Histonetters and John,

John K. asked to have the responses to my paraffin question forwarded to
Histonet.  I asked for and received permission to forward the following
responses. Unfortunately, I did not save ALL the responses, so I cannot send
them all. It is most interesting to see different ways in which others are
doing
things.



Hi LuAnn:
We use Surgipath's embedding media and infiltrating media.  They work great
together.  We process routine surgical specimens and have no problem with
infiltration or cutting.  That is if the specimens are fixed well. :)    We
did
try some sample blocks from Richard Allen and they were even better.  They
have
four types of paraffins and will send you a sample of plain block for you to
try.  We tried them and are considering changing to them, that's how good they
are.
I don't know what type of tissue you process, but either of these suppliers
will
have a product for you and give good results.  Hope this helps.


Luann,
This histo lab has been using two types of paraffin. Surgipath- Blue Ribbon
#01350 for tissue embedding and Paraplast Plus HRI 8889-502004. Both are low
temperature; 56-57 degree Centigrade for the Blue Ribbon and Paraplast Plus 56
degree C.. Both have plastic polymers, but the paraplast also contains DMSO
for
rapid tissue infiltration. I recieved sample bags of the blue ribbon and it
gave
better cutting quality. It seems to ribbon better. Our lab handles animal
tissue, eyes, brains, nerves, muscle and skin. We process tissue preserved in
many fixatives; test and pilot studies are run on paraffin infiltrated tissues.
Thank you for your suggestions on getting optimal sections of large N.H.
primate
brains with a minimum of wrinkles. Curious, what lab are you with? sandi miller

LuAnn,
	I use 2 different paraffins an infiltrating paraffin that is softer
and an embedding paraffin that is harder. They are from surgipath. Reason
behind this is that I work with animal tissue, mostly mouse brain and have
found that the softer paraffin infiltrates better[I think], but the harder
embedding paraffin facilitates less compression when cutting. I am sure
there are paraffins out there that would do the same job for both, but at
this time I have neither the time or the inclination to change. If its not
broken don't fix it!!


We use the 52 degrees paraffin from TBS in our VIP, and the oven is
maintained at 58 degrees.
The retort is set at 56 degrees, and we use only the first two paraffin
stations for one hour each.
The results are great from the smallest tissue fragment to the largest.
Depending on the workload we
change the paraffin every 7 to 10 runs. We DO NOT embed with this paraffin,
we use it for infiltration only. The results are great.
>

For processing, the general thought is you need a paraffin with a lower melting
point and not as much polymerization. This will make infiltration easier. For
embedding, you want a paraffin with high polymerization. This makes the tissue
stiffer, thus easier to cut, especially at 2 microns.