In Countdown #50, Jimmy Olsen interviews an incarcerated Joker about the murder of Duela Dent, who had called herself the Joker's Daughter. The Joker states that he never had any daughter, and expresses awareness of the Multiverse's existence and of shifts in reality. The Joker appears as he did before Batman #655.
All blood is made of the same basic elements, however not all blood is alike. There are eight common blood types. In an emergency, blood type O- can be given to anyone because it is most likely to be accepted by all blood types. O- is the Universal Donor. Type A+ can donate to A+, AB+. Type A- can donate to A-, A+, AB+, AB-.
Donors with type O- red blood cells are referred to as universal donors and their red blood cells can be given to any other blood type. Donors with type AB+ are referred to as universal recipients and can receive red blood cells from any other blood type. Donors with type AB- are universal plasma donors and can give plasma to any other blood type.