Effect of sodium cromoglycate on histamine inhalation tests.

Sixteen adult asthmatic subjects in a clinical steady state were included in the study. On day 1, after baseline assessment of spirometry (FEV1, FEV1/FVC, FEF25-75), they underwent three to four consecutive inhalation tests using twofold increasing doses of histamine to measure the provocative concentration causing a fall in FEV1 of 20% (PC20). Baseline FEV1 was back to +/- 5% of the initial assessment before each histamine inhalation test (HIT).

Nonallergic bronchial hyperexcitability in chronic bronchitis.

The aim of this study was to assess responsiveness to inhaled histamine and methacholine using PC20, the concentration causing a 20% fall in forced expiratory volume in one second (FEV1) in 28 subjects with chronic bronchitis excluding asthma. Eighteen subjects had airway hyperexcitability, as demonstrated by a PC20 less than 16 mg/ml. The response to histamine and methacholine was not significantly different and the correlation coefficient was 0.

Bronchial responsiveness to methacholine and effects of respiratory maneuvers.

Eight asthmatic and six normal subjects had methacholine chloride inhalation tests on two visits. On first assessment the provocative concentration causing a 20% fall in forced expiratory volume in 1 s (PC20FEV1) was measured. On the second visit the provocative concentration causing a 35% fall in specific lung conductance (PC35sGL) was obtained in addition to the PC20FEV1.

Combined alveolitis and asthma due to hexamethylene diisocyanate (HDI), with demonstration of crossed respiratory and immunologic reactivities to diphenylmethane diisocyanate (MDI).

A worker exposed intermittently to hexamethylene diisocyanate (HDI) developed episodes of dyspnea, wheezing, and fever on working days. Complete lung function tests performed when the subject was asymptomatic were normal except for increased airway responsiveness to histamine, which significantly improved after a 3 wk period off work. At that time, specific inhalation challenges with HDI were carried out.

Circadian variations of airway response to histamine in asthmatic subjects.

In 15 clinically stable asthmatic subjects, histamine inhalation challenges were carried out on six different days, at 8, 16 and 22 h, twice at each time. On each visit, baseline functional measurements including FEV1 and forced mid-expiratory flow rates (FEF25-75%) were followed by the assessment of the concentration of histamine causing a 20% fall in FEV1 (PC20). There was no significant difference in baseline lung function tests and PC20 for visits done either at the same or different times.

Reference values of the provocative concentrations of methacholine that cause 6% and 20% changes in forced expiratory volume in one second in a normal population.

The provocative concentrations of inhaled methacholine that cause 6% (PC6) and 20% (PC20) falls in forced expiratory volume in one second (FEV1) were assessed in a population of 100 nonsmoking persons, equally distributed for sex, who ranged uniformly from 20 to 60 yr of age. These subjects had no respiratory symptoms, rhinitis, atopic history, or familial history of asthma. Single twofold dilutions of methacholine from 2 to 128 mg/ml were used; 81 and 34 subjects, respectively, showed PC6 and PC20 values less than 128 mg/ml.

Histamine dose-response curves in asthma: reproducibility and sensitivity of different indices to assess response.

In 18 clinically stable asthmatic patients histamine inhalation challenges were performed with a Wright's nebuliser and tidal volume breathing for two minutes on two to four occasions for each subject at a maximum interval of two weeks. The response was measured in terms of specific lung conductance (sGL) by the subtraction technique, maximum partial and maximum complete expiratory flow at 40% and 50% of vital capacity respectively (Vmax40p and Vmax50c), and FEV1 from the maximum flow-volume curve. Dose-response curves were analysed for (1) provocative concentration (PC) of histamine causing a 20% fall in FEV1 and a 40% change in the other measurements; (2) threshold concentration (TC)--the concentration at which changes in the measurement exceed 2 SD from control values; (3) reactivity (R)--the slope of the dose-response curve beyond TC.

Time course of the bronchoconstriction induced by inhaled histamine and methacholine.

Eleven asthmatic subjects inhaled doubling concentrations of histamine until a near sixfold increase in total pulmonary flow resistance had been reached. This last concentration (C6) of histamine and methacholine was administered on two subsequent separate visits. Specific lung conductance (sGL) dropped to 18.

Bronchial responsiveness to inhaled methacholine in young asymptomatic smokers.

Methacholine inhalation challenges were performed in 10 young smokers who denied having respiratory symptoms and in 10 nonsmokers of the same age. There were five males and five females in each group. The bronchoconstriction was evaluated with specific lung conductance (sGL), maximum partial (initiated from end-inspiratory lung volume) expiratory flows assessed at 40% vital capacity breathing air (Vmax40p air), and a He-O2 mixture (Vmax40p He), and with maximum complete flows breathing He-O2 [forced expiratory volume at 1 s (FEV1), Vmax50c He].

Occupational hypersensitivity pneumonitis after exposure to diphenylmethane diisocyanate.

A foundry worker developed dyspnea and a restrictive breathing defect after being exposed to diphenylmethane diisocyanate (MD) at work. His symptoms and lung function impairment subsided a few weeks after he left work. Specific inhalation challenges with the offending agent induced general malaise together with a significant increase in body temperature and leukocyte count as well as a significant decrease in forced vital capacity and transfer factor.

Occupational asthma caused by nickel sulfate.

A 28-yr-old man developed asthma shortly after being exposed to nickel sulfate (NiSO4) in a metal-plating factory. Recordings of peak expiratory flow rates at work and for an off-work period showed increased variations at work, with best values on weekends. Allergy prick skin tests elicited an immediate reaction with NiSO4 at a concentration of 10 mg/ml.

Histamine dose-response curves in asthma: relevance of the distinction between PC20 and reactivity in characterising clinical state.

The aim of the present study was to determine if the measurement of the slope of teh histamine dose-response curve (bronchial reactivity) could provide useful information on the clinical state of asthma. Fifteen adult asthmatic subjects were studied twice at an interval of one year. Their clinical state was assessed by comparing their respiratory symptoms, need for medication, and FEV1 on both visits.

Prevalence of precipitating antibodies to different extracts of Aspergillus fumigatus in a North American asthmatic population.

This study was carried out to find the prevalence of precipitin reactions in the sera of 200 North American asthmatic subjects. Precipitins were detected by the double diffusion technique using different extracts of Aspergillus fumigatus, including a reference 'home produced' extract and five commercial extracts from three different suppliers. In addition, antigenicity of these extracts was assessed by crossed immunoelectrophoresis (XIE).

Rapid gentamicin elimination in obstetric patients.

Wide interpatient variation in gentamicin elimination rates and dosage requirements was demonstrated in 67 obstetric patients with normal serum creatinine levels. A poor correlation occurred between the elimination rate of gentamicin and creatinine clearance (r = .23).

Acute bronchoconstriction caused by Beclovent and not Vanceril.

A 24-year-old asthmatic patient reported acute wheezing immediately after using an aerosol of beclomethasone dipropionate (Beclovent). She was hospitalised for bronchial challenges. Immediate bronchoconstriction was shown after two puffs of this aerosol and after inhalation of the placebo containing all the products of the aerosol less the beclomethasone.

Comparison of histamine bronchial challenges with the Wright nebulizer and the dosimeter.

In twenty adult asthmatics studied in a stable state, histamine bronchial challenges were carried out at one-week intervals with the Wright nebulizer and with the dosimeter-DeVilbiss apparatus. Dose-response curves were analysed for sensitivity, defined as the minimal histamine dose causing a 20% fall in FEV1 (PC20), and for reactivity, defined as the slope of the dose-response curve once the reaction starts to occur. A significant relationship (r=0.

Incidence of immediate sensitivity to Aspergillus fumigatus in a North American asthmatic population.

Allergic bronchopulmonary aspergillosis might be less frequent in North America because the incidence of immediate sensitivity by asthmatics to A. fumigatus is less. In order to check this hypothesis, 200 asthmatics were skin tested with two extracts of A.