Robert Jarvik animal in the lab for 10 days. Kolff assigned Jarvik to design a new heart that would overcome the problems of the Kwan-Gett heart, eventually culminating with the Jarvik-7 device. In 1982, the team carried out an artificial heart implant - the second ever, 13 years after Domingo Liotta and Denton Cooley's first in 1969. William DeVries first implanted the Jarvik-7 into retired dentist Barney Clark at the University of Utah on December 2, 1982. Clark required frequent visits to the hospital for the next 112 days, after which he died. During frequent press conferences to update the patient's condition,
Human artificial chromosome by these vectors not only leads to different expression levels, but the inserts also disrupt the original genome. HACs differ in this regard, as they are entirely separate chromosomes. This separation from existing genetic material assumes that no insertional mutants would arise. This stability and accuracy makes HACs preferable to other methods such as viral vectors, YACs and BACs. HACs allow for delivery of more DNA (including promoters and copy-number variation) than is possible with viral vectors. Yeast artificial chromosomes and bacterial artificial chromosomes were created before human artificial chromosomes, which first appeared in 1997. HACs are useful in expression