Kathleen:

Tissue is no more than 3mm. thick.  We fix the clinical tissue during
the day as we collect specimens.  There is no washing and they go
directly into the overnight processing.  Our mouse tissue is fixed
overnight (no more), then tissue is placed in 70%ethanol until ready to
be processed. At this point you can process as usual or skip formalin
and start with 70%eth.

Milton

-----Original Message-----
From: Kathleen Roberts [mailto:kgrobert@rci.rutgers.edu]
Sent: Wednesday, August 13, 2003 10:59 AM
To: Gomez, Milton
Subject: Re: Tissue processing problems


Only 4 hours in formalin...Do you trim your tissues before putting them
in
formalin?
And do you wash out the formalin before processing? If so, how long do
you
wash them?

Thanks for your help!
Kathleen

"Gomez, Milton" wrote:

> Dear Kathleen:
>
> All of our harderning problems have been due to overdehydration.
Here's
> our overnight protocol and it works wonders for most tissues,
including
> rodents:
>
> 1.10%formalin-4hours
> 2.70%ethanol-50'
> 3.80%ethanol-50'
> 4.95%ethanol-45'
> 5.95%eth.-55'
> 6.100%eth.-45'
> 7.100%eth.-55'
> 8.xylenes-45'
> 9.xylenes-55'
> 10.paraffin-40'at 59degrees x3times
>
> Our retort temperature is set at 34 degrees and our oven at 60
degrees.
>
> You may call me or write if you have any questions.
>
> Good luck in the name of our profession.
>
> Milton
>
> -----Original Message-----
> From: Kathleen Roberts [mailto:kgrobert@rci.rutgers.edu]
> Sent: Tuesday, August 12, 2003 10:32 PM
> To: HistoNet@pathology.swmed.edu
> Subject: Tissue processing problems
>
> To all-
>
> We are a small university pathology lab that does mostly rodent and
some
>
> fish tissues, and lately they have been coming out of the processor
hard
>
> as a rock and very difficult to cut, and we have been trying to figure
> out what, if anything, we are doing wrong.  We have tried changing out
> the reagents more often, but it doesn't seem to have made a
difference.
> We doubt that it's the temperature of the paraffin, as our settings
are
> in agreement with the manufacturer's recommendations, and the
> temperature displayed agrees with our thermometer. Could you please
send
>
> me your processing protocols for comparison?
>
> If you like, I will send you our protocol as well.  Any and all ideas
> and suggestions will be very welcome.
>
> Thanks in advance for your help-
> Kathleen Roberts
> Principal Lab Technician
> Neurotoxicology Laboratories
> Molecular Pathology Facility Core
> Dept of Pharmacology & Toxicology
> Ernest Mario School of Pharmacy
> Rutgers University
> 41 B Gordon Rd
> Piscataway, NJ 08854
> (732) 445-6914
> FAX (732) 445-6905