The Colon

Pertinent to absorption enhancement of drugs it is noteworthy that because of the long residence time of the colon contents, it can be considered as a closed biological compartment  

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Phenolphthaleia is a cathartic dmg and the basis of many OTC laxatives. Its action is mainly on the colon to produce a soft semifluid stool within six to eight hours. Its action may persist for several days owiag to enterohepatic circulation and it may cause red urine if urine is alkaline. 

Lactulose. 4-O-P -D-Galactopyranosyl-4-D-fmctofuranose [4618-18-2] (Chronolac) (12) may be made from lactose using the method described in Reference 9. It is a synthetic disaccharide that is not hydroly2ed by gastrointestinal enzymes in the small intestine, but is metabolized by colonic bacteria to short-chain organic acids. The increased osmotic pressure of these nonabsorbable organic acids results in an accumulation of fluid in the colon. Lactulose may not be tolerated by patients because of an extremely sweet taste. It frequently produces flatulence and intestinal cramps. 

The largest use of endoscopic techniques is in the examination of the gastrointestinal tract. Upper intestinal endoscopy is the examination of the esophagus, stomach, and proximal duodenum. Colonoscopy is the examination of the colon, large intestine, and in some cases the distal parts of the small intestine. Cholangiopancreatography is the examination of the biUary tree and pancreas. 

Gastrointestinal x-ray imaging is the imaging of the small and large intestines and the colon. The contrast between the various tissues found in the abdomen is poor. As a consequence, a contrast agent is introduced into the digestive tract which absorbs more x-rays than do the tissues in the abdomen. 

Whipworm (Trichuris trichiurd) adult females are 5 cm long. These worms thread their entire body into the epithelium of the colon, where they feed on tissue juice and small amounts of blood. Infections of several hundred worms may cause irritation and inflammation of the mucosa, with abdominal pain, diarrhea, and gas. Eggs are discharged and passed into the feces. Infections result from the swallowing of eggs that are obtained directly from contaminated soil. Untreated adult worms Hve for years. 

Balantidiasis (balantidiosis, balantidial dysentery), an intestinal disease seen almost worldwide, is caused by the large ciUated protozoan, balantidium coll The organism is usually found in the lumen of the large intestine of humans and animals. Cysts formed in the lumen of the colon or in freshly evacuated feces of humans or domesticated and wild animals, can colonize the colon and terminal ileum of new hosts by the latter s ingestion of contaminated food or water. The hog has been found to be the most heavily parasitized host. Its association with the rat may be a means for maintaining a reservoir infection in the two animals. 

Balantidiasis in humans is manifest by chronic episodes of intermittent diarrhea and constipation, symptoms similar to those of amebiasis. The patient may also have abdominal pain, tenderness over the colon, anorexia, nausea, severe weight loss, and weakness. The disease may be fatal and, before the avakabihty of a treatment, was the cause of death in approximately 30% of infected individuals. 

The numbei following the colon indicates the numbei of sites of unsatuiation. 

Fiber components are the principal energy source for colonic bacteria with a further contribution from digestive tract mucosal polysaccharides. Rate of fermentation varies with the chemical nature of the fiber components. Short-chain fatty acids generated by bacterial action are partiaUy absorbed through the colon waU and provide a supplementary energy source to the host. Therefore, dietary fiber is partiaUy caloric. The short-chain fatty acids also promote reabsorption of sodium and water from the colon and stimulate colonic blood flow and pancreatic secretions. Butyrate has added health benefits. Butyric acid is the preferred energy source for the colonocytes and has been shown to promote normal colonic epitheUal ceU differentiation. Butyric acid may inhibit colonic polyps and tumors. The relationships of intestinal microflora to health and disease have been reviewed (10). 

This tree ie a White Iron Bark" loond io most ol the colon... 

Jack Products, a U.S. Class 1 railroad and North America s leading independent intermodal terminal operator, respectively, have invested 60 million for start-up expenses to revive and modernize the 143-year old first transcontinental railroad of the Americas. Fnlly operational in 2000, the revitalized railroad provides an efficient intermodal link for world commerce and complements the existing transportation provided by the canal, the Colon Free Trade Zone, and the port terminals. 

Acarbose and Miglitol These agents are specific inhibitors of intestinal glucosidases and reduce the conversion of sucrose and starch to glucose. Their main effect is a delay, not a complete inhibition, of the absorption of carbohydrates. Postprandial blood sugar excursions are effectively reduced. Because a small portion of the carbohydrates enters the colon, their microbial degradation frequently causes flatulence or... 

Colon inflammation 1. AEA levels are elevated in the colon of DNBS-treated mice and in the colon submucosa of TNBS-treated rats, two animal models of inflammatory bowel diseases, and in the biopsies of patients with ulcerative colitis, to control inflammation 1. Inhibitors of degradation (both FAAH and cellular re-uptake)... 

Despite recent developments, effectiveness of chemotherapy is still rather limited for most types of cancer, including tumors of the colon, lung, kidney, pancreas, and liver. Why some cancers respond better than others may be explained by factors relating to the anatomy and physiology of the cancer-ridden organ or... 

Although vitamin K is a fat soluble vitamin, only little stores are found in the body which have to be refilled permanently via dietary input. The role of vitamin K derived from bacteria in the colon is controversely discussed, as the concentration of biliary acids for the resorption the fatsoluble vitamin K is very low in the colon. In addition, only diseases of the small intestine lead to a deficit in vitamin K concentration which cannot be restored by K2 production of colonic bacteria. However, watersoluble vitamin Ks can be resorbed by the colonic mucosa. Maybe because of the little stores for vitamin K, the process of vitamin K-dependent carboxylation of proteins is part of a cycle with several steps during which vitamin K normally is regenerated (see Fig. 1) and thus can be used several times. 

A laxative is most often prescribed for the short-term relief or prevention of constipation. Certain stimulant, emollient, and saline laxatives are used to evacuate the colon for rectal and bowel examinations. Fecal softeners or mineral oil are used prophylactically in patients who should not strain during defecation, such as after anorectal surgery or a myocardial infarction. Psyllium may be used in patients with irritable bowel syndrome and diverticular disease. Fblycarbophil may be prescribed for constipation or diarrhea associated with irritable bowel syndrome and diverticulosis. Mineral oil is... 

Escherichia coli a nonpathogenic colon bacillus when found outside of the colon may cause infection e st ro ge ns female ho rmo lies e uthy roid no rmal thyroid functio n... 

The permeability of the films to paracetamol as a model compound was dependent on film composition and was markedly increased after exposure to pectinolytic enzymes, used to mimic conditions in the colon. Similar formulations, apphed as a film coat to tablets, were used with colonic conditions for an increased release rate [242],... 

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