| mast cell | <cell biology, immunology> Resident cell of connective tissue that contains many granules rich in histamine and heparan sulphate. Release of histamine from mast cells is responsible for the immediate reddening of the skin in a weal and flare response. Very similar to basophils and possibly derived from the same stem cells. Two types of mast cells are now recognised, those from connective tissue and a distinct set of mucosal mast cells, the activities of the latter are T-cell dependent. (05 Jan 1998) |
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| mast cell leukaemia | A form of granulocytic leukaemia in which there are unusually great numbers of basophilic granulocytes in the tissues and circulating blood; in some instances, the immature and mature basophilic forms may represent from 40 to 80% of the total numbers of white blood cells. Synonym: mast cell leukaemia. (05 Mar 2000) |
| ghost cell | <haematology> A red blood cell which has had all of its cytoplasmic contents removed by cell lysis so that only its outer cytoplasmic membrane remains. (17 Dec 1997) |
| ghost cell glaucoma | Glaucoma occurring after vitrectomy, arising from erythrocyte membranes blocking outflow channels of aqueous humor. (05 Mar 2000) |
| giant cell | <pathology> A cell of large size, often with many nuclei. They are multinucleated masses produced by the fusion of many cells. They are often associated with viral infections. In AIDS, they are induced when the envelope glycoprotein of HIV binds to the CD4 antigen of uninfected neighboring T4 cells. The resulting syncytium leads to cell death and thus may account for the cytopathic effect of the virus. (18 Jul 2002) |
| giant cell aortitis | <pathology> Giant cell arteritis involving the aorta. (05 Mar 2000) |
| giant cell arteritis | <pathology> An inflammatory condition of the temporal artery. It is a serious chronic vascular disease, characterised by inflammation of the walls of the blood vessels (vasculitis). The age of affected patients is usually over 50 years of age. It most often involves the carotid artery system, and can lead to blindness or stroke. It can be diagnosed by biopsy of an artery, but there is often a false negative result. Elevation of the erythrocyte sedimentation rate is typical. Treatment is with high dose steroids. Common symptoms include headaches and tenderness over the temple (temporal artery). Can be associated with polymyalgia rheumatica. See: polymyalgia rheumatica. Synonym: cranial arteritis, temporal arteritis (20 Jun 2000) |
| giant cell astrocytoma | <radiology> Malignant transformation from hamartoma (tuber) of tuberous sclerosis, enhances (unlike benign lesions), arises only about foramen of Monro, not really an astrocytoma, it's a giant-cell tumour (12 Dec 1998) |
| giant cell carcinoma | <tumour> A malignant epithelial neoplasm characterised by unusually large anaplastic cells. (05 Mar 2000) |
| giant cell carcinoma of thyroid gland | A rapidly progressive undifferentiated carcinoma observed in the thyroid gland, characterised by numerous, unusually large, anaplastic cells derived from glandular epithelium of the thyroid gland. (05 Mar 2000) |
| giant cell epulis | <dermatology, oncology> A non-neoplastic lesion characterised by a proliferation of granulation tissue containing numerous multinucleated giant cells. It occurs on the gingiva and alveolar mucosa (occasionally on other soft tissues) where it presents as a soft red-blue haemorrhagic nodular swelling. It also occurs within the mandible or maxilla as a unilocular or multilocular radiolucency. Peripheral giant cell granuloma refers to the gingiva (giant cell epulis), central refers to the jaw. Microscopically similar lesions occur in the tubular bones of the hands and feet, are considered neoplastic, and may have a malignant course. Identical bony lesions may be seen in hyperparathyroidism and cherubism. See: giant cell tumour of bone. Synonym: giant cell epulis. (05 Mar 2000) |
| giant cell fibroma | <tumour> A tumour of the oral mucosa composed of fibrous connective tissue with large stellate and multinucleate fibroblasts; shares a similar histology with the retrocuspid papilla, fibrous papule of the nose, pearly penile papule, and the ungual fibroma. (05 Mar 2000) |
| giant cell granuloma | <dermatology, oncology> A non-neoplastic lesion characterised by a proliferation of granulation tissue containing numerous multinucleated giant cells. It occurs on the gingiva and alveolar mucosa (occasionally on other soft tissues) where it presents as a soft red-blue haemorrhagic nodular swelling. It also occurs within the mandible or maxilla as a unilocular or multilocular radiolucency. Peripheral giant cell granuloma refers to the gingiva (giant cell epulis), central refers to the jaw. Microscopically similar lesions occur in the tubular bones of the hands and feet, are considered neoplastic, and may have a malignant course. Identical bony lesions may be seen in hyperparathyroidism and cherubism. See: giant cell tumour of bone. Synonym: giant cell epulis. (05 Mar 2000) |
| giant cell hepatitis | Hepatitis in the neonatal period presumed to be due to a variety of causes, chiefly viral; characterised by direct and indirect bilirubinaemia, hepatocellular degeneration, and appearance of multinucleated giant cells; may be difficult to distinguish from biliary atresia, but is more likely to end with recovery, although cirrhosis may develop. Synonym: giant cell hepatitis. (05 Mar 2000) |
| giant cell hyaline angiopathy | <pathology> An inflammatory infiltrate containing foreign body giant cells and eosinophilic material. Fragments of foreign material resembling vegetable matter may be included. Synonym: pulse granuloma. (05 Mar 2000) |