Hi Histonetters,

Just did a search of the archives and found a post by Gayle, who
normally uses 100 bloom gelatin (type A) but says that 275-300 bloom
(type B) works best for decal bone (not soft tissues).

I have been subbing slides with what we already had in the lab here,
probably 3+ years old, a Type B 225 bloom.  I section rodent brain at 50
um, and do have section adherence problems (must narrow down the
cause...more thorough cleaning, subbing untreated (rather than plus
slides) slides, bloom of gelatin, adding solution of chromium K sulfate
separately after gelatin dissolves).  

QUESTION:  Should I be using the Type A (from porcine skin) 75-100 bloom
gelatin for fixed cryostat sections of brain?  I am not concerned with
background staining since the types of stains I do have not caused
background stainging with the 225 bloom.

Also:  what percentage of section loss is common?  Does anyone have
95-100% adherence or is losing sections commonplace and something to be
factored in when collecting sections?  (I have been factoring it in
since I have lost sections...less during nissl staining than for the
cytochrome oxidase and acetylcholinesterase histochemistries).

Thanks for the feedback...

Stephanie Moore
Brandeis University
Waltham, MA 02454
781-736-3182