Membrane Permeability in the Gastrointestinal Tract: The Interplay between Microclimate pH and Transporters

2009 ◽  
Vol 6 (11) ◽  
pp. 1923-1932 ◽  
Author(s):  
Albin Kristl
Keyword(s):  
Gastrointestinal Tract ◽  
Membrane Permeability ◽  
Microclimate Ph

scholarly journals Gastrointestinal tract and skin permeability of chemicals in consumer products using parallel artificial membrane permeability assay (PAMPA)

2021 ◽  
Vol 36 (3) ◽  
pp. e2021021
Author(s):  
Juyoung Park ◽  
Handule Lee ◽  
Kwangsik Park
Keyword(s):  
Risk Assessment ◽  
Gastrointestinal Tract ◽  
Membrane Permeability ◽  
Chemical Exposure ◽  
Consumer Products ◽  
Skin Permeability ◽  
Log P ◽  
Lipid Solubility ◽  
Artificial Membrane ◽  
Chemical Structures

Some chemicals commonly used in personal care products, household items, food vessels, cosmetics, and other consumer products are potentially harmful, and several reviews of epidemiological studies have suggested the associations between the chemical exposure from consumer products, and respiratory diseases, skin sensitization, and reproductive problems. Therefore, risk assessment is essential for management of consumer products safety. Necessarily, the estimation of human exposure is an essential step in risk assessment, and the absorption rate of those chemicals via the gastrointestinal tract, respiratory tract, and skin are very critical in determining the internal dose of the exposed chemicals. In this study, parallel artificial membrane permeability assays (PAMPA) for the gastrointestinal tract and skin were performed to evaluate the permeability of parabens (4-hydroxybenzoic acid, methyl-, propyl-, and butyl paraben), bisphenols (bisphenol A, bisphenol F, and bisphenol S), isothiazolinones (methyl-, chloromethyl-, benz-, octyl-, and dichlorooctyl isothiazolinone), and phthalates [diethyl-, dibutyl-, Di-isononyl-, and bis(2-ethylhexyl) phthalate]. Lipid solubility of test chemicals indicated by log P values was shown as the most critical factor and showed a positive association with the permeability of parabens, bisphenols, and isothiazolinones in PAMPA assay. However, phthalate showed a reverse-association between lipophilicity and permeability. The permeability of all the tested chemicals was higher in the gastrointestinal tract membrane than in the skin membrane. The pH in donor solution did not show significant effects on the permeability in all the chemicals, except the chemicals with a free hydrophilic moiety in their chemical structures.

Habitat Association of Klebsiella Species

1985 ◽  
Vol 6 (2) ◽  
pp. 52-58 ◽  
Author(s):  
Susan T. Bagley
Keyword(s):  
Drinking Water ◽  
Gastrointestinal Tract ◽  
Surface Waters ◽  
Industrial Effluents ◽  
Opportunistic Pathogen ◽  
Habitat Associations ◽  
Habitat Association ◽  
Klebsiella Species ◽  
Almost All ◽  
Polluted Waters

AbstractThe genus Klebsiella is seemingly ubiquitous in terms of its habitat associations. Klebsiella is a common opportunistic pathogen for humans and other animals, as well as being resident or transient flora (particularly in the gastrointestinal tract). Other habitats include sewage, drinking water, soils, surface waters, industrial effluents, and vegetation. Until recently, almost all these Klebsiella have been identified as one species, ie, K. pneumoniae. However, phenotypic and genotypic studies have shown that “K. pneumoniae” actually consists of at least four species, all with distinct characteristics and habitats. General habitat associations of Klebsiella species are as follows: K. pneumoniae—humans, animals, sewage, and polluted waters and soils; K. oxytoca—frequent association with most habitats; K. terrigena— unpolluted surface waters and soils, drinking water, and vegetation; K. planticola—sewage, polluted surface waters, soils, and vegetation; and K. ozaenae/K. rhinoscleromatis—infrequently detected (primarily with humans).

Initial Polymerization Sites Indicated During Mitochondrial Oxidation of Diaminobenzidine after Toluene Treatment

1977 ◽  
Vol 35 ◽  
pp. 408-409
Author(s):  
W. A. Shannon ◽  
M. A. Matlib
Keyword(s):  
Membrane Permeability ◽  
Cytochrome Oxidase ◽  
Rat Liver ◽  
Precise Definition ◽  
Cytochemical Localization ◽  
Oxidative Reaction ◽  
Mitochondrial Oxidation ◽  
Definition Of ◽  
Exogenous Substrates

Numerous studies have dealt with the cytochemical localization of cytochrome oxidase via cytochrome c. More recent studies have dealt with indicating initial foci of this reaction by altering incubation pH (1) or postosmication procedure (2,3). The following study is an attempt to locate such foci by altering membrane permeability. It is thought that such alterations within the limits of maintaining morphological integrity of the membranes will ease the entry of exogenous substrates resulting in a much quicker oxidation and subsequently a more precise definition of the oxidative reaction.The diaminobenzidine (DAB) method of Seligman et al. (4) was used. Minced pieces of rat liver were incubated for 1 hr following toluene treatment (5,6). Experimental variations consisted of incubating fixed or unfixed tissues treated with toluene and unfixed tissues treated with toluene and subsequently fixed.

Sarcolemmal permeability changes during early myocardial anoxia

1978 ◽  
Vol 36 (2) ◽  
pp. 642-643
Author(s):  
M. Ashraf ◽  
L. Landa ◽  
L. Nimmo ◽  
C. M. Bloor
Keyword(s):  
Cell Membrane ◽  
Membrane Permeability ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Cell Membrane Permeability ◽  
Enzyme Release ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Sarcolemmal Permeability ◽  
Membrane Changes

Following coronary artery occlusion, the myocardial cells lose intracellular enzymes that appear in the serum 3 hrs later. By this time the cells in the ischemic zone have already undergone irreversible changes, and the cell membrane permeability is variably altered in the ischemic cells. At certain stages or intervals the cell membrane changes, allowing release of cytoplasmic enzymes. To correlate the changes in cell membrane permeability with the enzyme release, we used colloidal lanthanum (La+++) as a histological permeability marker in the isolated perfused hearts. The hearts removed from sprague-Dawley rats were perfused with standard Krebs-Henseleit medium gassed with 95% O2 + 5% CO2. The hypoxic medium contained mannitol instead of dextrose and was bubbled with 95% N2 + 5% CO2. The final osmolarity of the medium was 295 M osmol, pH 7. 4.

Keratinocyte growth factor binds to collagens of the gastrointestinal tract: Identification of the collagen binding structure

2001 ◽  
Vol 120 (5) ◽  
pp. A695-A695
Author(s):  
M RUEHL ◽  
I SCHOENFELDER ◽  
R FARNDALE ◽  
G KNIGHT ◽  
R SOMASUNDARAM ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Growth Factor ◽  
Keratinocyte Growth Factor ◽  
Collagen Binding ◽  
Binding Structure

Culture Studies of the Gastrointestinal Tract with a Newly Devised Capsule

1963 ◽  
Vol 45 (5) ◽  
pp. 625-632 ◽  
Author(s):  
Margot Shiner ◽  
T.E. Waters ◽  
J.D. Allan Gray ◽  
R.A. Lambert
Keyword(s):  
Gastrointestinal Tract ◽  
Culture Studies
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