[Histonet] Re: Embedding Media

[Rene J Buesa]

In spite of many opinions on the contrary, I always found an error to use two different paraffins: = one for INFILTRATION and the other for EMBEDDING.
You have to consider that, theoretical this is a mistake, because the paraffin that has infiltrated the tissue and REMAINS inside it sustaining its microscopic architecture should be the same, with the same resistance to cutting, than the embedding paraffin.
The thing is that you have to select a paraffin adequate for your subjects. When many years ago I used to work with plant material I always used a high melting point paraffin (63-65ºC from Merck), a lower melting point (53-57ºC) for adult animal tissue, and a softer paraffin (45-50ºC) for embryonic material.
Having a tissue infiltrated with a paraffin with a certain melting point (resistance) surrounded by ANOTHER paraffin with a different melting point (either higher or lower, but usually higher) is a mistake.
Select a paraffin adequate for your subject and use it for both the infiltration and the embedding.
René J.

--- On Mon, 7/11/11, amitapandey <@t> torrentpharma.com <amitapandey <@t> torrentpharma.com> wrote:


From: amitapandey <@t> torrentpharma.com <amitapandey <@t> torrentpharma.com>
Subject: Re: [Histonet] Re: Embedding Media
To: "Tim Higgins" <thiggins <@t> cddmedical.com>
Cc: histonet <@t> lists.utsouthwestern.edu, histonet-bounces <@t> lists.utsouthwestern.edu
Date: Monday, July 11, 2011, 2:07 AM


I continuation of same discussion , i would like to have clarification for 
our lab..we use ....beaded paraffin "Leica Paraplast"  both for processing 
and embedding . Do you advice us to use different paraffin for both steps?


Paula, Please share if you get any feed back on Richard Allan product.

Amita


From:   "Tim Higgins" <thiggins <@t> cddmedical.com>
To:     <histonet <@t> lists.utsouthwestern.edu>
Date:   07/08/2011 11:34 PM
Subject:        [Histonet] Re: Embedding Media
Sent by:        histonet-bounces <@t> lists.utsouthwestern.edu



Hi Paula,

Obviously there are no "compression free" paraffin's on the market.  Look
for a paraffin with a higher polymer content, this makes the paraffin 
firmer
and less likely to compress.  Other factor for into section compression 
but
paraffin is a good place to start.

The higher polymer paraffin's are not as suited for processing, it is more
for the embedding portion of the process.

Use a paraffin with lower polymers content in the processor and higher for
embedding and you will like the results.


Tim


Date: Fri, 8 Jul 2011 09:44:51 -0700
From: "Paula Lucas" <plucas <@t> biopath.org>
Subject: [Histonet] Embedding Media
To: <histonet <@t> lists.utsouthwestern.edu>
Message-ID: <9251EDA88CA748D6861A0C3BB0E32FCB <@t> biopath.local>
Content-Type: text/plain; charset="us-ascii"

Hello,



We are considering a switch to a different brand of paraffin and this is
because I feel we are having too many compressions in some of our tissue
sections.  Currently, we use Tissue Path Paraplast, regular.



I would like to get feedback from you as to what you prefer.  Looking on
line, Richard Allan has a product called Signature Series Paraffin that
comes in a type L that offers compression-free sections and I was also
hoping to get any feedback on that product.



I would greatly appreciate any suggestions and thoughts.

Thanks in advance,

Paula





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