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Human platelets stimulated by epinephrine undergo enhanced turnover of phosphatidylinositol 4,5-bisphosphate, accumulate inositol trisphosphate, diacylglycerol, and phosphatidic acid, and phosphorylate a 47-kDa protein. All of these phenomena indicate stimulation of phospholipase C. These responses are blocked completely by inhibitors of alpha 2-adrenergic(More)
Recently, we demonstrated that human monocyte-derived macrophages (MDM) treated with chloroquine or ammonium chloride had markedly increased antifungal activity against the AIDS-related pathogen Cryptococcus neoformans. Both of these agents raise the lysosomal pH, which suggested that the increased antifungal activity was a function of alkalinizing the(More)
We describe a new method for subcellular fractionation of human neutrophils. Neutrophils were disrupted by nitrogen cavitation and the nuclei removed by centrifugation. The postnuclear supernatant was applied on top of a discontinuous Percoll density gradient. Centrifugation for 15 min at 48,000 g resulted in complete separation of plasma membranes,(More)
Chronic granulomatous disease (CGD) is an inherited disorder of host defense due to the inability of the phagocyte to generate toxic oxygen metabolites upon appropriate stimulation. The disorder is heterogeneous even within the confines of a defective respiratory burst oxidase function, and may arise from a biochemical lesion at either the receptor, the(More)
CD14 is a signaling receptor for both gram-negative bacterial lipopolysaccharide (LPS) and mycobacterial lipoarabinomannan (LAM) that lacks terminal mannosyl units (AraLAM). In contrast, terminally mannosylated LAM (ManLAM) binds the macrophage mannose receptor (MMRc), although the ability of the MMRc to serve as a signaling receptor has not been previously(More)
Neutropenia is considered a significant risk factor for invasive aspergillosis but is almost always associated with concurrent thrombocytopenia. Studies determined that platelets, like neutrophils, attached to cell walls of the invasive hyphal form of Aspergillus fumigatus. Organisms were damaged as shown by loss of cell wall integrity in scanning laser(More)
It has long been appreciated that polymorphonuclear leukocytes (PMN) kill Cryptococcus neoformans, at least in part via generation of fungicidal oxidants. The aim of this study was to examine the contribution of nonoxidative mechanisms to the inhibition and killing of C. neoformans. Treatment of human PMN with inhibitors and scavengers of respiratory burst(More)
T lymphocytes from aged donors function poorly, but the biochemical basis for the defect remains uncertain. We tested the hypothesis that T cells from old mice had a diminished ability to transmit extracellular signals into the cytoplasm, by measuring intracellular free calcium concentrations (Cai) in T cells stimulated by the polyclonal activator(More)
Removal of calcium from thrombospondin with EDTA results in a decrease in the intensity of the negative CD peak between 200 and 250 nm. Quantitative analysis of the CD spectrum of thrombospondin indicates that thrombospondin contains approximately 11% alpha-helix, 43% beta-sheet, and 46% random coil in the presence of calcium and that a small change in(More)