Effects of rHu-GCSF on posthepsulfam hematopoietic regeneration. rHu-GCSF (10 μg/kg/d) beginning 1 day after hepsulfam treatment and continuing for 21 days did not significantly improve the nadir or duration of postchemotherapy thrombocytopenia (left). Twentyone days of rHu-GCSF (10 μg/kg/d) injections shortened the period of neutropenia (<1 × 10⁹ neutrophils/L) from 22 to 4 days (right); the intensity of the neutropenia was not significantly affected (right). The open symbols depict the counts for untreated hepsulfam controls, and the closed symbols designate counts in rHu-GCSF–treated hepsulfam animals.