amyloid

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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 ?
Instead of suspending the individual amyloids in a carrier fluid like a water jet the scientists placed it on an ultrathin solid carrier made of graphene, in which carbon atoms are arranged in a hexagonal pattern rather like an atomic honeycomb.
This method allows diffraction patterns to be obtained from fewer than 50 amyloid fibrils, so that the structural differences emerge more clearly.
'In our study, we wanted to know if excessive daytime sleepiness causes an increase of amyloid over time in people without dementia,' Vemuri continued.
A newly designed membrane uses thin amyloid protein fibers to pull heavy metals and radioactive wastes out of water.
The team converted milk proteins into fibers of durable amyloid protein.
In the pore hypothesis, amyloid species can interact with the membrane surface and oligomerize to form localized pores or channels that cause an uncontrolled, nonphysiological flux of ions across the membrane [9, 10, 14].
The finding of the research suggests that amyloids could have been the solver of the nature's early enzyme problem.
The biosensor works by producing an electrical signal on detecting amyloid clusters in the blood.
Amyloid is a pathologic protein substance that is deposited between cells in various tissues and organs of the body.
IAPP has been found in all mammals studied to date and the sequence is strongly conserved although there are interspecies variations and these correlate with the ability to form amyloid in vivo (Figure 1).
The concurrent discovery that a mutation in the amyloid precursor protein (APP) gene caused early-onset Alzheimer's, coupled with the association of plaque deposition and early Alzheimer's in Down syndrome patients, added weight to the theory (Trends Pharmicol.
It is currently believed that this type of experimental amyloidosis is due to the abnormal production and degradation of serum amyloid A protein (SAA).[3] Although SAA is a major acute phase reactant, its physiological role is unknown.