A single measure of FEV1 is associated with risk of asthma attacks in long-term follow-up

BACKGROUND: Clinical practice guidelines for asthma care emphasize the use of objective measures of asthma severity, and yet little data exist on the relationship between FEV(1) and asthma outcomes over long-term follow-up. METHODS: We explored the association between measures of FEV(1) percentage of predicted (FEV(1)% predicted) and subsequent asthma attacks over 3-year intervals. Subjects were identified from two longitudinal cohort studies conducted in the United States and the Netherlands. Persons were included in the analysis if they reported ever having an attack of wheezing with associated shortness of breath prior to or during the follow-up period. RESULTS: Over the course of longitudinal follow-up at 3-year intervals, 195 subjects in the Netherlands cohort contributed 510 observations, and 698 subjects in the US cohort contributed 1,268 observations (for each observation, the report of an attack since their last visit was paired with the subject's FEV(1) recorded 3 years prior). Overall, subjects in the Netherlands cohort experienced 114 attacks (22% of the observations) and subjects in the US cohort had 517 attacks (40.6% of the observations). FEV(1)% predicted was significantly associated with risk of an asthma attack over the 3 years following its measurement. After adjusting for current smoking and gender, FEV1% predicted remained an independent predictor of subsequent asthma attacks. CONCLUSIONS: These findings support the use of spirometry as an objective measure of asthma severity and risk of adverse outcomes.     

Immune Lysis of Liposomes and Erythrocyte Ghosts Loaded with Spin Label

It is shown that the paramagnetic resonance of spin labels offers a convenient technique for monitoring the complement-mediated immune lysis of erythrocyte ghosts, and sensitized phospholipid liposomes. The ghosts or liposomes are loaded with a concentrated solution of a water-soluble, membrane-impermeable spin label, so that there is a strong exchange broadening of the paramagnetic resonance signal due to labels enclosed within the liposomes or ghosts. Complement-mediated lysis releases the labels into a dilute solution, where a relatively sharp and intense paramagnetic resonance signal is detected.AN UNANTICIPATED RESULT IS ALSO REPORTED: this is the augmentation of release of spin label from loaded ghosts sensitized with egg albumin, in the presence of antibody against egg albumin, complement, and egg albumin in solution, over and above the release in the absence of egg albumin in solution. Comparison with complement fixation suggests that the augmentation of lysis is effected by crosslinking of immune complexes with the cell membrane.