Circadian variations of airway response to histamine in asthmatic subjects
Rachiele, A.; Malo, J.L.; Cartier, A.; Pineau, L.; Ghezzo, H.; Martin, R.R.
Bulletin Europeen de Physiopathologie Respiratoire 19(5): 465-469
1983
ISSN/ISBN: 0395-3890 PMID: 6640165 Document Number: 214457
In 15 clinically stable asthmatic 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 08:00, 16:00 and 22:00 h were 0.95, 0.88 and 0.78, respectively. The dispersion of results of PC20 was significantly (P < 0.05) more pronounced at 22:00 h than at 08:00 h. The cosinor analysis which depicts biologic rhythms as sinusoidal curves revealed that 7 subjects had detectable diurnal rhythms with acrophases (time of least excitability) at 09:00, 10:00, 11:08, 15:18, 15:24, 22:12 and 23:06 h. In 5 and 3 of these 7 subjects, respectively, significant rhythms of FEV1 and FEF25-75% were also detected with similar acrophases.