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Chest Oct 2005To evaluate quantitative air trapping measurements in children with mild cystic fibrosis (CF) lung disease during a 1-year, double-blind, placebo-controlled, recombinant... (Clinical Trial)
Clinical Trial Comparative Study Randomized Controlled Trial
PURPOSES
To evaluate quantitative air trapping measurements in children with mild cystic fibrosis (CF) lung disease during a 1-year, double-blind, placebo-controlled, recombinant human deoxyribonuclease (rhDNase) [dornase alfa] intervention trial and compare results from quantitative air trapping with those from spirometry or visually scored high-resolution CT (HRCT) scans of the chest.
MATERIALS AND METHODS
Twenty-five children with CF randomized to either daily rhDNase or placebo aerosol were evaluated at baseline, and at 3 months and 12 months by spirometer-triggered HRCT and spirometry. Outcome variables were percentage of predicted FVC, FEV1, and forced expiratory flow, midexpiratory phase (FEF(25-75%)); total and subcomponent visual HRCT scores; and quantitative air trapping measurements derived from chest HRCT images.
RESULTS
At baseline, there were no statistical differences between groups in any of the variables used as an outcome. After 3 months of treatment, both groups had improvements in percentage of predicted FEV1 and FEF(25-75%), and total HRCT visual scores. In contrast, the rhDNase group had a 13% decrease in quantitative air trapping from baseline (severe air trapping [A3]), compared to an increase of 48% in the placebo group (p = 0.023). After 12 months, both groups had declines in percentage of predicted FVC and FEV1, but the rhDNase group retained improvements in percentage of predicted FEF(25-75%) and quantitative air trapping. The mucus plugging and total HRCT visual scores were also improved in the rhDNase group after 12 months of treatment, with and without significant differences between groups (p = 0.026 and p = 0.676). Quantitative air trapping (A3) remained improved in the rhDNase group (- 15.4%) and worsened in the placebo group (+61.3%) with nearly significant differences noted between groups (p = 0.053) after 12 months of treatment.
CONCLUSIONS
Quantitative air trapping is a more consistent sensitive outcome measure than either spirometry or total HRCT scores, and can discriminate differences in treatment effects in children with minimal CF lung disease.
Topics: Air; Child; Cystic Fibrosis; Deoxyribonuclease I; Double-Blind Method; Humans; Placebos; Respiratory Function Tests; Tomography, X-Ray Computed
PubMed: 16236891
DOI: 10.1378/chest.128.4.2327 -
European Radiology 2000The aim of this study was to evaluate bronchial and lung abnormalities in patients suffering from moderate asthma as defined by international guidelines, with special...
The aim of this study was to evaluate bronchial and lung abnormalities in patients suffering from moderate asthma as defined by international guidelines, with special attention to air trapping on CT in comparison with that detected in smoking and non-smoking normal subjects. Twenty-two patients classified as moderate asthma and control subjects including healthy volunteers, smokers (n = 10) or non-smokers (n = 12) were prospectively explored by high-resolution CT (HRCT) performed at suspended full inspiration and expiration. The same expiratory protocol was performed 15 min after inhalation of 200 microg of salbutamol. Patients underwent pulmonary function tests within the same week and bronchodilator response was assessed following inhalation of salbutamol. Abnormalities of bronchi and lung parenchyma on inspiratory CT and air trapping on expiratory CT, in dependent and non-dependent areas, were assessed and scored semi-quantitatively by two independent observers. Comparison of score mean values between the different groups was performed using Mann-Whitney test and Spearman correlation between CT findings and pulmonary function tests were calculated. Mosaic perfusion was observed in 23% of asthmatics. Air-trapping scores were significantly higher in asthmatic patients than in non-smoking control subjects (p = 0.003), but not than in smokers. This difference was ascribed to non-dependent zones of the lung for which air-trapping scores were also higher in asthmatic patients (p = 0.003) and in smoking subjects (p = 0.004) than in normal controls. In the asthmatic group, a significant positive correlation was found between airways resistance and bronchial dilatation score (p = 0.01), and between small airways obstruction index and mosaic perfusion score (p = 0.05). In addition, both FEV1 and reversibility of small airways obstruction values correlated with air-trapping score (p = 0.03 and p = 0.007, respectively). No change could be detected in air-trapping score following salbutamol inhalation. Patients suffering from moderate asthma present mosaic perfusion and larger areas of air trapping than normal subjects, particularly in non-dependent areas of the lung. These lung abnormalities are related to small airways obstruction.
Topics: Administration, Inhalation; Adult; Aged; Air; Albuterol; Asthma; Bronchodilator Agents; Bronchography; Female; Humans; Lung; Male; Middle Aged; Respiration; Respiratory Mechanics; Smoking; Tomography, X-Ray Computed
PubMed: 10997428
DOI: 10.1007/s003300000504 -
Langmuir : the ACS Journal of Surfaces... Jun 2015We report that at very low initial bulk concentrations, a couple of hundred times below the critical micellar concentration (CMC), anionic surfactant sodium dodecyl...
We report that at very low initial bulk concentrations, a couple of hundred times below the critical micellar concentration (CMC), anionic surfactant sodium dodecyl sulfate (SDS) adsorbed at the air-water interface of a gas bubble cannot be removed, on the time scale of the experiment (hours), when the surrounding solution is gently replaced by pure water. Extremely sensitive interferometric measurements of the resonance frequency of the bubble-forced oscillations give precise access to the concentration of the surfactant monolayer. The bulk-interface dynamic exchange of SDS molecules is shown to be inhibited below a concentration which we believe refers to a kind of gas-liquid phase transition of the surface monolayer. Above this threshold we recover the expected concentration-dependent desorption. The experimental observations are interpreted within simple energetic considerations supported by molecular dynamics (MD) calculations.
Topics: Adsorption; Air; Micelles; Sodium Dodecyl Sulfate; Solutions; Surface Properties; Surface-Active Agents; Thermodynamics; Water
PubMed: 26039913
DOI: 10.1021/la504677a -
Respiration; International Review of... 2009Air trapping evaluated in high-resolution computed tomography (HRCT) reflects changes in small bronchi. We simultaneously evaluated focal and diffuse air trapping in... (Comparative Study)
Comparative Study
BACKGROUND
Air trapping evaluated in high-resolution computed tomography (HRCT) reflects changes in small bronchi. We simultaneously evaluated focal and diffuse air trapping in asthmatic patients.
OBJECTIVES
(1) To evaluate air trapping and bronchial wall thickness in asthmatics. (2) To estimate the relationship between air trapping and bronchial wall thickness, pulmonary function tests (PFTs), age, gender and asthma severity. (3) To compare air trapping between subgroups of asthmatic patients with normal FEV(1) % pred. and FEV(1)/FVC % and controls. (4) To compare air trapping and bronchial wall thickness between aspirin-induced asthmatics (AIA) and aspirin-tolerant asthmatics (ATA).
METHODS
Both groups (asthmatics and controls) included 30 patients. All patients underwent HRCT and PFTs.
RESULTS
Focal (p < 0.0001) and diffuse (p = 0.0004) air trappings and bronchial wall thickness (T: p < 0.0001; T/D: p < 0.0001; WA%: p < 0.0001) were significantly greater in asthmatics. Focal and diffuse air trappings were inversely correlated (p = 0.021). Diffuse air trapping correlated with bronchial wall thickness: T/D (p = 0.047), T (p = 0.037), and WA% (p = 0.048). There was a significant difference in the extent of focal air trapping between a subgroup of asthmatics with normal FEV(1) % pred. and FEV(1)/FVC % and controls (p < 0.0001). There were no significant differences in focal (p = 0.095) and diffuse air trapping (p = 0.186) and bronchial wall thickness (T: p = 0.086; T/D: p = 0.428; WA%: p = 0.428) between AIA and ATA patients.
CONCLUSIONS
Both focal and diffuse air trappings provide valuable diagnostic information and therefore deserve to be estimated. The lack of significant differences in air trapping and bronchial wall thickness between AIA and ATA patients needs further investigation.
Topics: Adult; Age Factors; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Asthma; Bronchi; Case-Control Studies; Female; Forced Expiratory Volume; Humans; Male; Middle Aged; Prospective Studies; Sex Factors; Tomography, X-Ray Computed
PubMed: 18577849
DOI: 10.1159/000141652 -
European Radiology Jul 2017To compare the parenchymal attenuation change between inspiration/expiration CTs with dynamic ventilation change between xenon wash-in (WI) inspiration and wash-out (WO)... (Comparative Study)
Comparative Study
OBJECTIVES
To compare the parenchymal attenuation change between inspiration/expiration CTs with dynamic ventilation change between xenon wash-in (WI) inspiration and wash-out (WO) expiration CTs.
METHODS
52 prospectively enrolled COPD patients underwent xenon ventilation dual-energy CT during WI and WO periods and pulmonary function tests (PFTs). The parenchymal attenuation parameters (emphysema index (EI), gas-trapping index (GTI) and air-trapping index (ATI)) and xenon ventilation parameters (xenon in WI (Xe-WI), xenon in WO (Xe-WO) and xenon dynamic (Xe-Dyna)) of whole lung and three divided areas (emphysema, hyperinflation and normal) were calculated on virtual non-contrast images and ventilation images. Pearson correlation, linear regression analysis and one-way ANOVA were performed.
RESULTS
EI, GTI and ATI showed a significant correlation with Xe-WI, Xe-WO and Xe-Dyna (EI R = -.744, -.562, -.737; GTI R = -.621, -.442, -.629; ATI R = -.600, -.421, -.610, respectively, p < 0.01). All CT parameters showed significant correlation with PFTs except forced vital capacity (FVC). There was a significant difference in GTI, ATI and Xe-Dyna in each lung area (p < 0.01).
CONCLUSIONS
The parenchymal attenuation change between inspiration/expiration CTs and xenon dynamic change between xenon WI- and WO-CTs correlate significantly. There are alterations in the dynamics of xenon ventilation between areas of emphysema.
KEY POINTS
• The xenon ventilation change correlates with the parenchymal attenuation change. • The xenon ventilation change shows the difference between three lung areas. • The combination of attenuation and xenon can predict more accurate PFTs.
Topics: Administration, Inhalation; Aged; Air; Anesthetics, Inhalation; Exhalation; Female; Humans; Lung; Male; Middle Aged; Prospective Studies; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Radiography, Dual-Energy Scanned Projection; Respiration, Artificial; Respiratory Function Tests; Tomography, X-Ray Computed; Vital Capacity; Xenon
PubMed: 27882425
DOI: 10.1007/s00330-016-4657-z -
Advances in Experimental Medicine and... 2012We reviewed what is known about hearing in birds, including the effects of anthropogenic noise, to speculate on the nature of underwater hearing in diving birds. Taking... (Review)
Review
We reviewed what is known about hearing in birds, including the effects of anthropogenic noise, to speculate on the nature of underwater hearing in diving birds. Taking into consideration changes inhuman hearing underwater, the effects of changes in middle ear pressure on hearing in humans, and the protective effects against acoustic overexposure in birds from changes in middle ear pressure, we suggest that if similar patterns hold for diving birds, they may not hear well underwater. Moreover,the frequency of best hearing sensitivity may shift to frequencies below 2 and 4 kHz. Trapped air may allow the middle ear cavity of birds to function much as the swim bladder functions in fish.Diving birds present important auditory and environmental issues. To resolve these issues properly requires comparative anatomical investigations of the middle and inner ears of diving birds.More importantly, behavioral measures of hearing in diving birds must be conducted both in air and in water. Finally, behavioral studies of these animals in their natural habitats are required to deter-mine whether they use sound underwater for communication, foraging, predator avoidance, or other behaviors.
Topics: Air; Animals; Birds; Hearing; Noise; Water
PubMed: 22278454
DOI: 10.1007/978-1-4419-7311-5_17 -
Journal of Computer Assisted Tomography 2014The purpose of this study was to evaluate the relationship between quantitative computed tomography (CT) parameters of air trapping obtained with inspiratory and...
OBJECTIVE
The purpose of this study was to evaluate the relationship between quantitative computed tomography (CT) parameters of air trapping obtained with inspiratory and expiratory CT and pulmonary function tests (PFTs) in patients with relapsing polychondritis (RP).
MATERIALS AND METHODS
This study included 23 patients with RP who underwent both CT and PFTs. In each patient, the mean lung density (MLD) was obtained by averaging CT attenuation of the lung parenchyma on both inspiratory and expiratory CT. The ratio of expiratory MLD to inspiratory MLD (E/I ratio) was also calculated. Correlations between those quantitative CT measurements and the results of PFTs were evaluated using Spearman rank correlation.
RESULTS
The expiratory MLD and E/I ratio were significantly correlated with forced expiratory volume in 1 second (FEV1) %predicted, ratio of FEV1 to FVC (FEV1/FVC), and the mid expiratory phase of forced expiratory flow (FEF25%-75%) %predicted (expiratory MLD: FEV1 %predicted, r = 0.764, P < 0.0001; FEV1/FVC, r = 0.764, P < 0.0001; FEF25%-75% %predicted, r = 0.674, P < 0.001, respectively; the E/I ratio: FEV1 %predicted, r = -0.689, P < 0.001; FEV1/FVC, r = -0.689, P < 0.001; FEF25%-75% %predicted, r = -0.586, P < 0.01, respectively). The correlation between inspiratory MLD and PFTs did not reach statistical significance.
CONCLUSIONS
In RP patients, air trapping demonstrated on expiratory CT correlated with airway obstruction. This study may assist further refinement of the use of CT as quantitative evaluation for small and large airway obstruction in RP.
Topics: Adolescent; Adult; Aged; Air; Exhalation; Female; Humans; Inhalation; Male; Middle Aged; Polychondritis, Relapsing; Respiratory Function Tests; Retrospective Studies; Spirometry; Tomography, X-Ray Computed; Young Adult
PubMed: 25007341
DOI: 10.1097/RCT.0000000000000130 -
Advances in Colloid and Interface... Sep 2017Bacteria are often discussed as active colloids, self-propelled organisms whose collective motion can be studied in the context of non-equilibrium statistical mechanics.... (Review)
Review
Bacteria are often discussed as active colloids, self-propelled organisms whose collective motion can be studied in the context of non-equilibrium statistical mechanics. In such studies, the behavior of bacteria confined to interfaces or in the proximity of an interface plays an important role. For instance, many studies have probed collective behavior of bacteria in quasi two-dimensional systems such as soap films. Since fluid interfaces can adsorb surfactants and other materials, the stress and velocity boundary conditions at interfaces can alter bacteria motion; hydrodynamic studies of interfaces with differing boundary conditions are reviewed. Also, bacteria in bulk can become trapped at or near fluid interfaces, where they colonize and form structures comprising secretions like exopolysaccharides, surfactants, living and dead bacteria, thereby creating Films of Bacteria at Interfaces (FBI). The formation of FBI is discussed at air-water, oil-water, and water-water interfaces, with an emphasis on film mechanics, and with some allusion to genetic functions guiding bacteria to restructure fluid interfaces. At air-water interfaces, bacteria form pellicles or interfacial biofilms. Studies are reviewed that reveal that pellicle material properties differ for different strains of bacteria, and that pellicle physicochemistry can act as a feedback mechanism to regulate film formation. At oil-water interfaces, a range of FBI form, depending on bacteria strain. Some bacteria-laden interfaces age from an initial active film, with dynamics dominated by motile bacteria, through viscoelastic states, to form an elastic film. Others remain active with no evidence of elastic film formation even at significant interface ages. Finally, bacteria can adhere to and colonize ultra-low surface tension interfaces such as aqueous-aqueous systems common in food industries. Relevant literature is reviewed, and areas of interest for potential application are discussed, ranging from health to bioremediation.
Topics: Air; Bacillus subtilis; Biofilms; Elasticity; Escherichia coli; Industrial Oils; Polysaccharides, Bacterial; Pseudomonas aeruginosa; Surface Properties; Surface-Active Agents; Thermodynamics; Viscosity; Water
PubMed: 28778342
DOI: 10.1016/j.cis.2017.07.016 -
Journal of Chromatography. A Apr 2010Sorbent tubes/traps are widely used in combination with gas chromatographic (GC) analytical methods to monitor the vapour-phase fraction of organic compounds in air.... (Review)
Review
Sorbent tubes/traps are widely used in combination with gas chromatographic (GC) analytical methods to monitor the vapour-phase fraction of organic compounds in air. Applications range from atmospheric research and ambient air monitoring (indoor and outdoor) to occupational hygiene (personal exposure assessment) and measuring chemical emission levels. Part 1 of this paper reviewed the main sorbent-based air sampling strategies including active (pumped) tube monitoring, diffusive (passive) sampling onto sorbent tubes/cartridges plus sorbent trapping/focusing of whole air samples that are either collected in containers (such as canisters or bags) or monitored online. Options for subsequent extraction and transfer to GC(MS) analysis were also summarised and the trend to thermal desorption (TD)-based methods and away from solvent extraction was explained. As a result of this trend, demand for TD-compatible sorbents (alternatives to traditional charcoal) is growing. Part 2 of this paper therefore continues with a summary of TD-compatible sorbents, their respective advantages and limitations and considerations for sorbent selection. Other analytical considerations for optimizing sorbent-based air monitoring methods are also discussed together with recent technical developments and sampling accessories which have extended the application range of sorbent trapping technology generally.
Topics: Absorption; Air; Air Pollutants; Artifacts; Breath Tests; Environmental Monitoring; Humans; Hydrophobic and Hydrophilic Interactions; Particle Size; Temperature; Volatile Organic Compounds
PubMed: 20106482
DOI: 10.1016/j.chroma.2010.01.015 -
The Journal of Asthma : Official... Mar 2006Air trapping is frequently observed during high-resolution computed tomography (HRCT) of patients with asthma, but whether the condition is reversible has not been...
Air trapping is frequently observed during high-resolution computed tomography (HRCT) of patients with asthma, but whether the condition is reversible has not been thoroughly investigated. The aim of the present study was to evaluate reversibility of air trapping in response to bronchodilator. Ten never-smokers with stable asthma enrolled in the study. Spirometry and HRCT were performed before and after bronchodilator inhalation. Air trapping remained unchanged, although significant reversibility of FEV(1) was observed. Air trapping scores correlated significantly with airway wall thickness. These observations suggest that air trapping is irreversible and that it represents structural remodeling of small airways in patients with stable asthma.
Topics: Administration, Inhalation; Adult; Aged; Air; Asthma; Bronchi; Bronchodilator Agents; Female; Forced Expiratory Volume; Humans; Male; Middle Aged; Tomography, X-Ray Computed
PubMed: 16517428
DOI: 10.1080/02770900500498287