Polyploidy was induced in fish by Har Swarup (1956) using a cold-shock treatment of the eggs close to the time of fertilization, which produced triploid embryos that successfully matured. Cold or heat shock has also been shown to result in unreduced amphibian gametes, though this occurs more commonly in eggs than in sperm. John Gurdon (1958) transplanted intact nuclei from somatic cells to produce diploid eggs in the frog, Xenopus (an extension of the work of Briggs and King in 1952) that were able to develop to the tadpole stage. The British scientist J. B. S. Haldane hailed the work for its potential medical applications and, in describing the results, became one of the first to use the word "clone" in reference to animals. Later work by Shinya Yamanaka showed how mature cells can be reprogrammed to become pluripotent, extending the possibilities to non-stem cells. Gurdon and Yamanaka were jointly awarded the Nobel Prize in 2012 for this work. Humans
True polyploidy rarely occurs in humans, although polyploid cells occur in highly differentiated tissue, such as liver parenchyma, heart muscle, placenta and in bone marrow. Aneuploidy is more common. Polyploidy occurs in humans in the form of triploidy, with 69 chromosomes (sometimes called 69, XXX), and tetraploidy with 92 chromosomes (sometimes called 92, XXXX). Triploidy, usually due to polyspermy, occurs in about 2–3% of all human pregnancies and ~15% of miscarriages. The vast majority of triploid conceptions end as a miscarriage; those that do survive to term typically die shortly after birth.
Chronic cerebrospinal venous insufficiency (CCSVI or CCVI) is a term invented by Italian researcher Paolo Zamboni in 2008 to describe compromised flow of blood in the veins draining the central nervous system. Zamboni hypothesized that it might play a role in the cause or development of multiple sclerosis (MS). Zamboni also devised a surgical procedure which the media nicknamed a liberation procedure or liberation therapy, involving venoplasty or stenting of certain veins. Zambonis ideas about CCSVI are very controversial, with significantly more detractors than supporters, and any treatments based on his ideas are considered experimental.There is no scientific evidence that CCSVI is related to MS, and there is no good evidence that the surgery helps MS patients. Zambonis first published research was neither blinded nor did it have a comparison group. Zamboni also did not disclose his financial ties to Esaote, the manufacturer of the ultrasound specifically used in CCSVI diagnosis. The "liberation procedure" has been criticized for possibly resulting in serious complications and deaths, while its purported benefits have not been proven. In 2012, the United States Food and Drug Administration states that it is not clear if CCSVI exists as a clinical entity and that these treatments may cause more harm. In 2017 they emphasized that this use of balloon angioplasty is not an approved use. In a 2017 study Zamboni et al. stated "Venous PTA cannot be recommended for patients with relapsing-remitting multiple sclerosis."