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Xenotransplantation (''xenos-'' from the Greek meaning "foreign"), is the transplantation of living cells, tissues or organs from one species to another.〔(Xenotransplantation ). Definition by the World Health Organization〕 Such cells, tissues or organs are called xenografts or xenotransplants. In contrast, the term allotransplantation refers to a same-species transplant. Human xenotransplantation offers a potential treatment for end-stage organ failure, a significant health problem in parts of the industrialized world. It also raises many novel medical, legal and ethical issues. A continuing concern is that many animals, such as pigs, have a shorter lifespan than humans, meaning that their tissues age at a quicker rate. Disease transmission (xenozoonosis) and permanent alteration to the genetic code of animals are also causes for concern. A few successful cases of xenotransplantation are published. It is not uncommon for patients and physicians to use the term "allograft" imprecisely to refer to either allograft (human-to-human) or xenograft (animal-to-human), but it is helpful scientifically (for those searching or reading the scientific literature) to maintain the more precise distinction in usage. ==History== An American infant girl known as "Baby Fae" with hypoplastic left heart syndrome was the first infant recipient of a xenotransplantation, when she received a baboon heart in 1984. The procedure was performed by Leonard L. Bailey at Loma Linda University Medical Center in Loma Linda, California. Fae died 21 days later due to a humoral-based graft rejection thought to be caused mainly by an ABO blood type mismatch, considered unavoidable due to the rarity of type O baboons. The graft was meant to be temporary, but unfortunately a suitable allograft replacement could not be found in time. Xenotransplantation of human tumor cells into immunocompromised mice is a research technique frequently used in oncology research. It is used to predict the sensitivity of the transplanted tumor to various cancer treatments; several companies offer this service, including the Jackson Laboratory〔(JAX® In Vivo Xenograft Services ). ''JAX® NOTES'' Issue 508, Winter 2008〕 and Altogen Labs. Human organs have been transplanted into animals as a powerful research technique for studying human biology without harming human patients. This technique has also been proposed as an alternative source of human organs for future transplantation into human patients. For example, researchers from the Ganogen Research Institute transplanted human fetal kidneys into rats which demonstrated life supporting function and growth. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「xenotransplantation」の詳細全文を読む スポンサード リンク
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