In intestinal tract

Periplanone-A and periplanone-B have been found to occur in a ratio of 1 10 in faecal material of Periplaneta americana, but only periplanone-B has been found in intestinal tracts. This could suggest that periplanone-B is a genuine sex pheromone, whereas periplanone-A could be a biologically active transformation product, which in turn can isomerize into a more stable but inactive compound. We have given hypothetical schemes for such a transformation elsewhere (32,40). 

Serotonin-producing tumors arising in intestinal tract. 

Bile salts Facilitate digestion of saponifiable lipids facilitate absorption of fat-soluble vitamins (A, D, E, K) in intestinal tract... 

Vitamin D Controls calcium absorption in intestinal tract and deposition in bone... 

Escherichia coli normally lives in intestinal tracts and, in particular, in the large intestine of human beings and warm-blooded animals. Outside the intestinal tract, it can only live for a short time in water and in the ground and therefore indicates relatively fresh faecal contamination. Thus, when Escherichia coli is present in water, one also has to reckon on the presence of pathogenic intestinal bacteria such as Salmonella, Shigella and cholera vibrios. Escherichia coli is easy to cultivate on culture mediums and can, by reason of its metabolic characteristics in the so-called... 

Salmonella A bacteria found in intestinal tracts of humans and animals and can cause salmonellosis. It can transmit to humans through meat, fish, and eggs. The bacteria are destroyed by heat and certain chemical germicides. 

Atropiae (41), isolated from the deadly nightshade Airopa belladonna L.) is the racemic form, as isolated, of (—)-hyoscyamine [which is not isolated, of course, from the same plant but is typically found ia solanaceous plants such as henbane (HyosQiamus mgerl. )]. Atropiae is used to dilate the pupil of the eye ia ocular inflammations and is available both as a parasympatholytic agent for relaxation of the intestinal tract and to suppress secretions of the saUvary, gastric, and respiratory tracts. In conjunction with other agents it is used as part of an antidote mixture for organophosphorus poisons (see Chemicals in war). 

Coccidiosis is a proto2oal disease of the intestinal tract of animals that leads to severe loss of productivity and death. The development and widespread use of anticoccidials has revolutionized the poultry industry. The estimated world market for anticoccidial agents in 1989 was 425 million and this was dominated by the polyether ionophore antibiotics monensin, salinomycin [53003-10-4], n imsm [55134-13-9], la.s9locid, and maduramicin [84878-61-5] (26). 

Health and Safety Factors. The strontium ion has a low order of toxicity, and strontium compounds are remarkably free of toxic hazards. Chemically, strontium is similar to calcium, and strontium salts, like calcium salts, are not easily absorbed by the intestinal tract. Strontium carbonate has no commonly recognized hazardous properties. Strontium nitrate is regulated as an oxidizer that promotes rapid burning of combustible materials, and it should not be stored in areas of potential fire hazards. 

Absorption of mannitol (209), sorbitol (210), and xyfltol (4) from the intestinal tract is relatively slow, compared to that of glucose. In humans, approximately 65% of orally adrninistered mannitol is absorbed in the dose range of 40—100 g. About one-third of the absorbed mannitol is excreted in the urine. The remainder is oxidized to carbon dioxide (211). 

A variety of therapies for thallium poisoning have been suggested by neutralising thallium in the intestinal tract, hastening excretion after resorption, or decreasing absorption. Berlin-Blue (fertihexacyanate) and sodium iodide in a 1 wt % solution have been recommended. Forced diuresis hemoperfusion and hemodialysis in combination results in the elimination of up to 40% of the resorbed thaHous sulfate (39). 

A bacteriological examination of water is primarily carried out to determine the possible presence of harmful microorganisms. Testing is actually done to detect relatively harmless bacteria called colon bacilli commonly called the coliform group, which are present in the intestinal tract of humans and animals. If these organisms are present in a water in sufficient number, then this is taken to be evidence that other harmful pathogenic bacteria may also be present. 

Toxicology. The toxicity of ethyl ether is low and its greatest hazards in industry are fire and explosion. The vapor is absorbed almost instandy from the lungs and very prompdy from the intestinal tract. It undergoes no chemical change in the body. Prevention and control of health hazards associated with the handling of ethyl ether depend primarily on prevention of exposure to toxic atmospheric concentrations and scmpulous precautions to prevent explosion and fire. 

Most ACE inhibitors are prodrugs, with the exceptions of captopril, lisinopril, and ceranapril. Prodrugs exert improved oral bioavailability, but need to be converted to active compounds in the liver, kidney, and/or intestinal tract. In effect, converting enzyme inhibitors have quite different kinetic profiles with regard to half time, onset and duration of action, or tissue penetration. 

When a-glucosidase activity is inhibited, carbohydrate digestion is prolonged and takes place further along the intestinal tract. This in turn delays and spreads the period of glucose absorption, which reduces the extent of the postprandial rise in blood glucose concentrations. The effectiveness of a-glucosidase inhibitors is dq en-dent on the consumption of a meal rich in complex carbohydrate. 

Defensins are a group of antimicrobial and cytotoxic peptides made by immune cells. There are seven defensins in humans, six alpha-defensins and one beta-defensin, which are involved in the innate immune defense at the surface of epithelia from the respiratory tract, the intestinal tract or the urinary tract. 

The dopamine precursor l-DOPA (levodopa) is commonly used in TH treatment of the symptoms of PD. l-DOPA can be absorbed in the intestinal tract and transported across the blood-brain barrier by the large neutral amino acid (LNAA) transport system, where it taken up by dopaminergic neurons and converted into dopamine by the activity of TH. In PD treatment, peripheral AADC can be blocked by carbidopa or benserazide to increase the amount of l-DOPA reaching the brain. Selective MAO B inhibitors like deprenyl (selegiline) have also been effectively used with l-DOPA therapy to reduce the metabolism of dopamine. Recently, potent and selective nitrocatechol-type COMT inhibitors such as entacapone and tolcapone have been shown to be clinically effective in improving the bioavailability of l-DOPA and potentiating its effectiveness in the treatment of PD. 

Constipation, caused by a decrease in intestinal motility, may occur in tiiose taking one of tiiese drag s on a regular basis. Drowsiness may occur widi die use of diese dm, but at times tins adverse reaction is desirable Fbr example when atropine is used preoperatively to reduce die production of secretions in die respiratory tract, drowsiness is part of die desired response... 

Simethicone (Mylicon) and charcoal are used as anti-flatulents (against flatus or gas in the intestinal tract). Simethicone has a defoaming action that disperses and prevents the formation of mucus-surrounded gas pockets in tiie intestine Charcoal is an absorbent that reduces the amount of intestinal gas. 

Human tissues can synthesize purines and pyrimidines from amphibolic intermediates. Ingested nucleic acids and nucleotides, which therefore are dietarily nonessential, are degraded in the intestinal tract to mononucleotides, which may be absorbed or converted to purine and pyrimidine bases. The purine bases are then oxidized to uric acid, which may be absorbed and excreted in the urine. While little or no dietary purine or pyrimidine is incorporated into tissue nucleic acids, injected compounds are incorporated. The incorporation of injected [ H] thymidine into newly synthesized DNA thus is used to measure the rate of DNA synthesis. 

---