PURPOSE The aims of the study were to characterize the signal transduction responses to platelet-activating factor (PAF) and to monitor the downstream effects of PAF on the production of proinflammatory cytokines in human conjunctival epithelial cells (HCECs). METHODS The generation of inositol phosphates ([(3)H]IPs) from [(3)H]phosphoinositide (PI) hydrolysis and the mobilization of intracel...

BACKGROUND Detection of paroxysmal atrial fibrillation (PAF) in acute ischemic stroke patients poses diagnostic challenge. The aim of this study was to predict the presence of PAF by means of 12-lead ECG in patients with acute ischemic stroke. Our hypothesis was that P-wave dispersion (P(d)) might be a useful marker in predicting PAF in patients with acute ischemic stroke. METHODS 12-lead res...

Metabolism of platelet-activating factor (PAF) in rabbit plasma or in rabbit platelets was studied. [C3H3]-Labeled PAF was degraded into lysoPAF and choline in plasma. An agonist of PAF, NT071 was not degraded in the plasma. Albumin protects the degradation of PAF in plasma deprived of albumin but not the degradation of lysoPAF. These findings indicate that PAF may be metabolized in plasma by a...

BACKGROUND Platelet-activating factor (PAF) is a highly potent phospholipid mediator responsible for the life-threatening manifestations of anaphylaxis. PAF acetylhydrolase (PAF-AH) inactivates PAF and protects against severe anaphylaxis whereas deficiency of PAF-AH predisposes to severe or fatal anaphylaxis. Determinants of PAF-AH activity have not been studied in patients with peanut allergy....

Platelet-activating factor (PAF), an inflammatory phospholipid, induces ventricular arrhythmia via an unknown ionic mechanism. We can now link PAF-mediated cardiac electrophysiological effects to inhibition of a two-pore domain K(+) channel [TWIK-related acid-sensitive K(+) background channel (TASK-1)]. Superfusion of carbamyl-PAF (C-PAF), a stable analog of PAF, over murine ventricular myocyte...

BACKGROUND Platelet activating factor (PAF) is a potent mediator of inflammation. Inhalation of PAF causes acute bronchoconstriction and a transient fall in white blood cell count in humans. Salmeterol inhibits pulmonary inflammation induced by PAF in guinea pigs. METHODS The effect of salmeterol on effects induced by PAF was investigated in eight normal subjects who inhaled salmeterol (50 mi...

Platelet-activating factor (PAF), a phospholipid second messenger, has diverse physiological functions, including responses in differentiated endothelial cells to external stimuli. We used human umbilical vein endothelial cells (HUVECs) as a model system. We show that PAF activated pertussis toxin-insensitive G q protein upon binding to its seven transmembrane receptor. Elevated cAMP levels wer...

Platelet activating factor (PAF) interacts with cell surface G protein-coupled receptors on leukocytes to induce degranulation, leukotriene C(4) (LTC(4)) generation, and chemokine CCL2 production. Using a basophilic leukemia RBL-2H3 cell line expressing wild-type PAF receptor (PAFR) and a phosphorylation-deficient mutant (mPAFR), we have previously demonstrated that receptor phosphorylation med...

Although well-characterized in the lung, the role of platelet-activating factor (PAF) in inflammation in the central nervous system is undefined. Using rabbit models of meningitis and pneumonia, PAF was found to induce significant blood-brain barrier permeability and brain edema at doses five times lower than those required to generate leukocyte recruitment to the subarachnoid space. Both leuko...

The innate immune system is the first line of host defense against invading organisms. Thus, pathogens have developed virulence mechanisms to evade the innate immune system. Here, we report a novel means for inhibition of neutrophil recruitment by Group A Streptococcus (GAS). Deletion of the secreted esterase gene (designated sse) in M1T1 GAS strains with (MGAS5005) and without (MGAS2221) a nul...