Two weeks after transplantation of B lineage and stem cell populations into infarcted rat myocardium, the surviving animals underwent follow-up echocardiographic assessment. Representative M-mode echocardiography is shown in A. B is a graph of normal (shaded squares, n = 9), immediate post-ligation (shaded circles, n = 9), sham operated (no ligation, open squares, n = 15), and ligation plus saline injection (open circles, n = 15) animals were included as control animals. Solid triangles represent animals injected with hematopoietic stem cells (HSC) (n = 4); solid diamonds represent animals injected with HSC coinjected with B cells (n = 5); solid circles represent B cell-injected animals (n = 24). B cells cultured overnight at 37°C (n = 11) are represented by solid squares, and B cells cocultured with nonhematopoietic stem cells (NHSCs) cultured overnight at 37°C are represented by patterned squares (n = 18). Each data point represents 1 animal, and horizontal bars are the mean ± SE. Significant differences in the mean values are denoted by *p < 0.05 using analysis of variance with post-hoc analysis using Fisher least significant difference.