On Mon, 16 Oct 2000, Ryan.Linda wrote:

> I'm searching for Astra Blue(CI#34195).  The manufacturer has
> discontinued production. Anybody have this dye in your lab?  Where did
> you get it?

 The name astra blue has been applied to various dyes used in histology,
 and there has always been doubt about their identities (see Conn's
 Biol. Stains 9th edn, 1977, p.455). Some have been used in the same
 way as alcian blue. The Colour Index (CD-ROM version, 1996) does not
 have an entry for 34195. It contains two astra blues: Astra blue G
 is Basic blue 56, which is a triarylmethane dye (perhaps similar to 
 a victoria blue); Astra blue 6GLL is Solvent blue 51, whose chemical
 class is not stated. (Solvent blue 52 is a phthalocyanine, therefore
 perhaps similar to luxol fast blue MBS. Some luxol dyes are azo
 dyes, so this doesn't tell us what SB52 might be). Both the astra 
 blues are manufactured by Bayer AG, and neither has a CI constitution
 number, so we have no idea what these dyes are. They therefore
 should not be used in scientific work.

 If you are after a substitute for alcian blue I would recommend a 
 recent article by C. Churukian, M. Frank and R. W. Horobin  in
 Biotechnic & Histochemistry 75 (3): 147-150 (May 2000). The authors
 report testing of alcian blue pyridine variant (sold by Aldrich)
 and compare it with several samples of alcian blue. The conclusion 
 is that alcian blue pyridine variant is the superior dye because
 it is more stable (over a 10-year period) than some batches of 
 alcian blue. This paper also explains the chemistry of the dyes
 and discusses factors contributing to their long-term stability.

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1
   Phone: (519) 661-2111
   FAX (Department): (519) 661-3936
   E-mail: kiernan@uwo.ca