Alimentary absorption

Rate constant for alimentary absorption of nickel from the nickel dose (kgi, hour ) 0.28 0.11 0.33 0.24... 

Rate constant for alimentary absorption of dietary nickel intake (kf, pg/hour) 0.092 0.051 0.105 0.036... 

Forfar et al. (F7) have reported the calcium balance in 3 active cases of idiopathic hypercalcemia. The mean calcium intake was 1.02g/day and the mean retention was 49% or 0.45g/day. Morgan et al. (M3) observed retentions of 53 % and 54 % in two cases, the actual daily retentions being 0.46g/day and (on a low calcium intake) 0.31 g/day. These results suggest that there may be some increased calcium retention in idiopathic hypercalcemia. As there is at the same time hypercalcuria without evidence of loss of calcium from bones, the most likely explanation is that there is increased alimentary absorption of calcium. 

Swallowing. If it is sufficiently irritant or caustic, a swallowed material may cause local effects on the mouth, pharynx, esophagus, and stomach. Additionally, carcinogenic materials may induce tumor formation in the alimentary tract. Also, the gastrointestinal tract is an important route by which toxic materials are absorbed. The sites of absorption and factors regulating absorption have been reviewed (42,43). 

Treatment. Treatment of poisoning from soluble barium salts may be preventive or curative (47,51). Preventive treatment involves inhibition of intestinal absorption by administering such soluble sulfates as magnesium or sodium, causing precipitation of barium sulfate in the alimentary tract. 

Nahrungs-aufnahme, /. reception or absorption of food, -bedarf, m. food requirement, -brei, m. chyme, -dotter, m. (Biol.) food yoljc, deutoplasm, -fliissigkeit, /. nutritive liquid chyle, -kanal, m. alimentary canal, -milch, /. (Physiol.) chyle. 

Experiments with rats given oral doses of tritiated food-grade mineral oil provide supporting evidence that the absorption of hydrocarbons in mineral oils is limited. Five hours after dosing with 0.66 mL/kg of tritiated mineral oil ("liquid petrolatum U.S.P."), -75% of the administered radioactivity remained in the alimentary tract, and only 3% of the administered radioactivity was accounted for by radioactivity in other parts of the rat carcass (Ebert et al. 1966). About 80% of the administered radioactivity was recovered in feces during the first 2 days after treatment, and over 90% of the radioactivity in the feces was in the form of mineral oil. These data are consistent with the hypothesis that ingested mineral oil was poorly absorbed. Neither biliary excretion nor enterohepatic circulation of mineral oils was measured in this study, and thus, any quantitative estimates of the extent of absorption based on these data should be viewed as tentative. 

HE Magee, E Reid. (1931). The absorption of glucose from the alimentary canal. J Physiol 73 163-183. 

Surgery, which reduces the stomach volume or absorptive surface of the alimentary tract, remains the most effective intervention for obesity. Although modern techniques are safer than older procedures and have an operative mortality of 1%, there are still many potential complications. Therefore, surgery should be reserved for those with BMI greater than 35 or 40 kg/m2 and significant comorbidity. 

The iron absorption is inhibited in the presence of carbonates, oxalates and phosphates. Probably they participate in macromolecular polymer formation, which are not absorbable from alimentary canal. 

Despite the gastrointestinal absorption characteristics discussed above, it is common for absorption from the alimentary tract to be facilitated by dilution of the toxicant. Borowitz et al. (1971) have suggested that the concentration effects they observed in atropine sulfate, aminopyrine, sodium salicylate, and sodium pentopar-bital were due to a combination of rapid stomach emptying and the large surface area for absorption of the drugs. 

The presence of bile salts in the alimentary tract can affect absorption of potential toxicants in a variety of ways, depending on their solubility characteristics. 

Fecal softeners are substances that are not absorbed from the alimentary canal and act by increasing the bulk of the feces and softening the stool so that it is easier to pass. Mineral oil has been in use for many years, either as the oil or as a white emulsion it is a mixture of liquid hydrocarbons. Its use has been criticized for many reasons. It dissolves the fat-soluble vitamins and prevents their absorption. It is itself absorbed slightly and appears in the mesenteric lymph nodes, and if it is... 

Drugs are administered to animals by parenteral or enteral administration, and topical application. Parenteral administration bypasses the alimentary tract and can be effected by a variety of routes including intravenous, intramuscular, subcutaneous, intraperitoneal, or intrapleural injections inhalation and percuta-neously. In intravenous injections, entry of dmgs into the system depends only upon the rate of injection and not on absorption into the bloodstream. As a result, water-soluble poorly absorbed drugs may be readily administered. 

Absorption of arsenic by the bones also occurs to a considerable extent,6 and their arsenic content, whether death occurs after a few hours or only after some days, may give valuable information where suspicion of poisoning exists. Thus in the case of a man who died 8 days after ingesting the poison, 110 mg. of arsenic were found in the bones, about half being present in the bones of the arms and legs and about 20 per cent, in the flat bones of the skull but in the case of a woman who died after 12 horns, out of a total of 1907 mg. found in the body only 3-2 mg. occurred in the bones,7 but this amount was more than was found in any other portion of the body (except the skin) not in direct contact with the alimentary canal. In experiments on dogs to which arsenic had been administered, Popp showed 8 that the amount of arsenic in the calcined bones was about one-sixth of the amount found in the bones before cremation, and less than one-thousandth of the total amount in the whole body before cremation. 

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