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At least 19 recordsLinked to original sources
PubMed1971

Chemical classes of amyloid substance.

Concentrates of amyloid substance derived from organs of 10 human patients representing a variety of clinical entities were characterized according to their amino acid compositions, their electrophoretic constituents mobile in urea-starch gel at pH 3 and their stability with respect to the binding of Congo red in the pH interval 9-12.5. The analyses revealed the existence of two major classes of amyloid substance. Material from one class, embracing those cases that had a chronic inflammatory disease as the principal associated process (type A amyloidosis), had a similar amino acid composition and was distinguished by the presence in the amyloid substance of a large amount of an electrophoretically well-defined group of low-molecular-weight proteins with an unusual amino acid composition (amyloid protein A); type A amyloid substance lost the typical binding of Congo red dye at pH 11.5 or lower. Concentrates of amyloid substance in the other class (type B amyloidosis), represented by a case of multiple myeloma, 3 other cases of neoplastic disease and a case of primary cardiac amyloidosis, were distinguished by the presence of an electrophoretically more heterogeneous group of protein constituents with different mobilities and with apparently higher molecular weights than that of protein A, by an amino acid composition that is clearly different from that of the first class, and by retention of the typical Congo red-binding property at pH 12 or higher. The major constituent, protein A, of amyloid substances of the first class is clearly different from ordinary fragments of immunoglobulins in size, electrophoretic mobility, and amino acid composition.

Adult↗
PubMed1979

The amyloid P-component (protein AP): an integral part of the amyloid substance?

The P-component of amyloid (protein AP) appears to be present in all types of amyloid substance regardless of the clinical category of amyloidosis or the chemical class of the amyloid fibril. The role of protein AP in the formation of amyloid substance has not been established. In a patient with primary amyloidosis, significant amounts of protein AP were found closely associated with the amyloid fibril proteins and was released from the latter only after dissociation and reduction of the amyloid fibril preparation. EDTA seemed to be very effective in releasing protein AP, and it is thought that the close association between the amyloid fibrils and protein AP is calcium-dependent. The very close association between the amyloid fibrils and protein AP suggests that the latter is an integral part of the amyloid substance.

Amino Acid Sequence↗
PubMed1994

[Alzheimer disease. Role of beta A4 peptide and cerebral amyloid substance].

Deposition of large quantities of amyloid substance in the walls of the cerebral vessels and in the core of the senile plaques is characteristic of Alzheimer's disease. beta A4 peptide, the main component of the amyloid substance, is a product of a larger amyloid precursor protein which has the structure of a transmembrane receptor and is widely distributed throughout the body. The pathway leading to beta A4 is not yet fully established but could involve lysosomal degradation. It has been suggested that the beta A4 peptide is of neuronal or vascular origin. The beta A4 peptide is found in diffuse deposits in the cortex and cerebellum as well as in the basal ganglia before the classic senile plaques appear, mainly in layer III of the cerebral cortex. These diffuse deposits are devoid of degenerating neurites (i.e. containing abnormally phosphorylated tau protein). The classical senile plaques contain numerous degenerating neurites linking them to the connective network of the cortex. The intellectual deficit is correlated significantly to the density of the classical senile plaques but not to the density of the diffuse deposits. Although a mutation of the gene coding for the beta A4 peptide appears to be sufficient to induce (or accelerate) Alzheimer's disease, this is undoubtedly an exceptional mechanism. Certain mutations involving the beta A4 precursor protein gene increase in vitro the production of beta A4. The molecular and morphological steps leading, from the accumulation of the peptide (which in itself has no clinical expression) to the neurofibrillary pathology of the senile plaques and of the neurones (which are strongly correlated with clinical dementia), remain hypothetical.

Aged↗
PubMed1977

Histochemistry of the amyloid substance from familial amyloidotic polyneuropathy.

The histochemical properties of the amyloid substance from familial amyloidotic polyneuropathy (FAP) were studied. The results showed differences among the FAP amyloid and the others amyloid substance. The main difference being that FAP amyloid substance was free of or only contain a small amount of protein. It contains acid and neutral glycidic substances, constituting its major part.

Amyloid↗
PubMed1987

Transformation of degenerating neurofibrils into amyloid substance in Alzheimer's disease: histochemical and immunohistochemical studies.

Degenerating neurofibrils (DNF), which are composed of paired helical filaments (PHF) and amyloid fibrils (AF), are the 2 characteristic pathological fibrillar deposits in Alzheimer cortex. These fibrils were simultaneously studied by 2 techniques: The immunolabelling with a specific antiserum raised against PHF and elective thioflavine S staining of AF. In neuronal perikaryons, neurofibrillary tangles (NFT) consist of 3 populations: firstly, strongly immunolabelled tangles were weakly thioflavine-stained. Secondly, less dense tangles were weakly immunolabelled but strongly thioflavine-stained. Thirdly, ghost tangles which correspond to extracellular NFT were exclusively thioflavine-stained. Thus, it is likely that NFT are degraded to form extracellular AF. Around neuritic plaques and some vessels with amyloid angiopathy, immunolabelled neurites, thioflavine-stained neurites and transition figures were also observed. On the other hand, the central core of plaques and pathological vessel walls were strongly thioflavine-stained but were never immunoreactive. In conclusion, these observations favour catabolism of PHF bundles found in NFT and in degenerating neurites into an amyloid substance. This amyloid substance seems different from other amyloid deposits found in the central core of neuritic plaques and vessel walls.

Aged↗
PubMed1993

Bleeding tendency caused by the deposit of amyloid substance in the perivascular region.

A 55-year-old woman, who had systemic amyloidosis associated with multiple myeloma, had sudden development of hematomas of her lip and upper eye lid. There was no evidence of deterioration of multiple myeloma, thrombocytopenia nor deficiency of coagulation factors. Biopsy specimen showed the deposit of amyloid substance in the dermis and perivascular region. The bleeding tendency in this patient with myeloma was likely due to the deposit of amyloid substance in the vascular wall; improvement was achieved with administration of hemostatic agents.

Adrenochrome↗
PubMed1980

[Amyloidosis. I. Recent findings concerning amyloid substance].

The considerable progress made recently in the study of amyloid substance have led to the identification of numerous organised protein components in typical microfibrillar structures. In spite of the biochemical heterogeneity of fibril proteins, it is still possible to find similar chemicophysical and tintorial features in the various types of amyloid, probably due, at least in part, to the common Beta type molecular configuration, a structure proper to fibril proteins. In so-called primary amyloidosis and in that associated with myelomatous diseases, the principal protein component consists of AL protein, correlated with the light immunoglobulin chains, with which analogies have been observed both in the amino acid sequence and in antigenic characteristics. In secondary amyloidosis, AA protein, which is unrelated to immunoglobulins or other known human proteins, is prevalent. AA protein probably derives from a serum globulin, SAA, whose blood levels increase during numerous pathological processes, particularly in those of neoplastic or inflammatory type. The origin of serum protein, which might be either a normal tissue component released under stimulus or a reagent of the acute phase synthesised ex novo, and its function, which is probably of immunomodulator or more specifically immunosuppressive type, are still to be defined. In all forms of amyloidosis studied, a common observation is the presence of AP protein, organised in pentagonal structures. This protein would appear to derive from a serum component defined as SAP, with a marked affinity for amyloid fibrils. Also identifiable are other forms of amyloid such as APUD-amyloid, which probably derives from polypeptide hormones, and AS amyloid, which is present in some organs of elderly patients and is biochemically identifiable at cardiac level with A(SCA) protein. Still awaiting definition in amyloid tumours or amyloidomas is the precise chemical composition of deposited proteins.

Amyloid↗
PubMed1979

Senile cardiac amyloidosis: evidence of two different amyloid substances in the ageing heart.

In a material of seventy-two persons over 70 years of age, forty-seven cases of amyloidosis of the heart were found. In thirty-nine cases, deposits occurred only in the atria (isolated artrial amyloidosis, IAA), while in eight cases amyloid also was seen in the ventricles (senile cardiac amyloidosis, SCA). In some of the latter cases, small amyloid deposits occurred in other organs, especially the lungs. Some definite differences existed between the amyloid substance in SCA and IAA. Thus, tryptophan was demonstrated histochemically in SCA but not in IAA, and, furthermore, amyloid fibrils isolated from patients with IAA lacked protein Asca, the fibril subunit protein of senile cardiac amyloid. It is concluded that the ageing heart may be the target of two different forms of amyloid, one only affecting the atria, while the other is more widespread within the heart and sometimes also is found in other organs.

Aged↗
PubMed1983

Fluorescent staining of nuclei and amyloid substance. Two useful properties of p-phenylenediamine.

Mounting immunofluorescent slides in an oxidized solution of p-phenylenediamine in 90% glycerol, resulted in brown fluorescent staining of nuclei. This contrasts well with the fluorescence of fluorescein and rhodamine conjugates and facilitates excellent morphological localization of antigens. The antifading effect of p-phenylenediamine is maintained in this oxidized solution. In addition, amyloid substance gives a bright yellow-orange fluorescence with this medium. This method of staining is more sensitive and less time consuming than the usual methods for amyloid. Alternative techniques to keep the antifading effect without either nuclear or amyloid counterstain (for identification of nuclear antigens), or to show up amyloid deposits without nuclear counterstain (for small amyloid deposits) are described.

Amyloid↗
PubMed1983

Epidermoid carcinoma arising in parotid adenolymphomatous lesion with microdeposit of amyloid substance.

A case of an epidermoid carcinoma which arose in a cystic adenolymphoma-like lesion of the parotid gland is presented. Histologically, in the major part, the tumor tissue showed a papillary cystadenoma lymphomatosum-like pattern with the stroma consisting of mainly plasma cells and lymphocytes, but the epithelial element was mostly multilayered, showing a keratinous differentiation. In some areas, sebaceous-like cells and oxyphilic cells were found in the epithelial component. In the surrounding fibrous tissue, the invasive growth of the epithelial cells could be observed. Microdeposit of amyloid substance was found in the lymphoid stromal tissue and also in the intercellular space of the epithelial element. A mass of epithelioid cells and cholesterol crystal clefts were observed in the granulomatous tissue which proliferated around the tumor tissues. About 4 months after surgical excision, a recurrent tumor, which was well differentiated squamous cell carcinoma, appeared on the same site as the primary tumor.

Adenolymphoma↗