TABLE 1.
MP production by murine neutrophils exposed to pressure
MPs were counted in suspensions of neutrophils after exposures to 690 kPa of hydrostatic pressure (Hydro. Press.; cells placed in closed syringes and pressurized with no gas phase), helium, N2, or argon for 30 min or for 4 h. The upper portion of the table shows production rates for suspensions studied at time intervals up to 4 h after a 30-min exposure to pressure, and the lower portion of the table shows MPs/neutrophil in suspensions left at pressure continuously for 4 h and fixed immediately on decompression. Cell viability was assessed as trypan blue exclusion in suspensions at 4 h after the start of the exposure periods (no significant differences among samples). Data are mean ± S.E.; n = sample numbers (in parentheses).
| Exposure conditions | MP count | Viability at 4 h |
|---|---|---|
| % | ||
| 30 min air (24) | 0.3 × 10−3 ± 0.2 × 10−3/PMN/h | 85.3 ± 1.9 |
| 30 min Hydro. Press. (5) | 0.2 × 10−3 ± 0.3 × 10−3/PMN/h | 88.3 ± 2.0 |
| 30 min helium (5) | 1.01 ± 0.12/PMN/ha | 88.0 ± 0.6 |
| 30 min N2 (8) | 3.84 ± 0.21/PMN/ha,b | 85.8 ± 1.7 |
| 30 min argon (5) | 3.47 ± 0.22/PMN/ha,b | 82.7 ± 0.7 |
| 4 h air (8) | 0.0011 ± 0.0007/PMN at 4 h | 85.3 ± 1.9 |
| 4 h Hydro. Press (5) | 0.0008 ± 0.002/PMN at 4 h | 86.7 ± 1.9 |
| 4 h helium (4) | 3.9 ± 0.3/PMN at 4 ha | 86.8 ± 2.0 |
| 4 h N2 (8) | 15.3 ± 0.9/PMN at 4 ha,b | 85.7 ± 1.8 |
| 4 h argon (4) | 15.2 ± 0.9/PMN at 4 ha,b | 82.5 ± 1.6 |
a p < 0.05 versus air sample based on ANOVA.
b p < 0.05 versus helium based on ANOVA.