There is marked variation in the quality of the Web sites containing information on Crohn's disease and ulcerative colitis. Many Web sites suffered from poor quality but there were five high-scoring Web sites.
The expression of the putative membrane fatty-acid transporter (FAT) was investigated in the small intestine. The FAT mRNA level was higher in the jejunum than in the duodenum and was lower in the ileum, as observed for cytosolic fatty-acid-binding proteins (FABP) expressed in this tissue. No FAT transcript was found in the stomach or colon. FAT mRNA was constitutively expressed i n the epithelial cells located in the upper two thirds of villi, while it was undectectable in the crypt cells and submucosal cells. In jejunal mucosa, immunochemical studies showed that FAT protein was limited to the brush border of enterocytes. No fluorescence was found in the goblet cells. To determine whether FAT responded to changes in fat intake, as reported for FABP, the effect of two high-fat diets, which essentially contained either medium-chain fatty acids or long-chain fatty acids (sunflower-oil diet), was investigated. The sunflower-oil diet greatly increased FAT mRNA abundance throughout the small intestine. In contrast, a weak effect of medium-chain fatty acids was observed only in the jejunum. As found for FABP expression, treatment with the hypolipidemic drug bezafibrate affected FAT expression. These data demonstrate that FAT and FABP are co-expressed in enterocytes, as has been shown in adipocytes, myocytes and mammary cells. The data suggest that these membrane and cytosolic proteins might have complementary functions during dietary-fat absorption.Keywords: fatty-acid transporter ; fatty-acid-binding protein ; small intestine ; gene regulation ; lipid.How long-chain fatty acids (LCFA) move across the biological membranes is subject to controversy. Because of their lipophilic character, they were expected to diffuse freely through the plasma membrane of cells [I]. However, this concept was challenged by the finding of a rapid and saturable uptake, which was reduced by prior heat denaturation or protease treatment of cells 121, and by the isolation and characterization of several plasma-membrane proteins that showed high affinity for LCFA [2-51. The small intestine might express at least two of these proteins: the plasma-membrane fatty-acid-binding protein (FABP) and the fatty-acid transporter (FAT) [6]. The plasmamembrane FABP is a 40-kDa protein postulated to mediate fatty acid uptake through an active sodium-dependent process in the gut 17, 81. The regulation of this protein is unknown since it has not been cloned. FAT is a 88-kDa membrane protein, which was cloned recently in adipocytes, where it might be involved in the sequestration and uptake of fatty acids 191. This protein, which is similar to the CD36 glycoprotein [lo], was detected by means of Northern blot analysis in various tissues including the small intestine [9].Once within the cell, LCFA bind to 14-1 5-kDa cytosolic proteins termed fatty-acid-binding proteins (FABP), which are thought to be involved in facilitation of LCFA desorption from the plasma membrane and diffusion of LCFA through the cytosol [ll]. Several recent reports showed that the express...
Summary ― Essential fatty acids (EFA), which are not synthesized in animal and human tissues, belong to the n-6 and n-3 families of polyunsaturated fatty acids (PUFA), derived from linoleic acid (LA,) and a-linolenic acid (LNA,. Optimal requirements are 3-6% of ingested energy for LA and 0.5-1% for LNA in adults. Requirements in LNA are higher in development. Dietary sources of LA and LNA are principally plants, while arachidonic acid (AA,) is found in products from terrestrian animals, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)
Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine.
The effects of dietary oil intake and fatty acid infusions on the expression of intestinal and liver fatty acid-binding proteins (I-FABP and L-FABP, respectively) were investigated in the small intestine of mice. A daily force-feeding for 7 days with 0.2 ml sunflower oil specifically increased L-FABP mRNA and protein levels in duodenum and proximal jejunum. This upregulation was mediated in time- and dose-dependent manners by a minute quantity of linoleic acid, the main fatty acid found in sunflower oil. The L-FABP induction was only found with long-chain fatty acids, with the nonmetabolizable, substituted fatty acid alpha-bromopalmitate being far more active. A hormonally mediated effect is unlikely because long-chain fatty acids induced L-FABP mRNA in the Caco-2 cell line cultured in serum-free medium. Therefore, long-chain fatty acids are strong inducers of L-FABP gene expression in the small intestine. In contrast to data found in the rat, I-FABP gene expression appears to be unaffected by a lipid-enriched diet in the mouse.
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