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Biomedical subjects

H Ghezzo

Publications and source records attributed to H Ghezzo.

At least 55 records · Page 3Linked to original sources
PubMed1996

Fever and leucocytosis accompanying asthmatic reactions due to occupational agents: frequency and associated factors.

Fever is sometimes associated with asthmatic reactions following specific inhalation challenges with occupational agents. Our aims were to estimate the prevalence of fever in subjects with occupational asthma confirmed by specific inhalation challenge and to examine the characteristics and clinical correlates of subjects who develop fever on specific inhalation challenge. We performed a retrospective analysis of 317 subjects who had positive specific inhalation challenge to occupational agents and a comparison of subjects who developed fever after specific inhalation challenge with a random sample of those who did not. Fifteen subjects (5%) developed fever associated with positive specific inhalation challenge. They were compared with a random sample of 60 subjects who did not develop fever. The fever group: 1) showed a larger increase in absolute number of blood neutrophils, and a larger decrease both of blood lymphocytes and forced vital capacity after specific inhalation challenge; 2) included fewer atopics; 3) had been exposed more frequently to low rather than high molecular compounds; and 4) always experienced a late reaction and had more atypical reactions. We conclude that after positive specific inhalation challenge; fever occurs infrequently, and is associated with an increase in blood neutrophils and a decrease in blood lymphocytes and forced vital capacity. Such reactions seem more likely to occur in nonatopic subjects exposed to low molecular weight agents.

Adult↗
PubMed1995

Comparison of four-times-a-day and twice-a-day dosing regimens in subjects requiring 1200 micrograms or less of budesonide to control mild to moderate asthma.

The aim of this study was to compare the efficacy, compliance and side-effects of budesonide administered twice daily (b.d.) and four times a day (q.d.) with a Turbuhaler device in asthmatic subjects requiring < or = 1200 micrograms daily. The randomized, parallel group study design included a 2-week baseline period followed by a 6-12-month treatment period. Subjects were assessed at regular intervals in hospital through FEV1, PC20 methacholine, adrenal function and throat swabs. They were asked to record their symptoms and PEF values morning and evening at home. An asthmatic flare-up, which was the main outcome resulting in a patient's termination of the study, was defined beforehand as (a) 25% or greater diurnal variability in PEF for 2 consecutive days, and/or (b) nocturnal awakenings due to asthma symptoms 2 days or more in the same week and/or (c) an increase (doubling or more) in the need for inhaled bronchodilator 2 days in the same week. Fifty-eight adult asthmatic subjects (20 males and 38 females) entered the study, one-half being randomly assigned to the b.d. regimen and one half to the q.d. regimen. Fourteen subjects were on 400 micrograms, 15 subjects on 800 micrograms and 29 subjects on 1200 micrograms of budesonide daily. Seventeen flare-ups were recorded in the b.d. regimen group as opposed to 11 in the q.d. regimen (P = 0.05), significant differences being found in the 800 and 1200 micrograms groups (a total of 13 flare-ups in the b.d. group and eight flare-ups in the q.d. group for the two doses, P = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1995

Do subjects investigated for occupational asthma through serial peak expiratory flow measurements falsify their results?

BACKGROUND AND AIM: Serial assessment of peak expiratory flow (PEF) rates has been advocated as a sensitive and specific means of investigating occupational asthma. The possibility that, for several reasons, subjects do not accurately report their values has been raised. The availability of portable instruments that assess PEF and store timings and values now make it possible to estimate compliance and accuracy of results. METHODS: Twenty-one subjects consecutively investigated for occupational asthma were asked to assess their PEF every 2 hours during the day, both at work and away from work, with a VMX instrument (Clement Clarke International, Columbus, Ohio) and record the times and values on a sheet of paper. The subjects were not aware that the data were also being stored on a computer chip. The diagnosis was occupational asthma in eight subjects, personal asthma in four subjects, and neither condition in nine subjects. RESULTS: The mean duration of recording was 36 days (range, 14 to 79 days). At least 6048 values should have been recorded, but only 4839 (80%) were either recorded or stored. Reported values corresponded precisely to stored values in 2533 of 4839 recordings (52%). The timing of the recording was also examined in relation to the time at which the recording was solicited; values recorded within 1 hour of the solicited time were judged as acceptable. Of the total of 3342 recordings stored, 2375 (71%) satisfied this criterion. Compliance was significantly less satisfactory in those referred by the Workers' Compensation Board (n = 11). CONCLUSION: In this survey of 21 subjects investigated for possible occupational asthma, compliance with PEF recording, as assessed by comparing recorded and stored results and the time at which the recording was solicited, was poor.

Adult↗
PubMed1995

Morphometry of small airways in smokers and its relationship to emphysema type and hyperresponsiveness.

Based on our previous finding, of increased small airways disease in centrilobular emphysema (CLE) when compared with panlobular emphysema (PLE), we hypothesized that smokers who develop CLE would have increased airway responsiveness associated with airway inflammation and exaggerated airway narrowing, but not smokers with PLE. We compared preoperative methacholine challenge with the morphologic and cellular inflammatory characteristics of the airways in the lungs of six nonsmokers, 10 smokers with CLE, and five smokers with PLE. The airways of the CLE group were narrower than those of the nonsmokers (KS < 0.05) and the PLE group (KS < 0.05), but perimeters were not different. A greater percentage of airways in the CLE group showed infolding of the epithelium and lumen deformity than in the PLE group and nonsmokers (p < 0.05). Airway inner wall thickening (WI) was increased in the CLE group when compared with the PLE group and nonsmokers (p < 0.05), and WI correlated significantly with PC20 in the CLE group (r = -0.64, p < 0.01) but not in the PLE group and nonsmokers. The number of T lymphocytes in the airway walls correlated with PC20 in the CLE group (r = -0.50, p < 0.05) but not in the PLE group. In conclusion, despite similar age, smoking history, and range of airflow limitation, there was a clear difference in the methacholine responsiveness between the emphysema groups, suggesting that responsiveness is not just a reaction to smoking but either a reaction developing in some smokers or an abnormality initially present in some smokers which, in combination with exposure to cigarettes, determines the development of a type of lung disease: CLE.

Aged↗
PubMed1995

Alveolar inflammation and its relation to emphysema in smokers.

The prevalent theory in the pathogenesis of emphysema proposes that increased numbers of activated neutrophils and/or alveolar macrophages produce large amounts of proteases, an activity that cannot be regulated by alpha 1-antiproteases, resulting in lung destruction. However, the cells in the lung parenchyma of smokers have not been properly identified. We characterized and quantitated the inflammatory cell load in the lungs of smokers and correlated these findings with the degree of lung destruction. Twenty-one patients, six nonsmokers and 15 smokers, undergoing lung resection were studied. Lungs or lobes were fixed and stained for light microscopy and neutrophil identification and immunohistochemically stained for identification of lymphocytes and macrophages. By point counting, we determined the extent of emphysema by the volume density of the lung parenchyma (Vvalv), and the different cell numbers per cubic millimeter in all lungs. In nonsmokers Vvalv was greater than in smokers. The number of neutrophils/mm3 of lung correlated directly with the Vvalv, (r = 0.71, p < 0.01), whereas the number of alveolar macrophages (r = -0.70) and T-lymphocytes (r = -0.78) correlated negatively with the Vvalv. The number of T-lymphocytes correlated negatively with the number of neutrophils (r = -0.58) and positively with the numbers of alveolar macrophages (r = 0.77). Our data suggest that as long as the inflammatory reaction is predominantly of neutrophils there is no destruction of the lung. However, the extent of lung destruction becomes evident, and its extent is directly related to the number of alveolar macrophages and T-lymphocytes/mm3. We conclude that the T-lymphocyte might be importantly implicated in the pathogenesis of emphysema in smokers.

Adult↗
PubMed1995

The reversibility of airway obstruction to an inhaled beta 2-adrenergic agent is less satisfactory after methacholine testing in asthmatic subjects.

AIMS: The aim of this work was to compare the response to an inhaled beta 2-adrenergic agent in two situations: (1) spontaneous airway obstruction in asthmatic subjects who had withheld treatment with the medication for more than 12 hs; and (2) after methacholine-induced airway obstruction once airway caliber had recovered to the premethacholine test value. SUBJECTS AND METHODS: Sixteen asthmatic subjects who showed a 20% or more improvement in FEV1 after inhaled beta 2-adrenergic agent (B2) (salbutamol, 200 micrograms) entered a double-blind crossover randomized trial in which the following tests were carried out: (1) FEV1 response after inhaling a placebo or active B2; (2) FEV1 response after inhaling a placebo or active B2 after a methacholine test that had induced a 20% or more reduction in FEV1, once FEV1 had recovered to the premethacholine value after inhaling salbutamol in an open fashion. RESULTS: As expected, the mean percent improvement in FEV1 in the spontaneous airway obstruction situation was 21.7 +/- 8.5% after inhaling the active B2 and 2.2 +/- 1.8% after placebo B2 (p < 0.001). Following recovery after methacholine challenge, the FEV1 was slightly superior (mean difference of 146 mL) to the premethacholine value before inhaling the active or placebo B2. In this situation, the percent improvement in FEV1 after inhaling the active B2 was only 7.5 +/- 4.4% and not significantly different from after inhaling placebo B2 (4.9 +/- 5.4%). Consequently, the end FEV1 value after inhaling active B2 was significantly higher in a situation of spontaneous airway obstruction than after methacholine-induced airway obstruction (mean difference = 110 mL; p = 0.02). CONCLUSION: After a methacholine test, the reversibility of an inhaled beta 2 agent is not significantly different from a placebo and is less satisfactory than in a situation of spontaneous airway obstruction. The mechanism for this needs to be explored but it is not secondary to persisting airway obstruction.

Adult↗
PubMed1994

Comparison of circadian variations using FEV1 and peak expiratory flow rates among normal and asthmatic subjects.

BACKGROUND: Most studies that describe circadian variations in asthma have used maximum rate of peak expiratory flow (PEF) rather than forced expiratory volume in one second (FEV1) to assess airway calibre. This study was designed to assess circadian variations in PEF and FEV1 measured simultaneously and to compare variations in these measurements in normal and asthmatic subjects in a stable clinical state. METHODS: Twenty nine subjects (nine asthmatic subjects on bronchodilators, 10 on inhaled steroids, and 10 normal controls) were asked to record their PEF and FEV1 with a new portable instrument every two hours during the day and once on waking at night for two weeks. Circadian variations were examined in different ways using arithmetical indices and cosinor analysis. RESULTS: 78% of PEF values and 75% of FEV1 values were considered to be reproducible and were included in the analysis. Variations obtained using PEF did not differ from those obtained using FEV1. Significant cosinor variations were found in at least 50% of recording days for most of the subjects and showed the same features as for arithmetical indices. Daily variations in PEF and FEV1 were significantly correlated with airway calibre and PC20 methacholine (r approximately 0.5 to approximately 0.6). CONCLUSIONS: PEF is as satisfactory as FEV1 for describing circadian variations among normal subjects and stable asthmatic subjects.

Adolescent↗
PubMed1994

Aluminium potroom asthma confirmed by monitoring of forced expiratory volume in one second.

Chronic airflow obstruction has long been seen among aluminium potroom workers. Currently referred to as "potroom asthma," it is debatable as to whether it is occupational asthma or nonspecific airway obstruction. A 35-yr-old male lifelong nonsmoker, with no history of asthma or atopy, was hired by an aluminium plant that had begun its operation in 1986. Preemployment screening, consisting of spirometry and a chest radiograph, was normal. During his 12-h shifts, he replaced 10 to 20 anodes (prebake type), spending 5 min each time close to open pots releasing hot fumes. The patient experienced episodes of cough and dyspnea, which were resolved during withdrawal from work in January and December 1991. He resumed work in the potrooms in March 1992, his dyspnea recurred at work and at night with 25% drops in peak expiratory flow rates (PEFR), associated with mild-to-moderate bronchial hyperresponsiveness (PC20 histamine, 1.0 mg/ml). After a chest physician's assessment, he was withdrawn from the potroom department. Assessment of the bronchial response to the occupational exposure in potrooms carried out in November 1992 revealed a pattern of dual asthmatic response, paralleled by a drop in PC20 methacholine from 5.1 to 0.7 mg/ml. A similar pattern was seen again during repeat workplace challenges 3 wk later. Spirometry obtained on control days was stable. We conclude that asthmatic reactions can exist among workers in aluminium smelters.

Adult↗
PubMed1994

Extent of centrilobular and panacinar emphysema in smokers' lungs: pathological and mechanical implications.

In order to quantify the extent of centrilobular (CLE) and panacinar (PLE) emphysema and the degree of the possible overlap between the two forms in smokers, the lungs of 25 smokers undergoing lung resection for peripheral lung tumours were studied. The extent of CLE and PLE was assessed by point counting, and the lungs were classified as having pure CLE (C, n = 5), predominant CLE with areas of PLE (CP, n = 7), predominant PLE with features of CLE (PC, n = 7), and pure PLE (P, n = 6) according to the percentage of lung involved by either form. Preoperative pulmonary function tests and the score of inflammation and the diameters of the small airways were also measured. Mean linear intercept (Lm), a measure of mean interalveolar wall distances and forced expiratory volume in one second (FEV1) were similar in the four groups. Small airway pathology was a predominant feature in lungs with CLE, and was significantly decreased in a stepwise fashion as the amount of PLE increased. This was especially so for the amount of muscle in the airway wall and the diameters of the airways. By contrast, lung compliance was higher in panacinar than in centrilobular emphysema.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

[Effect of an inhaled beta-2-adrenergic agent administered at the time of delayed bronchial reactions to occupational agents].

We previously showed in a retrospective study that the acute response to an inhaled beta-2-adrenergic agent is marked in late asthmatic reactions (J Allergy Clin Immunology 1990;85:834). In a double-blind prospective study, we assessed the magnitude and duration of the effect of inhaled salbutamol (200 micrograms) compared to a placebo in 22 subjects who experienced late asthmatic reactions (sustained fall in FEV 1 > or = 20%) after specific inhalation challenges in the laboratory with various occupational agents (isocyanates in 9 subjects). Before salbutamol was administered, the % in FEV1 over the pre-challenge values did not differ between the placebo (31 +/- 8%, n = 12) and the active (28 +/- 6%, n = 10) groups. The % recovery in FEV1 over the pre-bronchodilator value was 9 +/- 11% in the placebo group and 28 +/- 11% in the active group (t = 4.0, p < 0.001). The % recovery in FEV1 assessed in comparison with pre-challenge values was up to 80 +/- 17% in the placebo group and up to 95 +/- 6% in the active group (t = 2.85, p < 0.01). The 10 subjects on active medication had FEV1 values > or = 80% of the pre-challenge value one hour after inhaling salbutamol. The pattern of diminution in the bronchodilator effect was similar in the eight subjects with occupational asthma on active medication who remained for more than one hour as compared to a control group of asthmatic subjects paired for the degree of baseline airway obstruction. These data show that late asthmatic reactions are satisfactorily reversed with inhaled bronchodilator and that the duration of the effect is as satisfactory for subjects with occupational asthma as it is for asthmatic subjects.

Administration, Inhalation↗
PubMed1993

Exposure to domestic animals and risk of immunologic sensitization in subjects with asthma.

BACKGROUND: The objective of the study was to determine whether exposure to domestic animals plays a significant role, beyond atopy, in the development of immediate sensitization to animal-derived antigens. METHODS: To test this hypothesis, 200 subjects with asthma (85 male subjects and 115 female subjects; mean age, 37 +/- 16 years) seen consecutively in an asthma clinic were enrolled in a cross-sectional survey. Each subject answered a questionnaire about allergy symptoms and past and current exposure to domestic animals. Skin prick testing with extracts of common inhalant allergens including antigens from eight species of animal (cat, dog, horse, rabbit, rat, mouse, guinea pig, and hamster) were also carried out. RESULTS: Seventy-nine percent of subjects were atopic, and 91% had kept animals at home at some point (figures were 80% for dogs, 68% for cats, 23% for rabbits, and 20% for rodents). Using two-by-two tables, we showed that skin reactivity to at least one animal antigen was strongly linked to atopy (86% of atopic subjects had skin reactions as compared with 34% of nonatopic subjects: p < 0.001) but not to previous and current exposure to domestic animals (78% of both exposed and never exposed subjects). However, with the use of logistic regression, the determinants of skin reactivity to animals were atopy (p < 0.001), followed by cumulative duration of exposure to domestic animals (p < 0.01). The number of animals times the number of species times the duration of exposure was also a significant determinant of skin reactivity (p = 0.05). CONCLUSIONS: We conclude that beyond the predominant role of atopy, cumulative duration of exposure to domestic animals is a significant determinant for immediate sensitization to animal-derived antigens in subjects with asthma.

Adult↗
PubMed1993

Response to isocyanates: effect of concentration, duration of exposure, and dose.

There is no information on the relative role of dose, concentration, and duration of exposure in determining the magnitude of the bronchial response in subjects with isocyanate-induced asthma. Four subjects with asthma induced by toluene diisocyanate (TDI) were challenged using a recently described closed-circuit exposure chamber in which stable concentrations of TDI monomer can be generated. Each subject was challenged using various concentrations and durations of exposure on separate days. They were all exposed on three to four occasions to the same dose that had been shown to cause a 20% fall in FEV1 at a concentration of 15 ppb (DR15ppb) by varying the concentration (5, 10, 15, and 20 ppb) and durations (1 to 90 min), making sure that the total dose (concentration x duration) remained constant. They were also exposed to lower total doses by modifying the concentration and the duration on the remaining visits. Exposing subjects to the same DR15 ppb by modifying the concentration or the duration resulted in falls in FEV1 > or = 20%, except in one instance. Exposing subjects to doses lower than DR15 ppb, even at higher concentrations or for longer periods than in the challenges used for obtaining the DR15 ppb always caused falls in FEV1 < 20%. We conclude that the main determinant of bronchial responsiveness to TDI is not concentration nor duration of exposure per se but the product of both factors, that is, total dose.

Adult↗
PubMed1993

Duration of effect of loratadine and terfenadine administered once a day for one week on cutaneous and inhaled reactivity to histamine.

STUDY OBJECTIVE: The duration of action of several new non-sedative antihistamine preparations as assessed by skin and bronchial reactivity to histamine has still not been well established. The aim of the study was to evaluate the duration of effect of loratadine (10 mg) and terfenadine (120 mg) administered once a day for one week on cutaneous and inhaled reactivity to histamine by comparison with a placebo. SUBJECTS: Twenty-four adult asthmatic subjects were included in a parallel group study that compared the duration of effect of two antihistamines and a placebo on cutaneous and inhaled reactivity to histamine. STUDY DESIGN: Baseline cutaneous and inhaled reactivity (concentration causing a fall of 20 percent in FEV1 [PC20]) to histamine was obtained on three consecutive days. Loratadine (10 mg), terfenadine (120 mg) and a placebo loratadine were administered daily for 1 week to 3 groups of subjects. The PC20 was measured at the end of the medication period, 3 days later, and weekly until PC20 returned to baseline value (upper limit of 2 SD from the mean baseline value). RESULTS: The mean blocking duration on cutaneous reactivity for loratadine was 6.9 days and for terfenadine, 7.2 days. The mean duration of the blocking effect on PC20 histamine was 8.5 days for loratadine and 7.2 days for terfenadine. These figures were significantly longer than for the placebo. CONCLUSION: These data suggest that terfenadine and loratadine have a comparable blocking effect on reactivity to cutaneous and inhaled histamine. A daily dose taken for one week will result in a mean blocking effect of one week.

Administration, Inhalation↗
PubMed1993

[The Quebec system of indemnification for occupational asthma. Description, efficacy, and costs].

This study describes the Quebec system of compensation for occupational asthma, assessing the functional and social outcome of claimants and estimating the efficiency and cost. Information was obtained on the clinical, functional and social outcome as well as the estimated costs for 134/211 subjects (participation rate of 64%), who received compensation between 1986 and 1988. At the time of assessment (2 years and more after the diagnosis), 93% of participants still demonstrated significant bronchial hyperresponsiveness and 84% required anti-asthma medication. None of the participants remained exposed to the offending agent: 67% were working for the same or another employer, 16% were retired, 8% were retraining for a new job and 8% were still unemployed. Quality of life was mildly affected, more so than for a control group of subjects. The mean interval between the time claims were addressed and the first medicolegal decision was 8.1 months. The mean total cost (including temporary and permanent disability indemnities, medical and technical costs) was $CAN 49,200 (minimum and maximum values of $2,100 and $330,900). We conclude that for subjects with occupational asthma in Quebec: 1) the mean interval for a medicolegal decision to be made is eight months: 2) a minority is still unemployed two to four years after being assessed; 3) the quality of life is more affected than in a control group; 4) the mean cost is close to $CAN 50,000.

Activities of Daily Living↗
PubMed1992

Salmeterol, a new inhaled beta 2-adrenergic agonist, has a longer blocking effect than albuterol on hyperventilation-induced bronchoconstriction.

The duration of the blocking effect of salmeterol (50 micrograms), albuterol (200 micrograms), and a placebo were compared in a double-blind study in 12 adult subjects with asthma who underwent hyperventilation tests with cold dry air (-20 degrees C) on 4 study days. On the first day, the hyperventilation test was performed at various time intervals (baseline, 1, 4, 6, 8, 12, and 24 hours) with spontaneous functional recovery between each test to determine the within-day within-subject variability of the response. The response was assessed by interpolating the dose of cold dry air causing a 20% fall in FEV1. On the 3 remaining days, separated by an interval of at least 5 days, the active or placebo medication was administered after spontaneous recovery from the first hyperventilation test. Spirometry was assessed 15 minutes and 1 hour later. The hyperventilation test was then performed and repeated 4 hours after administration of the drug. The test was repeated 6, 8, 12, and 24 hours later to detect any significant blocking effect. The improvement in FEV1 15 minutes and 1 hour after the drug was administered was 19.8% and 20.4%, as compared to baseline for albuterol, and 16.3% and 16.8% for salmeterol (not significant). The mean duration of the blocking effect was 0.25 hour for the placebo, 3.5 hours for albuterol, and 15.9 hours for salmeterol (F = 24.5; p less than 0.001; Newman-Keul's test was significant for every contrast). Eight of the 12 subjects still demonstrated some blocking effect 8 hours after taking salmeterol; this was true for only one subject receiving albuterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Natural history of occupational asthma: relevance of type of agent and other factors in the rate of development of symptoms in affected subjects.

It is unknown whether factors such as the nature of the agent, gender, age, atopy, smoking habits, continuous or noncontinuous exposure, and pattern of asthmatic reaction can influence the rate of development of symptoms in subjects with occupational asthma. We compared several clinical and functional parameters among three groups of subjects with occupational asthma caused by Western red cedar (group 1, n = 433), isocyanates (group 2, n = 107), and high molecular weight agents acting through an IgE-mediated mechanism (group 3, n = 121). Survival analysis showed that the three curves relating years of exposure before onset of symptoms to the proportion of subjects without symptoms were significantly different in two respects: (1) almost 40% of subjects in groups 1 and 2 as compared with 20% of subjects in group 3 became symptomatic within 1 year of exposure; (2) after 5 years of exposure, the rate of sensitization was slower for subjects in groups 2 and 3 as compared with those in group 1. Having a nonimmediate reaction at the time of specific inhalation challenges, being continuously exposed and being younger slightly increased the risk at each time point on the curve of developing symptoms in subjects with occupational asthma. These data suggest that the natural history for onset of occupational asthma is different depending on the sensitizing agent. Factors such as age, type of exposure, and pattern of reaction on exposure to the agent also modulate the rate of development of this condition.

Adult↗
PubMed1992

Morphometric changes during the early airway response to allergen challenge in the rat.

The purpose of this study was to determine the relative contributions of airway wall edema and smooth muscle contraction to the early response (ER) of allergic bronchoconstriction. Brown Norway rats, 6 to 7 wk old, were sensitized with ovalbumin (OA). Anesthetized rats were challenged with either OA or saline 2 wk later. Pulmonary resistance (RL) was measured every minute until either it increased to 150% of the baseline, defined as a significant ER, or until 15 min elapsed. Eight OA-challenged test rats with a significant ER and eight saline-challenged control rats were used for morphometric studies. The lungs were quick-frozen with liquid nitrogen, processed with freeze substitution, and sagittal sections (5 microns) were stained with hematoxylin and eosin. The airway lumen subtended by the epithelial basement membrane (LuB) and cross sectional airway wall area (AW) of all airways were measured by camera lucida and digitization. The LuB and AW of each airway was standardized for size by dividing by the ideal airway lumen (LuBideal), which was calculated from the length of basement membrane, assuming a perfect circle in the unconstricted state. The cumulative frequency distribution of the LuB/LuBideal for the airways from test rats was shifted to the left compared with the control rats (p less than 0.01), indicating airway narrowing after challenge. Airway narrowing increased as a function of airway size. Cumulative frequency distributions of AW/LuBideal showed that there was a significant increase in the wall thickness of only the small airways of test animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗