Representative histology of normal and aberrant hematopoiesis in mice. Images shown are either from wild-type C57Bl/6 mice (indicated by i) or from C57Bl/6 Crebbp^+/− mice with MDS/MPN (indicated by ii), as examples of abnormal hematopoietic histology. (A) Compared with (Ai) H&E-stained wild-type BM, (Aii) hypercellular Crebbp^+/− BM demonstrates marked compression and flattening of sinusoidal channels (red arrows and a high magnification of the indicated sinusoidal channels at the bottom) in the medullary cavity. (B-C) Giemsa-stained BM touch preparation and tissue section, respectively, show a myeloid:erythroid (M:E) ratio close to 1.5:1 in (Bi-Ci) wild-type, whereas (Bii-Cii) Crebbp^+/− BM is dominated by mature segmented granulocytes). The yellow dashed line demarks areas of myelopoiesis (M); the red dashed line areas of erythropoiesis (E). (D) A Giemsa-stained wild-type spleen touch preparation contains mostly (Di) mature lymphocytes and occasional erythroid precursors (Di, arrows). In contrast, (Dii) an enlarged Crebbp^+/− spleen shows extramedullary hematopoiesis with erythroid precursors (red dashed lines) and scattered granulocyte precursors with a few interspersed lymphocytes. All images in this review were produced at room temperature, using an Olympus BX51 microscope and a DP72 camera (Olympus, Center Valley, PA). Cellsens digital imaging software v.1.3 (www.olympusamerica.com) was used to capture the images. Magnification: (top panels of A) ×10; (B) ×40; and (bottom panels of A,C,D) ×60. Scale bars, 10 μm.