[Histonet] cloth yellow stain

[Paul Bradbury]

For the last couple of hours I have been racking my brain to try to 
recall where I have come across this dye before.
But, the required neurons are not responding ... or only weakly.

John Kiernan is right on target ( as usual) in suggesting that this dye 
is almost certainly a large molecule azo dye (actually a very long, 
linear molecule) anionic dye probably used in the textile industry for 
coloring cotton fibres. If I remember correctly, such dyes are often 
referred to as "milling dyes". Similar azo dyes are commonly used for 
dying natural fibres in industry. In histology, dyes of this type are 
used to show amyloid (Congo red being the classical example).

Yellow dyes provide poor visibility to tissue elements, so this dyes is 
almost certainly a counterstain used to highlight general background 
structures and to contrast with a red or blue primary stain. My 
suggestion would be to make up a 0.5% solution of the dye in 1% acetic 
acid, and try it out on a few sections of tissue.

Let us know what the results are ... I am sure we would all love to know 
for sure..

Paul Bradbury
Kamloops, BC
Canada



McCollough, Carol wrote:

>Greetings Histonetters:
>
>In an exhaustive inventory of laboratory chemicals we have discovered an old bottle of 'Cloth Yellow' stain powder, manufactured by Chroma.  Efforts to get an MSDS from Chroma have failed.  Nobody here knows what this was even used for.
>
>Would anyone care to offer any histological uses for this stain?
>
>Regards -
>Carol
>**********************
>Carol B. McCollough
>Aquatic Animal Research Pathologist
>Oyster Disease Research Project
>Fisheries Service
>Maryland Department of Natural Resources
>Cooperative Oxford Laboratory
>904 S. Morris Street
>Oxford, Maryland 21654
>410-226-5193 x124
>
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