Comparison of the ATS versus EU Mini Wright peak flow meter in normal volunteers

OBJECTIVES

The American Thoracic Society (ATS) and European Union (EU) have precise and accurate Mini Wright peak flow meters. The purpose of this investigation was to compare both 1) for accuracy using a pneumotachometer, 2) in volunteers to determine whether they are interchangeable, and 3) to spirometrically predicted peak flows.

METHODS

Lab testing: A pneumotachometer was connected in series with each peak flow meter and varying flows pushed through both meters for comparison. Human subjects: Nonsmoking adult volunteers did three standing peak flows. The order of peak flow meter used was random. The best of three efforts was used for analysis. The t-test, concordance correlation coefficient (CCC), Deming regression, and Bland-Altman plot were the analytic strategies used to determine agreement. Peak flow results were compared to spirometrically predicted values.

RESULTS

Fifty-seven volunteers, average age 37 ± 12 years and mean BMI 24.9 ± 2.5 years, were included. The average peak flows were different at 541 ± 114 and 526 ± 112 L/min for the ATS and EU meters, respectively (p < .01). Both peak flow meter values were significantly different than spirometrically predicted values of 483 ± 86 L/min (p < .01). The CCC was 0.98 (0.97-0.99) and regression revealed a slope and y-intercept consistent with 1 and 0, respectively. The Bland-Altman plot revealed no increase in scatter of values over the range of peak flows versus the difference with a mean bias of 15 ± 15 L/min. Laboratory testing revealed that the ATS and EU peak flow meters read 3.0 ± 2.1% above and -2.0 ± 1.5% below the comparison pneumotachometer, respectively. The pneumotachometer comparison was significantly different for both meters at p < .01, paired t-test.

CONCLUSIONS

The ATS peak flow meter reads 2.8% higher than the EU peak flow meter across a range of flows. Both meters have similar accuracy with a different bias compared with a pneumotachometer. Finally, both peak flow meters read slightly and significantly higher than spirometrically derived peak flows. Therefore, the peak flow meters are not interchangeable and both may obtain slightly higher values than those determined using current spirometrically derived prediction equations.

Tiotropium bromide step-up therapy for adults with uncontrolled asthma

BACKGROUND

Long-acting beta-agonist (LABA) therapy improves symptoms in patients whose asthma is poorly controlled by an inhaled glucocorticoid alone. Alternative treatments for adults with uncontrolled asthma are needed.

METHODS

In a three-way, double-blind, triple-dummy crossover trial involving 210 patients with asthma, we evaluated the addition of tiotropium bromide (a long-acting anticholinergic agent approved for the treatment of chronic obstructive pulmonary disease but not asthma) to an inhaled glucocorticoid, as compared with a doubling of the dose of the inhaled glucocorticoid (primary superiority comparison) or the addition of the LABA salmeterol (secondary noninferiority comparison).

RESULTS

The use of tiotropium resulted in a superior primary outcome, as compared with a doubling of the dose of an inhaled glucocorticoid, as assessed by measuring the morning peak expiratory flow (PEF), with a mean difference of 25.8 liters per minute (P<0.001) and superiority in most secondary outcomes, including evening PEF, with a difference of 35.3 liters per minute (P<0.001); the proportion of asthma-control days, with a difference of 0.079 (P=0.01); the forced expiratory volume in 1 second (FEV1) before bronchodilation, with a difference of 0.10 liters (P=0.004); and daily symptom scores, with a difference of -0.11 points (P<0.001). The addition of tiotropium was also noninferior to the addition of salmeterol for all assessed outcomes and increased the prebronchodilator FEV1 more than did salmeterol, with a difference of 0.11 liters (P=0.003).

CONCLUSIONS

When added to an inhaled glucocorticoid, tiotropium improved symptoms and lung function in patients with inadequately controlled asthma. Its effects appeared to be equivalent to those with the addition of salmeterol. (Funded by the National Heart, Lung, and Blood Institute; ClinicalTrials.gov number, NCT00565266.).

A trial of clarithromycin for the treatment of suboptimally controlled asthma

BACKGROUND

PCR studies have demonstrated evidence of Mycoplasma pneumoniae and Chlamydophila pneumoniae in the lower airways of patients with asthma.

OBJECTIVE

To test the hypothesis that clarithromycin would improve asthma control in individuals with mild-to-moderate persistent asthma that was not well controlled despite treatment with low-dose inhaled corticosteroids.

METHODS

Adults with an Asthma Control Questionnaire score ≥1.5 after a 4-week period of treatment with fluticasone propionate were entered into a PCR-stratified randomized, controlled trial to evaluate the effect of 16 weeks of either clarithromycin or placebo, added to fluticasone, on asthma control in individuals with or without lower airway PCR evidence of M pneumoniae or C pneumoniae.

RESULTS

A total of 92 participants were randomized. Twelve (13%) subjects demonstrated PCR evidence of M pneumoniae or C pneumoniae in endobronchial biopsies; 80 were PCR-negative for both organisms. In PCR-positive participants, clarithromycin yielded a 0.4 ± 0.4 unit improvement in the Asthma Control Questionnaire score, with a 0.1 ± 0.3 unit improvement in those allocated to placebo. This between-group difference of 0.3 ± 0.5 (P = .6) was neither clinically nor statistically significant. In PCR-negative participants, a nonsignificant between-group difference of 0.2 ± 0.2 units (P = .3) was observed. Clarithromycin did not improve lung function or airway inflammation but did improve airway hyperresponsiveness, increasing the methacholine PC(20) by 1.2 ± 0.5 doubling doses (P = .02) in the study population.

CONCLUSION

Adding clarithromycin to fluticasone in adults with mild-to-moderate persistent asthma that was suboptimally controlled by low-dose inhaled corticosteroids alone did not further improve asthma control. Although there was an improvement in airway hyperresponsiveness with clarithromycin, this benefit was not accompanied by improvements in other secondary outcomes.

Urinary leukotriene E4/exhaled nitric oxide ratio and montelukast response in childhood asthma

BACKGROUND

A subset of children with asthma respond better to leukotriene receptor antagonists than to inhaled corticosteroids. Information is needed to identify children with these preferential responses.

OBJECTIVE

We sought to determine whether the ratio of urinary leukotriene E(4) (LTE(4)) to fractional exhaled nitric oxide (FE(NO)) delineates children with preferential responsiveness to montelukast compared with fluticasone propionate (FP) therapy.

METHODS

Data from 318 children with mild-to-moderate asthma enrolled in 2 National Heart, Lung, and Blood Institute Childhood Asthma Research and Education Network studies (Characterizing the Response to a Leukotriene Receptor Antagonist and an Inhaled Corticosteroid [CLIC] and the Pediatric Asthma Controller Trial [PACT]) were analyzed. The association between LTE(4)/FE(NO) ratios at baseline and improved lung function or asthma control days (ACDs) with montelukast and FP therapy was determined, and phenotypic characteristics related to high ratios were assessed.

RESULTS

LTE(4)/FE(NO) ratios were associated with a greater response to montelukast than FP therapy for FEV(1) measurements (2.1% increase per doubling of ratio, P = .001) and for ACDs per week (0.3-ACD increase, P = .009) in the CLIC study. In PACT the ratio was associated with greater ACD responsiveness to MT than FP therapy (0.6 ACD increase, P=.03) [corrected]. In a combined study analysis, LTE(4): FE(NO) ratios were associated with greater response to MT than FP therapy for FEV(1) (1.8% increase, P =.0005) and ACDs (0.4 increase, P =.001)[corrected].Children with LTE(4)/FE(NO) ratios at or above the 75th percentile were likely (P < .05) to be younger and female and exhibit lower levels of atopic markers and methacholine reactivity.

CONCLUSION

LTE(4)/FE(NO) ratios predict a better response to montelukast than FP therapy in children with mild-to-moderate asthma.

The assessment, serial evaluation, and subsequent sequelae of acute kidney injury (ASSESS-AKI) study: design and methods

Background

The incidence of acute kidney injury (AKI) has been increasing over time and is associated with a high risk of short-term death. Previous studies on hospital-acquired AKI have important methodological limitations, especially their retrospective study designs and limited ability to control for potential confounding factors.

Methods

The Assessment, Serial Evaluation, and Subsequent Sequelae of Acute Kidney Injury (ASSESS-AKI) Study was established to examine how a hospitalized episode of AKI independently affects the risk of chronic kidney disease development and progression, cardiovascular events, death, and other important patient-centered outcomes. This prospective study will enroll a cohort of 1100 adult participants with a broad range of AKI and matched hospitalized participants without AKI at three Clinical Research Centers, as well as 100 children undergoing cardiac surgery at three Clinical Research Centers. Participants will be followed for up to four years, and will undergo serial evaluation during the index hospitalization, at three months post-hospitalization, and at annual clinic visits, with telephone interviews occurring during the intervening six-month intervals. Biospecimens will be collected at each visit, along with information on lifestyle behaviors, quality of life and functional status, cognitive function, receipt of therapies, interim renal and cardiovascular events, electrocardiography and urinalysis.

Conclusions

ASSESS-AKI will characterize the short-term and long-term natural history of AKI, evaluate the incremental utility of novel blood and urine biomarkers to refine the diagnosis and prognosis of AKI, and identify a subset of high-risk patients who could be targeted for future clinical trials to improve outcomes after AKI.

Effect of the tyrosine kinase inhibitors (sunitinib, sorafenib, dasatinib, and imatinib) on blood glucose levels in diabetic and nondiabetic patients in general clinical practice

Tyrosine kinase is a key enzyme activity utilized in many intracellular messaging pathways. Understanding the role of particular tyrosine kinases in malignancies has allowed for the design of tyrosine kinase inhibitors (TKIs), which can target these enzymes and interfere with downstream signaling. TKIs have proven to be successful in the treatment of chronic myeloid leukemia, renal cell carcinoma and gastrointestinal stromal tumor, and other malignancies. Scattered reports have suggested that these agents appear to affect blood glucose (BG). We retrospectively studied the BG concentrations in diabetic (17) and nondiabetic (61) patients treated with dasatinib (8), imatinib (39), sorafenib (23), and sunitinib (30) in our clinical practice. Mean declines of BG were dasatinib (53 mg/dL), imatinib (9 mg/dL), sorafenib (12 mg/dL), and sunitinib (14 mg/dL). All these declines in BG were statistically significant. Of note, 47% (8/17) of the patients with diabetes were able to discontinue their medications, including insulin in some patients. Only one diabetic patient developed symptomatic hypoglycemia while on sunitinib. The mechanism for the hypoglycemic effect of these drugs is unclear, but of the four agents tested, c-kit and PDGFRβ are the common target kinases. Clinicians should keep the potential hypoglycemic effects of these agents in mind; modification of hypoglycemic agents may be required in diabetic patients. These results also suggest that inhibition of a tyrosine kinase, be it c-kit, PDGFRβ or some other undefined target, may improve diabetes mellitus BG control and it deserves further study as a potential novel therapeutic option.

Forced expiratory flow between 25% and 75% of vital capacity and FEV1/forced vital capacity ratio in relation to clinical and physiological parameters in asthmatic children with normal FEV1 values

BACKGROUND

The assumption that the assessment of forced expiratory flow between 25% and 75% of vital capacity (FEF(25-75)) does not provide additional information in asthmatic children with normal FEV(1) percent predicted has not been adequately tested.

OBJECTIVE

We sought to determine whether the measurement of FEF(25-75) percent predicted offers advantages over FEV(1) percent predicted and FEV(1)/forced vital capacity (FVC) percent predicted for the evaluation of childhood asthma.

METHODS

This is a secondary analysis of data from the Pediatric Asthma Controller Trial and the Characterizing the Response to a Leukotriene Receptor Antagonist and Inhaled Corticosteroid trials. Pearson correlation coefficients, Pearson partial correlation coefficients, canonical correlations, and receiver operating characteristic (ROC) curves were constructed.

RESULTS

Among 437 children with normal FEV(1) percent predicted, FEF(25-75) percent predicted, and FEV(1)/FVC percent predicted were (1) positively correlated with log(2) methacholine PC(20), (2) positively correlated with morning and evening peak expiratory flow percent predicted, and (3) negatively correlated with log(10) fraction of exhaled nitric oxide and bronchodilator responsiveness. Pearson partial correlations and canonical correlations indicated that FEF(25-75) percent predicted was better correlated with bronchodilator responsiveness and log(2) methacholine PC(20) than were FEV(1) percent predicted or FEV(1)/FVC percent predicted. In the ROC curve analysis, FEF(25-75) at 65% of predicted value had a 90% sensitivity and a 67% specificity for detecting a 20% increase in FEV(1) after albuterol inhalation.

CONCLUSION

FEF(25-75) percent predicted was well correlated with bronchodilator responsiveness in asthmatic children with normal FEV(1). FEF(25-75) percent predicted should be evaluated in clinical studies of asthma in children and might be of use in predicting the presence of clinically relevant reversible airflow obstruction.

Dual-platform proteomics study of plasma biomarkers in pediatric patients undergoing cardiopulmonary bypass

Plasma samples from pediatric cardiac patients undergoing cardiopulmonary bypass (CPB) procedures were used to identify and characterize patterns of changes in potential biomarkers related to tissue damage and inflammation. These included proteins associated with systemic inflammatory response syndrome. Potential biomarkers were identified using a dual-platform proteomics approach requiring approximately 150 microL of plasma, which included two-dimensional difference gel electrophoresis (2D-DIGE) and a multiplexed immunoassay. Methods used in the dual approach measured levels of 129 proteins in plasma from pediatric CPB patients. Of these, 70 proteins changed significantly (p<0.05) between time points, and 36 of these retained significance after the highly stringent Bonferroni correction [p<0.001 for 2D-DIGE and p<0.00056 for multianalyte profile (MAP) assays]. Many of the changing proteins were associated with tissue damage, inflammation, and oxidative stress. This study uses a novel approach that combines two discovery proteomics techniques to identify a pattern of potential biomarkers changing after CPB. This approach required only 150 microL of plasma per time point and provided quantitative information on 129 proteins. The changes in levels of expression of these proteins may provide insight into the understanding, treatment, and prevention of systemic inflammation, thereby helping to improve the outcomes of pediatric CPB patients.

Primary cell lines: false representation or model system? a comparison of four human colorectal tumors and their coordinately established cell lines

Cultured cell lines have played an integral role in the study of tumor biology since the early 1900's. The purpose of this study is to evaluate colorectal cancer (CRC) cell lines with respect to progenitor tumors and assess whether these cells accurately and reliably represent the cancers from which they are derived. Primary cancer cell lines were derived from fresh CRC tissue. Tumorigenicity of cell lines was assessed by subcutaneous injection of cells into athymic mice and calculation of tumor volume after 3 weeks. DNA ploidy was evaluated by flow cytometry. Invasive ability of the lines was tested with the MATRIGEL invasion assay at 24 or 48 hours. Cells were assessed for the presence of Kirsten-Ras (K-Ras), p-53, deleted in colon cancer (DCC), and Src. Protein profiling of cells and tissue was performed by surface enhanced laser desorption/ionization-time of flight/mass spectroscopy. microRNA expression in cell and tumor tissue samples was evaluated by FlexmiR MicroRNA Assays. Four cell lines were generated from tumor tissue from patients with CRC and confirmed to be tumorigenic (mean tumor volume 158.46 mm(3)). Two cell lines were noted to be diploid; two were aneuploid. All cell lines invaded the MATRIGEL starting as early as 24 hours. K-Ras, p53, DCC, and Src expression were markedly different between cell lines and corresponding tissue. Protein profiling yielded weak-to-moderate correlations between cell samples and respective tissues of origin. Weak-to-moderate tau correlations for levels of expression of human microRNAs were found between cells and respective tissue samples for each of the four pairings. Although our primary CRC cell lines vary in their expression of several tumor markers and known microRNAs from their respective progenitor tumor tissue, they do not statistically differ in overall profiles. Characteristics are retained that deem these cell lines appropriate models of disease; however, data acquired through the use of cell culture may not always be a completely reliable representation of tumor activity in vivo.

Effect of beta2-adrenergic receptor polymorphism on response to longacting beta2 agonist in asthma (LARGE trial): a genotype-stratified, randomised, placebo-controlled, crossover trial

BACKGROUND

Some studies suggest that patients with asthma who are homozygous for arginine at the 16th amino acid position of the beta2-adrenergic receptor (B16 Arg/Arg) benefit less from treatment with longacting beta2 agonists and inhaled corticosteroids than do those homozygous for glycine (B16 Gly/Gly). We investigated whether there is a genotype-specific response to treatment with a longacting beta2 agonist in combination with inhaled corticosteroid.

METHODS

In this multicentre, randomised, double-blind, placebo-controlled trial, adult patients with moderate asthma were enrolled in pairs matched for forced expiratory volume in 1 s and ethnic origin, according to whether they had the B16 Arg/Arg (n=42) or B16 Gly/Gly (n=45) genotype. Individuals in a matched pair were randomly assigned by computer-generated randomisation sequence to receive inhaled longacting beta2 agonist (salmeterol 50 microg twice a day) or placebo given in a double-blind, crossover design for two 18-week periods. Open-label inhaled corticosteroid (hydrofluoroalkane beclometasone 240 microg twice a day) was given to all participants during the treatment periods. The primary endpoint was morning peak expiratory flow (PEF). Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00200967.

FINDINGS

After 18 weeks of treatment, mean morning PEF in Arg/Arg participants was 21.4 L/min (95% CI 11.8-31.1) higher when participants were assigned to receive salmeterol than when assigned to receive placebo (p<0.0001). In Gly/Gly participants, morning PEF was 21.5 L/min (11.0-32.1) higher when participants were assigned to receive salmeterol than when assigned to receive placebo (p<0.0001). The improvement in PEF did not differ between genotypes (difference [Arg/Arg-Gly/Gly] -0.1, -14.4 to 14.2; p=0.99). In Gly/Gly participants, methacholine PC20 (20% reduction in forced expiratory volume in 1 s; a prespecified secondary outcome) was 2.4 times higher when participants were assigned to salmeterol than when assigned to placebo (p<0.0001). Responsiveness to methacholine did not differ between salmeterol and placebo in Arg/Arg participants (p=0.87). The 2.5 times higher genotype-specific difference in responsiveness to methacholine was significant (1.32 doubling dose difference between genotypes, 0.43-2.21, p=0.0038). Seven Arg/Arg participants (placebo, n=5; salmeterol, n=2) and six Gly/Gly participants (placebo, n=3; salmeterol, n=3) had an asthma exacerbation. Five serious adverse events were reported, one each during the pre-match and run-in phases on open-label inhaled corticosteroid, two during double-blind treatment with salmeterol/inhaled corticosteroid, and one during double-blind treatment with placebo/inhaled corticosteroid. None of the serious events was asthma-related or related to study drugs or procedures.

INTERPRETATION

In asthma patients with B16 Arg/Arg and B16 Gly/Gly genotypes, combination treatment with salmeterol and inhaled corticosteroid improved airway function when compared with inhaled corticosteroid therapy alone. These findings suggest that patients should continue to be treated with longacting beta2 agonists plus moderate-dose inhaled corticosteroids irrespective of B16 genotype. Further investigation is needed to establish the importance of the genotype-specific difference in responsiveness to methacholine.

FUNDING

National Institutes of Health.

Proxy healthcare decision-making for persons with intellectual disability: perspectives of residential-agency directors

Directors of residential agencies for persons with intellectual disability in one U.S. state completed a self-administered, mailed survey to assess relative importance of information sources and decision factors in proxy healthcare decision-making. The most important sources were physician recommendations and input from the person; family input, care staff recommendations, and medical records were less valued. The person's wishes and best interests and recommendations of medical experts were the most important decision factors. Less important were benefits and risks of the intervention, family wishes, and health status; little emphasis was accorded to religious affiliation and extra cost to agency. More research is needed on how best to elicit the wishes and determine what constitutes the "best interests" of these vulnerable individuals.

Peak expiratory flow in normals: comparison of the mini Wright versus spirometric predicted peak flows

OBJECTIVES

U.S. prediction equation estimated peak flows were obtained spirometrically and may not correctly predict actual peak flows that are obtained using a peak flow meter. The purpose of this investigation was to compare actual Mini Wright peak flows in normal volunteers as compared with spirometric predicted values to determine whether they are similar.

METHODS

Nonsmoking, nonobese adult volunteers with no history of lung disease underwent peak flow testing with an American Thoracic Society (ATS) Mini Wright peak flow meter. All subjects did three peak flows by taking a maximal deep breath and expiring as hard and fast as possible while in the standing position. The best of three efforts was taken as the peak flow value for analysis and compared with prediction equation estimates. The paired t test compared differences between actual and predicted values. The concordance correlation coefficient evaluated whether the actual peak flows were interchangeable with predicted.

RESULTS

Seventy-two volunteers, average age 44 +/- 10 years and mean BMI 25.2 +/- 2.9, were included. The Mini Wright peak flow values of 508 +/- 113 L/min were significantly different than the predicted values of 471 +/- 84 (p < 0.01). The predicted values were reduced on average by 7.3 percent compared to actual values. The concordance correlation coefficient was 0.72 (95% C.I.; 0.60 - 0.80) suggesting the actual and predicted values are not interchangeable.

CONCLUSIONS

The ATS Mini Wright peak flow values are slightly higher than spirometrically derived predicted peak flow values in subjects without lung disease. This suggests that predicted peak flow values should be generated by a peak flow meter and would be higher than current spirometrically predicted values.

Development and validation of the hand assessment tool

The objective was to develop a self-administered activity limitation measurement tool for individuals with hand and wrist injuries, and to evaluate the reliability and validity of the new instrument, the Hand Assessment Tool (HAT). The final version of the HAT instrument, the SF12, and Disabilities of Arm, Shoulder, and Hand Questionnaire (DASH) were given to 94 consecutive new hand surgery clinic patients. Statistical analyses indicated excellent internal consistency with Cronbach's alpha of 0.91. Test-retest reliability of the HAT showed a concordance correlation coefficient of 0.73, with 95% confidence interval=(0.60, 0.83). Excellent correlation between the HAT and DASH was noted. A modest agreement with the SF12 physical score was observed. The HAT correlated well with the DASH and SF12 physical score and proved to be an internally consistent and reliable instrument for evaluation of activity limitations for individuals who sustain wrist or hand injury.

A content analysis from a US statewide survey of memorable healthcare decisions for individuals with intellectual disability

BACKGROUND

Little is known about surrogate healthcare decision-making for individuals with intellectual disability (ID). This study examined healthcare decision-making by residential-agency directors to learn their process and the extent to which the individual is included.

METHOD

Content analysis of qualitative data from a mailed survey of residential-agency directors in a large US northeastern state.

RESULTS

Narrative comments of 102 directors (65% of respondents) are reported. Three themes emerged: (a) Identifying someone else's "best interest" is challenging; (b) Perceptions of the healthcare community, especially related to quality of life, can influence care provided; and (c) Surrogate decision-making is a team effort.

CONCLUSIONS

With knowledge of how decisions are made, the healthcare community can better interact with the complex array of service agencies and persons who determine care for this vulnerable population.

Signs and symptoms that precede wheezing in children with a pattern of moderate-to-severe intermittent wheezing

OBJECTIVES

To examine parent-reported signs and symptoms as antecedents of wheezing in preschool children with previous moderate to severe wheezing episodes, and to determine the predictive capacity of these symptom patterns for wheezing events.

STUDY DESIGN

Parents (n = 238) of children age 12 to 59 months with moderate-to-severe intermittent wheezing enrolled in a year-long clinical trial completed surveys that captured signs and symptoms at the start of a respiratory tract illness (RTI). Sensitivity, specificity, negative predictive value, and positive predictive value (PPV) for each symptom leading to wheezing during that RTI were calculated.

RESULTS

The most commonly reported first symptom categories during the first RTI were "nose symptoms" (41%), "significant cough" (29%), and "insignificant cough" (13%). The most reliable predictor of subsequent wheezing was significant cough, which had a specificity of 78% and a PPV of 74% for predicting wheezing.

CONCLUSIONS

Significant cough is the most reliable antecedent of wheezing during an RTI. It may be useful to consider individualized symptom patterns as a component of management plans intended to minimize wheezing episodes.

The concordance correlation coefficient for repeated measures estimated by variance components

The concordance correlation coefficient (CCC) is an index that is commonly used to assess the degree of agreement between observers on measuring a continuous characteristic. Here, a CCC for longitudinal repeated measurements is developed through the appropriate specification of the intraclass correlation coefficient from a variance components linear mixed model. A case example and the results of a simulation study are provided.

Interaction of ambient air pollution with asthma medication on exhaled nitric oxide among asthmatics

The interaction between ambient air pollution and asthma medication remains unclear. The authors compared airway inflammation response to air pollution among asthmatics. Increases of 10 ppb of nitrogen dioxide (NO2) and of 10 microg/m3 of particulate matter < 10 micron in diameter (PM10) daily concentrations were associated with an increase in exhaled nitric oxide (eNO) of 0.13 ppb (95% confidence interval = 0.06, 0.19) and of 0.07 ppb (95% confidence interval = 0.02, 0.12), respectively, in models adjusted for important covariates. The results show that the medication could not counteract airway inflammation effects of air pollution. Specifically, the patients on triamcinolone decreased the sensitivity to PM10 but increased the sensitivity to NO2. The patients on salmeterol were more vulnerable to both NO2 and PM10. This study indicates that the current pollution levels may still enhance airway inflammation among patients with persistent asthma even when they are on asthma medications.

Associations between air pollution and peak expiratory flow among patients with persistent asthma

Responses of patients with persistent asthma to ambient air pollution may be different from those of general populations. For example, asthma medications may modify the effects of ambient air pollutants on peak expiratory flow (PEF). Few studies examined the association between air pollution and PEF in patients with persistent asthma on well-defined medication regimens using asthma clinical trial data. Airway obstruction effects of ambient air pollutants, using 14,919 person-days of daily self-measured peak expiratory flow (PEF), were assessed from 154 patients with persistent asthma during the 16 wk of active treatment in the Salmeterol Off Corticosteroids Study trial. The three therapies were an inhaled corticosteroid, an inhaled long-acting beta-agonist, and placebo. The participants were nonsmokers aged 12 through 63 yr, recruited from 6 university-based ambulatory care centers from February 1997 to January 1999. Air pollution data were derived from the U.S. Environmental Protection Agency Aerometric Information Retrieval System. An increase of 10 ppb of ambient daily mean concentrations of NO2 was associated with a decrease in PEF of 1.53 L/min (95% confidence interval [CI] -2.93 to -0.14) in models adjusted for age, gender, race/ethnicity, asthma clinical center, season, week, daily average temperature, and daily average relative humidity. The strongest association between NO2 and PEF was observed among the patients treated with salmeterol. Negative associations were also found between PEF and SO2 and between PEF and PM(10), respectively. The results show that the two medication regimens protected against the effects of PM(10). However, salmeterol increased the sensitivity to NO2 and triamcinalone enhanced the sensitivity to SO2.

Age-related changes in the expression and oxidation of bronchoalveolar lavage proteins in the rat

The incidence and severity of many lung diseases change with age. Some diseases, such as pneumonia, occur with increased frequency in children and the elderly. Proteins obtained by bronchoalveolar lavage (BAL) serve as the first line of defense against inhaled toxins and pathogens. Age-related changes in BAL protein expression and oxidative modification were examined in juvenile (1 mo), young adult (2 mo), and aged (18 mo) F344 rats using two-dimensional difference gel electrophoresis (2D-DIGE), matrix-assisted laser desorption ionization-time of flight/time of flight (MALDI-ToF/ToF) tandem mass spectrometry, and carbonyl immunoblotting. Using 2D-DIGE, we detected 563 protein spots, and MALDI-ToF/ToF identified 204 spots comprising 31 proteins; 21 changed significantly (17 increases) between juvenile and young adult or aged rats, but for 12 of these proteins, levels had a biphasic pattern, and levels in aged rats were less than in young adults. Relative carbonylation was determined by comparison of immunostaining with total protein staining on each oxidized protein blot. We found that aged rats had significantly increased oxidation in 13 proteins compared with juvenile rats. Many of the proteins altered in expression or oxidation level had functions in host defense, redox regulation, and protein metabolism. We speculate that low levels of expression of host defense proteins in juvenile rats and decreases in levels of these proteins between young adult and aged rats may predispose these groups to pneumonia. In addition, we have shown age-related increases in protein oxidation that may compromise host defense function in aged rats.