Introdução: O teste de apneia respiratória tem sido testado e demonstrou ser de utilidade clínica. Objetivos: Determinar o tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos (DVO) e em indivíduos normais e correlacionar os tempos de apneia com os testes de função pulmonar. Métodos: Foi realizado um estudo caso-controle incluindo pacientes com DVO (casos) e um grupo controle, composto por voluntários com espirometria normal, recrutados no Hospital de Clínicas de Porto Alegre (HCPA). A espirometria foi realizada com espirômetro computadorizado e o teste de apneia respiratória utilizando-se um sistema eletrônico microprocessado e um pneumotacógrafo ((Hans Rudolph ® – Kansas OH, EUA)– Kansas OH, EUA) como transdutor de fluxo. As curvas de fluxo respiratório foram exibidas em tempo real em um computador portátil e os tempos máximos de apneia voluntária inspiratória e expiratória (TAVIM e TAVEM) foram determinados a partir do sinal adquirido. Resultados: Um total de 35 pacientes com DVO (casos) e 16 controles foram incluídos no estudo. O TAVIM foi significativamente menor nos casos (22,3 ± 11,8 s) do que no grupo controle (31,5 ± 15,7 s) com p = 0,025. O TAVEM também foi significativamente menor nos casos (16,9 ± 6,6 s) do que no grupo controle (22,1 ± 7,9 s) com p = 0,017. Foram encontradas correlações positivas moderadas entre TAVIM e CVF (r = 0,476, p = 0,004) e entre TAVIM e VEF1 (r = 0,383, p = 0,023). Conclusões: As medidas de TAVIM e TAVEM foram significativamente menores nos casos do que nos controles, e o TAVIM teve correlação moderada com a CVF e VEF1. Estes resultados fornecem uma evidência adicional da utilidade clínica do tempo de apneia como teste de função pulmonar. / Introduction: Breath-holding test has been tested in some clinical scenarios and has proved to be of clinical utility. Objectives: To determine the maximum voluntary breath-holding time in patients with obstructive ventilator defects and in normal subjects and to correlate the breathholding times with pulmonary function tests. Methods: We conducted a case-control study including patients with obstructive ventilator defects and a control group consisted of volunteers recruited in the same hospital, with normal spirometry. Spirometry was performed using a computerized spirometer. The Breath-holding test was conducted using an electronic microprocessor and a (Hans Rudolph ® – Kansas OH, EUA)pneumotachograph and flow transducer. Respiratory flow curves were displayed in real time on a portable computer. The maximal voluntary apnea inspiratory and expiratory times (MVAIT and MVAET) were determined from the acquired signal. Results: A total of 35 patients with obstructive ventilatory defects and 16 controls met the inclusion criteria and were included in the analysis. The MVAIT was lower in cases (22.3 ± 11.8 seconds) than in controls (31.5 ± 15.7 seconds) (p=0.025). MVAET was also lower in cases than in controls (16.9 ± 6.6 vs. 22.1 ± 7.9; p=0.017). We found positive and significant correlations between MVAIT and FVC (L) (r=0.476; p=0.004) and between MVAIT and FEV1 (L) (r=0.383; p=0.023). Conclusions: MVAIT and MVAET were significant lower in patients with obstructive ventilatory defects than in controls, and that MVAIT was correlated positively with FVC and FEV1 in cases. Our results provide additional evidence of usefulness of MVAIT as a pulmonary function test.

Introdução: O teste de apneia respiratória tem sido testado e demonstrou ser de utilidade clínica. Objetivos: Determinar o tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos (DVO) e em indivíduos normais e correlacionar os tempos de apneia com os testes de função pulmonar. Métodos: Foi realizado um estudo caso-controle incluindo pacientes com DVO (casos) e um grupo controle, composto por voluntários com espirometria normal, recrutados no Hospital de Clínicas de Porto Alegre (HCPA). A espirometria foi realizada com espirômetro computadorizado e o teste de apneia respiratória utilizando-se um sistema eletrônico microprocessado e um pneumotacógrafo ((Hans Rudolph ® – Kansas OH, EUA)– Kansas OH, EUA) como transdutor de fluxo. As curvas de fluxo respiratório foram exibidas em tempo real em um computador portátil e os tempos máximos de apneia voluntária inspiratória e expiratória (TAVIM e TAVEM) foram determinados a partir do sinal adquirido. Resultados: Um total de 35 pacientes com DVO (casos) e 16 controles foram incluídos no estudo. O TAVIM foi significativamente menor nos casos (22,3 ± 11,8 s) do que no grupo controle (31,5 ± 15,7 s) com p = 0,025. O TAVEM também foi significativamente menor nos casos (16,9 ± 6,6 s) do que no grupo controle (22,1 ± 7,9 s) com p = 0,017. Foram encontradas correlações positivas moderadas entre TAVIM e CVF (r = 0,476, p = 0,004) e entre TAVIM e VEF1 (r = 0,383, p = 0,023). Conclusões: As medidas de TAVIM e TAVEM foram significativamente menores nos casos do que nos controles, e o TAVIM teve correlação moderada com a CVF e VEF1. Estes resultados fornecem uma evidência adicional da utilidade clínica do tempo de apneia como teste de função pulmonar. / Introduction: Breath-holding test has been tested in some clinical scenarios and has proved to be of clinical utility. Objectives: To determine the maximum voluntary breath-holding time in patients with obstructive ventilator defects and in normal subjects and to correlate the breathholding times with pulmonary function tests. Methods: We conducted a case-control study including patients with obstructive ventilator defects and a control group consisted of volunteers recruited in the same hospital, with normal spirometry. Spirometry was performed using a computerized spirometer. The Breath-holding test was conducted using an electronic microprocessor and a (Hans Rudolph ® – Kansas OH, EUA)pneumotachograph and flow transducer. Respiratory flow curves were displayed in real time on a portable computer. The maximal voluntary apnea inspiratory and expiratory times (MVAIT and MVAET) were determined from the acquired signal. Results: A total of 35 patients with obstructive ventilatory defects and 16 controls met the inclusion criteria and were included in the analysis. The MVAIT was lower in cases (22.3 ± 11.8 seconds) than in controls (31.5 ± 15.7 seconds) (p=0.025). MVAET was also lower in cases than in controls (16.9 ± 6.6 vs. 22.1 ± 7.9; p=0.017). We found positive and significant correlations between MVAIT and FVC (L) (r=0.476; p=0.004) and between MVAIT and FEV1 (L) (r=0.383; p=0.023). Conclusions: MVAIT and MVAET were significant lower in patients with obstructive ventilatory defects than in controls, and that MVAIT was correlated positively with FVC and FEV1 in cases. Our results provide additional evidence of usefulness of MVAIT as a pulmonary function test.

Cystic Fibrosis (CF) is a degenerative disorder that is often associated with chronic lung disease. CF is caused by mutations in the gene encoding the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) chloride channel, which lead to defective chloride and sodium ion movement across epithelia. Subsequent dehydration of the airway surface liquid (ASL) on airway epithelia, is associated with poor mucociliary clearance and chronic lung infection. The monogenic nature of CF, along with the accessibility of the lung, makes the disease amenable to gene replacement therapy. Gene therapy clinical trials have focused on replacing the mutated CFTR with a functional copy, which has led to improved chloride transport, but has shown no significant effects on sodium transport. An alternative strategy for CF gene therapy therefore, could be to reduce the expression of the epithelial sodium channel (ENaC) in the lung, using RNA interference (RNAi), combined with CFTR delivery. Developing a dual-function gene transfer vector could potentially restore chloride and sodium levels in the ASL and help alleviate CF lung disease. The aim of this thesis was to develop a recombinant lentivirus delivery system capable of simultaneously delivering CFTR expression and knocking down ENaC expression in the airways. A modular HIV vector genome plasmid was developed to allow simple insertion of various promoter elements, transgenes and knockdown sequences, for subsequent virus production. Insertion of the CFTR transgene and a short-hairpin RNA (shRNA) sequence targeting the ENaC alpha subunit (ENaCα) resulted in significant knockdown of human ENaCα and simultaneous expression of CFTR in A549 (human lung carcinoma) cell culture. Replacement of the ENaCα shRNA with an shRNA targeting the transcription factor BACH1 resulted in target gene knockdown and concomitant HMOX1 up-regulation, confirming specific knockdown effects, and demonstrating that the dual-function rLV vector could mediate target gene knockdown irrespective of the target. Attempts were made to knock down BACH1 in primary cultures of human bronchial epithelial cells grown at the air-liquid interface (ALI), but improved transduction efficiencies from the apical surface will be required to generate successful knockdown in this experimental model. These studies provide proof-of-principle for the utility of this versatile dual-function prototype virus. The dual function vector not only has the potential for treatment of CF lung disease, but could be readily altered to target other lung diseases where combinations of prolonged target gene knockdown and gene expression/up-regulation could collectively provide an appropriate therapy. In conclusion, the focus on the rational design of gene transfer vectors for specific therapeutic effects will aid the development and translation of gene therapy approaches to human studies.

Chronic Obstructive Pulmonary Disease (COPD) is the 3rd leading cause of death in the US, and idiopathic pulmonary fibrosis (IPF), a type of Interstitial Lung Disease (ILD), is a fast acting, irreversible disease that leads to mortality within 3-5 years. RNA-sequencing provides the opportunity to quantitatively examine the sequences of millions mRNAs, and offers the potential to gain unprecedented insights into the structure of chronic non-malignant lung disease transcriptome. By identifying changes in splicing and novel loci expression associated with disease, we may be able to gain a better understanding of their pathogenesis, identify novel disease-specific biomarkers, and find better targets for therapy. Using RNA-seq data that our group generated on 281 human lung tissue samples (47=Control, 131=COPD, 103=ILD), I initially defined the transcriptomic landscape of lung tissue by identifying which genes were expressed in each tissue sample. I used a mixture model to separate genes into reliable and not reliable expression. Next, I employed reads that overlapped splice junctions in a linear model interaction term to identify disease-specific differential splicing. I identified alternatively spliced genes between control and disease tissues and validated three (PDGFA, NUMB, SCEL) of these genes with qPCR and nanostring (a hybridization-based barcoding technique used to quantify transcripts). Finally, I implemented and improved a pipeline to perform transcriptome assembly using Cufflinks that led to the identification of 1,855 novel loci that did not overlap with UCSC, Vega, and Ensembl annotations. The loci were classified into potential coding and non-coding loci (191 and 1,664, respectively). Expression analysis revealed that there were 120 IPF-associated and 10 emphysema-associated differentially expressed (q < 0.01) novel loci. RNA-seq provides a high-resolution transcript-level view of the pulmonary transcriptome and its modification in lung disease. It has enabled a new understanding of the lung transcriptome structure because it measures not only the transcripts we know but also the ones we do not know. The approaches and improvements I have employed have identified these novel targets and make possible further downstream functional analysis that could identify better targets for therapy and lead to an even better understanding of chronic lung disease pathogenesis. / 2031-01-01T00:00:00Z

Tissues arising late in evolutionary time, such as lung alveoli that are unique to air breathing organisms, have been challenging to generate in vitro from pluripotent stem cells (PSCs), in part because there are limited lower organism model systems available to provide the necessary developmental roadmaps to guide in vitro differentiation. Furthermore, pulmonary alveolar epithelial type II cell (AEC2) dysfunction has been implicated as a primary cause of pathogenesis in many poorly understood lung diseases that lack effective therapies, including interstitial lung disease (ILD) and emphysema. Here we report the successful directed differentiation in vitro of human PSCs into AEC2s, the facultative progenitors of lung alveoli. Using gene editing to engineer multicolored fluorescent reporter PSC lines (NKX2-1GFP;SFTPCtdTomato), we track and purify human SFTPC+ alveolar progenitors as they emerge from NKX2-1+ endodermal developmental precursors in response to stimulation of Wnt and FGF signaling. Purified PSC-derived SFTPC+ cells are able to form monolayered epithelial spheres (“alveolospheres”) in 3D cultures without the need for mesenchymal co-culture support, exhibit extensive self-renewal capacity, and display additional canonical AEC2 functional capacities, including innate immune responsiveness, the production of lamellar bodies able to package surfactant, and the ability to undergo squamous cell differentiation while upregulating type 1 alveolar cell markers. Guided by time-series global transcriptomic profiling we find that AEC2 maturation involves downregulation of Wnt signaling activity, and the highest differentially expressed transcripts in the resulting SFTPC+ cells encode genes associated with lamellar body and surfactant biogenesis. Finally, we apply this novel model system to generate patient-specific AEC2s from induced PSCs (iPSCs) carrying homozygous surfactant mutations (SFTPB121ins2), and we employ footprint-free CRISPR-based gene editing to observe that correction of this genetic lesion restores surfactant processing in the cells responsible for their disease. Thus we provide an approach for disease modeling and future functional regeneration of a cell type unique to air-breathing organisms.

No description available.

Thesis (PhD (Medicine. Internal medicine))--University of Stellenbosch, 2007. / 1.1. Background Tumors arising from the lung, pleura, or chest wall are a frequent problem in clinical pulmonary medicine. Most lesions are either infectious, neoplastic or granulomatous in nature, but a variety of other differential diagnoses must be considered. An accurate diagnosis is important because the available treatments differ substantially, and because any delay will impair the prognosis in potentially curable patients with lung carcinoma. The investigations involve the disciplines of radiology, pulmonology, surgery, microbiology, and anatomical pathology and consume a respectable amount of resources. The aim of the work covered in this thesis was to optimize the available diagnostic methods for the routine use in a health care setting with limited resources. 1.2. Methods The general idea of this work was to identify conventional sampling methods that could be developed further to become more useful for the diagnosis of chest tumors in a low resource health care setting. The key method was research performed: a) to revise and expand the indication for a sampling method, b) to technically improve the sampling process, and c) to optimize sample transport, preparation and analysis in collaboration with the analytical laboratory. 1.3. Results A list of invasive diagnostic procedures, imaging methods and analytical processes were developed, evaluated and integrated into clinical practice. A) transbronchial needle aspiration, B) transthoracic cutting needle biopsy, C) transthoracic fine needle aspiration, D) transthoracic ultrasound, and E) rapid on-site evaluation of needle aspirates by a cytopathologist. Five studies pertaining to this thesis were published in international peerreviewed journals: â ¢ Safety and yield of ultrasound-assisted transthoracic biopsy performed by pulmonologists (Respiration 2004;71:519-22) This paper established that ultrasound-assisted transthoracic biopsy performed by pulmonologists is feasible, safe, practical, low-cost and has a high yield. â ¢ Utility of rapid on-site evaluation of transbronchial needle aspirates (Respiration 2005;72:182-8) This paper demonstrated the economical advantages of on-site evaluation of transbronchial specimens in a low-resource setting. â ¢ Transbronchial needle aspirates: comparison of two preparation methods (Chest 2005;127:2015-8) This paper demonstrated that preparing smears on-site has a far better yield than pooling samples into a vial. This means that the yield is improved over the current standard at no additional cost. â ¢ Transbronchial needle aspirates: how many passes per target site? (European Respiratory Journal 2007;29:112-6) This paper investigated the most economical and effective approach to serial sampling with transbronchial needle aspiration during flexible bronchoscopy. â ¢ Ultrasound assisted transthoracic biopsy: fine needle aspiration or cutting needle biopsy? (European Respiratory Journal 2007;29:357-62) This paper compared two common methods of sampling and demonstrates that the less expensive method is sufficient in the majority of cases. 1.4. Conclusion This work has impacted on current practice in multiple ways. Conventional methods have been optimized by improving technical factors and with the integration of interdisciplinary collaboration. The initiated research is ongoing with the aim to achieve continued technical and economical improvements in the diagnosis of chest tumors.

Radon gas may be a major air quality hazard issue inside the home. Radon (222Rn) comes from the natural breakdown of radioactive uranium (238U) via radium (226Ra) in soil, rocks, and water. Radon and its progeny contribute more than 50% of the total radiation dose to the human population due to inhalation; it can result in severe and fatal lung disease. This investigation has determined the radon concentrations in seventy-seven domestic houses in a mountainous area of Hamadan in Iran which were monitored using track-etch detectors of type CR-39 exposed for three month periods. The arithmetic mean radon concentration in Hamadan buildings was determined to be 80 Bqm-3 and also an average indoor annual effective dose equivalent for the Hamadan city population was calculated as 1.5 mSv. Maximum radon concentrations were noted during the winter and spring season. In addition to this, 28 water wells were monitored by utilizing a Sarad Doseman detector at hourly intervals over extended periods. Radon measurements were also carried out in the nearby Alisadr show cave, using Solid State Nuclear Track etch Detectors (SSNTDs) during the winter and the spring periods. In the cave, the average annual effective geometric and arithmetic mean dose for guides was 28.1 and 34.2 mSv respectively. The dose received by visitors was very low. Hamadan city is built on alluvial fan deposits which are the source of the local water supply. The data from the wells shows that the groundwater in these alluvial deposits influences the flux of radon. The atmospheric radon concentration measurement in wells above the water surface ranged from 1,000 Bqm-3 to 36,600 Bqm-3. There is evidence that radon-rich ground waters play a significant role in the transport of radon through the alluvial fan system. There is evidence that the radon concentrations in homes in Hamadan are greatly influenced by the porous nature of the underlying geology and the movement of groundwater within the alluvial fan.

O objetivo deste estudo foi avaliar as medidas de volume e densidade pulmonar em exames de tomografia computadorizada de alta resolução (TCAR) de tórax de pacientes com esclerose sistêmica (ES), antes e após o transplante de medula óssea (TMO). As medidas foram comparadas com a avaliação funcional e resposta ao tratamento. Este foi um estudo retrospectivo observacional. A avaliação clínica e tomográfica foi realizada antes, após 6 e 18 meses do TMO, dos pacientes com ES que realizaram o procedimento entre 2011 e 2017. A análise quantitativa da TCAR foi feita utilizando programa totalmente automatizado (Yacta), capaz de obter o volume pulmonar, a densidade pulmonar média e os percentis de atenuação (P10, P40, P50, P80 e P90). Os dados clínicos, incluindo o resultado das espirometrias, foram obtidos dos prontuários eletrônicos dos pacientes. A capacidade vital forçada (CVF) aos 18 meses foi utilizada para classificar os pacientes em grupo \"melhor resposta\" (aumento >= 10% dos valores da CVF) ou \"resposta estável\" (redução, estabilidade ou aumento < 10% na CVF). Nenhum paciente apresentou redução da CVF > 10% pós-TMO. Foram incluídos 33 pacientes, com alteração tomográfica ou da função pulmonar antes da realização do TMO. O grupo \"melhor resposta\" foi composto por 15 pacientes (45,4%, 4 homens, idade média de 32,1 anos), enquanto o grupo \"resposta estável\" por 18 pacientes (54,6%, 4 homens, idade média de 37,5 anos). A análise quantitativa das TCAR não demonstrou diferença significativa entre os grupos na fase pré-TMO. No grupo \"melhor resposta\" houve redução significativa da densidade pulmonar média e dos valores dos percentis de densidade após o TMO, destacando-se os percentis 80 e 90. No grupo \"resposta estável\" não houve alteração significativa pós-TMO nos valores de volumes e densidades pulmonares. Concluímos que a análise quantitativa automática da TCAR de pacientes com ES foi capaz de identificar redução significativa da densidadepulmonar nos pacientes com melhora significativa da função pulmonar. Inferimos que, além dos volumes e densidades médias, podem ser utilizados também os percentis de densidade como parâmetro no acompanhamento da doença intersticial. Esta ferramenta pode representar um biomarcador na avaliação de tratamento da doença intersticial pulmonar na ES, complementando as provas de função pulmonar. / The purpose of this study was to evaluate pulmonary volume and density measurements in high resolution computed tomography (HRCT) scans of patients with systemic sclerosis (SSc) before and after bone marrow transplantation (BMT). Measurements were compared with functional assessment and response to treatment. This was a retrospective observational study. Clinical and tomographic evaluation of patients was performed before, after 6 and 18 months of BMT, for patients submitted to the procedure between 2011 and 2017. The quantitative analysis of HRCT scans was performed using a fully automated program (Yacta), capable of obtaining lung volume, density and attenuation percentiles (P10, P40, P50, P80 and P90). Clinical data, including the results of spirometry, were obtained from patients\' electronic records. Forced vital capacity (FVC) at 18 months was used to classify patients into \"best response\" group (>= 10% increase in FVC values) or \"stable response\" (reduction, stability or FVC increase < 10%). No patient had FVC reduction > 10% after BMT. Thirty-three patients were included, with tomographic or pulmonary function alterations before the BMT. The \"best response\" group consisted of 15 patients (45.4%, 4 men, mean age 32.1 years), while the \"stable response\" group comprised 18 patients (54.6%, 4 men, mean age of 37.5 years). Quantitative analysis of HRCT did not show a significant difference between the groups in the pre-BMT evaluation. In the \"best response\" group there was a significant reduction in mean lung density and density percentile values after BMT, with emphasis on the 80th and 90th percentiles. In the \"stable response\" group there was no significant post-BMT change in lung volumes and pulmonary densities. We conclude that the quantitative automatic HRCT analysis of patients with ES identified a significant reduction in pulmonary density in patients with improved pulmonary function. We speculate that, in addition to the mean volumes and densities, density percentiles may also be used as a parameter in the follow-up ofpatients with interstitial lung disease. This tool may represent a biomarker in the evaluation of interstitial lung disease treatment in patients with SSc, complementing pulmonary function tests.

O teste de exercício cardiopulmonar (TECP) (ou teste ergoespirométrico) é considerado o padrão-ouro para avaliação da potência aeróbia, contudo este teste demanda equipamentos sofisticados e profissionais especializados. O interesse pelo teste do degrau para avaliação da capacidade física em indivíduos com doenças pulmonares crônicas cresceu nos últimos anos devido à sua portabilidade. Entretanto, o uso do teste do degrau incremental (TDIM) para avaliação da capacidade física de indivíduos com asma permanece desconhecido. O objetivo deste estudo foi avaliar as respostas cardiopulmonares e metabólicas durante o TDIM em indivíduos com asma moderada a grave bem como avaliar sua reprodutibilidade nesta população. Cinquenta e quatro indivíduos com asma moderada a grave foram submetidos ao TECP e a dois TDIM em ordem aleatorizada. Os testes foram realizados em 2 dias não consecutivos com intervalo mínimo de 48 horas. No primeiro dia, os indivíduos realizaram avaliação do controle clínico da asma pelo Asthma Control Questionnaire (ACQ) e o teste TECP ou os 2 TDIM, de acordo com a aleatorização. Na segunda visita, os indivíduos foram submetidos aos 2 TDIM ou ao TECP de acordo com a aleatorização. Os dados dos pacientes foram analisados em subgrupos de acordo com o índice de massa corpórea (IMC) e divididos em eutróficos, sobrepeso e obesos. O desempenho no melhor TDIM (m-TDIM) foi comparado à resposta do TECP. Os valores de consumo de oxigênio no pico do exercício (VO2pico) obtidos no m-TDIM foram inferiores ao TECP (2.042±494; 1.749±434 ml/min, média±DP, respectivamente; p=0,01). Os limites de concordância do VO2pico entre o m-TDIM e TECP variaram de -786 a 201 ml/min. Não foi observada diferença nos indivíduos eutróficos com asma (EA) na maioria das variáveis analisadas, exceto no coeficiente respiratório (RER). Por outro lado, foi verificado que a maioria das variáveis obtidas no TDIM foram inferiores nos indivíduos com sobrepeso e obeso comparado ao TECP. Apesar dos valores inferiores observados no m-TDIM quando comparado ao TECP na análise com todos os indivíduos, o TDIM se mostrou reprodutível e apresentou um excelente coeficiente de correlação intraclasse para o número de degraus (0,88[0,79 - 0,93]), o VO2pico (0,93[0,88 - 0,96]) e a frequência cardíaca máxima (0,86 [0,76 - 0,92]). Os nossos resultados mostram que o TDIM induz a uma menor resposta do VO2 pico quando comparado ao TECP em indivíduos com asma moderada a grave independente do IMC. Contudo, o TDIM foi bem tolerado e reprodutível nesta população / The cardiopulmonary exercise test (CPET) is the gold standard to measure aerobic fitness; however, CPET is expensive and requires specialized equipment and a qualified operator. There is a growing interest in using step tests to assess exercise capacity in subjects with chronic lung diseases due to its portability. However, the use of modified incremental step test (MIST) to evaluate exercise capacity in subjects with asthma remains unknown. This study aims to evaluate cardiopulmonary and metabolic responses during MIST in adults with moderate to severe asthma. In addition, we investigated the reliability of the MIST in this population. Fifty-four adults with asthma performed a CPET and two MIST with pulmonary gas analysis on two separate days in a randomized order. The tests were performed in 2 non-consecutive days with a minimum interval of 48 hours. On the first day was evaluated the clinical control of asthma by the Asthma Control Questionnaire (ACQ) and the TECP or 2 TDIM, according to the randomization. At the second visit, the subjects were submitted to 2 TDIM or TECP according to the randomization. The subjects were allocated according to BMI (body mass index) in eutrophic, overweight and obese. The best MIST (b-MIST) was considered at the peak of the exercise for comparison with CPET. There was a difference in peak oxygen uptake (VO2peak) assessed by the CPET and the b-MIST (2,042±494; 1,749±434 ml/min, mean ± SD, respectively; p=0.01). The limits of agreement for VO2peak between the CEPT and the b-MIST with ranged from -786 to 201ml/min. MIST was reproducible and presented an excellent intraclass correlation coefficient (CCI [95% confidence interval]) for the number of steps (0.88[0.79 - 0.93]), VO2 (0.93[0.88 - 0.96]) and maximal heart rate (0.86 [0.76 - 0.92]). The MIST elicits a lower VO2peak than the CPET in subjects with moderate to severe asthma regardless the BMI. However, the MIST is well tolerated and reproducible in this population