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D Gautrin

Publications and source records attributed to D Gautrin.

At least 37 records · Page 2Linked to original sources
PubMed1999

Longitudinal assessment of airway caliber and responsiveness in workers exposed to chlorine.

This longitudinal study (1992-1994) was performed to determine the relation between accidental chlorine exposure and changes in lung function and airway responsiveness in 239 workers in a metal production plant. These workers had taken part in a cross-sectional survey in 1992. In both the initial and the follow-up surveys, history of exposure to chlorine ("puffs"), accidental chlorine inhalation reported to the first-aid unit (gassing incidents), and of chronic symptoms were documented; spirometry and methacholine challenge tests were performed. At follow-up, 211 workers (88.3%) were seen. In workers with 20 pack-years or more of cigarette smoking, the fall in FEV(1) was associated with having had a gassing incident during the follow-up period; the fall in FEV(1)/FVC (%) was predicted by the number of puffs causing mild symptoms between the two assessments. An increase in airway responsiveness (PC(20) decrease > 1.5-fold) was present in 19 workers; it was associated with accidents reported to the first-aid unit during the previous 2 yr (OR: 5.9, 95% CI: 1.1 to 32.3). These findings suggest: (1) an effect on airway function related to the estimated number of puffs with mild symptoms and gassing incidents, mostly among smokers; (2) a detectable increase in airway responsiveness associated with gassing incidents.

Accidents, Occupational↗
PubMed1999

Airway hyperresponsiveness and symptoms of asthma in a six-year follow-up study of childhood asthma.

BACKGROUND AND AIM: In an inception cohort study of 457 asthmatic children diagnosed at the age of 3 to 4 years, airway hyperresponsiveness (AHR) was assessed 6 years after first diagnosis in a subgroup of 84 children. Our objective was to associate the level of AHR with the symptomatic asthma status at follow-up. METHODS: Information on respiratory symptoms and medication use for the previous 6 years was obtained. Children with reported wheezing episodes during the previous year (n = 169) or for > or = 2 years at any time during the follow-up period (n = 85) were eligible for the challenge test. RESULTS: Among the 254 eligible children, 166 were randomly selected. The parents of 88 of them consented to have their child participate. At the time of assessment of AHR, 19 children (22%) were asymptomatic and 24 others (29%) had symptoms but did not use any medication. Forty-one children (49%) were symptomatic and required medication, including antiinflammatory preparations in 26 instances (31%). All but two children had significant AHR. There was no significant association between the level of AHR and graded symptomatic and medication score. Twenty-four of the 70 children (34%) with greatly enhanced AHR used no medication. CONCLUSIONS: This study shows that (1) almost all children first diagnosed with asthma 6 years ago and with persisting but not necessarily current symptoms of asthma have increased AHR, which satisfies a proposed epidemiologic definition of asthma; (2) AHR was present in 95% of the 20 currently asymptomatic children; and (3) one third of children with greatly enhanced AHR did not use any treatment.

Asthma↗
PubMed1998

Changes in IgE-mediated allergy to ubiquitous inhalants after removal from or diminution of exposure to the agent causing occupational asthma.

BACKGROUND: One possibility, among others, for explaining the persistence of asthma symptoms in occupational asthma (OA) after the cessation of exposure to the causal agents may be that subjects become sensitized to ubiquitous inhalants. OBJECTIVE: The aim of this study was to evaluate the development or increase of IgE-mediated sensitization to ubiquitous allergens, both to high- and low-molecular-weight agents, in 100 subjects with OA after cessation of exposure. METHODS: Subjects were evaluated on a first visit, at the time of diagnosis of OA, coinciding with the cessation or diminution of exposure to the causal agent, and on a second visit, 5.8+/-3.3 years afterwards. At each visit, a history of ocular, nasal and asthmatic symptoms related to exposure to common allergens was obtained together with spirometry and assessment of bronchial responsiveness to methacholine. We analysed total IgE and specific IgE to Dermatophagoides farinae, D. pteronyssinus, birch, ragweed and timothy grass pollens, cat and dog danders, and Alternaria, using enzyme allergosorbent test (EAST) from blood samples taken on each visit. RESULTS: Total IgE levels showed a tendency to diminish. No changes were found in the number of positive EAST (presence of detectable levels of specific IgE) or in the levels of specific IgE. Although significantly more symptoms of rhinoconjunctivitis and asthma in contact with house dust (P < 0.05) and pets (P < 0.01) were reported on the second visit than on the first, no significant changes in the frequency of symptomatic sensitized subjects were found. CONCLUSION: Subjects with OA are unlikely to develop IgE-dependent sensitization to common inhalants after removal from exposure to occupational agents.

Adult↗
PubMed1998

Changes in airway function and bronchial responsiveness after acute occupational exposure to chlorine leading to treatment in a first aid unit.

OBJECTIVES: To describe the baseline characteristics and the time course of changes in lung function in workers accidentally inhaling high concentrations of chlorine in a prospective study. METHODS: Baseline spirometry and methacholine challenge test were performed in a cohort of 278 workers at risk of accidental inhalation of chlorine. Workers in whom accidental inhalation led to intervention in a first aid unit were reassessed five to 25 days after the accident and serially thereafter when there where notable changes. RESULTS: During a four year follow up period, 13 workers were seen at the first aid unit after a symptomatic accidental inhalation. Three of them experienced notable functional changes: one worker experienced a 10% fall in forced expiratory volume in one second (FEV1), and the other two had a notable fall in the concentration of methacholine that caused a 20% fall in FEV1 (PC20). Two workers were smokers and one had a personal history of atopy. Baseline assessment was within the normal range in these three workers. Recovery was complete three months after the accidental inhalation. CONCLUSION: Transient but notable decreases in airway function or increases in bronchial responsiveness can occur after an accidental inhalation of high concentrations of chlorine in workers at risk.

Adult↗
PubMed1998

Follow-up of occupational asthma after removal from or diminution of exposure to the responsible agent: relevance of the length of the interval from cessation of exposure.

STUDY OBJECTIVE: We set the hypothesis that follow-up surveys of occupational asthma (OA) could now show better improvement in the asthmatic condition because of a more prolonged interval since removal from exposure than in previously reported studies. PATIENTS/METHODS: Ninety-nine subjects with OA were assessed and were separated into two groups according to the duration of cessation of exposure: (1) group removed for > or = 5 years: 48 subjects studied 8.9+/-2.2 years after cessation of exposure; (2) group removed for <5 years: 51 subjects with OA, comparable in terms of history and functional results at time of diagnosis, with a time lapse from last exposure of 3.1+/-1.2 years. On the follow-up visit, questionnaires including information on the current and previous use of inhaled steroids, spirometry, and methacholine tests were administered and results were compared with those obtained at the time of diagnosis. RESULTS: At the follow-up visit, no significant changes in spirometry were observed in the two groups. However, a significant improvement in provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) from a mean value of 1.5 to 3.7 mg/mL was documented (p<0.001). The proportion of subjects having normal PC20 at the follow-up visit was significantly higher in the group removed from exposure for >5 years than in the group removed for < or = 5 years (16/33 vs 8/42; p=0.01). Stepwise logistic regression showed that follow-up PC20 could be predicted from baseline PC20 (p<0.001, odds ratio [OR]=4.1, 95% confidence interval [CI]=1.8 to 9.1), duration of exposure (p=0.04, OR=0.9, 95% CI=0.8 to 1.0), the interval since removal from exposure (p=0.002, OR=1.7, 95% CI=1.2 to 2.5), and the type of agent; subjects with OA due to high-molecular-weight agent showed a less favorable outcome (p=0.04, OR=0.2, 95% CI=0.03 to 1.0). Current and past treatments with inhaled steroids were not significant predictors. CONCLUSION: Results obtained in the group of this study removed for >5 years show better prognostic figures than those reported in most previous studies. Comparison with the group removed for a shorter interval and the stepwise logistic regression analysis suggest that the longer duration of the interval from cessation of exposure appears to be a factor determining this difference.

Adult↗
PubMed1997

Specific IgE-dependent sensitization, atopy, and bronchial hyperresponsiveness in apprentices starting exposure to protein-derived agents.

Atopy, specific IgE sensitization, and bronchial hyperresponsiveness (BHR) were examined in a cohort of 769 apprentices starting career programs in animal health or veterinary medicine (Group 1), pastry making (Group 2), and dental hygiene (Group 3). The hypothesis were that: (1) a proportion of subjects can be "sensitized" although no significant specific occupational exposure has occurred; and (2) there is a relationship between baseline specific sensitization to work-related antigens and host characteristics. Skin tests were administered using 11 common inhalants and specific allergens, including six laboratory animal extracts, three cereal antigens, alpha-amylase, and latex. Methacholine challenge tests were performed. The prevalence of atopy was 54.4% in Group 1, 58.1% in Group 2, and 52.5% in Group 3. Skin reactivity to work-specific proteins was as follows: laboratory animal proteins, 13.8% in Group 1, 14.0% in Group 2, and 15.6% in Group 3. No subject was sensitized to alpha-amylase, whereas 1.2% in Group 1, 5% in Group 2, and 4.1% in Group 3 were sensitized to flour. Five subjects reacted to latex. BHR (PC20 < or = 8 mg/ml) was present in 17.6%, 21.2%, and 14.8% of subjects in Groups 1, 2, and 3, respectively. Specific sensitization was associated with positive skin reactions to common allergens, work-related symptoms, and BHR. These results suggest that students starting career programs with exposure to high-molecular-weight allergens have a low but substantial frequency of specific sensitization to work-related allergens that is related to atopy and BHR.

Adult↗
PubMed1996

Nonsensitizing causes of occupational asthma.

Irritant-induced asthma and RADS are related conditions that need further study focusing on the following questions: (1) Are there differences between the pathologic and functional features that follow single or multiple exposures to an irritant material? (2) What is the time course of the changes? (3) What are the physiologic correlates in terms of onset of airway hyperresponsiveness? (4) What are the risk markers (besides exposure)? (5) Are there means of modulating the reaction by using anti-inflammatory preparations? Developing an animal model of irritant-induced asthma and conducting prospective epidemiologic surveys in high-risk workers may be most effective routes to provide satisfactory answers to these questions. Further examination of the physiopathology of such conditions as byssinosis, grain-dust-induced respiratory disease, and aluminum potroom asthma as well as of the differences from and similarities to OA is also warranted.

Asthma↗
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

Cross-sectional assessment of workers with repeated exposure to chlorine over a three year period.

Airflow obstruction has been described in workers who experienced symptoms after acute exposure to chlorine. Persistent bronchial hyperresponsiveness has also been assessed, but mainly in case studies. In this cross-sectional study, we have assessed the relationship between inhalational accidents ("puffs") involving chlorine and persistent symptoms as well as hyperresponsiveness in 239 out of 255 at-risk workers (94%). No relationship was found between persistent symptoms and the exposure variables studied. Forced vital capacity (FVC) was higher in subjects who had had no symptoms after a "puff", compared with those who had experienced mild symptoms. Forced expiratory volume in one second (FEV1) and FVC were significantly lower in subjects who experienced more than 10 puffs with mild symptoms than in subjects who reported no symptomatic puff. The presence of bronchial hyperresponsiveness was not related to exposure, but the methacholine dose-response slope showed a tendency to increased bronchial responsiveness with increased exposure. A significant difference was shown in subjects who experienced more than 10 puffs with mild symptoms. In this group of workers, repeated exposure to chlorine with acute respiratory symptoms was associated with a slight but significant reduction in expiratory flow rates, together with an increase in bronchial responsiveness, without long-term symptoms.

Adolescent↗
PubMed1995

[Chronic hyperventilation syndrome. The role of respiratory re-training].

This study compares three non-pharmacological approaches to the chronic hyperventilation syndrome (CHS). Eighteen subjects were evaluated at the start of the study then one and 6 months after having received in a random fashion one of the following treatments: group I (teaching approach of one hour on the respiratory physiology of the CHS and on breathing techniques; n = 5); group II (same approach as in group I with breathing retraining of 8 sessions; n = 8); group III (same as group II with the addition of a modified Jacobson's progressive relaxation; n = 5). Whereas all three groups had a similar symptomatic score at the beginning of the study (although subjects of group III had in general higher scores and were symptomatic for a longer period), our results show that all subjects improved after 4 weeks, those in group II showing the greatest improvement (p < 0.05). This confirms the relevance of applied and repeated pedagogy in approaching subjects with the CHS.

Adolescent↗
PubMed1994

Is reactive airways dysfunction syndrome a variant of occupational asthma?

BACKGROUND: Reactive airways dysfunction syndrome (RADS) or irritant-induced asthma is a syndrome that leaves subjects with asthma-like symptoms after one or more exposures to a high concentration of an irritant substance. The degree of reversibility of airway obstruction in subjects with RADS is nevertheless unknown, as is the degree of associated lesions at the airway level. METHODS: We compared the acute reversibility of forced expiratory volume in 1 second (FEV1) after inhalation of albuterol (200 micrograms) in 15 subjects with RADS (12 cases caused by chlorine inhalation) with that of 30 subjects with occupational asthma (OA) caused by various agents. They were paired according to baseline airway obstruction (61% and 63% of predicted value in the RADS and OA groups), requirement for medication (bronchodilator only--7 of 15 subjects with RADS and 14 of 30 subjects with OA--as compared with bronchodilator + inhaled steroids in 8 of 15 subjects with RADS and 16 of 30 subjects with OA, respectively), and interval since removal from exposure (means of 30 and 24 months in the RADS and OA groups). In addition, five nonsmokers with RADS who had not received inhaled steroids underwent bronchoscopy with lavage and bronchial biopsies less than 2 years after the exposure. RESULTS: The percentage increase in FEV1 over baseline after inhalation of albuterol was 10% +/- 9% in the RADS group and 19% +/- 16% in the OA group (p = 0.005). Only 2 of 15 subjects (13%) with RADS and 12 of 30 subjects (40%) with OA showed an improvement in FEV1 of 20% or greater after inhalation of albuterol. Bronchoalveolar lavage showed an increased number of cells with a predominance of lymphocytes, and biopsy specimens showed increased basement membrane thickness in the five subjects with RADS who underwent bronchoscopy. CONCLUSION: Subjects with RADS are generally left with less airway reversibility than those with OA. We suggest that this difference is secondary to distinct pathologic changes.

Adult↗
PubMed1994

Allergenic exposure, IgE-mediated sensitization, and related symptoms in lawn cutters.

AIMS: The aims of the study conducted on lawn cutters were: (1) to evaluate exposure to pollens and molds; and (2) to assess the prevalence rate of IgE sensitization and symptoms in relation to exposure to pollens and molds. METHODS: Environmental assessment was done with the use of personal samplers on eight workers. Our population consisted of 181 municipal park workers, including 128 lawn cutters and 67 control subjects (blue-collar workers in the hospital). A questionnaire was administered, as well as skin prick tests with seven common inhalants including pollens and eight grass molds. The main outcome variables were grass or mold sensitization (at least one of eight molds) and work-related rhinitis, conjunctivitis, and rhinoconjunctivitis. Atopy and exposure to park-related allergens, as well as sensitization to grass pollens, were considered as explanatory factors. Smoking was taken into consideration as a covariant. Both presence and duration of occupational exposure to park-related allergens were considered as parameters of exposure. Duration of exposure (months x years of exposure as lawn cutters) was used as a continuous or as a categorical variable. RESULTS: Environmental monitoring showed that the concentration of pollens and molds decreased in magnitude from samples collected close to lawn cutters faces, short distance away in parks, and in the general environment. There was no difference in the prevalence rates for atopy between lawn cutters (32%) and control subjects (37%). Sensitization rates to grass pollen were also similar in lawn cutters (18%) and in control subjects (22%). However, there was a tendency for prevalence rates of sensitization to molds to be greater among lawn cutters (12% to Alternaria) compared with control subjects (5%). In the logistic model atopy was significantly related to grass sensitization (odds ratio [OR] = 7.2), mold sensitization (OR = 9.3), and sensitization to Alternaria (OR = 5.8). Grass sensitization was a significant risk factor for park-related rhinitis (OR = 5.8), conjunctivitis (OR = 5.0), and rhinoconjunctivitis (OR = 9.4). Exposure for 12 years or more was associated with rhinoconjunctivitis with an OR of 4.1 (95% confidence interval, 1.0-16.7). Smoking was not significantly related to any outcome. CONCLUSION: We conclude that among lawn cutters exposure to pollens and molds is higher than in the general population, atopy is the main determinant of sensitization to these aeroallergens, and sensitization and, to a much lesser extent, exposure to grass are determinants of symptoms.

Adult↗
PubMed1994

Comparison between peak expiratory flow rates (PEFR) and FEV1 in the monitoring of asthmatic subjects at an outpatient clinic.

Peak expiratory flow rate (PEFR) monitoring is often used alone in evaluating bronchial caliber and the response to a bronchodilator in the assessment of asthmatic subjects. A 15% change in airway caliber has been proposed as the criteria for modifying treatment. Our aim was to determine if changes in PEFR from one visit to the next can adequately evaluate changes in airway caliber as assessed by FEV1, which is considered the gold standard, and to identify the characteristics of subjects whose evaluations were inadequate. This was a retrospective study of 197 asthmatic subjects seen regularly at an outpatient clinic for whom FEV1 and PEFR assessments, prebronchodilator and postbronchodilator, were available for two visits. There was a high correlation between PEFR and FEV1 (in absolute value or percent predicted) (r = 0.83 and r = 0.75). However, 24 of 56 (43%) of those who had a change in FEV1 of 15% or more between two visits (mean change [%] +/- SD, range [best-lowest/best] = 20.9 +/- 5.1%, 15 to 36%) showed changes in PEFR of less than 15% (6.7 +/- 6.5%, 8.0 to 13.9%). On the other hand, 14 of 42 (33%) subjects with changes in FEV1 of less than 15% (9.8 +/- 3.2%, 1.1 to 13.8%) had changes in PEFR of 15% or more (22.2 +/- 10.9%, 16 to 35%). This discrepancy was not related to differences in baseline FEV1, control status, or the relationship between changes in FEV1 and PEFR in response to a bronchodilator. In conclusion, assessment of airway caliber through PEFR monitoring may not be valid in some asthmatic subjects and can often lead to underestimation or overestimation of changes in FEV1. None of the explanations considered made it possible to identify these subjects.

Adolescent↗
PubMed1990

Neurotoxic effects of styrene: further evidence.

The relation of exposure to styrene to measures of nervous system function was investigated in 70 men working in four factories in the Montreal area of Quebec. Mild sensory nerve conduction deficits were found, the proportion with such deficits rising from 23% in those exposed to less than 50 ppm to 71% in those exposed to more than 100 ppm. Reaction time was slower for those with a larger body burden, as indicated by area under the excretion curve, and for those who failed to clear the metabolite during the weekend. No slowing in conduction time was found among a small group of five men exposed to more than 100 ppm for less than four weeks. There was some evidence that both central and peripheral slowing recovered when workers were removed from exposure. Uptake, storage, or elimination of styrene was influenced by the physical demands of the work, skinfold thickness, cumulative exposure, and alcohol consumption. Nevertheless, only the wearing of a mask and current consumption of alcohol were associated with a lower risk of sensory conduction deficit. While there was no clear indication that neurotoxic effects were related to individual differences in the capacity to metabolise high concentrations of styrene, measurement of urinary metabolites may be helpful in identifying those at highest risk.

Adolescent↗
PubMed1990

Canadian projections of cases suffering from Alzheimer's disease and senile dementia of Alzheimer type over the period 1986-2031.

Alzheimer's disease (AD) is characterized by irreversible changes in cognitive and intellectual functions, accompanied by progressive memory loss, and described by neurochemical and neuropathological impairments. The classic term Alzheimer's disease applies to presenile dementia, while all of the syndromes that share the distinctive signs of AD are known as senile dementia of the Alzheimer type (SDAT). In Canada, as in several other industrialized countries, we are seeing a rapid growth of the elderly population. The renewed interest in AD and SDAT is partly attributable to the view that the increasing percentage of sufferers will have a significant socioeconomic impact. Few attempts have been made to project the number of cases of SDAT in Canada. In assessing the prevalence of SDAT in an over 65 population, a rate of 2.5% (or 3%) is commonly applied. This rate corresponds to one half the estimated prevalence rate for all severe types of dementia, using an average of the rates arrived at by some ten studies. The authors dispute this approach: i. the assumption that 50% of dementia cases will be AD is not verified for all populations; ii. the use of a single prevalence rate for everyone over age 65 is rather uninformative; and iii. the combining of results from various sources is questionable given the possible lack of consistency in the following respects: diagnostic criteria, methods of investigation, effort made to recruit cases, and representativeness of the groups studied. In this article, prevalence rates by age group have been inferred based on two Finnish studies conducted in the 1980s on the prevalence of AD in the general population.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Alzheimer's disease: environmental factors and etiologic hypotheses.

A review of published reports on conventional and unconventional viruses, aluminum, neurotoxic metals and trace elements, neurotoxins of biological origin and immune systems, suggest that environmental factors, possibly multiple ones, play a significant role in the etiology of Alzheimer's disease. A complex interaction between genetic predisposition to this illness, natural aging processes, environmental factors over a life-time exposure and pathological alterations of the host immune system is proposed.

Alzheimer Disease↗
PubMed1989

Ascertainment of informative Alzheimer disease families from the IMAGE Project registry for genetic linkage analysis studies.

Genetic linkage analysis requires the identification and documentation of large families with many affected members present, preferably in more than one generation. The IMAGE Project has been establishing a population-based Alzheimer disease (AD) registry in the Saguenay - Lac-Saint-Jean region of the Province of Quebec. The population of this region has a well-documented ancestry, with reliable genealogical records (since 1842) computerized by SOREP. We have recently begun to investigate the pedigrees of selected probands (definite, probable and possible) from the IMAGE registry in order to identify informative pedigrees for genetic linkage analysis. Interviews were carried out with close relatives of the probands (at least one informant per sibship) to identify secondary AD cases. The questionnaires used pertain to the accuracy of genealogical records, to family medical history and to a retrospective diagnosis of AD for people with cognitive deficits. By these means, we have documented a large extended pedigree in which a total of 15 individuals with cognitive deficits were ascertained over three generations. Of these cases, 7 are still living and there is autopsy confirmation in another one. Computer simulations using the program SIMLINK revealed that this is a potentially informative family for linkage analysis. Horizontal extension of the pedigree to second cousins of the proband is now being carried out. This will render the family IMAGE/1 even more informative in genetic linkage analysis studies.

Alzheimer Disease↗