Gastro-intestinal tract

TAMMINGA s, SCHULZE H, VAN BRUCHEM J, HUISMAN J (1995) The nutritional significance of endogenous N-losses along the gastro-intestinal tract of farm animals. Arch Tieremahr. 48 9-22. 

Penicillamine is well absorbed (40-70%) from the gastro-intestinal tract and, therefore, has a decided advantage over many chelating agents. Food, antacids, and iron reduce its absorption, so it should be taken on an empty stomach. Preferably, the... 

Pigments are passed via the gastro-intestinal tract and not discharged via the urethra. According to the results of these studies, organic pigments show practically no acute toxicity. 

In Sect. Ill evidence has been presented which indicates that only small quantities of actinides pass from soil into plants. The uptake of the actinides from the gastro-intestinal tract is slow (Tables 7a and b). 

From an examination of Tables 7a and b it is apparent that in very young animals there is an increased uptake of actinides across the gastro-intestinal tract. It is known than in suckling animals there is a more rapid accumulation of iron than there is in adult animals. Presumably actinide uptake is a result of entrainment in the iron transporting processes. 

Table 7 a. Actinide uptake from gastro-intestinal tract... 

Kobayashi M, Sada N, Sugawara M, Iseki K, Miyazaki K (2001) Development of a new system for prediction of drug absorption that takes into account drug dissolution and pH change in the gastro-intestinal tract. Int J Pharm 221 87-94. 

Numerous studies have been published on the in vivo metabolism of peptides. However, these studies are concerned mainly with assessment of pharmacokinetic parameters such as half-life and clearance. Only seldom is the in vivo biotransformation of peptides that contain only common amino acids investigated in any detail, due to the difficulty of monitoring products of proteolysis that are identical to endogenous peptides and amino acids. More importantly, such studies fail to yield mechanistic and biochemical insights. For this reason, we begin here with a discussion of the metabolism of just a few peptides in some selected tissues, namely portals of entry (mouth, gastro-intestinal tract, nose, and skin), plasma, organs of elimination (liver, kidney), and pharmacodynamic sites (brain and cerebrospinal fluid). These examples serve as introduction for the presentation in Sect. 6.4.2 of the involvement of individual peptidases in peptide metabolism. 

Together these data suggest that bile acids may induce mutations in DNA, and reinforces the notion that bile acids may play a key role as carcinogens or co-carcinogens in the gastro-intestinal tract. 

There are three main sources of evidence for pro-tumorigenic activity of bile acids in the lower gastro-intestinal tract (activity in rodent CRC models, human observational data and mechanistic studies using CRC cells in vitro), which together create a strong case for a role for colorectal mucosal bile acid exposure during human colorectal carcinogenesis. 

Treatment of constipation and other disorders of the gastro-intestinal tract may reduce flatulence problems. Medicines that increase peristalsis should not be used because of the risk of adverse reactions. 

The nonsteroidal antiinflammatory drugs like aspirin, indomethacin and phenylbutazone causes ulceration in gastro-intestinal tract which provides a site for bleeding in patients on anticoagulants. 

Enterosgel for Treatment of Diseases of the Gastro-intestinal Tract... 

Of significant interest is an attempt to nse Enterosgel for therapy of chronic hard-to-treat diseases of gastro-intestinal tract snch as malabsorption syndrome, gluten enteropathy, exacerbation of chronic enteritis, post-resection syndrome and the syndrome of irritated large bowel. 

Prophylactic and therapeutic administration of Enterosgel to rats with experimental peptic ulcer and ulcerative colitis, significantly decreased the number and surface area of lesions on gastro-intestinal tract (GIT) mucosa and reduced the severity of the syndrome of endogenous intoxication that accompanied these injuries [21, 22]. The first evidence of clinical use of Enterosgel in combined therapy of peptic gastric ulcer and duodenum was reported by S.M. Tkach, who had noted that enterosorp-tion significantly reduced the number of side effects of treatment, and the rate of Helicobacter eradication increased from 83.3 to 93.3% [23]. 

In Vivo Dissolution The process of dissolution of drug in the gastro-intestinal tract. 

The intestinal inhibitory action of opioids can be used for treatment of diarrhea (De Luca and Coupar, 1996). The clinically most important anti-diarrheal opioid is loperamide (Heel et al., 1978). After oral administration, loperamide acts locally within the gastro-intestinal tract. After parenteral administration, the compound is rapidly inactivated and does not reach the CNS. Therefore loperamide does not show the typical central opioid side-effects, has no analgesic action and has no abuse potential. 

Hunjan, M.K. and D.F. Evered. 1985. Absorption of glutathione from the gastro-intestinal tract. Biochim Biophys Acta 815 184. 

Guarini, S., and W. Ferrari. 1985. Olive oil-provoked bile-dependent absorption of heparin from gastro-intestinal tract in rats. Pharmacol Res Commun 17 685. 

Enzyme assays As shown previously the LMW fraction had a repressing effect on the protein digestion in the in vivo experi-ment. Accordingly, it was of interest to study in vitro the effect of this fraction on the kinetics of reactions catalyzed by proteases and peptidases present in the gastro-intestinal tract. 

Most studies show that bioaccumulation predominantly results from chemical absorption directly from water via the respiratory surface (e.g., gills and/or skin) of the organism (i.e., bioconcentration) and from diet via the gastro-intestinal tract (i.e., biomagnification). Exceptions occur e.g., phytoplankton species generally do not absorb chemical by dietary ingestion, organisms obtain chemical via maternal transfer, and some species contain unique mechanisms for chemical uptake and elimination. 

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