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Biomedical subjects

Paul Bégin

Publications and source records attributed to Paul Bégin.

5 recordsLinked to original sources
PubMed2005

Clinical features and airway inflammation in mild asthma versus asymptomatic airway hyperresponsiveness.

RATIONALE: We still do not know why some subjects with airway hyperresponsiveness (AHR) experience no respiratory symptoms. OBJECTIVES: Our aim was to compare pulmonary function, perception of bronchoconstriction, and airway inflammation in atopic subjects with mild recently diagnosed (<5 years, n=30) or longer-standing (5 years or more, n=30) symptomatic asthma in comparison with atopic subjects with asymptomatic AHR (n=27). METHODS: All subjects had measurements of expiratory flows, PC(20) methacholine, perception of breathlessness and induced sputum cell differential, eosinophil cationic protein and alpha(2)-macroglobulin levels. RESULTS: Compared with the other groups, PC(20) was significantly lower in longer-standing asthma and perception score for breathlessness at 20% fall in FEV(1) was lower in asymptomatic subjects. Markers of airway inflammation were similar in all groups. There were no significant correlations between sputum eosinophils, alpha(2)-macroglobulin and/or eosinophil cationic protein levels and FEV(1), FVC or PC(20) in either group. CONCLUSION: Subjects with mild asthma or asymptomatic AHR are similar in regard to induced sputum markers of airway inflammation. Although perception of bronchoconstriction was slightly lower in asymptomatic subjects, additional factors are probably involved to explain why they report no respiratory symptoms. Further studies are needed to determine why these last are asymptomatic.

Adolescent↗
PubMed2005

Effect of increased diaphragm activation on diaphragm power spectrum center frequency.

Increased transdiaphragmatic pressure, reduced muscle blood flow, and increased duty cycle have all been associated with a reduction in the center frequency (CFdi) of the diaphragm's electrical activity (EAdi). However, the specific influence of diaphragm activation on CFdi is unknown. We evaluated whether increased diaphragm activation would result in a greater decline in the CFdi when pressure-time product (PTPdi) was kept constant. Five healthy subjects performed periods of intermittent quasi-static diaphragmatic contractions with a fixed duty cycle. In separate runs, subjects targeted transdiaphragmatic pressures (Pdi) by performing end-inspiratory holds with the glottis open and expulsive maneuvers at end-expiratory lung volume (EELV). Diaphragm activation and pressures were measured with an electrode array and balloons mounted on an esophago-gastric catheter, respectively. The EAdi, which was 25+/-8%(S.D.) of maximum at EELV, increased to 61+/-8% (P<0.001) when an identical Pdi (averaging 31+/-13 cmH2O) was generated at a higher lung volume (77% of inspiratory capacity). The latter was associated with a 17% greater decline in CFdi (P=0.012). In order to reproduce at EELV, the decrease in CFdi observed at the increased lung volume, a two-fold increase in PTPdi was required. We conclude that CFdi responds specifically to increased diaphragm activation when pressure-time product remains constant.

Action Potentials↗
PubMed2004

Sleep complaints in patients with myotonic dystrophy.

The aim of this study was to document the clinical picture of excessive daytime sleepiness (EDS) and of other sleep disturbances, and to study the relationship of daytime sleepiness to anthropometric data, muscular impairment, and CTG trinucleotide repeat expansion in myotonic dystrophy type 1 (DM1). A total of 157 DM1 patients were surveyed using a modified version of the Sleep Questionnaire and Assessment of Wakefulness. Other measurements included muscular impairment rating and the size of the trinucleotide repeat. Factor analysis and reliability estimates were used to produce a daytime sleepiness scale with five items of the questionnaire. Thirty-eight healthy family members were studied as control subjects. It was found that EDS was present in 33.1% of DM1 patients. Severity of daytime sleepiness correlated with the degree of muscular impairment but not with age, gender, body mass index, age at onset of symptoms, duration of illness, and CTG repeat. DM1 patients reported a longer sleep period, a less restorative sleep, and more difficulty falling asleep, being alert in the morning and staying awake after meals than controls, but a similar incidence of narcolepsy auxiliary symptoms. Compared with DM1 patients without EDS, those with EDS reported greater hypnagogic hallucinations, and greater pain associated with nocturnal awakenings and in their legs upon morning awakenings. In sum, both DM1 patients with and without EDS exhibit characteristics of sleep duration and sleepiness comparable with those found in idiopathic hypersomnia. The severity of daytime sleepiness is weakly related to the extent of muscular impairment but not to CTG repeat.

Adult↗
PubMed2004

Exclusion spirometry: an initiative to increase lung function assessment in primary care.

Ongoing spirometry quality standards are difficult to bring into the daily routine of general practice. As a result, spirometry is rarely performed by primary care physicians. A new approach is proposed: exclusion spirometry. Acceptable and reproducible results are sought. However, the goal of the test is to try to reach values within normal limits, even if results do not reach quality standards. Normal results would be sufficient to exclude respiratory impairment, except in asthma. Abnormal results would require further testing in a diagnostic spirometry laboratory. The aim of the initiative is to enhance the compliance of general practitioners in using spirometers for screening.

Humans↗