Search results for "NEUTROPHIL"
showing 10 items of 449 documents
Pharmacology of Ischemia-Reperfusion. Translational Research Considerations.
2016
Ischemia-reperfusion (IRI) is a complex physiopathological mechanism involving a large number of metabolic processes that can eventually lead to cell apoptosis and ultimately tissue necrosis. Treatment approaches intended to reduce or palliate the effects of IRI are varied, and are aimed basically at: inhibiting cell apoptosis and the complement system in the inflammatory process deriving from IRI, modulating calcium levels, maintaining mitochondrial membrane integrity, reducing the oxidative effects of IRI and levels of inflammatory cytokines, or minimizing the action of macrophages, neutrophils, and other cell types. This study involved an extensive, up-to-date review of the bibliography …
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.
Increased airway inflammatory cells in endurance athletes: what do they mean?
2003
Inflammatory cells are increased in the airways of endurance athletes, but their role in causing exercise-induced respiratory symptoms and bronchoconstriction, or their possible long-term consequences, are uncertain.To put the results of athlete studies in perspective, by analysing the pathogenesis of airway cell changes and their impact on respiratory function.Athletes of different endurance sports at rest showed increased airway neutrophils. Elite swimmers and skiers also showed large increases in airway eosinophils and lymphocytes, possibly related to chronic, exercise-related exposure to irritants or cold and dry air, respectively. Post-exercise studies reported variable responses of ai…
L-selectin regulates human neutrophil transendothelial migration
2021
ABSTRACT The migration of circulating neutrophils towards damaged or infected tissue is absolutely critical to the inflammatory response. L-selectin is a cell adhesion molecule abundantly expressed on circulating neutrophils. For over two decades, neutrophil L-selectin has been assigned the exclusive role of supporting tethering and rolling – the initial stages of the multi-step adhesion cascade. Here, we provide direct evidence for L-selectin contributing to neutrophil transendothelial migration (TEM). We show that L-selectin co-clusters with PECAM-1 – a well-characterised cell adhesion molecule involved in regulating neutrophil TEM. This co-clustering behaviour occurs specifically during …
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…
Generation and release of eosinophil chemotactic factor from human polymorphonuclear neutrophils by arachidonic acid
1978
This study describes the generation and release of an eosinophil chemotactic factor from human polymorphonuclear neutrophils, rat basophilic leukemia cells, and from a lymphocyte monocyte basophil suspension by arachidonic acid (AA). The eosinophil chemotactic factor (ECF) is highly specific for eosinophils and resembles the ECF activity obtained from human polymorpho-nuclear neutrophils after stimulation with the Ca ionophore or during phagocytosis. In this regard, AA-induced ECF represents a biological activity distinct from oxidized AA and its conversion products. AA may therefore have a dual function: it represents an important mechanism of cell activation; as AA is converted into prost…
Characterization of neutrophil subsets in healthy human pregnancies
2014
We have previously shown that in successful pregnancies increased arginase activity is a mechanism that contributes to the suppression of the maternal immune system. We identified the main type of arginase-expressing cells as a population of activated low-density granulocytes (LDGs) in peripheral blood mononuclear cells and in term placentae. In the present study, we analyzed the phenotype of LDGs and compared it to the phenotype of normal density granulocytes (NDGs) in maternal peripheral blood, placental biopsies and cord blood. Our data reveal that only LDGs but no NDGs could be detected in placental biopsies. Phenotypically, NDGs and LDGs from both maternal and cord blood expressed diff…
Phenylpropanoid and phenylisoprenoid metabolites from Asteraceae species as inhibitors of protein carbonylation.
2011
Abstract Three phenolic antioxidant and anti-inflammatory compounds: 7-methylaromadendrin, isoprenylhydroquinone glucoside, and 3.5-dicaffeoylquinic acid methyl ester, all isolated from Western Mediterranean Asteraceae species, have been studied for their inhibitory activity against protein carbonylation, a harmful post-translational modification of peptide chains associated with degenerative diseases. All compounds have proven to be effective, with 50% inhibitory concentration (IC 50 ) values in the micromolar range, against bovine serum albumin carbonylation caused by hypochlorite, peroxynitrite, and phorbol ester-induced leukocyte oxidative burst.
Antibacterial and antioxidant activities in Sideritis italica (Miller) Greuter et Burdet essential oils
2006
Sideritis italica (Miller) Greuter et Burdet is a widespread Lamiacea in the Mediterranean region used in traditional medicine. Essential oils were antibacterial against nine ATCC and as many clinically isolated Gram-positive and Gram-negative bacterial strains. Antibacterial activity was also found against Helicobacter pylori: a dose-dependant inhibition was shown between 5 and 25 microg/ml. The antibacterial activity of the oils was expressed as MICs (minimum inhibitory concentrations) and MBCs (minimum bactericidal concentrations). At a concentration between 3.9 and 250 microg/ml the oils showed a significant antibacterial effect against both Gram-negative and Gram-positive bacteria. In …
Mechanism of Reaction of Melatonin with Human Myeloperoxidase
2001
Recently, it was suggested that melatonin (N-acetyl-5-methoxytryptamine) is oxidized by activated neutrophils in a reaction most probably involving myeloperoxidase (Biochem. Biophys. Res. Commun. (2000) 279, 657-662). Myeloperoxidase (MPO) is the most abundant protein of neutrophils and is involved in killing invading pathogens. To clarify if melatonin is a substrate of MPO, we investigated the oxidation of melatonin by its redox intermediates compounds I and II using transient-state spectral and kinetic measurements at 25 degrees C. Spectral and kinetic analysis revealed that both compound I and compound II oxidize melatonin via one-electron processes. The second-order rate constant measur…