| APUD cell | <pathology> A group of apparently unrelated endocrine cells found throughout the body which have a number of similar characteristics and which make a number of hormones with similar structures (including serotonin, epinephrine, dopamine, neurotensin, and norepinephrine. See: Amine Precursor Uptake and Decarboxylation. (10 Jan 1998) |
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| argentaffin cell | So called because they will form cytoplasmic deposits of metallic silver from silver salts. Their characteristic histochemical behaviour arises from 5 HT, which they secrete. Found chiefly in the epithelium of the gastrointestinal tract (though possibly of neural crest origin) their function is rather obscure, although there is a widely distributed family of such paracrine (local endocrine) cells (APUD cells). (18 Nov 1997) |
| argyrophilic cell | <pathology> Cell's that bind silver salts but that precipitate silver only in the presence of a reducing agent. See: enteroendocrine cells. (05 Mar 2000) |
| Aschoff cell | A large cell component of rheumatic nodules in the myocardium with a characteristic nucleus and relatively little cytoplasm. (05 Mar 2000) |
| Askanazy cell | <pathology> Abnormal thyroid epithelial cells found in auto immune thyroiditis. The cubical cells line small acini and have eosinophilic granular cytoplasm and often bizarre nuclear morphology. Synonym: Hurthle cell, oxyphil cell, oncocyte. (18 Nov 1997) |
| astroglia cell | <pathology> A glial cell found in vertebrate brain, named for its characteristic star like shape. Astrocytes lend both mechanical and metabolic support for neurons, regulating the environment in which they function. See: oligodendrocytes. (18 Nov 1997) |
| atypical cell | Not usual, abnormal. Cancer is the result of atypical cell division. (09 Oct 1997) |
| bag cell neurons | <cell biology> Cluster of electrically coupled neurons in the abdominal ganglion of Aplysia that are homogeneous, easily dissected out and release peptides that stimulate egg laying. (18 Nov 1997) |
| balloon cell | An unusually large degenerated cell with pale-staining vacuolated or reticulated cytoplasm, as in viral hepatitis or in degenerated epidermal cell's in herpes zoster, a large form of nevus cell with abundant nonstaining cytoplasm, formed by vacular degeneration of melanosomes. (05 Mar 2000) |
| balloon cell nevus | A nevus in which many of the cells are large, with clear cytoplasm. (05 Mar 2000) |
| b and t cell count | A test that measures the respective quantities of B lymphocytes and T lymphocytes. This test is often performed in the analysis of an immune deficiency disorder. Normal values include: 68 to 75% of total lymphocytes are T lymphocytes and 10 to 20% are B lymphocytes. Increased T-cell counts can indicate infectious mononucleosis, acute lymphocytic leukaemia or multiple myeloma. Increased B lymphocytes can indicate chronic lymphocytic leukaemia, multiple myeloma, Waldenstrom's macroglobulinaemia or Di George syndrome. Decreased T-cells may indicate congenital T-cell deficiency, Wiskott-Aldrich syndrome or AIDS. Decreased B-cells may indicate acute lymphocytic leukaemia or a congenital immunoglobulin deficiency disorder. (27 Sep 1997) |
| basal cell | <pathology> General term for relatively undifferentiated cells in an epithelial sheet that give rise to more specialised cells act as stem cells). In the stratified squamous epithelium of mammalian skin the basal cells of the epidermis (stratum basale) give rise by an unequal division to another basal cell and to cells that progress through the spinous, granular and horny layers, becoming progressively more keratinised, the outermost being shed as squames. In olfactory mucosa the basal cells give rise to olfactory and sustentacular cells. In the epithelium of epididymis their function is unclear, but they probably serve as stem cells. (13 Nov 1997) |
| basal cell adenoma | <tumour> A benign tumour of major or minor salivary glands or other organs composed of small cells showing peripheral palisading. (05 Mar 2000) |
| basal cell carcinoma | <oncology, tumour> The most common form of skin cancer. A malignant growth of epidermal tissue, specifically basal cells. most common in the fair-skinned on sun-exposed areas (especially the face). (15 Nov 1997) |
| basal cell epithelioma | <oncology, tumour> The most common form of skin cancer. A malignant growth of epidermal tissue, specifically basal cells. most common in the fair-skinned on sun-exposed areas (especially the face). (15 Nov 1997) |