Castanospermine inhibits glucosidase I and glycoprotein secretion in human hepatoma cells.

We studied the effect of the plant alkaloid castanospermine on the biosynthesis and secretion of human hepatoma glycoproteins. The HepG-2 cells, grown in the presence or absence of the alkaloid, were labelled with [2-3H]mannose and then the labelled glycopeptides were prepared by Pronase digestion. This material was analysed by gel filtration on Bio-Gel P-4 before and after treatment with endo-beta-N-acetylglucosaminidase H.

Folic acid uptake characteristics of a human colon carcinoma cell line, Caco-2. A newly-described cellular model for small intestinal epithelium.

To investigate a newly described model for differentiated small intestinal function, folic acid uptake characteristics were examined in the human colon carcinoma cell line, Caco-2. Monolayers of this cell line spontaneously exhibit structural and functional differentiation patterns characteristic of mature enterocytes, with the appearance of brush border microvilli and high activity levels of the enzymes associated with the brush border. Our results concur with other models of folic acid uptake that emphasize the importance of intraluminal factors on micronutrient absorption.

Isolation of alpha 1-acid glycoprotein from human plasma using high-performance liquid chromatography.

A method for the rapid isolation of purified alpha 1-acid glycoprotein (AGP) from small volumes of human plasma using HPLC has been developed. The method involves preparation of the seromucoid fraction of plasma by sequential perchloric acid and phosphotungstic acid precipitations, followed by chromatography on an HPLC TSKG-3000 column. The yield was high (0.