| on-off phenomenon | A state in the treatment of Parkinson's disease by l-dopa, in which there is a rapid fluctuation of akinetic (off) and choreoathetotic (on) movements. (05 Mar 2000) |
|---|---|
| ordered on-random off mechanism | A scheme for substrate binding and product release for multisubstrate enzymes; for a two-substrate two-product enzyme with this mechanism, the individuals have to bind to the enzyme in a distinct order; however, once the products are formed they may dissociate from the enzyme in either order. It has been suggested that pyruvate kinase has such a mechanism. The random on-ordered off mechanism is simply the reverse of this mechanism. (05 Mar 2000) |
| adenomatous colon polyps | <radiology> Probability of malignancy by size and type Size (cm) less than 1 1-2 greater than 2 --------------------------- tubular 1% 10% 34% mixed (TV) 4% 9% 45% villous 10% 10% 54%, most colon polyps (90%) are hyperplastic (size less than 5 mm) (12 Dec 1998) |
| arterial arches of colon | Anastomosing branches of the colic arteries that form arch's in the mesocolon from which the walls of the colon are supplied. See: marginal artery of colon. (05 Mar 2000) |
| ascending colon | <anatomy> The first part of the colon (large intestine) that starts in the right lower quadrant of the abdomen and ends at the transverse colon in the right upper quadrant of the abdomen. (27 Sep 1997) |
| bands of colon | teniae coli |
| cancer, colon | A malignant tumour arising from the inner wall of the large intestine. The third leading cause of cancer in males, fourth in females in the U.S. Risk factors for cancer of the colon and rectum (colorectal cancer) include heredity, colon polyps, and long standing ulcerative colitis. most colorectal cancers develop from polyps. Removal of colon polyps can prevent colorectal cancer. Colon polyps and early cancer can have no symptoms. Therefore, regular screening is important. Diagnosis can be made by barium enema or by colonoscopy with biopsy confirmation of cancer tissue. Surgery is the most common treatment for colorectal cancer. (12 Dec 1998) |
| cancer, colon: screening and surveillance | Colon cancer is both preventable and curable. It is preventable by removing precancerous colon polyps. It is curable if early cancer is surgically removed before cancer spread to other parts of the body. Therefore, if screening and surveillance programs were practiced universally, there would be a major reduction in the incidence and mortality of colon cancer. (12 Dec 1998) |
| marginal artery of colon | Artery formed by anastomoses between the right and left colic artery's; it passes downward from the left colic flexure to the aboral end of the pelvic colon. Synonym: artery of Drummond, Riolan's arc. (05 Mar 2000) |
| giant colon | An abnormally large or dilated colon, the condition may be congenital or acquired, acute or chronic. (18 Nov 1997) |
| mesentery of sigmoid colon | See: mesocolon. (05 Mar 2000) |
| mesentery of transverse colon | See: mesocolon. (05 Mar 2000) |
| colon | <anatomy> Also called the large intestine. This structure has 6 major divisions: caecum, ascending colon, transverse colon, descending colon, sigmoid colon and rectum. The total length is approximately 5 feet in the adult and it is responsible for forming, storing and expelling waste matter. (27 Sep 1997) |
| colon ascendens | <anatomy> The first part of the colon (large intestine) that starts in the right lower quadrant of the abdomen and ends at the transverse colon in the right upper quadrant of the abdomen. (27 Sep 1997) |
| colon bacillus | <bacteria> The archetypal bacterium for biochemists, used very extensively in experimental work. A rod shaped gram-negative bacillus (0.5 x 3-5 m) abundant in the large intestine (colon) of mammals. Abbreviation: E. Coli (18 Nov 1997) |