| THE OCCURRENCE OF REFRACTORINESS AND MAST CELL MEDIATOR RELEASE FOLLOWING MANNITOL-INDUCED BRONCHOCONSTRICTION. | |
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MedLine Citation:
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PMID: 21252215 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Background: For several hours after exercise-induced bronchoconstriction, there is diminished responsiveness to repeated challenge. The mechanism causing this refractoriness is unclear. Inhalation of dry powder mannitol is a new bronchial provocation test that has been suggested as a surrogate for an exercise challenge. Refractoriness to repeated mannitol challenge has however not been established. Objective: To investigate if repeated challenge with mannitol is associated with refractoriness and diminished release of mast cell mediators of bronchoconstriction. Methods: Sixteen subjects with asthma underwent repeated inhalation of mannitol 90 minutes apart. Lung function was assessed by forced expiratory volume in one second (FEV(1)). The urinary excretion (ng per mmol creatinine) of the mediators 9α,11β-prostaglandin(PG) F(2) and leukotriene(LT) E(4) were measured. Results: The group mean fall in FEV(1) after the second challenge was 48.5±5.8 % of the first (p<0.001). The protection afforded by the initial challenge however varied considerably between subjects (range 88-0 %). Furthermore, the urinary excretion of the two mediators was increased after both challenges. The average excretion of mediators after the challenges was significantly higher for the six most refractory subjects. This was observed both for LTE(4) (95.6±5.2 vs. 58.0±2.4 for the six least refractory) (P<0.001) and for 9α,11β-PGF(2) (137.6±6.7 vs. 50.1±1.1 for the six least refractory) (P=0.002). Conclusion: As occurs with exercise-induced bronchoconstriction, repeated inhalation of mannitol induced refractoriness. We propose that refractoriness is due to tachyphylaxis at the level of the airway smooth muscle responsiveness to mediators of bronchoconstriction rather than due to fatigue of their release from mast cells. |
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Authors:
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Johan Robert Larsson; Clare P Perry; Sandra D Anderson; John D Brannan; Sven-Erik Dahlen; Barbro Dahlen |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-1-20 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: - ISSN: 1522-1601 ISO Abbreviation: - Publication Date: 2011 Jan |
Date Detail:
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Created Date: 2011-1-21 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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1The National Institute of Environmental Medicine, Karolinska Institutet. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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