Figure 1.

Impaired oxygen transport and the abnormal morphology of erythrocytes in Per2-null mice. A, oxygen consumption was determined at 15-s intervals for 24 h (n = 5 mice/group). B, PO₂ (left) and SaO₂ (right) were decreased in Per2-null mice. Results represent mean ± S.D. (error bars); n = 5 in each group. *, p < 0.05. C, morphology of peripheral red blood cells. Shown are Wright–Giemsa–stained (left) light microscopy and scanning-electron (right) microscopy of peripheral blood smears of WT and Per2-null mice. Arrows, abnormal morphology of erythrocytes in the Per2-null mice. Bar, 10 μm (left) and 5 μm (right).