An unsuccessful attempt to instrumentally condition peak expiratory flow rates in asthmatic children.
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Asthma↗
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Extended preservation of the ischemic canine lung by ventilation with PEEP.
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Animals↗
Pulmonary function studies: aid to diagnosis for dyspnea.
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Asthma↗
The sequence of lobar emptying in man.
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Adult↗
Patterns of bulbar respiratory neurons during and after artifical hyperventilation.
Single bulbar respiratory unit activity was recorded in urethane-anesthetized rabbits. During artificial ventilation, reflex contractions of the diaphragm were elicited by the forced deflations of the respirator. Out of 44 neurons, four I, one E and two EI units exhibited a shift of their discharge relative to the contractile phase of the diaphragm, compared to normal respiration. During hypocapnic apnea, some I, IE and E neurons became silent. Other cells belonging to all phase types, however, continued to fire tonically at a rate less than the peak rate in normal bursts. When rhythmic respiration resumed after termination of the apneic pause, five (I, IE and E) units exhibited a transient phase shift of their burst discharge compared to normal respiration. The results of simultaneous recordings of two neurons belonging to different phase types are compatible with the assumption that inspiratory units are periodically inhibited by inspiratory-expiratory cells.
Animals↗
Separation and characterisation of formaldehydrogenic delta-4-3-oxo-C21-steroids by means of thin-layer chromatography on silica gel.
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Acetates↗
Efficacy of troleandomycin in outpatients with severe, corticosteroid-dependent asthma.
Sixteen severe, corticosteroid-dependent yet resistant outpatient asthmatics were treated with troleandomycin (TAO), a macrolide antibiotic, in an attempt to both induce a clinical remission and reduce methylprednisolone requirements. Within the first 2 wk of initiating TAO therapy, 50% of the patients experienced a greater than 20% increase in forced expiratory volume in 1 sec (FEV1) and 80% noted a greater than 20% increase in forced vital capacity between 25% and 75% (FVC 25%-75%). Maximal increases in FEV1 and FVC 25%-75% were noted in all patients within the first 6 wk on TAO and methylprednisolone. There was a concomitant clinical improvement in all patients. Corticosteroid-induced side effects, gastrointestinal tract discomfort, and elevated serum glutamic pyruvic transaminase (SGPT) were common yet generally transient during TAO and methylprednisolone therapy. After a 4- to 18-mo follow-up 15/16 patients were well-controlled on TAO and methylprednisolone. Methylprednisolone requirements were reduced at least four- to fivefold in most patients during TAO therapy. Normal morning serum cortisol levels were documented after varying intervals in most patients when both TAO (250 mg) and methylprednisolone (4 to 16 mg) could be reduced to alternate-day administration. Only one patient was forced to discontinue therapy due to side effects. The present study extends the effectiveness of TAO therapy to ambulatory asthmatics, establishes a clinical strategy that maximizes benefit/risk factors, and provides practical guidelines for the long-term use of TAO and methylprednisolone.
Adolescent↗
Magnitude and site of airway response to exercise in asthmatics in relation to arterial histamine levels.
In order to determine if there is a relationship among arterial histamine levels, state of disease activity, and the magnitude and site of obstruction in exercise-induced asthma, we recorded airway resistance, lung volumes, spirometry, and density dependence of maximum expiratory flow before and after an exercise challenge in 17 asymptomatic individuals. These observations were then related to the concentration of histamine in systemic arterial blood. This study demonstrates that those individuals whose disease process was the most active at the time of investigation had more depressed lung function and higher baseline histamine levels, and responded to the challenge with severe obstruction that involved the airways in the periphery of the lung. In contrast, those subjects whose underlying disease was more quiescent had lower histamine values and the response to provocation was less severe and predominated in the larger airways. In neither group did the postchallenge values for histamine increase. It is suggested that the factor that determines these patterns of response is the state of inflammation of the airways, for which histamine may serve as a marker.
Adult↗
Airway response to inhaled histamine in asymptomatic long-term marijuana smokers.
Bronchial challenge with histamine was used to assess bronchial reactivity in asymptomatic individuals who were long-term social smokers of marijuana. Their reactivity was compared to that of nonsmokers and asthmatics. Spirometry results were normal in the marijuana users. There was no significant difference in bronchial reactivity between marijuana smokers and nonsmoking controls, whereas the asthmatics demonstrated the expected hyperreactivity. These observations suggest that customary social use of marijuana may not produce abnormalities in airway function detectable by spirometry or bronchoprovocation.
Administration, Intranasal↗
Bronchial hyperreactivity to methacholine in farmers' lung disease.
Methacholine inhalation challenges were performed in five groups: 14 patients with history of farmers' lung disease (FLD), nine well farmers with precipitating antibodies to Micropolyspora faeni antigen, II normal subjects, 12 asthmatic patients, and 10 patients with interstitial lung disease (ILD) other than hypersensitivity pneumonitis. After calculating the mean areas under the dose-response curves, FLD patients had a significantly greater degree of methacholine sensitivity than did well farmers with M. faeni antibody and normals. However, the methacholine sensitivity of FLD patients was indistinguishable from a group of patients with ILD and significantly less than the asthmatic group. Fifty percent of patients with FLD had positive methacholine challenges (greater than or equal to 20% decrease in their 1-sec forced vital capacity [FEV1] from the control FEV1). Hyperirritable airways was a common finding in FLD.
Antibodies, Fungal↗
Airway responsiveness to histamine as a test for overall severity of asthma in children.
Seventy-eight children who had a history of asthma were studied while they were symptom-free. There was a highly significant correlation between the dose of aerosolized histamine that produced a decrease in FEV1 of 20% and each of the features in the history that indicated severity of asthma. The correlation was strengthened by the combination of these features into a weighted asthma history score. None of the subjects with mildly increased bronchial reactivity had a history score of severe asthma, and none with markedly increased bronchial reactivity had mild asthma. There was also a highly significant correlation between histamine dose and the results of spirometric tests for airway obstruction. However, the correlation between asthma history score and provocative histamine dose was highly significant even in the 21 subjects who were apparently free of airway obstruction at the time of testing. Furthermore, the correlation between asthma history score and histamine dose was stronger than that between asthma score and any spirometric test, indicating that the histamine test more accurately assessed the overall severity of the asthma. Measurement of bronchial responsiveness to histamine is a useful adjunct to history in determining the severity of asthma in an individual and should be considered as an objective way of grading subjects according to severity of asthma in a clinical study.
Adolescent↗
An improved protocol for the use of troleandomycin (TAO) in the treatment of steroid-requiring asthma.
An improved protocol was developed for the use of troleandomycin (TAO) in severe, steroid-requiring subjects with asthma. Compared to previous reports, this protocol uses a lower starting dose of TAO and a rapid steroid taper. Fifteen patients were treated with TAO following the new guidelines. Steroid requirements in the 15 patients dropped by 68% within 2 weeks, and 13 of the 15 patients were able to be maintained on alternate day steroids. In spite of rapid steroid taper, both FEV1 and mean FVC increased significantly (p less than 0.001). There was a low incidence of side effects and, in contrast to previous reports on TAO, no patient had even a transient increase in cushingoid appearance. Glucose intolerance was observed initially in three patients but resolved with continued steroid taper. Transient liver-enzyme elevation was noted in four patients and in each case reversed with a reduction in TAO dosage. The revised protocol is associated with an improved risk-benefit ratio. New guidelines are presented for the use of TAO in severe steroid-requiring subjects with asthma.
Adult↗
A Canadian multicenter study with Zaditen (ketotifen) in the treatment of bronchial asthma in children aged 5 to 17 years.
One hundred thirty-eight children with chronic asthma, requiring daily treatment with bronchodilators, took part in a 7-month, double-blind, multicenter clinical study. Patients were randomized into two groups, and after a 1-month baseline, were administered Zaditen (ketotifen), 1.0 mg twice daily, or an identical placebo for a period of 6 months. After 10 weeks of receiving the study medication, bronchodilator use was reduced or stopped. In the Zaditen-treated group, 60% of the children taking theophylline were able to stop its use completely, compared to 34% of the patients taking placebo (p less than 0.05). Of the patients who were unable to stop taking theophylline, the Zaditen-and placebo-treated groups recorded average dosage reductions of 62% and 26%, respectively. These differences were statistically significant (p less than 0.05). Thus, a high percentage of patients in the placebo-treated group maintained asthma symptom control with theophylline, whereas most of the Zaditen-treated patients could stop using this medication. Although pulmonary function readings improved in both groups, those patients taking Zaditen demonstrated earlier improvement and greater changes from baseline. Significant differences (p less than 0.05) in favor of Zaditen were found for reduction of concomitant medications, patient's global evaluation, physician's clinical evaluations, incidence of emergency room visits for asthma, and upper respiratory tract infections. No unexpected side effects were observed. It is concluded that Zaditen is an effective medication for long-term control of asthma in children.
Adolescent↗
Bronchodilator therapy in cystic fibrosis: for better or worse?
As one approach to the management of the respiratory manifestations of cystic fibrosis, bronchodilators have been used to try to alleviate symptomatology. Several bronchodilators have been tested with varying degrees of success depending on the parameters measured, the method of patient selection for trials and the time of the study. In some instances the use of bronchodilators has proven detrimental to lung function. In general, it appears that bronchodilator therapy may be beneficial or hazardous and must be evaluated on an individual patient basis. Repeated assessments of respiratory function are necessary and the patient's management must be frequently re-evaluated.
Age Factors↗
Small airways response to naturalistic cat allergen exposure in subjects with asthma.
BACKGROUND: It is currently unclear whether the small airways (diameter <2 microm) contribute significantly to late asthmatic reactions to inhaled allergen. OBJECTIVES: We sought to determine whether naturalistic exposure to cat allergen induced late responses in the small airways as measured by pulmonary function testing and high-resolution computed tomography (HRCT) of the chest performed at end-expiration. METHODS: In a group of 10 subjects with cat-induced asthma, physiologic studies (spirometry and lung volumes, including closing volume) and HRCT were performed before and 6 and 23 hours after a cat room challenge that caused a 20% or greater acute fall in FEV(1). RESULTS: There was no significant decline in FEV(1) at 6 or 23 hours after cat exposure. Forced expiratory flow at 25% to 75% of forced vital capacity was significantly decreased at 6 hours after the challenge and returned to normal by 23 hours. HRCT image analysis as well as closing volume demonstrated increased air trapping from baseline at both 6 and 23 hours after the challenge. In addition, image analysis demonstrated a significant increase in small airways hyperresponsiveness to methacholine at 23 hours after the challenge. No significant mean changes were noted in lung volumes at either 6 or 23 hours or in PC(20) FEV(1) at 23 hours postchallenge. CONCLUSION: These findings demonstrate that naturalistic exposure to cat allergen results in significant small airways obstruction and hyperresponsiveness persisting for at least 23 hours, at which time these changes cannot be detected by conventional physiologic measures. CLINICAL IMPLICATIONS: Physiologically silent distal lung inflammation persists after an antigenic challenge.
Adult↗
Adiposity, asthma, and airway inflammation.
BACKGROUND: Several studies have found obesity to be associated with an increased prevalence of asthma. For reasons that remain unclear, this association has often been reported to be stronger in women than in men. One possible explanation might be that these studies have used body mass index to identify adiposity, which might be a less reliable measure of body fat in men than in women. OBJECTIVE: We sought to explore the association between body fat percentage measured by means of bioelectrical impedance analysis and asthma, airflow obstruction, and airway inflammation in men and women. METHODS: Respiratory questionnaires, spirometry, bronchodilator response, exhaled nitric oxide level, and percentage of body fat were measured in a population-based cohort of approximately 1000 individuals at age 32 years. RESULTS: There was a significant association between the percentage of body fat and asthma in women (P = .043) but not in men (P = .75). Airflow obstruction was associated with percentage of body fat in women (P = .046), but there was an inverse association in men (P = .010). Bronchodilator responsiveness was also associated with lower body fat in men (P = .004). Airway inflammation, measured by means of exhaled nitric oxide, was not associated with body fat in either women (P = .17) or men (P = .25). CONCLUSION: Adiposity is associated with asthma and airflow obstruction in women. This does not appear to be mediated by airway inflammation. In men airflow obstruction and bronchodilator responsiveness are associated with a lower percentage of body fat. CLINICAL IMPLICATIONS: In women, but not in men, obesity is associated with asthma and airflow obstruction, but there was no association with airway inflammation.
Adipose Tissue↗
Air trapping in mild and moderate asthma: effect of inhaled corticosteroids.
BACKGROUND: Air trapping reflects small airway obstruction in asthma and can be assessed quantitatively by high-resolution computed tomography (HRCT). Hydrofluoroalkane-beclomethasone dipropionate (HFA-BDP) is deposited across all sizes of airways, including the small ones. However, its long-term effect on air trapping remains unknown in uncontrolled asthma. OBJECTIVES: To compare the effect of inhaled corticosteroids of different particle size - HFA-BDP and fluticasone propionate (FP) - on lung attenuation in mild-to-moderate uncontrolled asthma. METHODS: A randomized study was performed to analyze the effect of HFA-BDP (400 microg/d) or FP (500 microg/d) given over a period of 3 months to patients with uncontrolled mild-to-moderate asthma. HRCT was performed with spirometric gating, and lung attenuation was measured at residual volume and at pulmonary total capacity. The difference between inspiratory and expiratory attenuation was calculated as an air trapping index. RESULTS: Twenty-five out of 58 patients had abnormal air trapping and could be included in the study. Lung attenuation significantly diminished in the posterior zones of the lung after a 3-month treatment with HFA-BDP or FP, but the difference between the groups was not significant. Adjusted mean variations of the air trapping index from baseline to treatment completion were 34.3 (11.2, 57.3) and 27.3 (6.4, 48.2) for the HFA-BDP and FP groups, respectively. However, the reduction of air trapping area was more pronounced in the group treated with HFA-BDP. CONCLUSION: Inhaled corticosteroids decrease air trapping in uncontrolled asthma regardless of their particle size. CLINICAL IMPLICATIONS: In mild-to-moderate asthma, air trapping assessed by HRCT may be a new outcome related to the control of the disease.
Administration, Inhalation↗
Bronchial hyperreactivity and spirometric impairment in patients with seasonal allergic rhinitis.
UNLABELLED: We previously demonstrated in a group of patients with perennial allergic rhinitis alone, impairment of spirometric parameters and high percentage of bronchial hyperreactivity (BHR). Thus, the present study aimed at evaluating a group of subjects suffering from seasonal allergic rhinitis alone to investigate the presence of spirometric impairment and BHR both during and outside the pollen season. METHODS: One-hundred rhinitics sensitized to pollen allergens only were evaluated during and outside the pollen season. Spirometry and methacholine bronchial challenge were performed. RESULTS: Four rhinitics showed impaired values of FEV1 without referred symptoms of asthma during the pollen season. FEF 25-75 values were impaired in 17 rhinitics during the pollen season and in 11 rhinitics outside the pollen season (P<0.05). Fifty-four patients showed positive methacholine bronchial challenge both during and outside the pollen season. PD20/FEV1 methacholine was lower during the pollen season than outside (P<0.05). In BHR positive patients, reduced values of FVC (P<0.05), FEV1 (P<0.05), and FEF 25-75 (P<0.01) were significantly demonstrated in comparison with BHR negative rhinitics. There was a relationship between BHR degree and FEF 25-75 values only during the pollen season (P<0.001). CONCLUSIONS: This study evidences that an impairment of spirometric parameters may be observed also in patients with seasonal allergic rhinitis alone during the pollen season. A high percentage of these patients had BHR. A close relationship between upper and lower airways is confirmed also in the model of pollen allergy. Thus, a careful evaluation of lower airways should be performed also in those patients with seasonal allergic rhinitis alone.
Adult↗