Two chemoattractants, the peptide N-formyl-met-leu-phe (FMLP), and the ether phospholipid, platelet activating factor (PAF), each stimulate a variety of in vitro responses in polymorphonuclear leucocytes (PMN). Because often more than one inflammatory mediator is active during inflammation, we determined the effect on PMN of sequential stimulation with these two agents. Before FMLP stimulation,...

It is presently believed that multiple mediators and interactions among mediators are involved in the pathogenesis of asthma. How then is an important mediator identified? In the case of platelet activating factor (PAF), the history goes back a long way. PAF is a family of structurally related ether-linked phospholipids that are formed as a result of the action of phospholipase A 2 and acetyltr...

The mechanism of tissue and cell injury in ischaemic bowel necrosis is unclear. The present study investigated the role of oxygen derived free radicals in the development of bowel necrosis using injections of platelet activating factor (PAF) into the mesenteric vasculature. Animals were pretreated with allopurinol or superoxide dismutase together with catalase, before administration of PAF. Sup...

Platelet-activating factor (PAF), a potent signaling lipid implicated as a mediator of pathological responses, has both negative chronotropic and inotropic effects on the heart, although the mechanism(s) involved is not well defined. Because activation of the muscarinic acetylcholine-activated K+ current (IK(ACh)) also produces a negative chronotropic and inotropic response in myocardium, this ...

Human plasma platelet-activating factor acetylhydrolase (PAF-AH) is a phospholipase A(2) that is primarily associated with low density lipoprotein (LDL). PAF-AH activity has also been found in high density lipoprotein (HDL), although it has recently been indicated that there is no PAF-AH protein in HDL. Plasma paraoxonase 1 (PON1) is an HDL-associated esterase, which also exhibits PAF-AH-like a...

Recent studies have implicated the lipid mediator platelet-activating factor (PAF) in UVB-mediated systemic immunosuppression known to be a major cause for skin cancers. Previously, our group has demonstrated that UVB irradiation triggers the production of PAF and oxidized glycerophosphocholines that act as PAF-receptor (PAF-R) agonists. The present studies explored the mechanisms by which UVB ...

Since its recognition as a substance released from rabbit basophils after IgE stimulation that is capable of causing platelet aggregation [ 1, 21, plateletactivating factor (PAF, l-alkyl-2-acetyl-sn-glycero-3phosphocholine) has continued to generate interest as a potent mediator of inflammation. Compared with other lipid mediators of inflammation, such as those generated from the cyclo-oxygenas...

Alkaline sphingomyelinase (alk-SMase) is a new member of the NPP (nucleotide pyrophosphatase/phosphodiesterase) family that hydrolyses SM (sphingomyelin) to generate ceramide in the intestinal tract. The enzyme may protect the intestinal mucosa from inflammation and tumorigenesis. PAF (platelet-activating factor) is a pro-inflammatory phospholipid involved in pathogenesis of inflammatory bowel ...

Platelet-activating factor (PAF [1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine]) is a phospholipid mediator released from activated macrophages, mast cells, and basophils that promotes pathophysiologic inflammation. Eosinophil responses to PAF are complex and incompletely elucidated. We show in this article that PAF and its 2-deacetylated metabolite (lysoPAF) promote degranulation (release of ...

Background Additional ablation strategies after pulmonary vein isolation (PVI) for patients with nonparoxysmal atrial fibrillation (non-PAF) lasting ≥2 years have not been fully effective. This is presumably because of insufficient identification non-PAF maintenance mechanisms. In this study, we employed a novel online and real-time phase mapping system, ExTRa Mapping, to identify modulate roto...