Hypoxia induces fibrin deposition in TM^−/− chimeric mice. (A) Western blot of β-fibrin from 6- to 11-month-old TM chimeras. Mice were paired according to agouti coat coloring and one animal from each pair was maintained under normoxic conditions (lanes 1, 2, and 3) while the other was exposed to hypoxic conditions (lanes 4, 5, and 6). Western blot analysis of urea-insoluble tissue samples was conducted using an MoAb against the amino-terminus of Bβ-fibrin. (B) Western blot of purified β-fibrin showing the standard curve containing: lane 1, 250 ng; lane 2, 150 ng; lane 3, 100 ng; lane 4, 50 ng; and lane 5, 20 ng. (C) Quantitation of cross-linked fibrin from Western blot shown in A. Values are expressed as μg β-fibrin per 100 mg of lung tissue.