Uptake and Absorption

Uptake and Absorption After oral administration of NiCl2 or NiClj to fasting rats or mice, 3-6% of the radiolabeled Ni is absorbed from the intestinal tract (Ho and Furst 1973, Nielsen 

In addition to gastrointestinal absorption, nickel may also enter the body by inhalation, transcutaneous absorption, and parenteral administration. In humans, approximately 35% of inhaled nickel is absorbed from the respiratory tract the remainder is carried up the tracheobronchial mucociliary escalator and either swallowed or expectorated (Bennett 1984, Grandjean 1984, Sunderman 1986b). In penetration through the epidermis, nickel may be bound to urocanic acid and histidine, which occur in human sweat (Mali etal. 1964). Hostynek etal. 

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Fuels such as diesel and kerosene readily absorb hydrocarbon vapors, the total uptake and absorption rate depending on both chemical and physical factors. If a soluble test gas is introduced above a charged test oil the concentration of flammable test gas therefore decreases with time. Liquid mist and spray produced by charged liquid increase the absorption rate relative to a quiescent liquid surface. As discussed in A-5-4, absorption could lead to an underestimation of test gas MIE near the liquid surface unless the rate of test gas introduction is sufficiently high to offset the rate of removal. Table 3-8.1.2 shows solubilities of a selection of gases in a mineral-based transformer oil at ambient temperature and pressure [200]. 

Roughead, Z.K., Zito, C. A., and Flunt, J. R. (2002). Initial uptake and absorption of nonheme iron and absorption of heme iron in humans are unaffected by the addition of calcium as cheese to a meal with high iron bioavailability. Am. ]. Clin. Nutr. 76, 419 25. 

Rapid-acting insulin analogues (lispro, insulin aspart [Humalog, Novo log]) have been engineered to contain amino acid modifications that promote rapid entry into the circulation from subcutaneous tissue. They begin to exert their effects as early as 5 to 10 minutes after administration. Lispro insulin, the first insulin analogue to be approved in Europe and the United States, is produced by switching the positions of lysine-proline amino acid residues 28 and 29 of the carboxy terminus of the p-chain. Lispro insulin displays very similar actions to insulin and has a similar affinity for the insulin receptor, but it cannot form stable hexamers or dimers in subcutaneous tissue, which promotes its rapid uptake and absorption. 

Table 1.3 Examples of interactions of chemicals at the uptake and absorption level in humans...

Bonewitz RF, Voner C, Foulkes EC. 1982. Uptake and absorption of zinc in perfused rat jejunum The role of endogenous factors in the lumen. Nutrition Research 2 301-307. 

The complete picture of uptake from food is unclear. Fixation by acidic soils appears to be a major factor [47], while the amount of Se in plants does not predict its uptake and absorption by humans [10]. However, on the basis of the large volume of research performed, the Food and Nutrition Board (United States) proposed a safe range of50-200 p.g/day Se intake for adults [48]. In countries where soils are Se-deficient, supplementation of the soil or animal feedstuOls is employed. 

Awad WA, Aschenbach JR, Setyabudi FM, Razzazi-Fazeli E, Bohm J, Zentek J. In vitro effects of deoxynivalenol on small intestinal D-glucose uptake and absorption of deoxynivalenol across the isolated jejunal epithelium of laying hens. Poult Sci. 2007 86 15-20. 

After oral uptake and absorption of the PAs (Scheme 13.3 la and Ib), a hydroxyl-group is introduced adjacent to the nitrogen atom in the necine (position 3 or 8) by the cytochrome P-450 monoxogenase enzyme complex in the liver (Scheme 13.3 Ila and Ilb). 

Blood lead values in childhood vary with age and differ from those of adults living in the same environment. Conventional metabolic balance studies in children have limitations for the study of factors modifying lead absorption. Feeding studies, and the use of both isolated and in-vivo gut loops in laboratory animals have shown that major minerals, lipids and proteins, modify lead uptake and absorption. Intrinsic ma-turational changes modify the response to ingested lead and are relat-... 

Figure 44-2. Digestion and absorption of triacylglycerols.The values given for percentage uptake may vary widely but indicate the relative importance of the three routes shown.

In contrast to previous in vivo models, this in vitro model provides the possibility of dissociating experimentally two important processes of intestinal absorption cellular uptake and secretion. Under conditions mimicking the postprandial state (taurocholate/oleic acid supplementation), differentiated Caco-2 cells were able to (1) take up carotenoids at the apical sides and incorporate them into CMs and (2) secrete them at the basolateral sides associated with CM fractions. Using this approach, the extent of absorption of P-carotene through Caco-2 cell monolayers after 16 hr of incubation was 11.2%, a value falling within the in vivo range (9 to 22%). ° - Of the total amount of P-carotene secreted, 78% was associated with the two CM fractions and 10% with the VLDL fraction. ... 

Two studies have used single cells to study the effect of phenolic acids on mineral absorption. In sterile cell cultures of Paul s Scarlet rose, 100 pM ferulic acid inhibited Rb+ absorption in about 10 min when the cells were 4-5 days old (37). Uptake from 0.2 mM RbCl was inhibited about 25% and absorption from 5.0 mM RbCl was inhibited 45%. Absorption by 10-day-old cells was affected little. Salicylic acid at 10 pM inhibited PO - absorption by Scenedesmus, a unicellular green alga (38). These studies show that allelochemicals inhibit mineral absorption in cellular systems as well as tissue systems (Table I). 

Water uptake has been implicated as a mechanism of action for tablet disintegrants. Khan and Rhodes studied the adsorption and absorption properties of various disintegrants [56]. They concluded that the... 

Wang, X. D., N. I. Krinsky, R. P. Marini et al. 1992. Intestinal uptake and lymphatic absorption of beta-carotene in ferrets A model for human beta-carotene metabolism. Am J Physiol 263(4Pt 1) G480-G486. 

The peculiar thing in hereditary haemochromatosis (HH) is that the intestinal mucosal cell behaves essentially like an iron deficient cell. Iron absorption is always high if related to the body s iron needs. In HH subjects with normal plasma ferritin values, both mucosal uptake and mucosal transfer of iron often exceed values found in patients with uncomplicated iron deficiency (Marx, 1979b). In fact the situation with respect to iron absorption in mature intestinal mucosal cells, as depicted in Figure 9.4(b), is identical to that in iron deficiency, except for the difference in plasma iron saturation. It was already known that mucosal cells in HH contain no ferritin, explaining the high mucosal transfer of iron (Francanzani... 

Uptake and transport of the ACE-inhibitor ceronapril (SQ 29852) by monolayers of human intestinal absorptive (Caco-2) cells in vitro, Int. 

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