Nucleated red blood cell Nucleated red blood cell All vertebrate organisms have hemoglobin-containing cells in their blood and with the exception of mammals, all of these red blood cells contain a nucleus. Mammals represent ~5,500 named species out of ~66,000 vertebrate species, and within this ~8% subgroup, red blood cells are known as erythrocytes or RBCs and lack a cell nucleus in mature organisms. In contrast, a nucleated red blood cell (NRBC), also known by several other names, is a mammalian RBC that contains a cell nucleus. NRBCs occur in normal development as progenitor cells in the erythropoietic lineage and in pathological states. Normally,
U2 Live at Red Rocks: Under a Blood Red Sky in October 1983 to promote U2's companion live mini-LP "Under a Blood Red Sky", which was released the following month. The mini-LP, whose name was later used as a subtitle for the concert film, features eight live songs from the War Tour, two of which ("Gloria" and "Party Girl") were taken from the Red Rocks concert; the other tracks were taken from performances in Boston and West Germany, as U2 thought they were "more developed performances". "U2 Live at Red Rocks: Under a Blood Red Sky" was U2's first home video release, initially released on VHS and Betamax by MCA