[Histonet] Apple Green Birefringence in Amyliod slides

[Bruce Schainker]

I would add three additional pointers:
1) Assess in a darkened room with eyes acclimated to the dark;
2) Use a powerful light source--the apple green birefringence will be more
obvious and easier to discriminate from the white of collegen; and
3) Assessment sensitivity is further increased if instead of using the
inexpensive films that Tim describes you use a more traditional polarizing
microscope or a regular light microscope with an polarized lens above the
objectives (my microscope has a slide-in slot) and another above the field
lens (I use a removable circular polarizer that fits over the entire field
lens).
Bruce

On Tue, Jul 28, 2020 at 3:06 PM Morken, Timothy via Histonet <
histonet at lists.utsouthwestern.edu> wrote:

> I neglected to mention sections should be cut at 10um for best results.
>
> Tim Morken
> Supervisor, Electron Microscopy/Neuromuscular Special Studies
> Department of Pathology
> UC San Francisco Medical Center
>
>
> -----Original Message-----
> From: Morken, Timothy via Histonet <histonet at lists.utsouthwestern.edu>
> Sent: Tuesday, July 28, 2020 11:57 AM
> To: Ken M <kdean70 at hotmail.com>
> Cc: Histonet <histonet at lists.utsouthwestern.edu>
> Subject: Re: [Histonet] Apple Green Birefringence in Amyliod slides
>
> Ken, Yes, polarized light and apple green birefringence is diagnostic for
> amyloid with congo red and is the best practice. If you have a problem with
> known control slides  there are two possibilities: 1) make up fresh
> solution. The pH has to be right. Or 2) try other control slides. Maybe you
> cut through the amyloid area.
>
> Because we have hundreds of microscopes in our department most just use
> polarized film as the polarizer (put over the light source) and another put
> over the top of the slide as the analyzer. Turn one of the polarizing
> slides and you will see the birefringence appear.
>
> Source:
> "Polarizing film, 2"" x 2"" , PK/10 (BEST For use as a microscope
> polarizer)"   Cat# S07372     Thermo Fisher Sci Health        $36.75
> PK/10   "2" x 2"
>
> These are polarized film mounted in 2" film holders (like the old
> Kodachrome slides).
>
> Cheap and effective. (and avoids consternation from people losing
> expensive microscope polarizers)
>
> Tim Morken
> Supervisor, Electron Microscopy/Neuromuscular Special Studies Department
> of Pathology UC San Francisco Medical Center
>
>
> -----Original Message-----
> From: Ken M via Histonet <histonet at lists.utsouthwestern.edu>
> Sent: Tuesday, July 28, 2020 11:43 AM
> To: histonet at lists.utsouthwestern.edu
> Subject: [Histonet] Apple Green Birefringence in Amyliod slides
>
> Hi everyone.  I was wondering if anyone out there has any experience with
> diagnosing Amyloid tissue using Congo Red stained Kidney using polarized
> lenses.  Is it common to use polarized light to detect Amyloid deposits?
> Does the absence of the "apple green birefringence" indicate a problem with
> the control tissue or the control slides?  Should this green bifringence
> always appear to confirm the diagnosis?  I know that the tissue should be
> cut thicker than normal (we usually cut at 5), but in the future maybe we
> will cut at 7 or 8?
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