Rabbit neutrophils were stimulated with the chemotactic peptide fMet-Leu-Phe in the presence of the methyltransferase inhibitors homocysteine (HCYS) and 3-deazaadenosine (3-DZA) . HCYS and 3-DZA inhibited chemotaxis, phospholipid methylation, and protein carboxymethylation in a dose-dependent manner . The chemotactic peptide-stimulated release of [t "C]arachidonic acid previously incorporated i...

Rabbit neutrophils were stimulated with the chemotactic peptide fMet-Leu-Phe in the presence of the methyltransferase inhibitors homocysteine (HCYS) and 3-deazaadenosine (3-DZA) . HCYS and 3-DZA inhibited chemotaxis, phospholipid methylation, and protein carboxymethylation in a dose-dependent manner . The chemotactic peptide-stimulated release of [t "C]arachidonic acid previously incorporated i...

Simultaneous measurements of membrane capacitance and intracellular calcium concentration were used to examine the calcium dependence of exocytosis in single acinar cells from mouse lacrimal gland and to establish the quantitative relation between calcium concentration and rate of exocytosis. Application of adrenergic or muscarinic agonists elevated intracellular calcium and evoked exocytosis, ...

LY 255283 [(1-(5-ethyl-2-hydroxy-4-(6-methyl-6-)1H-tetrazol-5-yl)-heptyloxy) phenyl)ethanone], a specific leukotriene B(4) (LTB(4)) receptor antagonist, inhibited the production of LTB(4) in human peripheral blood polymorphonuclear leukocytes (PMNL) and in monocytes activated by calcium ionophore A23187. In human monocytes activated by ionophore it inhibited also the production of thromboxane B...

Concentrations of the divalent cation ionophore, A23187, optimal for the transformation of human and pig lymphocytes, were cytotoxic to lymphocytes from rats and mice. The biochemical effects associated with A23187-induced cytolysis in rat thymocytes included inhibition of [3H]uridine uptake and incorporation into macromolecules and stimulation of [14C]-alpha-aminoisobutyric acid uptake. The bi...

The calcium-sensitive fluorescent probe chlorotetracycline was used to monitor calcium movement in human platelets. The chlorotetracycline fluorescence signal is a linear measure of the level of free calcium in the dense tubules and in the mitochondria, with probe sensitivity in the millimolar range. Experiments perturbing the system with the calcium ionophore A23187 shows that the level of fre...

Uptake of calcium by a membrane fraction enriched in basolateral plasma membrane vesicles from rat small intestine has been investigated using a rapid filtration technique. Calcium accumulation is stimulated by ATP and released by the calcium ionophore A23187. Kinetic studies indicate a calcium concentration of 28 nM for half-maximal stimulation of ATP-driven uptake. Transport is minimally inhi...

The present study was undertaken to assess the effect of different chemical activators along with 6-DMAP on in vitro matured caprine oocytes. From 4332 ovaries, 14235 cumulus oocyte complexes (COCs) were collected which were matured in TCM-199 medium containing follicle stimulating hormone (FSH) (5 µg/ml), Leutinizing hormone (LH) (10 µg/ml), oestradiol-17β (1 µg/ml) supplemented with 10% fetal...