Search

Amyloidosis was produced experimentally in guinea pigs by multiple casein injections. Amyloid fibrils were isolated and fractionated and a protein obtained that had an amino acid composition comparable with A protein, a unique nonimmunoglobulin constituent of secondary amyloid deposits. N-terminal sequence analysis demonstrated a sequence homologous with that of A proteins from human and monkey preparations but preceded by a 5-residue peptide which had an N-terminal histidine. A definite species specificity in A protein from human and guinea pig was identified on immunologic analysis.

Eighteen patients had definite calcium pyrophosphate dihydrate crystal deposition disease (pseudogout) as shown by clinical and roentgenographic findings plus results of synovial fluid analyses. Seventy-two percent of the patients had diabetes mellitus and 33% had hypertension. Hyperuricemia was an uncommon finding except in association with azotemia and in one patient who also had gout. All patients had typical calcium pyrophosphate crystals in the synovial fluid and one patient also had an unidentified crystal. The character of the synovial fluid appeared to relate to the duration of the acute attack. The fluid was generally of an inflammatory type. Chondrocalcinosis was present roentgenographically in all joints where crystals were found and often in several other joints. Simple therapeutic measures (arthrocenteses) usually relieved the acute articular symptoms.