10. Samuel KountzSamuel Kountz developed the Belzer kidney perfusion machine that preserves a kidney for up to 50 hours from the time it is removed from a donor’s body. The device is standard equipment in hospitals and laboratories worldwide, according to a Wikipedia page about Kountz.
Kountz was also the first to perform a successful kidney transplant between two humans who weren’t twins. He also discovered that large doses of methylprednisolone, a steroid drug, could reverse acute rejection of kidneys that were transplanted.
He started his surgical training at Stanford University School of Medicine where he studied the field of organ transplantation and decided to specialize in transplant surgery.