Previous studies of neuron survival by the Priestley lab have confirmed with toluidine blue histochemistry that NeuN immuno - reactivity is a reliable marker of neuron survival after spinal cord injury [34]. (journals.plos.org)
To observe tissue mast cells, 6 - μm paraffin sections of fixed tissues were stained with toluidine blue (Sigma - Aldrich) and the total number of mast cells in each tissue unit was counted. (jimmunol.org)
They found enough evidence of a link between ortho - toluidine exposure and an increased risk of bladder cancer to call the chemical a known carcinogen, according to HHS. (scientificamerican.com)