Seasonal variability and individual consistency in gray seal (Halichoerus grypus) isotopic niches

Although it is often assumed that individuals in generalist populations are equivalent, recent research indicates that individual dietary specialization can be common in marine predators. Gray seals (Halichoerus grypus (Fabricius, 1791)) were considered locally extinct in United States waters by 1958 but have since recolonized the region. Although considered generalists, less is known about gray seal foraging ecology in the United States. To address this, we used carbon and nitrogen stable isotope analyses to investigate the foraging niches of adult gray seals in Massachusetts, USA. We examined skin, fur, and blood components to investigate seasonal variability and individual consistency in foraging niches, and serially sampled vibrissae to quantify the degree of individual foraging specialization in this population. Our results suggest that seals shift from coastal foraging habitats before molt to offshore habitats after molt, with a coincident shift from higher to lower trophic-level prey. Adult gray seals also exhibited individual consistency in foraging niches independent of population-level shifts and reflect a generalist population composed of individual foraging specialists. These findings serve as a baseline for subsequent research on gray seals in United States waters that could help to determine the mechanisms which promote individual specialization in this population.

Maximal inspiratory pressure and inspiratory muscle endurance time in asthmatic children: reproducibility and relationship with pulmonary function tests

Respiratory muscle strength, assessed by maximal inspiratory mouth pressure (PImax), and endurance, assessed as the length of time a subject could breathe against inspiratory resistance with a target mouth pressure > or = 70% of PI,max (Tlim), were measured in 20 symptomless asthmatic children, in order to assess the reproducibility of such measurements and their relationship to traditional pulmonary function tests or tests of bronchial hyperresponsiveness. After recording lung volumes and bronchial response to methacholine, PI,max and Tlim were measured twice in the same morning, with a 30-minute interval between each experimental trial. Mean (+/-SD) values of PI,max were 72.2 +/- 20.6 cmH2O in the first and 75.8 +/- 22.9 cmH2O in the second trial. Tlim was 154 +/- 65 and 164 +/- 66 seconds in the first and in the second trial respectively. A lack of agreement between different measurements was seen for both PI,max and Tlim. The coefficient of repeatability was 24.8 for PI,max and 92.3 for Tlim. A significant correlation between age and PI,max as well as between body mass index and PI,max were shown; no similar correlation was found for Tlim. No correlation was found between PI,max and Tlim in either of the two successive runs or between either PI,max or Tlim and lung volumes or bronchial response to methacholine. Our study shows that at this time the reproducibility of PI,max or Tlim in children with asthma in remission seems to be poor, although PI,max has a better reproducibility than Tlim. A standardized procedure to measure PI,max, should be obtainable in the near future. This would improve its clinical usefulness since PI,max is the only noninvasive test to assess respiratory muscle strength that can identify subjects at risk to develop respiratory muscle fatigue during an acute asthmatic attack.

Effect of pattern of preceding inspiration on FEV1 in asthmatic children

In adults, both peak expiratory flow (PEF) and forced expiratory volume in one second (FEV1) are significantly influenced by the time course of the inspiration preceding the forced expiration. The aim of this study was to evaluate the effects of three different inspiratory manoeuvres on PEF, FEV1, and forced vital capacity (FVC) in asthmatic children. Twenty five symptomless asthmatic children performed forced expiration preceded by three different inspiratory manoeuvres, which consisted of: a rapid inspiration with a 2 s end-inspiratory breathhold (Manoeuvre No. 1); a rapid inspiration without an end-inspiratory breathhold (Manoeuvre No. 2); and a slow inspiration lasting about 5 s with an end-inspiratory breathhold of at least 4 s (Manoeuvre No. 3). All manoeuvres were performed in a randomly assigned sequence each morning for three consecutive days. In each session, the manoeuvres were repeated three times and the highest value was chosen. Both FVC and FEV1 obtained with Manoeuvre No. 3 were significantly lower than the corresponding values obtained with Manoeuvre Nos. 1 and 2. The mean (SD) FVC values were 2.76 (0.66) L with Manoeuvre No. 1, 2.67 (0.58) L with Manoeuvre No. 2 and 2.52 (0.52) L with Manoeuvre No. 3. The corresponding values of FEV1 were 2.25 (0.53), 2.22 (0.53) and 2.07 (0.44) L, respectively. By contrast, the values of PEF, obtained with a portable peak flow meter, were similar with the three different inspiratory manoeuvres. The results of this study show that in symptomless asthmatic children the preceding inspiratory manoeuvre may influence forced vital capacity and forced expiratory volume in one second. Hence, in order to reduce variability due to interference by physiological factors and so improve reproducibility of pulmonary function tests, the inspiratory manoeuvres must be accurately standardized.

The efficacy and tolerability of fluticasone propionate aqueous nasal spray in children with seasonal allergic rhinitis

Fluticasone propionate aqueous nasal spray (FPANS) contains fluticasone propionate, which is a new topically active glucocorticoid with approximately twice the potency of belcomethasone dipropionate. In this European multicentre study, 143 children with seasonal allergic rhinitis were recruited: 47 received FPANS 100 micrograms once a day (od), 46 received FPANS 200 micrograms od, and 50 patients received placebo od, for 4 weeks. Treatment efficacy was assessed using diary card nasal symptom scores for sneezing, rhinorrhoea, blockage and itching, and eye watering/irritation. Patients receiving FPANS 100 micrograms or FPANS 200 micrograms demonstrated statistically significant improvements in median nasal symptom scores in all the symptoms recorded, when compared with placebo. There were no statistically significant differences between the FPANS 100 micrograms and FPANS 200 micrograms groups in improvement in nasal symptom scores. There was no effect on eye watering/irritation symptoms which could be attributed to either FPANS 100 micrograms or FPANS 200 micrograms when compared with placebo. Use of rescue antihistamine medication was significantly reduced in the FPANS 100 micrograms group when compared with placebo. The adverse events profile was similar in all three treatment groups, and the events reported were generally mild and related to the patients' rhinitis.

Benzyl-benzoate foam: effects on mite allergens in mattress, serum and nasal secretory IgE to Dermatophagoides pteronyssinus, and bronchial hyperreactivity in children with allergic asthma

Home mattresses of 24 asthmatic children with house dust mite allergy were sprayed with either benzyl-benzoate foam or placebo in a double blind fashion, 10 days before the children left the residential house for asthmatic children Istituto Pio XII (located in the Italian Alps in an environment free of mites) and went back to their own home for the Christmas and Easter holidays. A further group of 8 children, whose mattresses received no treatment, was kept as an absolute control. Two days after spraying, benzyl-benzoate or placebo were vacuumed from the mattresses. Acarex test was performed immediately before spraying and at the end of each holiday period of 20 and 10 days, respectively. Bronchial hyperreactivity as well as serum and nasal secretory specific IgE for Dermatophagoides pteronyssinus were assessed in all children immediately before leaving and within 48 hr after returning to the residential house. The results of the study show that sprayed benzyl-benzoate foam was no more effective than placebo in reducing the level of house dust mite recovered from patients' mattresses, or in reducing bronchial hyperreactivity and IgE concentration in serum and nasal secretions.

Effect of beclomethasone dipropionate nasal aerosol on serum markers of bone metabolism in children with seasonal allergic rhinitis

Thirty-nine children with grass pollen hay fever were randomly treated with nasal inhaled beclomethasone dipropionate (BDP) 200 or 400 microg/day or sodium cromoglycate (SCG) 30 mg/day for 2 months during the pollen season. Serum osteocalcin (OC), parathyroid hormone (PTH), total alkaline phosphatase (AP), bone alkaline phosphatase (BAP) and type I collagen telopeptide (ICTP) were measured immediately before, 1 and 2 months after treatment and 1 week after stopping the therapy. No significant changes in OC, PTH, AP, BAP and ICTP serum level occurred within each group. Minor and probably clinically insignificant between group differences were occasionally found. Our study shows that BDP nasal spray has no significant effect on common markers of bone metabolism.

Nedocromil sodium vs. sodium cromoglycate pressurized aerosol in the prevention of bronchoconstriction induced by ultrasonic nebulized distilled water in asthmatic children

To compare the effectiveness of nedocromil sodium (NS) and sodium cromoglycate (SCG), administered by metered dose inhaler (MDI) with a 700 mL holding chamber (Fisonair Fisons UK) in preventing bronchoconstriction induced by inhalation of ultrasonically nebulized distilled water (UNDW), 12 asthmatic children were studied in a randomized, double-blind, placebo-controlled, intrapatient study. Following a baseline challenge with UNDW, the protective effect of NS, SCG, or placebo was evaluated in each subject. Cumulative doses of delivered nebulized water producing a 20% fall in forced expiratory volume in 1 sec (PD20 UNDW) was measured. Mean (+/- SD) PD20 UNDW was 4.83 (+/- 4.84), 10.16 (+/- 7.05), 1.58 (+/- 0.5), and 15.93 (+/- 0.23) respectively, for baseline, and placebo, SCG, and NS-treated groups. A significant (P < 0.05) protection from UNDW induced bronchoconstriction by NS was observed in comparison with placebo, while no such effect was evident when the children were treated with SCG.

Comparison of nedocromil sodium and sodium cromoglycate administered by pressurized aerosol, with and without a spacer device in exercise-induced asthma in children

To compare the effectiveness of nedocromil sodium (NS) and sodium cromoglycate (SCG) administered by metered dose inhaler (MDI) in preventing exercise-induced asthma (EIA), 12 asthmatic children with EIA were studied in a randomized, double-blind, cross-over, placebo-controlled study. NS and SCG were given by MDI alone, and by MDI with a 700 ml spacer device (Fisonair, Fisons, UK), in order to assess the benefit of using such a device. Following a baseline exercise challenge, the protective effect of NS, SCG or placebo was evaluated in each subject. The percentage fall in forced expiratory volume in one second, and percentage protection were measured. NS and SCG provided a significant and comparable protection from EIA, and both were better than placebo. No further improvement was observed after drug administration via the spacer. Both NS and SCG are effective in preventing EIA in children, when administered at the recommended clinical dose, and the use of a spacer for administering the drug provides no advantage if the technique of inhalation is good.

Comparison of nedocromil sodium and sodium cromoglycate administered by pressurized aerosol, with and without a spacer device in exercise-induced asthma in children

To compare the effectiveness of nedocromil sodium (NS) and sodium cromoglycate (SCG) administered by metered dose inhaler (MDI) in preventing exercise-induced asthma (EIA), 12 asthmatic children with EIA were studied in a randomized, double-blind, cross-over, placebo-controlled study. NS and SCG were given by MDI alone, and by MDI with a 700 ml spacer device (Fisonair, Fisons, UK), in order to assess the benefit of using such a device. Following a baseline exercise challenge, the protective effect of NS, SCG or placebo was evaluated in each subject. The percentage fall in forced expiratory volume in one second, and percentage protection were measured. NS and SCG provided a significant and comparable protection from EIA, and both were better than placebo. No further improvement was observed after drug administration via the spacer. Both NS and SCG are effective in preventing EIA in children, when administered at the recommended clinical dose, and the use of a spacer for administering the drug provides no advantage if the technique of inhalation is good.

Vocal cord dysfunction in an asthmatic child: case report

Acute functional narrowing of the glottis frequently leads to an inappropriate diagnosis of asthma. Only 2 cases have been reported of patients with asthma and concomitant vocal cord dysfunction. We present the case of an adolescent boy with asthma, who exhibited a worsening of wheezing and a reduction in peak expiratory flow rate out of proportion to symptoms due to a vocal cord dysfunction.

Reproducibility of late phase pulmonary response to exercise and its relationship to bronchial hyperreactivity in children with chronic asthma

To determine the reproducibility of the delayed response to exercise and its effect on bronchial hyperreactivity, we had 26 asthmatic children perform treadmill exercise challenge on two occasions 1 week apart. Both challenges were preceded by 2 control days and 1 histamine challenge day, and were followed by another histamine challenge day. Peak expiratory flow rate (PEFR) was measured hourly for 12 hours on each control day and for 12 hours after each exercise or histamine challenge. During the first week, five patients showed a late reaction (PEFR change > 15%) after exercise, which was present in only two of them the following week. These two patients, however, also showed a spontaneous fall > 15% of PEFR from baseline during the other control study days. A similar pattern was seen in two other patients who had a late response during the second exercise challenge but not during the first. No significant change occurred in histamine PC-20 FEV1 between before and after the exercise challenges. An apparent late asthmatic response after exercise challenge may represent a within-day fluctuation in pulmonary mechanics that develops spontaneously in children with asthma.

Online bibliographic information: integration into an emerging IAIMS environment

The Medical Library at Yale University has developed an online free-text database containing Current Contents citations. The database was designed to be integrated into an emerging campus-wide information environment. To this end Current Contents at Yale was designed with a user interface familiar to the Yale community, an alerting service based on electronic mail, and search expansion using the National Library of Medicine's Meta-1 metathesaurus.

Perception of bronchoconstriction in chronic asthma

Twenty-nine asthmatic children were studied to assess their ability to detect the severity of their bronchoconstriction. First (STEP 0): each child was asked if he "felt asthma," inviting him to give a self-estimated obstruction score (SEOS) from 0 (no asthma) to 3 (severe asthma) and a baseline FEV1 was recorded. Then (STEP 1): methacholine was administered to all except 9 children with an FEV1 less than 80% of predicted who received saline nebulization and a second SEOS was recorded. Finally: salbutamol aerosol was administered and a third SEOS and FEV1 were obtained (STEP 2). Spearman's correlation coefficients r between SEOS and FEV1 were for the overall population -0.602, -0.517, and -0.104 at STEP 0, STEP 1, and STEP 2, respectively. The r values reduction during the trial can be due either to a decrease of children's concentration during the study or to a real difficulty in recognizing repeated changes in airway status. Some children tend to underestimate their bronchospasm. For these patients an accurate assessment of the severity of the bronchoconstriction requires an objective measurement during acute changes in asthmatic children.

Inhibition of different dosages of oxatomide or placebo on skin prick test and nasal allergen provocation

In this two-stage, double-blind study, we evaluated the effects of different dosages of oxatomide (1 and 2 mg/kg/day) on nasal provocation and skin reaction wheal induced by grass-pollen challenge. Children with a positive history of allergic rhinoconjunctivitis and positive responses to skin prick test and nasal provocation test to grass pollen were studied out of season. The results obtained with 1 mg/kg/day of oxatomide demonstrated no significant difference in wheal areas and nasal secretion induced by allergen challenge between treated and untreated patients. The administration of 2 mg/kg/day demonstrated a significant suppression in wheal reaction and nasal secretion induced by specific challenge.

Effect of inhaled beclomethasone dipropionate on bronchial hyperreactivity in asthmatic children during maximal allergen exposure

In this double blind study we evaluated the effect of a 2 months long treatment with inhaled beclomethasone dipropionate (300 micrograms/day) on methacholine responses in asthmatic children, during a period of maximal allergen exposure. Baseline values of methacholine PC20-FEV1 were 0.66 +/- 0.22 mg/mL (mean +/- SEM) in 10 children treated with the active drug and 0.78 +/- 0.21 mg/mL in 10 children treated with placebo. After 1 month of treatment PC20-FEV1 was 1.91 +/- 0.64 and 0.80 +/- 0.33 mg/mL, respectively, in the groups treated with beclomethasone versus placebo. A statistically significant reduction in bronchial hyperreactivity (PC20-FEV1, 5.49 +/- 1.86 mg/mL) but no systemic side effects were observed after 2 months of treatment with beclomethasone dipropionate. This is compared with a PC20-FEV1 of 1.38 +/- 0.52 mg/mL in the placebo group. The results confirm the effect of inhaled corticosteroids in reducing bronchial hyperreactivity, even during a period of maximal allergen exposure.

Double-blind evaluation of effectiveness and safety of flunisolide aerosol for treatment of bronchial asthma in children

A double-blind study was carried out in 20 asthmatic children in order to evaluate the therapeutic efficacy and safety of inhaled corticosteroid flunisolide. 0.5 mg of the drug was administered by a jet nebulizer twice daily for 2 months. Respiratory symptoms, pulmonary function values and methacholine PC20-FEV1 were evaluated, as also morning cortisol levels, plasma cortisol increase after ACTH test, and 24-h urinary cortisol excretion. The data obtained show the efficacy of the drug in reducing symptoms. No significant difference was observed in pulmonary function values and in bronchial reactivity results between the two groups. No effect of flunisolide was observed on hypothalamic-pituitary-adrenal function. This study confirms the efficacy and safety of flunisolide (0.5 mg b.i.d.) in the treatment of asthmatic children.

Metabisulfite oral challenge: incidence of adverse responses in chronic childhood asthma and its relationship with bronchial hyperreactivity

Fifty-six children with chronic asthma, 6 to 14 years of age, were studied to evaluate bronchoconstrictive airway responses after ingestion of varying doses of potassium bisulfite administered in one occasion in capsule and in another occasion in solution. With methacholine challenge before and after metabisulfite (MBS) provocation, the relationship of bronchoconstrictive responses and bronchial hyperreactivity was evaluated. Positive bronchoconstrictive responses were observed in only four children after the ingestion of a maximum dose of MBS in capsule and in two children after the ingestion of different doses of MBS solution. A high reactivity to methacholine challenge was present in all the reactive children. After MBS challenge, no additional changes in bronchial reactivity were observed either in the reactors or nonreactors.

Efficacy and duration of action of oral procaterol in asthmatic children after single administration of different dosages

A double-blind crossover study was performed to evaluate the bronchodilating effect of different single doses of procaterol (less than 0.5 micrograms/kg, 1.5 micrograms/kg, and placebo) orally administered. Sixteen asthmatic children, age 6-12 years, participated in the trial. Pulmonary function, heart rate, blood pressure, and tremor were evaluated at 30, 60, 90, and 120 min and then hourly for 8 hours after administration. All three doses were therapeutically effective. The 1.5 micrograms/kg dose produced a more sustained bronchodilatation effect, but was also associated with an increase in the incidence of tremors. The 0.5 micrograms/kg dosage may, however, be a good starting dose because it assures a reasonable risk/benefit ratio.

Theophylline levels after single daily and divided dosing of a once-a-day theophylline preparation in asthmatic children

Twelve children with chronic asthma were treated with a single dose of sustained-release theophylline once-a-day taken after supper at 9 PM. During the steady-state period after 15 days of treatment, serum theophylline levels were measured one and two hours after dosing and then every two hours until 9 PM the following day. The peak concentration (mean +/- SD) of serum theophylline (20.9 +/- 6.5 micrograms/mL) was observed eight hours after dosing while the through concentration (4.34 +/- 2.62 micrograms/mL) was measured 24 hours after dosing; the percent fluctuation (mean +/- SD) was 966.45 +/- 1105.55%. Another 15 children were treated with the same preparation administered at 8 AM after breakfast and at 8 PM after supper. Serum samples for theophylline concentration were obtained immediately before dosing at 8 AM and then every two hours for the following 12 hours. The mean theophylline level observed immediately before dosing at 8 AM was 10.16 +/- 3.84 micrograms/mL while the mean level at 8 PM was 9.39 +/- 4.77 micrograms/mL. The peak serum level was 13.07 +/- 5.13 micrograms/mL at 2 PM, while the trough was 9.31 +/- 3.71 micrograms/mL at 10 AM, with a percent fluctuation of 155.21 +/- 147.95%. Few side effects were seen in both groups. The results of our study clearly demonstrated that in children the percent fluctuation and peak-trough differences are far greater with once daily than with twice daily dosing and this should be considered when planning theophylline treatment in asthmatic children. The administration of a once-a-day preparation every 8-12 hours can however result in overlapping absorption patterns.

Changes in bronchial reactivity in asthmatic children after treatment with beclomethasone alone or in association with salbutamol

Airway inflammation is consistently present in patients with severe asthma. The combination of inhaled steroids and bronchodilators may be useful both for treating symptoms and improving the underlying inflammatory condition. We have compared the effect of beclomethasone dipropionate (BDP) combined with salbutamol (S), BDP alone, and placebo, on the severity of bronchial responsiveness in 30 children with allergic asthma during the period of specific allergen exposure. In children treated with BDP alone, PC20-FEV1 methacholine was 0.66 +/- 0.54 at the beginning and 1.91 +/- 2.11 at the end of the study period (p greater than 0.05). In children treated with BDP + S PC20, methacholine was 1.21 +/- 1.43 at the beginning and 4.22 +/- 3.88 at the end of the study (p less than 0.05). The group of children treated with placebo had a PC20-FEV1 methacholine of 0.79 +/- 0.61 at the beginning of the study and 0.80 +/- 0.46 at the end of the study. The results of the present study show that maintenance treatment with inhaled beclomethasone combined with salbutamol may lead to greater improvement in bronchial hyperreactivity than treatment with inhaled beclomethasone dipropionate alone.

Effect of food on the bioavailability of a slow-release theophylline formulation

A study was conducted in two groups of healthy volunteers to assess whether the time of administration (10 min before the meal versus 60 min after the meal) influences the pharmacokinetics and absorption kinetics of a slow-release theophylline product (Teonova). In the first group (Group A, n = 10), the drug was given in a paired-sample design as a single dose of 600 mg before and after breakfast with an interval of at least 1 week between the two administrations. In the second group (Group B, n = 10), Teonova was given by the same study design before and after dinner. In all cases, time curves of theophylline plasma levels were determined by collecting serial blood samples 24 h after dosing and analysed pharmacokinetically through model-independent methods. In Group A, curves obtained before and after the meal were fully superimposable, and no difference was found between the pharmacokinetic parameters determined in either condition. The same result was obtained in Group B. Our results indicate that, after single dose, the two different times of administration that we tested were equivalent in pharmacokinetic terms.

Comparison of the effects of inhaled calcium antagonist verapamil, sodium cromoglycate and ipratropium bromide on exercise-induced bronchoconstriction in children with asthma

Fifteen children with exercise-induced asthma (EIA) participated in a double-blind trial comparing the protective effects of inhaled sodium cromoglycate (20 mg/2 ml), ipratropium bromide (500 micrograms/2 ml) and verapamil (5 mg/2 ml). Saline was used as control. There was no significant difference in base line pulmonary function before and after the administration of each agent. After exercise the maximal percentage fall in the forced expiratory volume in 1 s (FEV-1) (means and SD) were 40.9 +/- 17.2 after inhalation of saline, 15.3 +/- 11.7 after sodium cromoglycate, 36.2 +/- 21.4 after verapamil and 21.7 +/- 17.7 after ipratropium bromide. The inhibitory effects of sodium cromoglycate and ipratropium bromide were significant whereas verapamil failed to produce any effect. To see if a double dose of verapamil is more effective, nine different children with EIA were provoked by the same standardized treadmill running after giving a placebo (4 ml saline) and after verapamil (10 mg in 4 ml). Despite the double dose, again verapamil was ineffective even though the protection index doubled that obtained with the lower dose. The results suggest that the calcium antagonist (verapamil) had almost no effect on the prevention of EIA in the children studied.

Bronchodilating activity of oral clenbuterol in asthmatic children after single administration of different dosages

The dose-response activity of clenbuterol, a new long-acting beta 2-agonist, was evaluated in 12 children aged 5 to 11 years with moderate to severe asthma. The study was a double-blind cross-over comparison of three oral dose levels: 0.5, 1.0, and 1.5 micrograms/kg and placebo all in the form of syrup. Pulmonary function, heart rate, blood pressure, and tremor were evaluated at 30, 60, 90, and 120 min, then hourly for 8 hr, following the ingestion of the drug. The bronchodilating effect of clenbuterol, evaluated as percentage changes in expiratory flow rates was significantly different from placebo. The overall fall-off in the effect of 1.0 micrograms/kg and 1.5 micrograms/kg doses after 8 hr was small. The results of the 1.0 micrograms/kg dose often overlapped those of the 1.5 micrograms/kg dose, suggesting that a single 1.0 micrograms/kg dose of clenbuterol is most advisable in children, assuring the most favorable risk/benefit ratio. Even the highest dose of clenbuterol caused only a marginal increase in tremor, not statistically different from that induced by placebo.

Oral clenbuterol and procaterol. A double-blind comparison of bronchodilator effects in children with chronic asthma

In a double-blind crossover study, clenbuterol at a dose of 0.75 micrograms/kg, procaterol at a dose of 1.5 micrograms/kg, and placebo, all administered orally, were compared for bronchodilation efficacy. Twelve children aged from 6 to 13 years, with moderate to severe asthma, participated in the trial. Pulmonary function, heart rate, blood pressure, and tremor were evaluated at 30, 60, 90, and 120 minutes and then hourly for 8 hours after administration. Both clenbuterol and procaterol induced a significant change over their baseline values for all the pulmonary function parameters considered. For clenbuterol, the same was also observed in comparison with placebo, while for procaterol this was true only for FEV1 and FEF25-75, while no difference resulted from FVC and PEF. Mild and transient tremor was the only side effect observed. Oral clenbuterol and procaterol were both demonstrated to be safe and effective. However, at the doses studied, clenbuterol had a significantly higher bronchodilator activity lasting up to 8 hours.

Effects of different dosages of the calcium antagonist verapamil in exercise- and methacholine-induced bronchospasm in children with chronic asthma

The protective effect of 5 mg/2 ml and 10 mg/4 ml of the calcium antagonist verapamil on methacholine challenge and exercise were evaluated in two groups of asthmatic children. Saline solution was used as placebo. No significant differences were seen in baseline pulmonary function in and within groups. There was a minimal but significant bronchodilation 30 minutes after inhalation of verapamil 5 mg/2 ml. The drug did not reduce methacholine sensitivity at any dosage. After exercise, verapamil 5 mg/2 ml showed a significant change in the maximum percentage drop in forced expiratory volume in 1 second (FEV1) compared with placebo. This was not the case for the group treated with a double dosage. At this time, there is no evidence for a major role of verapamil in the treatment of childhood asthma.