Comparison of some murine and human amyloid preparations.

Amyloid fibres extracted from the spleen and liver of Swiss albino mice, in which amyloidosis was induced by repeated casein injections, and from SJL/J mice with amyloidosis secondary to spontaneous pleiomorphic reticulum cell sarcoma were compared with human amyloid secondary to rheumatoid arthritis and Hodgkin's disease. The murine preparations resembled human amyloid in the green birefringence after congo red staining. Fibrillar structures, single or pairs, 70 Å in diameter and 700-2200 Å in length, similar to human amyloid, were revealed by electron microscopy. On the other hand, a marked dissimilarity in the chemical composition of murine and human amyloid was observed. The murine preparation contained a high lipoprotein and DNA content while in human amyloid only trace amounts of lipoprotein were detected in amyloid secondary to rheumatoid arthritis.