At the Oregon Regional Primate Research Center, we used to leave skin
samples in barely molten paraffin over the weekend with good results.

Allen A. Smith, Ph.D.
Barry University
School of Graduate Medical Sciences
    Podiatric Medicine and Surgery
Miami Shores, Florida  33161-6695 

-----Original Message-----
From: Jeff Silverman [mailto:peptolab@hamptons.com]
Sent: Tuesday, May 21, 2002 8:26 PM
To: histonet@pathology.swmed.edu
Subject: Weekend delay holding "solution"


We recently (16 months ago) instituted a weekend per diem slot where a tech
comes in "sometime" over the weekend to have all the Friday slides done by
Monday at 8 AM. This gives us a "day without histo" Mondays (or three day
weekend Tuesdays) except a few recuts and specials, to catch up on stuff.
Well this tech used to come in on Staurday morning so we didin't use a
weekend delay. Then, she started to suffer from "shift creep" and before you
know it, she was coming in regularly on Sunday night early Monday morning,
unbeknownst to me. I caught her finishing late  one 7AM and she admitted she
had been doing the slides at the last minute for months. This, even on three
day weekends so the tissues sat in the last paraffin station for either 48
hours or as much as  72 hours.

Folks, this is the best run of the week. Everything is gorgeous, better than
during the week, even  endoscopic biopsies and curettings are perfect.
Nothing is cooked and hard as you might fear. Breast fat and bone cut like
butter. You should see the immunos! We run a Leica TP 1050. We fix in
Histochoice five hours, run one 70% one 95%, five absolute ethanol and two
xylenes  each for 40-45  minutes, all at ambient temp and with P/V cycling,
and three changes of plain old Paraplast at 62 C for one hour each.

We had previously experienced cooked rubbery hemolytic brown tissues when
pausing the tissues in the Histochoice over the weekend delay. This was on
an orange VIP wherein the retort sits directly over the paraffin pots and
the tissues  "simmer" in Histochoice all weekend. Nasty. I prefer our new
solution. Its really easy, we never have to worry about the delay. Its a
pleasure to see those slides. Of course, the tech is relaxed too so the
microtomy is perfect.

By the way. Another "holding" solution I recommend is to run with no delay
and have someone remove the baskets on Saturday morning to sit on a tray at
room temperature. You can put the baskets back in the paraffin reservoir on
the embedding center on Monday or Tuesday and they too benefit from this
treatment. I did it for 6 years with companion animal surgicals and they
were the easiest blocks to cut after cooling and remelting before embedding.
Any comments?
Jeff Silverman
Southside Hospital
Bay Shore NY USA