Re: MSB Trichrome stain.
|From:||Bryan Llewellyn <firstname.lastname@example.org>|
From: "J. A. Kiernan" <email@example.com>
> Lillie did experiments of this kind, and was
> not impressed with the notion of PMA and PTA as "colourless acid dyes"
> promoted by J.R.Baker. I think most other investigators would
> disagree with Lillie on this one.
> PTA (or PMA) attaches to collagen and displaces medium-size dye
> anions (usually red) from it, but doesn't do the same for
> cells (except for certain secretory granules). For reasons that
> aren't glaringly obvious, PTA allows the largest dye anions of
> the trichrome mixture (usually aniline blue or fast green FCF)
> to bind fairly selectively to collagen.
I have always preferred Baker's explanation for this.
There is often an assumption that the tungsten or molybdenum is the culprit,
although I note you did not say that. In one of his numerous Picro-Mallory
stains for fibrin (IV, I think) Lendrum used a solution of trichloroacetic
acid instead of PTA. Results were perfectly satisfactory as I recall.
I have always assumed from that method that a relatively large molecular
weight acid solution is all that is required. In fact I remember reading
somewhere, sometime that any acid would do including acetic, citric etc,
although I have never checked it out.
Do you have any comments on this, John?
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