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The neutrophil NADPH-oxidase can be activated by protein kinase C (PKC) agonists such as phorbol myristate acetate (PMA), resulting in superoxide anion release. This superoxide release is independent of phosphatidylinositol 3-kinase (PI 3-kinase) because the inhibitor wortmannin does not affect the response. In this study, PMA is shown to also induce a(More)
Arachidonate and other unsaturated long-chain fatty acids were found to activate protein kinase C from human neutrophils. Kinase activation by arachidonate required calcium and was enhanced by diolein but did not require exogenous phosphatidylserine. Submaximal levels of arachidonate also enhanced the affinity of the kinase for calcium during activation by(More)
We investigated the capacity of bacterial endotoxin (lipopolysaccharide, LPS) to modify the oxidative metabolic response to membrane stimulation of human neutrophils. Neutrophils were pretreated for 60 min with LPS, 10 ng/ml, then stimulated by exposure to fixed immune complexes, the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (FMLP), or(More)
Mn2+ was shown to catalyze a nonenzymatic oxidation of NADPH in the presence of superoxide anion by means of an isotopic assay for measurement of the oxidation of NADPH to NADP+. Human polymorphonuclear leukocyte granule NADPH oxidase activity was evaluated in the absence of Mn2+ and was found to be higher in granules from phagocytizing cells than in(More)
We have compared the oxidative metabolism of human eosinophils (80%-90% purity) to that of neutrophils. Hexose monophosphate (HMP) shunt activity of eosinophils was higher than that of neutrophils under either resting or phagocytizing conditions. Eosinophil HMP shunt activity also was stimulated by phorbol myristate acetate, a membrane-active agent.(More)
F ~hagocytic cells contain a complicated enzyme system, termed NADPH oxidase, that is responsible for the production of toxic oxygen species (1). The enzyme transfers electrons from NADPH to 02, forming O2-, which then can dismutate into H202. Subsequently, other oxygen derivatives , such as hydroxyl radical and hypochlorous acid, may be formed.(More)
An isotopic assay for NADPH ixodase that measures the amount of NADP formed by the 6-phosphogluconate dehydrogenase reaction has been developed. Under appropriate conditions, the amount of NADP present is directly proportional to the amount of 14CO2 released from [1-14C]6-phosphogluconic acid. Because this assay employs radioisotopes, it is far more(More)
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