Methacholine and ovalbumin challenges assessed by forced oscillations and synchrotron lung imaging
| Autor: | Heikki Suhonen, Pekka Suortti, Ferenc Peták, Sam Bayat, Satu Strengell, Zoltán Hantos, Walid Habre, Tibor Z. Jánosi, Liisa Porra, Anssi Sovijärvi |
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| Rok vydání: | 2009 |
| Předmět: |
Pathology
Provocation test 030204 cardiovascular system & hematology Critical Care and Intensive Care Medicine Bronchoconstrictor Agents 0302 clinical medicine Disease Models Animal Image Processing Computer-Assisted Infusions Intravenous Lung Lung Compliance Methacholine Chloride Airway Resistance/physiology Respiratory Mechanics/*physiology biology ddc:617 Bronchoconstrictor Agents/*diagnostic use Respiratory disease Allergens/*diagnostic use/immunology respiratory system Ovalbumin/*diagnostic use/immunology medicine.anatomical_structure Lung Compliance/physiology Rabbits Bronchial Hyperreactivity Bronchial Hyperreactivity/*physiopathology hormones hormone substitutes and hormone antagonists medicine.drug Methacholine Chloride/*diagnostic use Pulmonary and Respiratory Medicine medicine.medical_specialty Oscillometry Ovalbumin Bronchial Provocation Tests Bronchial Provocation Tests/*methods 03 medical and health sciences Forced Oscillation Technique Internal medicine Intensive care Administration Inhalation medicine Animals Synchrotrons Tomography X-Ray Computed Asthma Pulmonary Ventilation/physiology Dose-Response Relationship Drug business.industry Airway Resistance Lung/physiopathology Allergens medicine.disease Endocrinology 030228 respiratory system biology.protein Respiratory Mechanics Methacholine business Pulmonary Ventilation |
| Zdroj: | American Journal of Respiratory and Critical Care Medicine, Vol. 180, No 4 (2009) pp. 296-303 |
| ISSN: | 1535-4970 1073-449X |
| Popis: | RATIONALE: Methacholine (Mch) is routinely used to assess bronchial hyperreactivity; however, little is known about the differences in the lung response pattern between this provocation and that observed with ovalbumin (Ova) after allergic sensitization. OBJECTIVES: To compare (1) the central versus peripheral effects of Mch and Ova within the lung by combining measurements of airway and tissue mechanics with synchrotron radiation (SR) imaging, and (2) to assess the extent to which mechanical and imaging parameters are correlated. METHODS: We used the low-frequency forced oscillation technique and SR imaging in control (n = 12) and ovalbumin-sensitized (n = 13) rabbits, at baseline, during intravenous Mch infusion (2.5 microg/kg/min, 5.0 microg/kg/min, or 10.0 microg/kg/min), after recovery from Mch, and after intravenous Ova injection (2.0 mg). We compared intravenous Mch challenge with inhaled Mch (125 mg/ml, 90 s) in a separate group of control animals (n = 5). MEASUREMENTS AND MAIN RESULTS: Airway conductance and tissue elastance were measured by low-frequency forced oscillation technique. The central airway cross-sectional area, the ventilated alveolar area, and the heterogeneity of specific ventilation were quantified by SR imaging. Mch infusion induced constriction predominantly in the central airways, whereas Ova provocation affected mainly the peripheral airways, leading to severe ventilation heterogeneities in sensitized animals. Mch inhalation affected both conducting and peripheral airways. The correlations between airway conductance and central airway cross-sectional area (R = 0.71) and between tissue elastance and ventilated alveolar area (R = -0.72) were strong. CONCLUSIONS: The pattern of lung response caused by intravenous Mch and Ova are fundamentally different. Although inhaled Mch induces a heterogeneous lung response similar to that observed with intravenous allergen, these similar patterns are due to different mechanisms. |
| Databáze: | OpenAIRE |
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