Exposure of isolated bovine neutrophils to partially purified Pasteurella haemolytica leukotoxin caused increased synthesis of leukotriene B4 (LTB4) but not thromboxane B2 (TXB2) from endogenous arachidonic acid. Synthesis of LTB4 was closely correlated with leukotoxin-induced neutrophil lysis. At low toxin concentrations, LTB4 production lagged behind leukotoxin-induced neutrophil lysis over a...

When it comes to joint pain, it is mostly the cartilage that is inflamed and chronic headaches often result from neural inflammatory processes. Overcoming this pain will often seem impossible. What is little known: Superhormones, which can regulate the hormonal balance of the body, exist – these are eicosanoids, derivatives of arachidonic acid, an omega-6 fatty acid. What effect do the arachido...

Following stimulation with adenosine diphosphate (ADP), collagen, or arachidonic acid, unstirred human platelet suspensions bind 125I-fibrinogen in a reaction that reaches completion within 30 min. Scatchard analysis of these binding data reveals two sets of binding sites with all 3 agents: a high affinity site (Kd 0.029-0.045 microM) binding 1000-1600 fibrinogen molecules per platelet, and a l...

Activation of platelets induces the formation of phosphatidic acid, which results from the combined actions of a phosphatidylinositol-specific phospholipase C and a 1,2-diacylglycerol kinase. It has been proposed that this phosphatidic acid leads in some way to the subsequent production of arachidonic acid. The present studies reveal the existence of a particulate phospholipase Az enzyme that a...

UNLABELLED Acute fatty liver of pregnancy (AFLP) is a rare disorder which is fatal if not recognized and treated early. Delivery of the feto-placental unit results in dramatic improvement in maternal liver function, suggesting a role for the placenta. However, the mechanisms by which defects in the fetus or placenta lead to maternal liver damage are not well understood and form the focus of thi...

12-Lipoxygenase and cyclooxygenase 1 are the dominating enzymes that metabolize arachidonic acid in human platelets. In addition to the conversion of arachidonic acid to 12(S)-hydroxyeicosatetraenoic acid, 12-lipoxygenase can also utilize 5(S)-hydroxyeicosatetraenoic acid and 15(S)-hydroxyeicosatetraenoic acid to form 5(S), 12(S)-dihydroxyeicosatetraenoic acid and 14(R), 15(S)-dihydroxyeicosate...

Escherichia coli K1 meningitis occurs following penetration of the blood-brain barrier, but the underlying mechanisms involved in E. coli penetration of the blood-brain barrier remain incompletely understood. We have previously shown that host cytosolic phospholipase A(2)α (cPLA(2)α) contributes to E. coli invasion of human brain microvascular endothelial cells (HBMEC), which constitute the blo...

The influence of the leukotoxin of Pasteurella haemolytica on the generation of arachidonic acid metabolites by bovine polymorphonuclear leukocytes (PMNs) was investigated. PMNs released 5-, 12-, and 15-hydroxyeicosatetraenoic acids (5-, 12-, and 15-HETE) and leukotriene B4 (LTB4) upon stimulation with arachidonic acid. The leukotoxin preparations dose dependently enhanced the release of the 5-...

Release of arachidonic acid by the membrane phospholipase and metabolism by the 5-lipoxygenase pathway was examined in human polymorphonuclear leukocytes (PMNs). The 5-lipoxygenase pathway is activated when PMNs are given arachidonic acid in ethanol and there is extensive metabolism to 5-hydroxyicosatetraenoic acid (5-HETE) and leukotriene B4 (LTB4). This activation event was shown to be altere...