Effects of bisoprolol on cardiac function and exercise in patients with heart failure

OBJECTIVE

To assess the effects of bisoprolol on exercise capacity and ventricular function in patients with heart failure.

METHODS

Clinical and hemodynamic variables, ventricular function and remodeling, and ergospirometry of patients with heart failure of different etiologies were evaluated before and after the administration of bisoprolol.

RESULTS

Twenty-two patients were analyzed; one patient did not tolerate medication and 14 patients reached the study goal. The group consisted of 9 men and 5 women, the mean age was 52 (36-64) years, and patients were followed during 551 days (238-1109). We observed an improvement in NYHA functional class, reduction in resting heart rate (78.8+/-8.7 vs 63+/-6.4 bpm, p <0.001), increase in left ventricular ejection fraction (31.3+/-8.5% vs 39+/-14.7%. p=0.043), and a tendency towards improved quality of life scores (31+/-20.6 vs 17.8+/-14.8. p=0.058). The maximum heart rate dropped during exercise (138.1+/-20.2 vs 116.7+/-27.1. p=0.01), as did peak oxygen consumption (20.9+/-6.8 vs 15.1+/-3.5. p<0.001); no change was observed on the EV/VCO2 slope. The effects were observed for all etiologies, including Chagas disease.

CONCLUSION

Bisoprolol was safe and well tolerated in patients with heart failure. Bisoprolol therapy improved the symptoms, hemodynamic variables, as well as the cardiac function for all etiologies; however, it did not result in improved exercise capacity.

Experience using centralized spirometry in the phase 2 randomized, placebo-controlled, double-blind trial of denufosol in patients with mild to moderate cystic fibrosis

BACKGROUND

Centralized spirometry may significantly improve quality of spirometry and reduce variability of this outcome measure in clinical trials in cystic fibrosis (CF).

METHODS

Spirometry was performed during the phase 2 randomized, placebo-controlled, double-blind clinical trial of denufosol in patients with mild to moderate CF using American Thoracic Society guidelines. Uniform spirometers were used with electronic data transmission of all the data to a reading center. Spirometry was evaluated for quality by a central reader based on start of test, cough during the test, and evidence of a plateau.

RESULTS

A total of 1418 spirometry values were assessed in 89 subjects during the trial. In only 5 instances did the central reading center need to give feedback to sites regarding the quality of spirometry. The study site data matched the central reading center's data for all but 78 (6%) spirometry values in 33 patients. Many of these differences were small with only 35 (3%) values differing by more than 50 mL in 26 patients.

CONCLUSION

Spirometry in this clinical trial was of high quality with low rate of significant centralized over-read.

[Nitrofurantoin-induced lung disease: about two cases]

INTRODUCTION

Nitrofurantoin is commonly used in the treatment of urinary tract infection and may cause a potential severe complication: interstitial lung diseases.

CASE REPORT

A 78-year-old and an 87-year-old woman treated with nitrofurantoin since respectively 10 months and 6 years developed cough and dyspnea. Antibiotics were ineffective and interstitial lung disease was found. Nitrofurantoin's stopping allowed a clinical and radiological improvement.

CONCLUSION

A good medical supervision is important when nitrofurantoin is prescribed for a long time. The treatment has to be stopped when respiratory symptoms appear to allow an improvement of the symptoms.

Does dipyrone have any effect on respiratory function in COPD patients?

OBJECTIVE

Dipyrone (Novalgin) is an effective analgesic, antipyretic agent also with spasmolytic effects on various types of smooth muscles. It has recently been reported that dipyrone relaxes tracheal smooth muscle of guinea pig. In this present study, we aimed to investigate whether this and previously reported in vitro results have any consequences on the respiratory function of normal healthy volunteers and chronic obstructive pulmonary disease (COPD) patients.

METHODS

In this one-centered, non-randomized, non-comparative, open labelled study, 15 normal healthy volunteers and 15 stable COPD patients, with partially reversible bronchospasm, diagnosed according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria were enrolled in the study at the time they had any indication of dipyrone use. The spirometric tests were performed by a portable notebook and Medikro Spiro2000 spirometry programme-software 1.6 version, before 30, 60, 90, and 120 min after 20 mg/kg of orally dipyrone intake. Groups were compared with the General Linear Model Repeated Measures analysis of variance.

RESULTS

None of the spirometric parameters evaluated showed any significant differences when compared with the baseline values in both groups.

CONCLUSION

While dipyrone had no bronchodilator effects on either COPD patients or normal volunteers, it also did not impair the spirometric parameters. Since COPD is a disease characterized by a progressive and largely irreversible airflow limitation, dipyrone has no observable bronchodilator effect. However, since dipyrone does not impair the pulmonary function, it can be used safely in COPD patients when there is an indication.

Low-level exposure to organophosphate pesticides leads to restrictive lung dysfunction

Apart from symptomology, there are very few reports on lung function following exposure to low levels of organophosphate (OP) pesticides in man. Twenty-five occupationally exposed farmers and 22 environmentally exposed freshwater fishermen were evaluated between and during OP spray seasons. Forty marine fishermen living away from agricultural areas were recruited as a control group. Forced vital capacity (FVC) and forced expiratory volume in the first second (FEV(1)) were measured by spirometry. Haemoglobin corrected erythrocyte acetylcholinesterase (AChE) levels were measured during and between (baseline estimation) spray seasons using a portable WHO-approved Test-mate system (EQM Research, Ohio). FVC ratio was lower in the farmers as compared to the controls (P<0.001) between exposure seasons. In the farmers, FVC ratio decreased further during the exposure season (P=0.023). FEV(1) was lower in the farmers as compared to the controls in both periods (P<0.05). In the fishermen, the decrease in ratios of FVC and FEV(1) following exposure to pesticides was not significant. FEV(1)/FVC ratios were similar in the three groups between (P=0.988) and during (P=0.159) exposure periods. Following exposure to OPs, AChE levels dropped 12.75% in the farmers (P<0.001) and 5.62% in the freshwater fishermen (P=0.001). Occupational exposure to OP results in restrictive lung dysfunction, a phenomenon not observed following environmental exposure.

Formoterol induces tolerance to the bronchodilating effect of Salbutamol following methacholine-provocation test in asthmatic children

OBJECTIVES

To study whether Formoterol treatment affect the bronchodilator response to salbutamol after methacholine-provocation test (MPT) in asthmatic children.

STUDY DESIGN

A prospective, double-blind, randomized, placebo-controlled study. Children aged 7-16 years with mild-persistent to moderate asthma treated with inhaled corticosteroids, were enrolled. After 2-weeks of run-in period, subjects were randomized to inhaled Formoterol 9 microg bid (n=19) or placebo (n=19) for 2 weeks. MPT with salbutamol-recovery curve was performed at the beginning and at the end of the trial period. Measurements of peak expiratory flow rate (PEFR), symptoms score, rescue bronchodilator usage and side effects were recorded daily. The primary end-points were the change in FEV1 0-10 min after salbutamol inhalation and the recovery time from 80 to 100% of pretest FEV1. Statistical analyses were performed by ANOVA with repeated measures.

RESULTS

There was a decrease in the bronchodilator response to salbutamol and an improved PEFR in the Formoterol group. There was no difference in all other parameters.

CONCLUSION

Formoterol decreases the bronchodilator response to salbutamol following MPT. Whether this phenomenon has clinical implication during acute asthma needs further studies.

The 24 h duration of bronchodilator action of the budesonide/formoterol combination inhaler

INTRODUCTION

The duration of bronchodilator action of the long-acting beta-agonist formoterol when administered in the evening has not been investigated. In this study we have investigated whether a single evening dose of formoterol, administered from the combination budesonide/formoterol (BUD/F) Turbuhaler significantly attenuates the circadian rhythm in airway tone over 24 h.

METHODS

Twenty subjects with mild to moderate asthma (mean FEV1 84% predicted) participated in a double-blind, placebo-controlled, cross-over study. Subjects inhaled, in random order, placebo or BUD/F (2x100/6 microg) administered in the evening (2000 h) on two separate occasions. Lung function measurements including FEV1, specific airways conductance (sGaw) and maximum expiratory flow at 25-75% of vital capacity (MEF(25-75%)) were assessed at baseline, at 1 h and subsequently every 4 h post-dose for 24 h.

RESULTS

Compared with placebo, BUD/F significantly improved the three measures of airways function throughout the 24 h period, with a difference in FEV1 at 24 h of 0.20L (0.04-0.35L). BUD/F attenuated the biphasic pattern of the circadian rhythm in airway tone.

CONCLUSION

The single evening administration of formoterol from the combination BUD/F inhaler resulted in a duration of bronchodilation of at least 24 h.

Nasal administration of albuterol: an alternative route of delivery

The use of metered-dose inhalers for the delivery of albuterol, a beta2-selective adrenergic agonist, is associated with drawbacks, especially in children and the elderly. This investigation was designed to assess the effectiveness of albuterol delivered intranasally and to compare this delivery route with intratracheal and intravenous delivery. Three parameters of pulmonary function (peak maximal expiratory flow, maximal expiratory flow at 50% vital capacity, and total lung capacity) in anaesthetized, artificially ventilated guinea pigs were used to determine the degree of protection produced by albuterol against bronchoconstrictor responses provoked by acetylcholine. The heart rate was also measured. Although intranasal albuterol induced a slower protective action during the very initial phase of absorption, the drug was shown to be equally effective when administered either intranasally or intratracheally. In contrast, despite a significant effect initially in the case of intravenous albuterol, its ability to influence pulmonary function faded rather rapidly. No statistically significant differences in heart rate could be detected among the different treatment groups. In conclusion, intranasal albuterol may offer an alternative to metered-dose inhalers for the treatment of acute bronchospasm and for prevention of exercise-induced asthma, especially for children and the elderly.

The pharmacodynamic effects of single inhaled doses of formoterol, tiotropium and their combination in patients with COPD

The aim of this double-blind, double-dummy, cross-over, randomized, pilot study was to compare the acute bronchodilator efficacy of a single dose of formoterol with that of tiotropium in patients with stable chronic obstructive pulmonary disease (COPD). Because the potential of tiotropium for additive effects is yet unknown, the acute effects of adding this anticholinergic agent to formoterol were also explored. A total of 20 outpatients with stable COPD were enrolled. Single doses of 12 microg formoterol, 18 microg tiotropium, and 12 microg formoterol+18 microg tiotropium were given. Serial measurements of FEV1 were performed over 24 h. Formoterol, either alone or in combination with tiotropium, elicited a significantly faster onset of action and showed a trend for a greater maximum bronchodilation than tiotropium alone. At 24 h, mean FEV1 continued to be significantly higher than pre-dosing value following tiotropium and formoterol+tiotropium. These findings indicate that formoterol and tiotropium have different profiles that make both agents attractive alternatives in the treatment of stable COPD. Since tiotropium ensures prolonged bronchodilation, whereas formoterol adds fast onset and a greater peak effect, the two drugs appear complementary.

Salmeterol & fluticasone 50 microg/250 microg bid in combination provides a better long-term control than salmeterol 50 microg bid alone and placebo in COPD patients already treated with theophylline

Bronchodilator agents are central to the symptomatic management of Chronic Obstructive Pulmonary Disease (COPD), and long-acting inhaled bronchodilators are regarded as more convenient. The role of inhaled corticosteroids still remains controversial, but there is increasing evidence that they may improve FEV(1) and symptoms in the long-term.

AIM

of the present small pilot study was to compare Salmeterol & Fluticasone (SM&FP) 50/250 microg bid via a single Diskus inhaler with SM 50 microg bid alone, and with placebo (P) in the treatment of moderate COPD.

METHODS

Eighteen moderate COPD patients (53-77 yr, mean basal FEV(1)=49.1% pred.+/-5.0 s.d.; mean FEV(1) reversibility=3.6% bsln+/-3.8 s.d.) treated with theophylline 400 mg/day and beta(2) short acting prn, were divided into three matched groups of six subjects according to a double-blind design, and treated with SM&FP 50/250 microcg, or SM 50 microcg alone, or P via Diskus inhaler bid for 52 weeks. In bsln, after 4, 12, 24, 36 and 52 weeks, FEV(1) (% pred), morning PEF (l/s), the daily symptom score, and the number of exacerbations (compared with the previous year) were considered. Statistics. t-test, anova in each treatment group, and anova among basal values and among the 52 week values were used, being p<0.05 accepted. Also changes (DeltaFEV(1)) from baseline were compared at different control times.

RESULTS

The mean number of exacerbations/yr decreased from 3.5+/-0.8 to 1.16+/-0.75 s.d. exacerbation/yr in the SM&FP group (t-test p<0.001); from 3.0+/-0.89 to 2.3+/-0.81 s.d. in the SM group (t-test p=ns); and from 3.16+/-1.16 to 4.16+/-0.75 s.d. in the P group (t-test p=ns). Patients receiving SM&FP showed the highest mean improvement in FEV(1) (+7.3%+/-3.3 s.d.) over the baseline pre-treatment value after 36 weeks of treatment (anova p<0.001), being FEV(1) unchanged after 52 weeks of treatment in SM group (+0.33%+/-2.4 s.d.) and with a substantial decrease following P (-2.6%+/-1.2 s.d.) (anova p<0.001). Morning PEF (l/min) increased in subjects treated with SM&FP (anova p<0.001), while it remained unchanged in SM and P group (in both, anova p=ns). After 52 weeks of treatment, only subjects treated with SM&FP showed a reduction of the daily symptoms score from 3.6+/-0.7 to 2.0+/-0.2 s.d. (anova p=0.008). Daily beta(2) short acting prn consumption was reduced only in SM&FP group from 4.2+/-0.81 to 2.2+/-1.2 s.d. after 52 weeks (anova p<0.001).

CONCLUSIONS

SM&FP 50/250 microcg regularly assumed in combination via a single Diskus inhaler for a 52 week period improves respiratory function (such as FEV(1), morning PEF), and and symptom score significantly in moderate COPD previously treated with theophylline, and at an higher extent than SM alone or P. The use of beta(2) short acting prn is also reduced, together with the number of exacerbations.

Maximal forced expiratory maneuver to measure airway obstruction in allergen challenged mice

Our purpose was to develop a method of using a maximal forced expiratory maneuver (MFEM) for the study of bronchoconstriction and bronchial hyperreactivity (BHR) induced in mice by ovalbumin (OA) inhalation challenge. Eight mice (group I) were sensitized and then provocated with OA. Pulmonary function testing (PFT) at baseline and after varying doses of acetylcholine challenge was performed. Eight weight-matched normal mice served as controls (group II). Pulmonary functions include MFEM, dynamic respiratory system compliance (Crs) and respiratory system resistance (Rrs). The results showed that mice treated with OA had worse PFTs than normal controls, characterized by lower MFEF 50%, FEV0.1 and Crs but higher Rrs. The OA-sensitized mice also had more severe bronchoconstriction in response to acetylcholine, characterized by greater decreases in MFEF 50%, FEV0.1 and Crs but a higher Rrs than the controls. There was a good correlation between PD20MFEF50%Ach and PD20FEV0.1Ach with PD20CrsAch and PD20RrsAch. In conclusion, the MFEM can be used to evaluate airway obstruction and BHR induced in mice by allergen challenge.

Effect of salbutamol on lung function parameters of healthy children

In the present study, the effect of 200 microg salbutamol compared to placebo was evaluated on lung function parameters of 37 healthy children aged 7-14 years. Salbutamol or placebo were administered, using a single blind study design, and spirometry was performed before and after 10 min of inhalation. At the time of the study, all children were symptom-free and had not suffered from any respiratory infection during the previous 4 weeks. The administration of salbutamol resulted in a significant increase of mean forced expiratory volume in 1 s (111%-115%, P<0.05), maximal expiratory flow at 50% of forced vital capacity (101%-110%, P<0.05) and maximal expiratory flow at 25 % of forced vital capacity (96%-115%, P<0.05). The administration of placebo resulted in no significant change in lung function parameters.

CONCLUSION

The administration of 200 microg salbutamol results in the occurrence of a small but significant bronchodilation in healthy, non-asthmatic children.

The role of antileukotrienes in the treatment of asthma

OBJECTIVE

This article reviews the literature on the role of antileukotrienes (anti-LTs), specifically montelukast, zafirlukast, and zileuton, in the treatment of asthma.

DATA SOURCES

Relevant and appropriate controlled clinical studies were used. Only literature in the English language was reviewed.

STUDY SELECTION

Material was taken from academic/scholarly journals, appropriate reviews, and published abstracts.

RESULTS

In guidelines established by the National Asthma Education and Prevention Program and the National Heart, Lung, and Blood Institute, a stepwise approach to asthma management is recommended, with recommendations varying depending on degree of disease severity. The anti-LTs, the newest class of drugs for the treatment of asthma, play a circumscribed role in the guidelines as they were only recently available when the latest guidelines were published. Subsequently, however, extensive clinical experience with the anti-LTs has been amassed. Multiple clinical studies have demonstrated that the anti-LTs improve pulmonary function and quality of life, and reduce asthma symptoms, asthma exacerbations, and use of beta2-agonists and oral steroids. The anti-LTs may be particularly useful in asthma patients with aspirin sensitivity or concomitant allergic rhinitis, as well as in pediatric patients. These agents have additive effects with inhaled corticosteroids and may permit a reduction in inhaled corticosteroid dosages.

CONCLUSIONS

The anti-LTs have several features that are likey to promote adherence to treatment and are generally well tolerated. The available clinical data suggest that anti-LTs should be considered as a therapeutic option or as additive therapy in patients with mild to severe asthma.

Enhanced prostaglandin E2 secretion in sputum from asthmatic patients after zafirlukast therapy

BACKGROUND AND PURPOSE

Leukotrienes are important inflammatory mediators of bronchial asthma that cause bronchoconstriction, mucous secretion, and increased vascular permeability. Current guidelines recommend anti-leukotriene agents as alternative treatments for asthma; however, data on their anti-inflammatory effect is lacking.

METHODS

The purpose of this study was to determine the anti-inflammatory effect of zafirlukast, a leukotriene antagonist, in patients with bronchial asthma. A total of 30 adult patients with mild persistent asthma received 6 weeks of zafirlukast treatment. Peak expiratory flow rate (PEFR) was determined before and after therapy to assess clinical efficacy. Both serum and sputum samples were collected before and after therapy and concentrations of eosinophil cationic protein (ECP), prostaglandin E2 (PGE2), and leukotriene E4 (LTE4) were measured.

RESULTS

A significant improvement in PEFR was found after zafirlukast therapy (p = 0.017). There was also a significant reduction in serum ECP concentration (13.6 +/- 2.4 micrograms/L vs 10.3 +/- 2.1 micrograms/L, p < 0.025) and a significant increase in sputum PGE2 concentration (112.7 +/- 14.0 pg/mL vs 176.8 +/- 32.1 pg/mL, p < 0.01). The percentage eosinophil count and the concentrations of ECP and LTE4 in the sputum were not significantly different after therapy.

CONCLUSION

This study found a significant reduction in serum ECP and a significant increase in sputum PGE2 concentrations in asthmatic patients after zafirlukast treatment, both of which were significantly associated with improvement in PEFR. The modulation of PGE2 and ECP production might occur through the anti-inflammatory effect of zafirlukast.

Lidocaine inhalation for local anaesthesia and attenuation of bronchial hyper-reactivity with least airway irritation. Effect of three different dose regimens

The inhalation of lidocaine attenuates bronchial hyper-reactivity but also causes airway irritation. However, how lidocaine dose and plasma concentration influence relationships are unknown. Accordingly, we evaluated the effects of three concentrations of lidocaine (1, 4, and 10%, total dose of 0.5, 2.0, and 5.0 mg kg-1, respectively) vs. placebo in 15 mild asthmatic patients, selected by their response to a histamine challenge (decrease in FEV1 > 20% to less than 18 mg mL-1 of histamine [PC20]). Baseline lung function, histamine-induced bronchoconstriction, topical anaesthesia, and lidocaine plasma concentrations were obtained. FEV1 following lidocaine inhalation showed the greatest decrease for the highest dose (from 3.79 +/- 0.15-3.60 +/- 0.15; P = 0.0012). Lidocaine inhalation increased baseline PC20 (6.1 +/- 1.3 mg mL-1) significantly (to 11.8 +/- 3.1, 16.1 +/- 3.3, and 18.3 +/- 4.5 mg mL-1, respectively) with no difference between the two highest doses. The duration of local anaesthesia was not significantly different between lidocaine concentrations of 4% and 10%. Thus, lidocaine inhalation, with increasing concentrations of the aerosolized solution, increases initial bronchoconstriction while significant attenuation of bronchial hyper-reactivity is not further enhanced with increasing concentrations from 4 to 10%. Plasma concentrations of lidocaine were always far below the toxic threshold. In conclusion, when local anaesthesia of the airways is required a lidocaine dose of 2.0 mg kg-1 as a 4% solution can be recommended for local anaesthesia and attenuation of bronchial hyper-reactivity with the least airway irritation.

Respiratory mechanics and maximal expiratory flow in the anesthetized mouse

Mice have been widely used in immunologic and other research to study the influence of different diseases on the lungs. However, the respiratory mechanical properties of the mouse are not clear. This study extended the methodology of measuring respiratory mechanics of anesthetized rats and guinea pigs and applied it to the mouse. First, we performed static pressure-volume and maximal expiratory flow-volume curves in 10 anesthetized paralyzed C57BL/6 mice. Second, in 10 mice, we measured dynamic respiratory compliance, forced expiratory volume in 0.1 s, and maximal expiratory flow before and after methacholine challenge. Averaged total lung capacity and functional residual capacity were 1.05 +/- 0.04 and 0.25 +/- 0.01 ml, respectively, in 20 mice weighing 22.2 +/- 0.4 g. The chest wall was very compliant. In terms of vital capacity (VC) per second, maximal expiratory flow values were 13.5, 8.0, and 2.8 VC/s at 75, 50, and 25% VC, respectively. Maximal flow-static pressure curves were relatively linear up to pressure equal to 9 cm H(2)O. In addition, methacholine challenge caused significant decreases in respiratory compliance, forced expiratory volume in 0.1 s, and maximal expiratory flow, indicating marked airway constriction. We conclude that respiratory mechanical parameters of mice (after normalization with body weight) are similar to those of guinea pigs and rats and that forced expiratory maneuver is a useful technique to detect airway constriction in this species.

Mediators in hyperpnea-induced bronchoconstriction of guinea pigs

Both tachykinins and leukotrienes (LTs) have been demonstrated to be the mediators for hyperpnea-induced bronchoconstriction (HIB) of guinea pigs. We tested the hypothesis that leukotrienes modulate HIB indirectly by triggering tachykinin release. Ninety nine young guinea pigs were divided into four groups: control; LTC4; FPL 55712 (a LT receptor antagonist); and MK-886 (an inhibitor of LT synthesis). Each animal was anesthetized, cannulated, paralyzed, and artificially ventilated. The protocol included the baseline, hyperpnea, and recovery periods. Thus, animals in each group were further divided into three subgroups: baseline; recovery-3 min; and recovery-8 min. We measured dynamic respiratory compliance (Crs), forced expiratory volume in 0.1 s (FEV0.1) and maximal expiratory flow at 30% total lung capacity (Vmax30), as well as determined substance P (SP) and LT levels in plasma and bronchoalveolar lavage (BAL) during either the baseline or the recovery (3 or 8 min) period. Hyperpnea caused decreases in Crs, FEV0.1 and Vmax30, indicating HIB, in the control group at 3 min and 8 min of the recovery period. Both FPL 55712 and MK-886 significantly attenuated HIB. In the control group, hyperpnea caused significant increases in SP and LT levels in both plasma and BAL. These increases in SP levels were significantly suppressed, however, by FPL 55712 and MK-886. Compared to the control group, infusion of LTC4 did not significantly alter either HIB, SP or LT levels in most cases. An additional group of 24 animals treated with neurokinin-2 receptor antagonist, SR 48968, demonstrated that SR 48968 significantly suppressed hyperpnea-induced increases in plasma, but not in BAL, LT levels. Since FPL 55712 and MK-886 first suppress LT activities, these results suggest that suppressed LT activities attenuate HIB indirectly via reducing tachykinin release.

Lung function growth and ambient ozone: a three-year population study in school children

We followed a cohort of 1,150 children for 3 yr to investigate long-term effects of ambient ozone. Nine study sites were selected on the basis of air-quality data to represent a broad range of ozone exposure. In 1994, 1995, and 1996 lung function was recorded biannually, always before and after summertime. The effect of ozone was analyzed with regression analyses and study-site, a child's sex, atopy, passive smoking, baseline lung function, and increase in height were considered as confounding variables. A negative effect of summertime ozone on the pre- to post-summer-time change in FEV(1) (ml/d) was present in 1994 (beta = -0.019 ml/d/ppb; p < 0.01) and in 1995 (beta = -0.017 ml/d/ ppb; p < 0.05), but not in 1996 (beta = 0. 004 ml/d/ppb; p = 0.6); corresponding estimates for FVC were in 1994: beta = -0.022 ml/d/ppb, p < 0.005; 1995: beta = -0.018 ml/d/ppb, p < 0.05; and 1996: beta = 0.006 ml/d/ppb, p = 0.46. When all three study years were considered simultaneously, i.e., the changes in lung function between each of two subsequent surveys being the dependent variable, summertime ozone was associated with a lesser increase in FEV(1) (beta = -0.029 ml/d/ppb; p < 0.001), FVC (beta = -0.018 ml/d/ppb; p < 0.001), and MEF(50) (beta = -0.076 ml/s/d; p = 0.001). No consistent associations were observed for lung function and NO(2), SO(2) and PM(10). Long-term ambient ozone exposure might negatively influence lung function growth.

Lung function in school-aged asthmatic children with inhaled cromoglycate, nedocromil and corticosteroid therapy

Two-thirds of the children with asthma in our area use cromones and only one-third steroids as the maintenance therapy. This study aimed to evaluate our treatment policy based on the international consensus. Peak expiratory flow (PEF), dynamic spirometry and bronchodilation test results were therefore collected in 195 school-aged patients who visited our outpatient clinic in 1995. Sixty-four children (33%) used cromoglycate, 86 (44%) nedocromil and 45 (23%) inhaled steroids. Twenty-five (12%) needed combination therapy, mainly with salmeterol. Lung function results were good, and there were no significant differences between the therapeutic groups irrespective of whether pre- or postbronchodilator values were considered. PEF was decreased in eight (4%), forced expiratory volume in one second (FEVI) in four (2%) and maximum mid-expiratory flow (MMEF) in 33 (17%) patients. At least one result was decreased in 39 (20%) cases, in most cases (77%) MMEF alone. Significant rises after salbutamol inhalations were observed in 17 (9%) in PEF, in two (1%) in FEV1 and 20 (10%) in MMEF values. Thus, the bronchodilation test was positive in 33 (17%) cases, and in 22 (11%) cases it was the only sign of bronchial obstruction. Over 70% of the children with asthma can be treated with cromones by a stepwise treatment modality. Inhaled steroids can be restricted to those not controllable by cromones. Lung function tests, including postbronchodilator values, should be part of the follow-up of continuous maintenance medication for asthma.

Comparison of respiratory inductance plethysmography with thoracoabdominal compression in bronchial challenges in infants and young children

Respiratory inductance plethysmography measuring thoracoabdominal asynchrony (TAA) has been claimed to be a useful tool for measuring changes in airway resistance in infants. In this study we evaluated the response to methacholine by thoracoabdominal compression and respiratory inductance plethysmography. Seventeen infants (mean age, 13.1 +/- 4.7 mo) with recurrent episodes of cough or wheeze underwent bronchial challenge with inhaled methacholine. Lung function was evaluated by measuring maximal expiratory flow at resting lung volume (VmaxFRC), and the degree of TAA was measured by phase angle (theta). Methacholine was inhaled for 1 min during tidal breathing using increasing doubling concentrations until a fall of at least 40% in VmaxFRC was achieved (final concentration). All infants responded to the final concentration of methacholine by a significant fall in VmaxFRC (from 31 +/- 10 to 12 +/- 5 ml/s/kg, p < 0.001). All but one infant responded to methacholine at the final concentration with a significant increase in phase angle (median theta increased from 11.7 to 31.7 degrees, p < 0.001). In two other infants there was an early response in theta compared with the response in VmaxFRC. Phase angle increase after methacholine was expressed as Z-scores (the difference between postmethacholine theta and postbuffer theta divided by the standard deviation of postbuffer theta). An increase of at least 2.0 Z-scores in theta was observed at the same concentration of methacholine when VmaxFRC fell by at least 40% in 15 of the 17 infants (88%). We conclude that respiratory inductance plethysmography is a sensitive method to measure bronchial reactivity to methacholine in most of the infants studied (14 of 17, 82%). A concentration of methacholine causing an increase in theta of at least 2.0 standard deviations above baseline is equivalent to the concentration causing a 40% fall in VmaxFRC.

A cross sectional study of chemical industry workers with occupational exposure to persulphates

OBJECTIVES

Hair bleaches containing persulphates have been identified as the cause of occupational asthma in hairdressers. Also employees in persulphate production with occupational asthma have been described. It was the aim of this study to give an estimate of the prevalence of asthma due to persulphates in chemical workers with exposure to ammonium and sodium persulphate.

METHODS

A cross sectional study was performed in 32 of 33 employees of a persulphate producing chemical plant. Eighteen of 23 workmen from the same plant with no exposure to persulphates were taken as controls. Also, information was collected from medical records of the seven subjects who had left the persulphate production for medical reasons since 1971. Data were recalled by a questionnaire, skin prick tests were performed with five environmental allergens, and ammonium and sodium persulphate (80 mg/ml). Specific immunoglobulin E (IgE) to the same environmental allergens as in the skin test, and total IgE were measured. Lung function and bronchial responsiveness to histamine were assessed by standard procedures. Workplace concentrations of ammonium and sodium persulphate were estimated by area and personal monitoring. The amount of persulphate was analysed as sulphur by inductively coupled plasma emission spectrometry.

RESULTS

Work related rhinitis was reported by one subject with exposure to persulphates, conjunctivitis and bronchitis were reportedly related to work by two controls. There were no cutaneous reactions to persulphates in either group. Four non-atopic subjects exposed to persulphates, and two controls, one atopic and one non-atopic, were considered to be hyperresponsive to histamine. Three subjects exposed to persulphates with bronchial hyperresponsiveness (provocation dose of histamine causing a 15% fall in forced expiratory volume in one second (PD15 FEV1) < or = 1 mg) did not show variability in peak expiratory flow of > or = 20%, the rest refused peak flow measurements. None of the variables showed significant differences between the groups (P > 0.05). Six of the exworkers left because of work related contact dermatitis. Mean values for workplace concentrations of ammonium and sodium persulphate within the bagging plant were below 1 mg/m3, and the maximal concentrations were 1.4 mg/m3 and 3.6 mg/m3, respectively.

CONCLUSION

Exposure to workplace concentrations of ammonium and sodium persulphate of about 1 mg/m3 in this chemical plant was not associated with a risk of occupational asthma.

Overnight protection by inhaled salmeterol on exercise-induced asthma in children

The main aim of the present study was to evaluate whether inhaled salmeterol given in the evening protected against exercise-induced asthma the next morning. Twenty three children (12 males and 11 females) with a mean age of 11 yrs and with exercise-induced asthma participated in a double-blind, randomized, placebo-controlled study. The children inhaled salmeterol 25 micrograms, salmeterol 50 micrograms and placebo by Diskhaler at 10 p.m. on 3 separate days. Next morning, half of the children ran on a motor-driven treadmill for 6 min at submaximal load at 8 a.m. and the remainder at 10 a.m. Lung function was measured by maximal expiratory flow-volume loops before running, immediately after, and 3, 6, 10 and 15 min after running. The mean maximum reduction in forced expiratory volume in one second (FEV1) after treadmill run was 34% before inclusion in the study. Mean maximum fall in FEV1 was significantly greater after placebo: 30% (23-36) 95% confidence interval) than after salmeterol 25 micrograms: 19% (12-23) or salmeterol 50 micrograms: 18% (12-25). In addition to the reduced postexercise bronchoconstriction, pre-exercise lung function (FEV1) was significantly higher both after salmeterol 25 micrograms: 2.4 L.s-1 (2.1-2.7) and salmeterol 50 micrograms: 2.5 L.s-1 (2.2-2.8) than after placebo: 2.2 L.s-1 (1.9-2.5). No significant differences in pre- and postexercise lung function were found between children tested at 8 or 10 a.m., or in relation to salmeterol dosage. Thus, inhaled salmeterol 25 and 50 micrograms offered similar overnight protection against exercise-induced asthma and improved baseline lung function in the morning as compared to placebo.

Effect of nitrogen dioxide and sulphur dioxide on airway response of mild asthmatic patients to allergen inhalation

Air pollution may enhance the airway response of asthmatic subjects to allergen inhalation. To test the hypothesis that sulphur dioxide and nitrogen dioxide alone or in combination could have a contributory role, we have studied the effect of 6 h exposure to air, 200 parts per billion (ppb) sulphur dioxide, 400 ppb nitrogen dioxide, and the two gases together on the airway response to inhaled allergen in ten volunteers with mild atopic asthma. The subjects were exposed to the gases in random order at weekly visits, then challenged with pre-determined concentrations of Dermatophagoides pteronyssinus allergen 10 min after each exposure. The forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and cumulative breath units (CBU) of D pteronyssinus allergen required to produce a 20% fall in FEV1 (PD20FEV1) were measured after each exposure. Compared with air, neither sulphur dioxide nor nitrogen dioxide nor the combination significantly altered FEV1 or FVC. Although the decreases in PD20FEV1 after exposure to each agent alone were not significant (41.2%, p = 0.125 after nitrogen dioxide; 32.2%, p = 0.506 after sulphur dioxide) the decrease after exposure to the combination was significant (60.5 [SE 8.1]%, p = 0.015). Exposure to a combination of sulphur dioxide and nitrogen dioxide in concentrations that could be encountered in heavy traffic enhances the airway response to inhaled allergen, possibly as a result of previous airway inflammation.

Efficacy of cromoglycate in persistently wheezing infants

A prospective study was undertaken to evaluate the efficacy of (sodium) cromoglycate in the treatment of persistent wheezing in 31 children between 4 and 12 months of age. The subjects were randomised to receive either 40 mg of cromoglycate (n = 16) or physiological saline as placebo (n = 15) three times a day by wet nebulisation in a double blind fashion for a period of six weeks. The patients were evaluated with daily symptom scores and respiratory function testing measuring maximal expiratory flow at functional residual capacity (VmaxFRC) before initiating treatment and upon completion. At baseline, mean (SD) symptom scores between the two groups were comparable (cromoglycate 99.5 (29.8), placebo 104.5 (29.7)) as were VmaxFRC expressed as per cent of predicted normals (cromoglycate 48 (28), placebo 46 (20)). Upon completion of the treatment protocol, no significant difference could be found between the two groups for either symptom score (cromoglycate 67.6 (40.2), placebo 58.6 (41.4)), or VmaxFRC (cromoglycate 52 (24), placebo 60 (32)). It is concluded, therefore, that 40 mg of cromoglycate three times a day administered via facemask and wet nebulisation was no more effective than placebo in the treatment of our sample of persistently wheezing infants under 1 year of age.

Inhaled platelet-activating factor increases airway sensitivity but not maximal airway narrowing to methacholine in normal subjects

To examine the effect of inhaled platelet-activating factor (PAF) on airway sensitivity and on maximal airway narrowing, we measured airway response to doubling concentrations of methacholine (MCh) 48 h before and 48 h after inhalation of 10, 50 and 100 micrograms of PAF in six nonatopic, nonasthmatic subjects. The forced expiratory volume in one second (FEV1) and airflow at 30 percent of vital capacity (V30) from partial forced expiration were used to assess changes in airway calibre. Inhalation of PAF caused only minor changes in FEV1. In contrast, inhalation of 100 micrograms of PAF caused a significant fall in V30 from 2.64 +/- 0.35 to 1.35 +/- 0.43 l.min-1 (p < 0.05). Two days after PAF inhalation a leftward shift of the concentration-response curve to MCh was observed. The MCh concentration causing a 20% fall in FEV1 (PC20FEV1) was 11.25 +/- 1.78 and 2.38 +/- 1.29 mg.ml-1 (geometric mean +/- GSEM; p < 0.05) before and after PAF inhalation, respectively. PAF did not affect the maximal airway response to MCh. The maximum percentage fall in FEV1 was 36.2 +/- 1.9% at baseline and 37.6 +/- 1.8% after PAF inhalation. Likewise, maximum percentage change in V30 was 72.8 +/- 3.7% at baseline and 73.6 +/- 3.4% after PAF inhalation. The results of this study show that PAF inhalation increases airway sensitivity without altering the maximal bronchoconstrictive response to MCh in normal subjects.

Effect of inhaled bradykinin on indices of airway responsiveness in asthmatic subjects

Asthma is characterized by airway hyperresponsiveness, a physiopathological abnormality which may result from the complex interplay between inflammatory cells and proinflammatory mediators. Although kinins are thought to play a role in the pathogenesis of bronchial asthma, it is not known whether bradykinin is able to induce airway hyperresponsiveness. We have, therefore, investigated the effect of inhaled bradykinin on the changes in airway calibre and in airway hyperresponsiveness to histamine, in a double-blind, randomized study of nine asthmatic subjects. Subjects were studied on two study periods, separated by at least 15 days. On the first day of each study period, subjects inhaled either a single dose of bradykinin or methacholine (placebo) with changes in airway calibre being followed as forced expiratory volume in one second (FEV1) and as the maximum expiratory flow rate measured at 70% of the vital capacity below total lung capacity (TLC) from a partial forced expiratory manoeuvre (Vp30) at 3, 5, 10, 15, 30, 45 and 60 min, and then every hour for 7 h. Airway responsiveness to histamine, expressed as the provocative concentrations producing a 20% fall in FEV1 and 40% fall in Vp30 (PC20FEV1 and PC40Vp30), was measured at 3 and 7 h after inhaling the agonists, then on days 1, 3, 7 and 14. Inhalation of bradykinin caused rapid bronchoconstriction that peaked at 3-5 min. When compared to placebo, no significant difference in histamine responsiveness was seen after bradykinin in terms of changes in PC20FEV1 values.(ABSTRACT TRUNCATED AT 250 WORDS)

Dose-related protection against histamine-induced bronchoconstriction by inhaled salmeterol

A double-blind crossover study was carried out in 8 subjects to compare the effect of inhaled salmeterol 12.5, 50 and 100 micrograms with inhaled salbutamol 200 micrograms on resting lung function and on bronchoconstriction in response to inhaled histamine up to 12 hours following each treatment. Changes in resting lung function were measured using forced expiratory volume in one second (FEV1) and flow at 70% of vital capacity taken from partial expiratory flow volume curves (pEFR70). The concentrations of histamine which produced a 15% fall in FEV1 (PC15) and a 40% fall in pEFR70 (PC40) were also measured. The peak bronchodilator effect after salmeterol 50 and 100 micrograms was similar in magnitude to salbutamol 200 micrograms. Salmeterol produced dose-related changes in lung function and protection against histamine-induced bronchoconstriction. The duration of the effect of salmeterol (50 and 100 micrograms) was longer than that for salbutamol (200 micrograms). Although pEFR70 is a more sensitive measure of lung function there was no greater separation between different doses of salmeterol than with FEV1. Both salmeterol and salbutamol were well tolerated.

Plasma levels and therapeutic response: the relevance to community pharmacy

An assessment of 26 patients, taking theophylline for COAD or asthma, was undertaken in a Belfast Community pharmacy. Patients had peak flow rate and serum theophylline concentration monitored. Based on these findings patients were counselled and, where appropriate, theophylline dosage was adjusted using a pharmacokinetic computer program. A statistically significant improvement was found between the number of patients who had a serum theophylline concentration in the therapeutic range at the initial assessment and at 3 months and 12 months. This was accompanied by a statistically significant improvement in peak expiratory flow rates.

Effects of salbutamol inhalations on transcutaneous blood gases in children during the acute asthmatic attack: from acute deterioration to recovery

Nine children, 7-16 years of age, were studied repeatedly during an acute asthmatic attack, from acute deterioration to recovery. The transcutaneous blood gases, forced expiratory volume in 1 s (FEV1) and maximum expiratory flow when 25% of vital capacity remained to be expelled (MEF25) were monitored before and after salbutamol inhalation. The flow-volume variables were markedly impaired in the acute phase but improved gradually by the time of recovery. The transcutaneous PO2 (tcPO2) decreased in the acute and early recovery phase but improved by the late recovery phase. In the acute phase, the salbutamol inhalations increased the FEV1, indicating an improvement in central airway function, but also reduced the MEF25 and tcPO2 in some of the children. The changes in tcPO2 after the inhalations correlated with the changes in MEF25 (p < 0.001), thereby indicating a common denominator, probably the condition of the peripheral airways. In the recovery phase, the FEV1, MEF25 and tcPO2 improved after the inhalations (p < 0.05). In conclusion, transcutaneous PO2 can be used to evaluate the effects of treatment in children with acute asthmatic symptoms and may add information about peripheral airway function which may prove particularly valuable in small children where few methods are available for such measurements.

Maprotiline metabolism appears to co-segregate with the genetically-determined CYP2D6 polymorphic hydroxylation of debrisoquine

The plasma concentrations of the tetracyclic antidepressant maprotiline and its effect on histamine-induced bronchoconstriction were measured after single (50 mg) and multiple (50 mg twice daily) oral doses in healthy subjects. Histamine-induced bronchoconstriction was abolished after a single dose of maprotiline and this effect persisted throughout multiple dose treatment. The mean Cmax of maprotiline in six poor metabolisers (PM) of debrisoquine was 2.7-fold greater than that in six extensive metabolisers (EM) and the mean AUC(0,48 h) was 3.5 times higher. The duration of the pulmonary effect of maprotiline after cessation of multiple dose treatment in EM was less than 3 weeks compared with at least 4 weeks in PM.

Effect of salmeterol and formoterol in patients with chronic obstructive pulmonary disease

In the present trial we investigated the time course of inhaled salmeterol and formoterol bronchodilation in comparison with that of inhaled salbutamol and placebo in 16 patients with moderate to severe chronic obstructive pulmonary disease (COPD). The study was performed using a single-blind crossover randomized study. The bronchodilator activity of 200 micrograms salbutamol, 50 micrograms salmeterol, 24 micrograms formoterol and placebo, which were all inhaled from a metered dose inhaler, was investigated. Our results showed that salmeterol and formoterol are efficacious in reducing airflow obstruction in patients suffering from COPD. We found similar times of onset to improve FEV1 by 15% for salmeterol and formoterol (salbutamol behaving faster), while the duration of action showed the expected differences between the two long-acting drugs and salbutamol. The results indicate that long-acting beta 2-agonists appear to be very effective in improving airway limitation in patients suffering from COPD. Although the onset of bronchodilation after inhaling salmeterol and formoterol is slightly delayed compared with salbutamol, this is of little clinical importance since in these patients salmeterol and formoterol must be intended for maintenance treatment and not immediate symptomatic relief.

Carbon dioxide rebreathing method of cardiac output measurement during acute respiratory failure in patients with chronic obstructive pulmonary disease

OBJECTIVE

To compare measurement of cardiac output by the CO2 rebreathing method vs. the thermodilution cardiac output technique in the setting of acute respiratory failure in patients with chronic obstructive pulmonary disease.

DESIGN

Prospective, comparative study of two methods in a consecutive sample.

SETTING

Intensive care unit.

PATIENTS

Twenty-five patients with chronic obstructive pulmonary disease with acute respiratory failure were studied. The patients were being mechanically ventilated and monitored with systemic and pulmonary artery catheters.

MEASUREMENTS AND MAIN RESULTS

Cardiac output was determined, using both the thermodilution technique and an indirect CO2 Fick method. Veno-arterial CO2 content difference was calculated from an estimated mixed venous PCO2 obtained by an equilibrium CO2 rebreathing method and measured PaCO2. PCO2 was converted to content using the equation of the CO2 dissociation curve described by McHardy. A wide range of cardiac output was studied. There was a significant correlation between thermodilution and CO2 rebreathing methods (r2 = .92, p < .001). The mean difference between thermodilution and CO2 rebreathing methods was -0.06 L/min/m2, standard deviation for the bias was 0.028 L/min/m2, and 95% confidence interval for the bias was -0.120 to -0.001 L/min/m2.

CONCLUSION

Our results suggest that the CO2 rebreathing method may be a reliable non-invasive technique to determine cardiac output in mechanically ventilated patients with chronic obstructive pulmonary disease.

Effects of peptidase inhibitors on bradykinin-induced bronchoconstriction in the rat

Objectives of this study were to determine if aerosolized bradykinin causes bronchoconstriction in anesthetized, mechanically ventilated rats, and if pretreatment with enalaprilat, an inhibitor of angiotensin-converting enzyme (ACE), or phosphoramidon, an inhibitor of endopeptidase 24.11 (EP 24.11), alters the response. We found that aerosolized bradykinin elicited a reproducible bronchoconstrictor response that was significantly amplified by pretreatment with aerosolized enalaprilat or phosphoramidon. Neither inhibitor alone affected airway tone or caused nonspecific airway hyperreactivity. These findings indicate that both ACE and EP 24.11 contribute to bradykinin degradation in rat airways.

[Efficacy of disodium cromolyn in adult chronic asthma]

Disodium cromolyn is effective in preventing asthma, but its steroid sparing effect remains controversial. In this prospective cross-over study, we used two different brands of disodium cromolyn, Intal and Ticromil, each for 4 weeks on 7 adult patients with chronic asthma. The dosage was 20 mg qid via a special inhaler. The whole course of the study was 12 weeks for each patient, including 2 run-in weeks and 2 wash-out weeks. Patients were followed up by the same physician at outpatient clinics every 2 weeks to measure FEV1, FVC, peak expiratory flow rate (PEFR), and reversibility after bronchodilator. The physician also assessed the severity of the patients' symptoms via a special score system. Patients recorded symptom severity and frequency of medications at home on daily diary cards. Patients also measured PEFR twice a day. At the end of the treatment, FEV1 was improved more in Intal group; daily prednisolone dosage was markedly reduced in Ticromil group; PEFR was improved in both group; but neither symptom severity nor airway reversibility was significantly changed. When two groups were calculated as a whole, PEFR increased significantly from 294 +/- 20 l/min to 342 +/- 19 l/min (p = 0.0225). The daily prednisolone dosage reduced from 5.87 +/- 0.91 mg to 3.91 +/- 0.60 mg in the 3rd week and to 4.05 +/- 0.63 mg in the 4th week. The differences between these 2 dosages and the baseline dosage were statistically significant (both p < 0.05). Side effects were minimal in all patients. We concluded that after the use of disodium cromolyn for 4 weeks, PEFR was markedly improved and daily prednisolone dosage was also significantly reduced.

Effects of aerosol methacholine and histamine on airways and lung parenchyma in healthy humans

To investigate whether histamine (His) and methacholine (MCh) have different effects on airways and lung parenchyma, 11 healthy subjects were given aerosol MCh until a response plateau was obtained and then two doses of His. At the plateau, forced expiratory volume in 1 s and forced expiratory flow at 40% of vital capacity from partial flow-volume curves were reduced by 19 +/- 3 (SE) and 80 +/- 4%, respectively. Aerosol His decreased forced expiratory volume in 1 s by an additional 12 +/- 1% but left partial forced expiratory flow unchanged. The bronchodilator effect of deep inhalation, as inferred from the ratio of forced expiratory flow from maximal to that from partial flow-volume curves, increased after MCh and plateaued but decreased after His. Quasi-static transpulmonary pressure-volume area determined in seven subjects was unchanged after MCh but was increased by 57 +/- 10% after His. We conclude that adding His after the response to MCh plateaued does not increase the maximal degree of bronchoconstriction but may increase parenchymal hysteresis, thus blunting the bronchodilator effect of deep inhalation. These results suggest that His and MCh have similar effects on airway smooth muscle but different effects on lung tissue properties.

Effect of treatment on maximal expiratory flow rates in tropical eosinophilia

Maximal expiratory flow rates such as peak expiratory flow rate (PEFR), rates at 25%, 50% and 75% of vital capacity (VE max 25%, VE max 50%, VE max 75%) and forced expiratory flow during the middle half of forced vital capacity (FEF 25-75%) were recorded in 23 patients with tropical eosinophilia (TE) before and after treatment. The mean values of all flow rates were significantly lower (P < 0.001) in untreated TE patients compared to predicted values. After three weeks' treatment with diethylcarbamazine, although there was a significant rise in the mean values of all expiratory flow rates (P < 0.05) except VE max 75% (P > 0.2), all flow rates continued to be significantly lower (P < 0.01) at one month than predicted values.

Efficacy and tolerability of nedocromil sodium versus placebo in chronic reversible obstructive airways disease

In this 8-week, double-blind, comparative trial of nedocromil sodium (4 mg q.i.d.) versus placebo in 42 patients with chronic reversible obstructive airways disease, there was a trend in favor of nedocromil sodium compared to placebo in parameters assessed by patients (nocturnal symptom scores, evening PEFR values) and those assessed by clinicians (asthma severity scores) compared with baseline values. There was a statistically significant difference (p < 0.05) in favor of nedocromil sodium in the inhaled bronchodilator requirements in the last 2 weeks of treatment. Both patients' and clinicians' evaluation of the overall efficacy of treatment was significant in favor of nedocromil sodium (p < 0.01 and p < 0.05, respectively). The treatments were well tolerated by the majority of patients. From these data, it can be concluded that nedocromil sodium (4 mg q.i.d.) is of value in the preventive treatment of chronic reversible obstructive airways disease.

Evaluation of the bronchodilating activity and the tolerability of broxaterol administered as a solution by inhalation

The aim of this study was to evaluate the bronchodilating activity and the tolerability of broxaterol (B, CAS 76596-57-1) given as drops by inhalation after single administration at different doses and after repeated administrations for 1 month. Two groups of 12 patients each were treated in a double-blind fashion and according to a within-subject design: one group with B at the single doses of 1.25 mg and 2.50 mg and with placebo (P), and the other with B at the dose of 0.75 mg and with P. A further group of 12 patients was treated in open fashion for 1 month with B at the dose of 1.25 mg 3 times a day. On each study day for the single doses and on the 1st and 30th days for the repeated doses, forced vital capacity (FVC), forced expiratory volume (FEV1), maximal middle expiratory flow (MMEF), heart rate (HR) and systolic and diastolic blood pressure (BP) were measured immediately before and 15, 30, 60, 120 and 240 min after the conclusion of the treatment. At the beginning and at the end of the 1-month treatment period, haematology and biochemistry were checked. After B 0.75 mg, 1.25 mg and 2.50 mg the values of spirometric variables proved significantly and dose-dependently higher than the basal values. The changes from baseline in lung function test values with B (all doses) were significantly greater than with P.(ABSTRACT TRUNCATED AT 250 WORDS)

Axon reflex in resiniferatoxin-induced bronchoconstriction of guinea pigs

To study the role of the axon reflex in resiniferatoxin (RTX)-induced bronchoconstriction in vivo, 32 guinea pigs weighing 292 +/- 7 g were randomly divided into five groups: Group 1, control (n = 6); Group 2, chlorisondamine (n = 6); Group 3, tetrodotoxin (TTX, n = 6); Group 4, local capsaicin application (n = 6); and Group 5, systemic capsaicin application (n = 8). Chlorisondamine was used to interrupt ganglionic transmission while TTX was employed to block nerve impulse conduction. In Group 4, capsaicin was locally applied to both cervical vagus nerves 30 min prior to the study whereas capsaicin was given subcutaneously for 5 days starting 9 days before the study in Group 5. Each animal was anesthesized with pentobarbital sodium, cannulated with a tracheal cannula and venous catheter, paralyzed with gallamine triethiodide, and artificially ventilated. All the above animals were treated with atropine (0.2 mg/kg) and phenoxybenzamine (0.5 mg/kg). Resiniferatoxin (2 micrograms/kg) was injected intravenously to induce airway constriction. Immediately upon injection of RTX (at 1 min), each animal in the control group exhibited decreases in maximal expiratory flow, dynamic respiratory compliance, and total lung capacity, indicating severe bronchoconstriction. Then the airway spasm ameliorated gradually with time. Animals in Groups 3 and 4 indicated partial abolishment, while those in Group 5 showed complete abolishment, of the RTX-induced bronchoconstriction. On the other hand, the animals in Group 2 did not display any significant alteration in the RTX-induced bronchospasm. Furthermore, we tested RTX-induced bronchoconstriction in 5 additional animals not pretreated with either atropine or phenoxybenzamine. Compared with the data above, no significant differences in RTX-induced respiratory changes were found. Since it is known that TTX blocks nerve conduction, the data suggest that the TTX-sensitive reflex (the axon reflex) via afferent C-fibers plays a significant role in the RTX-induced bronchoconstriction, which is apparently mediated via tachykinins.

Pharmacodynamic effects of inhaled dry powder formulations of fenoterol and colforsin in asthma

The airway and tremor response and cardiovascular and hypokalemic effects of single doses of inhalative fenoterol dry powder capsules (0.4 mg) were compared with the fenoterol metered dose inhaler (0.4 mg) and colforsin (forskolin) dry powder capsules (10.0 mg), a direct activator of the adenylate cyclase system, in 16 patients with asthma. Subjects (FEV1 < or = 60% predicted) were investigated in a randomized, double-masked, placebo-controlled, four-period, crossover trial for a 120 minute period. All active drugs caused a significant increase in specific airway conductance (p < 0.05); the order of potency (mean +/- SEM maximum increase from baseline) was fenoterol metered dose inhaler (0.51 +/- 0.06 sec-1 x kPa-1), fenoterol dry powder capsules (0.49 +/- 0.07), and colforsin dry powder capsules (0.30 +/- 0.03). A marked increase in finger tremor amplitude resulted after fenoterol metered dose inhaler only (62.93% +/- 10.21%; p < 0.05) in contrast to fenoterol dry powder capsules (15.84% +/- 4.35%; p < 0.05) and colforsin dry powder capsules (12.87% +/- 10.44%; p > 0.05). A decrease in plasma potassium was found after fenoterol (metered dose inhaler > dry powder capsules; p < 0.05). In conclusion, fenoterol dry powder capsules caused less tremor response and hypokalemic effects than the metered dose inhaler, although the bronchodilator capacity was similar. Colforsin dry powder capsules resulted in a measurable bronchodilatation in patients with asthma.

Upper airway anesthesia induces airflow limitation in awake humans

Upper airway receptors are thought to contribute to upper airway stability by reducing collapsing forces. Their activity can be abolished by topical anesthesia. We have measured in 16 healthy volunteers (mean +/- SD age, 23.7 +/- 1.6 yr) specific airway conductance (SGaw), maximal inspiratory (MIFR) and expiratory (MEFR) flow rates before and 15, 35, and 45 min after extensive upper airway anesthesia (UAA) with 10% lidocaine. Average values of MIFR decreased (p less than 0.01) 15 min after UAA, but they returned to or near to control values at 45 min: MIF25 (4.8 versus 6.0 L/s); MIF50 (5.1 versus 6.2 L/s); MIF75 (4.4 versus 5.3 L/s). Transient decreases in flow (V) rates, reaching zero flow in some subjects, were observed in 13 subjects during forced inspiratory vital capacity (FIVC) maneuvers and in seven subjects during forced expiratory vital capacity (FEVC) maneuvers. MEFR at 25, 50, and 75% FVC, SGaw, and FVC did not change after anesthesia. Simultaneous measurements of supraglottic pressure, V, and lung volume in 12 of the 16 subjects showed that the site of flow limitation was localized at the level of the glottis in all except one subject in whom there was both a glottic and a supraglottic obstruction. We conclude that extensive upper airway anesthesia induced a profound but transitory upper airway obstruction during FIVC and FEVC maneuvers. These findings are compatible with the concept of reflex regulation of upper airway caliber.

Aerosolized lidocaine reduces dose of topical anesthetic for bronchoscopy

Conventional aerosol techniques were used to determine if inhalation of lidocaine can supplement topical anesthesia applied during bronchoscopy. Aerosols of either saline or lidocaine (50 mg at either 2 or 4% concentrations) were generated by jet nebulizer and administered with or without intermittent positive-pressure breathing. Patients (n = 38) after aerosol inhalation were administered 2% lidocaine (atomized and instilled) for suppression of the gag reflex, control of cough, and airway anesthesia. For five of the patients, prior to bronchoscopy, additional studies with radioaerosols and scintillation scans were accomplished with the same aerosol methodology to demonstrate lung distribution of deposited aerosol. For five patients who received 2% lidocaine aerosol prior to bronchoscopy, the subsequent topical dose of anesthetic required for the procedure was 186 +/- 34 (SEM) mg lidocaine. Nine patients in a control group received saline aerosol and required significantly more anesthetic, i.e., 308 +/- 26 mg; procedures were completed on average within 50 min. The largest difference was in the amount delivered to the upper airway (naris, pharynx, epiglottis, and larynx), i.e., 144 +/- 26 mg for saline control versus 48 +/- 16 mg for lidocaine aerosol protocol. Airways distal to the cords required less anesthesia also, on average, 77 mg for the saline control versus 46 mg for the lidocaine aerosol protocol (p < 0.05). Topical anesthetic dosage data were replicated in 12 additional patients studied by a different bronchoscopist. No additional benefit was afforded by premedication with 4% lidocaine aerosol rather than the 2% aerosol (n = 12). We conclude that aerosol modalities can supplement topical anesthesia during bronchoscopy, primarily by reducing the dose required to anesthetize the upper airway.

Methotrexate treatment of severe asthma in children

Seven children from 3 to 14 years old with chronic steroid-dependent asthma were treated with methotrexate (MTX). Asthma in all of the patients had been poorly controlled for at least 2 years despite the use of oral theophylline and inhaled corticosteroids, cromolyn and albuterol. All presented with significant side effects as a result of chronic systemic steroid therapy. Five patients were atopic and had been unable to tolerate immunotherapy because of systemic reactions. Forced expiratory volume in 1 second and forced expiratory flow, mid-expiratory phase, improved in four patients after 4 to 6 months of treatment with doses of MTX ranging from 7.5 to 17.5 mg/wk. Three patients were able to discontinue their systemic corticosteroids. Laboratory values including complete blood cell count with differential and liver enzymes remained at baseline in all except one patient, who had transient elevation in alanine aminotransferase and aspartate aminotransferase. One patient experienced side effects sufficient to require discontinuation of MTX. It is concluded that MTX is effective for reducing the need for systemic corticosteroids and for improving pulmonary functions in some individuals. The benefits of MTX in this group of severe asthmatics appear to justify the potential risks involved in its use.

Trial of cyclosporin in corticosteroid-dependent chronic severe asthma

The treatment of chronic severe asthma is unsatisfactory for many patients. In a randomised, double-blind, placebo-controlled, crossover trial we have tested whether cyclosporin, which is thought to act primarily by inhibition of T lymphocyte activation, improves lung function in corticosteroid-dependent asthmatics. After a 4-week run-in period, 33 patients with longstanding asthma (mean duration 27 years), and who had required continuous oral corticosteroids for a mean of 9.3 years, were randomised to receive either cyclosporin (initial dose 5 mg/kg per day) or placebo for 12 weeks, crossing over after a 2-week washout period. Mean baseline forced expiratory volume in 1 s (FEV1) was 60.1% of the predicted value. 2 patients failed to complete the protocol and 1 withdrew because of hypertrichosis. Cyclosporin therapy resulted in a mean increase above placebo of 12.0% in morning peak expiratory flow rate (PEFR; p less than 0.004) and 17.6% in FEV1 (p less than 0.001). The frequency of disease exacerbations requiring an increased prednisolone dose was reduced by 48% in patients on cyclosporin compared with placebo (p less than 0.02). Diurnal variation in PEFR decreased by a mean of 27.6% (p = 0.04). Cyclosporin for 12 weeks was well tolerated by this group of chronic asthmatics, in whom the mean whole-blood trough concentration was 152 micrograms/l. These findings provide further evidence of a role for activated T lymphocytes in the pathogenesis of asthma. Specific pharmacological targeting of this cell could form the basis of a novel approach to the treatment of asthma.

Improvement of drug delivery with a breath actuated pressurised aerosol for patients with poor inhaler technique

BACKGROUND The metered dose inhaler is difficult to use correctly, synchronising actuation with inhalation being the most important problem. A breath actuated pressurised inhaler, designed to help patients with poor inhaler technique, was compared with a conventional metered dose inhaler in terms of aerosol deposition and bronchodilator response. METHODS Radioaerosol deposition and bronchodilator response to 100 micrograms salbutamol were measured in 18 asthmatic patients, who inhaled from a conventional metered dose inhaler by their own chosen metered dose inhaler technique, from a conventional metered dose inhaler by a taught metered dose inhaler technique, and from a breath actuated pressured inhaler (Autohaler). RESULTS In the 10 patients who could coordinate actuation and inhalation of the inhaler on their own deposition of aerosol in the lungs and bronchodilator response were equivalent on the three study days. By contrast, in the eight patients who could not coordinate the mean (SEM) percentage of the dose deposited in the lungs with their own inhaler technique (7.2% (3.4%] was substantial lower than those attained by the taught metered dose inhaler technique (22.8% (2.5%] and by Autohaler (20.8% (1.7%]. CONCLUSION Although of little additional benefit to asthmatic patients with good coordination, the Autohaler is potentially a valuable aid to those with poor coordination, and should be considered in preference to a conventional metered dose inhaler in any patient whose inhaler technique is not known to be satisfactory.