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Biomedical subjects

M Skinner

Publications and source records attributed to M Skinner.

At least 217 records · Page 12Linked to original sources
PubMed1977

Kinetics of serum amyloid protein A in casein-induced murine amyloidosis.

Serum amyloid protein A (SAA), the precursor of secondary amyloid protein, is elevated in chronic diseases which are associated with an increased incidence of amyloid. However, SAA is also elevated in acute bacterial and viral infections and somes forms of cancer. The murine model of casein-induced amyloidosis was studied to determine the relationship between SAA production and amyloid deposition. SAA levels measured by radioimmunoassay were found to be as high as 200 times the normal level in CBA/J mice receiving daily parenteral casein. After a single injection of casein the SAA level was elevated by 3h and peaked by 12-18 h. Similar levels were found in casein-treated A/J mice, a strain less susceptible to the induction of amyloid. Parenterally administered bovine serum albumin, which has low potential for amyloid induction, gave SAA levels in CBA/J and A/J mice comparable to casein treatment. These data show that, while SAA levels are elevated during chronic antigenic stimulation, there are other factors involved in amyloid formation. These factors may include alterations in the degradation of SAA by the reticuloendothelial system caused by substances such as casein. Nude (athymic) mice were shown to attain high levels of SAA after receiving casein parenterally. Therefore, thymus-derived lymphocytes are not necessary for the synthesis of SAA.

Amyloid↗
PubMed1977

Amyloid deposition in a renal transplant in familial Mediterranean fever.

A patient with familial Mediterranean fever and amyloidosis who received a cadaver renal transplant 6 1/2 years ago was studied to determine the relation of the serum precursor of secondary amyloid (SAA) to the clinical course and to the deposition of amyloid in the transplant. Amyloid fibrils extracted from the patient's kidneys contained protein AA as a major constituent, which identified the amyloid as secondary. Protein AA antiserum was used in an indirect immunofluorescent technique to stain amyloid deposits in sections of the original kidney. A renal biopsy at 2 years showed no amyloid, but a renal biopsy at 4 years showed amyloid. Serum levels of SAA from 3 years before transplant to 6 years after transplant were elevated throughout most of the course.

Adult↗
PubMed1977

Murine amyloid protein AA in casein-induced experimental amyloidosis.

Amyloidosis was induced in mice by 25 subcutaneous injections of casein. The splenic amyloid fibrils were identified by electron microscopy to be closely associated with reticular cells. After isolation of the fibrils by simple physical techniques, their ultrastructure revealed single filaments of 80 to 100 A width, which were rigid, nonbranching, and of indeterminate length. This is comparable to previous studies on human preparations. The amyloid fibrils were dissociated by solution in guanidine and chromatography. The resultant amyloid fibril protein was characterized as to its molecular weight, amino acid analysis, and amino-terminal sequence. It was thus definitely identified as protein AA, the major component of secondary amyloidosis. An antibody to this protein, murine AA, identified a cross-reacting mouse serum protein SAA and indicated a species specificity when tested against human preparations. A comparison is made with the AA protein in another murine model as well as AA proteins from human, guinea pig, monkey, and mink amyloidosis.

Amino Acid Sequence↗
PubMed1976

The surface morphology and the cell cycle of mastocytoma target cells: no apparent effect on cell-mediated killing.

Mastocytoma cells (P-185) have been separated by velocity sedimentation into fractions which were highly enriched for cells at discrete stages of the cell cycle. By scanning electron microscopy it was shown that the surface morphology of the majority of cells in each fraction was characteristic of that fraction. No difference could be detected between isolated fractions and unfractionated cells in their ability to be lysed by cytotoxic lymphocytes.

Animals↗
PubMed1976

The SJL/J mouse: a new model for spontaneous age-associated amyloidosis. I. Morphologic and immunochemical aspects.

A high incidence of spontaneous amyloidosis is described in SJL/J mice. Amyloid was detected as early as 30 weeks of age and the incidence rose to 90 per cent by 60 weeks of age. Amyloid deposits were most prominent in the perifollicular zones of the spleen and the lobular areas of the liver. Ultrastructural analysis revealed rigid, nonbranching fibrils indistinguishable from those observed in casein-induced murine amyloidosis. On the other hand, immunochemical studies indicated that amyloid deposits in SJL/J mice differ from those found in casein-treated CBA mice with respect to size, amino acid content, and antigenic properties. Since the SJL/J mouse also develops spontaneous reticulum cell tumors and serum M components, it appears to be a useful model for study of the pathogenesis of amyloidosis and its relationship to aging, neoplasia, and certain B-cell dyscrasias.

Age Factors↗
PubMed1975

The P-component of amyloid of human islets of langerhans.

The P-component of amyloid was found in extracts of pancreases with islet amyloidosis. In double immunodiffusion this P-component showed lines of identity with isolated purified human P-component, normal human serum, and an extract of amyloid-rich liver tissue from a patient with primary systemic amyloidosis. The finding supports the theory that the P-component is present in all native human amyloid irrespective of type.

Adolescent↗
PubMed1975

Antigenicity and cross-reactivity of denatured fibril proteins of primary, secondary, and myeloma associated amyloids.

Antisera have been produced against amyloid fibril preparations of primary, secondary, and myeloma origins. These have revealed the presence of both idiotypic and shared antigenic determinants. A high degree of cross-reactivity among the 3 types of amyloid has been found irrespective of classification. One antiserum to a secondary amyloid fibril preparation proved to be directed against A protein (the major nonimmunoglobulin constituent of secondary amyloid fibrils). This antiserum detected A protein in several of the secondary amyloids as well as in two primary amyloid fibril preparations which were degraded with alkali; These finding indicate that amyloid fibrils of various origins have similarities in composition and, therefore, may have common factors involved in fibrillogenesis.

Amyloid↗
PubMed1975

Amyloid fibril protein related to immunoglobulin lambda-chains.

Amyloid fibrils, isolated from the spleen of a patient with primary amyloidosis, had an N-terminal sequence showing a high degree of homology with lambda Bence Jones proteins. Anti-serum prepared to the amyloid protein detected a soluble factor, antigenically identical to the isolated fibril preparation.

Amino Acid Sequence↗
PubMed1974

Isolation and identification by sequence analysis of experimentally induced guinea pig amyloid fibrils.

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.

Amino Acid Sequence↗