A combined fluorescent and electron microscopic stain for elastic tissue

Synopsis A histochemical procedure for fluorescent and electron microscopic observations of elastic tissue has been developed. This was accomplished by combining thein vivo andin vitro staining properties of non-metallic tetraphenylporphine sulphonate and its silver derivative. The non-metallic porphyrin gives a bright red fluorescence to elastica after injection, but it does not make the tissue electron dense. However, the metallic derivative imparts a specific electron density to elastica afterin vitro staining, but it does not render elastica either fluorescent or electron dense after injection. Thus, elastic tissue can be viewed with the fluorescence microscope after injection of the nonmetallic porphyrin. Sections from the same block can be stainedin vitro with silver tetraphenylporphine sulphonate and observed in the electron microscope. The nonmetallic porphyrin readily crosses the placental barrier and, therefore, can be used to study the elastica in foetuses by fluorescence microscopy.