amyloid

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Related to Amyloid protein: Tau protein, Amyloid precursor protein

amyloid

 [am´ĭ-loid]
1. resembling starch; characterized by starchlike staining properties.
2. the pathologic extracellular proteinaceous substance deposited in amyloidosis; it is a waxy eosinophilic material. Amyloid deposits are composed primarily of straight, nonbranching fibrils arranged either in bundles or in a feltlike meshwork; each fibril is composed of identical polypeptide chains in stacked sheets. There are two major biochemical types of amyloid protein: amyloid light chain protein and amyloid A protein, as well as others seen less often.

am·y·loid

(am'i-loyd),
1. Any of a group of chemically diverse proteins that appear microscopically homogeneous but are composed of linear nonbranching aggregated fibrils arranged in sheets when seen under the electron microscope; amyloid stains dark brown with iodine, produces a characteristic green birefringence in polarized light after staining with Congo red, is metachromatic with either methyl violet (pink-red) or crystal violet (purple-red), and fluoresces yellow after thioflavine T staining.
2. The pathologic extracellular proteinaceous substance deposited in amyloidosis. There are two major types of amyloid protein: amyloid light chain protein that occurs in primary amyloidosis and amyloid, a protein that occurs in reactive systemic amyloidosis.
3. Resembling or containing starch.
[amylo- + G. eidos, resemblance]

amyloid

(ăm′ə-loid′)
n.
1. A starchlike substance.
2.
a. An insoluble, fibrous structure consisting chiefly of an aggregation of proteins arranged in beta sheets, forming extracellular deposits in organs or tissues and characteristic of certain diseases such as Alzheimer's disease and Parkinson's disease.
b. The substance that makes up such a structure.
adj.
1. Starchlike.
2. Being or related to proteinaceous amyloid: amyloid plaque.

amyloid

β-fibrillosis A homogeneous, extracellular glycoprotein with a fibrillary ultrastructure, derived either from
1. The N-terminal of lambda or kappa Ig light chains–amyloid of immune origin, a 5-18 kD glycoprotein produced by a single clone of plasma cells or.
2. Amyloid of unknown origin, from serum amyloid A–SAA, an acute phase protein that ↑ sharply during inflammation; all amyloids have a common molecular theme, that of the β-pleated protein sheet, demonstrable by X-ray crystallography and responsible for amyloid's Congo red staining and resistance to proteolytic digestion See Beta amyloid. Cf Alzhemier's disease.

am·y·loid

(am'i-loyd)
1. Any of a group of chemically diverse proteins that appears microscopically homogeneous but is composed of linear nonbranching aggregated fibrils arranged in sheets when seen under the electron microscope; it stains dark brown with iodine, produces a characteristic green color in polarized light after staining with Congo red, is metachromatic with either methyl violet (pink-red) or crystal violet (purple-red), and fluoresces yellow after thioflavine T staining; amyloid occurs characteristically as pathologic extracellular deposits (amyloidosis), especially in association with reticuloendothelial tissue; the chemical nature of the proteinaceous fibrils is dependent on the underlying disease process.
2. Resembling or containing starch.
[amylo- + G. eidos, resemblance]

amyloid

One of a range of proteins deposited in the brain in spongiform encephalopathies such as CREUTZFELDT-JAKOB DISEASE, in other degenerative brain disorders such as ALZHEIMER'S DISEASE, and in the tissues in a wide range of long-term suppurative disorders (see AMYLOIDOSIS). It is a hard, waxy proteinaceous substance in the form of straight, rigid, non-branching fibrils, 10–15 nm in diameter that are insoluble in water and relatively resistant to breakdown by proteolytic enzymes. There is a considerable range of amyloid proteins mainly specific for the different conditions in which amyloid is deposited. From the Latin amylum , starch.

Amyloid

Amyloid protein resembles a starch and is deposited in tissues during the course of certain chronic diseases.

am·y·loid

(am'i-loyd)
Any of a group of chemically diverse proteins that appears microscopically homogeneous but is composed of linear nonbranching aggregated fibrils arranged in sheets when seen under the electron microscope; occurs characteristically as pathologic extracellular deposits (amyloidosis), especially in association with reticuloendothelial tissue; the chemical nature of the proteinaceous fibrils, depends on the underlying disease process.
[amylo- + G. eidos, resemblance]
References in periodicals archive ?
Bexarotene, currently used to treat non-Hodgkin lymphoma has been investigated by researchers at the University of Cambridge and has been shown to interfere with the development of amyloid protein in worms, if given in the very early stages of the amyloid plaque formation.
We observed conformational changes especially at the N-and C-terminal regions of beta amyloid protein upon binding to the receptor.
Renal amyloidosis with a frame shift mutation in fibrinogen alpha-chain gene producing a novel amyloid protein. Blood.
The amyloid protein inflicts damage by interacting with an enzyme called Amyloid Beta Alcohol Dehydrogenase (ABAD) and releasing toxic substances which kill brain cells.
Biopsy the affected organ * Congo red binding and green birefringence under polarized light * Fibril structure on electron microscopy * X-ray crystallography and infrared spectroscopy to confirm the characteristic cross beta-pleated sheet * Biochemical and/or immunohistochemical identification of the major amyloid protein * For patients with the AL type of amyloid: Immunohistochemical staining: demonstration of kappa and lambda chains in plasma cells Molecular genetic methods: differentiation between poly- and monoclonal B cells Step 2.
The process leads to making defective beta amyloid protein which is an iconic symptom in Alzheimer's disease.
Professor Jerry Turnbull, from the university's Institute of Integrative Biology, said: "We are targeting an enzyme, called BACE, which is responsible for creating the amyloid protein.
These target the accumulation of beta amyloid protein deposits in the brain which are a key feature of Alzheimer's.
Emphasizing the diversity of peptide systems, membrane assemblies, and biological phenomena investigated using in vitro and in vivo research studies in the past few years, this book surveys the latest progress in understanding the role of lipids and membranes in the formation of amyloid protein deposits.
Doctors can use a PET scan to monitor the build-up of beta amyloid protein deposits in the brain, a key feature of Alzheimer's.
Genetics may be associated with amyloidosis in several ways: either as a mutation in nonamyloid protein or as a mutation involving amyloid protein itself; a potential role for genetics in "sporadic amyloidoses" is also suspected.
Although the exact cause of Alzheimer's disease is not completely understood, experts have recently identified one mechanism involving the insufficient breakdown and recycling of amyloid protein in the brain.