Permeability of the Bronchial Mucosa to<sup>99m</sup>Tc-DTPA in Asthma

Ilowite, Jonathan S.; Bennett, William D.; Sheetz, Maurice S.; Groth, Maritza L.; Nierman, David M.

doi:10.1164/ajrccm/139.5.1139

Cited by 84 publications

(54 citation statements)

References 7 publications

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“…5) Clearance during data acquisition could contribute to the reduction in the apparent difference in PI between aerosols of different tonicities. Over the period of time in our experiments, about 10-20% of the radioactivity would be expected to be cleared from the central and peripheral regions, both in normal and in asthmatic subjects [35,36]. Mucociliary clearance (MCC) was shown to be faster after nonisotonic aerosols [37,38].…”

Section: Discussionmentioning

confidence: 99%

Regional deposition of saline aerosols of different tonicities in normal and asthmatic subjects

Phipps

Gonda²,

Anderson³

et al. 1994

Eur Respir J

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R Re eg gi io on na al l d de ep po os si it ti io on n o of f s sa al li in ne e a ae er ro os so ol ls s o of f d di if ff fe er re en nt t t to on ni ic ci it ti ie es s i inABSTRACT: Nonisotonic aerosols are frequently used in the diagnosis and therapy of lung disease. The purpose of this work was to study the difference in the pattern of deposition of aerosols containing aqueous solutions of different tonicities. 99m Technetium-diethyltriaminepentaacetic acid ( 99m Tc-DTPA)-labelled saline aerosols, with mass median aerodynamic diameter 3.7-3.8 µm and geometric standard deviation 1.4, were inhaled under reproducible breathing conditions on two occasions. Hypotonic and hypertonic solutions were used in 11 normals subjects, isotonic and hypertonic solutions in 9 asthmatics. The regional deposition was quantified by a penetration index measured with the help of a tomographic technique.There was a small but significant increase (6.7%) in the penetration index of the hypotonic as compared to the hypertonic aerosols in the normal subjects. The region that was markedly affected was the trachea. The differences in the penetration of the isotonic and hypertonic aerosols in the asthmatics appeared to be strongly dependent on the state of the airways at the time of the study.These findings can be interpreted in terms of effects of growth or shrinkage of nonisotonic aerosols, as well as of airway narrowing, on regional deposition of aerosols. Tonicity of aerosols appears to affect their deposition both through physical and physiological mechanisms. This should be taken into account when interpreting the effects of inhaled aqueous solutions of various tonicities in patients in vivo.

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Section: Discussionmentioning

confidence: 99%

Regional deposition of saline aerosols of different tonicities in normal and asthmatic subjects

Phipps

Gonda²,

Anderson³

et al. 1994

Eur Respir J

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“…Airway mucosal permeability is increased in smokers with normal lung function and in asthmatic patients who do not smoke. 99,100 Another proposed mechanism of corticosteroid resistance is the down-regulation of ß 2 -adrenergic receptors in lymphocytes that is caused by cigarette smoking. 101 Changes in levels of cytokines and inflammatory mediators may also play a role.…”

Section: Mechanisms Of Corticosteroid Resistancementioning

confidence: 99%

Smoking and Asthma

Stapleton

Howard-Thompson²,

George³

et al. 2011

The Journal of the American Board of Family Medicine

139

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Background:The purpose of this review is to describe the current understanding of the prevalence and adverse effects of cigarette smoking and secondhand smoke (SHS) in asthmatics in terms of patient outcomes and response to inhaled corticosteroids.Methods: We searched the English biomedical literature via PubMed, Embase, and Scopus using the terms "smoking and asthma," "secondhand smoke and asthma," "environmental tobacco smoke and asthma," and "smoking/secondhand smoke and corticosteroids." We also reviewed reference lists of identified articles for relevant citations.Results: In asthmatic patients who smoke, disease control is poorer than in asthmatic nonsmokers. Of all forms of SHS, maternal exposure seems to have the largest impact on asthma by increasing the frequency and severity of the disease and decreasing lung function. Asthmatic children exposed to multiple household smokers face an increased risk for respiratory illness-related absences from school, and these effects persist during adolescence but weaken during adulthood. Airway mucosal permeability is increased in smokers, which could lead to increased clearance of inhaled corticosteroids from the airways. Smokers also have decreased histone deacetylase activity, which is necessary for corticosteroids to fully suppress cytokine production, and can lead to corticosteroid resistance.

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“…Because of this feature, the lung retention ratio depends mainly on the permeability in the peripheral lung, where the mucociliary transport takes place very slowly [19]. Previous reports have demonstrated that airway permeability is increased in unstable asthmatics [20] and COPD patients [21], but not in stable asthmatics [22]. In the present study, the retention ratio of the right peripheral lung at 60 min after inhalation was significantly lower in COPD patients than in normals, suggesting that the epithelial permeability of the small airways and alveoli may be increased in COPD subjects.…”

Section: Discussionmentioning

confidence: 99%

Deposition and clearance of inhaled 18FDG powder in patients with chronic obstructive pulmonary disease

Yanai

Hatazawa

Ojima³

et al. 1998

Eur Respir J

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As freon is limited in its use as a generator for aerosol inhalation, powder particles are used as an alternative for inhalation therapy. The pulmonary deposition and clearance of inhaled powder particles was studied by positron emission tomography (PET) in ten patients with chronic obstructive pulmonary disease (COPD) and in five normal controls. The powder, 5 microm in mean diameter, was water soluble and labelled with 2-deoxy-2-[18F]-fluoro-D-glucose (18FDG). Powder inhalation was done with single deep inspiration from residual volume to total lung capacity. The initial deposition ratio in the right or left lung field to total inhaled dose, measured by an anteroposterior rectilinear scan, did not differ between normals and COPD patients. Ratios of radioactivity detected within the central and peripheral regions (the central to peripheral ratio) measured by the PET scan was not significantly different between COPD patients (4.8+/-2.6, mean+/-SD) and normals (2.6+/-0.8, mean+/-SD). However, the regional powder deposition in peripheral lung fields measured by the PET scan was significantly more uneven in COPD patients than in normal patients. The clearance rate of 18FDG, defined as the retention ratio of 18FDG activity to the initially deposited 18FDG at 60 and 120 min after inhalation, in the trachea, large bronchi or peripheral lung fields measured by tomographic scan showed a wider variation in COPD patients than in normals. To conclude, inhaled powder tended to be deposited more centrally and was distributed more unevenly in the peripheral lung in chronic obstructive pulmonary disease patients than in normals. This could be a limitation of powder inhalation used for therapy in chronic obstructive pulmonary disease patients.

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Permeability of the Bronchial Mucosa to^99mTc-DTPA in Asthma

Cited by 84 publications

References 7 publications

Regional deposition of saline aerosols of different tonicities in normal and asthmatic subjects

Regional deposition of saline aerosols of different tonicities in normal and asthmatic subjects

Smoking and Asthma

Deposition and clearance of inhaled 18FDG powder in patients with chronic obstructive pulmonary disease

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Permeability of the Bronchial Mucosa to99mTc-DTPA in Asthma

Cited by 84 publications

References 7 publications

Regional deposition of saline aerosols of different tonicities in normal and asthmatic subjects

Regional deposition of saline aerosols of different tonicities in normal and asthmatic subjects

Smoking and Asthma

Deposition and clearance of inhaled 18FDG powder in patients with chronic obstructive pulmonary disease

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Product

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Permeability of the Bronchial Mucosa to^99mTc-DTPA in Asthma