Biotransformation enzymes in human intestine: critical low levels in the colon?

Article Abstract:

Biotransformation enzymes are those that catalyze a change in the physical form of ingested non-nutritive substances, usually converting them to an inactive or nontoxic state. A large proportion of the body's biotransformation occurs in the liver, but a significant amount occurs in the small and large intestines during the digestion and absorption of food. Little is known about the localization or molecular nature of the biotransformation enzymes in the gastrointestinal tract. To investigate the distribution and composition of biotransformation enzymes in the small and large intestine, intestinal segments were removed post mortem from formerly healthy kidney donors, and analyzed for the presence and type of three different enzymes: glutathione S-transferase, uridine diphosphate-glucuronosyltransferase, and cytochrome P-450. The activity of each of the three enzymes decreased slightly from the beginning to the end segments of the small intestine; there was a large decrement in activity at the transition from the small to the large intestine. Additionally, the molecular configuration of each of the enzymes was slightly different at different levels of the intestine; once again, the largest differences were seen between the large and small intestines. The low levels of biotransformation enzymes seen in the large intestine of these healthy subjects might be a partial explanation for the higher rates of cancer seen in the large (compared to small) intestine; toxins which escape degradation in the small intestine are less likely to be degraded upon arrival at the large intestine, and are more likely to exert toxic effects. (Consumer Summary produced by Reliance Medical Information, Inc.)

Gastrointestinal system, Digestive enzymes

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Colorectal cancer in ulcerative colitis: influence of anatomical extent and age at onset on colitis-cancer interval

Article Abstract:

Ulcerative colitis is an inflammatory bowel disease affecting the colon, characterized by the passage of watery stools, abdominal pain, tenderness, and colic. In severe cases, perforation and hemorrhage may occur, which can be fatal. The progression of ulcerative colitis to colorectal cancer is rare, but ulcerative colitis patients are at greater risk of developing colorectal cancer than is the population at large. To investigate the factors that may be important in determining the time course with which ulcerative colitis may progress to a cancerous condition, data from a group of 100 patients treated for both ulcerative colitis and colitis-related colorectal cancer between 1959 and 1988 were analyzed. There was a strong relationship between the age of onset of the colitis and the age at which cancer was diagnosed. Patients who were older at the time of colitis onset tended to be older when cancer was diagnosed; similarly, younger colitis patients were diagnosed with cancer at a younger age. The average time that elapsed between the colitis and cancer diagnosis was about 20 years, with range between 5 and 46 years among the patients. This relationship was seen in colitis patients with a variety of different subtypes of the disease. Patients with left-sided colitis developed both the colitis and the subsequent colorectal cancer about 10 years later than did patients with extensive colitis. However, the duration of colitis prior to onset of cancer was identical in the two groups. (Consumer Summary produced by Reliance Medical Information, Inc.)

Complications and side effects, Risk factors, Colorectal cancer, Prognosis, Ulcerative colitis, Colitis

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Primary atypical mycobacteriosis of the intestine: a report of three cases

Article Abstract:

Primary atypical mycobacteriosis, a tuberculous-like bacterial disease, fairly commonly affects the lung but primary atypical mycobacteriosis of the intestine has received little attention up until now. Three patients with primary atypical mycobacteriosis of the intestine were treated with antituberculous drugs. Treatment was effective in all three cases. Doctors must be aware that atypical mycobacterium may be present in patients with Crohn's disease, in patients with ulcerative colitis and even in healthy patients. Therefore, the diagnosis of atypical mycobacteriosis can be complicated and clinicians should look for repeated discharge of atypical mycobacteria in large numbers, the presence of clinical symptoms that may be attributed to these bacilli, the presence of a lesion containing atypical mycobacterial and the histopathologic changes possibly as a result of the bacilli. It is suggested that these findings may belong to a newly defined, independent disease.

Evaluation, Gastrointestinal diseases, Mycobacterial infections, Mycobacterium infections, Antitubercular agents

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