| collagen | <protein> The protein substance of the white fibres (collagenous fibres) of skin, tendon, bone, cartilage and all other connective tissue, composed of molecules of tropocollagen, it is converted into gelatin by boiling. Collagenous pertaining to collagen, forming or producing collagen. Origin: Gr. Kolla = glue, gennan = to produce (18 Nov 1997) |
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| collagen diseases | Historically, a heterogeneous group of acute and chronic diseases, including rheumatoid arthritis, systemic lupus erythematosus, progressive systemic sclerosis, dermatomyositis, etc. This classification was based on the notion that "collagen" was equivalent to "connective tissue", but with the present recognition of the different types of collagen and the aggregates derived from them as distinct entities, the term "collagen diseases" now pertains exclusively to those inherited conditions in which the primary defect is at the gene level and affects collagen biosynthesis, post-translational modification, or extracellular processing directly. (12 Dec 1998) |
| collagen fibre | An individual fibre that varies in diameter from less than 1 um to about 12 um and is composed of fibrils; the fibre's, which are usually arranged in bundles, undergo some branching and are of indefinite length; chemically the fibre is a glycoprotein, collagen, which yields gelatin upon boiling; they make up the principal element of irregular connective tissue, tendons, aponeuroses, and most ligaments, and occur in the matrix of cartilage and osseous tissue. Synonym: white fibre. (05 Mar 2000) |
| collagen fibrils | The fibril's that comprise a collagen fibre, ranging from 20 to 200 nm and averaging about 100 nm in diameter (substantially larger in tendons), with cross-striations averaging 64 nm. Synonym: collagen fibrils. (05 Mar 2000) |
| collagen injection | Correction of superficial soft tissue deformities, acne scars, or age-related skin changes by injection (implantation) of collagen; bovine collagen preparations are commonly used. Prior intradermal testing is necessary to exclude hypersensitivity. (05 Mar 2000) |
| collagen telopeptidase | <enzyme> Neutral metalloproteinase from porcine gingiva; removes the extra-helical extension peptides proximal to the lysyl residue at position 17 Registry number: EC 3.4.24.- Synonym: collagen depolymerase (26 Jun 1999) |
| collagen-vascular diseases | A group of generalised disease's affecting connective tissue and frequently characterised by fibrinoid necrosis or vasculitis; in some collagen disease's, auto-immunization, particularly antinuclear antibodies, has been shown and circulating immune complexes are found. The term is not entirely acceptable because there is no evidence that collagen is primarily involved; "collagen" was once synonymous with "connective tissue" rather than describing a specific fibrinous protein in that tissue. See: connective-tissue diseases. (05 Mar 2000) |
| SLS collagen | <protein> Abnormal packing pattern of collagen molecules formed if ATP is added to acidic collagen solutions, in which lateral aggregates of molecules are produced. Each aggregate is 300 nm long and the molecules are all in register. If SLS aggregates are overlapped with a quarter stagger, the 67 nm banding pattern of normal fibrils is reconstituted. (19 Jan 1998) |
| acrocephalosyndactyly type 1 | <paediatrics> An inherited disease (autosomal dominant) or a spontaneously occurring disease characterised by a peaked head and unusual facial appearance, due to the premature closure of the cranial sutures. A skull X-ray can confirm the diagnosis and treatment is surgical. Inheritance: autosomal dominant. (27 Sep 1997) |
| Alzheimer type I astrocyte | Enlarged frequently multinucleated astrocytes, seen in progressive multifocal leukoencephalopathy. (05 Mar 2000) |
| Alzheimer type II astrocyte | Enlarged astrocytes with vesicular nuclei and one or more small basophilic nucleoli, seen in hepatocerebral disease and Wilson's disease. (05 Mar 2000) |
| American Type Culture Collection | <cell culture> A key resource for cultured cells, located in Rockville, USA. (12 Dec 1998) |
| Antoni type A neurilemoma | <tumour> Relatively solid or compact arrangement of neoplastic tissue that consists of Schwann cells arranged in twisting bundles and associated with delicate reticulin fibres; the nuclei of the Schwann cells are frequently grouped in parallel rows (so-called palisades), and the nuclei and fibres sometimes form exaggerated tactile corpuscles, called Verocay bodies. (05 Mar 2000) |
| Antoni type B neurilemoma | <tumour> Relatively soft or loose arrangement of neoplastic tissue that consists of Schwann cells in a haphazard or nondescript type of arrangement among reticulin fibres and tiny cystlike foci; fat-laden macrophages may be observed in some of the larger neoplasms. (05 Mar 2000) |
| arthus-type reaction's | Reaction's in man and other species that result from the same basic immunologic (allergic) mechanism which evokes, in the rabbit, the typical Arthus phenomenon. See: immune complex disease. (05 Mar 2000) |