Someone (I don't remember who) wrote a few days ago saying their 
pathologists were complaining about poor nuclear staining. We had that 
problem a few years ago in Dallas. The nuclei were hazy, indistinct, and 
pale. There was little or no chromatin pattern. We called them "ghost 
nuclei." We traced the problem back to a change in the type of paraffin we 
were using. We had switched from regular Paraplast to Paraplast Extra 
because it seemed to section better. When we switched back, the staining 
improved, but sectioning wasn't as easy. We compromised by using both, 
regular Paraplast for processing and Paraplast Extra for embedding and that 
seemed to satisfy everyone. Someone (again I don't remember who)told me that 
Paraplast Extra was more sensitive to heat and if the slides were dried at 
very high temperatures it was more difficult to deparaffinize the sections. 
As I recall, our drying ovens (Lipshaw) were set about 80C, if not higher, 
in an effort to save time (money?) because the pathologists wanted their 
slides yesterday. Lowering the drying temps would have been a more logical 
solution, but when do we allow logic to interfere with speed?
Hope that helps.
David Anderson
Riyadh Armed Forces Hospital
Riyadh, Saudi Arabia
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