Lower gastrointestinal tract

It has recently been shown (14) that nitrate from food can be detected in the feces of germfree animals but not in the feces of conventional animals. This result and the results of Witter et al. (18-20) suggest that nitrate is available in the lower gastrointestinal tract and is metabolized by the microbial flora. The intestine may thus be a site for the endogenous formation of N-nitroso compounds. 

It is conceivable that nltrosamlnes can be synthesized In the Intestine, since the precursors are present. While the conditions for aqueous nltrosatlon reactions are not optimum at pH values encountered In the lower gastrointestinal tract, several studies have shown that these reactions can be catalyzed (39, 40, 41). It has been suggested that the Intestine might be a site for the formation of nltrosamlnes by bacterial action (42). Sander (43) has demonstrated the formation of nltrosamlnes by bacterial action from precursor amines and nitrate at neutral pH and Klubes and coworkers have reported the formation of NDMA. upon Incubation of l C-dlmethylamlne and sodium nitrite with rat fecal contents (44, 45). 

Barium enema A diagnostic test using x-ray examination to view the lower gastrointestinal tract (colon and rectum) after oral ingestion of barium sulfate, a chalky liquid contrast medium. 

The gastrointestinal tract is conveniently divided into a number of areas, primarily on the basis of morphology and function. For most pharmaceutical purposes, we can group the target tissues into three regions the upper, mid- and lower gastrointestinal tract. 

The oral cavity and the lower gastrointestinal tract are densely colonized by bacteria with counts exceeding 109 colony-forming units (CFU)/ml, whereas the density in the stomach and proximal small bowel is normally below 105 CFU/ml (fig. 1). Bacterial density increases through... 

The absence of Gram-negative bacilli is a reliable and valid indication of preserved intestinal clearance, which precludes a significant failure of intestinal motility and anatomical abnormalities inducing stasis or recycling of contents from the lower gastrointestinal tract. 

Lower gastrointestinal tract motility regulators trimebutine maleate... 

Dosages and routes of administration Morphine is available in different salt forms but the hydrochloride and sulfate (Vermeire and Remon, 1999) are used preferentially. The compound can be administered by the oral, parenteral or intraspinal route. Oral application is preferred for chronic pain treatment and various slow release forms have been developed to reduce the administration frequency to 2-3 times per day (Bourke et al., 2000). Parenteral morphine is used in intravenous or intramuscular doses of 10 mg, mostly for postoperative pain and self-administration devices are available for patient-controlled analgesia (PCA). Morphine is additionally used for intraspinal (epidural or intrathecal) administration. Morphine is absorbed reasonably well in the lower gastrointestinal tract and can be given as suppositories. 

Methadone is a synthetic opioid, clinically available in the U.S. since 1947.8 It exists in the dextro- and levo-rotatory forms with the levo-isoform possessing approximately 8 to 50 times more pharmacological activity.27 34 Methadone acts on the CNS and cardiovascular system producing respiratory and circulatory depression. Methadone also produces miosis and increases the tone of smooth muscle in the lower gastrointestinal tract while decreasing the amplitude of contractions. It is used clinically for the treatment of severe pain and in maintenance programs for morphine and heroin addicts.34... 

Celiac Disease. A disturbance of the lower gastrointestinal tract, celiac disease is a chronic disease characterized by loss of appetite and weight, depression and irritability, and diarrhea frequendy followed by constipation (35). One of the more disturbing features of celiac disease is the large, frothy, foul-smelling stools. The disease may develop in childhood or later in life. Frequendy, the patients who develop the disease in adulthood report having had some of the symptoms during childhood. 

Balantidiasis Lower gastrointestinal tract Iodoquinol [tetracycline antibiotics are also effective] Metronidazole... 

Berner, B., and Louie-Helm, J. Gastric retentive oral dosage forms with restricted drug release in the lower gastrointestinal tract, U.S. Patent 2003014052, 2003. 

Rofecoxib, a furanose derivative, is a potent, selective COX-2 inhibitor (Table 36-1). In the USA, rofecoxib is approved for osteoarthritis and rheumatoid arthritis, and it also appears to be analgesic and antipyretic—in common with other NSAIDs. This drug does not inhibit platelet aggregation and appears to have little effect on gastric mucosal prostaglandins or lower gastrointestinal tract permeability. At high doses it is associated with occasional edema and hypertension. Other toxicities are similar to those of other coxibs. 

Aluminum is also found in human skin (Alfrey 1980 Tipton and Cook 1963), lower gastrointestinal tract (Tipton and Cook 1963), lymph nodes (Hamilton et al. 1972/73), adrenals (Stitch 1957 Tipton and Cook 1963), and parathyroid glands (Cann et al. 1979). There is evidence that with increasing age of humans, aluminum concentrations may increase in the lungs and brain tissue (Allfey 1980 Crapper and DeBoni 1978 Markesbery et al. 1981 McDermott et al. 1979 Stitch 1957 Tipton and Shafer 1964). 

W.L. Janower, Hypersensitivity reactions after barium studies of the upper and lower gastrointestinal tract. Radiology 161 139-140, 1986. 

Ulcerative colitis is an inflammatory disease of the lower gastrointestinal tract, which results in episodes of diarrhoea. There may also be extraintestinal symptoms, including anaemia, arthritis, dermatological problems and eye disorders. 

Although systemic absorption of the prednisolone from the enema probably does occur, especially when the colon is particularly inflamed, corticosteroids usually have less systemic effects when given this way. Furthermore, by giving an enema, the drug is being delivered directly to its site of action - remember that in ulcerative colitis the disease is confined to the lower gastrointestinal tract. 

Altering the rate of gastric emptying and lower gastrointestinal tract transit influences the absorption of any co-administered drugs. 

Treatment of haemorrhagic complications in acute or chronic liver disease initially focuses on the site of bleeding, i.e. in the upper or lower gastrointestinal tract. Mechanical, thermal and sclerotic measures are of prime importance. 

Adams PL, Rutsky EA, Rostand SG, Han SY. Lower gastrointestinal tract dysfnnction in patients receiving longterm hemodialysis. Arch Intern Med 1982 142(2) 303-6. 

Smith HJ, Jones K, Hunter TB. What happens to patients after upper and lower gastrointestinal tract barium studies Invest Radiol 1988 23(ll) 822-6. 

Colitis was observed during endoscopy of the lower gastrointestinal tract in 21 patients (14). Some patients developed rectal bleeding, tenesmus, and increased frequency of stools, lasting 12 days. 

Vang R, Gown AM, Zhao C, et al. Ovarian mucinous tumors associated with mature cystic teratomas Morphologic and immunohistochemical analysis identifies a subset of potential teratomatous origin that shares features of lower gastrointestinal tract mucinous tumors more commonly encountered as secondary tumors in the ovary. Am J Surg Pathol. 2007 31 854-869. 

Adverse effects of methotrexate include ulceration of the mouth and lower gastrointestinal tract and bone marrow suppression. With high doses of methotrexate synthetic folinates are used to prevent irreversible bone marrow damage. 

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