RE: Subject: [Histonet] Zinc formalin on human renal biopsies

From:"Johnson, Teri"

Steven,

I was wondering that too. Although the tissues had been stored in 70%
alcohol, I had post-fixed one sample another 4 hours in Zinc Formalin.
I ran the post-fixed tissues in the processor at the same time as the
originally Zinc Formalin fixed material, and the morphology was worse
with the post-fixed sample.  Again, this was a sub-optimal test in that
it would be more helpful to use fresh pancreas for the fixation test,
but it's the material that I had available.

Having used Zinc Formalin extensively on human lymph node specimens in
the past, I've seen what prolonged fixation (overnight) in Zinc Formalin
can do to harden them.  Maybe the formulation is the key here, as Gayle
has used Anatech's formulation for 15 hours with tiny kidney biopsies
with no ill effects.

Thanks for your input!

Teri

-----Original Message-----
From: Steven E. Slap [mailto:siksik03@comcast.net] 
Sent: Wednesday, April 28, 2004 10:16 AM
To: Johnson, Teri
Cc: HistoNet Server
Subject: Subject: [Histonet] Zinc formalin on human renal biopsies


Hi Teri & HistoNetters

Given that you only fixed the pancreas for three hours in the Zinc 
Formalin, I wonder whether your problem isn't just underfixation, as 
opposed to the overnight fixation in formalin.  The dryness and 
brittleness could be due to exposure to alcohols before the tissue 
was properly fixed.

Just a thought...

Steven Slap

>At 01:15 PM 4/27/2004 -0500, you wrote:
>  >In working through our processing schedule dilemma, we fixed some
>>pancreas in NBF (overnight), and fixed some in Zinc Formalin for 3 
>>hours, followed by water wash and storage in 70% ethanol.  We found 
>>that using a variety of processing schedules, the NBF fixed pancreas 
>>looked good with routine 30 min/station (with 2 hours total time in 
>>paraffin), all the way down to 10 min/station (with 80 min total time 
>>in paraffin). The Zinc Formalin fixed pancreas looks dry and brittle 
>>still, even with the short processing schedule.
>>
>>It was amazing to see how firm and grayish the tissue was as compared 
>>to the NBF fixed tissue, within even an hour of fixation time.
>>
>>We will try a hand-processing schedule for these to see if we can get 
>>the processing perfect for the ZnF pancreas.  Our answer to this 
>>problem could be that we need to limit the amount of time it is in 
>>fixative. Gayle, how long were the kidney biopsies fixed before 
>>processing?
>>
>

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