| thyrotoxic complement-fixation factor | A form of thyrotoxin; an antigen found most readily in thyroid tissue from thyrotoxic individuals; known to be chemically and immunologically distinct from thyroglobulin, and fixes complement when combined with antibody related to the gamma-globulin fraction of serum. With the exception of extremely small concentrations, the antigen is rarely found in normal glands or in diseased glands that are not associated with thyrotoxicosis; it is probably an intracellular substance (possibly a constituent of the "microsomal fraction"), and does not contain iodine in significant quantity. Not related to the complement-fixation reaction occurring with serum in Hashimoto's disease, in which the antigen is thyroglobulin. (05 Mar 2000) |
|---|---|
| elastic band fixation | The stabilization of fractured segments of the jaws by means of intermaxillary elastics applied to splints or appliances. (05 Mar 2000) |
| tissue fixation | The technique of using fixatives in the preparation of cytologic, histologic, or pathologic specimens for the purpose of maintaining the existing form and structure of all the constituent elements. (12 Dec 1998) |
| jaw fixation techniques | The stable placement of surgically induced fractures of the mandible or maxilla through the use of elastics, wire ligatures, arch bars, or other splints. It is used often in the cosmetic surgery of retrognathism and prognathism. (12 Dec 1998) |
| external fixation | <orthopaedics> The use of a special metal orthopaedic device (external fixator) to stabilise regions of bone. The majority of this special metal hardware is placed outside of the skin. See: internal fixation. (27 Sep 1997) |
| external pin fixation | In oral surgery, stabilization of fractures of the mandible, maxilla, or zygoma by pins or screws drilled into the bony part through the overlying skin and connected by a metal bar. Pin fixation by replacing the rigid metal bar connector with an acrylic bar adapted at the time of reduction of the fracture. (05 Mar 2000) |
| field of fixation | In ophthalmology, the angular distance around which the line of fixation can be turned. (05 Mar 2000) |
| fixation | 1. <orthopaedics> The act or operation of holding, suturing or fastening in a fixed position. The condition of being held in a fixed position. 2. <psychiatry> A term with two related but distinct meanings: 1. Arrest of development at a particular stage, which like regression (return to an earlier stage), if temporary is a normal reaction to setbacks and difficulties but if protracted or frequent is a cause of developmental failures and emotional problems. 3. <psychology> A close and suffocating attachment to another person, especially a childhood figure, such as one's mother or father. Both meanings are derived from psychoanalytic theory and refer to fixation of libidinal energy either in a specific erogenous zone, hence fixation at the oral, anal or phallic stage or in a specific object, hence mother or father fixation. 4. <technique> The use of a fixative to preserve histological or cytological specimens. 5. <chemistry> The process whereby a substance is removed from the gaseous or solution phase and localised, as in carbon dioxide fixation or nitrogen fixation. 6. <ophthalmology> The direction of the gaze so that the visual image of the object falls on the fovea centralis. 7. <chemistry> In film processing, the chemical removal of all undeveloped salts of the film emulsion, leaving only the developed silver to form a permanent image. 8. <zoology> A general term for determination of type, whether by designation, or indication. Origin: L. Fixatio (09 Jan 1998) |
| fixation disparity | The amount of heterophoria possible with fusion present. (05 Mar 2000) |
| fixation nystagmus | Nystagmus aggravated or induced by ocular fixation, arising as optokinetic nystagmus, or resulting from midbrain lesions. (05 Mar 2000) |
| fixation, ocular | The direction of the gaze so that the visual image of the object falls on the fovea centralis of the retina, the area of the most acute vision. (12 Dec 1998) |
| fixation reaction | <immunology> Binding of complement as a result of its interaction with immune complexes (the classical pathway) or particular surfaces (alternative pathway). (18 Nov 1997) |
| latex fixation test | A passive agglutination test in which antigen is adsorbed onto latex particles which then clump in the presence of antibody specific for the adsorbed antigen. Synonym: latex fixation test. (05 Mar 2000) |
| latex fixation tests | Passive agglutination tests in which antigen is adsorbed onto latex particles which then clump in the presence of antibody specific for the adsorbed antigen. (12 Dec 1998) |
| line of fixation | A line joining the object (or point of fixation) with the fovea. (05 Mar 2000) |