Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our study has examined the synthesis of platelet activating factor (PAF; 1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine) and of structurally related molecules by an enriched preparation (greater than 70%) of the human lung mast cell (HLMC) in response to immunologic stimulation. Upon activation with anti-IgE, HLMC incorporated exogenously provided acetate into a phospholipid that migrated with authentic PAF on TLC. The formation of this product in HLMC occurred concomitantly with histamine and leukotriene C4 release. Further analysis of this phospholipid revealed that 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (GPC) and not 1-alkyl-2-acetyl-GPC was the major 1-radyl-2-acetyl-GPC subclass formed during cell activation. The presence of 1-alkyl-2-acetyl-GPC was confirmed by negative ion chemical ionization mass spectrometry. In addition to this product, anti-IgE-stimulated HLMC synthesized relatively small quantities of another 2-acetylated phospholipid migrating on TLC between phosphatidylcholine and phosphatidylinositol. The chromatographic characteristics of this product suggested that it is a subclass of 1-radyl-2-acetyl-sn-glycero-3-phosphoethanolamine. The catabolism of both 1-acyl-2-acetyl-GPC and 1-alkyl-2-acetyl-GPC was next examined to determine if the predominant formation of 1-acyl-2-acetyl-GPC over 1-alkyl-2-acetyl-GPC were metabolized by the HLMC at similar rates. There was, however, a qualitative difference in the metabolic products derived from the two phospholipids. 1-Alkyl-2-acetyl-GPC was rapidly inactivated by removal of the acetate moiety at the sn-2 position followed by rapid reacylation with arachidonate. By contrast, 1-acyl-2-acetyl-GPC was catabolized mainly by removal of the fatty acyl moiety at the sn-1 position. These data demonstrate the natural occurrence of PAF and at least two structurally similar molecules in anti-IgE stimulated HLMC. Furthermore, an analog containing an ester linkage at the sn-1 position, 1-acyl-2-acetyl-GPC, appears to be the major acetylated product synthesized under these conditions.
 ...
PMID:Synthesis of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine by an enriched preparation of the human lung mast cell. 214 Oct 44

Allergic rhinitis is a classic example of a type I immunological reaction. After allergic provocation tests a biphasic reaction is seen in the respiratory tract that is more pronounced in the lower than in the upper respiratory tract due to the physiological changes during the nasal cycle. The early phase of the immediate reaction starts some minutes after allergen provocation. After 5-10 h the nasal symptoms (discharge, blockage, sneezing and itching of the nose) reappear, a phenomenon which is called the "late-phase response" (LPR). The LPR is of great clinical importance in the pathophysiology of perennial allergic rhinitis and phenomena such as nasal priming and nasal hyper-reactivity. The most important effector cell of the early phase of the immediate reaction is the mast cell, whereas basophils, eosinophils and neutrophil granulocytes seem to be more important for the LPR. There is also evidence for morphological and functional heterogeneity of mast cells in man. The role of the chemotactically immigrated eosinophils in allergic reactions has not been clear until now: the eosinophil-derived mediators may enhance or inhibit the allergic reaction. Also the eosinophils show different morphological and functional states (so-called hypo- and hyperdense eosinophils). The symptoms of allergic rhinitis (sneezing, discharge, blockage, itching of the nose) are caused by different mediators, of which the most important is histamine. Other mediators or modulators of the allergic reactions are leucotrienes, prostaglandins, PAF, serotonin, and the kallikrein-kinine and complement systems. In recent years many regulatory peptides have been detected in the human nasal mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Current pathophysiologic aspects of allergic rhinitis. I]. 226 46

The role of mast cells in active and passive anaphylactic shock was examined using the WBB6F1 mouse, a genetically mast cell-deficient strain. Lethal anaphylactic shock occurred at high incidence rates in mice actively sensitized to bovine serum albumin (BSA). The reaction was specific to BSA since the shock could not be elicited by human or guinea pig serum albumin in these animals. Lethal shock could be prevented by CV-3988 but not by cyproheptadine, which suggests that the shock is mediated by PAF but not by histamine and serotonin. Similarly, lethal shock was provoked by homologous antigens in mice which had been passively sensitized with allogeneic anti-benzylpenicilloyl (BPO) IgG1 monoclonal antibody or with allogeneic or xenogeneic anti-BSA antiserum, but not in those sensitized with allogeneic anti-BPO IgE monoclonal antibody. These findings suggest that mast cells are not necessarily required for anaphylactic shock in the mouse.
 ...
PMID:Production of active and passive anaphylactic shock in the WBB6F1 mouse, a mast cell-deficient strain. 237

Intravital microscopy of the hamster cheek pouch was adopted to serve as a model for quantitative studies of microvascular dynamics and parallel measurements of histamine release during immediate-type mast cell-dependent reactions. Topical challenge with specific antigen in the cheek pouch of immunized hamsters caused an acute inflammatory reaction, including leakage of plasma, vasodilation, and accumulation of leukocytes. Several lines of evidence indicated that the response was due to activation of mast cells: 1) an almost identical inflammatory reaction was seen after challenge with the mast cell secretagogue compound 48/80; 2) both antigen and compound 48/80 evoked distinct mast cell degranulatio and histamine release; 3) blockage of histamine 1-receptors reduced the plasma leakage response (but not leukocyte accumulation) to antigen and compound 48/80 in a very similar manner. In addition, fluorescein-labelled antigen bound specifically to mast cells in cheek pouches of immunized animals, suggesting involvement of mast cell-fixed antigen-specific antibodies, possibly immunoglobulin E. It is suggested that vasodilating prostaglandins exert both pro- and anti-inflammatory actions in vivo, and that they modulate acute allergic inflammation by i) inhibition of inflammatory mediator release, most likely unrelated to prostanoid-induced vasodilation, but caused by cAMP elevation in the mediator-secreting cells, and ii) enhancement of the target action of individual inflammatory mediators (i.e. plasma leakage and leukocyte emigration), most likely as a direct consequence of prostaglandin-induced vasodilation. This view is based on the following observations in the hamster cheek pouch: 1) Inhibition of prostaglandin synthesis with two different nonsteroidal anti-inflammatory drugs (NSAIDs) greatly potentiated plasma leakage, leukocyte emigration and histamine release after challenge with antigen or compound 48/80. The enhanced antigen-induced extravasation of plasma and leukocytes was significantly reduced by 5-lipoxygenase inhibitors, but was unaffected by PAF-receptor antagonism. 2) All aspects of NSAID-induced potentiation, including the increased histamine release, were effectively prevented by topically applied prostaglandin E2 (PGE2, 30 nM), which per se caused a five-fold increase in arteriolar blood flow. Moreover, PGE2 as well as prostaglandin I2 (PGI2) in vasodilating concentrations suppressed the antigen-induced plasma leakage also in the absence of NSAID treatment. 3) In contrast to the mast cell-dependent reactions, the inflammatory effects of individual mediators histamine, leukotrienes B4 and C4) were not influenced by NSAID treatment, and were markedly enhanced by both PGE2 and PGI2.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Intravital microscopic studies on acute mast cell-dependent inflammation. 247 89

Effects of zinc in gastric ulcer have been reviewed through investigations carried out on zinc acexamate (ZAC). ZAC is an organic compound that has been shown to possess an experimental antiulcer effect and a wide therapeutic index, making it a useful drug in the treatment of peptic ulcer disease. ZAC protects from ulceration in several experimental models such as pylorus occlusion, reserpine-induced ulcer, necrotizing agents, PAF-induced ulcer and cold-restraint stress. ZAC first reduces the gastric acid output by inhibiting the mast cell degranulation, an action likely to be mediated through a membrane stabilizing action. Secondly, it enhances the mucosal protection factors by increasing mucus secretion, inhibiting the H+ retrodiffusion and improving microcirculation. ZAC is also effective in acetic acid-induced chronic ulcer, restoring the continuity of the damaged mucosa. Several clinical trials have shown the usefulness of ZAC in acute and maintenance treatment of both gastric and duodenal ulcers. Endoscopic studies showed that ZAC reduced the inflammatory processes (gastritis and duodenitis) associated with ulcer healing. This reduction was statistically significant and not observed with other comparative treatments (H2-antagonists). The observed side-effects were minimal and affected less than 2% of treated patients. The pharmacological profile, clinical effectiveness and good tolerance of ZAC suggest this compound as an interesting option in the treatment of peptic disease.
 ...
PMID:Zinc compounds, a new treatment in peptic ulcer. 266 Nov 83

A diagrammatic representation of the interactions between mediators of hypersensitivity and leukocytes in early, late-phase, and ongoing asthma is shown in Figure 1. Early phase or immediate reactions are largely the result of bronchoconstriction consequent to the release of mediators such as histamine, PGD2, LTC4/D4, and PAF. The principal mediator cell (MC) is the mast cell (although other IgE receptor-bearing cells such as the macrophage, eosinophil, and platelet might also be involved in this immediate response). The stimulus for mediator cell activation may be either immunologic (IgE-dependent) or nonimmunologic (i.e., changes in osmolarity as a result of the respiratory water loss associated with exercise-induced asthma). Late-phase reactions appear to be a consequence of infiltration with neutrophils (N), eosinophils (E), and macrophages (M phi). These cells are recruited and activated either by mast cell-associated chemotactic factors [such as LTB4, PAF, the eosinophil chemotactic factor of anaphylaxis (ECF-A), or high-molecular weight neutrophil chemotactic activity (NCA (HMW))] and/or "lymphokines" derived from T-helper cells (TH) which have been stimulated by antigen processed by the antigen-processing cells (APC). These mononuclear cell interactions are under the control of regulatory T cells [T suppressor (TS) cells] and it is speculated that the availability of these subsets may determine the magnitude of the late-phase response. Lymphokines and monokines which selectively activate neutrophils, eosinophils, and monocytes include LIF, EAF, and IFN-gamma, respectively. Macrophage-derived tumor necrosis factor (TNF) also amplifies the inflammatory response by its capacity to enhance eosinophil cytotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Inflammatory cells in bronchial asthma. 270 38

Antigen challenge of ovalbumin (OA)-sensitized guinea pigs results in significant (p less than 0.05) increases in vascular permeability to Evans blue (EB) dye in the airways, esophagus, and bladder. Mean values +/- SEM in ng EB/mg wet weight tissue for unsensitized versus sensitized animals were: trachea, 23.6 +/- 6.6 versus 92.5 +/- 11.1; main bronchi, 31.1 +/- 12.2 versus 153.1 +/- 14.9; "central" intrapulmonary airways (ipa), 34.6 +/- 11.2 versus 101.3 +/- 6.2; and "peripheral" ipa, 26.2 +/- 6.8 versus 93.5 +/- 13.6. We investigated the involvement of several mediators of inflammation in this process. FPL 55712, a sulfidopeptide leukotriene receptor antagonist, caused significant inhibition of leakage in trachea (to 55.1 +/- 9.8) and main bronchi (91.7 +/- 15.8). Blockade of the cyclooxygenase and lipoxygenase pathways with BW 755C, but not of the cyclooxygenase pathway alone with indomethacin, also significantly reduced EB dye extravasation in trachea (55.1 +/- 18.0), main bronchi (71.7 +/- 23.0), and "central" ipa (62.7 +/- 16.4). The histamine antagonists, chlorpheniramine and cimetidine, only inhibited microvascular leakage in main bronchi (94.4 +/- 20.0). PAF-receptor blockade with the ginkgolide mixture BN 52063 had no effect. Nedocromil sodium, a mast cell stabilizer and an inhibitor of inflammatory cell activation, caused significant inhibition throughout the airways: trachea, 50.4 +/- 10.6; main bronchi, 72.0 +/- 15.3; "central" ipa 61.0 +/- 8.6; "peripheral" ipa 41.9 +/- 12.2. Thus, histamine and lipoxygenase products (in particular, leukotrienes), but not PAF, may mediate the antigen-induced increase in vascular permeability to different degrees in differing regions of the respiratory tract in guinea pigs.
 ...
PMID:Inflammatory mediators involved in antigen-induced airway microvascular leakage in guinea pigs. 284 29

Purified alveolar macrophages (AM) obtained by bronchoalveolar lavage of allergic asthmatic patients are stimulated by incubation with anti IgE or the exposure to the related allergen. Confirming the demonstration of a receptor for the Fc fragment of IgE on the surface of macrophages, IgE was characterised on AMs by a rosette-assay, showing an increased percentage of cells forming rosettes with red blood cells coated with anti-IgE or the specific allergen. The IgE-dependent secretion of arachidonic acid metabolites, PAF-acether and chemotactic factors for neutrophils and eosinophils demonstrated in vitro, together with the in vivo demonstration of the activation of AMs by a local provocation test, suggest that besides mast cell, AM do participate in the inflammatory processes of allergic asthma.
 ...
PMID:Alveolar macrophage and its participation in the inflammatory processes of allergic asthma. 293 75

It is now recognized that, in addition to the preformed mast cell granule mediators, newly generated lipid compounds are likely to be exceedingly important in the mediation of allergic asthma and other atopic diseases. That the initiating event in allergic diseases evokes a far more complex set of biochemical events than those that only lead directly to the release of histamine and other preformed mediators, and that the functional efficacies of the leukotrienes, PGD2, and PAF are significant for allergic pathobiology mandate that the latter compounds will necessarily be subject to efforts for future therapeutic intervention in allergic patient populations.
 ...
PMID:Leukotrienes and other lipid mediators of asthma. 298 Oct 59

A diagrammatic representation of the interactions between mediators of hypersensitivity and leucocytes in early-, late-phase, and ongoing asthma is shown in Fig. 1. Early-phase or immediate reactions are largely the result of bronchoconstriction consequent to the release of mediators such as histamine, PGD2, LTC4/D4 and PAF. The principal mediator cell (MC) is the mast cell (although other IgE receptor-bearing cells such as the macrophage, eosinophil and platelet might also be involved in this immediate response). The stimulus for mediator cell activation may be either immunologic (IgE-dependent) or non-immunologic (i.e. changes in osmolarity as a result of the respiratory water loss associated with exercise-induced asthma). Late-phase reactions appear to be a consequence of infiltration with neutrophils (N), eosinophils (E) and macrophages (MO). These cells are recruited and activated either by mast cell-associated chemotactic factors [such as LTB4, PAF, the eosinophil chemotactic factor of anaphylaxis (ECF-A) or high molecular weight neutrophil chemotactic activity (NCA (HMW]] and/or "lymphokines" derived from T helper cells (TH) which have been stimulated by antigen processed by the antigen processing cells (APC). These mononuclear cell interactions are under the control of regulatory T cells [T suppressor (TS) cells] and it is speculated that the availability of these subsets may determine the magnitude of the late-phase response. Lymphokines and monokines which selectively activate neutrophils, eosinophils and monocytes include LIF, EAF and INF-gamma respectively. Macrophage-derived tumour necrosis factor (TNF) also amplifies the inflammatory response by its capacity to enhance eosinophil cytotoxicity. Eosinophil-derived agents such as PAF, LTC4, MBP and ECP might be responsible for submucosal oedema and non-specific bronchial hyperreactivity which are characteristic features of late-phase reactions. T cell-derived lymphokines such as EDF (IL-5), together with GM-CSF, might lead to eosinophilopoiesis and account for the prolonged eosinophilia of ongoing chronic asthma. The T cell is prominent in the pathology of chronic asthma and is possibly "chronically activated". Thus lymphocytes, driven by as yet undetermined "antigens" (possibly viral), may perpetuate the inflammatory response in and around the bronchi. IL-5-like products from these putative activated lymphocytes might perpetuate (a) eosinophil production by the bone marrow, (b) its release into the circulation, (c) its migration into bronchial tissue and (d) activation to release PAF, LTC4, MBP, etc.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Leucocytes in asthma. 306 26


<< Previous 1 2 3 4 5 Next >>