| equivalent focal length | <microscopy> The focal length of the simple lens that has the same power as the compound lens. The stated focal lengths of microscope objectives are the equivalent focal length since their front and back focal lengths are very different. (05 Aug 1998) |
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| focal | Limited to one specific area. (16 Dec 1997) |
| 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) |
| 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 and segmental hyalinosis | <nephrology> A kidney disorder that results in fibrosis and scarring in the kidney glomerulus. The cause is unknown but some cases can result from reflux nephropathy. The clinical manifestation of this kidney disorder is nephrotic syndrome. Symptoms include weight gain, swelling, hypertension and foamy urine. High blood cholesterol and triglyceride levels are also seen with this disorder. Treatment has included the use of corticosteroids and immunosuppressives. Antihypertensive agents and diuretics may also be necessary. Over one-half will develop chronic renal failure within 10 years of diagnosis. (27 Sep 1997) |
| 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) |