Proangiogenic activity of rDrm. Chick embryo CAM implants (asterisk indicates gelatin sponge) were loaded with vehicle (A) or 100 ng rDrm (B). Note the numerous blood vessels converging versus the rDrm implant. (C-D) Toluidine blue staining of histologic sections of CAM treated with vehicle (C) or 100 ng rDrm (D). Numerous capillaries filled with nucleated avian erythrocytes are present among the trabeculae of the rDrm-treated sponge (arrows in panel D).