The coagulant activity of tissue factor (TF) in the membranes of cultured cells is increased after physical disruption of the cells, and a similar increase can be elicited by treatment of cell cultures with calcium ionophore and calcium. We observed that the supernatants of cultures treated with calcium and ionophore 4-Br-A23187 contained more TF activity than those of control cultures. Phase c...

The addition of the calcium ionophore A23187 to rabbit neutrophils increases the amount of actin associated with the cytoskeleton regardless of the presence or absence of calcium in the incubation medium. In the presence of extracellular calcium, the effect of A23187 is biphasic with respect to concentration. The action of the ionophore is rapid, transient, and is inhibited by pertussis toxin, ...

Macrophages remove deteriorating cells (those undergoing apoptosis and oxidation) via poly-N-acetyllactosaminyl chains on CD43 caps, a major cell-surface glycoprotein. Unusually high intracellular calcium levels are also deteriorating for cells and tissue. Here we artificially elevated calcium levels in cells and examined the mechanism by which this elevation was resolved by macrophages. Result...

Bisphosphonates are antiatherosclerotic, suppress monocyte-macrophages, and modulate proinflammatory mediators. Prostaglandin (PG) E(2), thromboxane (TX) A(2), and cyclooxygenase-2 (COX-2) enzyme are involved in inflammation and atherosclerosis. We studied the effects of four bisphosphonates (etidronate, clodronate, tiludronate, and alendronate) on PGE(2) and TXB(2) production in human whole bl...

The erythrocytes from a patient with Scott syndrome, a bleeding disorder characterized by an isolated defect in expression of platelet procoagulant activity, have been studied. When incubated with the calcium ionophore A23187, Scott syndrome red blood cells (RBCs) expressed less than 10% of the prothrombinase (enzyme complex of coagulation factors Va and Xa) activity of A23187-treated RBCs obta...

Background: Parthenogenetic activation is a possible way to produce homogeneous embryos with the some ploidy. Probably such embryos could be used in other areas of biotechnology. Calcium signals are known as important regulators of oocyte activation. Extracellular calcium is required for initiation of meiotic resumption and development. Calcium ionophore A23187 is known to elevate intracellular...

Activated extracellular-signal-regulated kinase (Erk) phosphorylates and activates downstream kinases including ribosomal S6 kinase 2 (Rsk2/RPS6KA3) and mitogen- and stress-activated kinase 1 (Msk1, RPS6KA5). Rsk2 plays an important role in neuronal plasticity, as patients with Coffin-Lowry syndrome, where Rsk2 is dysfunctional, have impaired cognitive function. However, the relative role of ne...

The effects of somatostatin (SRIF) on glucagon release have been studied in the monolayer culture of newborn rat pancreas. It was found that SRIF inhibited glucagon release rapidly and in a dose dependent manner at concentrations of 1-1000 ng/ml. SRIF inhibited glucagon release under basal conditions and after stimulation by arginine, 3-isobutyl-1-methylxanthine (IBMX), high Ca++ concentrations...

The effects of adenosine, adenosine deaminase (ADA), and an irreversible ADA inhibitor 2'-deoxycoformycin (DCF) on granulocyte aggregation in response to four different stimuli: the synthetic chemotaxin N-formyl-met-leu-phe (FMLP), zymosan-activated plasma (ZAP), the calcium ionophore A23187, and phorbol myristate acetate (PMA) were studied. Adenosine inhibited granulocyte aggregation in respon...

Experiments were performed to determine the effect of ouabain on the release of relaxing factor(s) from cultured endothelial cells, and its action on the effect of the relaxing factor(s) on arterial smooth muscle. A column of porcine aortic endothelial cells grown on microcarrier beads in suspension culture was perfused with modified Krebs-Ringer bicarbonate solution. The release of relaxing fa...