John -

I remember a Journal of Histotechnology article about
10 years ago, about using CEV (CVA) for staining
pneumocystis.

It stained not only the cyst, but also the
trophozoites (advantage over the GMS, which does not
demonstrate the trophozoites).

pH was important if I remember, but I don't remember
what the pH was.

I do remember it was written by Christina Genaw,
who was at that time at Heritage Hospital. She's
another Michigander, which is why I remember the
article.

Peggy A. Wenk, HTL(ASCP)
William Beaumont Hospital
Royal Oak, MI 48073

"J. A. Kiernan" wrote:
>
> On Fri, 28 Apr 2000, L. Gibbs wrote:
>
> > Sorry, I am not familiar with using Cresyl Violet for feulgen
> > staining. I use the above Cresyl for Nissl staining.
>
>   I'm pretty sure that Nissl staining is the only job that
>   cresyl violet is used for. It's a cationic (basic) dye, and
>   it stains both nucleic acids; also sulphated compounds like
>   those in cartilage and mast cells, if present in the section.
>   It is one of the dyes certified by the Biological Stain
>   Commission, and is sold by larger American vendors (and smaller
>   ones too, I'm sure) under the name of cresyl violet acetate.
>   It does not have a C.I. number (never having been a commercial
>   colorant - the neurobiological market alone just isn't big enough
>   to be noticed by the Society of Dyers and Colorists).
>
>   The Feulgen method is quite different: acid hydrolysis removes
>   RNA and degrades DNA to a polyaldehyde that is then stained with
>   Schiff's reagent. There are Schiff-like reagents that can be made
>   by adding thionyl chloride (source of SO2) to aqueous solutions
>   of dyes other than basic fuchsine. Possibly cresyl violet is
>   one such dye, but this would be a very unusual, obscure technique.
>   The only pseudo-Schiff reagent that's seen much use is the one
>   derived from thionine, which is used in some of the fancy PAS-type
>   methods for sialoglycoproteins. Fluorescent pseudo-Schiff reagents
>   can also be made. The one from acriflavine and SO2 is quite
>   dazzling in PAS-type staining. The pink to red product seen in
>   sections stained by the regular PAS or Feulgen mathod (using
>   ordinary Schiff from basic fuchsine) also fluoresces in a quite
>   pleasing but not brilliant orange-brown - a fact rarely remarked
>   on in modern books and papers.
>
>  John A. Kiernan,
>  Department of Anatomy & Cell Biology,
>  The University of Western Ontario,
>  LONDON,  Canada  N6A 5C1