[Histonet] Weight loss weight gain decalcification endpoint test explanation

[Gayle Callis]

Mark, 

As calcium is ionized and leaves bone collagen matrix, the bone loses
weight.  At the end of this process when calcium is gone, the bone begins
to gain weight again, back to its original weight.  This may be once
calcium is removed, the weight gain is attributed to water now in those
space occupied by calcium. Ones needs to use a balance that weighs in
milligrams for greater accuracy.  

At any rate, the test is quick, saves time and does work.  It was
originally published many years ago as an  nitric acid endpoint test
(pretty harsh, rapid inorganic acid decalcifier).  In the original
publication, and at the end, the decalcifying fluid was chemically endpoint
tested for presence of calcium.  We have never done the latter and if one
does a chemical endpoint test, the decalcifying fluid would have to be
replaced daily near end of decalcification.  You can't leave just multiple
bones in decalcifier for accurate chemical testing - that is better done on
one sample at a time for accuracy and very time consuming when 50 mouse
paws are in the experiment.  

One joy of this method - it works with EDTA decalcification which is
difficult to do chemical endpoint test.  Cathy Mayton has a publication
using EDTA with this endpoint test so it is useful for both acid and
chelation decalcification.   


Gayle Callis
MT,HT,HTL(ASCP)
Research Histopathology Supervisor
Veterinary Molecular Biology 
Montana State University - Bozeman
PO Box 173610
Bozeman MT 59717-3610
406 994-6367 (lab with voice mail)
406 994-4303 (FAX)