Patterns of sensitization to inhalant and food allergens among pediatric patients from the Moscow region (Russian Federation)

The immunological profiles of human specific IgE (sIgE) and specific IgG4 (sIgG4) vary by genetic predisposition, living conditions in different geographical locations and patient’s age. The aim of our study was to analyze sIgE and sIgG4 patterns and their age-dependent changes in patients from the Moscow region. For identifying sIgE and sIgG4 profiles the blood samples from 513 patients aged 6 months to 17 years who were showing symptoms of allergic diseases were analyzed using microarrays containing 31 allergens. The highest sIgE prevalence was observed for birch pollen (32%) among pollen allergens, cat dander (24%) among indoor allergens, and egg whites (21%) among food allergens. The most common sIgG4 response was developed toward egg whites (80% of patients). Age-related elevation was identified for patients with increased sIgE to pollen allergens and indoor allergens (cat or dog dander and house dust mites). For each allergen, the proportion of cases with significant levels of sIgG4 appeared to increase with patients’ age. The data on allergen-specific sIgE and sIgG4 prevalence show both general trends and some local special aspects that are indicative for the Moscow region. This information should be useful in terms of epidemiology of allergic diseases.

Bronchodilation test in patients with allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) may be considered a risk factor for the onset of asthma. Recently, it has been reported that forced expiratory flow between 25% and 75% of vital capacity (FEF₂₅₋₇₅) may predict a positive response to bronchodilation test in asthmatic children. The aim of this study was to evaluate a large group of adult AR patients to investigate the frequency of response to bronchodilation test and FEF₂₅₋₇₅ values.

METHODS

One thousand four hundred and sixty-nine consecutive patients suffering from persistent AR were evaluated. Clinical examination, spirometry, and bronchodilation test were performed in all patients.

RESULTS

In this study, 62.9% of patients had reversibility to bronchodilation test and 17.8% had impaired FEF₂₅₋₇₅ values (≤ 65% of predicted). Impaired FEF₂₅₋₇₅ values associated with longer rhinitis duration may predict reversibility to bronchodilation test (OR = 11.3; P < 0.001). In addition, a FEF₂₅₋₇₅ cutoff value ≤ 71% of predicted may already discriminate patients with reversibility.

CONCLUSIONS

This study highlights that about two-thirds of patients with persistent AR may be considered at risk of becoming asthmatic. This finding should be adequately considered as a precocious spirometry may allow the early detection of patients prone to develop asthma and consequently to treat them.

Effect of aging on the relationship between asthma severity and bronchial hyperresponsiveness in children with asthma

An association between asthma and bronchial hyperresponsiveness (BHR) has been demonstrated. It is possible that the relationship between asthma severity and BHR in children with asthma is different in infants and in adolescents. The aim of this study is therefore to evaluate the effect of aging on the relationship between the severity of asthma and BHR in children with asthma. We measured BHR in 386 subjects ranging from 2 to 20 years of age. The subjects consisted of 323 children with asthma (boys:girls = 193:130, mean age 9.7 years) and 63 age-matched controls (boys:girls = 25:38, mean age 8.2 years). BHR was measured using the methacholine inhalation challenge by measuring the transcutaneous oxygen pressure (tcPO2) in children less than 6 years of age (Dmin-PO2) and by measuring the respiratory resistance (Rrs) in children 6 years of age and older (Dmin-Rrs). Throughout the whole age range, both the Dmin-PO2 and Dmin-Rrs in each asthma severity group were higher than those in the controls. In the asthmatics aged 2-5 years, the Dmin-PO2 levels in the mild asthma group were higher than those in the moderate and severe asthma groups (p < 0.001, p < 0.001, respectively), and the Dmin-PO2 levels in the moderate asthma group were also higher than those in the severe asthma group. This tendency was also found in the age ranges of 6-9 years and 10-13 years. In the asthmatics aged 14-20 years, the Dmin-Rrs levels were not significantly different among the three groups. Taken together, these data show that aging has an effect on the relationship between the severity of asthma and BHR during childhood and that BHR may not be the sole determinant for the severity of asthma in adolescence.

The blocking effect of essential controller medications during aspirin challenges in patients with aspirin-exacerbated respiratory disease

BACKGROUND

The blocking effect of controller medications for asthma could have an effect on the outcome of aspirin challenges in patients suspected of having aspirin-exacerbated respiratory disease (AERD).

OBJECTIVE

To evaluate whether there was any blocking effect of long-acting beta2-agonists, systemic corticosteroids, and/or inhaled corticosteroids alone or as co-therapy with leukotriene modifier drugs (LTMDs).

METHODS

Between 1981 and 2004, 678 patients with suspected AERD were admitted for aspirin challenge and desensitization. All patients had asthma, chronic sinusitis, nasal polyposis, and at least 1 historical reaction to a nonsteroidal anti-inflammatory drug. Asthma controller medications taken during aspirin challenge were recorded and analyzed with respect to their potential effects on 4 possible outcomes of aspirin challenge, namely, naso-ocular reaction, lower airway reaction, classic upper and lower airway reaction, or a negative challenge result.

RESULTS

When compared with AERD patients who received no controller medications, the combined use of LTMDs, inhaled corticosteroids, and long-acting beta2-agonists led to a statistically significant change in aspirin challenge outcomes (P = .009), mainly shifting the reaction from a classic upper and lower respiratory tract reaction to naso-ocular reactions only. LTMDs appeared to have the strongest effect (P < .001) in blocking lower respiratory tract reactions. Systemic corticosteroids did not have the same effects. Blocking of both upper and lower respiratory tract reactions to aspirin as a result of taking controller medications did not occur.

CONCLUSION

Controller medications are frequently needed to stabilize airways of patients with AERD. LTMDs alone or in combination with other controllers blocked lower respiratory tract reactions during aspirin challenge in some patients with AERD but did not change the overall rate of positive aspirin challenge results and did not lead to false-negative challenges.

Is clinical wheezing reliable as the endpoint for bronchial challenges in preschool children?

The present study was designed to compare the clinical finding of wheeze by auscultation with an objective evaluation by acoustic means at the endpoint of a bronchial challenge in preschool children. Challenges were undertaken using a tidal breathing method in 51 preschool children as part of the investigation of possible asthma. An electronic stethoscope was used for auscultation of each lung and for the simultaneous recording of the acoustic sonogram for analysis. In 24 children, the pediatrician determined that the challenge was positive, and in 22 of these, he heard wheezing at the endpoint of the challenge. In 2 children the challenge was considered positive, based on a modest fall in saturation. The acoustic record was scanned manually for presence of wheeze defined in terms of duration, and power spectrum without reference to auscultatory findings. In positive challenges, the mean wheeze rate was 28.1% (95% CI, 19.5-36.8%), while no wheeze was detected acoustically in negative challenges. Using a cutoff wheeze rate (duration of wheeze/duration of breath phase x100) of 10% for the whole group, clinical wheezing detected by the pediatrician had a sensitivity of 100% (no false negatives) and a specificity of 91%. In conclusion, the clinical observation of wheeze agrees very well with its detection by acoustic measurement at the endpoint of a bronchial challenge in preschool children.

Lung function, airway reactivity, and atopy in newly hired female cotton textile workers

To assess changes in lung function and airway reactivity resulting from exposure to cotton dust, and the role of atopic status in these changes, the authors observed a group of 225 newly hired Chinese textile workers for 1 yr. All workers were female, lifelong nonsmokers, and none of them had been exposed previously to cotton or other occupational dust. Atopic status was determined at baseline. Spirometry, response to methacholine challenge, and total serum immunoglobulin E level were examined at baseline and again after subjects began work in the cotton mills. Obvious cross-shift drops in forced expiratory volume in 1 sec (FEV1.0), and declines in forced vital capacity and FEV1.0 over 1 yr, were observed. Atopic workers had a significantly greater acute drop in FEV1.0 than did nonatopic workers. Both atopic and nonatopic workers had slightly increased airway reactivity at 1 yr, compared with baseline values. The results suggest that exposure to cotton dust is responsible for acute and longitudinal declines in lung function, as well as for slightly increased airway reactivity. Atopy may interact with cotton dust to accentuate the acute lung function response.

Use of specific inhalation challenge in the evaluation of workers at risk for occupational asthma: a survey of pulmonary, allergy, and occupational medicine residency training programs in the United States and Canada

STUDY OBJECTIVES

To document the current practice of occupational asthma (OA) diagnosis and use of specific inhalation challenge (SIC).

DESIGN, SETTING, AND PARTICIPANTS

A survey evaluating the current practice of SIC was mailed to 259 residency training programs in adult pulmonary diseases, allergy and immunology, and occupational medicine accredited in the United States and Canada during the year 2000.

RESULTS

Forty-six percent (123 of 259 programs) participated. Ninety-two programs reported that patients with OA were seen during the previous year, 15 programs reported that SIC had been performed, and 10 programs reported that patients had been referred to other sites for SIC. A total of 259 patients underwent SIC. No unexpected adverse reactions were reported. Forty-one programs reported that they had been willing to undertake SIC but were unable to do so. The most common barriers cited were lack of availability of SIC within the evaluating institution, inability to locate a site for referral, concerns about reimbursement, and lack of an appropriate diagnostic reagent for use in SIC. Seventy-four programs indicated that SIC was useful, and 34 programs included training in the use of SIC was part of the residency curriculum.

CONCLUSION

Although SIC is considered the "gold standard" for objective documentation of OA, the test is performed in only a few institutions in the United States and Canada. Many institutions indicate that SIC is not available, even when desired for patient management. Only a minority of participating residency training programs include SIC as a formal part of the training curriculum.

[Specific bronchial provocation test with solid aerosols. Quantification of results]

OBJECTIVES

To determine 1) the level of specific bronchial reactivity by challenge with flour and 2) the criteria of positivity using a new method for the expression of the results.

METHOD

Thirty-eight asthmatic subjects, occupationally exposed to wheat flour, performed a challenge with lactose then with flour. The instantaneous measurement of the concentration and of the inspiratory airflow were used to calculate the inhaled dose and to establish the dose-response relationships. The results were given 1) by the dose of flour provoking a 20% fall in FEV1 (PDf20), 2) by the comparison of the variation of the FEV1 during the challenge with flour to the distribution of the values observed during the challenge with lactose (inferior limit of the confidence interval at 99.7%).

RESULTS

The variations of the FEV1 were not significantly related to the inhaled dose of lactose. The specific bronchial reactivity to flour was a continuous data and three groups were distinguished: 1) subjects (n = 15) with high bronchial reactivity had a fall of FEV1 of more than 20% 2) subjects (n = 13) without significant variation of the FEV1 for doses higher than 1,400 micrograms by comparison to the distribution of the values of the lactose test 3) subjects (n = 10) with a significant fall of FEV1 by comparison to the distribution of the values of the lactose test but lower than 20%. For this group with moderate reactivity, the flow of the inhaled dose may be determinant for the bronchial response.

CONCLUSIONS

PDf 20 measures the specific bronchial reactivity. However, if the fall in FEV1 is lower than 20%, the specific challenge with flour may be compared to the challenge with lactose to detect the subjects with moderate reactivity. Our results confirmed the role of the inhaled dose and suggested the role of the dose rate in the outset of bronchial obstruction among asthmatic subjects.

Evidence for genetic associations between asthma, atopy, and bronchial hyperresponsiveness: a study of 8- to 18-yr-old twins

We measured asthma in the last 12 mo, diagnosed by a respiratory physician at interview; atopy, defined by a positive skin prick test to any of eight common allergens; and bronchial hyperresponsiveness (BHR) to hypertonic saline, in 381 twin pairs aged 8 to 18 yr selected from the Australian Twin Registry-183 monozygous (MZ) and 198 dizygous (DZ). The associations between twins, as measured by an odds ratio, were greater in MZ pairs compared with DZ pairs for asthma: 25.6 (95% confidence interval 11.3- 57.8) versus 1.9 (1.0-3. 5); atopy: 14.6 (7.1-30.1) versus 2.5 (1.4- 4.5); and BHR: 14.1 (6. 4-31.0) versus 4.2 (2.1-8.6) (all p < 0.002). The associations between each pair of traits within an individual were slightly greater than the association between one trait in a twin and the other trait in the cotwin (cross-trait cross-pair) in MZ pairs. Further, the associations in MZ pairs were greater than in DZ pairs (p < 0.05). Under the assumptions of the classic twin model, these data suggest that the strong cross-sectional associations between these three traits are due to an overlap between the genetic factors involved in each of these three traits.

The effects of inhaled budesonide on circulating eosinophil progenitors and their expression of cytokines after allergen challenge in subjects with atopic asthma

Allergen inhalation by dual responder subjects with atopic asthma is associated with an increase in circulating eosinophil/basophil colony-forming units (Eo/B CFU) and granulocyte-macrophage colony- stimulating factor (GM-CSF) immunolocalization in Eo/B colony cells grown in vitro. The current study examined the effect of the inhaled corticosteroid, budesonide, on the number of allergen- induced circulating eosinophils and Eo/B CFU, and immunolocalization of GM-CSF and interleukin-5 (IL-5) in Eo/B colony cells grown in vitro. Sixteen subjects with mild atopic asthma were treated for either 7 or 8 d with 200 microg inhaled budesonide or placebo twice a day. Peripheral blood was collected before and 24 h after allergen inhalation challenge and nonadherent mononuclear cells (NAMC) were grown in methylcellulose culture. Eo/B CFU were enumerated after 14 d in culture, and prepared on slides for immunocytochemistry. Budesonide attenuated the allergen-induced increase in circulating eosinophils (4.0 +/- 0.4 x 10(5)/ml versus 6.5 +/- 0.7 x 10(5)/ml, p = 0.0001), circulating Eo/B CFU (12.4 +/- 2.3/10(6) NAMC versus 18.8 +/- 4.6/10(6) NAMC, p = 0.05), and immunolocalization of GM-CSF in Eo/B colony cells (11.8 +/- 1.9% positive versus 18.0 +/- 2.2%, p = 0.01) but not immunolocalization of IL-5 (7.9 +/- 1.4% versus 4.5 +/- 0.6%, p > 0.05). Inhaled budesonide attenuated the number of allergen-induced circulating eosinophils and their progenitors grown in the presence of GM-CSF, which may partially be a result of regulating eosinophil progenitor expression of the autocrine growth factor GM-CSF.

Predictors of late asthmatic response. Logistic regression and classification tree analyses

To identify predictors of the late asthmatic response (LAR), we reviewed data from 60 asthmatic subjects who had undergone allergen challenge over the past 5 yr (33 females, age 31.4 +/- 6.7 yr [mean +/- SD], FEV(1) 90% +/- 14% predicted). Variables considered likely predictors of LAR included baseline FEV(1), PC(20) methacholine (PC(20)), sputum eosinophil percent, and the decrease in FEV(1) within 20 min of allergen challenge. A LAR (FEV(1) >/= 15% fall between 3 and 7 h after challenge) was documented in 57% of subjects. A variety of logistic regression methods revealed a significant inverse association between LAR and PC(20) (odds ratio [OR] = 0.14 [95% CI = 0.03-0.66]) and a positive association between LAR and the decrease in FEV(1) at 20 min (OR = 1.18 [1.04 -1.33]). Classification tree analysis revealed that a threshold of 0.25 mg/ml for PC(20) was most predictive of LAR; LAR developed in 87% of those with PC(20) </= 0.25 mg/ml (n = 23) and in 38% of those with PC(20) > 0.25 mg/ml (n = 37). Notably, in subjects with PC(20) > 0.25 mg/ml, the incidence of LAR increased from 38% to 57% if the allergen-induced decline in FEV(1) at 20 min was >/= 27%. Surprisingly, baseline FEV(1) and percent eosinophils in induced sputum were not significantly associated with LAR. We conclude that a threshold value of 0.25 mg/ml for PC(20) methacholine is a good predictor of LAR. Measuring the PC(20) methacholine may be useful as a screening method to improve the efficiency of identifying asthmatic subjects with a LAR.

[Asthma in hairdressers: a report of 5 cases]

The paper reports 5 cases of bronchial asthma in hairdressers exposed to bleaching dusts containing potassium and ammonium persulphate. All subjects complained of asthmatic symptoms at diagnosis, and underwent measurement of non-specific bronchial hyperresponsiveness to methacholine, skin prick tests for common allergens, PEF monitoring during 2 weeks at work, specific bronchial challenge (SBC) test with bleaching dust, and assessment of airway inflammation by induced sputum technique. All subjects were reassessed during a follow-up of 1 to 5 years. All subjects were negative for skin prick tests, but 3 showed an abnormal PEF variability at work (Maximal Amplitude > 10%, in at least half of the monitoring period). All subjects showed a positive airway response to SBC with bleaching dust, and 4 subjects did not react to the control tests with lactose dust. One subject only showed a high percentage of eosinophils (> 3%) in the induced sputum, while all were hyperreactive to methacholine (PD20FEV1 < 0.3 mg). During the follow-up, 2 subjects stopped working and 4 were treated by inhaled corticosteroids and bronchodilators. All subjects reported a significant improvement in asthmatic symptoms, related partly to the reduction of occupational exposure in the workplace and to the efficacy of anti-inflammatory treatment. In conclusion, similar findings were observed in these 5 cases of hairdresser asthma: absence of atopy, positive response to SBC, mild changes in PEF and variable percentages of eosinophils in induced sputum. Pharmacological treatment, associated with reduction of occupational exposure, could improve asthmatic symptoms, despite continuing the job.

Baker's asthma: still among the most frequent occupational respiratory disorders

BACKGROUND

Baker's asthma and rhinitis are among the most frequent occupational respiratory disorders.

OBJECTIVE

The aim of the study was to evaluate the frequency of work-related symptoms and the clinical relevance of sensitization to allergens in screened and symptomatic bakers.

METHODS

Eighty-nine bakers participating in a screening study and 104 bakers filing a claim for compensation were examined with regard to occupational and clinical case history, lung function parameters, and sensitization to bakery allergens by skin prick tests, specific IgE analyses, and inhalative challenge tests.

RESULTS

A high prevalence of respiratory disorders, abnormal lung function parameters, and sensitization to bakery allergens exists. Most frequently, bakers with workplace-related respiratory symptoms showed sensitization to wheat flour (64%), rye flour (52%), soy bean flour (25%), and alpha-amylase (21%). The correlation between these sensitizations and asthma case history and inhalative challenge test responses was significant. However, approximately 29% of the bakers with respiratory symptoms showed no sensitization to these bakery allergens, whereas 32% of the sensitized bakers in the screening group had no workplace-related symptoms. Atopic status defined by skin prick test sensitization to common allergens or elevated total IgE levels was found to be a risk factor for the development of sensitization to bakery allergens and respiratory symptoms. On the other hand, there is evidence for an increased frequency of elevated total IgE as the result of occupational allergen exposure because respective findings were observed in bakers without symptoms.

CONCLUSION

Sensitization to bakery allergens seems to be the main cause of baker's asthma and rhinitis but cannot explain the asthma case history in each case. Further methods are required to objectively assume irritative pathomechanisms. Our findings indicate the necessity for an improved primary prevention of exposure to inhalative noxae in bakeries.

Variation in bronchial responsiveness in the European Community Respiratory Health Survey (ECRHS)

Attempts to compare bronchial responsiveness between populations have been hampered by between-study differences in the pharmacological agent of provocation, the method of administration and the summary statistic employed. The European Community Respiratory Health Survey used methacholine challenge delivered by Mefar dosimeter according to a standardized protocol used in 35 centres in 16 countries. Data were obtained from 13,161 men and women, aged 20-44 yrs at the start of the study. The dose of methacholine producing a 20% fall in forced expiratory volume in one second (FEV1) (PD20) and the regression coefficient of percentage decline in FEV1 with log dose, were calculated ("slope", after transformation), with and without calibration of nebulizers by weight and adjustment for nonresponse bias. Standardization for baseline lung function and variation in smoking prevalence was applied to slope. Results were robust to whichever summary measure was used, and to the various adjustments. Responsiveness was low in Iceland and Switzerland, and in most centres in Sweden, Italy and Spain, and high in New Zealand, Australia, the USA, Britain, France, Denmark and Germany. Bronchial responsiveness varies considerably in Europe, and high levels are not confined to the English-speaking world.

Annual variability in methacholine responsiveness in nonasthmatic working adults

Change in airway responsiveness is used frequently as a clinical as well as an epidemiological tool. Changes in airway responsiveness can be superior to other measures of lung function in that they are more sensitive indicators of an environmental effect. However, normal variation in test results must be defined before change can be interpreted. To characterize annual variability in airways responsiveness, we administered a high-dose methacholine challenge at 1 yr intervals for up to 4 yrs to 105 healthy, nonasthmatic working subjects. Using this high-dose protocol, the majority of tests (83%) produced at least a 20 % fall in forced expiratory volume in one second (FEV1), allowing standard calculation of the provocative dose of methacholine causing a 20% fall in FEV1 (PD20). An annual change in methacholine responsiveness by one or more doubling doses was seen in at least 30% of subjects each year. The components of variance of airways responsiveness measures were estimated to allow direct comparison of within-subject and between-subject variability. The within-subject variability in PD20, was markedly greater than the comparable within-subject variability in FEV1. Level of FEV1 and age were both significant determinants of methacholine responsiveness. Comparison of two methods of expressing methacholine responsiveness (PD20 using the full challenge up to 250 mg x mL(-1) methacholine, and the dose-response slope using data up to 32 mg x mL(-1) methacholine as the maximum dose) had similar annual variability in censored data and mixed-effects models. We then developed an approach to statistical analysis of "right-censored" methacholine challenge data using a maximum likelihood estimation under a censored Gaussian model. These studies of methacholine responsiveness provide normative data on annual test variability in healthy, nonasthmatic working adults, and show that a shorter low-dose challenge has comparable annual variability to a lengthier high-dose challenge.

Inhalation challenges with agents causing occupational asthma

Occupational asthma (OA) is steadily emerging as the principal cause of respiratory disease due to the workplace environment. One of the key means to ascertain diagnosis of OA is specific inhalation challenge (SIC) with occupational agents. This review: 1) describes the methodology of SIC, with a special emphasis on procedures aimed at increasing the safety and validity of these tests; and 2) outlines the roles of SIC in the diagnosis of OA in clinical and medicolegal assessment, epidemiological studies, surveillance programmes and the investigation of the pathophysiological mechanisms of asthma and OA. We discuss areas of future development, including the development of apparatus which allows exposure of subjects to low and stable concentrations of the occupational agent and the assessment of preventive procedures.

[The specific bronchial provocation test in the diagnosis of occupational asthma]

Specific bronchial challenge (SBC) testing is a key technique for diagnosing the origin of occupational asthma (OA). SBC is indicated in specific circumstances, including whenever several agents present in the work environment may be the cause of OA, when new or unusual occupational agents need to be identified, when evidence for legal action is required, or when research is conducted. SBC procedures are not standardized, because of the great diversity of occupational agents and the variety of physical and chemical properties involved. Thus, SBC testing with agents found in fumes, gases or vapors can be administered in special cabins or in closed circuits with continuous monitoring of sub-irritant concentrations. Agents found in dust, most but not all of which have high molecular weights, may be appropriate for routine SBC testing in an allergy laboratory. This paper will treat only these cases. SBC must be formed in specialized centers by experienced personnel, as it is a sophisticated and potentially dangerous technique. We describe a series of 20 patients diagnosed of OA in our unit over the past two years in whom SBC provided an etiologic diagnosis. All were exposed to dust or aerosols at work. The cause was a substance of high molecular weight in 17 cases, and low molecular weight in 3. The procedure used is described and models of bronchial response are discussed.

Interpretation of positive results of a methacholine inhalation challenge and 1 week of inhaled bronchodilator use in diagnosing and treating cough-variant asthma

BACKGROUND

In diagnosing cough due to asthma, methacholine chloride inhalation challenge (MIC) interpreted in a traditional fashion has been shown to have positive predictive values from 60% to 82%.

OBJECTIVE

To determine whether any features of positive results of an MIC or the results of a 1-week trial of inhaled beta-agonist therapy were helpful in predicting when the cough was due to asthma.

METHODS

The study design was a prospective, randomized, double-blind, placebo-controlled, crossover format performed in adult, nonsmoking subjects, who were referred for diagnosis and treatment of chronic cough. The subjects had no other respiratory complaints or medical conditions for which they were taking medications, the results of baseline spirometry and chest roentgenograms were normal, and the results of MIC were positive. After obtaining baseline data, including MICs on 2 separate days, objective cough counting, and self-assessment of cough severity using a visual analog scale, subjects were randomized to receive 2 inhalations (1.3 mg) of metaproterenol sulfate or placebo by metered dose inhaler attached to a spacer device every 4 hours while awake. At 1 week, data identical to baseline were collected, and subjects received the other metered dose inhaler for 7 days. At 1 week, data identical to baseline were collected. After completion of the protocol, subjects were followed up in the clinic to observe the final response of the cough to specific therapy.

RESULTS

Based on the disappearance of the cough with specific therapy, the cough was due to asthma in 9 of 15 subjects and nonasthma in 6 of 15 subjects. Baseline data were similar between groups. With respect to MICs, there were no significant differences between groups in the cumulative dose of methacholine that provoked a 20% decrease in forced expiratory volume in 1 second from the postsaline baseline value (PD20 values), slopes of dose-response curves, and maximal-response plateaus. Cough severity significantly improved after 1 week of metaproterenol use compared with the severity of the cough at baseline (P = .03) and with placebo (P = .02) only in subjects with asthma.

CONCLUSIONS

No matter how the results are analyzed, positive MIC results, without observing response to therapy, are only consistent with asthma as the cause of the cough. The results are only diagnostic of asthma when they are followed by a favorable response to asthma therapy. After 1 week of inhaled beta-agonist, only the cough due to cough-variant asthma is significantly better.

Transforming growth factor-beta 1 in asthma. Measurement in bronchoalveolar lavage fluid

Airway wall remodeling is an established pathological feature in asthma. Its causes are not well understood, but one mediator of potential relevance is transforming growth factor-beta 1 (TGF-beta 1). We have measured levels of immunoreactive TGF-beta 1 in bronchoalveolar lavage (BAL) fluid from clinically stable atopic asthmatics and healthy control subjects. We have also examined the influence of allergen exposure on TGF-beta 1 release in the airways using a segmental bronchoprovocation model, with BAL performed at two time points following endobronchial allergen and sham saline challenges. Basal concentrations of TGF-beta 1 were significantly higher in asthmatics than control subjects (median 8.0 versus 5.5 pg/ml, p = 0.027). Following segmental bronchoprovocation, concentrations of TGF-beta 1 at the allergen- and saline-challenged sites were not significantly different after 10 min, (31.3 versus 25.0 pg/ml, p = 0.78), but after 24 h there were significantly higher TGF-beta 1 concentrations at the allergen-challenged sites (46.0 versus 21.5 pg/ml, p = 0.017). We conclude that basal TGF-beta 1 levels in the airways are elevated in atopic asthma and that these levels increase further in response to allergen exposure. These findings are consistent with the hypothesis that TGF-beta 1 is implicated in airway wall remodeling in asthma.

Asymptomatic airway hyperresponsiveness: a three-year follow-up

The physiopathology and significance of asymptomatic airway hyperresponsiveness (AHR) are still to be defined. Over a 3-yr period, we compared clinical, immunologic, and physiologic features of 30 subjects who had asymptomatic AHR with those of 30 symptomatic asthmatic subjects and 30 normoresponder subjects (age: 31.9 +/- 1.4 yr [mean +/- SEM]; n = 90). Each subject completed a respiratory questionnaire and underwent spirometry, measurement of bronchodilator response and peak expiratory flows, an allergy skin-prick test, blood eosinophil count, assay for total serum IgE level, and methacholine challenge. These tests were repeated annually, at the same period of the year, for 3 yr. Subjects with asymptomatic AHR had greater bronchodilator responses (p = 0.001), variability of peak expiratory flow rate (PEFR) (p = 0.02), and prevalence of atopy (p = 0.02) than did the normoreactive subjects. Compared with asthmatic subjects, subjects with asymptomatic AHR had a lower blood eosinophil count (p = 0.004), higher mean FEV1 (p = 0.006), and weaker bronchodilator response (p = 0.02), but an even greater perception of bronchoconstriction (p < 0.001). After 3 yr, the concentration of methacholine provoking a 20% decrease in FEV1 (PC20) had decreased significantly in the asymptomatic AHR subjects (p < 0.0001) as compared with the other two groups, and of the 28 subjects studied at this time, four (14.3%) had developed asthma symptoms. These last four subjects were atopic and exposed to animals when they developed asthma, had a familial history of asthma, and had an increased baseline AHR as compared with the subjects who did not develop symptoms. In conclusion, this study shows that over a 3-yr period, subjects with asymptomatic AHR had a greater increase in airway responsiveness and frequency of development of asthma symptoms than did normoresponsive subjects. Allergen exposure in sensitized subjects at the time of the study, and genetic predisposition, seemed the main risk factors for the development of symptomatic asthma in this population.

The effects of salmeterol on power output in nonasthmatic athletes

BACKGROUND

Salmeterol xinafoate is a new aerosol inhalant that is used in the treatment of asthma. It is currently banned by the International Olympic Committee because of the concern that it may lend an unfair competitive advantage to the user.

OBJECTIVE

The purpose of this study was to determine whether salmeterol improves short-term anaerobic performance in elite nonasthmatic track cyclists.

METHODS

Eleven elite track cyclists volunteered to perform a 30-second all-out cycle ergometer test 3 hours after receiving either 42 micrograms of salmeterol xinafoate or placebo applied in a double-blind crossover procedure. During the ergometer test, peak power output, total work, time to peak power, and percent fatigue (decline in power output) were measured. Pulmonary measurements were also taken before and at various time points after inhalation and the ergometer test. A methacholine challenge was administered to each subject before participation in the study to ensure that none of the subjects had any reactive airway diseases.

RESULTS

There were no significant differences (p > 0.05) between the placebo and salmeterol trials for peak power output, total work performed during the 30-second test, percent fatigue, and time to peak power. No differences between trials were observed for the pulmonary function test variables at any of the time points. Blood lactate concentrations before and after administration of drug or placebo were also not significantly different between trials. Additionally, salmeterol did not affect the maximal heart rate achieved during the test as compared with the placebo.

CONCLUSIONS

Short-term salmeterol use within the prescribed dosage was not shown to increase short-term power output in nonasthmatic cyclists.

Challenge studies of a leukotriene receptor antagonist

The leukotriene receptor antagonist pranlukast (SB 205312, ONO-1078) has demonstrated clinical activity as an antiasthma drug in traditional challenge models, including exercise-induced asthma and inhaled bronchoprovocations with sulpyrine (an aspirin analogue), antigen, methacholine, leukotriene C4, and leukotriene D4. This article reviews the results of a published sulpyrine-challenge study and two unpublished house dust mite antigen challenge studies. Statistically significant attenuation of the decrease in FEV1 induced by bronchoprovocation was observed with pranlukast compared with placebo or baseline control in all challenge studies. These challenge studies demonstrate that pranlukast significantly protects against aspirin-induced bronchoconstriction and significantly attenuates both the immediate (early) and late airway responses to inhaled allergen.

Airway responsiveness in asthma: bronchial challenge with histamine and 4.5% sodium chloride before and after budesonide

Inhalation of histamine is commonly used to assess the severity of and to monitor treatment of asthma. Histamine causes airways to narrow by acting directly on specific receptors. Hyperosmolar saline causes airways of asthmatics to narrow indirectly by endogenously mediated events that are potentially modified by drugs used to treat asthma. We wished to determine if hyperosmolar saline (S) is a useful challenge for assessing the airway responsiveness of asthmatic subjects being treated with steroids and to compare changes in airway responses to those changes observed with histamine (H). The airway responses to S and H were assessed by the dose of aerosol provoking a 20% fall in FEV1 and the percent fall in FEV1 per unit dose of aerosol inhaled-the dose response slope (DRS). We studied asthmatic subjects before and during treatment with budesonide-1000 micrograms per day. There was a significant correlation (Spearman's) between PD20 to H and S and DRS to H and S after budesonide (P < 0.05). After 2 months of treatment; the mean PD20 (95% CI) was increased 4.6 (2.5, 8.6) fold to H, and 9.7 (4.2, 22) fold to S, (P = NS) the DRS reduced 7.0 (4.3, 11.5) fold to H and 16.6 (8.4, 33) fold to S (P = NS). Responsiveness to H, measured by PD20 remained throughout the treatment, whereas five subjects did not record a 20% fall after S and the DRS decreased to values close to those we measured in healthy subjects. In conclusion, challenge with 4.5% sodium chloride can be used to assess the early benefits of treatment with aerosol steroids.

Methacholine dose-response slopes from maximal bronchial challenge tests in asthmatic children: methodological aspects

To determine whether the slope of a maximal bronchial challenge test (in which FEV1 falls by over 50%) could be extrapolated from a standard bronchial challenge test (in which FEV1 falls up to 20%), 14 asthmatic children performed a single maximal bronchial challenge test with methacholine (dose range: 0.097-30.08 mumol) by the dosimeter method. Maximal dose-response curves were included according to the following criteria: (1) at least one more dose beyond a delta FEV1 > or = 20%; and (2) a MFEV1 > or = 50%. PD20 FEV1 was calculated, and the slopes of the early part of the dose-response curve (standard dose-response slopes) and of the entire curve (maximal dose-response slopes) were calculated by two methods: the two-point slope (DRR) and the least squares method (LSS) in % delta FEV1 x mumol-1. Maximal dose-response slopes were compared with the corresponding standard dose-response slopes by a paired Student's t test after logarithmic transformation of the data; the goodness of fit of the LSS was also determined. Maximal dose-response slopes were significantly different (p < 0.0001) from those calculated on the early part of the curve: DRR20% (91.2 +/- 2.7 delta FEV1%. mumol-1) was 2.88 times higher than DRR50% (31.6 +/- 3.4 delta FEV1%. mumol-1), and the LSS20% (89.1 +/- 2.8% delta FEV1. mumol-1) was 3.10 times higher than LSS50% (28.8 +/- 1.5% delta FEV1. mumol-1). The goodness of fit of LSS50% was significant in all cases, whereas LSS20% failed to be significant in one. These results suggest that maximal dose-response slopes cannot be predicted from the data of standard bronchial challenge tests.

[The state of the atmosphere and bronchial hypersensitivity]

A bronchial provocative test employing acetylcholine revealed an excess in the numbers of the hypersensitive persons living under ecologic health hazard conditions, of 3,5-fold, which fact permits recommending it to be used in population studies to identify and administer prophylaxis of obstructive lung diseases in a timely fashion. Hypersensitivity of the bronchi in those people living under ecologic health hazard conditions is accompanied by an activation of peroxidation processes as well as changes in the parameters associated with the immune response.

[The effect of interference currents on bronchial patency and bronchial hyperreactivity in children with bronchial asthma]

The results are available on introduction of interference therapy in 30 children with bronchial asthma versus control group of 20 untreated patients. Bronchoprovocative histamine and exercise tolerance tests have specified characteristic features of interference current effects on bronchial permeability and hyperreactivity.

Single, high-dose intramuscular triamcinolone acetonide versus weekly oral methotrexate in life-threatening asthma: a double-blind study

Effective and less toxic treatments are needed for patients with severe, steroid-dependent asthma. Both low-dose oral methotrexate and high-dose intramuscular triamcinolone have been recommended for these patients. We compared the effects of these two medications on pulmonary function, peak flow rates, airway reactivity, oral steroid use, emergency room (ER) visits, and hospitalizations in patients with steroid-dependent, life-threatening asthma. In a randomized, placebo-controlled, double-blind study, we investigated 19 such patients. Six of the patients (Group I) received a single dose of 360 mg triamcinolone intramuscularly with placebo methotrexate; seven patients (Group II) received placebo triamcinolone followed by low-dose oral methotrexate (a first dose of 7.5 mg followed by 15 mg weekly); and six patients (Group III) received placebo triamcinolone with placebo methotrexate. All patients used the same high-dose inhaled steroids. The patients took tapering courses of oral steroids when needed, but attempted to reduce their oral steroid use whenever possible. Methacholine challenge testing was performed every 6 wk, pulmonary function tests every 4 wk, and home peak-flow measurements twice daily. Oral steroid use, ER visits, and hospitalizations were also monitored. The patients in the triamcinolone treatment group showed a significant and sustained increase in home peak-flow rates, and their FEV1 persistently improved by a mean of 40% (p < 0.05), whereas the FEV1 of the patients in the methotrexate treatment and placebo groups remained near baseline. The PC20 in the triamcinolone group increased progressively (p > 0.05), and the improvements in total mean reactivity were greater in this group than in either of the other two groups (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Role of airway eosinophils in the development of allergen-induced airway hyperresponsiveness in dogs

The role of the eosinophil in the development of allergen-induced airway hyperresponsiveness is uncertain. We examined whether the development of airway hyperresponsiveness in 17 dogs after inhalation of Ascaris suum allergen (10(-6) to 10(-2) weight/volume [w/v]) was associated with increases in the number and level of activation of eosinophils before and after allergen inhalation. Airway responsiveness to inhaled acetylcholine was measured before and 24 h after Ascaris inhalation. Eosinophil number was assessed by bronchoalveolar lavage performed 1 wk before allergen inhalation and 15 min after the 24 h acetylcholine challenge. Dogs that developed Ascaris-induced airway hyperresponsiveness (n = 8) had a significantly greater number of bronchoalveolar lavage eosinophils before allergen inhalation (mean +/- SEM: 4.6 +/- 1.94 x 10(4) cells/ml) than dogs that did not become hyperresponsive (n = 9) (1.2 +/- 0.81 x 10(4) cells/ml) (p = 0.03). Ascaris-induced airway hyperresponsiveness, measured 24 h after allergen inhalation, was not associated with increases in eosinophil number after allergen challenge. These results suggest that the presence of airway eosinophils before allergen inhalation is necessary for the development of allergen-induced airway hyperresponsiveness.

Rhinovirus inhalation causes long-lasting excessive airway narrowing in response to methacholine in asthmatic subjects in vivo

Exacerbations of asthma are often associated with respiratory infections, and particularly those caused by rhinovirus. The causative role of rhinovirus in these acute episodes is still unclear, since it has not been determined whether or not infection with the virus promotes excessive airway narrowing in asthma. We tested the hypothesis that experimental infection with inhaled wild-type rhinovirus 16 (RV16) increases the maximal degree of airway narrowing in response to bronchoconstrictor stimuli in patients with mild to moderate asthma. Fourteen nonsmoking subjects with atopic asthma and normal FEV1 values participated in a double-blind, placebo-controlled, parallel study. A total dose of 3 x 10(4) of the 50% tissue-culture-infective dose (TCID50) of RV16 or a placebo was administered by pipette, atomizer, and nebulizer in equal doses into both nostrils on two consecutive days. Dose-response curves for inhaled methacholine were recorded 1 d before and 2, 7, and 15 d after RV16 infection or placebo. The response to methacholine was measured by the percent decrease in FEV1, and the maximal degree of airway narrowing was expressed by the average response on the plateau of the dose-response curve. In the seven subjects receiving the virus, RV16 infection was confirmed in nasal washings and/or by an increase in antibody titer, whereas these tests were negative in the placebo group. There was no significant change in baseline FEV1 during the study in either group (p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Airway obstruction in boilermakers exposed to fuel oil ash. A prospective investigation

We prospectively investigated the lower airway response in boilermakers overhauling an oil-powered boiler. We studied 26 male boilermakers with a mean age (SD) of 43.3 (8.6) yr. Pre-exposure spirometry and methacholine challenge tests were performed before beginning the boiler overhaul; postexposure tests were performed after approximately 4 wk of work on the boiler. Exposure to particulates with an aerodynamic diameter of 10 microns and smaller (PM10) and respirable vanadium dust were estimated using daily work diaries and a personal sampling device for respirable particles. Using these estimates, we calculated average and peak exposure between pre- and postexposure tests for each subject. The average PM10 concentration ranged from 1.44 to 6.69 mg/m3, with a mean (SD) of 3.22 (1.42) mg/m3; the average vanadium concentration ranged from 2.2 to 31.3, with a mean (SD) of 12.2 (9.1) micrograms/m3. The mean postexposure fall in FEV1 was 140 +/- 160 ml (p < 0.01); 24 of 26 subjects had a drop in FEV1. For each subject, the adjusted change in FEV1 (delta FEV1.adj) was calculated by dividing the change in FEV1 by the average of the pre- and postexposure FEV1 values. The delta FEV1.adj was regressed, controlling age and current smoking status, on average and peak exposure to both PM10 and vanadium. There was a dose-response relationship between average and peak PM10 exposure and delta FEV1.adj: beta = -0.91% per mg/m3, p = 0.08 and beta = -1.03% per mg/m3, p = 0.03, respectively. However, there was no relationship between delta FEV1.adj and respirable vanadium dust concentration. Furthermore, there was no postexposure change in nonspecific airway responsiveness. In summary, we found a significant fall in FEV1 and a dose-response relationship between delta FEV1.adj and average and peak PM10 exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of inhaled beta 2 agonist and inhaled corticosteroid on airway responsiveness to allergen and methacholine

Regular treatment with salbutamol increases airway responsiveness to allergen but not to methacholine and produces tolerance to the bronchoprotective effect of salbutamol. The current study addresses the effect of inhaled corticosteroid on these aspects of regular beta 2 agonist use. A group of 13 atopic asthmatic subjects free from all asthma medications and remote from allergen exposure were studied. We used a double-blind, random-order, crossover study to compare four 1-wk treatment periods with > or = 1 wk washout: placebo, salbutamol, 200 micrograms four times per day, budesonide, 400 micrograms four times per day, and the combination of salbutamol and budesonide. We measured the methacholine PC20 and the methacholine dose shift produced acutely by 200 micrograms salbutamol after 7 d and the allergen PC15 after 8 d treatment. Blinded medications were withheld for 8 to 10 h before measurements. The methacholine PC20 was not affected by regular salbutamol but increased significantly (p < 0.014) after both budesonide-containing regimens. Neither the dose shift nor its significant reduction by regularly used beta 2 agonist were influenced by the inhaled corticosteroid. The four allergen PC15 values were significantly different from each other. Compared with placebo, the allergen PC15 was 0.6 doubling doses lower after salbutamol (p = 0.021) and 1.3 doubling doses higher after budesonide (p < 0.001); the allergen PC15 was reduced by 0.53 doubling doses from this new baseline (p = 0.039) when salbutamol and budesonide were used together.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of adenosine 5'-monophosphate and methacholine for the differentiation of asthma from chronic airway diseases with the use of the auscultative method in very young children

Methacholine and adenosine 5'-monophosphate bronchial challenges were performed in 54 young children--39 with asthma and 15 with other chronic airway diseases (CADs), with the use of the auscultative method. Children with asthma were sensitive to both methacholine and adenosine; children with CAD responded only to methacholine. We conclude that bronchial challenge with adenosine can help differentiate asthma from CAD in young children.

Impaired bronchodilator response to albuterol in healthy elderly men and women

BACKGROUND

Lymphocytes of normal elderly subjects and young asthmatics display dysfunctional beta-adrenoceptors. If beta-adrenoceptor dysfunction were found in senescent airways, it might help explain the pathogenesis of late onset asthma.

METHODS

The bronchodilatory effects of albuterol after methacholine-provoked bronchoconstriction were compared in 17 healthy young (age 20 to 36 years) and 17 healthy elderly (age 60 to 76 years) volunteer subjects. Albuterol was inhaled via dosimeter (initially 7.8 micrograms, doubling every 7.5 min) with forced expiratory flow at 50% vital capacity (FEF50) measured prior to each dose. Albuterol sensitivity was expressed as the cumulative logarithm of the area under the FEF50 recovery curve (AUC); a greater AUC meant lower sensitivity. On another study day, spontaneous recovery from methacholine was assessed similarly.

RESULTS

There was no intergroup difference in spontaneous recovery. Despite lower methacholine doses provoking similar (35%) FEF50 falls in elderly subjects, albuterol AUC was greater in elderly subjects (6,552%.min.microgram) than young subjects (3,922%.min microgram; p = 0.03). Multiple regression showed that AUC and age were related (p = 0.02).

CONCLUSION

Airway beta 2-adrenoceptor responsiveness is diminished in old age, suggesting that airway beta-adrenoceptor dysfunction may be implicated in late-onset asthma.

The measurement of methacholine responsiveness in 5 year old children: three methods compared

The aim of this study was to compare the feasibility of three techniques for measuring the response to bronchial challenge in young children: a direct airway measurement, the forced oscillation technique (FOT) for determining respiratory system resistance at 6 and 8 Hz (Rrs6 and Rrs8), and two indirect methods, the change in transcutaneous oxygen tension (PtcO2) and the detection of wheeze on auscultation of the chest. Thirty children aged 5 yrs, with a history of wheeze, and six asymptomatic controls, took part in a bronchial challenge test using methacholine administered by Wright nebulizer by the tidal-breathing method. The provocative concentration which produced a 35% increase in Rrs6 (PC35Rrs6) and a 15% decreases in PtcO2 (PC15PtcO2) were determined by interpolation, and the chest was ausculated after each dose of methacholine. The FOT was found to be unreliable in this age group: in seven children, the data were technically unsatisfactory in the presence of induced bronchoconstriction, whilst in three children, changes in Rrs were inconsistent after challenge. The use of Rrs8 did not improve the detection of positive responses. PC15PtcO2 was measurable in 29 of 30 children, and in 18 of these PC35Rrs6 was also measurable. In no subject did a significant, sustained increase in Rrs occur during challenge in the absence of a significant change in PtcO2. Wheeze was audible in only 4 of 25 (16%) of the positive and in no negative challenges. With this protocol, we found the FOT to be unreliable and the auscultation method valueless and potentially dangerous, since marked falls in PtcO2 of up to 33% sometimes occurred in the absence of wheeze.(ABSTRACT TRUNCATED AT 250 WORDS)

Relations of bronchial responsiveness to allergy skin test reactivity, lung function, respiratory symptoms, and diagnoses in thirteen-year-old New Zealand children

BACKGROUND

Many factors have been found to relate univariately to bronchial responsiveness (BR), but their independent relationships are often unclear because many are interrelated.

OBJECTIVE

The purpose of this study was to present a multivariate analysis of the closeness of the association of various factors that are related univariately to BR, including allergy skin tests.

METHODS

The results of methacholine challenge were transformed into a continuous variable (BRindex), which has a nearly Gaussian distribution. With stepwise multiple regression, the closeness of the association of the independent variables with BRindex was evaluated.

RESULTS

Of the 11 skin tests applied, four showed independent relationships to BRindex (mite, cat, dog, and Aspergillus species). The sizes of these skin test reactions were correlated with BRindex, and their sum appeared to maximize the overall correlation of allergy skin tests with BRindex (r = 0.516). The lowness of the ratio of forced expiratory volume in 1 second to vital capacity and of percent predicted forced expiratory volume in 1 second added significantly to the skin tests in correlating with BRindex, (multiple r = 0.621). Adding diagnoses and symptoms increased the multiple r to 0.685.

CONCLUSIONS

The size of the reactions to the four skin tests noted above showed much closer correlations with BR than total serum IgE had shown at age 11, and the relationship was present in asthmatic and nonasthmatic subjects.

Bronchodilator and bronchoprotective effects of cilostazol in humans in vivo

Cilostazol is a selective orally active phosphodiesterase (PDE) III inhibitor. This study was conducted to evaluate whether inhibition of PDE subtype III can reduce bronchial responsiveness. We examined the effects of cilostazol on bronchial responsiveness to methacholine in eight normal subjects by a single-blinded, crossover study. Each subject received 200 mg of cilostazol or placebo in random order. The subjects underwent methacholine challenge test 3 h after administration of each drug on two occasions separated by 5 d or more. The geometric mean value of provocative concentration of methacholine causing a 20% fall in FEV1 (PC20-FEV1) and the mean value (+/- SEM) of maximum expiratory flow on partial flow-volume curve at isovolume of 40% FVC above residual volume (PEF40) after administration of cilostazol were 25.3 (geometric standard error of the mean [GSEM], 1.35) mg/ml and 3.78 +/- 0.31 L/s, which were significantly (p < 0.02 and p < 0.05) greater than those after the placebo administration (6.81 [GSEM, 1.42] mg/ml and 2.71 +/- 0.39 L/s). All subjects complained of mild to severe headache when cilostazol was given. These findings suggest that PDE III inhibitors such as cilostazol have bronchodilator and bronchoprotective effects in humans. Further studies regarding smaller oral dosing of or aerosol administration of cilostazol or the other PDE III inhibitors are needed to determine clinical usefulness.

Extrathoracic and intrathoracic airway responsiveness in sinusitis

BACKGROUND

Asthma associated with sinusitis is supposed to be sustained by bronchoconstrictive reflexes originating in extrathoracic airway (EA) receptors.

OBJECTIVE

The study was designed to evaluate the relationship between EA responsiveness and bronchial responsiveness in sinusitis.

METHODS

We performed histamine inhalation challenge in 106 patients with chronic sinusitis, during disease exacerbation and after treatment with antimicrobials and nasal flunisolide (100 micrograms daily) for 2 weeks. Forced expiratory volume in 1 second (FEV1) and maximal mid-inspiratory flow (MIF50) were the respective indexes of bronchial and EA narrowing; the histamine concentrations causing a 20% fall in FEV1 (PC20) and 25% drop in MIF50 (PC25MIF50) were used as thresholds of bronchial and EA responsiveness. Thresholds of 8 mg/ml or less were assumed to indicate bronchial hyperresponsiveness (B-HR) or EA hyperresponsiveness (EA-HR).

RESULTS

During sinusitis exacerbation 76 patients had EA-HR, which in 46 was associated with B-HR. The values of PC20 were closely related with those of PC25MIF50 (p < 0.001). EA-HR and B-HR were strongly associated with pharyngitis. After treatment, mean PC25MIF50 and PC20 were significantly increased (p < 0.001). The improvement of PC25MIF50 was closely related to that of PC20 (p < 0.001) and to the decrease in neutrophils in nasal lavage (p < 0.05). EA-HR reversed in 58 patients and improved in 10; B-HR reversed in 29 and improved in 12.

CONCLUSIONS

Our findings suggest that in sinusitis, B-HR may be sustained by constrictive reflexes originating in pharyngeal receptors, made hypersensitive by seeding of the inflammatory process.

Hypertonic saline challenge in an epidemiologic survey of asthma in children

To evaluate sensitivity and specificity of a 4.5% hypertonic saline challenge for a diagnosis of asthma, we studied 393 schoolchildren (13 to 15 yr of age) with "current wheeze," "former wheeze," and without history of wheeze in a community-based, cross-sectional survey. These children were selected from 2.836 schoolchildren in 26 schools in greater Melbourne, Australia who completed a self-administered questionnaire on respiratory symptoms, allergic rhinitis, and eczema. Three hundred eighty-two of 393 children successfully completed a 4.5% hypertonic saline challenge with increasing inhalation periods, and 365 of 393 performed a 6-min standardized, free running exercise challenge. The prevalence of bronchial hyperresponsiveness to hypertonic saline was 20.4%. Sensitivity and specificity for the hypertonic saline challenge to identify children with "current wheeze" were 47% and 92% respectively and for the exercise challenge, 46% and 88%. The agreement of response to hypertonic saline and to exercise was only moderate (kappa = 0.43). Factors associated with increased response to hypertonic saline in a multivariate logistic regression model were a history of "current wheeze," hay fever, response to the exercise challenge, female sex, and a lower baseline predicted FEV1. These results suggest that a 4.5% hypertonic saline challenge shows sensitivity and specificity similar to a standardized exercise challenge and pharmacologic challenges and a higher sensitivity than cold air hyperventilation and distilled water to identify asthma in children in a field study. Measurement of responsiveness to hypertonic saline may be of value as an objective marker of asthma to compare prevalence studies of bronchial hyperresponsiveness and of asthma over time and between countries.

Inhibitory effect of a selective thromboxane synthetase inhibitor, OKY-046, on acetaldehyde-induced bronchoconstriction in asthmatic patients

We recently reported that inhaled acetaldehyde causes bronchoconstriction indirectly via histamine release in patients with asthma. The purpose of this study was to investigate a role of thromboxane A2 in acetaldehyde-induced bronchoconstriction in asthmatic airways. We investigated the bronchial response to inhalation of ascending doses (5, 10, 20, and 40 mg/ml) of acetaldehyde in nine asthmatic subjects who were treated with placebo or OKY-046, a selective thromboxane A2 synthetase inhibitor, of 200 mg twice a day for 3 days, and 200 mg on the fourth day (test day) in a double-blind, randomized, placebo-controlled, crossover fashion. Percentage decreases in FEV1 caused by 20 and 40 mg/ml of acetaldehyde inhalation were significantly (p < 0.05 and p < 0.01, respectively) prevented by the pretreatment with OKY-046. Geometric mean value (geometric standard error of the mean) of acetaldehyde concentration producing a 20 percent fall in FEV1 (PC20-Ac-CHO) was significantly (p < 0.01) greater with the OKY-046 pretreatment (72.2 [1.1] mg/ml) than with the placebo pretreatment (19.8 [1.2] mg/ml). We conclude that thromboxane A2 is one of contributors to acetaldehyde-induced bronchoconstriction in asthmatic subjects. It suggests that thromboxane A2 may play an important role in endogenous histamine-induced bronchoconstriction caused by acetaldehyde in asthmatic airways. We believe that this is a first report on the interaction between endogenous histamine and thromboxane A2 in asthmatic subjects.

Effect of posture on bronchial reactivity to inhaled methacholine in patients with mitral valve stenosis

To compare the effects of posture on bronchial reactivity in 12 patients with mitral valve stenosis (MS) and 10 with bronchial asthma (BA), a methacholine inhalation test was performed 2 h after being in either a supine or sitting position. All patients showed bronchial hyperreactivity to inhaled methacholine before the study. In MS patients, logarithmic values of the cumulative dose producing a 35 percent decrease in respiratory conductance (log PD35Grs) were significantly lower 2 h after being in a supine position than in those after being in a sitting position (0.71 +/- 0.78, 1.02 +/- 0.53 log units, respectively, p < 0.05). In BA patients, however, log PD35Grs did not show significant changes (0.42 +/- 0.51, 0.58 +/- 0.48 log units, respectively). Variables of pulmonary function tests showed no significant differences between the two positions in both patients with MS and BA. We conclude that the bronchial hyperreactivity in MS is enhanced after the supine position for 2 h and that the supine posture may play an important role in the pathogenesis of cardiac asthma.

Gender difference in airway hyperresponsiveness in smokers with mild COPD. The Lung Health Study

Methacholine bronchoprovocation challenge testing was successfully completed in 5,662 participants (3,556 men and 2,106 women) at the time they were randomized into the Lung Health Study, a multicenter trial designed to evaluate early intervention in chronic obstructive pulmonary disease (COPD). All participants were smokers between the ages of 35 and 60 yr who had mild COPD. The male:female prevalence of a positive challenge (PC20FEV1) was 25%:48% and 63%:87% at a PC20FEV1 of < or = 5 mg/ml (AHR5) and < or = 25 mg/ml (AHR25), respectively. This analysis explores these marked gender differences in airway hyperresponsiveness (AHR). Relative risks (RR) for predictors of AHR and the 95% confidence intervals (95% CI) were estimated using semiparametric Cox proportional-hazards models. The initial model controlled for age, gender, smoking history, height, and weight. The RR (95% CI) for female gender was 1.75 (1.60, 1.92). When the measured baseline FEV1 was added to the model as a surrogate for airway caliber, the RR for female gender decreased to 1.06 (0.96, 1.18). Thus, in this population of middle-aged smokers with mild COPD, the high prevalence of AHR appears to be associated with a decrease in airway caliber. The higher prevalence of AHR noted in women is due to their having a smaller airway caliber than their male counterparts.

Bronchial hyperresponsiveness can improve while spirometry plateaus two to three years after repeated exposure to chlorine causing respiratory symptoms

Repeated exposure to chlorine in pulp mills and paper can induce persistent asthma-like symptoms such as bronchial hyperresponsiveness and variable changes in airway caliber. The long-term time course of bronchial hyperresponsiveness has not been examined. We studied 20 of 29 subjects (69% participation rate) who demonstrated bronchial hyperresponsiveness to methacholine when they were first assessed, 18 to 24 mo after repeatedly inhaling "puffs" of high concentrations of chlorine in a paper mill over a 3-mo period. Each subject answered a respiratory questionnaire and underwent spirometry and a methacholine inhalation test 12 mo after the initial survey, 30 to 36 mo after the chlorine inhalations. Three subjects required inhaled steroids at the time of the initial survey and three at the time of the second, including two who carried on using these preparations. Only one subject changed smoking habits. There were no significant overall changes in FEV1 on the two occasions, nine subjects having a FEV1 < 80% on the first occasion and eight on the second. Six of the 18 subjects (33%) who underwent a methacholine inhalation test on both occasions had significantly improved PC20 results, including five for whom the PC20 value was within the normal range. All six subjects had normal FEV1 values on both assessments. Although changes in spirometry induced by repeated exposure to chlorine seem to persist, bronchial hyperresponsiveness can improve significantly in those with normal airway caliber. This suggests that less pronounced bronchial alterations induced by repeated exposures to chlorine may be reversible.

A set-up for bronchial provocation by continuously generated aerosols

Bronchial provocation tests have become a standard procedure to establish the diagnosis of asthma when symptoms are current but spirometry is normal. A simple, reproducible and widely used method for measuring airway responsiveness is continuous aerosol generation and tidal breathing inhalation. This paper presents the method, the apparatus built-up in our lung function office, reproducibility of aerosol production, and expression of results. With our set-up we are able to perform technically well regulated challenge. It has the advantages of relative simplicity in terms of equipment needed, short distance and no obstacles between nebulizer and mouthpiece. Our specially conceived computer programme is easy to handle, allows comparison and recalculation of data. Variations of nebulizers' output needs a carefully individual evaluation before use to allow reproducibility.

Nonspecific and specific bronchial responsiveness in occupational asthma caused by platinum salts after allergen avoidance

Most data about the course of occupational asthma after removal from exposure are based upon the longitudinal assessment of employees exposed to substances inducing late asthmatic reactions in bronchial provocation tests. It was the aim of this study to describe the course of immediate-type occupational asthma after allergen avoidance. Twenty-four platinum refinery workers were examined on two occasions. All subjects reported work-related asthma while they worked in the refinery department. The diagnosis of platinum salt asthma was established by a positive bronchial challenge test with hexachloroplatinic acid in each case. Eleven of the 24 subjects were still exposed to platinum salts at the time of the first investigation, but all had been removed from exposure for 19 mo (1 to 77) on the second investigation. Asthma was still reported by 17 subjects, and all but two showed bronchial hyperresponsiveness (PC50SGaw < 8 mg/ml) on the second investigation. Bronchial responsiveness to methacholine, skin reactivity, and bronchial responsiveness to platinum salt, as well as FEV1, did not change between assessments. Total serum IgE decreased from 126 to 103 U/ml (p < 0.005). Analysis of variance showed no association of the individual differences in PC50 (methacholine) between both investigations with smoking, time from the onset of symptoms to removal, time from removal to the first or second investigation, skin sensitization to environmental allergens, or total IgE. We conclude that both nonspecific and specific bronchial responsiveness do not decrease after removal from exposure in immediate-type asthma caused by platinum salts.

Soluble intracellular adhesion molecule 1 in bronchoalveolar lavage fluid of allergic subjects following segmental antigen challenge

This study was undertaken to determine the relationship of soluble intercellular adhesion molecule 1 (sICAM-1) levels in bronchoalveolar lavage (BAL) fluid during allergic airway inflammation to those in the vascular compartment and to cellular components in the BAL fluids. A group of 11 allergic subjects underwent initial bronchoscopy during which a control BAL was performed and normal saline (NS) and specific antigen (Ag) were administered to two sublobar segments. A second bronchoscopy was performed 17 to 21 h later, and the NS and Ag segments were lavaged. Blood was drawn before each bronchoscopic procedure. The mean concentration of sICAM-1 in BAL fluid from NS-challenged segments was 59.2 +/- 7.6 ng/ml and was not different from that in unchallenged segments (51.5 +/- 5.6 ng/ml). In BAL fluid from Ag-challenged segments, mean concentrations of sICAM-1 increased significantly to 97.5 +/- 12.5 ng/ml. Segmental antigen challenge was associated with a small but statistically significant increase in sICAM-1 concentrations in serum. The concentrations of sICAM-1 in BAL fluid after antigen challenge exceeded levels that could be accounted for by passive transudation from the circulation, based upon the magnitude of increases in BAL albumin concentrations. The levels of sICAM-1 in BAL from Ag-challenged segments were correlated significantly with the total white cell, lymphocyte, neutrophil, and eosinophil counts in BAL fluids. These results are supportive of the notion that the local release of sICAM-1 may play a role in allergen-induced inflammatory processes in the airways.