“…Lungs from saline-washed mice were dissected, frozen immediately in liquid nitrogen, and stored at Ϫ 80 Њ C. After homogenization in guanidinium/thiocyanate, total RNA was isolated by cesium chloride centrifugation as described previously (13). uPA, tPA, PAI-1, PAI-2, ␣ 2-antiplasmin ( ␣ 2-AP), and protease-nexin I (PN-I) probes were prepared as described (14)(15)(16)(17)(18) and transcribed in vitro using ␣ 32 P-labeled UTP (specific activity 400 Ci/mmol; Amersham International, Buckinghamshire, United Kingdom). RNase protection assays were performed as described (19).…”