Ultrastructural analysis of particles found in the plasma of p45 NF-E2–deficient adult mice. (A and B) Low-power images of cells in the platelet-rich plasma fraction, showing normal appearance of platelets in control samples (A) but a predominance of RBC fragments (RBC) and fewer, bizarre platelet forms (Plt) in mutant samples (B); bar = 5 μm. (C through E) Higher magnification images of platelets and platelet-like fragments, comparing the normal platelet appearance in controls (C) with large, round, heterogeneous and abnormally organized fragments in p45 NF-E2 knockout mice (D and E). nuc, naked nucleus; bar = 1 μm. (F) High-power view of a representative NF-E2–deficient platelet-like particle, revealing disorganized and abnormal contents, including excess mitochondria (mt) and endoplasmic reticulum (ER), a dense tubular system, and possibly rare abnormal granules (gr?); bar = 1 μm.