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Biomedical subjects

A Cartier

Publications and source records attributed to A Cartier.

At least 127 records · Page 7Linked to original sources
PubMed1990

Prevalence of occupational asthma and immunologic sensitization to psyllium among health personnel in chronic care hospitals.

Psyllium is a high molecular weight laxative that can cause occupational asthma among health care workers who prepare this product for chronically ill patients. The prevalence of immunologic sensitization and occupational asthma to psyllium is unknown. We investigated the personnel of four chronic care hospitals, including two where four cases of occupational asthma had been confirmed the year preceding the trial. A questionnaire and skin prick tests with psyllium and various inhalants were administered to 193 of 248 (78%) of the workers who agreed to participate. Seventy-five subjects (39%) had a history of respiratory symptoms in normal life and/or respiratory symptoms and/or rhinoconjunctivitis after handling psyllium. Six (3%) showed skin reactivity to psyllium. Increased specific IgE antibodies were found in 20 of 162 of the sera that were tested (12%). In the second part of the study, a histamine inhalation challenge was performed on 70 of 75 (93%) of the subjects with a history suggestive of asthma and/or occupational asthma and/or skin reactivity to psyllium. Twenty (29%) had significant bronchial hyperresponsiveness. The six subjects with a history suggestive of occupational asthma (n = 3) and/or asthma (n = 6) and/or positive skin test results to psyllium (n = 6) had significant bronchial hyperresponsiveness and increased specific IgE levels. They all underwent specific inhalation challenges with psyllium in the laboratory. Four developed bronchospastic reactions (two immediate and two dual reactions). We conclude that by including the initial four cases reported in the year preceding the initiation of this trial, the prevalence of IgE sensitization to psyllium was between 5 (skin testing) and 12% (increased specific IgE levels).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Medico-legal statistics on occupational asthmna in Quebec between 1986 and 1988].

The authors have carried out a statistical analysis of cases of occupational asthma and other occupational lung diseases submitted to the Ministry of Labour in Quebec between 1986 and 1988. The total number of claims was 913, 993, and 866 respectively for the 3 years of which 61% to 71% were accepted. 41% to 55% were new assessments. Of 228 new claims accepted in 1988, 81 (36%) were for occupational asthma. This number surpassed the number of claims accepted for traditional pneumoconiosis (asbestos = 30, and silicose = 36). Isocyanates were the principle cause of occupational asthma (23% of cases were recognised in 1988) followed by flour, red and white cedar, snow crab process workers, and various pharmaceutical products and grains. In comparison with statistics in 1977, one noticed there was a large reversal of the frequency of certain occupational lung diseases that are recognised, because at that time asbestosis and silicosis were the principle causes of claims put forward and accepted. The authors discuss the statistical bias of occupational lung disease obtained by medico-legal agencies. Although occupational asthma has not been the object of the systematic screening program in the work place and although there is a tendency for workers to avoid or abandon their occupation more often than in the traditional pneumoconioses current protection is sufficient in Quebec to motivate individuals who are possibly suffering from occupational asthma to put in a claim for compensation.

Asthma↗
PubMed1990

Comparative effects of volume history on bronchoconstriction induced by hyperventilation and methacholine in asthmatic subjects.

The aim of this study was to find out if bronchodilatation following deep inspiration can be induced by the inhalation of a "natural" stimulus (hyperventilation of cold dry air), and if the effect is similar to that induced by methacholine. After baseline assessment of lung resistance (RL), 10 asthmatic subjects were asked to inhale cold dry air for 3 min. RL was monitored continuously for 3-4 min, at which time subjects were asked to take a fast deep inspiration. After recovery, the manoeuvre was repeated and RL was reassessed. The manoeuvre was then repeated a third time. After functional recovery, progressive doses of methacholine were inhaled until the increase in RL was comparable to that obtained after hyperventilation (56 +/- 16% and 65 +/- 24%, respectively, mean +/- SD, NS). The same deep inspiration manoeuvre was repeated three times with recovery as after hyperventilation of cold dry air. Maximum changes in RL were not significantly different after each of the three manoeuvres for either type of bronchoconstriction. The mean fall in RL was 14.2 +/- 9.9% after hyperventilation and 16.4 +/- 10.5% after methacholine. There was a satisfactory correlation (r = 0.80, p less than 0.01) between the bronchodilatation after deep inspiration for both types of stimuli. We conclude that the bronchodilator effect of deep inspiration is no different using either a pharmacological stimulus (methacholine) or a "natural" stimulus (hyperventilation of unconditioned air). These results show that assessing the response to hyperventilation with manoeuvres requiring deep inspiration, forced expiratory volume in one second (FEV1) may alter airway tone in a way similar to pharmacological stimuli.

Asthma↗
PubMed1990

Acute lung reaction due to zinc inhalation.

A 27-yr-old man began work at a company that produces concrete pipes in April 1987. The pipes are linked with rings covered with zinc. In September 1987, he was transferred to a new job in the same plant where he had to heat zinc wires and shoot the heated zinc in powder form onto the iron rings. He had no past personal nor family atopic history. Two weeks after he began in his new job, he experienced an episode of chills with muscle aches and dyspnoea at the end of a working day. The fever persisted until the next day, at which time he saw a physician. A chest radiograph revealed diffuse interstitial shadows. He was off work for 10 days. His symptomatology disappeared and his chest radiograph cleared. He went back to work and experienced a similar episode. He remained away from work for one month, after which specific inhalation challenges were performed. On a control day, there were no significant changes in forced expiratory volume in one second (FEV1), forced vital capacity (FVC), or buccal temperature. Two white blood counts (WBC) showed 8,400 and 8,500 white cells. He was exposed to his usual work environment for one hour on two consecutive days. On both occasions, there were significant falls in FEV1 (16% and 20%) and FVC (10% and 11%), occurring 4-6 h after exposure. Buccal temperature reached 38.1 and 38.7 degrees C on the two occasions, and WBC were 17,000 and 15,900 at the end of each day. Precipitins were negative and specific IgG antibodies could not be detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Specific serum antibodies against isocyanates: association with occupational asthma.

Although increased levels of specific IgE and/or IgG antibodies have been documented in individual cases of occupational asthma caused by common types of isocyanates (hexamethylene diisocyanate [HDI] and diphenylmethane diisocyanate [MDI]), the frequency among workers with occupational asthma is still unknown. The sera of 62/65 workers referred for specific inhalation challenges with isocyanates were analyzed for the presence of specific antibodies to the relevant isocyanate. Most workers (39, 63%) were exposed to HDI, some to MDI (17, 27%), and a few to toluene diisocyanate (six, 10%). Specific inhalation challenges were positive in 29 subjects, eliciting either immediate (seven), early late (two), late (13), or dual (seven) reactions. Specific inhalation challenges were more often positive in those subjects with increased nonspecific bronchial responsiveness. Twenty-nine subjects demonstrated increased levels of specific IgE and/or IgG antibodies to isocyanates in the absence of antibodies against human serum albumin (increased IgE only, no subject; IgG only, 20; both IgE and IgG, nine subjects). Although there was a loose association between the results of specific inhalation challenges and levels of specific IgE, the association was much better with the level of specific IgG. Indeed, 21 of the 29 subjects (72%) with positive challenges had increased levels of specific IgG, whereas 25 of the 33 subjects (76%) with negative challenges had normal levels of antibodies. The association was significant with both HDI and MDI. The levels of antibodies were not significantly associated with the type of temporal reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies↗
PubMed1989

Significant changes in nonspecific bronchial responsiveness after isolated immediate bronchospecific reactions caused by isocyanates but not after a late reaction caused by plicatic acid.

Although late bronchospastic reactions after exposure to antigenic and sensitizing agents usually significantly alter bronchial responsiveness to histamine or methacholine, presumably by causing bronchial inflammation, isolated immediate bronchospastic reactions do not induce such changes. We studied three subjects who demonstrated different patterns of reaction. The first individual was diagnosed as having occupational asthma to red cedar. This was confirmed by specific inhalation challenges that resulted in late bronchospastic reaction. No significant changes in the provocative concentration of histamine causing a 20% fall in FEV1 (PC20) were found 1 day after this reaction. Two weeks later, serial assessments (five and six, respectively) of PC20 histamine were recorded on control days and up to 48 hours after exposure to plicatic acid, which caused a late bronchospastic reaction with a maximum fall of 37% in FEV1. No significant changes in PC20 were found; the maximum variations on control days were 0.36 to 0.74 mg/ml, and on active days, from 0.37 to 0.59 mg/ml. By contrast, two other subjects, who demonstrated isolated immediate reactions after exposure to diphenylmethane diisocyanate, had significant changes in PC20 histamine and methacholine, in one subject from 3.1 mg/ml to 0.6 mg/ml 8 hours after exposure, and in the other subject, from 61.0 to 7.4 mg/ml 7 hours after exposure, with recovery during the next few days. These examples demonstrate that the pattern of nonspecific bronchial responsiveness after immediate and late bronchospastic reactions can be different from what has previously been described. Immediate bronchospastic reactions may lead to bronchial hyperresponsiveness, whereas late asthmatic reactions do not always induce changes in bronchial responsiveness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Inhaled lignocaine does not alter bronchial hyperresponsiveness to hyperventilation of dry cold air in asthmatic subjects.

It has been hypothesized that bronchoconstriction due to exercise and hyperventilation is caused by the stimulation of irritant receptors in the upper airways. However, controversial results have been reported on the effect of lignocaine, which can inhibit the stimulation of these receptors. The aim of this study was to investigate the effect of inhaled lignocaine on bronchial responsiveness to hyperventilation of cold dry air in asthmatic subjects. Eight adult asthmatic subjects in a clinical steady state came on four different days (two placebo and two active days in random order) with a maximum interval of 3 weeks. After assessment of forced expiratory flow rates, inhalation of either phosphate-buffered saline (placebo) or lignocaine solution (40 mg) was carried out in a single-blind fashion. The technician was not aware which medication was being inhaled, but the asthmatic subject knew which drug it was by the sensation in his or her throat. Forced expiratory flow rates were reassessed 15 min after the nebulization; then, the subjects were asked to inhale cold dry air (-20 degrees C) in progressively increasing levels of ventilation (7.5, 15, 30 and 60 l/min and maximum voluntary ventilation). PD20 was interpolated from the dose-response curve, relating the dose of cold air on a non-cumulative logarithmic scale on the abscissa and the percentage change in FEV1 on the ordinate. There were no significant changes in FEV1 and PD20 after inhalation of lignocaine as compared to the placebo. We conclude that inhaled lignocaine does not significantly alter bronchial hyperresponsiveness to hyperventilation of cold air in asthmatic subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1989

Four-times-a-day dosing frequency is better than a twice-a-day regimen in subjects requiring a high-dose inhaled steroid, budesonide, to control moderate to severe asthma.

Fifty-three adult asthmatic subjects requiring 800 micrograms or more of inhaled beclomethasone dipropionate were enrolled in a double-blind parallel group study of 6-month duration to compare the efficacy and side effects of inhaled budesonide in doses of 800, 1,200, and 1,600 micrograms given two or four times a day (BID or QID). After a two-week observation period to establish baseline, subjects were given the same dose of budesonide as they would be for beclomethasone dipropionate; however, the frequency regimen (BID or QID) was randomly allocated. Subjects were asked to fill in diary cards describing their asthmatic symptoms, need for medication, and throat symptoms. They were assessed by a physician every 4 wk, at which time spirometry was performed. Throat swabs were done at every other monthly visit. Cortisol and response to cortisol after synthetic ACTH injection were assessed at the beginning and end of the trial. Thirty-six subjects, half in each group, completed the study. Those on the BID regimen had almost twice as many days with nocturnal asthma and cough and almost three times as many days with disability due to asthma. There were also twice as many relapses in the BID regimen as judged by the clinician. These relapses mainly occurred toward the end of the study. The maximal daily swings in peak expiratory flow rates were slightly greater in the BID group, although this difference was not physiologically significant. Spirometry, cortisol secretion, and the response after synthetic ACTH injection were not significantly different in either group from the beginning to the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1989

Duration of action of inhaled terbutaline at two different doses and of albuterol in protecting against bronchoconstriction induced by hyperventilation of dry cold air in asthmatic subjects.

Although several studies have examined the duration of the bronchodilator effect of several inhaled beta-2-adrenergic agents, the duration of the blocking effect on bronchial hyperresponsiveness, another key feature of asthma, has seldom been studied. We investigated this problem in eight adult asthmatic subjects who underwent hyperventilation tests with dry cold air on 4 different days. On the first day, five hyperventilation tests with assessment of the level of ventilation causing a 20% fall in FEV1 (PD20) were obtained to evaluate the within-day variability of the test. On the three other visits, after a baseline hyperventilation test, albuterol 200 micrograms, terbutaline 500 micrograms, and terbutaline 1,500 micrograms were administered in a double-blind, randomized way. Hyperventilation tests were carried out 1, 2, 4, and 6 h later. The blocking effect on the treatment days, as assessed by the differences in PD20 for each test compared with baseline PD20 for that day, was corrected for the within-day variability of the control day. There was a significant bronchodilator effect 1 h after administering the drug; it was equivalent for albuterol 200 micrograms (25.6 +/- 14.7%) and terbutaline 1,500 micrograms (21.7 +/- 13.5%) and significantly less for terbutaline 500 micrograms (14.1 +/- 10.0%). Complete or partial blockade on bronchial responsiveness was obtained in the majority (six to seven of eight) of the subjects 1 h after inhaling the bronchodilator, with progressive reduction in the effect later on. Four subjects still showed a blocking effect 6 h after terbutaline 1,500 micrograms was administered, one subject after terbutaline 500 micrograms, and no subjects after albuterol (chi square = 6.6, p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1989

Occupational asthma due to various agents. Absence of clinical and functional improvement at an interval of four or more years after cessation of exposure.

We have previously shown that in some subjects with occupational asthma caused by various agents, there is no improvement approximately two years after exposure ended. These results could be explained by the short interval between diagnosis and follow-up. In the current study, we saw 28 subjects with occupational asthma at two intervals, 2.3 years (range, three months to 5.7 years) and 5.8 years (range, 4.3 to 10.9 years) after the cessation of exposure. Various causes of occupational asthma were included. The diagnosis was confirmed in 26 of the cases by specific inhalation challenges in the laboratory, and in the remaining two cases by combined monitoring of peak expiratory flow rates and bronchial responsiveness. All subjects had symptoms of asthma at both follow-up assessments. There were no changes in the need for medication, spirometry, or bronchial hyperresponsiveness. Depending on the interval of the follow-up, four to six subjects required inhaled steroid agents in addition to the usual bronchodilators, 11 had FEV1 less than 80 percent of predicted, and 26 or 27 had an abnormal PC 20 histamine. Only two subjects demonstrated sustained improvement in PC 20 at the first and second follow-ups, and one other showed changes during the second follow-up assessment which were not present at the first. We conclude that except for three subjects, the need for medication did not diminish, nor did airway obstruction and hyperresponsiveness improve in this group of subjects with occupational asthma long after exposure ended. These results differ from other studies, which demonstrated that some recovery takes place in a greater proportion of individuals.

Asthma↗
PubMed1989

Occupational asthma caused by exposure to ash wood dust (Fraxinus americana).

A 63 year old man reported rhinitis and asthma, which occurred only at work where he was exposed to ash wood dust. Monitoring of peak expiratory flow rates (PEFR) and bronchial responsiveness to histamine when off work and at work showed increased variation of PEFR at work but no significant changes in nonspecific bronchial responsiveness assessed by the provocation concentration producing a 20% fall in FEV1 (PC20). Specific inhalation challenges were carried out in a special challenge room with ash wood dust. During the exposure for only 3 minutes, the mean concentration of particles was 3 mg-m3 and about 50% of particles had a diameter less than 10 mu. An immediate bronchospastic reaction was documented. Antibodies to a human serum albumin (HSA) ash wood conjugate were not significantly increased.

Asthma↗
PubMed1989

Influence of the duration of inhalation of cold dry air on the resulting bronchoconstriction in asthmatic subjects.

Hyperventilation of cold dry air causes bronchoconstriction in asthmatic subjects and has been proposed as a test for assessing bronchial hyperresponsiveness. The influence of the duration of inhalation of unconditioned cold air has not been studied. We have investigated the question in 12 asthmatic subjects in a clinically stable state. Each subject underwent three inhalation tests at a maximum interval of two weeks. On each day, the duration of inhalation was different, being randomly 2, 3 or 4 min depending on the subject. Doubling doses of cold air produced by a freon conditioner were administered, increasing ventilation from 7.5 to 15, 30, 60 l.min-1 and maximum voluntary ventilation (MVV). Forced expiratory volume in one second (FEV1) was assessed after each period of cold air inhalation. The test was stopped when the FEV1 had decreased by 20% or more, or when MVV had been achieved. The dose of cold air expressed as the level of ventilation causing a 20% change in FEV1 (PD20) was interpolated from individual dose-response curves. Dose-response curves shifted to the left when the duration of ventilation was increased. PD20 was significantly lower after 3 min of ventilation than after 2 min (mean +/- SD PD20 of 41.7 +/- 1.4 l.min-1 compared with 53.3 +/- 1.2 l.min-1; p = 0.002). There was a further fall in PD20 after 4 min of ventilation (PD20 = 36.1 +/- 1.5 l.min-1) but the difference compared with the values obtained after 3 min was not significant (p = 0.09), thus suggesting a plateau.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

New methodology for specific inhalation challenges with occupational agents in powder form.

Numerous agents in powder form (wood dust, flour, antibiotics, drugs, etc.) can cause occupational asthma. The diagnosis is generally confirmed by specific inhalation challenges in a special challenge room. There are several pitfalls to the procedure: 1) subjects may be exposed to high concentrations of particles; the concentrations of particles may be higher than the threshold limit value-short term exposure level (TLV-STEL), possibly resulting in severe or irritant reactions; 2) the exposure is erratic. To overcome these problems, a new device for aerosolization of powders has been developed. This apparatus consists of three parts: a particles generator, an aerosol delivery system connected to an orofacial mask, and monitors - a photometer and a cascade impactor. Information on the concentration and size distribution of inhaled particles can therefore be obtained. We performed specific inhalation challenges with this apparatus on 20 subjects suspected of having occupational asthma. The concentration of particles was generally below or close to the TLV-STEL and information was obtained on the proportion of particles with a diameter less than 10 mu. Falls in forced expiratory volume in one second (FEV1) were progressive with each increase in the duration of exposure. The five subjects who had negative reactions to exposure were asked to tip the relevant product from one tray to another in the traditional realistic way. All had negative responses. We conclude that this new procedure offers advantages over the traditional method as it gives information on the concentration and size distribution of inhaled particles and makes the drawing of a dose-response curve possible, both of which may improve the safety and accuracy of the test.

Adult↗
PubMed1988

Occupational asthma from reactivity to an alkaline hydrolysis derivative of gluten.

A 29-year-old female subject had been working for 13 years in a company producing biscuits. She was exposed intermittently to an alkaline hydrolysis wheat gluten derivative (AHGD) that was incorporated into marshmallows. Five years before being referred, she started reporting rhinoconjunctivitis and asthmatic symptoms immediately after handling AHGD. When she was first assessed, she had avoided contact with AHGD for 1 year, and she was asymptomatic. Normal spirometry and bronchial responsiveness to histamine (provocative concentration causing a 20% fall in FEV1, 22 mg/ml) were obtained. There was a positive allergy skin test to ragweed pollen and to AHGD at 0.01 mg/ml. Skin tests with individual extracts of cereals, including wheat, were negative. Inhalation challenge with AHGD for 15 seconds caused immediate rhinoconjunctivitis and bronchoconstriction (maximum fall of 40% in FEV1 30 minutes after the exposure) with complete recovery 2 hours later. There was no reaction thereafter, and the provocative concentration of histamine causing a 20% fall in FEV1 was not significantly changed (13.1 mg/ml) 9 hours after the challenge. Inhalation challenge with wheat flour containing native gluten for 30 minutes did not cause any symptoms or significant change in FEV1. IgE RAST counts were greater with the AHGD than with gluten and the whole wheat extract; the opposite was generally found with sera from individuals with baker's asthma and wheat food allergy. With the serum of the affected worker, AHGD completely inhibited the corresponding RAST, but gluten did not. With wheat food allergy, AHGD was relatively inactive inhibition of the wheat and gluten RAST, but gluten was effective.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Occupational asthma in workers of a pharmaceutical company processing spiramycin.

After investigation of one worker with occupational asthma, all 51 employees of a pharmaceutical company processing the macrolide antibiotic spiramycin were investigated to determine the frequency of the condition and the risk factors. The antibiotic was produced for short periods four to five times a year. The first part of the investigation, conducted before a production period, consisted of the following: questionnaire, skinprick tests, blood sample, spirometry, assessment of bronchial responsiveness to methacholine, and monitoring of peak expiratory flow rates (PEF). The second part of the survey was carried out in 48 of the 51 workers during the production period, and included the same assessments except for skin testing. No FEV1 values had changed by more than 9% or PEF by more than 19%. Inhalation challenge with spiramycin was performed in 12 of the 14 individuals who had a history of occupational asthma, a provocative concentration of methacholine (PC20) of 16 mg/ml or less, or a PC20 that fell by 2.5 fold or more during the production period (or a combination of these). Three subjects experienced immediate bronchoconstriction. All reported symptoms, and all had a fall in PC20 methacholine during the production period. It is concluded that the minimum frequency of occupational asthma in this company processing spiramycin is 4/51 (7.8%). The combination of a positive response to the questionnaire and a change in bronchial hyperresponsiveness during the production period appeared to be the best detector of individuals with occupational asthma, as confirmed by inhalation challenge with spiramycin.

Adult↗
PubMed1988

Nonspecific bronchial hyperresponsiveness to inhaled histamine and hyperventilation of cold dry air in subjects with respiratory symptoms of uncertain etiology.

Fifty adult subjects referred to a respiratory function laboratory of a tertiary care hospital for respiratory symptoms of uncertain etiology were investigated prospectively by means of a questionnaire, isocapnic inhalation of dry cold air (-20 degrees C), histamine inhalation tests, monitoring of peak expiratory flow rates, total eosinophil counts, and total IgE. Wheezing, tightness in the chest, dyspnea, and cough were reported by 35, 23, 41, and 30 subjects, respectively. FEV1 values less than 80% pred were found in only 2 subjects. Twenty-nine subjects had a PC20 histamine less than or equal to 16 mg/ml. Twenty, 15, and 10% falls in FEV1 were found in 10, 18, and 26 subjects, respectively, using hyperventilation of cold air. Significant eosinophilia and increased total IgE levels were seen in 5 and 18 subjects, respectively. Eight subjects had daily changes in PEFR greater than 20% on at least 1 day of monitoring. There was no significant association between specific responses to the respiratory questionnaire or the presence of rhinitis on the one hand and bronchial responsiveness to histamine and cold air on the other hand. The 10 subjects who demonstrated a greater than 20% change in FEV1 after cold air inhalation also had a PC20 less than 16 mg/ml, and 5 of them reacted at a concentration less than or equal to 2 mg/ml. Two subjects who had a PC20 less than or equal to 2 mg/ml demonstrated a less than 20% change in FEV1 after inhaling cold air. There was no association between the increase in total eosinophils or IgE and bronchial hyperresponsiveness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗