Detection of air trapping in chronic obstructive pulmonary disease by low frequency ultrasound

<p>Abstract</p> <p>Background</p> <p>Spirometry is regarded as the gold standard for the diagnosis of COPD, yet the condition is widely underdiagnosed. Therefore, additional screening methods that are easy to perform and to interpret are needed. Recently, we demonstrated that low frequency ultrasound (LFU) may be helpful for monitoring lung diseases. The objective of this study was to evaluate whether LFU can be used to detect air trapping in COPD. In addition, we evaluated the ability of LFU to detect the effects of short-acting bronchodilator medication.</p> <p>Methods</p> <p>Seventeen patients with COPD and 9 healthy subjects were examined by body plethysmography and LFU. Ultrasound frequencies ranging from 1 to 40 kHz were transmitted to the sternum and received at the back during inspiration and expiration. The high pass frequency was determined from the inspiratory and the expiratory signals and their difference termed ΔF. Measurements were repeated after inhalation of salbutamol.</p> <p>Results</p> <p>We found significant differences in ΔF between COPD subjects and healthy subjects. These differences were already significant at GOLD stage 1 and increased with the severity of COPD. Sensitivity for detection of GOLD stage 1 was 83% and for GOLD stages worse than 1 it was 91%. Bronchodilator effects could not be detected reliably.</p> <p>Conclusions</p> <p>We conclude that low frequency ultrasound is cost-effective, easy to perform and suitable for detecting air trapping. It might be useful in screening for COPD.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01080924">NCT01080924</a></p

Observation of Live Ticks (Haemaphysalis flava) by Scanning Electron Microscopy under High Vacuum Pressure

Scanning electron microscopes (SEM), which image sample surfaces by scanning with an electron beam, are widely used for steric observations of resting samples in basic and applied biology. Various conventional methods exist for SEM sample preparation. However, conventional SEM is not a good tool to observe living organisms because of the associated exposure to high vacuum pressure and electron beam radiation. Here we attempted SEM observations of live ticks. During 1.5×10−3 Pa vacuum pressure and electron beam irradiation with accelerated voltages (2–5 kV), many ticks remained alive and moved their legs. After 30-min observation, we removed the ticks from the SEM stage; they could walk actively under atmospheric pressure. When we tested 20 ticks (8 female adults and 12 nymphs), they survived for two days after SEM observation. These results indicate the resistance of ticks against SEM observation. Our second survival test showed that the electron beam, not vacuum conditions, results in tick death. Moreover, we describe the reaction of their legs to electron beam exposure. These findings open the new possibility of SEM observation of living organisms and showed the resistance of living ticks to vacuum condition in SEM. These data also indicate, for the first time, the usefulness of tick as a model system for biology under extreme condition

Is the 6-minute pegboard and ring test valid to evaluate upper limb function in hospitalized patients with acute exacerbation of COPD?

Rosimeire Marcos Felisberto,1 Cassia Fabiane de Barros,1 Kelly Cristina Albanezi Nucci,1 Andre Luis Pereira de Albuquerque,1 Elaine Paulin,2 Christina May Moran de Brito,1 Wellington Pereira Yamaguti1 1Hospital S&iacute;rio-Liban&ecirc;s, S&atilde;o Paulo, SP, Brazil; 2Universidade do Estado de Santa Catarina (UDESC), Florian&oacute;polis, SC, Brazil Background: The 6-minute pegboard and ring test (6-PBRT) is a useful test for assessing the functional capacity of upper limbs in patients with stable COPD. Although 6-PBRT has been validated in stable patients, the possibility of a high floor effect could compromise the validity of the test in the hospital setting. The aim of this study was to verify the convergent validity of 6-PBRT in hospitalized patients with acute exacerbation of COPD (AECOPD). Methods: A cross-sectional study was conducted in a tertiary hospital. Patients who were hospitalized due to AECOPD and healthy elderly participants, voluntarily recruited from the community, were considered for inclusion. All participants underwent a 6-PBRT. Isokinetic evaluation to measure the strength and endurance of elbow flexors and extensors, handgrip strength (HGS), spirometry testing, the modified Pulmonary Functional Status Dyspnea Questionnaire (PFSDQ-M), the COPD assessment test (CAT), and symptoms of dyspnea and fatigue were all measured as comparisons for convergent validity. Good convergent validity was considered if &gt;75% of these hypotheses could be confirmed (correlation coefficient&gt;0.50). Results: A total of 17 patients with AECOPD (70.9&plusmn;5.1&nbsp;years and forced expiratory volume in 1&nbsp;second [FEV1] of 41.8%&plusmn;17.9% of predicted) and 11 healthy elderly subjects were included. The HGS showed a significant strong correlation with 6-PBRT performance (r=0.70; p=0.002). The performance in 6-PBRT presented a significant moderate correlation with elbow flexor torque peak (r=0.52; p=0.03) and elbow extensor torque peak (r=0.61; p=0.01). The total muscular work of the 15 isokinetic contractions of the elbow flexor and extensor muscles showed a significant moderate correlation with the performance in 6-PBRT (r=0.59; p=0.01 and r=0.57; p=0.02, respectively). Concerning the endurance of elbow flexors and extensors, there was a significant moderate correlation with 6-PBRT performance (r=-0.50; p=0.04 and r=-0.51; p=0.03, respectively). In relation to the upper-extremity physical activities of daily living (ADLs) assessed by means of PFSDQ-M, there was a significant moderate correlation of 6-PBRT with three domains: influence of dyspnea on ADLs (r=-0.66; p&lt;0.001), influence of fatigue on ADLs (r=-0.60; p=0.01), and change in ADLs in relation to the period before the disease onset (r=-0.51; p=0.03). The CAT was also correlated with 6-PBRT (r=-0.51; p=0.03). Finally, the performance in 6-PBRT showed a significant moderate correlation with the increase in dyspnea (r=-0.63; p=0.01) and a strong correlation with the increase in fatigue of upper limbs (r=-0.76; p&lt;0.001) in patients with AECOPD. Convergent validity was considered adequate, since 81% from 16 predefined hypotheses were confirmed. There was no correlation between 6-PBRT and patients&rsquo; height. The performance in 6-PBRT was worse in patients with AECOPD compared to healthy elderly individuals (248.7&plusmn;63.0 vs 361.6&plusmn;49.9 number of moved rings; p&lt;0.001). Conclusion: The 6-PBRT is valid for the evaluation of functional capacity of upper limbs in hospitalized patients with AECOPD. Keywords: COPD, exacerbation, skeletal muscle, physical activity, exercise capacit