Fig. 1.

Microparticles (MPs) in mice following 2-h exposures. Blood-borne MPs were quantified in control mice (air only), and mice were killed immediately after exposure for 2 h to air + 1,000 to 10,000 ppm CO₂. Where shown, mice were injected before exposure with PEG (see materials and methods). Flow cytometric measurements were made to quantify the number of all 0.3 to 1 µm diameter Annexin V-positive particles (top), as well as those expressing proteins specific to certain cells: Ly6G (mature neutrophils), CD41 (platelets), CD14 (predominantly monocytes), and CD31+/CD41-dim (endothelium). Data are means ± SE; n is shown for each sample. *P < 0.05, significantly different from control by ANOVA.