Lipoxin
Mostrando 13-24 de 28 artigos, teses e dissertações.
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13. On the stereochemistry and biosynthesis of lipoxin B.
Lipoxin B (LXB) was prepared by incubation of (15S)-15-hydroperoxy-5,8,11-cis-13-trans-icosatetraenoic acid (15-HPETE) with human leukocytes. Comparison with a number of trihydroxyicosatetraenes prepared by total synthesis showed that biologically derived LXB is (5S,14R,15S)-5,14,15-trihydroxy-6,10,12-trans-8-cis-icosatetraenoi c acid. Two isomers of LXB wer
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14. Lipoxins: novel series of biologically active compounds formed from arachidonic acid in human leukocytes.
Trihydroxytetraenes, a novel series of oxygenated derivatives formed from arachidonic acid in human leukocytes, were recently isolated [Serhan, C. N., Hamberg, M. & Samuelsson, B. (1984) Biochem. Biophys. Res. Commun. 118, 943-949]. The structure of the major compound was established--i.e., 5,6,15L-trihydroxy-7,9,11,13-icosatetraenoic acid. The present study
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15. Pathogen-induced chemokine secretion from model intestinal epithelium is inhibited by lipoxin A4 analogs.
Enteric pathogens induce intestinal epithelium to secrete chemokines that direct movement of polymorphonuclear leukocytes. Mechanisms that might downregulate secretion of these proinflammatory chemokines and thus contain intestinal inflammation have not yet been elucidated. The antiinflammatory activities exhibited by the arachidonate metabolite lipoxin A4 (
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16. Interaction of a selective cyclooxygenase-2 inhibitor with aspirin and NO-releasing aspirin in the human gastric mucosa
In addition to inhibiting cyclooxygenase (COX)-1-derived prostanoid biosynthesis, aspirin acetylates COX-2, enabling the conversion of arachidonic acid to 15(R)-epi lipoxin A4, or aspirin-triggered lipoxin (ATL). Selective COX-2 inhibitors block ATL formation and exacerbate mucosal injury in rats treated with aspirin. In the present study, we have examined w
National Academy of Sciences.
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17. Lipoxin A4 modulates transmigration of human neutrophils across intestinal epithelial monolayers.
Neutrophil (PMN) migration across intestinal epithelial barriers, such as occurs in many disease states, results in modifications in epithelial barrier. Here, we investigated the impact of lipoxin A4 (LXA4), an eicosanoid with counterregulatory inflammatory roles, on PMN migration across cultured monolayers of the human intestinal epithelial cell line T84. T
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18. Selective incorporation of (15S)-hydroxyeicosatetraenoic acid in phosphatidylinositol of human neutrophils: agonist-induced deacylation and transformation of stored hydroxyeicosanoids.
The uptake and mobilization of (15S)-hydroxy-5,8,11-cis-13-trans-eicosatetraenoic acid (15-HETE), a major product of arachidonic acid metabolism, was examined with human neutrophils (polymorphonuclear leukocytes; PMNs). Upon exposure to labeled 15-HETE, PMNs rapidly (15 sec to 20 min) incorporated approximately 20% of the label into phosphatidylinositol, whi
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19. Proinflammatory Activity of a Cecropin-Like Antibacterial Peptide from Helicobacter pylori
Helicobacter pylori, the bacterial pathogen associated with gastritis and peptic ulcers, is highly successful in establishing infection in the human gastric mucosa, a process typically associated with massive infiltration of inflammatory cells. Colonization of the mucosa is suggested to be facilitated by H. pylori-produced cecropin-like peptides with antibac
American Society for Microbiology.
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20. Lipoxin A4 antagonizes cellular and in vivo actions of leukotriene D4 in rat glomerular mesangial cells: evidence for competition at a common receptor.
Lipoxin A4 (LXA4) was competitive with [3H]leukotriene D4 (LTD4) for specific binding to cultured rat glomerular mesangial cells. Half-maximal inhibition was obtained with 100 nM LXA4, compared with 10 nM for unlabeled LTD4. At 10 and 50 nM LXA4 induced low, but significant, increases in mesangial-cell inositol trisphosphate generation: 48% and 44% increases
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21. On the nature of the 5-lipoxygenase reaction in human leukocytes: enzyme purification and requirement for multiple stimulatory factors.
Arachidonate 5-lipoxygenase was purified 400-fold from homogenates of human peripheral blood leukocytes by a combination of ammonium sulfate fractionation, gel filtration chromatography, and HPLC on anion exchange and hydroxylapatite columns. NaDodSO4/polyacrylamide gel electrophoresis of the purified protein revealed the presence of a single major band (app
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22. Leukotriene B4 receptor transgenic mice reveal novel protective roles for lipoxins and aspirin-triggered lipoxins in reperfusion
Polymorphonuclear neutrophil (PMN) activation is pivotal in acute inflammation and injury from reperfusion. To elucidate components controlling PMNs in vivo, we prepared novel transgenic mice with the human leukotriene (LT) B4 receptor (BLTR) for functional characterization. Overexpression of BLTR in leukocytes dramatically increased PMN trafficking to skin
American Society for Clinical Investigation.
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23. On the nature of the 5-lipoxygenase reaction in human leukocytes: characterization of a membrane-associated stimulatory factor.
When 10,000 X g supernatants of human leukocyte homogenates were subjected to centrifugation at 100,000 X g for 75 min, the activity of 5-lipoxygenase decreased by 30-60%, even though no enzyme was detectable in the resuspended 100,000 X g pellet. Recombination of the 100,000 X g supernatant and pellet resulted in a restoration of the lost enzymatic activity
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24. A β-oxidation-resistant lipoxin A4 analog treats hapten-induced colitis by attenuating inflammation and immune dysfunction
Lipoxins and aspirin-triggered 15-epi-lipoxins (ATL) are counter-regulatory eicosanoids with potent antiinflammatory actions. Oral efficacy and mechanism of action of ZK-192, a β-oxidation-resistant 3-oxa-ATL analog, were examined in trinitrobenzenesulphonate (TNBS)-induced colitis. When dosed orally once daily, 300 and 1,000 μg/kg ZK-192 markedly attenuat
National Academy of Sciences.