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Biomedical subjects

A Cartier

Publications and source records attributed to A Cartier.

At least 181 records · Page 10Linked to original sources
PubMed1983

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. After being exposed for 5 min, the subject developed general malaise, cough, fever, and leukocytosis, together with a mixed restrictive and obstructive breathing defect. We demonstrated a subsequent increase in airway hyperexcitability, which lasted for 2 mo. The subject was also challenged with diphenylmethane diisocyanate (MDI) for 15 min. A late obstructive reaction was documented. Increased levels of specific IgG antibodies against HDI-human serum albumin (HSA) and MDI-HSA were demonstrated.

Alveolitis, Extrinsic Allergic↗
PubMed1983

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 18.6 +/- 7.9 (SD) and 19.1 +/- 10.3% of initial value after histamine and methacholine, respectively (NS). Whereas the peak action occurred in a similar interval (1-4 min), the mean duration of the subsequent plateau, defined as values of sGL within 20% of the maximum fall was 16.8 +/- 9.8 min for histamine and 74.6 +/- 53.7 min for methacholine (P less than 0.01). The recovery phase from the end of the plateau to base line lasted 25.5 +/- 14.4 min for histamine and 56.7 +/- 38.3 min for methacholine (P less than 0.01). The duration of plateau and recovery phases were not linked with base-line sGL, maximum fall in sGL, or C6. We conclude that for the same induced bronchoconstriction methacholine has a more prolonged action than histamine.

Adolescent↗
PubMed1983

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. Eight subjects had PC20 values less than 16 mg/ml. In these subjects, the test had a good reproducibility (r = 0.92) when we repeated it, and serial measurements of peak expiratory flow rates did not suggest asthma. The fact that PC6 was related, although loosely, to baseline FEV, FEV/FVC, and forced expiratory flow during the middle half of the FVC (FEF) and that 4 of the 8 subjects with PC20 values less than 16 mg/ml had lower values of FEF might suggest that responsiveness to methacholine is partially linked with baseline airway caliber.

Adult↗
PubMed1982

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. Experimental inhalation challenges with NiSO4 at the same concentration of 10 mg/ml for 60 sec produced a bronchial obstruction typical of an early asthmatic response. A control asthmatic subject with a similar level of sensitivity to histamine failed to react after the same inhalation of NiSO4, which suggests a specific rather than irritant mechanism for the reaction. the patient had evidence of IgE antibody to a NiSO4-human serum albumin antigen. His serum selectively bound 63 Ni, and the test was selectively blocked by nonlabeled nickel sulfate. These results, evaluated together, suggest the development of occupational asthma caused by allergy to NiSO4 in this patient.

Adult↗
PubMed1981

Effects of oxatomide compared with chlorpheniramine in allergic rhinoconjunctivitis.

Oxatomide is an H1 receptor antagonist, which also inhibits antigen-induced mediator release from sensitized mast cells and basophils. The effects of ingested oxatomide (30 mg/capsule) were compared with those of chlorpheniramine (5 mg/capsule) in a double-blind non-crossover study in two groups of twenty-five subjects with ragweed pollen-induced hay fever during the pollen season. Oxatomide or chlorpheniramine was started when symptoms became troublesome and was used in a dose of two to four capsules daily according to severity. Other medications were added, in a standardized way, if hay fever symptoms were not controlled by the test capsules. Forty-one subjects completed the study; nineteen received oxatomide and twenty-two chlorpheniramine. Mean symptom scores, number of test capsules and number of doses of additional medication were not significantly different between the two groups. Drowsiness was reported by subjects in both groups but was worse in the chlorpheniramine group (P less than 0.05). We conclude that, in the studied doses, oxatomide is as effective for the treatment of allergic rhinoconjunctivitis as chlorpheniramine and produces less drowsiness.

Adolescent↗
PubMed1980

Asthma caused by occupational exposure to a furan-based binder system.

A 50-yr-old mold maker developed severe asthma a few weeks after commencing work with a furan binder. Asthma recurred within hours of subsequent exposure and was confirmed by measurements every 2 hr of peak flow rate. The molds were prepared by mixing sand with a resin (containing furfuryl alcohol, paraformaldehyde, and xylene) and a catalyst (containing sulfuric acid, phosphoric acid, and butyl alcohol). Occupation-type exposure in the laboratory to the resin mixed with catalyst, and to pure furfuryl alcohol mixed with sulfuric acid or butyl alcohol, provoked late asthmatic responses and heightened nonallergic bronchial responsiveness to inhaled histamine. No changes were produced by the same exposures in an asthmatic volunteer with a similar degree of histamine bronchial responsiveness, or in the worker after exposure to resin alone and catalyst alone. Avoidance of exposure was followed by clearing of symptoms and return of histamine bronchial responsiveness towards normal. The findings identify the occurrence of specific bronchial responsiveness to volatile reaction product(s) of furfuryl alcohol following reaction with sulfuric acid or with butyl alcohol. The incidence of this problem needs investigation, especially since furan-based binder systems are replacing traditional methods.

Albuterol↗
PubMedDate not supplied

Canadian Thoracic Society guidelines for occupational asthma.

OBJECTIVE: To provide broad guidelines and principles to help primary care physicians, occupational physicians, allergists and respirologists with the recognition, diagnosis and management of patients with occupational asthma (OA). OPTIONS: These guidelines are mainly directed towards OA induced by a workplace sensitizing agent. However, irritant-induced asthma and workplace aggravation of underlying asthma are also addressed, and some consideration is given to other differential diagnoses. OUTCOMES: To enable the assessing physician to investigate patients with possible OA appropriately and to provide guidelines for appropriate early referral when specialized investigations are required. To provide an understanding of the appropriate management strategies following objective diagnosis. EVIDENCE: The key diagnostic and management recommendations were based on a critical review of the literature and by specialist consensus meetings. VALUES: Evidence was categorized as follows. Level 1: Evidence from at least one randomized, controlled trial. Level 2: Evidence from at least one well-designed clinical trial without randomization, from cohort or case-control analytical studies, preferably from more than one centre, from multiple time series or from dramatic results in uncontrolled experiments. Level 3: Evidence from the opinions of respected authorities based on clinical experience, descriptive studies or reports of expert committees. Evidence was further subdivided as follows: A. Good evidence to support a recommendation for use; B. Moderate evidence to support a recommendation for use; C. Poor evidence to support a recommendation for or against use; D. Moderate evidence to support a recommendation against use; E. Good evidence to support a recommendation against use. BENEFITS, HARM AND COSTS: The medical and socioeconomic risks and benefits of an incorrect diagnosis of OA and of failure to diagnose true OA were considered in the recommendations. VALIDATION: The document has been reviewed and endorsed by the Canadian Thoracic Society, the Canadian Society of Allergy and Clinical Immunology, and The College of Family Physicians of Canada. CONCLUSIONS: There is good evidence for rapid investigation and objective categorization of presented symptoms into OA, aggravation of underlying asthma, unrelated asthma or other diagnoses. OA should be suspected in all adult onset asthmatics whose asthma begins or worsens while they are working. Investigations should be directed to an objective assessment of asthma and then to an assessment of the work relationship, using a combination of investigations as feasible, which may include immunological tests, pulmonary function assessed during work periods and away from work, and specific challenge tests. Early specialist referral is recommended for diagnosis. Management strategies include general asthma management in addition to measures to avoid further exposure to a relevant workplace sensitizer. Compensation issues and other workers at risk of developing OA also need to be considered when the diagnosis is made.

Adult↗
PubMedDate not supplied

Influence of asthma education on asthma severity, quality of life and environmental control.

BACKGROUND: Several studies have examined the influence of asthma education, focusing mainly on the use of health services. OBJECTIVES: To assess the influence of an asthma education program (AEP) on airway responsiveness, asthma symptoms, patient quality of life (QOL) and environmental control. DESIGN: A prospective, randomized, controlled study with parallel groups. SETTING: Three tertiary care hospitals in Quebec. POPULATION: One hundred and eighty-eight patients with moderate to severe asthma. INTERVENTION: After optimization of asthma treatment with inhaled corticosteroids, patients were randomly assigned to receive either an education program based on self-management (group E) or usual care (control group C). RESULTS: One year after an AEP, there was a significant decrease in the number of days per month without daytime asthma symptoms in group E only (P=0.03). Asthma daily symptom scores decreased significantly in group E in comparison with group C (P=0. 006). QOL scores improved markedly in both groups after treatment optimization during the run-in period (P<0.01). After an AEP, the QOL score increased further in group E patients in comparison with group C patients (P=0.04). The concentration of methacholine that induces a 20% fall in forced expiratory volume in 1 s (PC20) improved significantly in both groups (group E 1.2+/-1.1 to 2.4+/-0. 2, group C 1.5+/-1.2 to 2.4+/-1.3, P<0.01). After one year, 26 of 37 patients from group E sensitized to house dust mites (HDM) adopted the specific measures recommended to reduce their exposure to HDM, while none of the 21 subjects from group C did (P<0.001). Among the patients sensitized to cats or dogs, 15% of patients from group E and 23% of patients in group C no longer had a pet at home at the final visit (P>0.5). CONCLUSIONS: One year after the educational intervention, it was observed that the program had added value over and above that of optimization of medication and regular clinical follow-ups. The education program was highly effective in promoting HDM avoidance measures but minimally effective for removing domestic animals, suggesting that more efficient strategies need to be developed for the latter.

Albuterol↗
PubMedDate not supplied

Can access to spirometry in asthma education centres influence the referral rate by primary physicians for education?

BACKGROUND AND OBJECTIVES: Asthma remains uncontrolled in a large number of asthmatic patients. Recent surveys have shown that a minority of asthmatic patients are referred to asthma educators. The objective of the present study was to assess the influence of increased access to spirometry in asthma education centres (AECs) on the rate of patient referrals to these centres by general practitioners. METHODS: A one-year, prospective, randomized, multicentric, parallel group study was conducted over two consecutive periods of six months each, with added spirometry being offered in the second six-month period to the experimental group. Ten AECs were enrolled in the project. An advertisement describing the AECs' services was sent by mail to a total of 303 general practitioners at the start of each period, inviting them to refer their patients. Measures of the frequency of medical referrals to the AECs were assessed for each period. RESULTS: The group of AECs randomly selected for spirometry in the second six-month period received 48 medical referrals during the first period and 32 during the second one, following proposed spirometry. AECs that had not offered spirometry received five referrals during the first period and seven during the second period. One AEC withdrew a few weeks after the study began and others encountered administrative problems, reducing their ability to provide interventions. CONCLUSIONS: Referral to AECs is not yet integrated into the primary care of asthma and offering more rapid access to spirometry in the AECs does not seem to be a significant incentive for such referrals.

Asthma↗
PubMedDate not supplied

Immunologic aspects of isocyanate asthma: IL-1 beta, IL-3, IL-4, sIL2R, and sICAM-1.

This pilot study investigated serum levels of cytokines and soluble receptors during five positive and five negative isocyanate inhalational challenges. Serum was obtained from 10 individuals with symptoms compatible with isocyanate asthma before isocyanate challenge and the day following their maximal change in pulmonary function after isocyanate challenge. Serum levels of interleukin 1 beta, interleukin 3, interleukin 4, soluble interleukin 2 receptor, and soluble intercellular adhesion molecule 1 were measured and compared. Interleukin 1 beta, interleukin 3, and interleukin 4 were not detected. The mean soluble interleukin 2 receptor and soluble intercellular adhesion molecule 1 levels were not statistically different before and after challenge or between groups. In summary, the cytokines studied are not detectable in peripheral blood during isocyanate inhalation challenge; soluble interleukin 2 receptor and soluble intercellular adhesion molecule 1 are both detectable but do not change significantly after a positive isocyanate challenge.

Administration, Inhalation↗