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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ascaris suum antigen effects on mean airflow resistance (RL) and bronchial arterial blood flow (Qbr) were studied in allergic anesthetized sheep with documented airway responses. Qbr was measured with electromagnetic flow probes, and supplemental O2 prevented antigen-induced hypoxemia. Aerosol challenge with this specific antigen increased RL and Qbr significantly. Cromolyn sodium aerosol pretreatment prevented antigen-induced increases in RL but not in Qbr. Intravenous cromolyn, however, prevented increases in Qbr and RL, suggesting a role for mast cell degranulation in both bronchomotor and bronchovascular responses to antigen. Antigen-induced increases in Qbr were not solely attributable to histamine release. Indomethacin pretreatment attenuated the antigen-induced increase in Qbr, thus suggesting that vasodilator cyclooxygenase products contribute to the vascular response. Antigen challenge significantly decreased Qbr after indomethacin and metiamide pretreatment, which suggests that vasoconstrictor substances released after antigen exposure also modulate Qbr; however, released vasodilators overshadow vasoconstrictor effects. Thus antigen challenge affects Qbr by locally releasing histamine and vasodilator prostaglandins as well as vasoconstrictor substances. These effects were independent of antigen-induced changes in systemic and pulmonary hemodynamics.
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PMID:Modification of bronchial blood flow during allergic airway responses. 313 32

PGD2 undergoes extensive isomerization in vivo followed by metabolism by 11-ketoreductase to yield a family of biologically active isomeric PGF2 compounds, including 9, alpha 11 beta-PGF2. Because immunologically activated human mast cells produce substantial quantities of PGD2 and eosinophils accumulate around mast cells at sites of immediate hypersensitivity reactions, the ability of eosinophils to metabolize PGD2 was investigated. Purified human circulating eosinophils from four different donors transformed PGD2 to 9, alpha 11 beta-PGF2 and 12-epi-9 alpha, 11 beta-PGF2 in a time- and concentration-dependent manner. The formation of these compounds increased rapidly during the first 30 min of incubation of eosinophils with PGD2 and tended to plateau at approximately 2 h. Detection and quantification of the formation of 9 beta,11 beta-PGF2 and its 12-epi isomer was accomplished by a negative ion chemical ionization gas chromatography/mass spectrometry assay. On one occasion, eosinophils from one donor also transformed PGD2 to two additional isomeric PGF2 compounds, the stereochemical structures of which were not identified. The ability of eosinophils to produce PGD2 was then investigated. After stimulation with 2 microM A23187, the major cyclooxygenase product formed was thromboxane B2 (2247 pg/10(6) eosinophils) whereas only small quantities of PGD2 were produced (50 pg/10(6) eosinophils). Inasmuch as PGF2 compounds can exert biologic actions that differ from those of PGD2, this ability of eosinophils to transform PGD2 to PGF2 compounds could alter the local biologic effects of PGD2 released from adjacent mast cells and thus may represent a physiologically relevant mast cell-eosinophil interaction.
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PMID:Transformation of prostaglandin D2 to isomeric prostaglandin F2 compounds by human eosinophils. A potential mast cell-eosinophil interaction. 313 58

Bronchial asthma is a multifactorial disease characterized by reversible bronchoconstriction, airway hyperreactivity, oedema and excessive mucus production. Present therapy directed against specific mediators has not been overwhelmingly successful. Even though there exists a multiplicity of purported mediators, perhaps the key to better therapy is a vigorous understanding of the arachidonic acid cascade and investigations to modulate specific products of these pathways. Within the cyclooxygenase pathway an interesting scenario might be to effectively antagonize the potent bronchoconstrictive effects of prostaglandin (PG)D2 and its recently identified predominant metabolite, an 11-hydroxyl epimer, 9 alpha,11 beta-PGF2. PGD2 is the major cyclooxygenase product released from sensitized human lung and bronchoalveolar lavage (BAL) mast cells; it possesses a myriad of biological actions relevant to the pathogenesis of asthma. While no specific antagonists of PGD2 or 9 alpha,11 beta-PGF2 have been identified, some preliminary studies have suggested that, perhaps, PGD2 may be interacting, at least in part, with thromboxane receptors. In addition, peroxidation of arachidonic acid catalyzed by 5-lipoxygenase produces the leukotrienes, which are extremely potent bronchoconstrictors as well as oedema and mucus secretagogues. Leukotrienes are primary mast cell mediators which may be the vital link to both early (acute) and late (chronic) asthmatic attacks. Research seeking leukotriene antagonists has been intensive. Leading clinical candidates have emerged from Smith Kline and French, Lilly, Merck-Frosst, ICI-Stuart and other groups. However, we must await the outcome of ongoing clinical trials in asthmatics to determine just how important the leukotrienes really are in the pathogenesis of asthma, allergy and inflammation. Thus, modulation of the effects of products of arachidonic acid metabolism may provide a new and more specific treatment for bronchial asthma.
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PMID:Modulation of arachidonic acid metabolites as potential therapy of asthma. 314 Jun 17

Characteristics of the antigen-induced contraction of the isolated esophageal muscularis mucosae of actively sensitized guinea-pigs to ovalbumin (OA) were examined in vitro, and they were compared with those of compound 48/80- or polymyxin B-induced contraction. OA, above 0.01 microgram/ml, produced a sustained contraction of the sensitized esophageal muscularis mucosae, the amplitude of which was about 80-100% of the maximum contraction induced by carbachol (10 microM), while compound 48/80 and polymyxin B (10-300 micrograms/ml) produced less potent contractions of the non-sensitized esophageal muscularis mucosae. Contractions to OA or compound 48/80, but not to polymyxin B, were diminished by their repetitive applications. The contractile responses to OA, compound 48/80 and polymyxin B depended on the external calcium concentrations, and were abolished in the calcium-free medium. Pretreatment with tetrodotoxin (0.3 microM), atropine (0.3 microM), diphenhydramine (30 microM) or DSCG (300 microM) did not modify any of these contractions, whereas BW755C (100 microM) and quercetin (10 microM) significantly inhibited them. Indomethacin (10 microM) largely prevented only the polymyxin B-induced contraction, while FPL55712 (10 microM) inhibited both contractions to OA and compound 48/80. These findings indicate that the OA-induced anaphylactic contraction of the esophageal muscularis mucosae taken from the OA-sensitized guinea-pig may be an indirect action via the stimulation of releases of some mast cell-derived spasmogens. The spasmogens may involve the lipoxygenase products of arachidonic acid in part, but not histamine, acetylcholine or the cyclooxygenase products.
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PMID:[Pharmacological characterizations of the in vitro anaphylactic contraction of the guinea-pig esophageal muscularis mucosae]. 337 90

To investigate the pathogenesis of allergic rhinitis, we developed a nasal challenge model in which we examined the early, late, and rechallenge responses to antigen provocation. In these three aspects of the allergic reaction the physiologic responses are associated with inflammatory mediator release. Whereas the early response appears to be related mainly to mast cell activation and mediator release, the late reaction involves a different pattern of mediator release and an inflammatory cell influx, consisting of basophils, neutrophils, and eosinophils. Rechallenge with antigen 11 hours later results in an augmented immediate response. Pretreatment with aspirin reduces the levels of cyclooxygenase metabolites in nasal secretions without affecting the immediate physiologic response to antigen or the expected increase in the levels of histamine, N-alpha-tosyl-L-arginine methyl ester-esterase activity, and leukotriene C4. Pretreatment with systemic steroids does not affect the early allergic response, but significantly reduces mediator release during the late and rechallenge responses. The influx of eosinophils is inhibited by pretreatment with systemic steroids, but neutrophil influx is not. In contrast, pretreatment with topical steroids blocks the early response and the late and rechallenge responses. Influx of all cell types, including the neutrophil, was prevented. These studies show unequivocally that an inflammatory process follows the initial response to antigen and that this inflammation is affected by drugs important in the treatment of chronic allergic disease. We speculate that understanding allergic inflammation will lead to new therapeutic development.
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PMID:Experimentally induced nasal allergic responses. 337 15

Insight into the pathogenesis of human allergic and inflammatory disorders has been obtained through a combination of in vitro and in vivo studies. These investigations have demonstrated that human basophils and mast cells release mediators after nonimmunologic as well as immunologic activation in vitro and in vivo: nonimmunologic triggers include changes in osmolarity. Although these cells share many properties, including the presence of high-affinity receptors for IgE on their cell surface, the presence of histamine in granules, the ability to generate and release large quantities of leukotriene C4 (LTC4) after activation, and the ability of several pharmacologic agents including phospholipase inhibitors, acetylene analogues of arachidonic acid (ETYA, ETI), methylxanthines, prostaglandin E2 (PGE2) beta-agonists, and cyclic AMP to inhibit mediator release, they also display notable differences. Human lung mast cells generate and release large quantities of prostaglandin D2 (PGD2) after activation; basophils generate no known cyclooxygenase product. Indomethacin, arachidonic acid, and 5-hydroperoxyeicosatetraenoic acid (5-HPETE) all enhance histamine and LTC4 release from human basophils; no effect is seen with human lung mast cells. Overnight incubation of basophils with glucocorticoids produces a marked inhibition of mediator release; this treatment does not affect the release of mast cell mediators. These in vitro observations are consistent with our in vivo observations and our hypotheses concerning the importance of these cells in allergic disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The pharmacologic control of mediator release from human basophils and mast cells. 349 82

The immediate and late asthmatic reactions provoked by inhaled allergens have provided useful models enabling the dissection of individual inflammatory cells and their mediators that may contribute to the pathogenesis of asthma. The immediate reaction is considered to be mast cell-mediated on the basis that about 50% of the response is inhibitable by potent and selective H1-receptor antagonists such as terfenadine and astemizole. Additional inhibition (approximately 30%) by the potent cyclooxygenase inhibitor flurbiprofen implies an important role for prostanoids in the immediate response, the most likely mast cell-derived product being prostaglandin (PG) D2. In man, PGD2 is selectively metabolised to 9 alpha 11 beta-PGF2, a unique prostaglandin which shares with PGD2 contractile properties on guinea-pig and human airways smooth muscle. The inability of piriprost, a potent leukotriene synthesis inhibitor, to influence the allergen-provoked immediate reaction raises the possibility that sulphidopeptide leukotrienes play a minor role in this response. The late asthmatic reaction is considered to resemble clinical asthma since it is accompanied by increased responsiveness of the airways to a wide range of stimuli. The late reaction in man is inhibited by nedocromil sodium (4 mg) but only marginally attenuated by salbutamol (200 micrograms) if both drugs are administered prior to allergen challenge. Since salbutamol, in the dose administered, is a potent mast cell-stabilising agent, these findings must question the obligatory role of mast cell mediator release in the pathogenesis of the late response.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Primary and secondary effector cells in the pathogenesis of bronchial asthma. 355 30

Mast cells produce a variety of enzymes and vasoactive, chemotactic, and bronchoconstrictor substances in response to nonimmunologic as well as immunologic stimuli. These mast cell-derived mediators may act on airway smooth muscle, submucosal glands, epithelial cells, circulating blood cells, vascular cells, and other cell types. The secretory profile of a mast cell appears to depend on the specific stimulus applied. In addition, different populations of mast cells exist, and distinct enzymatic pathways may predominate in different cell types. The effect of mast cell-derived mediators on the various target cells may be direct or indirect. For example, mediators released by immunologic challenge of sensitized lung fragments or by nonimmunologic challenge of canine mastocytoma cells stimulate the transport of ions and water across the tracheal epithelium. This effect, however, is indirect, is blocked by indomethacin, and therefore appears to be dependent upon an intact cyclooxygenase pathway in the tracheal epithelium. Canine mastocytoma cells resemble normal mast cells in dog lung and skin, and can be propagated to provide a continuous source of large numbers of pure, identical mast cells for biochemical and physiologic studies. Studies of these cells and their inflammatory mediators will increase our understanding of the complex series of cell-to-cell interactions which are responsible for the pathophysiologic manifestations of obstructive lung disease.
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PMID:Mast cell-derived mediators and their role in cell-to-cell interactions in the lung. 356 13

Prostaglandins and related compounds comprise an ubiquitous biological system which utilizes arachidonic acid (5,8,11,14-eicosatetraenoic acid) as a common cellular precursor to synthesize a great number of substances with a broad range of activities, including participation in the cellular and humoral events of inflammation and allergy. Briefly, prostaglandins and thromboxanes (TX) are formed in reactions initiated by the aspirin-sensitive fatty acid cyclooxygenase, whereas leukotrienes (LT) and several other compounds are generated by different lipoxygenases present in human tissues. In the field of asthma, the mast cell-derived PGD2 alpha, as well as PGF2 alpha and TXA2 are known as reasonably potent bronchoconstrictors, and asthmatics are remarkably hyperreactive to inhalation of PGF2 alpha. However, the therapeutic failure of aspirin and related cyclooxygenase inhibitors in the treatment of asthma suggests that these compounds are less likely to be primary mediators. On the other hand, several lines of evidence indicate that three closely related leukotrienes, LTC4, LTD4 and LTE4, previously known as slow-reacting substance of anaphylaxis (SRS-A), have the potential to be major mediators of the airway perturbations characteristic of bronchial asthma. Thus, as documented both in experimental animals and in man, these leukotrienes are exquisitely potent in causing bronchial smooth muscle contraction, mucosal edema, and secretion of mucus into the lumen. In particular, LTC4, LTD4 and LTE4 have been linked to allergic asthma because allergen challenge is a potent stimulus for their release from, e.g., lung tissue of asthmatics. In fact, it has been documented that inhibition of leukotriene formation can block allergen-induced contractions of isolated human bronchi.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Leukotrienes and other eicosanoids as mediators of airway obstruction. 356 14

1-0-Alkyl-2-Acetyl-sn-Glycero-3-Phosphocholine (AGEPC) produced dose-dependent (75-500 ng/site) increases in cutaneous vascular permeability (CVP) in rats as measured by extravasation of Evans blue dye. In contrast, lyso-AGEPC, at 1000 ng/site, was without effect. Pyrilamine, methysergide, and phenoxybenzamine, antagonists of mast-cell derived mediators, did not affect the AGEPC-induced increase in CVP. Likewise, agents capable of inhibiting mast cell mediator release, such as disodium cromoglycate, PRD-92-EA, theophylline, or nifedipine, had no effect. The cyclooxygenase inhibitor indomethacin produced significant inhibition of the response to AGEPC, whereas the lipoxygenase inhibitor nordihydroguiaretic acid (NDGA) and the peptide leukotriene antagonist FPL 55712 were without effect. The response to AGEPC was enhanced by the vasodilator PGE2 and inhibited by the vasoconstrictor phenylephrine. The selective AGEPC antagonist CV-3988 provided marked inhibition of the response. Unaccountably, the combination of indomethacin and CV-3988 provided no greater inhibition of the responses than either agent alone. These observations indicate that the AGEPC-induced increase in CVP in rats is mediated in part by products of the cyclooxygenase pathway and in part by activation of an AGEPC receptor.
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PMID:Pharmacologic analysis of 1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine-induced increases in cutaneous vascular permeability in the rat. 357 57


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