Plasma levels of transforming growth factor beta 1 (TGFβ₁) over time in mice following thermal injury. Anticoagulated whole blood was collected by cardiac puncture and plasma was prepared. Circulating levels of plasma TGFβ₁ were determined at serial times after sham (○) and thermal (•) injury. Data (mean ± SEM) were analyzed using the Mann-Whitney test. *P < .05.