IS-hybridisation: emulsion problem

[Mr. M.J. Smith]

I have a problem with some brain sections hybridised with an 35S labelled 
oligo probe, coated with Amersham LM-1 autoradography emulsion. 

A dense, yellow-brown non-specific stain is affecting the tissue 
sections. I have used the technique in the past with no problem and my 
feeling is that something is degrading over time in the emulsion. The 
staining is not due to light contamination (there are no background 
silver grains but a signal is appearing in appropriate areas), and is not 
due to the developing process.

I have contacted Amersham who are going to investigate the batch of 
emulsion. In the mean time I would be interested if anyone has had 
similar problems and what the cause is. Alternatively this is a dodgy 
batch of emulsion of which collegues should be aware, as lengthy 
experiments may be ruined.

Martin Smith
Cardiff University
Wales

email mjsmith at hgmp.mrc.ac.