RE: [Histonet] Sponge problems in processing

From:"S Ladd"

Good point about the vacuum. Also, with or without sponges there is going to
be carry over (in the tissue, in the chamber, in the hoses, clinging to the
casettes etc.) I was trying to do the math...
How much 95% alcohol (and ultimately how much water?) would be carried over
to the xylene station, if there were 200 mL of 95% alcohol retained, each
station contained 4000 mL of liquid and there were 3 100% alcohol stations
in between? I got a headache trying to figure out the dilutions and I gave
The point is, if we have an appropriate processing protocol with multiple
stations of alcohols, xylenes and paraffins and we make use of vacuum and
agitation and change our reagents often, then I think these fancy new
processors should be able to deal with the carry over of liquid retained in
the sponges. We put 200 cassettes on our processor, with 50-75% of the
cassettes containing sponges and UNLESS the P/V and agitation gets
mistakenly turned off, our specimens are appropriately processed. Of course,
this is just my opinion and if I had the time, I would do a couple little
University of South Florida

-----Original Message-----
[]On Behalf Of Marshall
Terry Dr,Consultant Histopathologist
Sent: Tuesday, April 06, 2004 11:21 AM
To: Steven E. Slap; Gayle Callis; Gudrun Lang;
Subject: RE: [Histonet] Sponge problems in processing

OK. 200 ml. of liquid retained, with 100 blocks.
However, with a vacuum processor, is that not all "sucked away"?

BTW, should it sound otherwise, I hate the things (but am stuck with them).

Dr Terry L Marshall, B.A.(Law), M.B.,Ch.B.,F.R.C.Path
 Consultant Pathologist
 Rotherham General Hospital
 South Yorkshire

-----Original Message-----
From: Steven E. Slap []
Sent: 06 April 2004 16:14
To: Gayle Callis; Gudrun Lang;
Subject: Re: [Histonet] Sponge problems in processing

Hi HistoNetters

I agree with Gayle, and the other posters who pointed out that
sponges carry over 1ml of fluid per sponge (so, with 100 cassettes,
200 sponges, that's a lot of carryover).

I have had a lot of success with the biopsy cassettes which Gayle
refers to, both in microwaves and in conventional tissue processors.
You can request samples from Lab Storage Systems in St. Louis by
phone at (800) 345-4167 or by e-mailing Rita Lovshe at

best regards,
Steven Slap

At 10:20 AM -0700 4/1/04, Gayle Callis wrote:
>To: "Gudrun Lang" ,
>From: Gayle Callis 
>Subject: [Histonet] Sponge problems in processing
>We no longer use sponges, prefer to place tissues in tissue embedding bags
>(Fisher) which look like tea bags or the little nylon bags (not as easy to
>handle, but thinner than sponges) and a tidge stiffer than tea bags.
>Sponges can cause artifacts in your tissues, looking like triangular holes
>in section.  This was published by Freida Carson in Journal of
>Histotechnology, 1980's.  Using tea bags may not be as fast during
>embedding, but speed there is a trade off for having to reprocess important
>tissue samples, ho hum tedious and time consuming while patient waits.
>You analysis of problem sound correct with a poor exchange of solvents
>through sponges. If you pack cassettes super tight in basket/cassette
>holder inside processor you can impede solvent flow or if sponges are
>crammed too tight agaist tissue then lid smashed down on tissue/sponge
>sandwich - this is like having too thick a tissue in a cassette.
>There are some clever biopsy cassettes with a folding, fine mesh inserts
>fitting inside a cassette.  These may be worth a try to avoid sponges. I
>think they are available through Fisher or some other company who could
>provide free samples.  It will be interesting to see peoples testimonials
>on using these.
>There was Histonet discussion on these sponges way back in time - it may
>pay to do a search for those messages in Histonet Archives.

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