Miniaturized Transfer Models to Predict the Precipitation of Poorly Soluble Weak Bases upon Entry into the Small Intestine

An improvement in the usual procedure for estimating cellular H+ gradients by distribution of weak bases is described, which involves evaluation of and correction for the permeability of the ionic form of the sensor. In the case of methylamine, unidirectional uptake (influx) of the methylammonium ion is calculated by comparing the total influx of [14C]methylamine with the influx of the highly permeant ion [14C]tetraphenyl-phosphonium ([14C]TPP+) for two experimental situations in which the membrane potential differs. Comparison of the potential-dependent changes in unidirectional influx of methylamine and TPP+ allows calculation of the magnitude of influx for the methylammonium ion. This value can then be used to determine the error in the H+ gradient as estimated from the steady-state distribution of methylamine across the plasma membrane. By using ATP-depleted isolated small intestine cells from the chick as the test system, and imposed H+ gradients of defined magnitude, it can be shown that the observed error matches the calculated error.

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Precipitation in and Supersaturation of Contents of the Upper Small Intestine After Administration of Two Weak Bases to Fasted Adults

Pharmaceutical Research ◽

10.1007/s11095-011-0506-6 ◽

2011 ◽

Vol 28 (12) ◽

pp. 3145-3158 ◽

Cited By ~ 140

Author(s):

Dimitrios Psachoulias ◽

Maria Vertzoni ◽

Konstantinos Goumas ◽

Vasilios Kalioras ◽

Stefania Beato ◽

...

Keyword(s):

Small Intestine ◽

Weak Bases

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Relations of weak-electrolyte transport and acid-base metabolism in rat small intestine in vitro

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1975.228.2.482 ◽

1975 ◽

Vol 228 (2) ◽

pp. 482-487 ◽

Cited By ~ 26

Author(s):

MJ Jackson ◽

BN Morgan

Keyword(s):

Small Intestine ◽

Electrolyte Transport ◽

Metabolic Inhibitors ◽

Rat Small Intestine ◽

Acid Base ◽

Compartment System ◽

Weak Electrolyte ◽

Weak Bases ◽

Proposed Model

The jejunal and ileal regions of rat small intestine in vitro exhibit different patterns of weak-electrolyte transport and acid-base metabolism. The jejunal pattern of weak-electrolyte transport is net transport of weak acids M yields S and of weak bases S yields M (M, mucosal; S, serosal), and the pattern of acid-base metabolism is luminal acidification and serosal alkalinization. In the absence of sodium or in the presence of metabolic inhibitors, weak-electrolyte transport and serosal alkalinization are inhibited, but luminal acidification is not inhibited. The ileal pattern of weak-electrolyte transport is the opposite of that of the jejunum and may be associated with the presence of a luminal alkalinization process observed in this region. In the absence of chloride the ileal patterns of weak-electrolyte transport and acid-base metabolism become similar to those of the jejunum. It is suggested that these observations support a previously proposed model for weak-electrolyte transport in the intestine consisting of a series three-compartment system in which the pH of the intermediate compartment is greater than that of the bulk phases.

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An In Vitro Methodology for Forecasting Luminal Concentrations and Precipitation of Highly Permeable Lipophilic Weak Bases in the Fasted Upper Small Intestine

Pharmaceutical Research ◽

10.1007/s11095-012-0844-z ◽

2012 ◽

Vol 29 (12) ◽

pp. 3486-3498 ◽

Cited By ~ 68

Author(s):

Dimitrios Psachoulias ◽

Maria Vertzoni ◽

James Butler ◽

David Busby ◽

Moira Symillides ◽

...

Keyword(s):

Small Intestine ◽

Weak Bases

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Electron probe x-ray microanalysis and electron microscopy of amino acid absorption and transport by the small intestine: inhibition by chemical poisons and correlation to the elemental composition of the epithelial cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100142311 ◽

1986 ◽

Vol 44 ◽

pp. 134-135

Author(s):

A. J. Tousimis

Keyword(s):

Small Intestine ◽

Amino Acid ◽

Epithelial Cells ◽

Elemental Composition ◽

Isotope Labeling ◽

Structural Components ◽

X Ray ◽

Human Small Intestine ◽

Transport Studies

The elemental composition of amino acids is similar to that of the major structural components of the epithelial cells of the small intestine and other tissues. Therefore, their subcellular localization and concentration measurements are not possible by x-ray microanalysis. Radioactive isotope labeling: I131-tyrosine, Se75-methionine and S35-methionine have been successfully employed in numerous absorption and transport studies. The latter two have been utilized both in vitro and vivo, with similar results in the hamster and human small intestine. Non-radioactive Selenomethionine, since its absorption/transport behavior is assumed to be the same as that of Se75- methionine and S75-methionine could serve as a compound tracer for this amino acid.

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The protease phenotype and crystalline nature of the granules of intraepithelial mast cells in Trichinella spiralis-infected mice

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100140464 ◽

1995 ◽

Vol 53 ◽

pp. 818-819

Author(s):

D.S. Friend ◽

N. Ghildyal ◽

M.F. Gurish ◽

K.F. Austen ◽

R.L. Stevens

Keyword(s):

Small Intestine ◽

Mast Cells ◽

Epithelial Cells ◽

Lamina Propria ◽

Trichinella Spiralis ◽

Intestinal Epithelial ◽

Carboxypeptidase A ◽

C3h Mice ◽

Granule Morphology ◽

Crystalline Nature

Trichinella spiralis induces a profound mastocytosis and eosinophilia in the small intestine of the infected mouse. Mouse mast cells (MC) store in their granules various combinations of at least five chymotryptic chymases [designated mouse MC protease (mMCP) 1 to 5], two tryptic proteases designated mMCP-6 and mMCP-7 and an exopeptidase, carboxypeptidase A (mMC-CPA). Using antipeptide, protease -specific antibodies to these MC granule proteases, immunohistochemistry was done to determine the distribution, number and protease phenotype of the MCs in the small intestine and spleen 10 to >60 days after Trichinella infection of BALB/c and C3H mice. TEM was performed to evaluate the granule morphology of the MCs between intestinal epithelial cells and in the lamina propria (mucosal MCs) and in the submucosa, muscle and serosa of the intestine (submucosal MCs).As noted in the table below, the number of submucosal MCs remained constant throughout the study. In contrast, on day 14, the number of MCs in the mucosa increased ~25 fold. Increased numbers of MCs were observed between epithelial cells in the mucosal crypts, in the lamina propria and to a lesser extent, between epithelial cells of the intestinal villi.

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