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  • 1
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Macrophages are involved in immediate hypersensitivity reactions by their ability to release leukotrienes involved in the symptomatology of allergy. To date it is unknown whether this ability to secrete leukotrienes has been favoured by modifications, occurring during the sensitization phase, of the enzymes involved in leukotriene metabolism.Objective We used ovalbumin-sensitized rats to study the expression of cytosolic phospholipase A2 (cPLA2), 5-lipoxygenase (5-LO) and 5-lipoxygenase-activating protein (FLAP) in peritoneal macrophages during active sensitization. We compared basal and challenged (PMA, A23187 and allergen) arachidonic acid (AA) metabolism of macrophages from control (cPM) and sensitized (sPM) rats. Then we tested, in cultured cPM, whether IL-4, the predominant cytokine of sensitization process, could reproduce the enzymatic modifications occurring in macrophages during sensitization.Methods cPLA2, 5-LO and FLAP expression was assessed by Western blotting. The arachidonic acid (AA) metabolism study was performed after incorporation of tritiated AA in macrophages and analysis of secreted tritiated eicosanoids.Results Ovalbumin-sensitization of rats increased cPLA2, 5-LO and FLAP expression in peritoneal macrophages. These increased expressions were not paralleled by modifications of basal and PMA- or A23187-stimulated AA metabolism of sPM. However, when macrophages encountered the specific allergen for a second time, sPM secreted higher levels of leukotrienes than cPM. IL-4 induced FLAP expression in cPM but had no effect on cPLA2 and 5-LO expression.Conclusion Active sensitization of rats induces an increase, in peritoneal macrophages, of the enzymes involved in leukotriene metabolism. The increased leukotriene secretion of sPM in response to ovalbumin challenge may be favoured by this increased expression of cPLA2, 5-LO and FLAP that, however, is not able to lead to modifications of macrophage AA metabolism in any circumstance. Our results also suggest that IL-4 is not the major element originating the enzymatic modification induced by sensitization in peritoneal macrophages.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 50 (1995), S. 0 
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The tachykinin substance P (SP) is present in lung sensory nerve endings and may be released after neurogenic stimulation. Its role in the pathogenesis of asthma is still unclear. Nevertheless, it may play a major role in airway neurogenic inflammation. Alveolar macrophages are the predominant cells of the airway space and are involved in various types of airway inflammation. We studied guinea pig alveolar macrophage response to SP and other related peptide (C- and N-terminal sequences, NK1-receptor agonist) stimulation. Alveolar guinea pig macrophages were recovered by bronchoalveolar lavage (BAL). Macrophage reactive oxygen intermediate (ROI) production was studied by luminol-dependent chemiluminescence with several concentrations of SP and related peptides. Eicosanoid synthesis after stimulation was evaluated by thin-layer chromatography (TLC) and enzyme-linked immunosorbent assay (ELISA). SP, C-terminal sequence, and NKl-receptor agonist significantly increased ROI production by alveolar macrophages (P〈0.01). NK1 -agonist and C-terminal sequence modified arachidonic acid metabolism and induced a significant increase in prostaglandin (PG)D2 synthesis (211% and 66%, respectively). We concluded that SP and related peptides directly affect guinea pig alveolar macrophages by inducing the production of inflammatory metabolites.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism 1167 (1993), S. 165-174 
    ISSN: 0005-2760
    Keywords: (Rat) ; Allergen challenge ; Icosanoid ; Membrane phospholipid ; Passive sensitization ; Peritoneal macrophage
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism 834 (1985), S. 8-22 
    ISSN: 0005-2760
    Keywords: (Mouse peritoneal macrophage) ; Arachidonic acid conversion ; Chloramphenicol ; Glycerolipid ; Prostaglandin synthesis
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism 1213 (1994), S. 46-56 
    ISSN: 0005-2760
    Keywords: (Guinea-pig) ; Active sensitization ; Allergen challenge ; Alveolar macrophage ; Icosanoid ; Membrane phospholipid ; Serum
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 147 (1997), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: There is evidence that exopolysaccharides (EPS) contribute to the persistence of Pseudomonas aeruginosa in cystic fibrosis lung. However, the relationship between the chemical composition of EPS and the modulation of phagocytic cells is poorly understood. In order to evaluate the role of the chemical composition of EPS in macrophage behavior changes, we pretreated macrophages with characterized EPS and assessed P. aeruginosa phagocytosis and reactive oxygen intermediate (ROI) production. The results showed that alginate and neutral polysaccharides are involved in phagocytic impairment of P. aeruginosa. Moreover, alginates were able to prime macrophages for increased P. aeruginosa-induced macrophage oxidative burst as determined by chemiluminescence. In contrast, neutral polysaccharides are responsible for the decrease of ROI by a scavenging effect evaluated by the xanthine–xanthine oxidase system. This study showed that the content of P. aeruginosa EPS in alginate, but also in neutral polysaccharides, influences the behavior of strains towards phagocytosis and macrophage oxidative burst.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 34 (1978), S. 87-88 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of 4 carbaryl doses (0.375, 0.75, 1.50 and 3 mg/100 g) on the reticuloendothelial system (RES) phagocytic activity were studied 1 h after their administration to male rats. Carbaryl reduced RES phagocytic activity. Results showed a dose-dependent drop in RES phagocytic activity. Carbaryl might act as an inhibitor of phagocytes by saturing them to greater or lesser degree, depending on the dose administered.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. The changes in metabolism and cytotoxicity of chlorpropham (CIPC) and its major metabolites, 4-hydroxychlorpropham (4-OH CIPC), 3-chloroaniline, and 3-chloroacetanilide were investigated in isolated rat hepatocyte suspensions after a partial inhibition of sulphation and glucuronidation and the two reactions combined in an attempt to assess the part of each of them in the enhanced CIPC toxicity observed in vivo after D-galactosamine treatment. With sulphation and glucuronidation effective, CIPC has a cytolytic effect and reduces intracellular ATP and K+ level while 4-OH CIPC has a weak cytolytic effect but modifies ATP and K+ level in a greater extent than CIPC. Inhibition of sulphation does not affect the cytotoxicity of CIPC or 4-OH CIPC because there is a compensatory increase in the amount of 4-OH CIPC glucuronide formed and the level of free 4-OH CIPC always remain low. In contrast, when incubations are carried out with either CIPC or 4-OH CIPC, the presence of D-galactosamine leads to a decrease of glucuronide and sulphate conjugates accompanied, respectively, by a 3.6-fold and 6.9-fold increase of the free 4-OH CIPC level in the culture medium. This alteration of the metabolism is followed by a marked reduction of ATP synthesis with a concomitant modification of cell permeability. The cytolytic effect is due to CIPC itself, whereas the effect on energy supply was attributed to free 4-OH CIPC. The results demonstrate a combined effect of free 4-OH CIPC and D-galactosamine on intracellular ATP level that could account for the partial inhibition of sulphation. This change in the CIPC metabolism could explain the increased CIPC toxicity observed in vivo after D-galactosamine pretreatment.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1420-908X
    Keywords: Key words: Kupffer cells – Prostaglandins – Leukotrienes, Reactive oxygen intermediates – Liver injury
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Objective and Design: The aim of the present study was to characterize during acute and chronic liver injury induced by CCl4, macrophage phenotypes and whether a change in reactive oxygen intermediates (ROI) and eicosanoids production by Kupffer cells (KC) was observed.¶Material and Methods: Liver steato-necrosis and cirrhosis were induced in rats after 3 weeks and 9 weeks of CCl4 intoxication, respectively. Monocytes and tissue macrophages were identified by immunohistochemical study using monoclonal antibodies ED-1 and tissue macrophages using the antibody ED-2. The release of ROI and eicosanoids in response to the phorbol ester TPA (protein kinase activator) and to the calcium ionophore A23187 was assessed in cultivated cells.¶Results: As compared to healthy controls, livers of rats with steato-necrosis or cirrhosis exhibited a significant increase of ED-1 and ED-2 positive cells. Only KC from rats with liver steato-necrosis were found to have higher A23187, TPA + A23187 or opsonized zymosan induced ROI production than healthy controls (p〈0.01). After TPA + A23187 or opsonized zymosan stimulation, KC from both rats with steato-necrosis or cirrhosis produced more TxB2 and leukotrienes and less PGE2 as compared to healthy controls (p〈0.05).¶Conclusions: These results suggest an influx of monocytes into the liver during acute and chronic injury induced by CCl4. Functional changes of this inflammatory infiltrate have been demonstrated with an increase of ROI production only in the early stage of liver injury whereas a rise in KC leukotriene production and an imbalance between cytoprotective and cytotoxic prostanoids were observed at all stages of liver disease.
    Type of Medium: Electronic Resource
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