D factor
| focal adhesion | <cell biology> Areas of close apposition and thus presumably anchorage points, of the plasma membrane of a fibroblast (for example) to the substratum over which it is moving. Usually 1m x 0.2 m with the long axis parallel to the direction of movement, always associated with a cytoplasmic microfilament bundle that is attached via several proteins to the plasma membrane at an area of high protein concentration (this is noticeably electron dense in electron micrographs). Focal adhesions tend to be characteristic of slow moving cells. (18 Nov 1997) |
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| focal amyloidosis | A localised form of amyloidosis in which amyloid occurs as masses or nodules beneath the skin or mucous membranes, e.g., in the larynx. Synonym: amyloid tumour, focal amyloidosis. (05 Mar 2000) |
| focal appendicitis | Acute appendicitis involving only part of the appendix, sometimes at the site of, or distal to, an obstruction of the lumen. (05 Mar 2000) |
| focal condensing osteitis | A reaction of bone to a mild bacterial infection, often the result of a carious tooth, in persons with a high degree of tissue resistance; results in a localised radio-opacity. Synonym: focal condensing osteitis. (05 Mar 2000) |
| focal depth | Depth of focus, the greatest distance through which an object point can be moved while maintaining a clear image. Synonym: penetration. (05 Mar 2000) |
| focal dermal hypoplasia | A genetic skin disease characterised by hypoplasia of the dermis, herniations of fat, and hand anomalies. It is found exclusively in females and transmitted as an x-linked dominant trait. (12 Dec 1998) |
| focal distance | The distance from the centre of a lens to its focus. (05 Mar 2000) |
| focal embolic glomerulonephritis | Glomerulonephritis associated with subacute bacterial endocarditis, frequently producing microscopic haematuria without azotemia. (05 Mar 2000) |
| focal epilepsy | Epilepsy of various aetiologies characterised by focal seizures or secondarily generalised tonic-clonic seizures. Ictal symptoms are often related to the brain region where the seizure begins focally. Synonym: cortical epilepsy, local epilepsy, partial epilepsy. (05 Mar 2000) |
| focal epithelial hyperplasia | Hyperplasia of the mucous membrane of the lips, tongue, and less commonly, the buccal mucosa, floor of the mouth, and palate, presenting soft, painless, round to oval sessile papules about 1 to 4 mm in diameter. The condition usually occurs in children and young adults and has familial predilection, lasting for several months, sometimes years, before running its course. A viral aetiology is suspected, the isolated organism being usually the human papilloma virus. (12 Dec 1998) |
| focal gallbladder wall thickening | <radiology> Primary gall bladder carcinoma, adenomyomatosis / hyperplastic cholecystosis, adenomatous polyps, papillary adenomas, metastatic nodules, cholesterol polyps (associated with acoustic shadowing), metachromatic leukodystrophy (rare!) See also: diffuse thickening (12 Dec 1998) |
| focal gigantism | <radiology> Neurofibromatosis, AVM, Klippel-Trenaunay-Weber syndrome, Beckwith-Wiedemann syndrome, Parks-Davis syndrome, haemangioma, JRA (12 Dec 1998) |
| focal glomerulonephritis | Glomerulonephritis affecting a small proportion of renal glomeruli which commonly presents with haematuria and may be associated with acute upper respiratory infection in young males, not usually due to streptococci; associated with IgA deposits in the glomerular mesangium and may also be associated with systemic disease, as in Henoch-Schonlein purpura. Synonym: Berger's disease, Berger's focal glomerulonephritis, focal nephritis, IgA nephropathy. (05 Mar 2000) |
| focal illumination | Illumination in which a beam of light is directed diagonally to an object so that it is brilliantly illuminated while the surrounding area is in shadow. Synonym: lateral illumination, oblique illumination. Kohler illumination, a method of illumination of microscopic objects in which the image of the light source is focused on the substage condenser diaphragm and the diaphragm of the light source is focused in the same plane with the object to be observed; maximises both the brightness and uniformity of the illuminated field. (05 Mar 2000) |
| focal infection | An old term which distinguishes local infection's (focal) from generalised infection's (sepsis). (05 Mar 2000) |