Analysis of induced sputum before and after withdrawal of treatment with inhaled corticosteroids in asthmatic patients

To assess whether sputum eosinophilia predicts the recurrence of asthma symptoms after withdrawal of therapy in moderate stable asthmatics on low-dose inhaled corticosteroids. Randomized, double-blind, placebo-controlled study involving 30 subjects with stable asthma, asymptomatic, with low PEF variability measured over two run-in weeks, on treatment with low-dose inhaled beclomethasone dipropionate (BDP, 250 microgram b.i.d. in the last 3 months). At the end of the run-in, all patients underwent a methacholine challenge test and sputum induction (T1). They then stopped therapy and received either placebo (20 subjects, study group) or BDP at the same dose as in the previous 3 months (10 subjects, control group). They continued to monitor PEF and symptom score for 3 months, or until asthma symptoms recurred (diurnal and nocturnal symptom score >/=2 on two consecutive days). At the end of the study (T2), i.e., either within 5 days from the beginning of asthma symptoms or after 3 months in subjects without recurrence of asthma symptoms, all subjects repeated the methacholine challenge test and sputum induction. In the placebo-treated group, sputum eosinophils at T1 were significantly higher in subjects who subsequently developed recurrence of asthma symptoms (n = 7) after cessation of treatment than in subjects who remained asymptomatic for 3 months (8.2% [0-56.6] vs 0.9% [0-11], P < 0.05). At the time of recurrence of asthma symptoms, sputum eosinophil percentages significantly increased (from 8.2% [0-56.6] to 16.6% [5.8-73.6], P < 0.05). The positive predictive value of sputum eosinophils for the recurrence of asthma symptoms was 71%, while the negative predicting value was 84%. In the BDP-treated control group, none of the subjects experienced recurrence of asthma symptoms, and sputum eosinophil percentages measured at the beginning (T1) and at the end (T2) of the study were similar. Sputum eosinophil percentages may vary over a wide range in asthmatic subjects, although regularly treated and apparently well controlled. However, high sputum eosinophil percentages are related to early recurrence of asthma symptoms after cessation of inhaled corticosteroids.

Natural exposure to pollen reduces the threshold but does not change the pattern of response to the allergen in allergic subjects

It is known that exposure to seasonal allergen in sensitized asthmatics increases non-specific bronchial responsiveness, but it is controversial if exposure to seasonal allergen influences the presence and the severity of the late asthmatic response (LAR) to allergen. Fifteen asthmatic subjects sensitized to grass pollen performed a specific bronchial provocative test (sBPT) with Phleum pratensis extract before and during the pollen season. Changes of methacholine were also assessed. Allergen PD20FEV1 significantly decreased during the pollen season with respect to outside (allergen PD20FEV1, geometric mean: 0.10 vs. 0.23 biological units; P < 0.05), but the pattern of specific airway response did not change. Particularly, a consistent LAR was observed in three subjects outside the pollen season and in two subjects during the pollen season. Seven subjects with isolated early asthmatic response (EAR) outside the season did not show LAR after allergen inhalation during the pollen season. However, four of five subjects with slight LAR outside the pollen season (deltaFEV1% between 15 and 20%) lost LAR during season. Methacholine sensitivity increased slightly but significantly from outside to during the pollen season. This increase was greater in subjects with LAR outside the pollen season. The natural exposure to pollen induces an increase in bronchial sensitivity to allergen in sensitized subjects, but it does not induce LAR in subjects without LAR outside the pollen season.

A simple bacterial index for relative water quality: preliminary application in the Orbetello lagoon (Tuscany, Italy)

A simplified fingerprint, elaborated upon heterotrophic bacterial charge and conventional faecal coliforms (FCs) was used to measure the relative quality of the waters in the western basin of the Orbetello lagoon (Tuscany, Italy). Different bacteriological parameters were combined, after standardisation, obtaining "iso-quality" lines. The-final image of the lagoon exhibits different pollution levels, with a relative minimum in the central area.

Reproducibility of early and late asthmatic responses to allergen challenge in a large group of asthmatics

The specific bronchial provocative test (sBPT) coupled with allergen is used to investigate asthma. Very few studies have examined the reproducibility of responses to allergen challenge. The aim of this study was to measure the reproducibility of PD20FEV1 allergen and late asthmatic response (LAR) in 53 asthmatics and to relate the reproducibility to the time interval between two allergen challenges. Fifty-three atopic asthmatics performed two allergen challenges not less than 2 and not more than 26 weeks apart. Randomly, 19 subjects were assigned to a short-interval group (14-35 days between the two tests) and 34 to a long-interval group (40-180 days). In each challenge, the PD20FEV1 was sought for and the maximum % fall in FEV1 from 3 to 7 h after the allergen challenge was evaluated as a measurement of magnitude of the LAR. High intraclass correlation coefficients (R(I)) were found for both PD20FEV1 (R(I) = 0.78) and LAR (R(I) = 0.77) in all subjects. PD20FEV1 allergen showed a high R(I) in the long-interval group (R(I) = 0.80), but a low R(I) in the short-interval group (R(I) = 0.63). In contrast LAR showed a lower R(I) in the long-interval group (R(I) = 0.68) than in the short-interval group (R(I) = 0.77). Moreover, the R(I) for PD20FEV1 was particularly low in subjects with a dual pattern to the allergen challenge and a short interval between the two allergen challenges. Our study confirmed that asthmatic responses induced by allergen challenge have a good reproducibility. Moreover, we have demonstrated that the interval between two allergen challenges can determine a change in reproducibility in asthmatic responses induced by allergen challenge.

The protective effect of salbutamol inhaled using different devices on methacholine bronchoconstriction

STUDY OBJECTIVE

To determine the protective effect of salbutamol, 100 microg, inhaled by different devices (pressurized metered-dose inhaler [pMDI; Ventolin; GlaxoWellcome; Greenford, UK], pMDI + spacer [Volumatic; GlaxoWellcome], or breath-activated pMDI [Autohaler; 3M Pharmaceuticals; St. Paul, MN]) on bronchoconstriction induced by methacholine.

DESIGN

Randomized, double-blind, cross-over, placebo-controlled study.

PATIENTS

Eighteen subjects with stable, moderate asthma, asymptomatic, receiving regular treatment with salmeterol, 50 microg bid, and inhaled beclomethasone dipropionate, 250 microg bid, in the last 6 months, with high hyperreactivity to methacholine (baseline provocative dose of methacholine causing a 20% fall in FEV(1) [PD(20)] geometric mean [GM], 0.071 mg). Subjects were classified into two groups: subjects with incorrect (n = 5) pMDI inhalation technique, and subjects with correct (n = 13) inhalation technique.

METHODS AND MEASUREMENTS

After cessation of therapy for 3 days, all subjects underwent four methacholine challenge tests, each test 1 week apart, each time 15 min after inhalation of salbutamol, 100 microg (via pMDI, pMDI + spacer, or Autohaler), or placebo. The protective effect on methacholine challenge test was evaluated as the change in the PD(20), and expressed in terms of doubling doses of methacholine in comparison with placebo treatment.

RESULTS

The PD(20) was significantly higher after salbutamol inhalation than after placebo inhalation, but no significant difference was observed among the three different inhalation techniques. Only when salbutamol was inhaled via pMDI + spacer, PD(20) was slightly but not significantly higher (pMDI GM, 0.454 mg; pMDI + spacer GM, 0.559 mg; and Autohaler GM, 0.372 mg; not significant [NS]) than other inhalation techniques. Similar results (mean +/-SEM) were obtained with doubling doses of methacholine (pMDI, 2 +/- 0.47; pMDI + spacer, 3 +/- 0.35; and Autohaler, 2.4 +/- 0.40; NS). No significant difference was found among techniques when subjects with correct or incorrect inhalation technique were separately considered.

CONCLUSIONS

Our data show that the protective effect of salbutamol, 100 microg, on methacholine-induced bronchoconstriction is not affected by the different inhalation techniques, although inhalation via pMDI + spacer tends to improve the bronchoprotective ability of salbutamol. These data confirm the clinical efficacy of salbutamol, whatever the device, and the patient's inhalation technique.

Geothermal power plants at Mt. Amiata (Tuscany-Italy): mercury and hydrogen sulphide deposition revealed by vegetation

At Mt. Amiata (Italy) geothermal energy is used, since 1969, to generate electricity in five plants with a nominal capacity of 88 MW. Anomalous levels of mercury characterise geothermal fluids of Mt. Amiata, an area renowned for its vast cinnabar deposits and for the mercury production carried out in the past. Mercury emission rates range from 300 to 400 g/h, or 3-4 g/h per MW electrical installed capacity. These emissions are coupled with a release of 7-8 kg/(h MW) of hydrogen sulphide (H2S). Mercury is discharged as Hg0 gaseous species and reaches the atmosphere with the non-condensable gas fraction. In this fraction, CO, is the major component (94-98%), H2S is around 1% and mercury concentration is as high as 1-10 mg/Nm3. Leaves of a spontaneous grass (Avena sterilis), at the end of the vegetative cycle, were used as mercury bioconcentrators to map deposition near geothermal power plants and to calculate the corresponding average levels of Hg0 in the air. Direct measurements of mercury and hydrogen sulphide vapours in the air reached by power plant emissions showed a ratio of about 1-2000. This ratio was applied to calculate average levels of hydrogen sulphide starting from mercury deposition mapping: typical concentrations of mercury and hydrogen sulphide were of the order of 10-20 ng/m3 and 20-40 microg/m3, respectively.

Comparison of different long-term asthma treatments in subjects with mild-to-moderate asthma

In order to compare the efficacy of different asthma treatment in subjects with mild-to-moderate asthma, three groups of 11 patients were treated with nedocromil sodium (NS), beclomethasone dipropionate (BDP) and beclomethasone dipropionate plus salmeterol (BDP + S) in an open, randomized study. Symptom score, peak expiratory flow (PEF) maximal amplitude, forced expiratory volume in one second (FEV1), and methacholine reactivity were measured at the baseline and at intervals of 3 months up to 12 months. After 3 months, symptoms reduced significantly in all treatment groups, while PEF variability improved in BDP and BDP + S groups; FEV1 and bronchial responsiveness to methacholine were significantly improved in comparison with baseline value in the BDP + S group only. No significant difference was observed after 6 and 12 months of treatment in PEF variability, FEV1 or bronchial hyperreactivity in the NS group compared with baseline values, while a significant difference was observed in symptom score. BDP group showed a significant improvement in FEV1 and bronchial reactivity to methacholine after 6 and 12 months of treatment. In the BDP + S group, the improvement in symptoms and pulmonary function persisted until the end of the study. In conclusion, the combination of beclomethasone dipropionate and salmeterol improved pulmonary function and bronchial reactivity earlier than beclomethasone dipropionate alone, while nedocromil sodium improved symptoms but not pulmonary function. Assuming that bronchial reactivity could be an indirect measurement of airway inflammation, overtreatment of asthma in relationship with the classification of asthma severity of the International Guidelines could improve both airway inflammation and the prognosis of airway obstruction.

Effect of a single dose of salmeterol on the increase in airway eosinophils induced by allergen challenge in asthmatic subjects

BACKGROUND

The long acting beta2 agonist salmeterol is very effective in preventing asthmatic responses to specific stimuli, and this effect could theoretically be due to some anti-inflammatory property in addition to bronchodilator property.

METHODS

The protective effect of a single dose of salmeterol (50 microg) on allergen induced early and late responses and on the associated airway inflammation was investigated in a double blind, placebo controlled, crossover study in 11 atopic asthmatic subjects. Eosinophil percentages and concentrations of eosinophil cationic protein (ECP) in peripheral blood and in hypertonic saline induced sputum were measured 24 hours after allergen inhalation.

RESULTS

Salmeterol effectively inhibited both early and late asthmatic responses in comparison with placebo. Salmeterol also inhibited the increase in the percentage of eosinophils in the sputum 24 hours after allergen inhalation (median (range) baseline 6% (1-36), after placebo 31% (5-75), after salmeterol 12% (1-63)). However, the increase in both sputum and serum ECP concentrations 24 hours after allergen challenge was not affected by pretreatment with salmeterol.

CONCLUSIONS

A single dose of salmeterol inhibits the allergen induced airway responses and the increase in sputum eosinophils after allergen challenge.

Salbutamol pretreatment does not change eosinophil percentage and eosinophilic cationic protein concentration in hypertonic saline-induced sputum in asthmatic subjects

BACKGROUND

Sputum induction by inhalation of hypertonic saline (HS) is usually preceded by beta2-agonist pretreatment, to prevent severe bronchoconstriction.

OBJECTIVE

To evaluate whether salbutamol pretreatment may influence cell counts and concentrations of soluble mediators in induced sputum.

METHODS

We studied 22 patients who randomly underwent HS sputum induction after pretreatment with either 200 microg salbutamol or placebo. Sputum was induced by means of HS inhalation (3, 4, 5% NaCl, 10 min each), measuring FEV1 every 5 min until it fell >/= 20% from baseline. Collected sputum was diluted 1 : 1 with 0.1% DTT, incubated at 37 degrees C for 20 min, and total and differential cell counts were measured. ECP and histamine levels were measured in the supernatant.

RESULTS

Sputum volume, percentages of inflammatory cells, squamous cell counts and quality of the slides were not different after the two pretreatments, while sputum total inflammatory cells after salbutamol tended to be higher than after placebo (8.3 [1-41] 10(6) vs 6.3[0.2-40] x10(6); P = 0.09). Eosinophilic cationic protein (ECP) did not significantly change (260 [8-900] microg/L after salbutamol vs 200 [8-800] microg/L, n = 19), while histamine levels tended to be lower after salbutamol (140.9 [39.9-236.5] nm) than after placebo (190.4 [72. 2-322.6] nm, P = 0.09, n = 17). The airway response to HS inhalation was significantly greater after placebo and the duration of the test was significantly different (median: 15 min after placebo and 30 min after salbutamol). Similar results were obtained when patients who differed for more than 15 min in the duration of HS-inhalation in the two tests were selected (n = 11).

CONCLUSION

Salbutamol pretreatment reduces the severity of bronchoconstriction induced by HS inhalation without significantly affecting the percentages of inflammatory cells and the levels of soluble mediators in induced sputum.

Inhaled beclomethasone dipropionate reverts tolerance to the protective effect of salmeterol on allergen challenge

STUDY OBJECTIVE

One week of regular treatment with salmeterol can induce tolerance to the protective effect of a beta2-agonist on early airway response to allergen (EAR). The objective was to assess whether inhaled corticosteroids revert tolerance to salmeterol.

STUDY DESIGN

The study had a randomized, double-blind, placebo-controlled design.

PATIENTS AND METHODS

Twelve subjects with mild allergic asthma and positive result of specific bronchial provocation test (sBPT) to allergen underwent three sBPTs, separated by 1 week. sBPT was done in all subjects after a single dose (T1) and after 1 week of regular treatment with inhaled salmeterol (50 microg bid) (T2) in order to induce tolerance. Subjects were then randomized to receive either the same dose of salmeterol + beclomethasone dipropionate (BDP, 500 microg bid) (group 1, n = 6) or placebo + BDP (group 2, n = 6) for 1 week before sBPT (T3).

RESULTS

After a single dose of salmeterol (T1), all subjects were protected against EAR, whereas after 1 week of regular treatment, the protective effect of salmeterol was totally or partially lost (T2). Maximum FEV1 percent fall (MaxdeltaFEV1%) after allergen inhalation was significantly higher at T2 than at T1. All subjects except one of group 1 were protected against EAR after salmeterol + BDP (T3), and MaxdeltaFEV1% at T3 (median, 12%; range, 4 to 6%) was significantly lower than T2 (median, 22%; range, 12 to 43%; p < 0.05 by Wilcoxon test). Subjects of group 2 did not show any significant protection against EAR after placebo + BDP treatment (T3) MaxdeltaFEV1% at T2 (median, 31%; range, 9 to 40%) and T3 (median, 31%; range, 3 to 42%; not significant).

CONCLUSIONS

In conclusion, the addition of inhaled BDP partially restored the bronchoprotective effect of salmeterol on allergen challenge that was lost after 1 week of regular treatment with salmeterol alone. This ability of BDP in reverting tolerance cannot be ascribed to a direct effect of corticosteroids per se on allergen challenge in this group of asthmatics.

Airway inflammatory response to ozone in subjects with different asthma severity

The aim of this study was to evaluate whether ozone exposure induces a similar airway inflammatory response in subjects with different degrees of asthma severity. Two groups of asthmatic subjects were studied: seven with intermittent mild asthma not requiring regular treatment (group A); and seven with persistent mild asthma requiring regular treatment with inhaled corticosteroids and long-acting beta2-agonists (group B). All subjects were exposed, in a randomized cross-over design, to air or O3 (0.26 parts per million (ppm) for 2 h with intermittent exercise); subjects in group B withdrew from regular treatment 72 h before each exposure. Before the exposure, and 1 and 2 h after the beginning of the exposure they performed a pulmonary function test, and a questionnaire was completed to obtain a total symptom score (TSS). Six hours after the end of the exposure, hypertonic saline (HS) sputum induction was conducted. Sputum cell percentages, eosinophil cationic protein (ECP) and interleukin (IL)-8 concentrations in the sputum supernatant were measured. TSS significantly increased and forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) significantly decreased after O3 exposure in comparison with air exposure in group A, whereas no changes were observed in group B except for a significant decrement of FEV1 2 h after the beginning of O3 exposure. Sputum neutrophil percentage was significantly higher after O3 exposure than after air exposure in both groups (Group A: 70.2% (28-87) versus 26.6% (8.6-73.2); Group B: 62.1% (25-82.4) versus 27.9% (14.4-54)). IL-8 was higher in sputum supernatant collected 6 h after O3 exposure than after air, only in group A. No change due to O3 has been found in sputum eosinophil percentage and ECP concentration in both groups. In conclusion, the degree of airway response to a short-term exposure to ozone is different in subjects with asthma of different severity. The available data do not allow elucidation of whether this difference depends on the severity of the disease or on the regular anti-inflammatory treatment.

Comparison between eosinophilic markers in induced sputum and blood in asthmatic patients

BACKGROUND

The usefulness and safety of the analysis of blood inflammatory markers in asthma are widely recognized. Recently, the analysis of induced sputum has been proposed as a safe, non-invasive tool in the study of airway inflammation in asthma.

OBJECTIVE

Our aim was to test whether sputum analysis is more useful than blood analysis in the evaluation of airway inflammation in untreated and treated asthmatic patients.

METHODS

Twelve untreated patients with mild to moderate asthma underwent a methacholine challenge test, sputum induction and blood sampling. A group of 14 normal subjects was also evaluated for baseline comparison. The same evaluation was repeated after 3 months of budesonide treatment. Before and after treatment, we tested the relationship of eosinophilic markers in induced sputum and blood with clinical and functional data. We also compared eosinophilic markers in induced sputum with the same markers in blood.

RESULTS

Untreated patients showed a significant relationship between sputum eosinophils and symptom score, and between sputum eosinophilic cationic protein and symptom score, FEV1 and PD20FEV1. No relationship between blood eosinophilic markers and clinical or functional data was observed. In budesonide-treated patients, both sputum and blood eosinophils were significantly lower than in untreated patients, but eosinophil decrease was greater in sputum than in blood. Sputum eosinophilic proteins were also significantly lower in treated patients, whereas serum eosinophilic proteins were low at baseline and remained unchanged after treatment. Sputum eosinophilic markers were lower in normal subjects than in both untreated and treated patients, while blood eosinophils, but not serum eosinophilic cationic protein, were lower in normals than in untreated patients.

CONCLUSIONS

The analysis of induced sputum is more useful than the analysis of blood in the evaluation of asthma severity and of the effect of glucocorticoid treatment in patients with mild to moderate asthma.

Leukocyte counts in hypertonic saline-induced sputum in subjects with occupational asthma

We measured markers of eosinophilic inflammation in the blood and in the sputum induced by hypertonic saline (HS) inhalation of 24 subjects with occupational asthma who were still exposed to high molecular weight compounds (HMWCs, n = 8) or to low molecular weight compounds (LMWCs, n = 16); all subjects were symptomatic and showed bronchial hyperresponsiveness to methacholine at the time of study. Sputum cell counts were also measured in 14 normal subjects and in 24 subjects with non-occupational asthma with asthma severity similar to that of occupational asthmatics. Both occupational and non-occupational asthmatic subjects showed higher neutrophil percentages in HS-induced sputum than normal subjects, asthmatics with LMWC-induced asthma showing the highest values. Eosinophil percentages in HS-induced sputum were higher in non-occupational asthmatics and in asthmatics with HMWC-induced asthma than in normal subjects and in subjects with occupational asthma due to LMWCs. No difference in bronchial responsiveness, peak expiratory flow variability and serum eosinophil cationic protein (ECP) levels were observed among the different asthma groups. Although sputum eosinophil percentages significantly correlated with blood eosinophil percentages, sputum allowed the detection of a higher number of subjects with eosinophilic inflammation than blood. Serum ECP levels were normal in most asthmatic subjects. A significant correlation between sputum eosinophil percentages and bronchial hyperresponsiveness to HS was observed. Despite a similar degree of functional abnormalities, subjects with asthma due to LMWCs and still exposed to the occupational sensitizer showed a lower degree of eosinophilic inflammation and a higher degree of neutrophilic inflammation in the airways than subjects with occupational asthma due to HMWCs or non-occupational asthmatics. Furthermore, sputum eosinophil counts detect, better than blood indices, the degree of airway inflammation in both occupational and non-occupational asthma.

Sister chromatid exchange and micronucleus frequency in human lymphocytes of 1,650 subjects in an Italian population: I. Contribution of methodological factors

The influence of several methodological factors on mean values of sister chromatid exchanges (SCEs) and micronuclei (MN) in peripheral lymphocytes of 1,650 subjects was analyzed. Donors belonged to a general healthy population living in Pisa and in two nearby small cities: Cascina and Navacchio (Ca-Na). Blood samples were collected over a period of 29 months and processed in three different laboratories of the some institute. Slides were analyzed by several scorers. Our data showed that lymphocyte proliferation indexes (PIs) and baseline mean values of SCEs were affected mainly by sampling period. This factor accounted for a percentage ranging from roughly 10% (Pisa) to 20% (Ca-Na) of total SCE variance and from roughly 10% (Pisa) to 13% (Ca-Na) of total PIs variance. A marginal effect was attributable to the different laboratories involved (maximum 3% for SCEs and 7% for PIs). The sampling period variable included many sources of variability such as culture media batches, fetal calf serum, PHA, BrdUrd, and seasonality. MN counts revealed a more marked dependence on processing laboratories. This factor accounted for a percentage of roughly 10% (Pisa and Ca-Na) of total variance, while the sampling period was marginally effective (about 1-4% of total variability). Because laboratories were equipped and supplied with the same materials and consumables and technicians were rotated constantly, the only variable ascertained was represented by the three different models of CO2 incubators used for lymphocyte culturing. When "month" and "incubator" variables were considered jointly, experimental variability accounted for 15-20% of total variance, both for PIs and mean values SCEs and MN. The variability due to slide scoring was reduced by assigning each slide to five different scorers and matching low with high scorers in each group. Present data show that when the study is performed under these controlled conditions, about 20% of total interdonor variability can be explained by experimental or seasonal factors.

Comparison between peak expiratory flow and forced expiratory volume in one second (FEV1) during bronchoconstriction induced by different stimuli

To evaluate the sensitivity of peak expiratory flow (PEF), obtained by portable peak flow meter, in detecting mild changes in airway caliber as assessed by forced expiratory volume in 1 sec (FEV1), we studied 184 subjects who underwent different bronchial challenge tests for suspected bronchial asthma. We measured FEV1 and PEF during bronchoconstriction induced by different stimuli: allergen, methacholine, toluene diisocyanate vapors, exercise, or distilled water inhalation; a total of 186 tests were examined. Before and at different times after challenge, FEV1 was measured, and immediately after, PEF was obtained by Mini-Wright or Assess Peak Flow Meter; each time FEV1 and PEF were taken as the best of three satisfactory tracings. The median FEV1 change from baseline value of all steps in the different challenge tests was 7.5% (range: 0-66%). The correlation coefficients between FEV1 and PEF percent changes in different challenge tests were low (Spearman's p: 0.27-0.69), with high scattering of the data. The concordance between classes of percent changes in FEV1 and PEF was also low (Cohen's weighted kappa: 0.28-0.42). In subjects with a FEV1 fall > 15% after challenge, the median PEF change after bronchoconstriction was lower than the corresponding FEV1 change [17% (0-52) vs. 27% (17-66)]. When different cutoff limits of PEF percent change were considered, the sensitivity of PEF to detect a significant change in FEV1 (15 or 20% change) during bronchoconstriction was low; specificity was in general higher than sensitivity. We conclude that PEF and FEV1 changes are poorly related during mild bronchoconstriction induced by different stimuli. The low sensitivity of PEF to detect mild changes in airway caliber may represent a limit in the use of PEF in the day-to-day monitoring of asthma.

Relationship between serum heat-stable neutrophil chemotactic activity during early airway reaction to allergen and the pattern of airway response (early versus late reactions) in asthmatic subjects

In order to evaluate the relationship between allergen-induced heat-stable neutrophil chemotactic activity (HS-NCA) release during early asthmatic reaction (EAR) and the presence of a late asthmatic reaction (LAR), serum HS-NCA was measured at three serum dilutions (1:5, 1:40, 1:200) during EAR induced by allergen in 26 atopic asthmatics, 13 with isolated EAR and 13 with EAR followed by LAR. HS-NCA was measured using a 48-well microchamber with 5-micron-pore-size nitrocellulose filters, using isolated neutrophils from healthy donors and the leading front technique. Subjects with LAR developed EAR after inhalation of a lower dose of allergen than subjects with isolated EAR. Increase in serum HS-NCA during EAR was significantly higher in subjects with isolated EAR than in subjects with EAR plus LAR at the 1:5 dilution, while it was significantly higher in subjects with EAR plus LAR than in the subjects with isolated EAR at the 1:200 dilution; the 1:40 dilution gave similar results in both groups. Changes in serum HS-NCA during EAR significantly correlated with the maximum decrease in forced expiratory volume in 1 s (FEV1) during LAR: a higher decrease in FEV1 during LAR was associated with a lower increase in HS-NCA at the 1:5 dilution (Spearman's rho = 0.43, rho = 0.03), and with a higher increase in NCA at the 1:200 dilution (Spearman's p = -0.46, p = 0.02). These results can be explained by the 'high-dose-inhibition' phenomenon. Assuming that HS-NCA is associated with mast cell degranulation in the airways after allergen challenge, these findings demonstrate that higher mast cell activation during EAR is present in subjects with a subsequent LAR than in subjects with isolated EAR.

Blood markers of early and late airway responses to allergen in asthmatic subjects. Relationship with functional findings

We evaluated the relationship between blood markers of mast-cell (plasma histamine and serum level of heat-stable neutrophil chemotactic activity [NCA]) and eosinophil (serum eosinophil cationic protein [ECP]) activation during early airway response (EAR) and late airway response (LAR) to allergen inhalation in 24 asthmatic subjects. After EAR, 14 subjects showed significant LAR (FEV1 fall: > or = 25%), while 10 subjects showed equivocal LAR (FEV1 fall: 15-20%). A significant increase from baseline value was observed in plasma histamine and in serum NCA during both EAR and LAR, while serum ECP significantly increased only during LAR. The sensitivity of different markers to detect significant FEV1 fall during EAR and LAR was low, except for NCA. Changes in blood mediators were similar in both groups with significant and equivocal LAR. There was a significant relationship between the increase in NCA during EAR and the severity of LAR. Stepwise regression between changes in different blood markers showed a significant relationship between histamine increase during EAR and ECP increase during LAR. Thus, serum NCA is a more sensitive marker of EAR and LAR than plasma histamine and serum ECP, and its increase during EAR seems predictive of the severity of the subsequent LAR.

Tolerance to the protective effect of salmeterol on allergen challenge

Long-term treatment with inhaled beta 2-agonists may be associated with a deterioration in asthma control, potentially due to tolerance. Regular use of short-acting beta 2-agonists has been shown to induce tolerance to allergen or adenosine 5'-monophosphate challenge. The aim of the study was to detect the efficacy of a single dose and a short-term treatment with salmeterol, a long-acting beta 2-agonist, to protect against early asthmatic reaction (EAR) to allergen. Eight subjects with mild allergic asthma underwent two treatment periods in which subjects performed an allergen challenge (specific bronchial provocation test) protected by a single dose (50 micrograms) of salmeterol (Salm-1) followed by a second specific bronchial provocation test after regular treatment with salmeterol for 1 week (Salm-2), or a single dose of placebo (Plac-1) and regular treatment (1 week) with placebo (Plac-2). Each subject performed both treatments in a randomized order. Each time allergen challenge was performed 1 h after last drug inhalation and it was stopped when the same provocative dose of allergen of a previous screening allergen challenge was achieved. The maximum decrease in FEV1 and area under curve in the first hour after allergen inhalation were significantly lower in Salm-1 (max delta FEV1 %, median [range]: 4%[0 to 9]) with respect to Salm-2, Plac-1, Plac-2 (24%[13 to 38], 31%[19 to 50], 30%[6 to 44], respectively, p < 0.001); there was no difference among Salm-2, Plac-1 and Plac-2. In Salm-1, all subjects were protected against EAR, whereas in Salm-2 only 2 subjects showed a partial protection. In conclusion the protective effect of a single dose of salmeterol against allergen-induced EAR was lost after regular treatment with salmeterol for 1 week. The clinical relevance of this mechanism remains to be elucidated.

Comparison between hypertonic and isotonic saline-induced sputum in the evaluation of airway inflammation in subjects with moderate asthma

BACKGROUND

Hypertonic saline-induced sputum has recently been used for the evaluation of airway inflammation in asthma.

OBJECTIVE

To assess the effect of hypertonicity on airway inflammation.

METHODS

We compared the inflammatory cell composition of hypertonic saline-induced sputum with that of isotonic saline-induced sputum in 21 asthmatic subjects and, at baseline and 30 min after each sputum induction, we measured bronchial hyper-responsiveness to methacholine as an indirect marker to detect increased airway inflammation. On two different days, the patients inhaled hypertonic saline (3-5% NaCl) or isotonic saline (0.9% NaCl) for 30 min via an ultrasonic nebulizer, while monitoring FEV1. Sputum was collected for inflammatory cell analysis.

RESULTS

There was no difference in inflammatory cell percentages obtained with the two methods. Eosinophils were > 1% in 20 subjects after hypertonic saline and in 16 subjects after isotonic saline, but this difference was not statistically significant. Intraclass correlation coefficients for sputum inflammatory cells obtained with the two methods were +0.642 for eosinophils, +0.644 for neutrophils, +0.544 for lymphocytes and +0.505 for macrophages. Hypertonic saline induced bronchoconstruction in a significantly greater number of subjects than isotonic saline. Also, hypertonic saline increased bronchial responsiveness to methacholine, while isotonic saline did not.

CONCLUSION

We conclude that hypertonicity does not affect sputum cell composition, suggesting that inflammatory cells in hypertonic saline-induced sputum are probably preexisting and not acutely recruited in the airways by the hypertonic stimulus. However, the bronchoconstriction and the increase in bronchial hyper-responsiveness after hypertonic saline inhalation may imply the release of inflammatory mediators. This fact must be considered in the evaluation of soluble markers of inflammation in hypertonic saline-induced sputum.

Effect of short-term NO2 exposure on induced sputum in normal, asthmatic and COPD subjects

The aim of this study was to assess the effects of short-term exposure to low levels of nitrogen dioxide (NO2) on airway inflammation. We studied seven normal, eight mild asthmatic and seven chronic obstructive pulmonary disease (COPD) subjects. All subjects were exposed to air or to 0.3 parts per million (ppm) NO2 for 1 h, with moderate intermittent exercise, on different days and in random order. Before and 2 h after exposure, symptom score and results of pulmonary function tests (PFTs) were assessed. All subjects performed nasal lavage and hypertonic saline (HS) inhalation to collect sputum 2 h after both exposures. Asthmatic subjects had a higher percentage of eosinophils than normal and COPD subjects in HS-induced sputum after air (asthmatics: median 13 (range 0.4-37)%; normals: 0 (range 0-2)%; COPD 1.8 (range 0.1-19)%), whilst COPD patients showed a higher percentage of neutrophils than the two others groups. No significant differences in PFT values or percentages of inflammatory cells were observed in nasal lavage and in HS-induced sputum in normal, asthmatic and COPD subjects after NO2 exposure compared to air exposure, except for a mild decrease in forced expiratory volume in one second (FEV1) 2 h after NO2 exposure in COPD patients. Symptom score showed a mild increase after NO2 exposure both in normal subjects and in COPD patients. We conclude that short-term exposure to 0.3 ppm nitrogen dioxide does not induce an early detectable acute inflammation in proximal airways of normal subjects or of patients with asthma or chronic obstructive pulmonary disease.

Recalcitrant organochlorine compounds in captive bottlenose dolphins (Tursiops truncatus): biomagnification or bioaccumulation?

Organochlorine residues were measured in the diet, blood, faeces and exhaled air of captive bottlenose dolphins (Tursiops truncatus) to evaluate the absorption efficiency from food and the eliminatory potential via faeces and exhaled air. Differences between air-breathing and water-breathing animals feeding on similar prey are briefly discussed. It is concluded that high concentrations of recalcitrant organochlorines currently found in marine mammals feeding on fish are essentially due to the lack of branchial elimination and not to their predator status.

Oral slow-release theophylline does not prevent early and late asthmatic response to allergen in sensitized subjects

In order to assess whether treatment with oral slow-release theophylline prevents early (EAR) and/or late (LAR) airway responses to allergen, we treated six asthmatic subjects with either placebo or oral theophylline (350 mg b.i.d.) for one week before specific bronchial provocation test (sBPT) with allergen, in a double-blind, cross-over, placebo-controlled study. All subjects had previously shown both EAR and LAR to allergen sBPT. On the day of sBPT, serum theophylline concentration was > 9 micrograms.ml-1 in all subjects treated with theophylline except one (mean 9.8 +/- 2.6 micrograms.ml-1). The total dose (TD) of inhaled allergen, and the provocative dose of allergen causing a 15% fall in forced expiratory volume in one second (PD15FEV1) during sBPT was mildly but significantly lower during theophylline-sBPT than during placebo-sBPT. Theophylline treatment reduced EAR (maximum FEV1 fall from baseline: 26.3 +/- 6.7 vs 32.2 +/- 9.5% after placebo treatment) but not LAR (19.5 +/- 6.5 vs 26.3 +/- 6.1%). A significant protection of LAR (a reduction in FEV1 fall after theophylline treatment 50% more than after placebo treatment) was observed in only 2 out of 6 subjects. Area under the curve was not significantly different after the two treatments. There was no relationship between serum theophylline levels and the degree of protection on EAR or LAR. The decrease in PD15FEV1 methacholine observed at the end of LAR was similar in the two treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Peak expiratory flow monitoring in diagnosis and management of occupational asthma

The role of peak expiratory flow (PEF) monitoring in the diagnosis of occupational asthma has recently been assessed by several studies, which agree that this procedure should always be used to confirm the relationship between symptoms and occupational exposure. Some specific issues should be satisfied: a minimum number of four PEF measurements in a day; several weeks of monitoring in and out of work; and the presence of specific patterns of PEF changes. The sensitivity and specificity of PEF monitoring to detect occupational asthma, in comparison with the specific challenge test in the laboratory (the "gold standard") have been shown to be fairly high, although many authors believe that PEF monitoring cannot substitute for the specific challenge test. Limitations include: the low sensitivity of PEF to detect mild changes in airway calibre with respect to forced expiratory volume in one second (FEV1); the blunting effect of pharmacological treatment; the episodic and irregular exposure to the sensitizer in the workplace; and the compliance and honesty of the subject. Further studies are required to select the best indices of daily and day-to-day variability to be used in the evaluation of PEF changes between work and out-of-work periods.