RE: embryo/age/calcification

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From:"Saby, Joseph" <> (by way of histonet)
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I have worked with eighteen day gestation and neonatal mice.  There is
calcium, but in my experience, it was very little.  The mice were fixed in
10% NBF after their abdomens were opened.

I did not process them whole.  First I removed the head and sliced it into
four cross sections.  Then I bisected the carcass with an off-center slice
so the spinal column would stay with one section.  If the section with
spinal column was too thick for the unicassette, I trimmed as needed and
placed the outer section in another cassette.  I then decalcified the
sections with bone overnight in a formic acid-sodium format decalcifying

I believe I processed these cassettes on our standard rat program.  At
embedding, the first section of skull was oriented caudal surface down and
the rest rostral surface down.  The body sections were placed largest
surface down in the cassette, and held down to keep everything as flat as
possible in the mold.

I then step sectioned all the blocks.  I arranged the slides for the skull
from the tip of the nares to the cervical region.  The body slides were
arranged from one side to the other.  At the point where two body blocks
met, when facing I went in to first tissue, then went in 1/2 the normal step
section before collecting a slide.  Some of these sections were not quite
complete, but the spacing between sections was maintained.

My results were excellent, with no decalcifying artifact on the delicate
tissues, and all sections were well processed.  There was still a little
residual calcium in the long bones, but not enough to compromise the
sections. If you have any further questions, please contact me.


Joseph A. Saby, BA HT(ASCP)
Diagnostic Pathology, Pathology & Experimental Toxicology
Parke-Davis/Int. Pharm. Res. Div. Warner-Lambert
Ann Arbor, MI 48105
Phone: (734) 622-3631
Fax:     (734) 622-5718

-----Original Message-----
From: Gayle Callis []
Sent: Monday, November 08, 1999 7:03 PM
Subject: embryo/age/calcification

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

Gayle Callis

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