Date sent:      	Mon, 8 Nov 1999 17:02:54 -0700
From:           	Gayle Callis <uvsgc@msu.oscs.montana.edu>
Subject:        	embryo/age/calcification
To:             	histonet@pathology.swmed.edu

A whole new era in my lab.  How much calcification is  present
in a 3 day old mouse?  also a newborn mouse?  Our transgenic mouse
expert has specimens sitting in formalin, collected, frozen, allowed to
fix in formalin while thawing.  We would like to process the
whole mouse in all instances, and wondered how much decalcification
would be necessary, if needed at all, preferrably with 10% formic
acid.

Gayle,
quite a bit, especially the limbs.We routinely decal mice from
18days (dpc) when sufficient amounts of calcium is present to
affect good sectioning.EDTA for a few days at 37oC is usually
adequate up to newborn then increase as they get older.For 3 day
we would give 5 days in EDTA then process over the weekend
(2 days in 10% formic should do just as well).The critical part is as
I am sure you are aware is thorough fixation, especially if you are
intending to process whole. I would recommend at least removing
the skin and opening the abdomen.