| bay region | <chemistry> An indentation of three fused benzene rings. A common bay region is the site on benzo(a)pyrene, an indirect carcinogen that is metabolically activated by the p-450 system at the 7,8-double bond, leading to a 7,8-oxide, which is rapidly converted to a 7,8-dihydrodiol and later epoxidated near the bay region at the 9,10-double bond. The resulting product, a diol-epoxide is a poor substrate for epoxide hydratase and is released from the mitochondria into the cell as a highly reactive electrophil, becoming an ultimate carcinogen, as it reacts with negative charges in DNA. (25 Jun 1999) |
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| branchial region | Region containing paired arched columns that bear gills in lower aquatic vertebrates and appear in the embryos of higher vertebrates in comparable form. In higher vertebrates the arches are subsequently modified into structures of the neck and ear. (12 Dec 1998) |
| breakpoint cluster region | A region on chromosome 22 that is involved in the Philadelphia translocation. Acronym: BCR (15 Nov 1997) |
| buccal region | The region of the cheek, corresponding approximately to the outlines of the underlying buccinator muscle. Synonym: regio buccalis. (05 Mar 2000) |
| calcaneal region | The region of the heel. Synonym: regio calcanea. (05 Mar 2000) |
| caribbean region | The area that lies between continental north and south america and comprises the caribbean sea, the west indies, and the adjacent mainland regions of southern mexico, central america, colombia, and venezuela. (12 Dec 1998) |
| variable region | <molecular biology> Those regions in the amino acid sequence of both the heavy and the light chains of immunoglobulins where there is considerable sequence variability from one immunoglobulin to other of the same class, in contrast to constant sequence (C) regions. The V regions are associated with the antigen binding areas. They contain hypervariable regions of particularly high sequence diversity. (18 Nov 1997) |
| mammary region | The region of the breast. Synonym: regio mammaria. (05 Mar 2000) |
| vertebral region | The central region of the back, corresponding to the underlying vertebral column. Synonym: regio vertebralis. (05 Mar 2000) |
| parietal region | The surface region of the head corresponding to the outlines of the underlying parietal bone. Synonym: regio parietalis capitis. (05 Mar 2000) |
| region | <anatomy> A plane area with more or less definite boundaries. (18 Nov 1997) |
| region of interest | In computed tomography or other computerised imaging, an interactively selected portion of the image, whose individual or average pixel values can be displayed numerically. (05 Mar 2000) |
| region of olfactory mucosa | The specialised olfactory receptive area that includes the upper one-third of the nasal septum and the lateral wall above the superior concha; it is lined with olfactory mucosa. Synonym: regio olfactoria tunicae mucosae nasi, olfactory region of tunica mucosa of nose, Schultze's membrane. (05 Mar 2000) |
| region, regulatory | See: Regulatory sequence. (12 Dec 1998) |
| regulatory region | <molecular biology> A DNA base sequence that controls gene expression. (14 Oct 1997) |