Digestive tract

Colonies of bacteria that live in then digestive tract consume cellulose and in the process convert it to other substances that the animal can digest... 

Oral adrninistration of vacciaes may be ineffective as many vacciaes are deactivated in the digestive tract of the animals the vacciaes are intended to protect. Dip treatment by which the vacciaes enter the animals through diffusion from the water are not generally as effective as injection but can be used to vaccinate large numbers of animals in short periods of time. 

DHBs are rapidly absorbed through the digestive tract. Their absorption through skin is low in aqueous solution but may be increased in suitable... 

The LC q (lowest possible lethal concentration) has been reported to be 23 ppm for a 30 min exposure time (mouse), 53 ppm for an exposure time of 100 min (rat, rabbit, and guinea pig), and 200 ppm for an exposure time of 10 min (monkey). No toxic effects were reported upon exposure to 1 ppm for 7 h/d over 55 days. The oral LD q (rat) of ketene is 1300 mg/kg, the low level of toxicity probably being due to the almost immediate formation of acetic acid and other acetates in the digestive tract. 

Lead enters the body through inhalation and ingestion, is absorbed into the circulatory system from the lungs and digestive tract, and excreted via the urine and feces. Normally, intake of lead approximately equals output. However, excessive exposure and intake can cause tissue concentrations to increase to the point where illness can result. 

The particle size and chemical composition of lead and lead compounds affect the readiness with which lead is absorbed from the lungs and digestive tract (see Lead compounds, industrial toxicology). Larger particles and compounds having low aqueous solubiHty are less hazardous than finely divided particles and compounds of higher solubiHty. 

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. 

CCK is found in the digestive tract and the central and peripheral nervous systems. In the brain, CCK coexists with DA. In the peripheral nervous system, the two principal physiological actions of CCK are stimulation of gaU. bladder contraction and pancreatic enzyme secretion. CCK also stimulates glucose and amino acid transport, protein and DNA synthesis, and pancreatic hormone secretion. In the CNS, CCK induces hypothermia, analgesia, hyperglycemia, stimulation of pituitary hormone release, and a decrease in exploratory behavior. The CCK family of neuropeptides has been impHcated in anxiety and panic disorders, psychoses, satiety, and gastric acid and pancreatic enzyme secretions. 

Oral Toxicity. Alkan olamines generally have low acute oral toxicity, but swallowing substantial quantities could have serious toxic effects, including injury to mouth, throat, and digestive tract. 

Concentrated monoethan olamine and monoisopropan olamine can cause severe local irritation or even bums to the mouth, throat, and digestive tract. If monoethan olamine and monoisopropan olamine are swallowed, large volumes of milk or water should be administered immediately. If diethanolamine, triethanolamine, diisopropanolamine, or triisopropanolamine are swallowed, vomiting should be induced after drinking two glasses of water. 

Beef tapeworm (Taenia saginatd) is found worldwide in people who eat rare beef and is most common in developing countries. Worms are often 5—10 m long with about 1000 proglottides. Usually a patient carries only one worm. Infected persons are frequently asymptomatic, but intestinal disturbances can occur. Detached sections of worm 0.5 cm x 2 cm may creep out of the end of the digestive tract. 

The filariform larva found in moist soils may be either ingested or penetrate the skin of its host. It is then carried through the circulatory system to the lungs and migrates up the respiratory tree into the digestive tract. The worms feed on intestinal tissue and blood. Some worms may persist in humans as long as nine years. Infestations cause cutaneous reactions, pulmonary lesions, intestinal ulcerations, and anemia. 

Flucytosine [2022-85-7] is well absorbed in the digestive tract, which is why oral adraiinistration is preferable. Plasma levels of 30 —40 mg/L are obtained after a dose of 30 mg/kg body weight. Approximately 90% of the pyrimidine derivative is found unaltered in urine, indicating that it is highly suitable for the treatment of renal candidosis. High concentrations were also noted in cerebrospinal fluid the average concentration is approximately 75% of the plasma concentration. 

Historically, dietary fiber referred to iasoluble plant cell wall material, primarily polysaccharides, not digested by the endogenous enzymes of the human digestive tract. This definition has been extended to iaclude other nondigestible polysaccharides, from plants and other sources, that are iacorporated iato processed foods. Cellulose [9004-34-6] (qv) is fibrous however, lignin [9005-53-2] (qv) and many other polysaccharides ia food do not have fiberlike stmctures (see also Carbohydrates). 

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). 

Unlike many of the catalysts that chemists use in the laboratory, enzymes are usually specific in their action. Often, in tact, an enzyme will catalyze only a single reaction of a single compound, called the enzyme s substrate. For example, the enzyme amylase, found in the human digestive tract, catalyzes only the hydrolysis of starch to yield glucose cellulose and other polysaccharides are untouched by amylase. 

Animals, including humans, cannot synthesise all the different amino adds they need and thus require them in their diet. These amino adds are called the essential amino acids. Proteins in food are hydrolysed in the digestive tract and the resulting amino acids are reassembled into proteins within the animal s cells. All animals are ultimately dependent on plants for protein, as it is plants that create protein by combining inorganic nitrogen from the soil (as nitrate) with organic molecules derived from carbon from the atmosphere (as CO2). 

The first step of a chemical study should be the quantitative measurements of coelenterazine, dehydrocoelenterazine, and a coelenter-azine-specific luciferase, in the light organs, liver, digestive tract (with empty stomach), and eggs if available (see Section C5 of Appendix for the method). A clear, unequivocal presence of a coelenterazine luciferase indicates the involvement of a luciferin-luciferase system,... 

---