The measurement of lung volume is as old as the spirometer. Measurements of lung volume and its s... more The measurement of lung volume is as old as the spirometer. Measurements of lung volume and its subdivisions yield critical diagnostic information about the principle cause of disease, either restrictive with decreased volume or obstructive with increased volume. There are numerous simple and complex techniques for measuring lung volume including simple spirometry, body plethysmography, and the CT scan.
The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Div... more The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Division of Lung Diseases of the National Heart, Lung, and Blood Institute (NHLBI), is the largest outcome study of mild to moderate asthma in children to be undertaken, with eight clinical centers in the United States and Canada participating. The initial recruitment goal was 960 children within an 18-month recruitment period. Recruitment was extended to 23 months, with 1041 children randomized from late December, 1993, to early September, 1995. In this time interval each of the eight centers met the recruitment goal of 120 using a variety of self-selected recruitment strategies. The goal for minority recruiting was 33%, or 320 of the planned 960 children to be recruited. CAMP achieved the overall goal for the number of minorities, with 330 patients. Three centers recruited at or above the expected rate from the beginning. The other five centers had significant delays in recruitment. Examination of the recruitment experiences of the centers with and without delays did not indicate any single recruitment strategy that was certain to be successful. The most commonly cited factors for success were a cohesive staff, endorsement of participation by the child's primary care provider, and ability of the staff to be flexible and honest in assessing progress and the value of recruiting methods being used.
Rationale: Bronchodilator response (BDR) is a measure of improvement in airway smooth muscle tone... more Rationale: Bronchodilator response (BDR) is a measure of improvement in airway smooth muscle tone, inhibition of liquid accumulation and mucus section into the lumen in response to short-acting beta-2 agonists that varies among asthmatic patients. MicroRNAs (miRNAs) are well-known post-translational regulators. Identifying miRNAs associated with BDR could lead to a better understanding of the underlying complex pathophysiology. Objective: The purpose of this study is to identify circulating miRNAs associated with bronchodilator response in asthma and decipher possible mechanism of bronchodilator response variation. Methods: We used available small RNA sequencing on blood serum from 1,134 asthmatic children aged 6 to 14 years who participated in the Genetics of Asthma in Costa Rica Study (GACRS). We ltered the participants into high and low bronchodilator response (BDR) quartiles and used DeSeq2 to identify miRNAs with differential expression (DE) in high (N= 277) vs low (N= 278) BDR group. Replication was carried out in the Leukotriene modi er Or Corticosteroids or Corticosteroid-Salmeterol trial (LOCCS), an adult asthma cohort. The putative target genes of DE miRNAs were identi ed, and pathway enrichment analysis was performed. Results: We identi ed 10 down-regulated miRNAs having odds ratios (OR) between 0.37 and 0.76 for a doubling of miRNA counts and one up-regulated miRNA (OR=2.26) between high and low BDR group. These were assessed for replication in the LOCCS cohort, where two miRNAs (miR-200b-3p and miR-1246) were associated. Further, functional annotation of 11 DE miRNAs were performed as well as of two replicated miRs. Target genes of these miRs were enriched in regulation of cholesterol biosynthesis by SREBPs, ESR-mediated signaling, G1/S transition, RHO GTPase cycle, and signaling by TGFB family pathways. Conclusion: MiRNAs miR-1246 and miR-200b-3p are associated with both childhood and adult asthma BDR. Our ndings add to the growing body of evidence that miRNAs play a signi cant role in the difference of asthma treatment response among patients as it points to genomic regulatory machinery underlying difference in bronchodilator response among patients.
Background and ObjectiveAirway hyperresponsiveness (AHR) is commonly assessed by a methacholine c... more Background and ObjectiveAirway hyperresponsiveness (AHR) is commonly assessed by a methacholine challenge test (MCT), during which a provocative concentration causing a 20% reduction in forced expiratory volume in 1 second (FEV1) (PC20) < 8 mg/ml is considered a positive response. However, a fall in specific airway conductance (sGaw) may also have clinical significance. The purpose of this study was to assess whether AHR determined by a provocative concentration causing a 40% reduction in sGaw (PC40) < 8 mg/ml corresponds to a clinical diagnosis of asthma.MethodsWe analysed the changes in spirometry, lung volumes and sGaw during MCT in 211 randomly selected patients being evaluated for AHR to support a clinical diagnosis of asthma.ResultsThe mean (SD) age of the group was 53 (15) years, with 141 women (67%). Overall lung function was normal, with FEV1 = 92 (15) % predicted, total lung capacity = 97 (13) % predicted and sGaw = 0.19 (0.15–0.23) L/s/cm H2O/L, (median, 25–75 IQR). There were many more patients who responded by PC40 only (n = 120) than who responded by PC20 (n = 52). There was no significant difference in asthma diagnosis between the PC20 (98%) and PC40 (93%) groups, and we estimate 34% of patients with a diagnosis of asthma would have been classified as having no AHR if only the FEV1 criterion was used.ConclusionChanges in sGaw during MCT indicate clinically significant AHR in support of a clinical diagnosis of asthma among patients being evaluated for asthma.
The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Div... more The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Division of Lung Diseases of the National Heart, Lung, and Blood Institute (NHLBI), is the largest outcome study of mild to moderate asthma in children to be undertaken, with eight clinical centers in the United States and Canada participating. The initial recruitment goal was 960 children within an 18-month recruitment period. Recruitment was extended to 23 months, with 1041 children randomized from late December, 1993, to early September, 1995. In this time interval each of the eight centers met the recruitment goal of 120 using a variety of self-selected recruitment strategies. The goal for minority recruiting was 33%, or 320 of the planned 960 children to be recruited. CAMP achieved the overall goal for the number of minorities, with 330 patients. Three centers recruited at or above the expected rate from the beginning. The other five centers had significant delays in recruitment. Examination of the recruitment experiences of the centers with and without delays did not indicate any single recruitment strategy that was certain to be successful. The most commonly cited factors for success were a cohesive staff, endorsement of participation by the child's primary care provider, and ability of the staff to be flexible and honest in assessing progress and the value of recruiting methods being used.
In a secondary analysis of data from a prior study, we calculated the relationships among depress... more In a secondary analysis of data from a prior study, we calculated the relationships among depression (PHQ-8), anxiety (GAD-7), and measures of asthma in 69 steroid-naïve patients with mild and moderate symptomatic asthma. Average levels of pulmonary function, depression and anxiety tended to be in the normal range, and asthma tended to be well controlled (Asthma Control Test). Nevertheless, PHQ-8 scores were significantly correlated with forced oscillation (FO) measures of airway reactance (AX) and resistance at a low frequency of stimulation (Rrs5Hz). GAD-7 scores also were significantly related to Rrs5Hz. Exploratory analyses in supplementary data provide no evidence for vagal mediation of the association. Further research is necessary to discover mechanisms for the associations found here. Future studies might examine the utility of assessing and treating mild anxiety and depression in mild to moderate asthma.
Medicine & Science in Sports & Exercise, 2021
PURPOSE We quantified the magnitude of exercise-induced bronchodilation in adult asthmatics under... more PURPOSE We quantified the magnitude of exercise-induced bronchodilation in adult asthmatics under conditions of narrowed and dilated airways. We then assessed the effect of the bronchodilation on ventilatory capacity and the extent of ventilatory limitation during exercise. METHODS Eleven asthmatics completed three exercise bouts on a cycle ergometer. Exercise was preceded by no treatment (trialCON), inhaled β2-agonist (trialBD), or a eucapnic voluntary hyperpnea challenge (trialBC). Maximal expiratory flow-volume maneuvers (MEFV) were performed before and within 40 seconds of exercise cessation. Exercise tidal flow-volume loops were placed within the pre- and post-exercise MEFV curve and used to determine expiratory flow-limitation (EFL) and maximum ventilatory capacity (V˙ ECap). RESULTS Pre-exercise airway function was different among the trials (forced expiratory volume 1 second [FEV1] during trialCON, trialBD, and trialBC = 3.3 ± 0.8, 3.8 ± 0.8, and 2.9 ± 0.8 L, respectively; P < 0.05). Maximal expired airflow increased with exercise during all three trials, but the increase was greatest during trialBC (delta FEV1 during trialCON, trialBD, and trialBC = +12.2 ± 13.1, +5.2 ± 5.7, +28.1 ± 15.7%). Thus, the extent of EFL decreased, and V˙ ECap increased, when the post-exercise MEFV curve was used. During trialCON and trialBC, actual exercise ventilation exceeded V˙ ECap calculated with the pre-exercise MEFV curve in seven and nine subjects, respectively. CONCLUSION These findings demonstrate the critical importance of exercise bronchodilation in the asthmatic with narrowed airways. Of clinical relevance, the results also highlight the importance of assessing airway function during or immediately after exercise in asthmatic persons; otherwise, mechanical limitations to exercise ventilation will be overestimated.
The Journal of Allergy and Clinical Immunology: In Practice, 2020
BACKGROUND: Biomarkers that can predict loss of asthma control among patients being considered fo... more BACKGROUND: Biomarkers that can predict loss of asthma control among patients being considered for step-down therapy in well-controlled disease are lacking. OBJECTIVE: To evaluate whether baseline biomarkers of type 2 airway inflammation and/or serial measurement of fractional exhaled nitric oxide (FENO) predict loss of asthma control as therapy is stepped down. METHODS: In subanalyses of a multicenter randomized, double-blind, parallel 3-arm trial comparing strategies for step-down therapy in well-controlled asthma (Long-Acting Beta-Agonist
Platelet-activating factor (PAF) increases the bronchoconstrictor response of mammalian airways t... more Platelet-activating factor (PAF) increases the bronchoconstrictor response of mammalian airways to cholinergic agonists and is thus implicated as a potential mediator of airway hyperreactivity. This study further defines the nature of the increase in airway responsiveness induced by PAF. We employed an in situ canine tracheal preparation, which allows differentiation of the effects PAF has on airway smooth muscle contraction from confounding effects it has on inducing airway edema and secretions. We found that PAF, infused regionally into tracheal arteries, increases the responsiveness of the trachealis muscle to parasympathetic stimuli in a dose-dependent manner. This effect occurred within 15 min. To determine whether the increase in trachealis muscle responsiveness resulted from effects localized to the trachea, we compared the effect of PAF on the tracheal segment with effects of the lower airways of the lung. Delivered to the arteries perfusing the tracheal segment, PAF did not...
The Journal of continuing education in the health professions
In an era of competing priorities, funding is increasingly restricted for offices of faculty affa... more In an era of competing priorities, funding is increasingly restricted for offices of faculty affairs and development. Opportunities for professional staff to grow and network through attendance at national meetings and to share best practices are limited. We sought to describe a community of practice established to enhance the professional development of faculty affairs professionals and to document its impact. We outlined the process of formation of the New England Network for Faculty Affairs (NENFA), reviewed the pedagogical approaches to professional development, and surveyed members to evaluate the impact of NENFA on their activities, professional network and their institutions. After a successful 2011 initial meeting, NENFA created an organizing committee and conducted a needs assessment among potential members. NENFA's charter, mission, goals, and structure were based on survey results. NENFA's regional community of practice grew to 31 institutions and held 10 meetings...
Publisher Summary The focus of this chapter is on the pathophysiological presentation of chronic ... more Publisher Summary The focus of this chapter is on the pathophysiological presentation of chronic obstructive pulmonary disease (COPD) and asthma and the features that distinguish each disease as well as the similarities. It also examines the physiological processes that characterize airways disease. In diseases of the airway such as asthma and COPD there are characteristic increases in volume, which distinguish these airway disorders from restrictive processes of the respiratory system that reduce lung volumes. The most useful lung volumes and capacities to measure are those that assess the physical limits of the lung and chest wall and define the extremes of the vital capacity (VC); TLC and RV. Obstructive lung diseases such as chronic bronchitis, asthma, and emphysema all result in increases in lung volume. The physiological mechanisms of asthma and COPD that differ in the details of the inflammatory processes, cells, mediators, and pathology may be very similar physiologically in terms of hyperinflation, loss of static recoil, and expiratory airflow limitation. Bronchodilator responsiveness is also not unique to asthma since patients with COPD often demonstrate reversibility of airflow limitation. Bronchial responsiveness is also present in both entities but the response to bronchoconstrictors is more related to lung function and structure in COPD and the patient with COPD generally does not respond to exercise by exhibiting bronchospasm.
F1000 - Post-publication peer review of the biomedical literature, 2007
Background-Severe asthma causes the majority of asthma morbidity. Understanding mechanisms that c... more Background-Severe asthma causes the majority of asthma morbidity. Understanding mechanisms that contribute to the development of severe disease is important. Objective-The goal of the Severe Asthma Research Program is to identify and characterize subjects with severe asthma to understand pathophysiologic mechanisms in severe asthma.
The measurement of lung volume is as old as the spirometer. Measurements of lung volume and its s... more The measurement of lung volume is as old as the spirometer. Measurements of lung volume and its subdivisions yield critical diagnostic information about the principle cause of disease, either restrictive with decreased volume or obstructive with increased volume. There are numerous simple and complex techniques for measuring lung volume including simple spirometry, body plethysmography, and the CT scan.
The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Div... more The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Division of Lung Diseases of the National Heart, Lung, and Blood Institute (NHLBI), is the largest outcome study of mild to moderate asthma in children to be undertaken, with eight clinical centers in the United States and Canada participating. The initial recruitment goal was 960 children within an 18-month recruitment period. Recruitment was extended to 23 months, with 1041 children randomized from late December, 1993, to early September, 1995. In this time interval each of the eight centers met the recruitment goal of 120 using a variety of self-selected recruitment strategies. The goal for minority recruiting was 33%, or 320 of the planned 960 children to be recruited. CAMP achieved the overall goal for the number of minorities, with 330 patients. Three centers recruited at or above the expected rate from the beginning. The other five centers had significant delays in recruitment. Examination of the recruitment experiences of the centers with and without delays did not indicate any single recruitment strategy that was certain to be successful. The most commonly cited factors for success were a cohesive staff, endorsement of participation by the child's primary care provider, and ability of the staff to be flexible and honest in assessing progress and the value of recruiting methods being used.
Rationale: Bronchodilator response (BDR) is a measure of improvement in airway smooth muscle tone... more Rationale: Bronchodilator response (BDR) is a measure of improvement in airway smooth muscle tone, inhibition of liquid accumulation and mucus section into the lumen in response to short-acting beta-2 agonists that varies among asthmatic patients. MicroRNAs (miRNAs) are well-known post-translational regulators. Identifying miRNAs associated with BDR could lead to a better understanding of the underlying complex pathophysiology. Objective: The purpose of this study is to identify circulating miRNAs associated with bronchodilator response in asthma and decipher possible mechanism of bronchodilator response variation. Methods: We used available small RNA sequencing on blood serum from 1,134 asthmatic children aged 6 to 14 years who participated in the Genetics of Asthma in Costa Rica Study (GACRS). We ltered the participants into high and low bronchodilator response (BDR) quartiles and used DeSeq2 to identify miRNAs with differential expression (DE) in high (N= 277) vs low (N= 278) BDR group. Replication was carried out in the Leukotriene modi er Or Corticosteroids or Corticosteroid-Salmeterol trial (LOCCS), an adult asthma cohort. The putative target genes of DE miRNAs were identi ed, and pathway enrichment analysis was performed. Results: We identi ed 10 down-regulated miRNAs having odds ratios (OR) between 0.37 and 0.76 for a doubling of miRNA counts and one up-regulated miRNA (OR=2.26) between high and low BDR group. These were assessed for replication in the LOCCS cohort, where two miRNAs (miR-200b-3p and miR-1246) were associated. Further, functional annotation of 11 DE miRNAs were performed as well as of two replicated miRs. Target genes of these miRs were enriched in regulation of cholesterol biosynthesis by SREBPs, ESR-mediated signaling, G1/S transition, RHO GTPase cycle, and signaling by TGFB family pathways. Conclusion: MiRNAs miR-1246 and miR-200b-3p are associated with both childhood and adult asthma BDR. Our ndings add to the growing body of evidence that miRNAs play a signi cant role in the difference of asthma treatment response among patients as it points to genomic regulatory machinery underlying difference in bronchodilator response among patients.
Background and ObjectiveAirway hyperresponsiveness (AHR) is commonly assessed by a methacholine c... more Background and ObjectiveAirway hyperresponsiveness (AHR) is commonly assessed by a methacholine challenge test (MCT), during which a provocative concentration causing a 20% reduction in forced expiratory volume in 1 second (FEV1) (PC20) &lt; 8 mg/ml is considered a positive response. However, a fall in specific airway conductance (sGaw) may also have clinical significance. The purpose of this study was to assess whether AHR determined by a provocative concentration causing a 40% reduction in sGaw (PC40) &lt; 8 mg/ml corresponds to a clinical diagnosis of asthma.MethodsWe analysed the changes in spirometry, lung volumes and sGaw during MCT in 211 randomly selected patients being evaluated for AHR to support a clinical diagnosis of asthma.ResultsThe mean (SD) age of the group was 53 (15) years, with 141 women (67%). Overall lung function was normal, with FEV1 = 92 (15) % predicted, total lung capacity = 97 (13) % predicted and sGaw = 0.19 (0.15–0.23) L/s/cm H2O/L, (median, 25–75 IQR). There were many more patients who responded by PC40 only (n = 120) than who responded by PC20 (n = 52). There was no significant difference in asthma diagnosis between the PC20 (98%) and PC40 (93%) groups, and we estimate 34% of patients with a diagnosis of asthma would have been classified as having no AHR if only the FEV1 criterion was used.ConclusionChanges in sGaw during MCT indicate clinically significant AHR in support of a clinical diagnosis of asthma among patients being evaluated for asthma.
The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Div... more The Childhood Asthma Management Program (CAMP), a multicenter clinical trial sponsored by the Division of Lung Diseases of the National Heart, Lung, and Blood Institute (NHLBI), is the largest outcome study of mild to moderate asthma in children to be undertaken, with eight clinical centers in the United States and Canada participating. The initial recruitment goal was 960 children within an 18-month recruitment period. Recruitment was extended to 23 months, with 1041 children randomized from late December, 1993, to early September, 1995. In this time interval each of the eight centers met the recruitment goal of 120 using a variety of self-selected recruitment strategies. The goal for minority recruiting was 33%, or 320 of the planned 960 children to be recruited. CAMP achieved the overall goal for the number of minorities, with 330 patients. Three centers recruited at or above the expected rate from the beginning. The other five centers had significant delays in recruitment. Examination of the recruitment experiences of the centers with and without delays did not indicate any single recruitment strategy that was certain to be successful. The most commonly cited factors for success were a cohesive staff, endorsement of participation by the child&#39;s primary care provider, and ability of the staff to be flexible and honest in assessing progress and the value of recruiting methods being used.
In a secondary analysis of data from a prior study, we calculated the relationships among depress... more In a secondary analysis of data from a prior study, we calculated the relationships among depression (PHQ-8), anxiety (GAD-7), and measures of asthma in 69 steroid-naïve patients with mild and moderate symptomatic asthma. Average levels of pulmonary function, depression and anxiety tended to be in the normal range, and asthma tended to be well controlled (Asthma Control Test). Nevertheless, PHQ-8 scores were significantly correlated with forced oscillation (FO) measures of airway reactance (AX) and resistance at a low frequency of stimulation (Rrs5Hz). GAD-7 scores also were significantly related to Rrs5Hz. Exploratory analyses in supplementary data provide no evidence for vagal mediation of the association. Further research is necessary to discover mechanisms for the associations found here. Future studies might examine the utility of assessing and treating mild anxiety and depression in mild to moderate asthma.
Medicine & Science in Sports & Exercise, 2021
PURPOSE We quantified the magnitude of exercise-induced bronchodilation in adult asthmatics under... more PURPOSE We quantified the magnitude of exercise-induced bronchodilation in adult asthmatics under conditions of narrowed and dilated airways. We then assessed the effect of the bronchodilation on ventilatory capacity and the extent of ventilatory limitation during exercise. METHODS Eleven asthmatics completed three exercise bouts on a cycle ergometer. Exercise was preceded by no treatment (trialCON), inhaled β2-agonist (trialBD), or a eucapnic voluntary hyperpnea challenge (trialBC). Maximal expiratory flow-volume maneuvers (MEFV) were performed before and within 40 seconds of exercise cessation. Exercise tidal flow-volume loops were placed within the pre- and post-exercise MEFV curve and used to determine expiratory flow-limitation (EFL) and maximum ventilatory capacity (V˙ ECap). RESULTS Pre-exercise airway function was different among the trials (forced expiratory volume 1 second [FEV1] during trialCON, trialBD, and trialBC = 3.3 ± 0.8, 3.8 ± 0.8, and 2.9 ± 0.8 L, respectively; P < 0.05). Maximal expired airflow increased with exercise during all three trials, but the increase was greatest during trialBC (delta FEV1 during trialCON, trialBD, and trialBC = +12.2 ± 13.1, +5.2 ± 5.7, +28.1 ± 15.7%). Thus, the extent of EFL decreased, and V˙ ECap increased, when the post-exercise MEFV curve was used. During trialCON and trialBC, actual exercise ventilation exceeded V˙ ECap calculated with the pre-exercise MEFV curve in seven and nine subjects, respectively. CONCLUSION These findings demonstrate the critical importance of exercise bronchodilation in the asthmatic with narrowed airways. Of clinical relevance, the results also highlight the importance of assessing airway function during or immediately after exercise in asthmatic persons; otherwise, mechanical limitations to exercise ventilation will be overestimated.
The Journal of Allergy and Clinical Immunology: In Practice, 2020
BACKGROUND: Biomarkers that can predict loss of asthma control among patients being considered fo... more BACKGROUND: Biomarkers that can predict loss of asthma control among patients being considered for step-down therapy in well-controlled disease are lacking. OBJECTIVE: To evaluate whether baseline biomarkers of type 2 airway inflammation and/or serial measurement of fractional exhaled nitric oxide (FENO) predict loss of asthma control as therapy is stepped down. METHODS: In subanalyses of a multicenter randomized, double-blind, parallel 3-arm trial comparing strategies for step-down therapy in well-controlled asthma (Long-Acting Beta-Agonist
Platelet-activating factor (PAF) increases the bronchoconstrictor response of mammalian airways t... more Platelet-activating factor (PAF) increases the bronchoconstrictor response of mammalian airways to cholinergic agonists and is thus implicated as a potential mediator of airway hyperreactivity. This study further defines the nature of the increase in airway responsiveness induced by PAF. We employed an in situ canine tracheal preparation, which allows differentiation of the effects PAF has on airway smooth muscle contraction from confounding effects it has on inducing airway edema and secretions. We found that PAF, infused regionally into tracheal arteries, increases the responsiveness of the trachealis muscle to parasympathetic stimuli in a dose-dependent manner. This effect occurred within 15 min. To determine whether the increase in trachealis muscle responsiveness resulted from effects localized to the trachea, we compared the effect of PAF on the tracheal segment with effects of the lower airways of the lung. Delivered to the arteries perfusing the tracheal segment, PAF did not...
The Journal of continuing education in the health professions
In an era of competing priorities, funding is increasingly restricted for offices of faculty affa... more In an era of competing priorities, funding is increasingly restricted for offices of faculty affairs and development. Opportunities for professional staff to grow and network through attendance at national meetings and to share best practices are limited. We sought to describe a community of practice established to enhance the professional development of faculty affairs professionals and to document its impact. We outlined the process of formation of the New England Network for Faculty Affairs (NENFA), reviewed the pedagogical approaches to professional development, and surveyed members to evaluate the impact of NENFA on their activities, professional network and their institutions. After a successful 2011 initial meeting, NENFA created an organizing committee and conducted a needs assessment among potential members. NENFA's charter, mission, goals, and structure were based on survey results. NENFA's regional community of practice grew to 31 institutions and held 10 meetings...
Publisher Summary The focus of this chapter is on the pathophysiological presentation of chronic ... more Publisher Summary The focus of this chapter is on the pathophysiological presentation of chronic obstructive pulmonary disease (COPD) and asthma and the features that distinguish each disease as well as the similarities. It also examines the physiological processes that characterize airways disease. In diseases of the airway such as asthma and COPD there are characteristic increases in volume, which distinguish these airway disorders from restrictive processes of the respiratory system that reduce lung volumes. The most useful lung volumes and capacities to measure are those that assess the physical limits of the lung and chest wall and define the extremes of the vital capacity (VC); TLC and RV. Obstructive lung diseases such as chronic bronchitis, asthma, and emphysema all result in increases in lung volume. The physiological mechanisms of asthma and COPD that differ in the details of the inflammatory processes, cells, mediators, and pathology may be very similar physiologically in terms of hyperinflation, loss of static recoil, and expiratory airflow limitation. Bronchodilator responsiveness is also not unique to asthma since patients with COPD often demonstrate reversibility of airflow limitation. Bronchial responsiveness is also present in both entities but the response to bronchoconstrictors is more related to lung function and structure in COPD and the patient with COPD generally does not respond to exercise by exhibiting bronchospasm.
F1000 - Post-publication peer review of the biomedical literature, 2007
Background-Severe asthma causes the majority of asthma morbidity. Understanding mechanisms that c... more Background-Severe asthma causes the majority of asthma morbidity. Understanding mechanisms that contribute to the development of severe disease is important. Objective-The goal of the Severe Asthma Research Program is to identify and characterize subjects with severe asthma to understand pathophysiologic mechanisms in severe asthma.
Uploads
Papers by charles Irvin