Ultrastructural characterization and morphometric analysis of human eosinophil degranulation

1985 ◽  
Vol 73 (1) ◽  
pp. 33-48
Author(s):  
W.R. Henderson ◽  
E.Y. Chi
Keyword(s):  
Morphometric Analysis ◽  
Plasma Membranes ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Cell Periphery ◽  
Granule Formation ◽  
Human Eosinophil ◽  
Transmission Electron ◽  
Eosinophil Degranulation

Human eosinophil degranulation induced by the calcium ionophore A23187 was examined by transmission and scanning electron microscopy, and morphometric analysis. After incubation with A23187, eosinophil degranulation was characterized by granule movement to the cell periphery and pentalaminar membrane fusion between perigranular and plasma membranes. As adjacent granules fused they became swollen and vesiculated; their contents were released into large cytoplasmic vacuoles, which communicated extracellulary through surface pores. Extracellular release of eosinophil peroxidase without release of lactate dehydrogenase occurred after treatment with the ionophore. Morphometric analysis of the transmission electron micrographs indicated a significant reduction of cytoplasmic granules in the degranulated cells. There was a loss primarily of larger granules and alternatively an increase in the smaller-sized granules (less than 0.1 micron2), suggesting the possibility that exocytosis of mature granules is accompanied by new cytoplasmic granule formation.

Localization of a pigment-containing structure near the surface of Xenopus eggs which contracts in response to calcium

Development ◽  
1983 ◽  
Vol 76 (1) ◽  
pp. 51-65
Author(s):  
R. W. Merriam ◽  
R. A. Sauterer
Keyword(s):  
Calcium Ion ◽  
Cytochalasin B ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Isolation Medium ◽  
Whole Cells ◽  
Transmission Electron ◽  
Structural Connections ◽  
Contractile Structure

Contractions in surface structures of Xenopus eggs have been induced by application of the calcium ionophore A23187 or calcium ion. Local applications have shown that the contractile structure is present in both animal and vegetal hemispheres. It is, however, much stronger in the animal hemisphere and pigment embedded in it there defines the animal half. The injection of cytochalasin B (CB) into whole cells or the application of the antibiotic to half cells cannot prevent the induced contractions. By experimental means, the contraction of a deeper, pigment-containing structure can be uncoupled from a thin, more superficial and relatively pigment-free layer on the egg surface. By this means it has been possible to establish that the CB-resistant contraction is due, at least partially, to a structurally distinguishable layer subjacent to the outer egg cortex. Scanning and transmission electron microscopy demonstrate a dense grainy matrix near the egg surface in which pigment granules but little yolk are embedded. This structure is much thicker in the pigmented hemisphere. The presence of calcium ions in an isolation medium are shown to cause a loosening or dissolution of the structural connections between the dense, contractile structure near the surface and the cytoskeleton of the endoplasm.

scholarly journals Changes in cytoplasmic calcium determine the secretory response to extracellular cations in human parathyroid cells: a confocal microscopy study using FM1-43 dye

2000 ◽  
Vol 352 (2) ◽  
pp. 353-361 ◽  
Author(s):  
Radu MIHAI ◽  
Teresa LAI ◽  
George J. SCHOFIELD ◽  
John R. FARNDON
Keyword(s):  
Confocal Microscopy ◽  
Plasma Membranes ◽  
Calcium Concentration ◽  
Membrane Surface ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Cytoplasmic Calcium ◽  
Acetoxymethyl Ester ◽  
Prolonged Incubation

Whether activation of the calcium receptor (CaR) modulates secretory events was investigated by real-time fluorescence and confocal microscopy using fura 2 and FM1-43 fluorescent dye. Two paradigms were used: human parathyroid cells, which are stimulated by a step from a high to a low extracellular calcium concentration ([Ca2+]ext), and rMTC6-23 cells, a rat medullary thyroid carcinoma cell line whose secretion is stimulated by an increase in [Ca2+]ext. Parathyroid cells were dispersed from parathyroid adenomas removed from 18 patients with primary hyperparathyroidism. In both cell types, incubation with FM1-43 (2µM) resulted in staining of the plasma membranes, which was rapidly increased following changes in [Ca2+]ext known to stimulate secretion. A high [Ca2+]ext and lanthanum (La3+) decreased the membrane-associated FM1-43 fluorescence. Prolonged incubation (5–30min) in the presence of FM1-43 resulted in accumulation of the dye in the cytoplasm, its granular distribution suggesting targeting of the secretory compartment. These data suggest that FM1-43 fluorescence is determined by: (i) changes in cell membrane surface area associated with secretion-associated events, (ii) displacement/quenching by extracellular cations and (iii) endocytosis of the dye. In parathyroid cells, a rise in FM1-43 fluorescence occurred during incubation in a high (inhibitory) [Ca2+]ext if the cytoplasmic calcium concentration ([Ca2+]i) was decreased by the calcium chelator BAPTA/AM [bis-(o-aminophenoxy)ethane-N,N,Nƀ,Nƀ-tetra-acetic acid tetrakis(acetoxymethyl ester)] (10–50µM). Alternatively, the expected rise in FM1-43 fluorescence did not occur during incubation in a low (stimulatory) [Ca2+]ext if [Ca2+]i was increased by addition of the calcium ionophore A23187 (10–25µM). These data suggest that [Ca2+]i, rather than the absolute value of [Ca2+]ext, is the main modulator of secretion from parathyroid cells.

scholarly journals The course of the acrosome reaction in guinea-pig sperm

1982 ◽  
Vol 54 (1) ◽  
pp. 161-171
Author(s):  
D.P. Green
Keyword(s):  
Guinea Pig ◽  
Membrane Fusion ◽  
Osmotic Pressure ◽  
Acrosome Reaction ◽  
Plasma Membranes ◽  
Calcium Ionophore ◽  
Colloid Osmotic Pressure ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Sequence Of Events

The acrosome reaction in guinea-pig sperm is accompanied by a marked cavitation of the acrosomal contents. Two divergent views are held as to whether this cavitation precedes or follows the membrane fusion that occurs in the reaction. To distinguish between these 2 views cavitation was induced in media containing a colloid, either Ficoll 70 or inulin, either by inducing a normal acrosome reaction using the calcium ionophore A23187 or by using the detergent Triton X100. Both Ficoll 70 and inulin, when incorporated into media of normal osmolality, were able to suppress various features of the cavitation. Complete retention of acrosomal shape was achieved in sperm treated with detergent in 30% (W/V) Ficoll 70 solution despite the absence of the limiting acrosomal and plasma membranes. This evidence supports the suggestion that the cause of the cavitation is a colloid osmotic pressure within the acrosomal matrix. This in turn supports one of the 2 proposed mechanisms for the temporal sequence of events occurring in the acrosome reaction.

scholarly journals Interleukin-5 Potentiates Sulfidopeptide Leukotriene Production by Human Eosinophils

1994 ◽  
Vol 3 (1) ◽  
pp. 53-55 ◽  
Author(s):  
A. J. M. Van Oosterhout ◽  
A. Van Der Poel ◽  
L. Koenderman ◽  
D. Roos ◽  
F. P. Nijkamp
Keyword(s):  
Priming Effect ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Human Eosinophil ◽  
Interleukin 5 ◽  
Differentiation Factor ◽  
Significant Stimulation ◽  
Dose Dependent

Interleukin-5 (IL-5) has been shown to be a selective eosinophil growth and differentiation factor. In the present study, the effect of recombinant human IL-5 on human eosinophil sulfidopeptide leukotriene production was investigated. IL-5 did not affect leukotriene synthesis in unstimulated eosinophils. However, IL-5 potentiated leukotriene synthesis by eosinophils stimulated with serum treated zymosan (STZ) or the calcium ionophore A23187 by 69% and 135%, respectively. The priming effect of IL-5 was dose dependent, with significant stimulation occurring at 1 000 U/ml for STZ and 100-1 000 U/ml for A23187. Pre-incubation with IL-5 did not increase leukotriene synthesis further.

Time course of endothelial dysfunction and myocardial injury during coronary arterial occlusion

1991 ◽  
Vol 261 (3) ◽  
pp. H874-H881 ◽  
Author(s):  
G. E. Viehman ◽  
X. L. Ma ◽  
D. J. Lefer ◽  
A. M. Lefer
Keyword(s):  
Time Course ◽  
Calcium Ionophore ◽  
Arterial Occlusion ◽  
Endothelial Damage ◽  
Calcium Ionophore A23187 ◽  
Induced Response ◽  
Ionophore A23187 ◽  
Myeloperoxidase Activity ◽  
Neutrophil Accumulation ◽  
Transmission Electron

The time course of the effects of permanent myocardial ischemia without reperfusion on the coronary vascular endothelium and myocardium were investigated in anesthetized cats. The left anterior descending (LAD) coronary artery was occluded for 1.5, 3.0, 4.5, or 6.0 h. Coronary rings from the ischemic LAD and the nonischemic left circumflex (LCX) arteries were tested for their responsiveness to the endothelium-dependent vasodilators acetylcholine (ACh, 0.1-100 nM) and the calcium ionophore A23187 (1-1,000 nM), and the endothelium-independent vasodilator sodium nitrite (NaNO2, 0.1-100 microM). Vasorelaxation was not significantly impaired in response to ACh after 1.5 h of ischemia and only moderately impaired after 3.0 h of ischemia (63 +/- 5% of control). However, after 4.5 h of ischemia the ACh-induced response was decreased to 33 +/- 4% of control and further declined to 31 +/- 4% of control after 6.0 h (P less than 0.001 from 1.5 h). There was no significant decrease in LCX ring vasorelaxant responses to vasodilators at all times, and the LAD rings only showed a moderately decreased response to NaNO2 after 6.0 h of ischemia (82 +/- 4% relaxation, P less than 0.05). Transmission electron microscopy revealed very little endothelial damage at 4.5 and 6.0 h, with only some subendothelial swelling noted. Damage to the myocardium did not become significant until after 4.5 h of ischemia, and cardiac myeloperoxidase activity, indicative of neutrophil accumulation, was not significant at any time.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth factors and the primary cilium in BALB/c 3T3 cells

1987 ◽  
Vol 45 ◽  
pp. 830-831
Author(s):  
R. W. Tucker ◽  
N. S. More ◽  
S. Jayaraman
Keyword(s):  
Growth Factors ◽  
Primary Cilium ◽  
Cultured Cells ◽  
Morphological Changes ◽  
Calcium Ionophore ◽  
Growth Stimulation ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
3T3 Cells ◽  
Microtubule Depolymerization

The mechanisms by which polypeptide growth factors Induce DNA synthesis in cultured cells is not understood, but morphological changes Induced by growth factors have been used as clues to Intracellular messengers responsible for growth stimulation. One such morphological change has been the transient disappearance of the primary cilium, a “9 + 0” cilium formed by the perinuclear centriole in interphase cells. Since calcium ionophore A23187 also produced both mitogenesis and ciliary changes, microtubule depolymerization might explain ciliary disappearance monitored by indirect immunofluorescence with anti-tubulin antibody. However, complete resorption and subsequent reformation of the primary cilium occurs at mitosis, and might also account for ciliary disappearance induced by growth factors. To settle this issue, we investigated the ultrastructure of the primary cilium using serial thin-section electron microscopy of quiescent BALB/c 3T3 cells before and after stimulation with serum.

Inhibition of Platelet Aggregation by Ethanol in Vitro Shows Specificity for Aggregating Agent Used and Is Influenced by Platelet Lipid Composition

1982 ◽  
Vol 48 (01) ◽  
pp. 049-053 ◽  
Author(s):  
C G Fenn ◽  
J M Littleton
Keyword(s):  
Platelet Aggregation ◽  
Lipid Composition ◽  
Saturated Fatty Acids ◽  
Calcium Ionophore ◽  
Cholesterol Content ◽  
Membrane Lipid ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Increased Sensitivity

SummaryEthanol at physiologically tolerable concentrations inhibited platelet aggregation in vitro in a relatively specific way, which may be influenced by platelet membrane lipid composition. Aggregation to collagen, calcium ionophore A23187 and thrombin (low doses) were often markedly inhibited by ethanol, adrenaline and ADP responses were little affected, and aggregation to exogenous arachidonic acid was actually potentiated by ethanol. Aggregation to collagen, thrombin and A23187 was inhibited more by ethanol in platelets enriched with saturated fatty acids than in those enriched with unsaturated fats. Platelets enriched with cholesterol showed increased sensitivity to ADP, arachidonate and adrenaline but this increase in cholesterol content did not appear to influence the inhibition by ethanol of platelet responses. The results suggest that ethanol may inhibit aggregation by an effect on membrane fluidity and/or calcium mobilization resulting in decreased activity of a membrane-bound phospholipase.

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