elongation of fatty acids while Sampath and Ntambi discuss the enzymes required for fatty acid desaturation. Finally, Rizzo discusses the key role of fatty aldehyde dehydrogenase and how mutations in this enzyme lead to defective barrier function and ichthyosis. Second, the utilization of fatty acids in the synthesis of phospholipids and triglycerides and the catabolism of these compounds is di...

Endothelial barrier function is altered by the release of soluble polymorphonuclear leukocyte (PMN)-derived mediators during inflammatory states. However, endogenous pathways to describe such changes are only recently appreciated. Using an in vitro endothelial paracellular permeability model, cell-free supernatants from formylmethionylleucylphenylalanine-stimulated PMNs were observed to signifi...

BACKGROUND Elevated H2O2 levels are associated with inflammatory diseases and H2O2 exposure is known to disrupt epithelial barrier function, leading to increased permeability and decreased electrical resistance. In normal human bronchial epithelial (NHBE) cells, fully differentiated at the air liquid interface (ALI), H2O2 activates an autocrine prostaglandin pathway that stimulates transmembran...

The pathogenesis of inflammatory bowel disease (IBD) is multifactorial with data suggesting the role of a disturbed interaction between the gut and the intestinal microbiota. A defective mucosal barrier may result in increased intestinal permeability which promotes the exposition to luminal content and triggers an immunological response that promotes intestinal inflammation. IBD patients displa...

Cytosolic Ca2+ concentration ([Ca2+]i) plays an important role in control of pulmonary vascular endothelial cell (ECs) barrier function. In this study, we investigated whether thapsigargin- and ionomycin-induced changes in cytosolic Ca2+ induce permeability in rat pulmonary microvascular (RPMV) versus macrovascular (RPA) ECs. In Transwell cultures, RPMVECs formed a tighter, more restrictive bar...

Although most cell membranes permit rapid flux of water, small nonelectrolytes, and ammonia, the apical membranes of bladder epithelial umbrella cells, which form the bladder permeability barrier, exhibit strikingly low permeabilities to these substances. In cystitis, disruption of the bladder permeability barrier may irritate the bladder wall layers underlying the epithelium, causing or exacer...

PURPOSE The purpose of this study was to evaluate the permeability of the blood-brain barrier after sonication by pulsed high-intensity focused ultrasound and to determine if such an approach increases the tumor:ipsilateral brain permeability ratio. MATERIALS AND METHODS F98 glioma-bearing Fischer 344 rats were injected intravenously with Evans blue with or without blood-tumor barrier disrupt...

The permeabilities of the blood-retinal (BRB) and blood-brain (BBB) barriers to sucrose were determined simultaneously using an intravenous injection technique in the rat. The method involved direct sampling of retinal tissue in order to avoid errors caused by sucrose penetration across other components of the blood-ocular barrier. The permeability X surface area (PS) product for the BRB was ap...

Strategies to improve pulmonary endothelial barrier function are needed to reverse the devastating effects of vascular leak in acute respiratory distress syndrome. FTY720 is a pharmaceutical analogue of the potent barrier-enhancing phospholipid sphingosine 1-phosphate (S1P). FTY720 decreases vascular permeability by an incompletely characterised mechanism that differs from S1P. Here, we describ...