[Immunocytochemical detection of the nonfibrillar stage of amyloid formation in the mouse myocardium].

The indirect electron microscope immunoperoxidase method utilizing pure rabbit antibodies to protein of mouse amyloid fibrils was used for studying casein-induced amyloidosis in mice. At the early stages of amyloidosis there appeared deposits of fine granular material in the mouse myocardium. These deposits contained an antigen similar to the amyloid fibrils antigen, but the deposits had no fibrillar ultrastructure. The results testify to the presence of early nonfibrillar stage of amyloid formation.