[Histonet] Re: Histonet Digest, Vol 39, Issue 35
John PJ Coleman
jcolclefa <@t> aol.com
Fri Feb 23 18:45:27 CST 2007
1) Nail Fungus: In our lab we use PAS with a light green
counterstain. We soften them in "Nair" first. 10 min 1% periodic
acid, rinse DIH2O, 20 min schiff reagent, Develop in warm standing
tap water, 2% Alc Lt green solution 2-3 min, run down , cover.
Charged slides so they don't wash off.
2) ER/PR- our docs get nervous if the control isn't at least 50%
strongly pos. The best option is a mixed block with multiple cases of
varying expression. Embed 6 slivers from 6 separate cases, document
your "reactivity map" include liver or tonsil which should always be
negative, and voila! multiple ranges and neg tissue control on one
3) Microwave venting: Our microwave processors are vented to outside.
If the stains you use in the microwave include AFB (Carbol
fuchsin=phenolic) PAS (schiff= sulfite) or GMS (methenamine) then you
may have to at least use them under a hood.
4) IHC/DAB- I've coverslipped DAB IHC's after drying well with no
ill effect, no alcohol or xylene.
5) Cheese brains- If your primary freeze produces no artefact,
(cheese holes) then holding at a colder temp after adding OCT will
not create them. Your sucrose treatment already prevents big ice
crystals from forming in the brain/producing cheese holes when you
freeze in the cryostat. (Wood frogs, Rana sylvatica, hibernate
completely frozen using this method, defrost in the spring and walk
away with no cheesy brain holes) The faster the freeze, the smaller
the crystal. We freeze in isopentane cooled with LN2, then add OCT,
then store @ -70 and get no freeze cheese.
6) Recycler- Anatech sells buffer packs for recycled formalin, and
FDA doesn't certify alcohol, xylene or formalin, but may restrict the
use of such in FDA approved procedures, such as Herceptest or
PathVysion, etc. Check the package inserts for your FDA approved
tests to see if recycled stuff is allowed or not. PS- recycling
formalin= bad idea. The theory doesn't make sense to me. It isn't a
solvent, formaldeyhde molecules are lost in fixation to the tissue,
is't more pain than it's worth. I liken it to distilling urine to
save on distilled water costs. I'd much rather spend that time on
making my hematoxylin. Now THAT's fun!
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