20th century
Only in 1901, when the Austrian Karl Landsteiner discovered three human blood groups (O, A, and B), did blood transfusion achieve a scientific basis and become safer.Landsteiner discovered that adverse effects arise from mixing blood from two incompatible individuals. He found that mixing incompatible types triggers an immune response and the red blood-cells clump. The immunological reaction occurs when the receiver of a blood transfusion has antibodies against the donor blood-cells. The destruction of red blood cells releases free hemoglobin into the bloodstream, which can have fatal consequences. Landsteiners work made it possible to determine blood group and allowed blood transfusions to take place much more safely. For his discovery he won the Nobel Prize in Physiology and Medicine in 1930; many other blood groups have been discovered since.George Washington Crile is credited with performing the first surgery using a direct blood transfusion in 1906 at St. Alexis Hospital in Cleveland while a professor of surgery at Case Western Reserve University.Jan Janský also discovered the human blood groups; in 1907 he classified blood into four groups: I, II, III, IV. His nomenclature is still used in Russia and in states of the former USSR, in which blood types O, A, B, and AB are respectively designated I, II, III, and IV. Dr. William Lorenzo Mosss (1876–1957) Moss-blood typing technique of 1910 was widely used until World War II.William Stewart Halsted, M.D. (1852–1922), an American surgeon,  performed one of the first blood transfusions in the United States.
Osteochondritis is a painful type of osteochondrosis where the cartilage or bone in a joint is inflamed.It often refers to osteochondritis dissecans (OCD). The term dissecans refers to the "creation of a flap of cartilage that further dissects away from its underlying subchondral attachments (dissecans)".The other recognized types of osteochondritis are osteochondritis deformans juvenilis (osteochondritis of the capitular head of the epiphysis of the femur) and osteochondritis deformans juvenilis dorsi (osteochondrosis of the spinal vertebrae, also known as Scheuermanns disease).Osteochondritis, and especially osteochondritis dissecans, can manifest in animals as a primary cause of elbow dysplasia, a chronic condition in some dog breeds. References


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