Adhesion of fluorescently labeled human RBCs to rat brain microvasculature. Fluorescently labeled human RBCs were injected (200 to 500 μL) into rats prepared with a cranial window as described in the Materials and Methods. Photomicrographs of video images (original magnification ×40) in two different areas of the rat brain microvasculature are shown. Area (A) focuses on capillary size vessels. Area (B) focuses on postcapillary venules. The white arrows identify fluorescent adherent human RBCs. RBC adhesion was predominately in the capillary and postcapillary venule for both sickle and control erythrocytes (SS-RBCs are shown).