| 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) |
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| 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 interval | The distance between the anterior and posterior focal points of the eye. (05 Mar 2000) |
| focal length | <microscopy> The distance from the optical centre of the lens to the focal point<microscopy> The focal length of an objective and its working distance are directly proportional. (05 Aug 1998) |
| focal lymphocytic thyroiditis | Focal infiltration of the thyroid by lymphocytes and plasma cells. See: Hashimoto's thyroiditis. (05 Mar 2000) |
| focal metastatic disease | Presence of a single area of metastasis of a malignant tumour or infection distant from the primary lesion. (05 Mar 2000) |
| focal motor seizure | A simple partial seizure with localised motor activity. (05 Mar 2000) |
| focal necrosis | Occurrence of numerous, relatively small or tiny, fairly well-circumscribed, usually spheroidal portions of tissue that manifest coagulative, caseous, or gummatous necrosis and are characteristically associated with agents that are haematogenously disseminated; frequently observed only in histologic sections, but the foci may be as large as 1 to 3 mm and macroscopically visible; arbitrarily, foci larger than that are usually not termed focal necrosis. (05 Mar 2000) |
| focal nephritis | 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 nodular hyperplasia | <radiology> Focal nodules of normal hepatocytes, Kuppfer cells and bile ducts, F more than M, rare, benign, multiple in 20%, haemorrhage (most common complication) in only 2-3% (unlike hepatic adenoma), stellate fibrous septae (stellate scar), NM: normal or increased uptake on HIDA and sulfur colloid (12 Dec 1998) |
| focal point | Location of an organism, for fish, usually the position of the snout. Habitat measurements made at that position (depth, water velocity, etc.) are focal point measurements. (09 Oct 1997) |
| focal reaction | A reaction which occurs at the point of entrance of an infecting organism or of an injection, as in the Arthus phenomenon. Synonym: local reaction. (05 Mar 2000) |
| focal sclerosing glomerulopathy | Focal, segmental glomerulosclerosis reported in adults and children with normal serum complement, progressing to chronic glomerulonephritis. (05 Mar 2000) |
| focal sclerosis | <neurology> Neurodegenerative disease characterised by the gradual accumulation of focal plaques of demyelination particularly in the periventricular areas of the brain. Peripheral nerves are not affected. Onset usually in 3rd or 4th decade with intermittent progression over an extended period. Cause still uncertain. (18 Nov 1997) |
| focal sclerosis with 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) |