Figure 2

In vivo and in vitro leukotriene levels. Comparisons between the young and older groups were performed with t test analysis or Mann-Whitney rank sum analysis. Statistical significance was defined at p < 0.05. White bars: young subjects; Gray bars: older subjects Mean: - - -(dashed) Median: ----- (solid). 2A and 2B. Sputum was processed and LTB₄ and CysLT levels were measured using the LTB₄ and CysLT competitive EIA kit, respectively (Cayman Chemical, Ann Arbor, MI). Sputolysin (Calbiochem) was added to all assay standards to represent an equivalent amount in the diluted sputum samples and run in duplicate. Standard curves for LTB₄ and CysLT were performed both with and without Sputolysin to ensure an equivalent slope was obtained. Young: n = 11 (One young subject had > 80% epithelial cells in the sputum and was not included in the biochemical analysis.); Older: n = 6. 2C and 2D. Peripheral blood neutrophils and eosinophils were isolated and stimulated with calcium ionophore (A23187) for 60 min at 37°C. LTB₄ and LTC₄ were measured by competitive EIA kit (Cayman Chemical, Ann Arbor, MI). Young: n = 12; Older: n = 6