[Histonet] Paraplast Plus

[Rittman, Barry R]

One point that has not yet been mentioned here is that paraffin is not a
single compound but a mixture of compounds with various compositions and
melting points. This is evident if you heat paraffin for some hours you
can drive off the lower melting point components etc. You can also
change melting point and cutting properties by the addition of various
substances such as ceresin.
Barry

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of pam
marcum
Sent: Wednesday, March 09, 2005 12:57 PM
To: MSafron <@t> wilresearch.com; Histonet <@t> lists.utsouthwestern.edu;
gcallis <@t> montana.edu
Subject: Re: [Histonet] Paraplast Plus

Gayle is giving the best advise you can get for any paraffin on the
market
today.  They all have additives and these problems can occur all of them
if
not properly stirred and mixed daily.  One question I have is do you
allow
the paraffin to re-solidify overnight?  IF so this can add to the
problem.



Pam Marcum 

 

-------Original Message-------

 

From: Gayle Callis

Date: 03/09/05 11:41:55

To: Mike Safron; Histonet <@t> lists.utsouthwestern.edu

Subject: Re: [Histonet] Paraplast Plus

 

We had trouble with this paraffin in the past:

 

Several things:

 

Although the droplet appear not miscible, have you tried stirring the

paraffin after melting to redistribute the plastic polymer additives,
etc

that are in the paraffin.  This should be done before embedding, and
before

adding any melted paraffin to processor paraffin containers, pots.
During

processing, agitaion should keep these resuspended.  Stirring paraffin

before embedding EACH DAY is advisable to keep additives (heavier so
they

settle to bottom of paraffin pots) suspended or you will run into

sectioning problems.  A plastic spatula is very handy for this purpose.

 

If stock paraffin is stored in a cold place and then melted,

water  condenses and  water droplets form in bottom of paraffin

pots/storage containers.  Store your stock paraffin at recommended

tempertures, cool, but not extremely cold place, dry.  We found room

temperature storage was adequate prior to melting.

 

Also, do not melt Paraplast Plus over 62C, high temperatures create
havoc

with this paraffin, and you may damage additives - we never exceeded 62C

for melting, storage or processing protocols.

 

Poor sectioning occured with high temperature melting of this paraffin
and

also not stirring it before embedding or dispensing into paraffin
processor

pots.

 

Clean storage pots and embedding centers frequently.

 

and At 08:21 AM 3/9/2005, you wrote:

>We are using Paraplast Plus from Kendall (Tyco/Healthcare).  We have
noticed

>that after the paraffin melts (in embedding center and paraffin pot)
that

>there is what appears to be a straw colored liquid that is deposited at
the

>bottom of the units.  It would appear that the liquid is not miscible
with

>the melted paraffin. This liquid is causing problems with embedding.
Does

>anybody know where this liquid is coming from?

 

Gayle Callis

MT,HT,HTL(ASCP)

Research Histopathology Supervisor

Veterinary Molecular Biology

Montana State University - Bozeman

PO Box 173610

Bozeman MT 59717-3610

406 994-6367 (lab with voice mail)

406 994-4303 (FAX)

 

 

 

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