Fig. 2. Capacity of IGF-I to protect Null and Null+ cells from loss of extracellular-matrix-induced cell death. Both TVI (A,C) and TVII (B,D) Null and Null+ cells were placed in suspension by seeding on poly-HEMA coated dishes. IGF-I (100 ng/ml) was added to the medium as indicated, and the cells were harvested 20 hours later. Cell viability was determined using trypan blue staining (A,B) or caspase 3 activity (C,D). Open and closed bars represent results for Null and Null+ cells, respectively.