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  Karl Landsteiner demonstrated that people have different blood types, which are determined by markermolecules on their red blood cells.
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  30 years later Charles Drew demonstrated that emergency transfusions could successfully be done with plasma if whole blood was not available.
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  Christiaan Barnad, a South African surgeon, performed the first transplant of a human heart.
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  An artificial heart, developed by Robert Jarvik, was implanted into a patient by surgeon William DeVries at the University of Utah.
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  The United States government approved a device that uses a laser beam to burn away material causing blockage in some arteries.