RE: Fontana-Masson staining on appendix

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From:Hewlett Bryan <HEWLETT@HHSC.CA>
To:"\"\" " <>, "'CHEN, YUETIAN'" <>


The Masson-Fontana Argentaffin technique, when used on appendix, is for the
demonstration of granules in specialized enterochromaffin cells which
contain the biogenic amine 5-Hydroxytryptamine(5-HT).
Rosalind is quite correct. If alcohol is used as a fixative the argentaffin
granules disappear. Interestingly however, the cells retain their Argyrophil

Fixation in formaldehyde(other aldehydes also work) is NECESSARY for the
argentaffin reaction to occur with 5-HT. Treatment of 5-HT with aldehydes
causes a condensation reaction with the production of
3,4-dihydro-B-carboline. These compounds fluoresce and form the basis of the
formaldehyde-induced fluorescence characteristics of amines and precursors.
The B-carbolines are also reducing substances and have the capability to
directly reduce silver solutions, that is, they are Argentaffin. Most
B-carbolines are relatively insoluble in the reagents used for tissue
processing. Therefore paraffin sections can be used.

The Samurai's comments about poor fixation are well founded, although I
would have to point out that the method does indeed work well on
formaldehyde fixed frozen sections. It also works on fresh frozen sections
if they are fixed in formaldehyde prior to performing the technique.


> ----------
> From: 	CHEN, YUETIAN[]
> Sent: 	August 16, 2000 2:20 PM
> To: 	"" 
> Subject: 	Fontana-Masson staining on appendix
> Dear histonetters:
> I am taking htl exam and on of the special staining is Fontana-Masson
> staining 
> on appendix.  According to Carson's book, alcohol should be avoided
> because 
> alcohol dissolves argentaffin granules. Does that mean I need to do the
> staining
> on frozen section?  Actually, in the procedure, it indicates the staining
> can be
> done on paraffin section because first step is deparaffinize.  After
> stianing, 
> the section can be dehydrate and clear with alcohol.  I am confused.
> Should
> I 
> use frozen tissues for my exam and totally avoid alcohol from begining to
> the 
> end of the staining?  Since finding the tissue is not easy for me, I need
> to
> make sure I am doing it right.  Would you be able to give me some
> suggestions?  
> Thank you very much.
> Yuetian

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