Search results for "Leukotriene"
showing 10 items of 103 documents
Effect of bakuchiol on leukocyte functions and some inflammatory responses in mice.
1996
Abstract The effects of bakuchiol, a meroterpenoid isolated from the leaves of Psoralea glandulosa L., on phospholipase A2 (PLA2) activity from different sources, human neutrophil responses, zymosan air pouch and topical inflammation in mice, were investigated. This natural product was a weak inhibitor of secretory and intracellular PLA2 but dose-dependently reduced the formation of LTB4 and TXB2 by human neutrophils and platelet microsomes, respectively. In addition, bakuchiol inhibited degranulation in human neutrophils, whereas superoxide generation was not affected. In mice, bakuchiol decreased cell migration, myeloperoxidase activity and eicosanoid levels in the air pouch inflammation …
Mediator-Induced Changes in Macromolecular Permeability in the Rat Mesenteric Microcirculation
1995
An intravital fluorescence microscopic method for measurement of changes in macromolecular permeability has been established in the mesenterial microcirculation of the rat. After exteriorization of the fat-free distal part of the ileal mesentery, a 1-hr period of stabilization was followed by the injection of FITC-labeled macromolecules. Five minutes later, histamine, leukotriene B4, or leukotriene C4 was topically applied to the tissue by means of a micromanipulator. Areas of 1 mm2 were videotaped with a SIT camera. The fluorescence intensity of these areas was measured by an analogous video image processing system and displayed as gray value histograms. The shift of the frequency of gray …
Suppression of leukotriene B4 and tumour necrosis factor alpha release in acute inflammatory responses by novel prenylated hydroquinone derivatives.
1998
A series of prenyl hydroquinone derivatives synthesized as structural analogs of marine products were tested for their effects on inflammatory responses in vitro and in vivo. 2-Prenyl-1,4-hydroquinone (H1), 2-diprenyl-1,4-hydroquinone (H2), 2-triprenyl-1,4-hydroquinone (H3) and 2-tetraprenyl-1,4-hydroquinone (H4) scavenged reactive oxygen species and inhibited 5-lipoxygenase (5-LO) activity in human neutrophils. The inhibition of 5-LO activity was demonstrated in vivo in the mouse air pouch injected with zymosan and arachidonic acid-induced ear inflammation. The four compounds suppressed the production of tumour necrosis factor alpha (TNFalpha) in J774 cells stimulated with lipopolysacchari…
Inhibition of phospholipase A2 activities and some inflammatory responses by the marine product ircinin
1996
The marine product ircinin has been tested for its effects on secretory and cytosolic phospholipase A2 (PLA2) activities in vitro as well as for inhibition of cellular functions in human neutrophils and inflammatory responses in mice. Ircinin inhibited Naja naja venom, human synovial recombinant, bee venom and zymosan-injected rat air pouch PLA2 with IC50 values in the microM range, similar to those of the known inhibitor scalaradial. On the other hand, ircinin was less active on cytosolic PLA2 from human monocytes and decreased potently the release of LTB4 in human neutrophils. This marine product affected weakly human neutrophil functions like superoxide generation and degranulation. In t…
Lipoxygenase-derived arachidonic acid metabolites in chronic obstructive pulmonary disease
2011
Background and Objective. Chronic obstructive pulmonary disease (COPD) is characterized by a persistence of inflammation in large and small airways. We hypothesized that this could be caused by the inability of an inflammatory process to resolve. In the resolution of inflammation, a switching of arachidonic acid metabolism from the production of proinflammatory leukotriene B4 (LtB4) to the synthesis of anti-inflammatory lipoxins plays an important role. The aim of our study was to determine the content of lipoxin A4 (LXA4) and LtB4 in induced sputum of patients with exacerbated COPD and to compare it to healthy controls, as well as to analyze the relationship between proinflammatory and ant…
Muscarinic receptors, leukotriene B4 production and neutrophilic inflammation in COPD patients.
2005
Background: Acetylcholine (ACh) plays an important role in smooth muscle contraction and in the development of airway narrowing; preliminary evidences led us to hypothesize that ACh might also play a role in the development of airways inflammation in chronic obstructive pulmonary disease (COPD). Methods: We evaluated the concentrations of leukotriene B4 (LTB4) in induced sputum, and the expression of Ach M1, M2, and M3 receptors in sputum cells (SC) obtained from 16 patients with COPD, 11 smokers, and 14 control subjects. The SC were also treated with ACh and the production of LTB4 assessed in the presence or absence of a muscarinic antagonist (oxitropium). In blood monocytes, we evaluate…
Effect of walnut-enriched meat on the relationship between VCAM, ICAM, and LTB4 levels and PON-1 activity in ApoA4 360 and PON-1 allele carriers at i…
2011
Cardiovascular risk depends largely on paraoxonase (PON-1) and apolipoprotein A4 (APOA4) gene polymorphisms. To compare the effects of consumption of walnut-enriched meat versus low-fat meat (LM) on selected soluble adhesion molecules and leukotrienes (LTB4). In all 22 subjects at increased cardiovascular risk were taken. It is a non-blinded, cross-over, placebo-controlled study. Two 5-week experimental periods separated by 4–6 week wash-out interval. Participants consumed walnut-enriched meat during one period and LM during the other. Diet characteristics, HDLc, Apo A1, paraoxonase, sVCAM-1, sICAM-1 and LTB4 were analysed. PON-1 55, PON-1 192 and APOA4 360 polymorphism effects were also as…
Involvement of secretory phospholipase A2 activity in the zymosan rat air pouch model of inflammation.
1996
1. In the zymosan rat air pouch model of inflammation we have assessed the time dependence of phospholipase A2 (PLA2) accumulation in the inflammatory exudates as well as cell migration, myeloperoxidase activity, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. 2. A significant increase in PLA2 activity was detected in 1,200 g supernatants of exudates 8 h after injection of zymosan into rat air pouch. This event coincided with peaks in cell accumulation (mainly neutrophils) and myeloperoxidase activity in exudates and was preceded by a rise in eicosanoid levels. 3. This enzyme (without further purification) behaved as a secretory type II PLA2 with an optimum pH at 7-8 units, lack o…
Inhibition of human sPLA2 and 5-lipoxygenase activities by two neo-clerodane diterpenoids
1999
Abstract The inhibitory effect of two neo -clerodane diterpenoids, E -isolinaridial (EI) and its methylketone derivative (EIM), isolated from Linaria saxatilis var. glutinosa , on PLA2 and other enzyme activities involved in the inflammatory process was studied. Both compounds inhibited human synovial sPLA 2 in a concentration-dependent manner with IC 50 values of 0.20 and 0.49 μM, respectively, similar to scalaradial. Besides, these compounds decreased the cell-free 5-lipoxygenase activity and A23187-induced neutrophil LTB 4 biosynthesis. Another function of human neutrophils, such as receptor-mediated degranulation, was also significantly reduced. In contrast, none of the compounds affect…
Screening of some rare endemic Italian plants for inhibitory activity on 5-lipoxygenase
2003
Abstract The extracts of four rare plants found on the islands of Sicily, Vulcano and Marettimo, Southern Italy, were screened for their inhibitory effect on the production of leukotriene B 4 by 5-lipoxygenase in intact cells. The methanol extracts of pods of Cytisus aeolicus and aerial parts of Thymus richardii were the most active extracts, inhibiting almost completely the leukotriene B 4 production at 200 and 50 μg/ml, respectively.