, with numerous yeast forms with a history of bad staining. But you take what you can get. A Candida culture injected into a mouse lung is what I expect to see.
Hemosiderin: any tissue with hemosiderin in it. Dog spleen or liver works quite well - unlike people, dogs store a lot of iron. Human hemochromatotic tissue is hard to get, and I'd hope increasingly difficult.
Could I add amyloid? The only control I can usually get is human medullary thyroid carcinoma. Amyloidosis is easily induced in experimental animals, and I've asked on Histonet several times - why isn't this tissue available for clinical use?
And acid-fast? Once again, I expect mouse lung injected with AFB. The best I've ever seen was rhesus monkey lung, those pestiferous New Delhi monkeys come to autopsy. Leprosy requires a separate AFB control. Once again, why not animal material. Leprosy is easily produced in armadillos (Dasypus novemcinctus), and one lepradillo could supply the world for a century.
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