Biomedical subjects

A Cartier

Publications and source records attributed to A Cartier.

185 records · Page 11Linked to original sources

PubMedDate not supplied

Bronchoconstriction due to isocapnic cold air inhalation minimally influences bronchial hyperresponsiveness to methacholine in asthmatic subjects.

The aim of this study was to investigate if bronchial hyperresponsiveness to methacholine could be influenced by a previous bronchoconstriction due to isocapnic inhalation of cold air. Twelve adult asthmatic subjects in a clinical steady state were seen on four different days in a randomized way according to three different sequences. After assessment of spirometry, bronchial responsiveness to inhaled methacholine was determined on each occasion by the provocative concentration causing a fall of 20% in FEV1 (PC20). On two occasions, the methacholine test was preceded by the inhalation of dry cold air which caused significant (greater than 20% change in FEV1) bronchoconstriction. The methacholine test was performed after functional recovery. There was a significant (t = 2.53; p less than 0.05) but minimal (mean changes of 0.65 single two-fold concentration difference) reduction in PC20 after cold air inhalation. It is concluded that cold air-induced bronchoconstriction causes significant but minimal changes in bronchial responsiveness to methacholine in asthmatic subjects.

Asthma↗

PubMedDate not supplied

Monitoring of peak expiratory flow rates in subjects with mild airway hyperexcitability.

Twenty-seven subjects with mild symptoms of bronchial hyperexcitability (cough, dyspnea, wheezing) and low to moderate degree of airway response to histamine monitored their peak expiratory flow rates (PEFR) for a mean +/- SD of 14.4 +/- 4.0 days. This assessment was performed without the use of any medication in 15 subjects, and before and after inhalation of salbutamol in 12 others. 100% and 52% of individuals, respectively, showed baseline FEV1 and maximum mid-expiratory flow rates greater than 80% of predicted. The improvement in FEV1 after salbutamol was less than 20% in every subject and from 10 to 20% in 15%. The mean daily percentage changes in PEFR were greater than the ones observed in normal individuals in only 21% and 50% of the subjects on no medication and on salbutamol, respectively. Diurnal changes in PEFR were significantly negatively correlated with the response to histamine (r = -0.51; p less than 0.01) and baseline FEV1 (r = -0.49; p less than 0.02). We conclude that there are minor fluctuations of PEFR in subjects with mild symptoms and low degree of airway excitability.

Adolescent↗

PubMedDate not supplied

Pulmonary function tests and airway responsiveness to methacholine in chronic bronchiectasis of the adult.

Fifty adults with chronic bronchiectasis (mean duration since diagnosis: 25 +/- 16.4 years), excluding those cases secondary to tuberculosis or hypogammaglobulinemia, were investigated by a questionnaire, a chest radiograph and lung function tests. Of these, 29 with an FEV1 greater than 1.5 1 underwent methacholine inhalation tests. Fourty-three subjects and three subjects respectively showed an obstructive or a mixed obstructive and restrictive defect, only four having normal lung function tests. Sixty-nine percent of subjects tested had a provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) less than 16 mg X ml-1. Subjects with daily sputum production had lower values of FEV1 and FEV1/forced vital capacity (FVC) compared to subjects with less than daily sputum. Subjects with clinical features of bronchial hyperexcitability had significantly lower baseline FEV1, vital capacity, and maximal mid-expiratory flow rate (FEF25-75). Subjects with lower PC20 values had significantly lower baseline FEV1, FEV1/FVC and FEF25-75. Finally, subjects with the greatest extent of radiological abnormalities had lower baseline FEV1, FEV1/FVC and diffusing capacity, and a higher residual volume. We conclude that chronic bronchiectasis is associated with significant changes in lung function tests and increased responsiveness to methacholine in the majority of affected individuals.

Adult↗

PubMedDate not supplied

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. The correlation coefficients of PC20 for the visits at 8, 16 and 22 h were 0.95, 0.88 and 0.78 respectively. The dispersion of results of PC20 was significantly (p less than 0.05) more pronounced at 22 h than at 8 h. The cosinor analysis which depicts biologic rhythms as sinusoidal curves [8] revealed that seven subjects had detectable diurnal rhythms with acrophases (time of least excitability) at 9.8, 10.0, 11.8, 15.3, 15.4, 22.2 and 23.1 h. In five and three of these seven subjects respectively, significant rhythms of FEV1 and FEF25-75% were also detected with similar acrophases.

Adult↗

PubMedDate not supplied

Investigation of occupational asthma.

Occupational asthma is one of the most frequent lung diseases related to work. It is defined as asthma causally and specifically related to exposure to airborne dusts, gases, vapours or fumes in the working environment. Because occupational asthma may cause long-lasting disability, it is important to identify affected workers correctly and to remove them as soon as possible from the sensitizing agent. Although history is the clue to the diagnosis, it is not sensitive nor specific enough, and the diagnosis should be confirmed by objective means. This article reviews the different steps (with their advantages and disadvantages) involved in making the diagnosis: history, confirmation of the diagnosis of asthma, work visit, skin tests and serology, monitoring of peak expiratory flows and nonallergic bronchial responsiveness. The gold standard remains specific inhalation challenges in the laboratory or at work.

Asthma↗