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

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.

In Vitro Measurement of Amino-Acid Uptake by the Human Small Intestine

Pharmacology ◽  
1964 ◽  
Vol 10 (3) ◽  
pp. 157-163 ◽  
Author(s):  
J.W.L. Robinson ◽  
F. Taminelli ◽  
J.P. Felber ◽  
P. Magnenat
Keyword(s):  
Small Intestine ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Human Small Intestine

scholarly journals Measurement of rapidly available glucose (RAG) in plant foods: a potential in vitro predictor of the glycaemic response

1996 ◽  
Vol 75 (3) ◽  
pp. 327-337 ◽  
Author(s):  
Hans N Englyst ◽  
Jan Veenstra ◽  
Geoffrey J Hudson
Keyword(s):  
Small Intestine ◽  
Direct Calculation ◽  
Simple Calculation ◽  
Glycaemic Index ◽  
Equal Weight ◽  
Glycaemic Response ◽  
Human Small Intestine ◽  
Reference Amount

AbstractThe glycaemic index (GI) is an in vivo measurement based on the glycaemicresponse to carbohydrate-containing foods, and allows foods to be ranked on the basis of the rate of digestion and absorption of the carbohydrates that they contain. GI values are normalizedto a reference amount of available carbohydrate and do not reflect the amounts of carbohydrate normally present in foods; for example, a food with a low content of carbohydrates will have a high GI value if that carbohydrate is digested and absorbed rapidly in the human small intestine. This is potentially confusing for a person wishing to control his or her blood glucoselevels by the choice of foods. The rate and extent of starch digestion in vitro has been measured using a technique that classifies starch into three major fractions: rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS). In addition, thistechnique gives a value for rapidly available glucose (RAG), which includes RDS, free glucose and the glucose moiety of sucrose. When the values for thirty-nine foods were expressed on the basis ofthe available carbohydrate content of these foods, highly significant (P<0·001) positive correlations were observed between GI and both RDS and RAG. The measurement of RAGin vitro provides values for direct calculation of the amount of glucose likely to be rapidly absorbed in the human small intestine and,thus, to influence blood glucose and insulin levels. These values can be used to compare foods, as eaten,on an equal-weight basis. Food-table RAG values would allow simple calculation of the total amount of RAG provided by single foods, by whole meals and by whole diets. Studies are planned in which RAG and the glycaemic response in man will be measured for identical food products.

scholarly journals DES2 protein is responsible for phytoceramide biosynthesis in the mouse small intestine

2004 ◽  
Vol 379 (3) ◽  
pp. 687-695 ◽  
Author(s):  
Fumio OMAE ◽  
Masao MIYAZAKI ◽  
Ayako ENOMOTO ◽  
Minoru SUZUKI ◽  
Yusuke SUZUKI ◽  
...  
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Intestinal Epithelial ◽  
Vitro Assay ◽  
Peptide Antibody ◽  
Mouse Small Intestine ◽  
Mrna Content ◽  
Crypt Cells

The C-4 hydroxylation of sphinganine and dihydroceramide is a rate-limiting reaction in the biosynthesis of phytosphingolipids. Mouse DES1 (MDES1) cDNA homologous to the Drosophila melanogaster degenerative spermatocyte gene-1 (des-1) cDNA leads to sphingosine Δ4-desaturase activity, and another mouse homologue, MDES2, has bifunctional activity, producing C-4 hydroxysphinganine and Δ4-sphingenine in yeast [Ternes, Franke, Zahringer, Sperling and Heinz (2002) J. Biol. Chem. 277, 25512–25518]. Here, we report the characterization of mouse DES2 (MDES2) using an in vitro assay with a homogenate of COS-7 cells transfected with MDES2 cDNA and N-octanoyl-sphinganine and sphinganine as substrates. MDES2 protein prefers dihydroceramide as a substrate to sphinganine, and exhibits dihydroceramide Δ4-desaturase and C-4 hydroxylase activities. MDES2 mRNA content was high in the small intestine and abundant in the kidney. In situ hybridization detected signals of MDES2 mRNA in the crypt cells. Immunohistochemistry using an anti-MDES2 peptide antibody stained the crypt cells and the adjacent epithelial cells. These results suggest that MDES2 is the dihydroceramide C-4 hydroxylase responsible for the biosynthesis of enriched phytosphingoglycolipids in the microvillous membranes of intestinal epithelial cells.

scholarly journals Long-Lived Plasma Cells from Human Small Intestine Biopsies Secrete Immunoglobulins for Many Weeks In Vitro

2011 ◽  
Vol 187 (6) ◽  
pp. 2867-2874 ◽  
Author(s):  
Luka Mesin ◽  
Roberto Di Niro ◽  
Keith M. Thompson ◽  
Knut E. A. Lundin ◽  
Ludvig M. Sollid
Keyword(s):  
Small Intestine ◽  
Plasma Cells ◽  
Human Small Intestine
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