[Histonet] Oddball formalin question!
dobbin <@t> upei.ca
Tue Jun 1 11:54:59 CDT 2004
Here is this weeks oddball question! I am tring to make latex casts
of air sacs in birds (the veterinary people will know that birds have
air sacs and pneumatic bones that work in conjuction with the lungs
to facilitate O2 uptake [among other functions such as temp. reg.]).
First of all, we will gently compress the birds body (these birds are
found dead and brought in by the public-we are not euthanizing!) to
force out excess air. Then, while suspending the bird by the head
we will run liquid latex into the trachea. We hope to make casts of
the communications between the lungs and the various air sacs
and subcutaneous air pockets. Some these diverticuli are quite
small so we think we will have to dilute the latex to make it thin
enough to pass thru these tiny openings.
So since we are diluting the latex anyway, why not dilute it with
formalin (10% NBFS) so that we simultaneously begin to fix the
surrounding structures? However, diluting the latex means that, by
default, the formalin is also being diluted. My question then is this:
"What would happen if I made the formalin up partly with latex so
that the final concentration of formalin in my latex-formalin mixture,
would be 10% and the latex concentration would still be high
enough to effectively polymerize?"
(I have already tried diluting latex with water and it still polymerized
at a dilution of 1:4 following 18 hours at -20 C [checked after
thawing of course]).
I'm thinking the osmotic pressures would be out of whack and the
formalin probably won't penetrate very far from the latex cast
anyway, but I thought some you with better knowledge of formalin
fixation could offer some insight or suggestions before I start
playing around with this.
I can't wait see the replies on this one!!
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