[Histonet] Bubbles (Was Re: coverslippers). Also DPX

[John Kiernan]

Could your bubble trouble be from the medium rather
than the machine?

We have used cytoseal mounting media, which are 
poly(methylmethacrylate) with different viscosities,
for several years. We apply coverslips manually. Bubbles
that form near the edge of the coverslip are a regular 
occurrence, but it doesn't matter unless they occlude the
specimen. The low price and ease of application of this
mountant, which is also non-fluorescent, largely offset 
this bubble problem. A cooler hotplate suppresses or
minimizes the bubble formation.

Bubbles (other than from human error) never happened when
we used DPX, a polystyrene-based mountant.  DPX bought since 
about 1985 has contained tiny transparent droplets that can
really get in the way when looking at sections more than 
10-20um thick. When this problem arose, our suppliers 
recommended using entellan instead. Entellan is an expensive
poly(methylmethacrylate) mountant that comes in a glass
bottle - more troublesome to apply than squeezing
cytoseal out of a plastic bottle with a narrow nozzle.
With entellan we didn't get the new-DPX droplets or the
bubbles at the edges of the coverslip that often occur
with cytoseal.

DPX was a published, non-secret resinous mountant that
was almost perfect. Making it in-house was never a
serious option because you could not easily buy the
polystyrene ingredient from ordinary lab supply companies.
We relied on vendors. The product from BDH was excellent
in every way.
 
Does anyone know a current source of DPX that meets the
published (early 1950s) specs? It needs to be visibly
transparent (not yellowy), devoid of autofluorescence,
without microdrops that show up in thick preparations.

Patricia Traphagen's bubbles may originate from a subtle
imbalance between the volatility of the clearing agent
and the viscosity of the mountant.  Just a few thoughts 
to tickle up some more discussion!

John Kiernan
London, Canada.
------------------------------------------------------ 
"Traphagan, Patricia" wrote:
> 
> We are having major air bubble problems after we have coversliped our
> slides using the Leica coverslipper. We use Cytoseal and Richard Allen
> coverslippers. We set the dials at 2.5 volume and 1 mountant type.
> 
> Patty Traphagan
> Histology Technical Specialist
> Methodist Hospital Laboratory
> 952-993-2823 or 952-993-5304
> 
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