Increased yield of immunogold labeling of epoxy sections by adding para-phenylendiamine in the tissue processing.

The purpose of this study was to examine if the presence of para-phenylendiamine (PPD) in the tissue processing could increase the yield of immunogold labeling of the epoxy sections. Renal swine tissue with glomerular immune complex deposits with reactivity against IgG was embedded in epoxy resin. PPD was added (1) at the beginning of the dehydration, (2) in the first step with propylene oxide, (3) in the beginning of the dehydration and in all steps with propylene oxide included the infiltration step where propylene oxide and epoxy resin are mixed, or (4) PPD was totally avoided.