| giant cells, langhans | Multinucleated cells (fused macrophages) seen in granulomatous inflammations such as tuberculosis, syphilis, sarcoidosis, and deep fungal infections. They resemble foreign-body giant cells (giant cells, foreign body) but langhans giant cells contain less chromatin and their nuclei are arranged peripherally in a horseshoe-shaped pattern. Langhans giant cells occur frequently in delayed hypersensitivity. (12 Dec 1998) |
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| giant chromosome | <cell biology> Giant chromosomes produced by the successive replication of homologous pairs of chromosomes, joined together (synapsed) without chromosome separation or nuclear division. They thus consist of many up to 1000) identical chromosomes (strictly chromatids) running parallel and in strict register. The chromosomes remain visible during interphase and are found in some ciliates, ovule cells in angiosperms and in larval Dipteran tissue. The best known polytene chromosomes are those of the salivary gland of the larvae of Drosophila melanogaster which appear as a series of dense bands interspersed by light interbands, in a pattern characteristic for each chromosome. The bands, of which there are about 5,000 in Drosophila melanogaster, contain most of the DNA (ca 95%) of the chromosomes and each band roughly represents one gene. The banding pattern of polytene chromosomes provides a visible map to compare with the linkage map determined by genetic studies. Some segments of polytene chromosome show chromosome puffs, areas of high transcription. (18 Nov 1997) |
| giant colon | An abnormally large or dilated colon, the condition may be congenital or acquired, acute or chronic. (18 Nov 1997) |
| giant condyloma | A large type of condyloma acuminatum found in the anus, vulva, or preputial sac of the penis of middle-aged, uncircumcised men; it tends to extend deeply and recur. Synonym: Buschke-Lowenstein tumour. (05 Mar 2000) |
| giant drusen | An obsolete term for a glial hamartoma of the optic nerve head or the peripapillary retina, seen in tuberous sclerosis. (05 Mar 2000) |
| giant follicular lymphoblastoma | <tumour> A malignant lymphoma arising from lymphoid follicular B-cells which may be small or large, growing in a nodular pattern. Synonym: follicular lymphoma, giant follicular lymphoblastoma. (05 Mar 2000) |
| giant follicular thyroiditis | A variant of Hashimoto's thyroiditis in which lymphocytic infiltrate in thyroid has formed into giant follicles. (05 Mar 2000) |
| giant gastric folds | Enlarged gastric submucosal ridges covered by hyperplastic mucosa, as seen in Zollinger-Ellison syndrome, Menetrier's disease, and hypertrophic hypersecretory gastropathy. (05 Mar 2000) |
| giant hairy nevus | <dermatology> These large pigmented (often hairy) congenital nevi are important because of their increased risk (10 to 15%) of conversion into malignant melanoma. A biopsy can confirm if cells have turned malignant. Any change in a pre-existing nevus should prompt a physician evaluation. (17 Dec 1997) |
| giant hives | A vascular reaction involving the deep dermis or subcutaneous or submucal tissues, representing localised oedema caused by dilatation and increased permeability of the capillaries and characterised by development of giant wheals. (18 Nov 1997) |
| giant hypertrophy of gastric mucosa | Gastric mucosal hyperplasia, either mucoid or glandular; the latter type may be associated with the Zollinger-Ellison syndrome. Synonym: giant hypertrophy of gastric mucosa, hypertrophic gastritis, Menetrier's syndrome. (05 Mar 2000) |
| giant lymph node hyperplasia | Large benign, hyperplastic lymph nodes. The more common hyaline vascular subtype is characterised by small hyaline vascular follicles and interfollicular capillary proliferations. Plasma cells are often present and represent another subtype with the plasma cells containing IgM and IgA. (12 Dec 1998) |
| giant melanosome | A large spherical melanosome (1 to 6 u in diameter) formed in the cytoplasm of melanocytes in cafe-au-lait spots and other melanocytic disorders. Synonym: macromelanosome. (05 Mar 2000) |
| giant osteoid osteoma | A benign, painful, tumour of bone characterised by the formation of osteoid tissue, primitive bone and calcified tissue. It occurs frequently in the spine of young persons. (12 Dec 1998) |
| giant pigmented nevus | These large pigmented (often hairy) congenital nevi are important because of their increased risk (10 to 15%) of conversion into malignant melanoma. A biopsy can confirm if cells have turned malignant. Any change in a pre-existing nevus should prompt a physician evaluation. (27 Sep 1997) |