1. Laboratory of Experimental Hematology, Department of Biology, Graduate School of Arts and Science, New York University, New York, N.Y.; and the Department of Medicine (Hematology), Mount Sinai School of Medicine, New York, N.Y.
2. Laboratory of Experimental Hematology, Department of Biology, Graduate School of Arts and Science, New York University, Washington Square, New York, N.Y.
3. Department of Biology, New York University, Washington Square, New York, N.Y.
4. Mount Sinai School of Medicine, New York, N.Y.