Hydroxyl radical as a potential intracellular mediator of polymorphonuclear neutrophil apoptosis.

We investigated reactive oxygen species (ROS) involvement in polymorphonuclear neutrophilic leukocyte (neutrophil) apoptosis triggering. Neutrophils were incubated with xanthine oxidase (XO), which produces superoxide anion (O2.-) and hydrogen peroxide (H2O2) or glucose oxidase (GO), which produces only H2O2.

Inhibition of human neutrophil binding to hydrogen peroxide-treated endothelial cells by cAMP and hydroxyl radical scavengers.

Hydrogen peroxide (H2O2) increases adherence of human polymorphonuclear neutrophils (PMN) to cultured human umbilical vein endothelial cells (HUVEC). Catalase and HO. scavengers did not affect the increased PMN adherence to HUVEC stimulated by other compounds such as phorbol myristate acetate (PMA) and thrombin, showing that the observed effect was H2O2- and HO.

Activities of lung NADPH-cytochrome C-reductase and of cytochrome P-450 peroxidase during the protection of rat from hyperoxic injury by polyriboinosinic acid-polyribocytidilic acid.

Rats exposed to normobaric oxygen received a single i.p. injection of 2.

A comparison of the priming effect of phorbol myristate acetate and phorbol dibutyrate on fMet-Leu-Phe-induced oxidative burst in human neutrophils.

Phorbol esters such as phorbol myristate acetate (PMA) and phorbol dibutyrate (PDBU) are generally considered to have similar effects through a similar mechanism, i.e. protein kinase C (PKC) activation.

Dual effect of phorbol myristate acetate on chemoattractant-induced locomotion of human neutrophils.

Phorbol myristate acetate (PMA) is a potent activator of Ca2+/phospholipid-dependent protein kinase (PKC) and was used to study the involvement of this kinase in human polymorphonuclear neutrophil (PMN) locomotion. Preincubation of PMNs with low concentrations of PMA (4 to 64 x 10(-11) M) had the following effects: (1) fMet-Leu-Phe-induced migration under agarose was increased when the chemoattractant was used at the suboptimal concentration of 10(-8)M and not at the optimal concentration of 10(-7)M; (2) no effect on spontaneous or serum- or LTB4- induced migration at either suboptimal or optimal concentrations; (3) PMA enhanced fMet-Leu-Phe-induced migration, increasing the speed of locomotion but not affecting shape changes induced by fMet-Leu-Phe; (4) the number of fMet-Leu-Phe-specific receptors expressed on the PMN membrane was not altered. Intermediate concentrations of PMA (1.