Akademik

1. A plate, film, or tape holder for use in photography or radiography. A radiographic c. contains two intensifying screens and a sheet of x-ray film. 2. A perforated holder in which tissue blocks are placed for paraffin embedding. [Fr., dim. of casse, box]

- susceptibility c. a common sequence of amino acid s in residues 70–74 in the HLA-DRB1 chains, found in alleles associated with rheumatoid arthritis. It is one of two variations: glutamine[Q]-lysine[K]-arginine[R]-alanine[A]-alanine[A] or QRRAA. These susceptibility cassettes are found in many different DRB1 alleles. The alpha and beta chains that form these antigen-presenting molecules have a configuration not unlike a trough or rain gutter; antigens are bound by sequences of amino acid s in a pocket along the bottom and sides of the trough or cavity, and this complex forms a heterotrimer with the T-cell receptor on CD4+ cells. SYN: rheumatoid pocket, shared epitope.

cas·sette also ca·sette kə-'set, ka- n

1) a lightproof magazine for holding film or plates for use in a camera specif one for holding the intensifying screens and film in X-ray photography

2) a small plastic cartridge containing magnetic tape with the tape on one reel passing to the other

(in radiography) a thin light-proof box in which a piece of photographic film is placed. It usually contains special screens, which fluoresce on exposure to X-rays, intensifying the image formed on photographic film when a radiographic exposure is taken. In computerized radiography the cassette may contain an electrically charged plate.