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

Oxidant exposure of the airway mucosa may play a significant role in the pathophysiology of asthma and allergic rhinitis. Mast cells play an important role in asthma, and oxidant exposure has been reported to cause direct mast cell degranulation as well as augment immunoglobulin E (IgE)-mediated responses in vivo. H2O2 is an oxidant generated by inflammatory cells and by the interaction of ozone with lipids or aqueous solutions. In this study, the RBL-2H3 mast cell line was used to investigate the ability of H2O2 to induce mast cell responses as well as to effect mast cell responses to IgE and the calcium ionophore A23187. Although cytotoxicity of RBL-2H3 cells at the membrane level was not observed with any concentration of H2O2, DNA damage resulted from exposure to 0.2 and 2.0 mM H2O2, and cell proliferation was inhibited by 0.075-0.2 mM H2O2. RBL cell prostaglandin D2 generation was enhanced after 60- and 120-min exposure to 0.2-20 mM H2O2. Direct serotonin release required 120-min exposures to 2.0 mM and 60-min exposures to 20 mM H2O2. However, degranulation responses induced by either IgE or A23178 were diminished after exposure to 0.2-2.0 mM H2O2. Lesser amounts (0.005-0.02 mM) had no effect on mast cell function. In summary, H2O2-induced responses of RBL cells, as well as modification of responses to IgE and A23187, occurred only at high concentrations of H2O2, which also induced both intracellular damage and inhibition of cell proliferation. Concentrations of H2O2 more likely to be physiologically relevant had no effect on mast cell responses or cytotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hydrogen peroxide effects on rat mast cell function. 804 46

Allergic rhinosinusitis has three forms of therapy: pharmacotherapy, immunotherapy, and surgical therapy. Pharmacotherapeutically, there are six classes of drugs that give symptomatic relief: mucolytics, decongestants, anti-cholinergic agents, antihistamines, mast cell stabilizers, and corticosteroids. All six classes are discussed individually and in detail. For immunotherapeutic therapy of allergic rhinosinusitis, there are four types of skin testing in current use: scratch testing, prick testing, single intradermal testing, and skin end point titration testing. Only the latter is able to quantitate the antigenicity of each antigen, and thus the treatment vial made from only this type of skin testing can adequately treat all antigens to which the patient is sensitive. These differences in testing and vial mixing are explained. The last form of therapy is surgical therapy, which corrects the obstructive phenomenon caused by allergic rhinosinusitis. The procedures described are reduction inferior turbinectomies and endoscopic sinus surgery. It is felt by the authors that the specialist who is uniquely positioned to offer a patient suffering from allergic rhinosinusitis all three forms of therapy is the rhinologist.
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PMID:Allergic rhinosinusitis: the total rhinologic disease. 834 84

Antihistamines are believed to reduce the sneezing and rhinorrhea associated with allergic rhinitis, primarily by competitive antagonism of histamine for H1 cellular receptors, but additional mechanisms of action may contribute to their clinical efficacy. To improve our understanding of H1 antihistamine action, we studied the effects of pretreatment with terfenadine, cetirizine, ketotifen, azatadine, diphenhydramine, and azelastine on increases in vascular permeability, mast cell activation, and sneezing induced by nasal challenge with antigen. All studied antihistamines reduced sneezing, indicating that they all effectively antagonize histamine after its release. In addition, terfenadine and topically administered azatadine blocked the release of histamine. Studies with cetirizine and azelastine revealed that these antihistamines significantly reduced sulfidopeptide leukotriene levels. Terfenadine and azelastine also reduced kinin production. These results confirm that antihistamines are effective in reducing sneezing and, in some cases, vascular permeability. The findings of these studies also illustrate that the various antihistamines have multiple and different mechanisms of action that may have implications for their clinical uses.
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PMID:The effect of antihistamines on the immediate allergic response: a comparative review. 810 58

Nasal allergy is due to a change in the immunoreactivity of an individual. B-lymphocytes produce allergen-specific IgE antibodies after the antigen is presented to T-helper cells. IgE bound to mast cells leads to mast cell activation in the case of antigen contact. Mast cells release mediators and induce local inflammation. The symptoms of allergic rhinitis are caused by various factors and are different in individuals, and hence therapy must be in accordance with the necessities in the individual. There are four principles of therapy in allergic rhinitis. The first and best is allergen avoidance. It is the first choice in animal allergy and important in mite allergy. It is difficult for mold allergy and impossible for pollen allergy. The second is immunotherapy. Immunotherapy is a specific form of controlled allergen admission that changes immunoreactivity into allergen tolerance in a major part of patients. Immunotherapy is a very important tool if performed by a physician with experience. The third principle is drug therapy. With todays drugs, it is still symptomatic. alpha-sympathomimetic vasoconstrictors administered systemically (and, still better, locally) relieve nasal stuffiness. Parasympatholytic drugs can abort pathological secretions. Cromoglycate (DNCG) is a local prophylactic drug improving all symptoms of allergic rhinitis. DNCG is the first choice in pollinosis. Antihistamines are usually given systemically, and the modern drugs have no sedative effect. Clinical effects are comparable to DNCG, and there are new substances available for local therapy. Steroids given systematically improve all symptoms of allergy and inflammation after a certain delay. Due to side effects, local steroids are preferred today.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Therapy of allergic rhinitis]. 810 4

Nasal biopsies to naturally occurring allergic rhinitis demonstrate ultrastructural evidence of mast cell degranulation. Consistent with this, H1 antihistamines are clinically efficacious in this disorder. The nasal symptoms of itch, sneeze and discharge are, however, more susceptible to this mode of therapy than is nasal blockage. As nasal blockage is vascular, the combination of an H1 antihistamine and a decongestant has a logical rationale. To investigate the efficacy of such a combination, the influence of pretreatment with terfenadine, 60 mg, pseudo-ephedrine, 120 mg, Seldane-d (a registered trademark of Marion Merrell Dow)--a combination of pseudo-ephedrine, 120 mg, and terfenadine, 60 mg,--and matched placebo was objectively investigated on the nasal response to allergen in grass-pollen-sensitive seasonal rhinitic subjects (7 males, 7 females, age 19-56 years) in a double-blind, placebo-controlled, 4-period cross-over study. Seldane-D was significantly better than placebo in all efficacy measurements: nasal itch (p < 0.02), sneezing (p < 0.01), discharge (p < 0.01) and blockage (p < 0.003). The terfenadine component of Seldane-D contributed predominantly to the reduction in itch, sneeze and discharge (p < 0.01) while the pseudo-ephedrine component primarily contributed to the nasal airway effects (p < 0.04). These results indicate that the combination of terfenadine and pseudo-ephedrine as a single oral medication is complementary.
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PMID:The influence of terfenadine and pseudo-ephedrine alone and in combination on allergen-induced rhinitis. 832 95

The distribution and abundance of mast cells in nasal polyps, the maxillary sinus mucosa of patients with sinusitis and the turbinate mucosa of allergic rhinitis was microscopically examined using different methods of fixation. In the epithelium of the surface and the ducts of nasal polyps (n = 8), the mean number of mast cells was over 20,000 per mm3 using Mota's fixation and the increase was correlated with the epithelial thickness (P < 0.05). On the other hand those of the maxillary sinus mucosa (n = 6) and the nasal turbinate mucosa (n = 7) were less than 6,000 per mm3. In the subepithelial layer or areas deeper than the area with the glands, however, mast cell counts were less than 3,200 per mm3 in all diseases. More than 70-90 per cent of all mast cells in the epithelium of the mucosal surface and the ducts of the polyp, the maxillary sinus mucosa and nasal turbinates were formalin sensitive. Most of the mast cells in the subepithelial and deeper areas were formalin resistant in all diseases. These results suggest that conditions for mast cell growth differ between polyps and the other diseases, and that the conditions which affect mast cells may contribute to polyp development.
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PMID:Mast cell quantitation in nasal polyps, sinus mucosa and nasal turbinate mucosa. 832 21

Allergic mucosal inflammation is characterized by the presence of cell infiltration, predominantly with IgE-sensitized mast cells and activated eosinophils, and appears to be regulated by the local production and release of several cytokines, particularly IL-4 and IL-5. Although attention has focused on the Th2 subpopulation of CD4+ T lymphocytes as an important source of these cytokines, human mast cells have been shown to both store and secrete IL-4 and TNF-alpha. To investigate the expression of cytokines relevant to allergic inflammation and to identify their cellular localization within the nasal mucosa, we have undertaken specific immunohistochemical staining of thin sections of inferior turbinate biopsies from patients with perennial allergic rhinitis and, for comparison, from nonatopic healthy volunteers. The cytokines investigated were IL-4, IL-5, IL-6, and IL-8. In both the normal and rhinitic biopsies numerous cells immunoreactive for IL-4, IL-5, and IL-6 were seen. Staining of adjacent 2-microns sections for CD3, mast cell tryptase, and eosinophil cationic protein revealed that 90% of the IL-4 immunoreactive cells were mast cells, with biopsies from rhinitic subjects containing significantly more IL-4+ cells than biopsies from normal controls (p = 0.02), especially when assessed with the anti-IL-4 mAb 3H4. Mast cells also accounted for > 90% of IL-6 and > 50% of IL-5 immunoreactive cells. IL-5 immunoreactivity was also localized to eosinophils, whereas IL-8 localized predominantly to the nasal epithelium in both groups. No cytokines were found in association with T lymphocytes. These findings indicate that the mast cell is an important source of preformed cytokines and as such may contribute to the chronicity of the mucosal inflammation that characterizes allergic rhinitis.
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PMID:Immunolocalization of cytokines in the nasal mucosa of normal and perennial rhinitic subjects. The mast cell as a source of IL-4, IL-5, and IL-6 in human allergic mucosal inflammation. 837 6

Tryptase is a mast cell-specific marker of degranulation. To investigate the possible diagnostic value of tryptase in allergic rhinitis, we measured the levels in both serum and native nasal fluid with a sandwich RIA-assay (Pharmacia). Twenty-three allergic patients and five patients with chronic ethmoidal sinusitis were included. Eighteen of the 23 allergic patients were tested within the pollen season or had perennial rhinitis; the remainder were tested at least 1 month out of the pollen season. None of the patients had detectable serum tryptase (> 0.1 ng/ml). Also patients with chronic ethmoidal sinusitis showed no tryptase in nasal fluid. One of seven allergic patients tested out of season had slightly increased nasal tryptase of 1.8 ng/ml. In patients with active nasal allergy, the tryptase in nasal fluid ranged from 6.4 ng/ml to 640 ng/ml with a mean of 101 ng/ml and SD 173. These results show a clear distinction between active and non-active nasal allergy and other non-mast-cell-related nasal disease. Further, nasal tryptase release by natural allergen exposure is even higher than that observed in allergen challenge tests.
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PMID:Tryptase in nasal fluid is a useful marker of allergic rhinitis. 845 35

The pathogenesis of allergic rhinitis is complex, involving not only histamine and mast cell-derived tryptase, but also eosinophil- and neutrophil-derived mediators, cytokines, and intercellular cell adhesion molecules (ICAM-1). It is surprising that antihistamines, which block only one component of the process, have proved so effective in the management of allergic rhinitis. Research has therefore focused on whether antihistamines have additional pharmacological activities. In vitro studies have shown that high concentrations of second generation antihistamines can block inflammatory mediator release from basophils and mast cells, and reduce ICAM-1 expression in epithelial cell lines. In vivo studies have also shown an effect on the allergen-induced inflammatory reaction; both oral and intranasal antihistamines cause a reduction in nasal symptoms and inflammatory cell influx. Oral terfenadine and cetirizine and intranasal levocabastine and azelastine have also demonstrated a lowering of ICAM-1 expression on epithelial cells. With regard to clinical efficacy, topical levocabastine (0.5 mg/mL eye drop solution and 0.5 mg/mL nasal spray) was shown to be more effective than oral terfenadine (60 mg twice daily) in relieving ocular itch (P = 0.02) and reducing nasal symptoms in allergic rhinoconjunctivitis. In a further study, levocabastine eye drops were as effective and well tolerated as sodium cromoglycate in seasonal allergic rhinitis. Intranasal azelastine (0.28 mg twice daily) showed a trend for superior relief of rhinorrhoea and nasal obstruction compared with oral terfenadine (60 mg twice daily). In addition, intranasal azelastine (0.28 mg twice daily) resulted in significant reductions in sneezing, nasal obstruction, rhinorrhoea and itching in perennial rhinitis, compared with the lower efficacy of beclomethasone dipropionate (0.1 mg twice daily). As well as benefits in efficacy, topical administration is associated with improved safety. Some antihistamines, particularly those metabolized in the liver, are associated with occasional reports of severe side-effects. It is therefore logical to administer antihistamines directly to the target organ.
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PMID:Antihistamines: topical vs oral administration. 873 53

Epidemiological data indicated that allergic rhinitis often coexists with and may precede the development of reactive airway disease. In particular, ARP with BHR are more likely to develop asthma. However, the pathogenesis of BHR associated with allergic rhinitis is still remains uncertain. Therefore we designed the study on ARP with/without BHR. The aim of this study were to investigate the presence of an inflammatory process in lower respiratory tract in ARP and to relate these changes to airway responsiveness Eleven ARP with BHR (Group I), eleven ARP without BHR (Group II) and two control patients (Control group) were studied. All of the ARP were judged atopic on the basis of positive skin prick test to common inhalant allergens. Bronchial challenges were performed with increasing concentration of M. All the subjects underwent fiberoptic bronchoscopy, BAL and bronchial biopsies were obtained for pathologic examination. The mean total cell and the mean percentage of macrophages, lymphocytes, neutrophils and eosinophils in BAL fluid were in normal range in all groups without any significant differences between the groups. There weren't any correlation between PC20 to M and the total cell counts and percentage counts of these cells. In bronchial biopsy samples, the absolute numbers of lymphocytes, neutrophils, eosinophils and mast cells in the submucosa showed no differences between the three groups. The epithelial shedding was more extensive in ARP than control subjects (p = 0.05). The thickness of the epithelium was prominent in Group I (p < 0.05) but there was no significant differences in the basement membrane thickening between the three groups. We could only find an inverse correlation between PC20 to M and the mast cell counts in the submucosa (r xy:-0.815 p < 0.05). In conclusion, we couldn't observe any prominent morphological changes which indicate that may cause of BHR in ARP except the increased epithelial shedding in Group I. However, the increased epithelial shedding is not a reliable criterion to comment because of the possibility of mechanical damage of bronchial biopsies caused by the forceps.
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PMID:The mechanism of bronchial hyperreactivity in allergic rhinitis patients. A light microscopic study on BAL and bronchial biopsy. 893 89


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