This study was designed to examine further the role of platelet-activating factor ( @entity5567 ) in @entity565 , comparing leukotriene B4 (LTB4) release, @entity1437 activity and intracellular @entity460 levels ([ @entity141 ]i) in macrophages. LTB4 and other lipoxygenase metabolites in macrophages in bronchoalveolar lavage fluids obtained from 23 @entity748 @entity1 and 20 control subjects were measured by reverse-phase high-performance liquid chromatography. [ @entity141 ]i was monitored using the fluorescent probe @entity593 . The basal LTB4 release of resting macrophages was not different between groups (0.02+/-0.01 versus 0.05+/-0.02 ng x 10(-6) cells). When stimulated with @entity460 ionophore @entity3365 (2.5 microM), however, macrophages from @entity748 @entity1 released more LTB4 than cells from control subjects (30.2+/-3.4 versus 13.7+/-2.1 ng x 10(-6) cells). Although @entity5567 alone did not alter LTB4 release, it enhanced the response to subsequent @entity3365 stimulation. This effect was noted following short treatment (i.e., 5 min) at concentrations of > or =1.0 microM @entity5567 , with the maximal effect noted after treatment with 5.0 microM @entity5567 + 2.5 microM @entity3365 (105.1+/-6.7 versus 15.3+/-2.6 ng x 10(-6) cells). Treatment of macrophages with @entity5567 also increased @entity1437 activity and [ @entity141 ]i more in cytosols from @entity748 @entity1 than in cytosols from control subjects. These findings support a role of intracellular @entity460 in the activation of @entity1437 which, in turn, augments the release of @entity8285 . Because levels of platelet-activating factor may be increased in the lung during @entity565 and can increase the subsequent release of a chemotactic mediator leukotriene B4, from macrophages, these findings suggest that platelet-activating factor may prime the constitutive cells of the lung to augment inflammatory effects important in the pathogenesis of @entity565 .

Platelet-activating factor increases leukotriene B4 release in stimulated alveolar macrophages from XXXX @entity1 .

@entity748 :: ('MESH:D013224', 'Disease') :: ['asthmatic'] @entity1437 :: ('240', 'Gene') :: ['5-lipoxygenase'] @entity1 :: ('9606', 'Species') :: ['patients'] @entity8285 :: ('MESH:D007975', 'Chemical') :: ['leukotriene B4'] @entity565 :: ('MESH:D001249', 'Disease') :: ['asthma'] @entity593 :: ('MESH:D016257', 'Chemical') :: ['fura-2'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium'] @entity3365 :: ('MESH:D000001', 'Chemical') :: ['A23187'] @entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca2+'] @entity5567 :: ('CHEBI:52450', 'Chemical') :: ['PAF']
@entity748 :: (MESH:D013224,Disease) :: ['asthmatic']
