| disc sequestration | <radiology> Complete separation of disc material with rupture through posterior longitudinal ligament into the epidural space; free fragment herniation findings: migration superiorly/inferiorly with compression of nerve roots above/below the level of herniation, disc material noted more than 9mm from disc space Differential diagnosis: postoperative scarring (retraction of thecal sac to the site of surgery), epidural abscess/tumour, conjoined nerve root: 2 nerve roots arising simultaneously from the thecal sac; normal variant in 1-3% see: degenerative disc disease (12 Dec 1998) |
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| imaginal disc | Epithelial infoldings in the larvae of holometabolous insects (e.g. Lepidoptera, Diptera) that rapidly develop into adult appendages (legs, antennae, wings etc.) during metamorphosis from larval to adult form. By implanting discs into the haemocoele of an adult insect their differentiation can be blocked, though their determination remains unchanged except occasionally (transdetermination). The hierarchy of transdetermination has been studied in great detail in Drosophila. (11 Mar 1998) |
| intercalated disc | An electron dense junctional complex, at the end to end contacts of cardiac muscle cells, that contains gap junctions and desmosomes. most of the disc is formed of a convoluted fascia adherens type of junction into which the actin filaments of the terminal sarcomeres insert (they are therefore equivalent to half Z bands), desmosomes are also present. The lateral portion of the stepped disc contains gap junctions that couple the cells electrically and thus coordinate the contraction. (18 Nov 1997) |
| interpubic disc | The disk of fibrocartilage that unites the pubic bones at the pubic symphysis. Synonym: discus interpubicus, interpubic disk, lamina fibrocartilaginea interpubica. (05 Mar 2000) |
| tilting disc valve | A variety of prosthetic cardiac valve composed of one or two discs within a retaining device. (05 Mar 2000) |
| tilting disc valve prosthesis | A low profile artificial heart valve with excellent flow characteristics. (05 Mar 2000) |
| electrophoresis, disc | Electrophoresis in which discontinuities in both the voltage and pH gradients are introduced by using buffers of different composition and pH in the different parts of the gel column. The term 'disc' was originally used as an abbreviation for 'discontinuous' referring to the buffers employed, and does not have anything to do with the shape of the separated zones. (12 Dec 1998) |
| excavation of optic disc | The normally occurring depression or pit in the centre of the optic disc. Synonym: excavatio disci, depression of optic disk, excavatio papillae, physiologic cup, physiologic excavation. (05 Mar 2000) |
| Z disc | <cell biology> Region of the sarcomere into which thin filaments are inserted. Location of _ actinin in the sarcomere. (18 Nov 1997) |
| agonal infection | An acute infection, commonly pneumonic or septic, occurring toward the end of any disease and often the cause of death. Synonym: agonal infection. (05 Mar 2000) |
| airborne infection | A mechanism of transmission of an infectious agent by particles, dust, or droplet nuclei suspended in the air. (05 Mar 2000) |
| apical infection | Implantation of microorganisms at the apex of a tooth, usually the result of the migration of microorganisms from the pulp canal through the apical foramen. (05 Mar 2000) |
| arbovirus infection | <virology> A type of viral infection that is transmitted by mosquitoes in late spring to early autumn. One manifestation is encephalitis (central nervous system infection). (27 Sep 1997) |
| ascariasis infection | <microbiology> Infection by the nematode Ascaris lumbricoides and is characterised by an early pulmonary phase related to larval migration and a later, prolonged intestinal phase. Adult worms are 15-40 cm in length and maintain themselves in the lumen of the small intestine. Infection occurs after ingesting eggs contained in contaminated food or more commonly, by transmission to the mouth by the hands after contact with contaminated soil. Treatment is with mebendazole or pyrantel pamoate. (27 Sep 1997) |
| atypical mycobacterial infection | <microbiology> Infection with organisms from the Mycobacterium genus other than tuberculosis. Risk factors include immunocompromised patients and those with AIDS. Mycobacterium avium intracellulare is an example which frequently infects AIDS patients. Atypical mycobacterial infections can cause abscesses, septic arthritis and osteomyelitis. Treatment can be difficult due to the emergence of resistance to standard antitubercular antibiotics. (27 Sep 1997) |