[Gastrointestinal hemorrhage of obscure origin].

Gastrointestinal bleeding of obscure origin consists of recurrent bouts of acute or chronic bleeding for which no definite source is discovered in routine endoscopic and barium contrast studies of the upper and lower gastrointestinal tracts. Usually its cause is angiodysplasia of the intestine, but many cases are due to tumors, mostly of the small bowel, which may be malignant. In patients under the age of 50, the proportion with malignancy is relatively high (up to 14%) as compared to older patients.

[Screening for colorectal neoplasms].

We screened groups at high risk for colorectal neoplasms, determining the efficacy of the leukocyte adherence inhibition test (LAI) for early detection, in comparison with that of the fecal occult blood (Hemoccult) test and sigmoidoscopy or colonoscopy. Those screened included 549 first-degree relatives of patients with colorectal cancer, 190 patients with a past history of colorectal adenoma or carcinoma and 67 with a past history of breast or gynecological cancer or inflammatory bowel disease. 146 normal volunteers served as controls.

Antitumor immune response to colorectal cancer antigen detected by the leukocyte adherence inhibition test (LAI) in groups at high risk for colorectal cancer.

Colorectal cancer is the second leading cause of cancer death in western populations. As treatment outcome is highly correlated with stage at diagnosis, early detection is a very important task. Three high-risk groups for colorectal cancer (first-degree relatives of colorectal cancer patients; individuals with past history of colorectal neoplasms, polyps, or carcinoma; and patients with ulcerative colitis) were screened for colonic neoplasms.