Search results for "Zymosan"
showing 10 items of 58 documents
Seminal plasma-induced suppression of the respiratory burst of polymorphonuclear leukocytes and monocytes.
1984
Summary: Based on recent findings indicating suppression of lymphocytic functions by seminal plasma (SP) we tested the effects of SP from men with normo- and oligozoospermia (n = 7, each) on the generation of luminol-enhanced chemiluminescence (CL) of polymorphonuclear leukocytes (PMN) and monocytes (Mo) stimulated in vitro with zymosan. We found a complete suppression of CL of PMN and Mo by undiluted SP's, 1,000-fold dilutions still induced ≥ 20 percent inhibition. There was no difference between normo- and oligozoospermic men in inhibition of CL both with PMN and Mo. Protein concentrations of SP's were closely the same; all SP were free of the complement components C4 and C3c. After dialy…
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…
Toll-like receptor 2 mediates prostaglandin E2 production in murine peritoneal macrophages and splenocytes in response to Candida albicans
2004
The involvement of Toll-like receptor 2 (TLR2) and TLR4 in triggering signal transduction pathways leading to prostaglandin E(2) (PGE(2)) production in response to Candida albicans has been studied in cells from wild-type, TLR2-/- and TLR4-/- knockout mice. In vitro PGE(2) production by macrophages challenged with zymosan, yeast or hypha cells was strongly inhibited in TLR2-deficient cells, but not in TLR4-/- cells, as compared to macrophages from wild-type mice. PGE(2) production was dependent on de novo cyclooxygenase-2 (Cox2) synthesis, since unchallenged cells failed to produce PGE(2) and specific Cox2 inhibition during challenge totally blocked PGE(2) production. Similar results were o…
Cycloamphilectenes, a new type of potent marine diterpenes: inhibition of nitric oxide production in murine macrophages.
2003
The inhibitory effect of a series of 6 cycloamphilectenes, novel marine diterpenes based on amphilectene skeletons and isolated from the Vanuatu sponge Axinella sp., on NO, PGE(2) and TNFalpha production in murine peritoneal macrophages was studied. These compounds reduced potently nitric oxide production in a concentration-dependent manner with IC(50) values in the submicromolar range (0.1-4.3 microM). Studies on intact cells and Western blot analysis showed that the more potent cycloamphilectenes reduced the expression of inducible nitric oxide synthase without affecting cyclo-oxygenase-2 expression. Among them cycloamphilectene 2, the unique compound bearing an exocyclic methylene group,…
Phospholipase A2 and arachidonic acid: a common link in the generation of the eosinophil chemotactic factor (ECF) from human PMN by various stimuli.
1980
An eosinophil chemotactic factor (ECF) of low molecular weight can be generated and released from human polymorphonuclear neutrophils by the calcium ionophore, phagocytosis of zymosan particles, arachidonic acid, and phospholipase A2. Since the activation of cells by the ionophore and during the phagocytic event leads to phospholipid turnover, with the subsequent generation of arachidonic acid, it is reasonable that phospholipase A2 represents the common link for ECF production. The kinetics of ECF release by phospholipase A2 is similar to the pattern observed with the various stimuli. After a rapid rise in activity a decline occurred at later times of secretion, suggesting a mechanism of i…
Inhibition of 5-lipoxygenase activity by the natural anti-inflammatory compound aethiopinone
2001
Objetive and Design: We have investigated the mechanisms of action of aethiopinone, an anti-inflammatory compound from Salvia aethiopis L. roots.¶Material and Subjects: Human neutrophils from healthy volunteers and murine peritoneal macrophages. Swiss mice were randomly divided into groups of six animals.¶Treatment: Test compounds were applied topically in the mouse ear oedema test. In the air pouch, mice received aethiopinone (0.001-0.5 μmol/pouch or 12.5-50 mg/kg p.o.).¶Methods: LTB4 production was assayed in human neutrophils and COX-2 and iNOS activities in murine macrophages. Air pouches were induced subcutaneously in mice and injected with zymosan on the day six. Mouse ear oedema was …
Dysidotronic acid, a new sesquiterpenoid, inhibits cytokine production and the expression of nitric oxide synthase.
2001
In a previous study, we reported a new bioactive sesquiterpenoid, named dysidotronic acid, to be a potent, selective human synovial phospholipase A(2) inhibitor. Dysidotronic acid is a novel, non-complex manoalide analogue lacking the pyranofuranone ring. We now investigate the effect of this compound on cytokine, nitric oxide and prostanoid generation on the mouse macrophage cell line RAW 264.7, where it showed a dose-dependent inhibition with inhibitory concentration 50% values in the micromolar range. This effect was also confirmed in the mouse air pouch injected with zymosan. Dysidotronic acid inhibited the production of tumor necrosis factor alpha and interleukin-1 beta as well as the …
Crystal-phagocyte interaction in calcinosis interstitialis.
1984
Based on recent findings indicating the stimulation of the respiratory burst in human neutrophils by crystal phagocytosis, ectopic calcified nodules of a patient with calcinosis interstitialis were exposed to autologous granulocytes and monocytes in vitro. The activity of the respiratory burst was determined by luminol-enhanced chemiluminescence. Controls included amorphous monosodium urate, microcrystalline monosodium urate, hydroxyapatite, and zymosan. Microcrystalline monosodium urate elicited a marked stimulation of both granulocytes and monocytes as did hydroxyapatite in granulocytes. Hydroxyapatite caused no stimulation of monocytes, possibly reflecting selective functional modulation…
Modulation of haem oxygenase-1 expression by nitric oxide and leukotrienes in zymosan-activated macrophages
2001
Phagocytosis of unopsonized zymosan by RAW 264.7 macrophages upregulated protein expression of haem oxygenase-1 (HO-1), inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) in a time- and concentration-dependent manner. In the presence of zymosan, exogenous prostaglandin E(2) (PGE(2)) did not exert significant effects on the expression of these three enzymes. In contrast, exogenous leukotriene B(4) (LTB(4)) and LTC(4) in the nanomolar range inhibited HO-1 and iNOS expression, as well as nitrite accumulation. The COX inhibitors indomethacin and NS398 weakly inhibited HO-1 expression but had no effect on iNOS and COX-2 expression or nitrite. In contrast, the 5-lipoxygenase (5-…
Prostaglandin production by human polymorphnuclear leucocytes during phagocytosis in vitro.
1977
Human polymorphonuclear leukocytes were found to be able to synthetize and release substantial amounts of PGE2' when stimulated by a phagocytic stimulus such as zymosan particles coated with complement. Hydrocortisone, at a concentration of 10(-5) M, which proved to be effective in other biological systems, failed to inhibit phagocytosis and PG release.