Helloo Histo techs.... I am having a very difficult time getting good tissues of Finch brains. I fix tissue in 4% paraformaldehyde. Afterwards in series of sucrose b4 gelatin embedding then fast freeze. After cutting, (-12 c in cryostat)I see "swiss cheese" type of tissue. It's wht our lab call tissue lysing. I can't figure out wht's going on....... can anyone help me? pls? thanks G.F.