Hello all,

The following is a sealant called VALAP and originated by Bob Allen in
60's.  The VALAP recipe is:  1/3 paraffin (56 degree type works well), 1/3
vaseline, 1/3 lanolin by weight, lightly heat and mix.  Carefully melt and
stir. IT IS FLAMMABLE.  It is nice because it is easy to make, stores well
as a soft solid and is easy to apply to seal coverslips with a artist's
paint brush after lightly heating to a liquid.  Be careful because it burns
easily!  With the help of Nina Allen and Bob Hard I was able to locate at
least one of the original references.  It is:   McGee-Russel, S and Allen,
RD (1971). Reversible stabilization of labile microtubules in the
reticulopodial network of Allogromia. Advances in Cell and Molecular
Biology 1: 153-184.  It mentions the VALAP recipe and the metal slide idea
used to hold double coverslip preps.  The article also mentions apparent
lack of toxicity from the VALAP.   Nina mentions that there is permeability
at least of oxygen and that is why her cell types do so well with the VALAP
over longer time periods. As Bob Hard points out: "Regarding the aluminum
slides (actually in Bob's lab and in mine, they were/are made from brass,
which doesn't bend as much)..."  The article also describes the design of
an elegant microperfusion chamber and a technique for correlative light and
TEM.  Reading the technique reinforces the need for an experienced lab hand!

Hopes this helps propel science down the road.
Louie

Louie Kerr
Research and Education Support Coordinator
Marine Biological Laboratory
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Woods Hole, MA  02543
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