In vitro uptake

Phloretin inhibits FATP-mediated traversing of fatty acids across lipid bilayers. Phloretin is the aglycon of phlorizin and has been used to terminate the uptake of LCFAs and VLCFAs in timed in vitro uptake assays with cultured cells or in ex vivo uptake assays with isolated primary cells. 

Allen JW, Shanker G, Aschner M. 2001. Methyhnercury inhibits the in vitro uptake of the glutathione precursor, cystine, in ashocytes, but not in neurons. Brain Res 894 131-140. 

Fetterer, R.H. and Rhoads, M.L. (1997) The in vitro uptake and incorporation of haemoglobin by adult Haemonchus contortus. Veterinary Parasitology 69, 77—87. 

The overall distribution of lanthanides in bone may be influenced by the reactions between trivalent cations and bone surfaces. Bone surfaces accumulate many poorly utilized or excreted cations present in the circulation. The mechanisms of accumulation in bone may include reactions with bone mineral such as adsorption, ion exchange, and ionic bond formation (Neuman and Neuman, 1958) as well as the formation of complexes with proteins or other organic bone constituents (Taylor, 1972). The uptake of lanthanides and actinides by bone mineral appears to be independent of the ionic radius. Taylor et al. (1971) have shown that the in vitro uptakes on powdered bone ash of 241Am(III) (ionic radius 0.98 A) and of 239Pu(IV) (ionic radius 0.90 A) were 0.97 0.016 and 0.98 0.007, respectively. In vitro experiments by Foreman (1962) suggested that Pu(IV) accumulated on powdered bone or bone ash by adsorption, a relatively nonspecific reaction. On the other hand, reactions with organic bone constituents appear to depend on ionic radius. The complexes of the smaller Pu(IV) ion and any of the organic bone constituents tested thus far were more stable (as determined by gel filtration) than the complexes with Am(III) or Cm(III) (Taylor, 1972). 

Maliwal BP, Guthrie FE. 1982. In vitro uptake and transfer of chlorinated hydrocarbons among human lipoproteins. J Lipid Res 23(3) 474-479. 

Poelma DL, Zimmermann LJ, Scholten HH, et al. In vivo and in vitro uptake of surfactant lipids by alveolar type II cells and macrophages. Am J Physiol Lung Cell Mol Physiol 2002 283(3) L648-L654. 

For a better idea of the toxicity of VOCs, we can look more closely at some studies of TCE (Bogen et al., 1998). In vitro uptake of C-14-labeled trichloroethylene (TCE) from dilute (similar to 5-ppb) aqueous solutions into human surgical skirt was measured using accelerator mass spectrometry (AMS). The AMS data obtained positively correlate with (p approximate to 0) and vary significantly nonlinearly with (p = 0.0094) exposure duration. These data are inconsistent (p approximate to 0) with predictions made for TCE by a proposed EPA dermal exposure model, even when uncertainties in its recommended parameter values for TCE are considered but are consistent (p = 0.17) with a 1-compartment model for exposed skin-surface. This study illustrates the power of AMS to facilitate analyses of contaminant biodistribution and uptake kinetics at very low environmental concentrations. Eurther studies could correlate this with toxicity. 

Coester, C., Nayyar, R, and Samuel, J. (2006), In vitro uptake of gelatin nanoparticles by murine dendritic cells and their intracellular localisation, Eur. J. Pharm. Biopharm., 62(3), 306-314. 

Fig. 29. A structural model of the steps involved in the in vitro uptake of iron by transferrins, shown for one lobe. ( ) Iron ( ) carbonate Y, Tyr ligands H, His ligand D, Asp ligand (O) chelate ligands. The positive charge at the anion site is due to the helix N-terminus and the Arg side chain. (Note that this is for the case in which Fe3+ is added as a chelate complex.)...

Berndt WO, Koschler F. in vitro uptake of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4, 5-trichlorophenoxyacetic acid (2,4, 5-T) by renal cortical tissue of rabbits and rats. Toxicol AppI Pharmacol 1973 26 559-570. 

Thompson ABR, Keelan M, Clandinin MT. Feeding rats a diet enriched with saturated fatty acids presents the inhibitory effects of acute and chromic ethanol exposure on the in vitro uptake of hexoses and lipids. Biochem Biophys Acta 1991 1084 122-128. 

Structural similarities can be seen, however, when the hydropathy profiles of the tobacco and Arabidopsis ALS transit peptides are compared (not shown). This suggests that a functional transit sequence depends more on secondary or higher order structural constraints than on primary sequence information. The in vitro uptake system described above can be used to further investigate the transit peptide domain. 

A detailed investigation of the effect of micellar solubilization on the transport of lipids has been made by Westergaard and Dietschy [59]. They studied in vitro uptake of lipids into rabbit intestinal disks by varying the proportions of lipid and bile salts in mixed micelles in 3 different ways. Either lipid concentration was increased with bile salts kept at a constant level, lipid concentration was unchanged while bile salt concentration was varied, or both lipid and bile salt concentration was increased with the molar ratio kept constant. Theoretical calculations of how the mass of the lipid probe was distributed between the aqueous and the micellar compartment showed that there was a good correlation between calculated aqueous monomer concentration and experimentally obtained values for lipid uptake. The rate of uptake is thus proportional to the aqueous monomer concentration of a particular lipid. The conclusion drawn was that diffusion of the lipid molecules in monomeric form through the aqueous phase is an obligatory step before uptake into the plasma membrane, and that the role of bile salt is therefore to overcome the resistance of the unstirred water layer by micellar solubilization. 

Poet TS, Borghoff SJ (1997) In vitro uptake of methyl tert-butyl ether in male rat kidney use of a two-compartment model to describe protein interactions. Toxicol Appl Pharmacol 145 340-348... 

Fisher SE, Atkinson M, Chang B. 1987. Effect of delta-9-tetrahydrocannabinol on the in vitro uptake of alpha-amino isobutyric acid by term human placental slices. Pediatr Res 21 104—107. 

Brown, R.C., Fleming, G.T., and Knight, A.I., Asbestos affects the in vitro uptake and detoxification of aromatic compounds. Environ. Health Perspect, 51, 315-318, 1983. 

Khalil SAH, Iwuagwu M. The in vitro uptake of some oral contraceptive steroids by magnesium trisilicate. JPharm Pharmacol( 976) 28 (Suppl), 47P. 

Karlgard, C.C.S. Wong, N.S. Jones, L.W. Moresoli, C. in vitro uptake and release studies of ocular pharmaceutical agents by silicon-containing and p-HEM A hydrogel contact lenses. Int. J. Pharm. 2003, 257 (1), 141-151. 

Bruun A., Ehinger B, and Forsberg A. (1974) In vitro uptake of p-alanine into rabbit retinal neurons. Exp. Brain Res. 19, 239-247. 

In another example, a hydrophilic star block copolymer was composed of a hyperbranched PEI core, a PLL inner shell and a PEG outer shell. Insulin, as a model protein, can be rapidly and efficiently encapsulated by the synthesized polymer in aqueous phosphate buffer at physiological pH. Complexation between PEI-PLL-Z)-PEG and insulin was demonstrated using native polyacrylamide gel electrophoresis. An in vitro release study by dialysis showed sustained release of the encapsulated protein at physiological pH, and an accelerated release when the pH was decreased. The insulin released from the star block copolymer retained its chemical integrity and immu-nogenicity. Successful in vitro uptake studies of enhanced green fluorescent protein into Ad293 cells mediated by PEI-PLL-Z)-PEG were also performed. ... 

Gao Y, Zhang Z, Chen L, Gu W, Li Y. Chitosan N-bettiinates/DNA self-assembly nanoparticles for gene delivery In vitro uptake and transfection efficiency. Int J Pharm. 2009 371(l-2) 156-62. 

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