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Biomedical subjects

M Skinner

Publications and source records attributed to M Skinner.

At least 199 records · Page 11Linked to original sources
PubMed1982

Senile cerebral amyloid. Prealbumin as a common constituent in the neuritic plaque, in the neurofibrillary tangle, and in the microangiopathic lesion.

Three lesions that characterize the nosologic findings in the brain of Alzheimer's presenile dementia and senile dementia of Alzheimer type, ie, neuritic plaque, neurofibrillary tangle, and microangiopathy, all are frequently associated with amyloid deposition. There has been some question, however, as to whether these lesions share the same etiology. Moreover, the specific chemical nature of amyloid associated with these lesions has not yet been determined. In the present study, formalin-fixed paraffin sections of the affected brains were tested immunocytochemically for their reactivity against antiserum to prealbumin (recently disclosed as the major constituent of amyloid associated with familial amyloidotic polyneuropathy as well as senile cardiac amyloid) and known components of other types of amyloid (AA, AP, etc.). The results demonstrated that amyloid deposits in all three lesions reacted with anti-prealbumin, suggesting that it is a common constituent of these lesions. Indeed, it is likely that prealbumin is the major constituent of amyloid associated with neuritic plaque, neurofibrillary tangle, and microangiopathy.

Alzheimer Disease↗
PubMed1982

Immunohistochemical evidence for the lack of amyloid P component in some intracerebral amyloids.

Sections of brain tissue from patients with Alzheimer's disease with amyloid deposits in vessels, in plaques, and within nerve cells were studied by means of an immunoperoxidase method using a specific antiamyloid P component (AP) antiserum. Amyloid deposits in vessels were found to be strongly positive for protein AP, whereas the Alzheimer's plaques and the neurofibrillary tangles were negative or only weakly positive. The absence of protein AP in some intracerebral amyloid deposits might be due to an inability of the protein AP in some intracerebral amyloid deposits might be due to an inability of the protein to penetrate the blood-brain barrier. These findings support the theory that protein AP is absorbed to already formed amyloid fibrils, but the possibility that it may participate in the formation of vascular amyloid cannot be dismissed. The findings also indicate that protein AP is not necessary for the formation of amyloid fibrils at least in some forms of cerebral amyloidosis.

Alzheimer Disease↗
PubMed1982

Further characterization of amyloid-enhancing factor.

Amyloid-enhancing factor (AEF) is a transferable activity that in CBA/J mice reduces the induction time of splenic amyloid deposition to 48 hours. Azocasein, or AgNo3, can induce AEF in the spleen and liver. In the liver several subcellular organelles possess this activity. This is likely due to AEF's adherent properties. AEF is most effective when given by the intravenous route. After intravenous injection, AEF particulates localize to the perifollicular areas of the spleen and Kuppfer cells in the liver. The effects of AEF administration persist for at least 4 weeks. AEF can be solubilized in 4 M glycerol, is not the amyloid A protein, and is not likely to be the serum amyloid P component. The extract can be fractionated by Sepharose 4B column chromatography. The active component is of high molecular weight, and tentative identification by disc electrophoresis has been made.

Amyloid↗
PubMed1981

Immunocytochemical identification of amyloid in formalin-fixed paraffin sections.

Formalin-fixed paraffin sections of livers, spleens and kidneys from patients with primary, secondary and familial amyloidosis as well as from a casein-induced murine amyloid model were analysed by an immunocytochemical (unlabeled antibody enzyme) method utilizing antisera to amyloid-related proteins. All amyloid deposits of all amyloid types showed positive reactions with anti-AP of the respective species. Positive reaction of anti-human AA to human secondary amyloid deposits and of anti-mouse AA to the deposits of casein-induced murine amyloid was also observed, but there was no species cross reactivity. No significant deposition of the reaction products was produced by anti-immunoglobulin light chains on deposits of any amyloid type, or by anti-AA in the tissues from primary or familial amyloidosis. The results indicate that amyloid proteins AA and AP can survive as antigens through routine histologic preparation, that anti-AP can be a universal marker for deposits of any amyloid type within the same species, and that AA-type amyloid can be identified by this method while there may as yet be no feasible universal marker for the AL-type at present.

Amyloid↗
PubMed1981

Digoxin sensitivity in amyloid cardiomyopathy.

Digoxin (5 mg/ml) was added to 10-mg and 20-mg pellets of purified primary and secondary amyloid fibrils, a normal human liver and heart homogenate and a homogenate from the heart of a patient with amyloid cardiomyopathy who had not received digitalis. After centrifugation, the supernatants were recovered and assayed for digoxin concentrations. Aliquots from the sediments were studied for the presence of digoxin, using rabbits antidigoxin antiserum and an indirect immunofluorescent technique. The results showed that 0.11--0.13 ng/ml of digoxin bound per milligram of fibrils and could not be separated by repeated washings. Elution with citrate or changes in the pH of the buffer. Immunofluorescent studies demonstrated diffusely bright immunofluorescence with the fibril preparation and amyloid heart homogenate when reacted with digoxin and digoxin-specific antiserum. These studies demonstrate that isolated amyloid fibrils bind digoxin and suggest that this interaction may play some role in the sensitivity to digitalis that has been observed in some patients with amyloid cardiomyopathy.

Amyloid↗
PubMed1981

Enzyme-linked immunosorbent assay of serum protein SAA in rhesus monkeys with secondary amyloidosis.

Tissue deposits of amyloid protein AA and a concomitant elevation of serum protein SAA have been demonstrated previously in mice and humans with secondary amyloidosis, but not in rhesus monkeys (Macaca mulatta). In this study, protein SAA was quantitated in normal and amyloidotic rhesus monkeys using an enzyme-linked immunosorbent assay. Protein AA was isolated from the liver of a rhesus monkey with secondary amyloidosis by a combination of water extraction and gel filtration chromatography. The purified material had rigid, nonbranching fibrillar structures typical of amyloid on electron microscopy and a molecular weight of 9000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The amino acid content and partial sequence were comparable to those reported previously for protein AA of rhesus monkeys. As measured by enzyme-linked immunosorbent assay, normal rhesus monkeys had SAA levels of 40 to 64 ng. of AA equivalents per ml., whereas amyloidotic rhesus monkeys had SAA levels of 1700 to 95,000 ng. of AA equivalents per ml. An elevation of protein SAA was also detected in an amyloidotic pigtailed macaque (Macaca nemestrina) using rabbit antirhesus protein AA. Rabbit antisera against human and mouse protein AA reacted strongly with rhesus protein AA and with amyloidotic rhesus serum, but only slightly with normal rhesus serum, indicating that rhesus proteins AA and SAA have antigenic determinants cross-reactive with protein AA of xenotypic species.

Amino Acid Sequence↗
PubMed1980

Protein AA and lattice corneal dystrophy.

A 73-year-old woman underwent corneal transplantation because of lattice dystrophy. Histopathologic examination of the excised host cornea disclosed eosinophilic deposits that stained positively with Congo red and showed green birefringence with polarized light. Immunofluorescent examination showed protein AA and protein AP in the stromal deposits. To the best of our knowledge, this is the first report of protein AA and protein AP in the amyloid deposits of lattice corneal dystrophy.

Aged↗
PubMed1980

The effect of levamisole in experimental murine amyloidosis.

In casein-induced murine amyloidosis various lines of investigation have implicated immunodeficiency as playing a role in amyloid formation. In this study, the immunopotentiating agent levamisole failed to prevent amyloidogenesis or to accelerate resolution of preformed amyloid deposits in the mouse model. The serum precursor of amyloid, serum amyloid protein A (SAA), was increased by levamisole in both normal and amyloidotic mice.

Absorption↗
PubMed1979

Binding of serum amyloid P-component (SAP) by amyloid fibrils.

Serum amyloid P-component (protein SAP) was found to bind in vitro to isolated amyloid fibrils of both primary and secondary types. The binding was strictly calcium-dependent, optimal uptake requiring at least 0.5 mM calcium ion. Using normal human serum as the source of protein SAP different fibril preparations became saturated with between 5--20 micrograms of SAP per mg dry weight of fibril. Isolated pure protein SAP bound in greater amounts. In control experiments SAP did not bind significantly to collagen fibrils, sheep erythrocytes, plastic shavings, or the following immobilized proteins: human kappa or lambda Bence-Jones proteins; human; rabbit or mouse IgG; human serum albumin. C-reactive protein, which resembles protein SAP structurally but has calcium-dependent specificity for different ligands, bound significantly to only one of five different amyloid fibril preparations.

Amyloid↗
PubMed1979

Serum amyloid P-component levels in amyloidosis, connective tissue diseases, infection, and malignancy as compared to normal serum.

A highly sensitive radioimmunoassay was developed to measure the serum levels of SAP. Sera from 50 normal individuals ranging in age from 4 to 89 years had a mean level of 7.47 mg/dl and showed no variations with age. Sera from persons with various clinical types of amyloidosis, connective tissue diseases, and bacterial pneumonia did not differ significantly from normal values. A significant difference was noted in the sera from persons with malignancy, where a mean value of 10.79 mg/dl was determined. Although a number of similarities exist between SAP and CRP, SAP does not share the property of being an acute-phase reactant.

Adolescent↗
PubMed1978

The identification of amyloid P-component (protein AP) in normal cultured human fibroblasts.

The amyloid protein, AP, has not previously been detected in normal or nonamyloidotic tissues. In this study, human fibroblasts were examined for the presence of AP by immunofluorescence technique. Normal human skin fibroblasts were cultured in Eagle's minimum essential medium for varying periods of time. Antiserum was prepared in rabbits using AP isolated from amyloid-rich tissues. Using indirect immunofluorescence and anti-AP, fluorescent material was found to be distributed in a punctate pattern throughout the cytoplasm with sparing of the nucleus. The fluorescent reaction was speicifically inhibited by absorption of anti-AP with AP-positive serum but not by addition of AP-negative human cord serum. Thus, AP may have a fibroblast origin and a relationship to normal connective tissue.

Amyloid↗
PubMed1978

Amino terminal sequence of amyloid P-component isolated from serum.

Amyloid AP (protein SAP) has been isolated from human serum by affinity chromatography using specific antiserum and shown to have the same immunologic and ultrastructural characteristics as the pentagonal protein isolated from amyloid tissue (AP). Polyacrylamide gel electrophoresis in SDS reveals a single subunit of 25,000 daltons for both SAP and AP preparations. N-terminal amino acid sequence of this alpha globulin to 13 residues reveals complete homology with the tissue-extracted protein, suggesting that AP is incorporated into, or adsorbed onto, amyloid fibrils without biochemical alteration.

Amino Acid Sequence↗
PubMed1977

Fractionation of primary amyloid fibrils. Characterization and chemical interaction of the subunits.

Amyloid fibrils of kappa origin from a patient with primary amyloidosis are dissociated in various denaturants and fractionated into their subunit components on Sepharose 6B. Solubilization of the fibrils in 4 M guanidine-HCl followed by reduction and alkylation produced 22 000 and 17 000 dalton fractions. Without prior reduction and alkylation, these fractions exist as a high molecular weight protein which can be separated on Sepharose 6B. A high molecular weight protein can be directly dissociated from the amyloid fibril with 1% sodium dodecyl sulfate or 1 M NaCl. Reduction and alkylation of this material produces the two lower molecular weight fractions, i.e., 22 000 and 17 000. These have in the first 20 residues identical N-terminal amino acid sequences; they share immunologic identity and have similar tryptic peptide map profiles. Amino acid analysis of the 22 000 dalton fraction is identical with the intact immunoglobulin light chain isolated from the patient's serum. These data suggest that the insoluble amyloid fibril is the result of aggregation by disulfide linkages between the 22 000 and 17 000 dalton fractions.

Amino Acid Sequence↗