[Histonet] Fontana Masson Staining

[Randy Khoo]

Dear All,

I hope someone can help me out here. I read that
alcohol will dissolve the argentaffin granules. How
does the chemistry work here? Is it only because of
beta-carboline formation or are there other reactions
taking place as well? Is the disappearance of
argentaffin granules under alcohol fixation
confirmatory of its presence if compared to a parallel
formaldehyde staining showing its presence?

Also, if I use alcohol fixation, the cells tend to
shrink and shrivel. Is there any way I can preserve
the morphology with alcohol fixation (ie any other
components I can add to alcohol)?

Does Fontana-Masson staining pick up oxidized melanin?
I presume its ability to reduce silver ions is because
in the natural state, melanin is mostly in the reduced
form.

Therefore, is it possible that FM is not picking up
all the melanin in a cell? However, am I right in
assuming that formalin as a strong reducing agent
would reduce all the melanin in melancytes if they are
fixed in formalin?

Thanks in advance.

Randy






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