Division of Radiooncology, Deutsches Krebsforschungszentrum, 69120 Heidelberg, Germany
Subsequent to immunohistological reaction, counterstaining of tissue sections with the thiazin dye toluidine blue (Toluidine blue O) is an alternative to other dyes (e.g. haematoxylin, carmine, methyl green) for nuclear staining. Moreover, the staining procedure is rapid and easily performed, thus, toluidine blue is helpful and widely employed for any kind of overview stainings. There exist formulations for cryostat and paraffin sections as well as for sections cut from resin embedded tissue.