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

As part of an ongoing investigation of human mast cell heterogeneity, we have isolated, partially purified, and characterized the uterine mast cell and compared it with mast cells isolated from other organs. The average histamine content of myometrium and leiomyofibroma obtained from hysterectomies was 2.1 +/- 0.3 (mean +/- SEM) microgram/g of tissue (n = 10), and the histamine content of the two tissues did not differ significantly. A mild collagenase, hyaluronidase, and DNase digestion was used to disperse the uterine mast cells, with an average yield of 9.5% (range, 0 to 21%). The average histamine/uterine mast cell was 2.1 +/- 0.2 pg (n = 3), and 61 +/- 7% (n= 3) of the uterine mast cells survived overnight culture. Early purification efforts with Percoll gradients have yielded up to 80% pure uterine mast cells, with an average of 27 +/- 10% (n = 5). Uterine mast cells released histamine in response to the secretogogues anti-IgE and A23187 but did not respond to substance P or to the basophil secretogogues FMLP, C5a, and 12-O-tetradecanoylphorbol-13-acetate. After 1 microgram/ml anti-IgE stimulation, the uterine mast cell appeared to make significant quantities of PGD2 (89 +/- 26 ng/10(6) cells, n = 6) (p less than 0.05), as assayed by RIA. Simultaneously, leukotriene C4 release was 45 +/- 15 ng/10(6) cells, (n = 6) (p less than 0.05), as assayed by RIA. Combined gas-chromatography mass spectroscopy analysis of anti-IgE-stimulated cell supernatants confirmed the production of PGD2. In pharmacologic studies, isobutyl-methylxanthine and isoproterenol blocked anti-IgE-induced histamine release. The uterine mast cell is similar to the lung mast cell in terms of response to secretogogues and release of arachidonic acid metabolites. Ultrastructurally, the uterine mast cell contains scroll granules, crystal granules, combined granules, homogeneously dense granules, and large lipid bodies, many with focal lucencies within them. Particle granules, most frequently present in gut mast cells of mucosal origin, were absent from uterine mast cells. Although certain features are analogous to the ultrastructure of skin or lung mast cells, the combination of structures is distinctive for uterine mast cells.
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PMID:Human uterine mast cells. Isolation, purification, characterization, ultrastructure, and pharmacology. 171 65

The bronchus was isolated from actively sensitized guinea pigs, and the effect of antigen challenge on the excitability of bronchial parasympathetic ganglion neurons was examined with standard intracellular recording techniques. Based on histological examination, we found that mast cells were located near parasympathetic ganglia neurons. Antigen challenge resulted in a loss of mast cell staining and the release of the mast cell-associated mediators, histamine (38 ng/g, approximately 14% of total content) and prostaglandin D2 (PGD2, 118 ng/g wet weight of tissue). Challenging the isolated bronchus with the sensitizing antigen resulted in a transient depolarization (mean 6 mV) of the resting membrane potential of the neurons. Antigen challenge also had a dramatic effect on the accommodative properties of the neurons. Before antigen challenge, two subpopulations of neurons could be differentiated by their response to cathodal current steps: 60% of the cells responded in a "phasic" manner, firing one to six spikes and then accommodated, whereas the balance fired spikes repetitively throughout the current pulse. In phasic firing cells, ovalbumin challenge produced a decrease in accommodation. This was evidenced by a fivefold increase in the number of action potentials elicited during a 500-ms suprathreshold current pulse. The antigen-induced depolarization could be mimicked by histamine, whereas the decrease in accommodation was mimicked by application of PGD2. Leukotriene C4, another mast cell-associated mediator, had no effect on these neuronal properties. These results provide evidence that the immediate hypersensitivity response in guinea pig airways may involve changes in membrane characteristics of bronchial parasympathetic ganglia neurons.
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PMID:Influence of antigen on membrane properties of guinea pig bronchial ganglion neurons. 172 6

Intravascular application of goat anti-rabbit immunoglobulin E (IgE) was used to stimulate parenchymal mast cells in situ in perfused rabbit lungs. Sustained pulmonary arterial pressure rise was evoked in the absence of lung vascular permeability increase and lung edema formation. Early prostaglandin (PG) D2 and histamine release into the perfusate was documented, accompanied by more sustained liberation of cysteinyl leukotrienes (LT), LTB4, and PGI2. The quantities of these inflammatory mediators displayed the following order: histamine greater than cysteinyl-LT greater than PGI2 greater than LTB4 greater than PGD2. Pressor response and inflammatory mediator release revealed corresponding bell-shaped dose dependencies. Cyclooxygenase inhibition (acetylsalicylic acid) suppressed prostanoid generation, increased LT release, and did not substantially affect pressor response and histamine liberation. BW755 C, a cyclo- and lipoxygenase inhibitor, blocked the release of cysteinyl-LT and markedly reduced the liberation of the other inflammatory mediators as well as the pressor response. The H1-antagonist clemastine caused a moderate reduction of the anti-IgE-provoked pressure rise. We conclude that intravascular anti-IgE challenge in intact lungs provokes the release of an inflammatory mediator profile compatible with in situ lung parenchymal mast cell activation. Pulmonary hypertension represents the predominant vascular response, presumably mediated by cysteinyl-LT and, to a minor extent, histamine liberation.
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PMID:Intravascular anti-IgE challenge in perfused lungs: mediator release and vascular pressor response. 172 6

In asthmatics, both the continuous release of mast cell-derived inflammatory mediators and damage of the airway epithelium may be related to the degree of bronchial responsiveness. We therefore evaluated the effect of inflammatory mediators and mast cell activation on the cholinergic responsiveness of strips of human bronchioles with and without epithelium. Cumulative concentration-response curves to methacholine were generated from strips with or without epithelium before, during and after incubation with threshold doses of either methacholine (3 x 10(-7) M, controls), histamine (3 x 10(-7) M), the thromboxane A2 analogue, U46619 (10(-9) M), prostaglandin (PG) D2 (3 x 10(-7) M), PGF2 alpha (3 x 10(-7) M), leukotriene (LT) C4 (10(-9) M), or anti-human immunoglobulin E (24.4 +/- 4.0 micrograms.ml-1). Strips without epithelium were 1.6 times more sensitive to methacholine than strips with epithelium (-log EC50:5.76 +/- 0.04 vs. 5.97 +/- 0.04, P less than 0.0001). The average contraction in response to identical doses of anti-IgE in strips without epithelium was 3 times greater than the contraction in strips with epithelium (P less than 0.05). Threshold concentrations of histamine, U44619 and PGD2 caused a similar non-parallel leftward shift of the concentration-response curve of strips with or without epithelium to methacholine (P less than 0.05). Together, epithelial denudation and low levels of mediators caused a 4.0- to 9.1-fold increase in sensitivity based on the -log EC10 and a 1.8- to 3.0-fold increase in sensitivity based on the -log EC50.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of epithelial denudation, inflammatory mediators and mast cell activation on the sensitivity of isolated human airways to methacholine. 180 Jan 16

Recent evidence suggests that neural transmitters, including neuropeptides, may modulate the release of mast cell mediators. Because neuropeptide Y (NPY) has recently been recognized as a putative cotransmitter in noradrenergic neurons, we studied the effect of NPY on purified rat peritoneal mast cells. NPY induced mast cell degranulation, as assessed by a dose-dependent increase in net release of beta-hexosaminidase. The concentration that produced 50% of the maximal effect, approximately 10 mumol/L, evoked a 40% +/- 3% release. As previously reported for other neuropeptides, release was fast with maximal release already achieved at 60 seconds. Release was at 4 degrees C. In contrast to its effects on mast cell degranulation, NPY had no effect on the generation of prostaglandin D2, the major mast cell cyclooxygenase product. By comparison, the calcium ionophore A23187, at doses (4 mumol/L) that evoked comparable release of beta-hexosaminidase, stimulated a net release of 37 +/- 9 ng of PGD2 per 10(6) mast cells. These results raise the possibility that NPY may act as a modulator between the autonomic nervous system and mast cells. The results also imply that with neuropeptide stimulation, the release of preformed and newly formed mast cell mediators are mediated through independent pathways.
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PMID:Neuropeptide Y, a putative cotransmitter in noradrenergic neurons, induces mast cell degranulation but not prostaglandin D2 release. 182 2

Previous work suggests a role for mast cell derived mediators in exercise induced asthma. The contribution of newly generated contractile prostaglandins to exercise induced asthma was assessed by using a potent and orally active thromboxane (TP1) receptor antagonist, GR32191. The effect of 120 mg GR32191 on exercise induced asthma was observed in 12 asthmatic subjects. For the exercise challenge the subjects performed six minutes of treadmill exercise, breathing dry air at a work load that had previously been shown to induce a fall in FEV1 of 25% or more from the pre-exercise baseline. No effect of GR32191 on pre-exercise baseline airway calibre was evident. There was no significant difference in the mean maximum percentage fall in FEV1 from baseline after exercise between drug and placebo (placebo 30.2%, GR32191 day 31.6%). It is concluded that the thromboxane antagonist GR32191 has no effect on exercise induced asthma. This suggests that prostaglandins, including PGD2, that act via the thromboxane receptor do not have an important role in exercise induced asthma.
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PMID:Effect of GR32191, a potent thromboxane receptor antagonist, on exercise induced bronchoconstriction in asthma. 182 43

The present study investigates the contribution of gastric mast cells on PGD2 generation in rat gastric mucosa. Cold-restraint induced stress or i.v. carbachol injection methods were used for gastric mast cell degranulation. In 19 stressed, 15 carbachol-infused and 14 control rats, gastric mast cell counts and gastric mucosa PGD2 assay were performed. Gastric mucosal content of PGF2 alpha was also determined in carbachol infused and control rats. The mean number of gastric mast cells was significantly lower in stressed and carbachol infused than in control rats. Despite these differences in gastric mast cell counts, neither PGD2 or PGF2 alpha contents in the gastric mucosa were significantly different in mast cells degranulated rats than in control animals. These results suggest another source of PGD2 in the rat gastric mucosa other than mast cells.
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PMID:Mast cells in the rat gastric mucosa are not primarily responsible for PGD2 generation. 187 77

This study has examined the metabolism of arachidonic acid in the mouse bone marrow-derived mast cell (BMMC) during immunologic and nonimmunologic activation. The predominant pools of endogenous arachidonate in the mast cells were found in ethanolamine (46%), choline (39%) and inositol (14%) containing glycerolipids. Initial studies established conditions where equilibrium labelling of these major phospholipids in the BMMC could be reached. Upon challenge, arachidonate was lost from all major phospholipid classes (phosphatidylethanolamine greater than phosphatidylcholine greater than phosphatidylinositol). There was a small but significant increase in the amount of label associated with phosphatidic acid during cell activation. Arachidonate was distributed among 1-acyl, 1-alkyl and 1-alk-1-enyl-linked subclasses of PC and PE. The rank order of loss of labelled arachidonate from the major PE and PC subclasses during antigen and ionophore activation was 1-alk-enyl-2-arachidonoyl-GPE greater than 1-acyl-2-arachidonoyl-GPC greater than 1-acyl-2-arachidonoyl-GPE greater than 1-alkyl-2-arachidonoyl-GPC. Labelled products released into the supernatant fluids and free arachidonic acid within the cell accounted for the bulk of arachidonate lost from phospholipids. Labelled products in the supernatant fluids were composed of LTB4, LTC4, PGD2 and free arachidonic acid. BMMC phospholipids were also labelled for 24 hr with [3H]choline, [3H]myoinositol or [14H]ethanolamine and labelled 2-lyso phospholipids were measured after cell activation. Radioactivity in lysophospholipids from PC, PE and PI increased significantly between 30 s and 2 min after antigen activation and then declined. Taken together, these studies suggest that arachidonate is mobilized predominantly from PE and in particular 1-alk-1-enyl-2-arachidonoyl-GPE by the direct removal of arachidonate from the sn-2 position of the molecule. Most of this arachidonate is then released from cells as eicosanoids or free fatty acid.
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PMID:Arachidonic acid metabolism during antigen and ionophore activation of the mouse bone marrow derived mast cell. 189 88

Previous studies have shown that nasal allergen provocation leads to dose-dependent increases of inflammatory mediators, e.g. histamine, kinins, LTC4 and PGD2 in nasal lavages. To investigate further the interaction of these mediators, a titration study with intranasal bradykinin (Bk) application (maximal dose 100 nmol/nostril) and consecutive lavage were performed in eight grass-pollen-allergic patients out of season, and five controls. The nasal lavages were analysed for albumin, N-alpha-tosyl-L-arginine methyl ester (TAME) esterase activity, histamine, 9 alpha,11 beta-PGF2, and LTC4. The clinical reactions were measured with a subjective symptom score. A dose-dependent elevation of albumin was found which was significantly higher in patients with allergic and non-allergic rhinitis compared with normal volunteers. TAME-esterase activity also increased in relation to the dosage of Bk given without significant difference between the various groups. No influence on histamine, LTC4 and 9 alpha,11 beta-PGF2, release (PGD2 metabolite) was seen. Short-lasting clinical symptoms like irritation, sneezing, and obstruction were noticed after the two highest Bk dosages (10 and 100 nmol). We conclude that intranasally applied Bk induces a dose-dependent plasma leakage into the nasal cavity, which is significantly higher in patients with seasonal allergic rhinitis out of season compared to normals. Bk does not seem to affect the mast cell since histamine, LTC4 and 9 alpha,11 beta-PGF2 levels do not alter. The ability to induce relevant symptoms of rhinitis provides strong support for the hypothesis that kinins may be important mediators of inflammatory disorders of the upper airways.
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PMID:Nasal challenge studies with bradykinin: influence upon mediator generation. 191 65

Mast cells and basophils, although sharing many constitutive properties, are quite distinct in their development, functions and biological properties. Mast cell granules are composed of a macromolecular matrix of proteoglycan and neutral protease of which heparin and tryptase, respectively, are predominant. The distribution of the other major neutral protease, chymase, allows human mast cell subpopulations to be subdivided immunocytochemically. All human mast cells respond to IgE-dependent stimulation with the secretion of the preformed mediator, histamine, and the newly generated lipid-derived eicosanoids PGD2 and LTC4. Although amounts of these products vary between mast cells dispersed from different tissues, it is uncertain whether this reflects true heterogeneity. Mast cells of the human skin, but not those of other tissues, are sensitive to stimulation by substance P, compound 48/80 and other basic non-immunological stimuli. The mechanism of mediator secretion induced by these agents is distinct from that induced by IgE-dependent stimulation. However, the morphological characteristics of degranulation are similar, suggesting that the distinct biochemical pathways merge into a common pathway before effecting degranulation.
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PMID:Biological properties of human skin mast cells. 191 78


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