Re: [Histonet] Azure B in giemsa

From:John Kiernan

Yes. Azure B (CI 52010) is the most important component of all traditional blood stains, even if it is not deliberately included in the dyes used to make up the mixture. Giemsa's original recipe (1902) was made from a mixture of thiazine dyes called azure I, which had azure  B as a major component. In a later (1924) formulation, Giemsa used azure II, a mixture containing methylene blue, azure B and other thiazines. When pure azure B became available in the 1970s various investigators, notably P.Marshall and the late D.Wittekind and their colleagues, independently showed that the Romanowsky-Giemsa effects - purple nuclei of leukocytes, red nuclei of malaria parasites etc - required only azure B and could not be obtained with any of the other thiazine dyes included in the various mixtures for staining blood. The anionic dye in a blood stain is nearly always eosin Y. Leishman's (1901) is exceptional in having eosin B instead.

There's plenty of literature in this field. The most recent review that I know is Wittekind's Chapter 21 in the 10th edition of "Conn's Biological Stains" (Oxford: BIOS, 2002, pp 303-312). There's also a very readable article called "Understanding Romanowsky Staining" by Horobin & Walter in Histochemistry 86: 331-336 (1987). The piece on azure B in the late Floyd Green's "Sigma Aldrich Handbook of Stains, Dyes and Indicators" (1990, pp 112-114 is also helpful, and includes discussion of the different available salts of pure azure B, which is made by direct synthesis rather than by degradation of methylene blue.

John A. Kiernan
Department of Anatomy & Cell Biology
The University of Western Ontario
London, Canada N6A 5C1
----- Original Message -----
From: "Martin, Erin" 
Date: Wednesday, August 15, 2007 10:50
Subject: [Histonet] Azure B in giemsa
To: histonet 

> Hi everyone,
> Could someone please tell me if azure B is a component of all 
> giemsa stain?  As far as I can tell, it is in all of them 
> and the variations are in the other steps but I'm not 
> sure.  One of my pathologists would like to know and I want 
> to be sure that I am giving him accurate information.
> Thank you - you all are such a great help!
> Erin
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