Adam Wanner

Comparison of the anticholinergic bronchodilator ipratropium bromide with metaproterenol in chronic obstructive pulmonary disease: A 90-day multi-center study

The short- and long-term efficacy and safety of an inhaled quaternary ammonium anticholinergic agent, ipratropium bromide, and a beta agonist aerosol, metaproterenol, were compared in 261 nonatopic patients with chronic obstructive pulmonary disease (COPD). The study was a randomized, double-blind, 90-day, parallel-group trial. On three test days-one, 45, and 90-mean peak responses for forced expiratory volume in one second and forced vital capacity and mean area under the time-response curve were higher for ipratropium than for metaproterenol. Clinical improvement was noted in both treatment groups, especially during the first treatment month, with persistence of improvement throughout the remainder of the study. Side effects were relatively infrequent and generally mild; tremor, a complication of beta agonists, was not reported by any subject receiving ipratropium. These results support the effectiveness and safety of long-term treatment with inhaled ipratropium in COPD.

Effects of chemical mediators of anaphylaxis on ciliary function

We assessed the effects of selected chemical mediators of anaphylaxis on CBF in vitro. Ciliated epithelial cells were obtained from the trachea of conscious sheep with a cytology brush and suspended in a perfusion chamber containing KH. Ciliary activity was viewed microscopically and recorded on videotape for subsequent slow-motion analysis of CBF. Prostaglandin E1 (10(-8) M to 10(-6) M), prostaglandin E2 (10(-10) M to 10(-6) M), and leukotriene-C4 (10(-8) M) increased CBF between 7% and 33%. Histamine caused ciliostimulation only at the relatively high concentrations above 10(-5) M (7% increase in CBF), whereas prostaglandin F2 alpha (10(-10) M and 10(-6) M) was without effect. In no preparation was ciliary discoordination observed. These findings indicate that several chemical mediators of anaphylaxis stimulate CBF and that the previously described impairment of mucociliary transport in stable allergic asthma or antigen-induced bronchoconstriction is probably not caused by a primary alteration of ciliary function.

Initial evaluation of the effects of aerosolized Florida red tide toxins (brevetoxins) in persons with asthma

Florida red tides annually occur in the Gulf of Mexico, resulting from blooms of the marine dinoflagellate Karenia brevis. K. brevis produces highly potent natural polyether toxins, known as brevetoxins, that activate voltage-sensitive sodium channels. In experimental animals, brevetoxins cause significant bronchoconstriction. A study of persons who visited the beach recreationally found a significant increase in self-reported respiratory symptoms after exposure to aerosolized Florida red tides. Anecdotal reports indicate that persons with underlying respiratory diseases may be particularly susceptible to adverse health effects from these aerosolized toxins. Fifty-nine persons with physician-diagnosed asthma were evaluated for 1 hr before and after going to the beach on days with and without Florida red tide. Study participants were evaluated with a brief symptom questionnaire, nose and throat swabs, and spirometry approved by the National Institute for Occupational Safety and Health. Environmental monitoring, water and air sampling (i.e., K. brevis, brevetoxins, and particulate size distribution), and personal monitoring (for toxins) were performed. Brevetoxin concentrations were measured by liquid chromatography mass spectrometry, high-performance liquid chromatography, and a newly developed brevetoxin enzyme-linked immunosorbent assay. Participants were significantly more likely to report respiratory symptoms after Florida red tide exposure. Participants demonstrated small but statistically significant decreases in forced expiratory volume in 1 sec, forced expiratory flow between 25 and 75%, and peak expiratory flow after exposure, particularly those regularly using asthma medications. Similar evaluation during nonexposure periods did not significantly differ. This is the first study to show objectively measurable adverse health effects from exposure to aerosolized Florida red tide toxins in persons with asthma. Future studies will examine the possible chronic effects of these toxins among persons with asthma and other chronic respiratory impairment.

Occupational exposure to aerosolized brevetoxins during Florida red tide events: Effects on a healthy worker population

Karenia brevis (formerly Gymnodinium breve) is a marine dinoflagellate responsible for red tides that form in the Gulf of Mexico. K. brevis produces brevetoxins, the potent toxins that cause neurotoxic shellfish poisoning. There is also limited information describing human health effects from environmental exposures to brevetoxins. Our objective was to examine the impact of inhaling aerosolized brevetoxins during red tide events on self-reported symptoms and pulmonary function. We recruited a group of 28 healthy lifeguards who are occupationally exposed to red tide toxins during their daily work-related activities. They performed spirometry tests and reported symptoms before and after their 8-hr shifts during a time when there was no red tide (unexposed period) and again when there was a red tide (exposed period). We also examined how mild exercise affected the reported symptoms and spirometry tests during unexposed and exposed periods with a subgroup of the same lifeguards. Environmental sampling (K. brevis cell concentrations in seawater and brevetoxin concentrations in seawater and air) was used to confirm unexposed/exposed status. Compared with unexposed periods, the group of lifeguards reported more upper respiratory symptoms during the exposed periods. We did not observe any impact of exposure to aerosolized brevetoxins, with or without mild exercise, on pulmonary function.

Comparative bronchial vasoconstrictive efficacy of inhaled glucocorticosteroids

The vasoconstrictive efficacies of glucocorticosteroids (GS) are usually compared by the McKenzie skin-blanching test and taken as an index of relative potency. The rationale for the present study was to transpose the McKenzie test to the airway and to compare the airway vascular effects of three inhaled GS: beclomethasone dipropionate (BDP), fluticasone propionate (FP) and budesonide (BUD), in healthy subjects and patients with mild stable asthma. A soluble, inert gas-uptake method was used to measure airway blood flow (Qaw). Baseline mean±sd Qaw normalised for anatomical dead space was 53.1±1.4 µL·min−1·mL−1 in healthy subjects (n=10) and 67.8±3 µL·min−1·mL−1 in asthmatics (n=10). All GS caused a transient decrease in Qaw. The magnitude of the vasoconstriction was greater in asthmatics. The relative vasoconstrictive effect of BDP, FP and BUD was 1, 1.9, and 2.7, respectively, in asthmatics and 1, 3.3 and 3.0, respectively, in healthy subjects, as assessed by the dose required to decrease Qaw by 20% from the baseline, 30-min postdrug inhalation. Therefore, measuring airway blood flow may be a useful, site-specific parameter to assess the tissue bioavailability and vasoconstrictive efficacy of inhaled glucocorticosteroids.

Effects of methylxanthines on airway mucociliary function

Mucociliary interaction and hence mucus clearance in the airways is governed by ciliary activity and the depth and rheologic properties of periciliary fluid and mucus. Therefore, a defect in one or more of these component functions must be responsible for the impairment of mucociliary clearance in patients with a variety of airway diseases. Methylxanthines stimulate ciliary beat frequency, augment net ion secretion with a substantial increase in water flux toward the lumen, and promote mucus secretion in the lower airways. The net result is an enhancement of mucociliary clearance. This beneficial action of methylxanthines on mucociliary function may complement their effects on bronchoconstriction and respiratory muscle dysfunction in patients with chronic bronchitis, cystic fibrosis, and bronchial asthma.

Parental self-efficacy and morbidity in pediatric asthma.

This study investigated the relationship between parental self-efficacy and asthma-related morbidity. Participants included 139 parents of children (ages 5–8) who were diagnosed with asthma and were primarily from lower-income and minority backgrounds. Parents completed a 22-item measure of self-efficacy; factor analysis was conducted on this measure, yielding two factors: learned helplessness and self-efficacy. Correlational analyses indicated that higher scores on the learned helplessness factor were significantly related to increased asthma-related morbidity for the majority of morbidity variables. The self-efficacy factor was significantly related to days of school missed. Regression analyses conducted with the factor scores and the morbidity variables provide further support that the learned helplessness factor accounts for a significant amount of the variance in asthma morbidity for many of the variables studied, while the self-efficacy factor was related to only a few. Although improving health outcomes of children with asthma is a multifaceted process, the results of this study suggest that targeting parental self-efficacy, particularly with parents who are experiencing high levels of perceived learned helplessness, may be a helpful component of an intervention program with this population.

Genome-wide study of percent emphysema on computed tomography in the general population. The Multi-Ethnic Study of Atherosclerosis Lung/SNP Health Association Resource Study

RATIONALE Pulmonary emphysema overlaps partially with spirometrically defined chronic obstructive pulmonary disease and is heritable, with moderately high familial clustering. OBJECTIVES To complete a genome-wide association study (GWAS) for the percentage of emphysema-like lung on computed tomography in the Multi-Ethnic Study of Atherosclerosis (MESA) Lung/SNP Health Association Resource (SHARe) Study, a large, population-based cohort in the United States. METHODS We determined percent emphysema and upper-lower lobe ratio in emphysema defined by lung regions less than -950 HU on cardiac scans. Genetic analyses were reported combined across four race/ethnic groups: non-Hispanic white (n = 2,587), African American (n = 2,510), Hispanic (n = 2,113), and Chinese (n = 704) and stratified by race and ethnicity. MEASUREMENTS AND MAIN RESULTS Among 7,914 participants, we identified regions at genome-wide significance for percent emphysema in or near SNRPF (rs7957346; P = 2.2 × 10(-8)) and PPT2 (rs10947233; P = 3.2 × 10(-8)), both of which replicated in an additional 6,023 individuals of European ancestry. Both single-nucleotide polymorphisms were previously implicated as genes influencing lung function, and analyses including lung function revealed independent associations for percent emphysema. Among Hispanics, we identified a genetic locus for upper-lower lobe ratio near the α-mannosidase-related gene MAN2B1 (rs10411619; P = 1.1 × 10(-9); minor allele frequency [MAF], 4.4%). Among Chinese, we identified single-nucleotide polymorphisms associated with upper-lower lobe ratio near DHX15 (rs7698250; P = 1.8 × 10(-10); MAF, 2.7%) and MGAT5B (rs7221059; P = 2.7 × 10(-8); MAF, 2.6%), which acts on α-linked mannose. Among African Americans, a locus near a third α-mannosidase-related gene, MAN1C1 (rs12130495; P = 9.9 × 10(-6); MAF, 13.3%) was associated with percent emphysema. CONCLUSIONS Our results suggest that some genes previously identified as influencing lung function are independently associated with emphysema rather than lung function, and that genes related to α-mannosidase may influence risk of emphysema.

Effect of ipratropium bromide on airway mucociliary function

Airway mucociliary dysfunction leading to a depression of mucus transport has been demonstrated in patients with acute and chronic bronchitis, cystic fibrosis, and bronchial asthma; use of bronchodilators that might further impair mucociliary function, therefore, generally has been discouraged. Atropine and ipratropium bromide are cholinergic antagonists that are effective bronchodilators in various clinical settings. Atropine has been shown to block the production of respiratory secretions in response to cholinergic stimulation, but to have no effect on baseline secretions. Atropine has also been clearly demonstrated to depress ciliary beat frequency and to slow airway mucociliary clearance, whereas the short-term and long-term administration of ipratropium bromide at higher than clinically recommended doses seems to lack these effects. No satisfactory explanation has thus far been offered for this difference between the two cholinergic antagonists. Nevertheless, with respect to airway mucociliary function, ipratropium bromide appears to be preferable to atropine in the treatment of obstructive airways disease.

The role of mucociliary dysfunction in bronchial asthma.

Abnormalities of mucociliary function in the airways of patients with bronchial asthma are suggested by the clinical observation of excessive tracheobronchial secretions which are difficult to expectorate and may contribute to bronchial obstruction. Pathologic and functional studies in animals and patients have demonstrated an impairment of mucociliary transport mechanisms, but the pathogenesis of this abnormality is still poorly understood. In patients with allergic asthma, the elaboration of chemical mediators in the lung seems to depress mucociliary function. Although pharmacologic agents which increase mucous transport rates have been identified, more potent stimulators will probably be needed to produce a clinical improvement in patients with bronchial asthma.