Source of the arachidonic acid released on stimulation of rat basophilic leukemia cells.

Triggering of rat basophilic leukemia cells for histamine secretion is accompanied by arachidonic acid release. We studied the source of this arachidonic acid released after IgE or calcium ionophore A23187 stimulation. The 48-hr culture of the cells with [14C]arachidonic acid resulted in labeling of the phospholipids to constant specific activity.

Phospholipase A2 stimulation during cell secretion in rat basophilic leukemia cells.

The bridging of IgE receptors on rat basophilic leukemia cells (RBL-2H3) results in a number of biochemical events that accompany histamine secretion. Prominent among these is the release of arachidonic acid from cellular phospholipids, which could be due to the activation of phospholipase enzymes. In the present experiments we studied the intracellular activation of phospholipase A2 (PLA2) during histamine release.

Synthesis of platelet-activating factor from human polymorphonuclear leukocytes: regulation and pharmacological approaches.

Human polymorphonuclears release a platelet-activating factor (PAF-acether) when challenged with various stimuli. PAF-acether is a mediator that is synthesized during cell activation in a process in which a phospholipase A2 and an acetyltransferase take part. These enzymes are finely regulated and accordingly PAF-acether release may be modulated.

Effect of monodansylcadaverine on the synthesis of phosphatidylinositol by rabbit neutrophils.

The present results show that the addition of monodansylcadaverine to rabbit neutrophils stimulates the incorporation of both [3H]inositol and [3H]glycerol into phosphatidylinositol. Monodansylcadaverine also induces the accumulation of phosphatidylinositol 4-phosphate, phosphatidic acid and diacylglycerol. These effects are all dose-dependent and occur at concentrations of monodansylcadaverine which are known to inhibit receptor-mediated endocytosis.

Dansylcadaverine and rimantadine inhibition of phagocytosis, PAF-acether release, and phosphatidylcholine synthesis in human polymorphonuclear leukocytes.

The effect of dansylcadaverine, amantadine, and rimantadine on phagocytosis, release of PAF-acether, phospholipid methylation, and phosphatidylcholine formation by the cholinephosphotransferase pathway was assessed in human peripheral polymorphonuclear leukocytes. All of the drugs induced a dose-dependent and reversible inhibition in the uptake of complement-coated zymosan particles as well as a reduction in the release of PAF-acether. Simultaneously, a marked reduction in the formation of phosphatidylcholine was observed.

Phospholipid turnover during phagocytosis in human polymorphonuclear leucocytes.

We have previously observed that the phagocytosis of zymosan particles coated with complement by human polymorphonuclear leucocytes is accompanied by a time- and dose-dependent inhibition of phosphatidylcholine synthesis by transmethylation [García Gil, Alonso, Sánchez Crespo & Mato (1981) Biochem. Biophys. Res.

Regulation by guanosine 3':5'-cyclic monophosphate of phospholipid methylation during chemotaxis in Dictyostelium discoideum.

In Dictyostelium discoideum, the chemoattractant cyclic AMP activates the enzyme guanylate cyclase, giving a brief up to 10-fold increase in the intracellular cyclic GMP content. The addition of physiological cyclic GMP concentrations to a homogenate of D. discoideum cells markedly increased the incorporation of the 3H-labeled methyl group from S-adenosyl-L-[methyl-3H]methionine into mono- and dimethylated phosphatidylethanolamine and phosphatidylcholine.

[Total ureteral rupture caused by closed abdominal injury in polytraumatized patients].

The authors present a case of complete ureteral rupture, after closed, abdominal traumatism in a patient suffering from multiple traumatisms. They point out the slight number of cases published in the literature as well as the frequency of its delayed diagnosis due to few or no symptoms, particularly when associated with visceral ruptures or bone fractures which may conceal the picture. They recommend the I.