Human CD34⁺ cell rolling and arrest in collecting venules and sinusoids of the BM in NOD/SCID mice. CFSE-labeled human CD34⁺ cells purified from mPB were injected into NOD/SCID mice, and the fractions of cells rolling or arrested in collecting venules or sinusoids were determined by IVM analysis of videotapes. Bars represent mean ± SEM. The differences between Cv and sinusoids for the number of rolling and arrested cells are not significant (P = 0.14 and 0.6, respectively). n = 7 different human donors and the same number of mice.