barbara.bublava <@t> meduniwien.ac.at
Thu Jun 22 11:20:22 CDT 2006
Dear Robert, Dear Gayle
trying to keep my Message short, maybee I ended up beeing too short
I did not want to test if tissue can be fixed in 70% Ethanol. I did want
to show what happens if tissue isn´t fixed enough (Dorothy mentioned
expired formalin) and wents to the processor - often starting with 70%
alcohol - or transferred, as Robert mentioned, to it for longterm storage.
I tested the "extremes"!
1.) no fixation (70% alcohol, trying to simulate starting the processor
with unfixed specimen)
2.) "half" or partial fixation (transferred to 70% before fixed
completely - which means a rather big specimen for 4 hours, fixed at the
edges, not in the center) - trying to simulate staring the processor
with partial fixed specimen. The case one doctor "produced" by insisting
on fast processing
3.) and "proper" fixation. (24 hrs - for a middle sized specimen, fixed
in the center also) - correct procedure
I did this short test to demonstrate how the incosistant staining the
doctor claimed did happen and to show how important fixation is for a
correct staining (nothing really new to us, but some doctors...)
I did choose Chloracetate Esterase Kit because it was the stain burdend,
HE also did show differences but after all it could be interpreted.
CAE did fail comletely!
I don´t know if this is the solution for Dorothy´s problem, since I did
my little test on human tissue and do not know if the stain will work on
rodent, like other people considered.
If alcohol and not autolysis is the problem - then it could maybe help
to move the specimens to fresh formalin before processing?
I know there are impairments in my little demonstration - for example
the time specimens were left in 70% Ethanol (before moving to the
processor) differs from 0 to 24 hrs (I wanted to process, cut and stain
them together - so there can be no differences)
a lot more testing could be done, and I would do it if I had the time
but at least and for my intention the test did what it should do. The
doctor understood the overhelming importance of correct fixation.
Medical University of Vienna
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