Biomedical subjects
Publications and source records attributed to Y Levo.
Two patients with gout and amyloidosis are reported. In contrast with other forms of chronic arthritis gout is apparently not associated with an increased incidence of amyloidosis. The possible reasons for this exception are discussed.
Papillon-Lefevre syndrome (PLS) is characterized by palmoplantar hyperkeratosis and by premature periodontal breakdown. In view of recent suggestions that this syndrome is associated with increased susceptibility to infections we decide to evaluate several immunological parameters in PLS patients and their healthy siblings and parents. PLS patients, as well as their siblings and parents, had a significantly impaired reactivity to both T and B cell mitogens. This in vitro abnormality was not associated with increased susceptibility to infections. The relationship between the impaired in vitro response to mitogens and the predilection for dermatologic and dental manifestations of PLS is discussed.
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Subsequent liver scans with both 99mTc-colloid and 99mTc-diphosphonate in a patient with biopsy proven liver amyloidosis are described. The colloid liver scans demonstrated the variable pattern which can be obtained at different stages of the disease, whereas, the absence of Tc-diphosphonate uptake, by the infiltrated liver, did not confirm previous suggestions about the amyloid seeking properties of this material.
Two out of fifty-three patients with macroglobulinemia developed acute leukemia following chemotherapy. The Phytohemagglutinin (PHA) Transformation Index performed prior to the appearance of acute leukemia was found to be markedly depressed in these two patients in comparison with ten other patients with macroglobulinemia. In addition, a clone with monosomy 7 was detected in one of the currently reported patients when the leukemic process became apparent. The cytogenetic analysis was normal in the same patient 48 months earlier, when macroglobulinemia was diagnosed. The low PHA Transformation Index and the chromosomal hypodiploidy are of interest and their clinical significance merits further investigation.
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Endotoxin has been shown to induce amyloidosis in mice and to result in the appearance in serum of large amounts of amyloidrelated protein (SAA). After injection of 300 mug lipopolysaccharide Escherichia coli, SAA behaves as an acute phase reactant with levels reaching a peak of >600 mug/ml at 18-22 h and returning to base line (<50 mug/ml) by 48 h in each of four strains tested; only the endotoxin-resistant C3H/HeJ strain showed a smaller response. Lesser, though significant, elevations were also found after subcutaneous injection of 25 mg of casein, bovine serum albumin, ovalbumin, or monomeric immunoglobulin G, whereas pyrogen-free human serum albumin/U. S. Pharmacopeia failed to raise SAA levels. SAA generation may thus be a result of endotoxin contamination of these protein preparations. Also present in equivalent amounts in acidified serum from endotoxin-treated mice, but barely detectable in control sera, was a 3,000-dalton molecule whose amino acid sequence is identical to the amino terminal 24 residues of mouse albumin. The appearance of SAA and the amino terminal albumin fragment after endotoxin were unaffected by pretreatment with cobra venom factor, and equivalent levels were found in C5-deficient mice. Pretreatment with pepstatin in vivo, or before acidification in vitro, prevented the appearance of the albumin fragment but had no effect on the appearance of SAA, whereas leupeptin and antipain did not affect the appearance of either SAA or the albumin fragment. These studies suggest that the generation of SAA after endotoxin administration does not involve complement activation or intravascular proteolytic activity, whereas the liberation of a specific peptic-like cleavage product of albumin appears to be the consequence of an acid protease.
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Amino acid sequence studies of the amino terminal 25 residues of amyloid A (AA) protein and the serum precursor (SAA) induced with casein or LPS indicate differences in the sequence at position 6 and significant heterogeneity at several other positions in SAA. These findings suggest that SAA is a polymorphic serum protein and raise the possibility that only certain forms of SAA are processed to the tissue amyloid fibril.
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