[Histonet] Embedding Question

[WILLIAM DESALVO]

Cooling the paraffin and then re melting will not affect the tissue, unless the combined heated, liquified state period becomes extended. Cooling the paraffin is a great protector of the tissue, no different than what you have with a completed block. Be cautious at how fast and at what temperature you reheat at.
With dry embedding, you have to be cautious about small tissue pieces obtaining a drying or heat affect. The small tissue pieces are typically at the bottom of the cassette and closest to the heating element, without the insulation of the liquid paraffin. Wet embedding there is a possibility of debris tissue fragments floating amongst the cassette. Both methods require cleanliness and short times in liquid paraffin to embedding. 

Sent from my iPhone

> On Mar 12, 2015, at 10:09 AM, Lucie Guernsey <lguernsey <@t> ucsd.edu> wrote:
> 
> If I may, I'd like to piggy-back onto what Paula has mentioned regarding
> allowing paraffin infiltrated tissue to cool before embedding it. Hopefully
> someone can help both of us out, even if we seem to warm our infiltrated
> tissue differently (Paula's in a dry bin and mine in a wax bath).
> 
> I work in a research lab where we work in large batches and time is not a
> priority like it is in a clinical setting. Rather than leaving 60-80
> cassettes of infiltrated tissue soaking in a hot wax bath for hours at a
> time, we've begun to allow the cassettes to cool and just toss a handful of
> cassettes into the wax bath 5-10 minutes before we're ready to embed that
> batch of cassettes. Sometimes we don't even embed the cooled tissue until
> the next day or later that week. I haven't noticed an obvious difference in
> how our blocks section, though we have troublesome batches sometimes and we
> haven't been able to put our finger on why.
> 
> Anyone know if allowing infiltrated tissue to cool and then reheat before
> embedding is better or worse than keeping the tissue soaking in wax for
> hours at a time?
> 
> Thanks!
> Lucie
> 
> Lucie Guernsey
> UC San Diego
> lguernsey <@t> ucsd.edu
> 
> 
> 
>> On Thu, Mar 12, 2015 at 9:43 AM, Paula Sicurello <patpxs <@t> gmail.com> wrote:
>> 
>> Hi Tim,
>> 
>> There are several embedding events through-out the day, though mostly in
>> the wee hours of the morning.  The embedding centers would be in the same
>> room as the  microtomes (another question about those tomorrow).
>> 
>> I worry about the small (GI, needles, etc) biopsies freezing before they
>> reach the embedding stations.  In my experience, once they freeze they get
>> this outer wax coating (like a permeability barrier) which doesn't melt
>> when placed in the dry (no paraffin inside) but hot, holding bin.
>> 
>> They just don't seem to embed that well and have a tendency to drop out of
>> the sections when cutting.
>> 
>> Has anyone else had that happen?
>> 
>> Paula
>> 
>> On Thu, Mar 12, 2015 at 9:07 AM, Morken, Timothy <Timothy.Morken <@t> ucsf.edu>
>> wrote:
>> 
>>> Paula,
>>> How many times per day?
>>> Is the embedding close to the cutting area?
>>> 
>>> Of course any extra walking is a problem, especially in busy areas. Is
>>> this a non-patient area (hopefully!)? Any restructuring should be to move
>>> things closer together, not further away!
>>> 
>>> Having said that, If it comes to that I would be more concerned about
>>> embedding proximity to the cutting area since having embedding near
>> cutting
>>> enhances workflow and cross coverage. If you don't unload processors very
>>> often then having them distant might not be too bad. Not ideal, but not a
>>> necessarily a deal killer.
>>> 
>>> 
>>> Tim Morken
>>> Pathology Site Manager, Parnassus
>>> Supervisor, Electron Microscopy/Neuromuscular Special Studies
>>> Department of Pathology
>>> UC San Francisco Medical Center
>>> 
>>> 
>>> 
>>> -----Original Message-----
>>> From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:
>>> histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Paula Sicurello
>>> Sent: Thursday, March 12, 2015 6:29 AM
>>> To: HistoNet
>>> Subject: [Histonet] Embedding Question
>>> 
>>> It has been proposed to move the embedding centers to a room about 210 ft
>>> away from the tissue processors.
>>> 
>>> The trip from processor to embedding center would take over 2 minutes and
>>> require the histotechs to carry the baskets full of cassettes down a much
>>> used hallway.
>>> 
>>> Opinions?
>>> 
>>> Do you feel this is a good idea-yes or no and why?
>>> 
>>> Thanks in advance,
>>> 
>>> Paula
>>> _______________________________________________
>>> Histonet mailing list
>>> Histonet <@t> lists.utsouthwestern.edu
>>> http://lists.utsouthwestern.edu/mailman/listinfo/histonet
>> _______________________________________________
>> Histonet mailing list
>> Histonet <@t> lists.utsouthwestern.edu
>> http://lists.utsouthwestern.edu/mailman/listinfo/histonet
> _______________________________________________
> Histonet mailing list
> Histonet <@t> lists.utsouthwestern.edu
> http://lists.utsouthwestern.edu/mailman/listinfo/histonet