Polymorphonuclear leucocytic neutrophils

The neutrophils (also called polymorphonuclear leucocytes, PMNs), which are the professional phagocytes of the body. They constitute >70% of the total leucocyte population, remaining in the circulatory system for less than 48 hours before migrating into the tissues, in response to a suitable stimulus, where they phagocytose material. They possess receptors forFc and activated C3 which enhance their phagocytic ability (see later in chapter). 

Polymorphonuclear leucocytes (PMNs) employ a system comprising myeloperoxidase, hydrogen peroxide, and a halide factor to kill microorganisms and tumour cells. This process is sometimes loosely called the respiratory burst , which refers to the sudden rise in oxygen consumption by the phagocytosing neutrophils that is independent of the mitochondrial electron transport chain. 

In polymorphonuclear leucocytes (PMNL, neutrophils), secretory responses measured as vitamin B -binding protein release were inhibited by feverfew extract when the response was induced by the chemotactic peptide FMLP or arachidonic acid but not when the calcium ionophore A23187 was... 

Levamlsole and Related Compounds - Recent progress in the immunopharmaco-logical and clinical characterization of the immunoregulatory anthelmintic levamisole (59) has been reviewed.Levamisole has been shown to restore compromised responses of polymorphonuclear leucocytes, monocytes, macrophages, and T lymphocytes in a variety of systems both in vitro and, more importantly, in vivo. Thus, monocyte and neutrophil motility and chemo-... 

Leung BP, Culshaw S, Grade JA, Hunter D, Canetti CA, Campbell C, Cunha F, Liew FY, Mclnnes IB A role for IL-18 in neutrophil activation. J Immunol 2001 167 2879-2886. Cassatella MA, Guasparri I, Ceska M, Bazzoni F, Rossi F Interferon-gamma inhibits interleukin-8 production by human polymorphonuclear leucocytes. Immunology 1993 78 177-184. 

Thelen, M. and Didichenko, S.A. (1997). G-protein-coupled receptor-mediated activation of PI-3-kinase in neutrophils. Ann. New York Acad. Sci. 832, 368-382. Thompson, H.L., Shiroo, M. and SaHatvala, J. (1993). The chemotachc factor N-formylmethionyl-leucyl-phenylalanine activates microtubule-associated protein 2 (MAP) kinase and MAP kinase kinase in polymorphonuclear leucocytes. Biochem. J. 290, 483-488. 

Nalbandian (1982) and Nalbandian et al. (1983) modified the nitroblue tetrazohum immuno-bead test (O Donnell et al. 1979, Jabs et al. 1980) to detect cases in which faihng and absent phagocytic activity and respiratory burst intensity in ah-quots of polymorphonuclear leucocytes have been functionally restored to normal by in vitro piracetam treatment of such neutrophils. 

There was no evidence from cell-free assay systems that carvedilol is a scavenger for 02 or NO (Asbrink et al. 2000). Carvedilol did not affect other reactions dependent on NO, e.g. spontaneous of formyl-methionyl-leucyl-phenylalanine-stimulated polymorphonuclear leucocyte migration or hpoxin A4-, fMLP-, or A23187-induced neutrophil cytotoxicity for human umbiUcal vein endothehal cells. Thus, these effects point to the possibility that carvedilol modulates the NADPH oxidase of polymorphonuclear leucocytes but leaves the nitric oxide synthase of phagocytes intact. Carvedilol exerted poor reactivity toward phenoxyl, alkoxyl, and per-oxyl radicals in acetonitrile solution nor did it show an appreciable antioxidant effect against either the peroxyl radical-induced oxidation of methyl Unole-... 

Neutrophil apoptosis may be important in regulating the inflammatory process by controlling neutrophil numbers and thus activity. Exogenous inhaled nitric oxide is now a widely used therapy in patients with acute lung injury, and its effects on apoptosis may be important. In a model of nitric oxide-treated lung injury, Blaylock et al. (1998) incubated polymorphonuclear leucocytes isolated fi om venous blood for up to 16 h with and without 1.7 ng/ml lipopolysaccharide and the nitric oxide donor GEA-3162 or the peroxynitrite donor SIN-1. Apoptosis was attenuated when cells were exposed to lipopolysaccharide and both nitric oxide and peroxynitrite dose-dependently inhibited this suppression at all time points and was most apparent at 16 h (P = 0.004 and 0.001, respectively). 

It is still unclear whether neutrophil binding to the endothelial cell surface affects VE-cadherin functions (Vestweber 2000). It was proposed that adhesion of polymorphonuclear leucocytes to human umbilical endothelial cells leads to the disorganisation of the VE-cadherin-dependent endothe-... 

Ual adherens junctions. Combined immunofluorescence and biochemical data suggested that following adhesion of polymorphonuclear leucocytes to the endothelial cell surface, P-catenin as well as pla-koglobin was lost from the cadherin/catenin complex and from total cell lysates (Del Maschio et al. 1996, Allport etal. 1997). However, Moll etal. (1998) demonstrated that the adhesion-dependent disappearance of endotheUal catenins in these experiments was not mediated by a leucocyte to en-dotheUum signalhng event, but was due to the activity of a neutrophil protease which had been experimentally released upon lysis and handUng of the co-incubated neutrophils and endotheUal ceUs. 

Crude extracts inhibit both human blood platelet aggregation and secretory activity in platelets and neutrophils (polymorphonuclear leucocytes). In vitro, extracts protect endothelial cell wall of rabbit aortas from perfusion-induced injury and inhibit deposition of human platelets on collagen. ... 

PMN polymorphonuclear granulocyte any of several types of leucocyte characterized as having granular cytoplasms and lobed nuclei, including eosinophils, basophils, mast cells and neutrophils. 

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