When vessels were divided in quartiles according to vessel diameter (<10 μm, 10–15 μm, 16–23 μm and >23 μm; Figure 2), it became evident that the overall effect of diabetes on VCAM-1 expression in wt mice was predominantly driven by changes in the very small vessels (<10 μm), whereas the overall effect observed in TNFα−/− mice was predominantly driven by changes in the larger vessels (>23 μm). The gene discussed is TNF; the disease is diabetes mellitus.