Figure 2.

Hs3st1 disruption reduces tissue HS^act level but does not alter fibrin accumulation. (a) HS^act content of HS purified from tissues was measured as in vitro anti-Xa activity, where HS containing AT-binding sites catalyzes AT neutralization of factor Xa. Inset shows the activity of tissue HS to catalyze HCII neutralization of T. Activities were calibrated to the USP units of a heparin standard; n = 3 littermates per group. (b) Tissue fibrin accumulation was determined by first preparing urea-insoluble extracts, which selectively enriches for cross-linked fibrin. Fibrin was quantified by Western blots probed with a mAb specific to the cleaved β-chain of fibrin II. Each group contained five young adult mice and five middle-aged mice (∼10 or ∼24 weeks of age, respectively) with no significant effect of age on fibrin accumulation.