[Histonet] Bouin's, formic acid & and sirius red staining

[Tyrone Genade]

Hello,

Some questions regarding Bouin's solution.

I was told, back when I was doing my PhD and new very little, that I should
fix my fish in Bouin's as it will decalsify the bones. Well, Bouin's fixed
fish were easier to cut than PFA fixed fish... but I read today that by
adding formic acid the decalsification is better. (I must confess, that
after Buoin's fixation I still had to soak the tissue face in some dilute
nitric acid now and then...) Another reference said that the formaldehyde
should be replaced with formic acid. So which is it: add formic acid or
replace formaldehyde? And if the former, how much do you add?

Second question: a colleague and I want to stain for collagen in diseased
kidneys. The fixative of choice for soft tissue is Bouin's... But the
staining protocol called for a solution of picric acid and sirius red. Is
the picric acid needed if I haven't washed the picric acid from the Bouin's
fixation out of the tissue? I was told once that the picric acid was for
contrast... Is this BS? Does the picric acid play an important chemical
role in the staining? I would like to avoid the need for a bottle of
saturated picric acid on the lab shelf here in Iowa where the winter low
humidity desiccates everything... I'm hoping this protocol,
http://www.ihcworld.com/_protocols/special_stains/sirius_red.htm , can be
modified to omit the picric acid.

Thanks
-- 
Tyrone Genade
Orange City, Iowa
tel: (+1) 712 230 4101
http://tgenade.freeshell.org
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