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Replacement of Xylene by Leica ST Ultra and Leica CV Ultra
Leica ST Ultra and Leica CV Ultra have been developed to replace Xylene/Toluene and conventional mounting
media in histopathology/Cytopathology laboratories.
Leica ST Ultra is used for clearing; Leica CV Ultra is used for coverslipping (mouting)
Leica ST Ultra and Leica CV Ultra both are:
Leica Microsystems
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Leica ST Ultra
Leica CV Ultra
- Non flammable
- Odourless
- No detectable aromatics
- Non carcinogenic
- Non poisonous
- Environmentally and human friendly
There are two typical processes in a histo/cytopathology laboratory:
- Tissue Processing
- Deparaffination, Staining and Coverslipping
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Leica Microsystems
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Leica ST Ultra
Leica CV Ultra
Change to Leica ST Ultra in Tissue Processing
The general procedure for tissue processing is documented
below, although slight variations exist from one laboratory to
another.
Sequence Time in minutes Temperature °C
Formaldehyde 10 % v/v 30 40
Formaldehyde 10 % v/v 60 40
Ethanol 50 % 30 40
Ethanol 70 % 30 40
Ethanol 100 % 30 40
Ethanol 100 % 60 40
Ethanol 100 % 60 40
Ethanol 100 %* 120 40
Xylene 40 40
Xylene 80 ** 40
Paraffin 60 60
Paraffin 60 60
Paraffin 60 60
Paraffin 120 60
If Xylene is replaced by Leica ST Ultra it is important to note the following:
* More frequent refreshment of 100% Ethanol for tissue dehydration might be
necessary since xylene is partially miscible with water. Leica ST Ultra is not.
** Time of clearing should be increased by 30 minutes. Xylene penetration of
tissue is faster than penetration with Leica ST Ultra.
Performance advantage of Leica ST Ultra
Leica ST Ultra hardens fragile tissue material to a lesser
degree than Xylene (e.g. lymph nodes and testes).
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Leica Microsystems
Change to Leica ST Ultra and Leica CV Ultra
in deparaffination, staining and coverslipping
In these procedures Xylene can be directly replaced by Leica
ST Ultra
It is important to use Leica CV Ultra with Leica ST Ultra since
Leica ST Ultra is not compatible with conventional mounting
media, such as DPX, Pertex, Entallan, Eukitt etc ...
The use of Leica CV Ultra is extremely flexible. Leica CV Ultra
can be used with Leica ST Ultra and also with Toluene and
Xylene.
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Leica ST Ultra
Leica CV Ultra
Troubleshooting hints
Cutting problems
Water remaining in tissue. Re-
fresh final Ethanol bath in dehydration process.
Ethanol remaining in tissue.
Time in Leica ST Ultra too
short. Increase steps or time
of Leica ST Ultra.
De-paraffination problems
Leica ST Ultra saturated with
paraffin.
Leica ST Ultra should be re-
freshed.
Water remaining in tissue.
Last 100 % Ethanol bath in dehydration process should be
refreshed.
Tissue badly stained
Fixative use not optimised.
Buffered Formaldehyde
10 v/v% is advised.
Problems with staining solu-
tions.
Tissue slices too thick
Tissue not completely de-
paraffinated.
Slide appearance is milky
during coverslipping
Leica ST Ultra use in final
bath, together with a conven-
tional mounting medium. Use
Leica CV Ultra for the best fit.
Final dehydration not com-
plete. Refresh final bath of
100% Ethanol more fre-
quently.
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Leica CV Ultra versus Pertex
Leica Microsystems
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Leica ST Ultra
Leica CV Ultra
Cytology lab technicians sometimes prefer
Pertex, because of very quick fixing.
Tests were done and Pertex mounts a bit faster
than CV Ultra. Initial fixing takes about 5 min
versus 10 min for CV Ultra. But after 1 hour the
CV Ultra and Pertex mount the coverglass to the
same extend.
Details
Sticking performance tests were done, by mounting a
coverglass on a microscopic slide after a bath of
Xylene. Xylene was used, because Pertex infridges
with Leica ST Ultra. *
The time needed for the initial fixing was checked.
Also viscosity has been checked and Pertex and CV
Ultra have more or less the same viscosity. So there is
a small difference but for cytology use CV Ultra is very
well applicable. Please find an overview of the properties of both products in the table below.
* Leica ST Ultra will be available from Dec. 2001 on.
Criteria Leica CV Ultra Pertex (Histoline)
Initial mounting 10 min. 5 min.
Mounting after
one hour OK OK
Contains Xylene NO YES!
Viscosity Equal Equal
Can be used with
Xylene, STUltra, YES Only Xylene
IPA
Thickens when NO YES, addition
used of Xylene is
necessary
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Leica CV Ultra Mounting medium
Leica ST Ultra
Histowax
Leica Microsystems
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Leica ST Ultra
Leica CV Ultra
For all common robotic coverslippers as well as for manual
coverslipping procedures. This
coverslipping reagent does not
contain any dangerous organic
solvents.
6 bottles - 100 ml each, in a cardboard box.
0709 36261
Leica ST Ultra is designed to be
used as a Xylene replacement
during tissue embedding, deparaffination processes and coverslipping.
If used for coverslipping it can
only be used with Leica CV Ultra.
1 Tin can, 10 l.
0709 36260
Histowax - 1 Bag (contains 1 kg)
Minimum order quantity:
12 bags of 1 kg in a cardboard box
0374 32123
Histowax - 1 Box ( contains 15 kg)
(= 1 cardboard box with plastic
foil lining inside, no individual
bags)
0374 32124
MI CR OSYST E MS
Leica ST Ultra and Leica CV Ultra are both designed and manufactured for optimised performance when used
together. Please note that Leica ST Ultra will dissolve more Leica Histowax compared with other commercially
available paraffins. This reduces solvent usage substantially
Leica ST Ultra and Leica CV Ultra are tradenames of Leica Microsystems. Leica ST Ultra and CV Ultra are manufactured by J.T. Baker,
Netherlands for Leica Microsystems.
Leica Microsystems Nussloch GmbH, Postfach 1120, Heidelberger Strasse 17-19, D-69226 Nussloch, Germany
Phone: +49-6224-143-0, Fax: +49-6224-143-105
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