| occult | Obscure, concealed from observation, difficult to understand. (18 Nov 1997) |
|---|---|
| occult bleeding | See: occult blood. (05 Mar 2000) |
| occult blood | Blood that is in the faeces or vomitus that is not obvious by general inspection. Used as a diagnostic screening test for colon cancer. Tests for occult blood are generally colourimetric. Stool sample will turn blue when a particular chemical reagent is mixed with the specimen on test paper. Kits for measuring occult blood in the stools are now available at most drug stores. (27 Sep 1997) |
| occult border of nail | The proximal border of the nail entirely covered by the nail wall. Synonym: margo occultus unguis, occult border of nail. (05 Mar 2000) |
| occult carcinoma | <tumour> A small carcinoma, either asymptomatic or giving rise to metastases without symptoms due to the primary carcinoma. (05 Mar 2000) |
| occult fracture | A condition in which there are clinical signs of fracture but no X-ray evidence; after 3 or 4 weeks X-ray imaging shows new bone formation. (05 Mar 2000) |
| occult hydrocephalus | <neurology> A brain disorder caused by blockage of the flow of cerebrospinal fluid (CSF), with enlargement of the ventricles of the brain (keep the pressure normal) and compression of brain tissue. Brain atrophy is the result. In this condition the CSF is produced normally but not reabsorbed. Symptom onset is gradual. A key feature is dementia. Treatment is surgical (VP shunt). (13 Nov 1997) |
| faecal occult blood test | <investigation> A chemical test that measures the presence of fresh or decomposed blood. Blood may arise from bleeding anywhere along the gastrointestinal tract, from the mouth to the anus. An easy to perform colourmetric test. Occult means hidden. (08 Mar 2000) |
| bovine virus diarrhoea virus | A virus of the genus Pestivirus, in the family Togaviridae, causing bovine virus diarrhoea; New York, Oregon, and Indiana strains of the virus are recognised. Synonym: mucosal disease virus. (05 Mar 2000) |
| abelson leukaemia virus | A defective murine leukaemia virus capable of transforming lymphoid cells and producing a rapidly progressing lymphoid leukaemia after superinfection with friend, moloney, or rauscher virus. (12 Dec 1998) |
| Abelson murine leukaemia virus | A retrovirus belonging to the Type C retrovirus group subfamily (family Oncovirinae) which is associated with leukaemia and produces in vitro transformation of mouse cells. (05 Mar 2000) |
| adeno-associated virus | <virology> A genus of viruses in the family Parvoviridae which are all defective viruses (unable to replicate by themselves) and depend on the co-infection of their host cell by other, nondefective viruses to help them replicate. (09 Oct 1997) |
| adenoidal-pharyngeal-conjunctival virus | <virology> An icosahedral (20-sided) virus that contains DNA, there are over 40 different adenovirus varieties, some of which cause the common cold. (10 May 1997) |
| adenosatellite virus | <virology> A genus of viruses in the family Parvoviridae which are all defective viruses (unable to replicate by themselves) and depend on the co-infection of their host cell by other, nondefective viruses to help them replicate. (09 Oct 1997) |
| african horse sickness virus | A species of orbivirus that causes disease in horses, mules, and donkeys. (12 Dec 1998) |