The influence of aerosol retention and pattern of deposition on bronchial responsiveness to atropine and methacholine in humans

Journal Article · Fri Dec 01 04:00:00 EST 1989 · American Review of Respiratory Disease (New York); (USA)

DOI:https://doi.org/10.1164/ajrccm/140.6.1727· OSTI ID:7244560

Gillett, M K; Briggs, B A; Snashall, P D ^[1]

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1. Charing Cross and Westminster Medical School, London (England)

We have examined the influence of total intrapulmonary deposition and its pattern on the bronchial response to aerosolized methacholine and atropine in 10 normal and 12 asthmatic subjects. On Day 1 we performed a dose-response challenge to methacholine and defined responsiveness as the provocative dose (PD35) needed to cause a 35% decrease in specific airway conductance (SGaw). On Day 2 we repeated methacholine challenge after premedication with aerosolized atropine, and we defined the response to atropine as dose ratio-1 (DR-1) where DR = PD35 after atropine/PD35 without atropine. On Day 3 we imaged intrapulmonary aerosol deposition by mixing 99mtechnetium with methacholine aerosol and scanning the thorax with a gamma camera during the development of bronchoconstriction. Total pulmonary aerosol deposition varied considerably between individuals (1.2 to 23.6% of nebulized dose) but there was no difference between normal and asthmatic subjects, and no correlation between deposition and baseline SGaw or PD35; there was a significant positive correlation between deposition and DR-1. Deposition of aerosol in central lung zones was inversely related to SGaw and correlated positively with DR-1; there was no significant relationship with PD35. Total intrapulmonary aerosol deposition and its pattern partially determine bronchial responsiveness to atropine, but we have not demonstrated any significant effect on responsiveness to methacholine.

• OSTI ID: 7244560
• Journal Information: American Review of Respiratory Disease (New York); (USA), Journal Name: American Review of Respiratory Disease (New York); (USA) Vol. 140:6; ISSN ARDSB; ISSN 0003-0805
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AEROSOLS
ALCOHOLS
ALKALOIDS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
ASTHMA
ATROPINE
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
BODY AREAS
BRONCHI
CAMERAS
CHEST
CHOLINE
COLLOIDS
DIAGNOSIS
DISEASES
DISPERSIONS
DOSE-RESPONSE RELATIONSHIPS
DRUGS
GAMMA CAMERAS
HOURS LIVING RADIOISOTOPES
HYDROXY COMPOUNDS
IMAGE PROCESSING
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIPOTROPIC FACTORS
LUNGS
MAMMALS
MAN
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PARASYMPATHOLYTICS
PRIMATES
PROCESSING
QUATERNARY COMPOUNDS
RADIOISOTOPES
RESPIRATORY SYSTEM
RESPIRATORY SYSTEM DISEASES
RETENTION
SOLS
TECHNETIUM 99
TECHNETIUM ISOTOPES
TRACER TECHNIQUES
VERTEBRATES
YEARS LIVING RADIOISOTOPES