re more questions

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From:BB racing <>
To:Adrienne Vair <>
Content-Type:text/plain; charset="ISO-8859-1"; X-MAPIextension=".TXT"

Hello again
1. What is the maximum amount of time one can fix in BB's fixative?.  This fixative was
designed as a very rapid fixative for biopsies and other small specimens, which would be
processed within 24-48 hours. However we have gone back and taken retrim blocks from
specimens fixed in this reagent several weeks later with no apparent loss of morphology.
However, I would suspect that after several months, the acetic acid in the fixative would
eventually start to degrade the nuclear DNA. Formalin fixed tissues that have been stored
for long periods of time suffer from this problem due to the formation of formic acid, and
unless marble chips are added to the storage container to neutralize the formic acid, they
look pretty bad after a few years, so I would expect the same would happen with BB's
2.  Does BB's fixative affect estrogen receptor proteins?  This is a problem that someone
needs to work on, as it has been my experience that breast biopsies that are processed
before they are adequately fixed in formalin give spurious estrogen receptor results.  The
problem seams to center around the fact that these proteins are some what soluble in
alcohol, and therefor can be extracted from the specimen during the dehydration stage
during processing.  To make matters worse, this seams to vary from patient to patient, with
some being very sensitive, and others less so.  BB's fixative is an alcohol based fixative,
and gave very spurious results when estrogen receptors were attempted on tissues fixed
in it.  We therefor established a policy at the KGH that breast tissues that were to have
ER's done on them were to be trimmed, placed into tissue cassettes, and placed in
formalin for 24 hours before processing.  This has alleviated the problem to a large
degree, but we still have specimens that show inconsistent results.
3.  How many cassettes do we process and how often are the solutions changed?  There
are days when the processors are jammed to the brink, but most days two full racks with a
few lose cassettes.  We change the solutions weekly, but only the first bottle, by dumping
it and moving the others ahead, replacing the empty space with fresh reagent, this goes
for the xylene as well as the wax.  Occasionally if the unit has been worked exceptionally
hard we will change the first two bottles of alcohol/xylene.
4.  What model of VIP do we have?  Can't help you there as I retired before it arrived, that
is why I'm not that familiar with its workings.
Kerry Beebe ART

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