Re: [Histonet] cloth yellow stain

From:John Kiernan

Dear Carol,

As Gayle points out, cloth yellow is not in the Lillie's 9th
edition of Conn's Biological Stains (Conn9). Needless to
it's not in Conn10 (2002), from which many obsolete dyes
omitted to make room for fluorescent labels and probes, and
information about old dyes that are still used. 

The three "cloth" dyes in Conn9 are all anionic bis-azo
dyes. The
two blue ones were used, along with many other dyes, in some
many published investigations of staining by Holde Puchtler
her colleagues in the 1960s and early '70s. For the red one
[which is disulphonated sudan IV] Lillie reported no
uses as a biological stain; he suggested that it might serve
as a
"bluish red" cytoplasmic stain. Don't ask! Bluish and
red dyes exist. We should discuss them on Histonet, but not

If the "cloth" moniker was attached to anionic bis-azo dyes,
"cloth yellow" might serve as a yellow background to
with blue, black or red nuclei. There's no shortage of
available dyes for that job. If Chroma's "cloth yellow" was
dye with large hydrophilic anions, it might have served as
collagen colorant in a trichrome-type method, as does
saffron in
Movat's original pentachrome. Such a dye, if available,
might be
much less expensive than saffron. Bryan's advice to ask the
Society of Dyers and Colorists is good. Follow it, and keep 
it up by asking more. 

Chroma had a reputation for selling good stains, but their
labels didn't always commit to the chemical identity by
a Colour Index (CI) number/name or a Chemical Abstracts
(CAS) number, and they did not have samples of their
certified by the Biological Stain Commission.

Bryan Llewellyn would like to keep in touch with your "cloth
yellow" detective work, and so would I. By way of Histonet
we can 
all be informed!
John Kiernan
Anatomy, UWO
London, 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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