Document Detail

Early onset airway obstruction in response to organic dust in the horse.
MedLine Citation:
PMID:  17158251     Owner:  NLM     Status:  MEDLINE    
Equine recurrent airway obstruction (RAO) has been used as a naturally occurring model of human asthma. However, it is unknown whether there is an early-phase response in RAO. The aim of this study was to determine whether exposure to organic dust induces immediate changes in lung function in RAO-affected horses, which could be mediated by airway mast cells. Six RAO-affected horses in remission and six control horses were challenged with hay-straw dust suspension by nebulization. Total respiratory resistance at 1 Hz, measured by forced oscillation, was increased from 0.62 +/- 0.09 cmH(2)O.l(-1).s (mean +/- SE) to 1.23 +/- 0.20 cmH(2)O.l(-1).s 15 min after nebulization in control horses (P = 0.023) but did not change significantly in the RAO group. Total respiratory reactance at 1 Hz (P = 0.005) was significantly lower in the control horses (-0.77 +/- 0.07 cmH(2)O.l(-1).s) than in the RAO group (-0.49 +/- 0.04 cmH(2)O.l(-1).s) 15 min after nebulization. Bronchoalveolar lavage fluid (BALF) histamine concentration was significantly elevated 10 and 20 min postnebulization in control horses but not in RAO horses. Minimum reactance at 1 Hz in the early postnebulization period significantly correlated with both prechallenge BALF mast cell numbers (r = -0.65, P = 0.02) and peak BALF histamine concentration postnebulization (r = -0.61, P = 0.04). In conclusion, RAO horses, unlike human asthmatic patients, do not exhibit an early-phase response. However, healthy control horses do demonstrate a mild but significant early (<20 min) phase response to inhaled organic dust. This response may serve to decrease the subsequent dose of dust inhaled and as such provide a protective mechanism, which may be compromised in RAO horses.
Christopher M Deaton; Laura Deaton; Eduard Jose-Cunilleras; Thea L Vincent; Alan W Baird; K Dacre; David J Marlin
Publication Detail:
Type:  Journal Article     Date:  2006-12-07
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  102     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2007 Mar 
Date Detail:
Created Date:  2007-03-07     Completed Date:  2007-04-30     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1071-7     Citation Subset:  IM    
Dept. of Physiology, Animal Health Trust, Lanwades Park, Kentford, Suffolk CB8 7UU, UK.
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MeSH Terms
Bronchial Provocation Tests / veterinary
Bronchoalveolar Lavage Fluid / chemistry,  cytology
Histamine / analysis
Horse Diseases / physiopathology*
Inflammation / physiopathology,  veterinary*
Lung Diseases, Obstructive / physiopathology,  veterinary*
Mast Cells / physiology*
Respiratory Function Tests / veterinary
Reg. No./Substance:
0/Dust; 51-45-6/Histamine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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