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Biomedical subjects

G Marone

Publications and source records attributed to G Marone.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Adenosine-adenosine deaminase modulation of histamine release from human basophils in vitro.

Since extracellular adenosine is a physiologically important regulator of adenylate cyclase and cell function in various mammalian tissues, we have examined the effect of adenosine on histamine release from human basophils. Adenosine inhibited IgE-mediated histamine release by its ability to increase leukocyte cyclic AMP levels; the same concentrations of adenosine which inhibited histamine release increased the cyclic AMP level of mixed leukocytes. Inhibition of histamine release was also observed with an adenosine deaminase (ADA) inhibitor [erythro-9-(2-hydroxy-3-nonyl)-adenine: EHNA] in the presence of autologous serum. We suggest that the adenosine-ADA system normally modulates histamine release and that this contributes to the severe combined immune deficiency (SCID) associated with a lack of ADA.

Adenosine↗
PubMedDate not supplied

Modulation of beta-adrenergic receptor by hydrocortisone in human polymorphonuclear leukocytes.

We have examined the influence of isoproterenol and hydrocortisone on the cycle AMP content and lysosomal enzyme release from highly purified human polymorphonuclear leukocytes. It was found that isoproterenol, although a potent stimulus for cAMP accumulation in human lymphocytes, had only marginal effects on both cAMP content of PMN and enzyme release. Since corticosteroids have been reported to increase the response to beta-agonists in various tissues, it was considered that some of the anti-inflammatory potential of corticosteroids might be related to enhancing the response of PMN to beta-agonists. The influence of hydrocortisone on the response to isoproterenol was accordingly examined. It was found that hydrocortisone did in fact augment the isoproterenol-induced increase in cAMP content. In contrast to the potentiation of cAMP accumulation caused by hydrocortisone and isoproterenol together, the two agents produced only an additional inhibition of enzyme release. Since the inhibition of lysosomal enzyme release from human PMN did not closely reflect the changes observed in the cAMP content, a possible compartmentalization of intracellular cAMP is suggested.

Adenylyl Cyclases↗
PubMedDate not supplied

Cyclosporin A inhibits the release of histamine and peptide leukotriene C4 from human lung mast cells.

We investigated the effect of cyclosporin A (CsA) on in vitro release of chemical mediators from mast cells purified from human lung tissues. CsA (3 X 10(-2) to 1 microgram/ml) dose-dependently inhibited IgE-mediated release of histamine and peptide leukotriene C4 (LTC4) from human lung mast cells. The same concentrations of CsA also inhibited the release of histamine from lung mast cells challenged with the Ca2+ ionophore A23187. Therefore, CsA in pharmacological concentrations inhibits the IgE- and non-IgE-mediated release of inflammatory mediators from mast cells purified from human lung tissues.

Calcimycin↗
PubMedDate not supplied

Functional and biochemical evidence of a specific adenosine A2/Ra receptor on human platelets.

5'-N-ethylcarboxamideadenosine (NECA) greater than 2-chloroadenosine greater than adenosine greater than (-)-N6-(R-phenyl-isopropyl)-adenosine [(-)-R-PIA] greater than (+)-N6-(S-phenyl-isopropyl)-adenosine [(+)-S-PIA] inhibited in vitro human platelet aggregation in a dose-dependent fashion. 6-nitrobenzylthioinosine and dipyridamole, which inhibit adenosine uptake, and erythro-9-(2-hydroxy-3-nonyl)-adenine, which blocks adenosine metabolism, did not impair the inhibition induced by NECA and adenosine. 8-phenyltheophylline and theophylline, two competitive antagonists of adenosine receptors, blocked the inhibition of platelet aggregation caused by NECA and adenosine. NECA greater than 2-chloroadenosine greater than adenosine greater than (-)-R-PIA greater than (+)-S-PIA increased platelet cyclic adenosine monophosphate (cAMP) levels in a dose-dependent fashion. A significant linear correlation (r = 0.70, p less than 0.001) was found between the increase of platelet cAMP and the inhibition of platelet aggregation induced by adenosine and its analogs. 8-phenyltheophylline, which is a competitive antagonist of adenosine in platelets, also blocked the cAMP accumulation caused by NECA. These data suggest that NECA and other adenosine analogs activate a specific cell surface adenylate cyclase-linked adenosine receptor whose properties are similar to those of an adenosine A2/Ra receptor.

Adenosine↗
PubMedDate not supplied

Betamethasone increases the beta-adrenergic receptor density of human polymorphonuclear leukocytes.

Prolonged incubation (18h) of human polymorphonuclear leukocytes (PMNs) with betamethasone (BT) (10(-7) M) increased (3H)-DHA binding to human PMN membranes, apparently causing an increase in the number of beta-adrenergic receptors. Inhibition of this effect by cycloheximide (2 micrograms/ml) suggests that it is dependent on protein synthesis. BT had no effect on basal levels of cAMP in PMNs, but synergistically potentiated the increase in cyclic AMP (cAMP) induced by isoproterenol. Propranolol completely abolished the synergistic effect of BT plus isoproterenol, suggesting that the potentiating effect of BT on cAMP metabolism required the activation of beta-adrenergic receptors. Thus, BT increased the number of beta-adrenergic receptors in human PMN membranes and potentiated the cAMP changes induced by beta-agonists.

Betamethasone↗
PubMedDate not supplied

Cardiovascular effects of histamine infusion in man.

Histamine (H) is stored in man in the cardiovascular as well as in other systems, from where it can be released under exposure to immunologic and nonimmunologic stimuli. To understand better the hemodynamic changes produced in man by endogenous H release, we infused H for 3.5-7 min at the rate of 0.4 microgram/kg/min i.v. in four patients with normal left ventricular (LV) function undergoing diagnostic cardiac catheterization. We observed a significant fall in systolic, diastolic, and mean aortic pressure, systemic vascular resistance, LV end-diastolic pressure, and stroke index, and a significant rise in heart rate, cardiac output, and LV dP/dtmax, with small changes in mean pulmonary arterial pressure and pulmonary vascular resistance. During infusion there was also a significant rise in plasma H, epinephrine, and norepinephrine. All hemodynamic changes started 1-2 min after the beginning of H infusion and reverted to normal within 5 min from the end of the infusion. Subjective complaints were mild and transient in all patients. One patient progressed from first- to third-degree atrioventricular block, with prompt recovery of 1:1 atrioventricular conduction at the end of infusion. Thus, exogenous H administration in man at the rate of 0.4 microgram/kg/min produces significant and transient hemodynamic changes, mainly represented by systemic hypotension, tachycardia, and increased LV performance. These latter can be attributed to the associated increase in sympathoadrenergic activity, although a direct cardiac effect of H cannot be excluded.

Aged↗
PubMedDate not supplied

Mepindolol reduces myocardial necrosis in rats with coronary artery occlusion.

Mepindolol is a newly developed beta-adrenergic blocking agent reported to counteract the chronotropic effect of catecholamines, with only little effect on contractility. This study was designed to assess whether or not mepindolol is effective in reducing infarct size. Accordingly, 16 rats, serving as controls, underwent coronary artery occlusion and did not receive any treatment; an additional 19 were treated with mepindolol (1 mg/kg s.c. t.i.d.) for 48 h. Finally, a third group (n = 18) underwent sham operation. Forty-eight hours later, infarct size was calculated from left ventricular creatine phosphokinase activity and found to average 52.4 +/- 7.8% (mean +/- SEM) of the left ventricle in control rats and 35.6 +/- 5.4% in treated rats (p less than 0.05). Left ventricular phospholipid content averaged 0.79 +/- 0.08 microgram P/mg protein in sham-operated rats and 0.61 +/- 0.04 microgram P/mg protein in control animals. In contrast, in mepindolol-treated rats, phospholipid concentration was 0.70 +/- 0.04 microgram P/mg protein (p less than 0.05), this suggesting a protective effect of the drug on ischemia-induced phospholipid degradation. The long-term effect of mepindolol on left ventricular hydroxyproline concentration was assessed 21 days post-coronary occlusion. Infarct size calculated by this method was 30.2 +/- 4.8% of left ventricle in 21 control animals and 18.2 +/- 4.2% in 28 treated rats (p less than 0.05), indicating that, as for the acute necrosis, the extent of scar development after coronary artery occlusion can be reduced by mepindolol.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Endogenous superallergen protein Fv interacts with the VH3 region of IgE to induce cytokine secretion from human basophils.

BACKGROUND: Protein Fv is an endogenous protein, synthesized in liver and largely released in the digestive tract during acute and chronic viral hepatitis, that binds to immunoglobulin (Ig) from various mammalian and nonmammalian species. METHODS: Basophils obtained from normal subjects were purified by a double Percoll gradient and elutriation. The secretion of histamine induced by protein Fv was assayed by a fluorometric technique, the extracellular protein levels of IL-4 and IL-13 were measured by ELISA, and IL-4 mRNA levels were evaluated by RT-PCR. RESULTS: Protein Fv concentration-dependently induced histamine and IL-4 and IL-13 release from purified basophils. IL-4 mRNA, constitutively present in basophils, was increased after stimulation by protein Fv. Histamine and IL-4 secretion from basophils, but not histamine and IL-13 release, activated by protein Fv was significantly correlated (rs = 0.70, p<0.001). Basophils from which IgE had been dissociated by brief exposure to lactic acid no longer released IL-4 in response to protein Fv and anti-IgE. Two preparations of human VH3(+) monoclonal IgM inhibited protein Fv-induced secretion of IL-4 and histamine from basophils. In contrast, VH6(+) monoclonal IgM did not inhibit the release of mediators caused by protein Fv. CONCLUSIONS: These results indicate that protein Fv, which acts as an endogenous superallergen, interacts with the VH3 domain of IgE to induce the synthesis and release of IL-4, IL-13 and the secretion of histamine from basophils.

Basophils↗
PubMedDate not supplied

Novel autocrine and paracrine loops of the stem cell factor/chymase network.

BACKGROUND: The aim of this study was to investigate whether the secretory granules of human mast cells store stem cell factor (SCF). We also addressed the question whether mast cell chymase, a chymotrypsin-like protease, also present in the secretory granules of human mast cells cleaves SCF at the peptide bound between Phe 158 and Met159. METHODS: The skin samples were obtained from patients with mastocytosis, undergoing skin biopsy for diagnostic purposes. Mast cells were isolated and purified from human lung parenchyma (human lung mast cells, HLMC) by countercurrent elutriation followed by discontinuous Percoll density gradient. SCF contents of human mast cells were assessed for immunoreactive SCF by ELISA. Western blot analysis of SCF and its cleavage products were performed with the MoAb anti-SCF 7H6. SCF and its proteolytic fragment were characterized by electrospray mass spectrometry (ES/MS). RESULTS: SCF is present in the secretory granules of human skin and lung mast cells. Immunoreactive SCF (iSCF) was detected in the cell lysates of HLMC, but not in basophils. iSCF was rapidly (3 min) released after challenge with anti-IgE, and iSCF in supernatants rapidly declined after 30 min. ES/MS analysis of rhSCF1-166 treated with recombinant human chymase showed a polypeptide of 17,977.1+/-0.6 Da and a minor component of 697.4+/-0.1 Da generated by specific cleavage at Phe159. SCF1-166 and SCF1-159 similarly activated HLMC and potentiated anti-IgE-induced activation of these cells. The cleavage product SCF160-166 had no effect on mast cells. Western blot analysis of supernatants of anti-IgE activated HLMC incubated for various intervals with rhSCF1-166 showed that rhSCF1-166 was converted to a faster-migrating form with a molecular weight compatible with SCF1-159 and to several SCF species. CONCLUSION: SCF is stored in human mast cell secretory granules and is immunologically released by mast cells. SCF1-166 is rapidly cleaved by chymase and other proteases to several SCF species.

Autocrine Communication↗
PubMedDate not supplied

Expression of the chemokine receptor CCR3 on human mast cells.

BACKGROUND: The aim of this study was to investigate whether human mast cells express functional active CCR3 receptors, which are activated by CC chemokines. These ligands include the CCR3-selective chemokines eotaxin and eotaxin-2 and the more promiscuous CC chemokines, MCP-4, MCP-3, MCP-2 and RANTES. METHODS: Immunohistochemical analysis was performed on skin, gut and lung specimens. Double immunostaining was performed with anti-CCR3 and antitryptase, and anti-CCR3 and antichymase antibody (Ab) by using the avidin-biotin-peroxidase system with two different substrates. Mast cells were isolated and purified from human lung parenchyma (HLMC) by countercurrent elutriation followed by discontinuous Percoll density gradient. Flow-cytometric analysis of HLMC surface CCR3 expression was performed with the monoclonal Ab anti-CCR3 (7B11). Functional activation of HLMC was verified by the ability of cells to release histamine and/or migrate in response to eotaxin. RESULTS: High percentages (>70%) of tryptase-positive cells showing CCR3 expression were found in the skin and in the intestinal submucosa, whereas much lower percentages (< or = 20%) were found in the intestinal mucosa and in the lung interstitium. Eotaxin (1-100 nM) neither induced histamine release from HLMC nor enhanced anti-IgE-induced histamine release. In contrast, eotaxin (10-100 nM) and RANTES (10-100 nM) induced HLMC chemotaxis in vitro. Preincubation of HLMC with antibody anti-CCR3 (5 microg/ml) before loading into the chemotaxis chamber abrogated chemotaxis elicited by eotaxin. Double immunostaining with anti-CCR3 and anti-chymase antibody showed that the vast majority of CCR3-expressing mast cells in the various human tissues examined were tryptase-chymase double-positive. CONCLUSIONS: These results indicate that CCR3 is expressed on human mast cells and that these cells are attracted by CCR3-binding chemokines.

Cells, Cultured↗
PubMedDate not supplied

Histamine-induced activation of human lung macrophages.

BACKGROUND: Histamine plays a central role in the pathogenesis of allergic and inflammatory diseases by modulating vascular and airway responses. Increasing evidence suggests that histamine also regulates the function of inflammatory and immune cells. Macrophages are primarily involved in inflammatory diseases of the lung. We explored the ability of low concentrations of histamine to induce the release of proinflammatory mediators from human lung macrophages. METHODS: Macrophages purified (> 95%) from lung parenchyma by Percoll density gradients and adherence to polystyrene dishes were incubated (37 degrees C, 2-24 h) with histamine (10(-9)-10(-6) M). At the end of incubation, the release of beta-glucuronidase and IL-6 was determined. RESULTS: Histamine induced a concentration-dependent release of beta-glucuronidase and IL-6 with a maximum release after 2 and 6 h of incubation, respectively. Exocytosis induced by histamine was noncytotoxic and was Ca(2+)- and temperature-dependent. The effect of histamine was inhibited by the H(1) receptor antagonist fexofenadine but not by the H(2) antagonist ranitidine. CONCLUSIONS: These data indicate that histamine is an effective stimulus for exocytosis and cytokine production from human lung macrophages. These effects are inhibited by pharmacological concentrations of fexofenadine. Our results suggest that histamine may contribute to the long-term evolution of lung inflammation and tissue remodelling in allergic diseases by modulating the production of proinflammatory and immunoregulatory mediators by macrophages.

Cells, Cultured↗
PubMedDate not supplied

Human heart mast cells in anaphylaxis and cardiovascular disease.

All sections of human heart tissue demonstrate tryptase- and chymase-containing mast cells (HHMCs) which have for the first time been isolated, partially purified and studied in vitro. HHMCs contain similar histamine levels as lung and skin mast cells, but tryptase levels are lower than in skin and higher than in lung mast cells. Complement C5a causes rapid dose-dependent release of histamine from HHMCs, but they are refractory to substance P and fMLP. Cross-linking IgE receptors on HHMCs leads to arachidonic acid metabolism through both the cyclooxygenase and 5-lipoxygenase pathways. HHMCs and their vasoactive mediators may be involved in anaphylactic/anaphylactoid reactions in humans and in the pathogenesis of some cardiovascular diseases.

Anaphylaxis↗
PubMedDate not supplied

Biochemical functions of a pool of arachidonic acid associated with triglycerides in human inflammatory cells.

The distribution of arachidonic acid (AA) within intracellular lipid pools of inflammatory cells is thought to be an important factor regulating the production of eicosanoids. We have recently identified a pool of AA associated with triglycerides (TGs) in human lung macrophages. This pool is also present in other human inflammatory cells (mast cells, eosinophils, monocytes and platelets) and it contains a percentage of total cellular AA ranging from 10 to 45%. Kinetic studies of AA incorporation have shown that TG are the first acceptor pool for exogenous AA that is subsequently transferred to phospholipid pools. During cell activation, AA is released from phospholipids; however, a large amount of AA is rapidly reincorporated into TGs. The TG pool also supplies AA to the phospholipid pools once these have been depleted during cell activation. These data suggest that TGs are not only a storage site for AA but may also be important as regulators of AA metabolism and eicosanoid biosynthesis in human inflammatory cells.

Arachidonic Acid↗
PubMedDate not supplied

Arachidonic acid remodeling in human inflammatory cells migrating to the lung in vivo.

Recent evidence suggests that arachidonic acid (AA), the precursor of eicosanoids, is stored in various glycerolipid pools with different biochemical specificities. Upon cell activation, AA is rapidly remodeled within these glycerolipid pools. We have explored the changes in AA content and distribution in human neutrophils as they are activated in vivo in the lungs of patients with adult respiratory distress syndrome (ARDS). Neutrophils from bronchoalveolar lavage fluid of ARDS patients contained an amount of total cellular AA four times larger than that of blood (resting) neutrophils and accumulated a larger proportion of AA into a pool associated with triglycerides (TG). These biochemical changes were associated with an increased number of cytoplasmic lipid bodies and with the acquisition of the hypodense phenotype. These data indicate that the accumulation of AA into TG is a marker of cell activation and suggest a central role of the TG pool in AA metabolism in inflammatory cells activated in vivo.

Arachidonic Acid↗
PubMedDate not supplied

Eosinophil granule proteins are selective activators of human heart mast cells.

Eosinophilia in humans is associated with eosinophil infiltration and cardiac localization of eosinophil granule proteins. Eosinophil cationic proteins are responsible for cardiac disease in some patients with eosinophilia. We have investigated the in vitro effect of four eosinophil granule proteins: eosinophil cationic protein (ECP), major basic protein (MBP), eosinophil-derived neurotoxin (EDN) and eosinophil peroxidase (EPO), on mast cells isolated from human cardiac tissue (HHMC). ECP and, to a lesser extent MBP (0.3-3 microM), but not EDN and EPO, stimulated the release of histamine and tryptase from HHMC. This release reaction induced by ECP and MBP was Ca(2+)- and temperature-dependent and was abolished by preincubation with anti-ECP and anti-MBP, respectively. The activation of HHMC by ECP and MBP was abolished by preincubation with 2-deoxy-D-glucose and antimycin A. These data demonstrate that some eosinophil cationic proteins, ECP and MBP, are selective activators of HHMC, thus contributing to the cardiac lesions in patients with eosinophilia.

Blood Proteins↗