A head transplant is a surgical operation involving the grafting of one organism's head onto the body of another. Head transplantation involves decapitating the patient. Head transplants have been performed on dogs, monkeys and rats by surgeons, although all the animals were unable to move and died shortly afterwards. There are plans for the first human head transplant.
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History
Dogs
Charles Claude Guthrie succeeded in grafting one dog's head onto the side of another's neck on May 21, 1908.
Sergei Brukhonenko developed a device called the autojektor, a primitive Heart-lung machine. Brukhonenko carried out several studies on canines with the autojektor, including a famous experiment where the machine was attached to the decapitated head of a dog, depicted in the 1940 documentary Experiments in the Revival of Organisms. The head remained in a semi-conscious state and responded to simple stimuli such as the sound of a hammer or the administration of eye drops. This experiment provides a potential example of how to keep a donor's head alive while the body of the recipient is prepared. While no further experiments of this type were carried out, a second autojektor for use on humans was developed by Brukhonenko in the same year, with modern ECMO machines bearing many similarities to the autojektor.
Vladimir Demikhov experimented with dog head transplantation in the Soviet Union in the 1950s. His transplant subjects typically died due to immune reactions.
In 1959, China claimed that they had succeeded in transplanting the head of one dog to the body of another twice.
Dr. Vladimir Demikhov's work, among others, was deeply influential for the future science of organ transplant, as he pioneered many different forms of transplant in the 1940s and 1950s, including the use of immuno-suppressants. His work was well known by other scientists and during the 1950s and 1960s, numerous heart transplants were performed on dogs in the United States by Dr. Norman Shumway of Stanford University and Dr. Richard Lower of the Medical College of Virginia. The first human heart transplant was performed by Christiaan Barnard in South Africa, in 1967; however, as they did not have the chemical agents to utilize immuno-suppressants, the patient receiving the transplant died.
Monkeys
On March 14, 1970, a group of scientists from Case Western Reserve University School of Medicine in Cleveland, Ohio, led by Robert J. White, a neurosurgeon and a professor of neurological surgery who was inspired by the work of Vladimir Demikhov, performed a highly controversial operation to transplant the head of one monkey onto another's body. The procedure was a success to some extent, with the animal being able to smell, taste, hear, and see the world around it. The operation involved cauterizing arteries and veins carefully while the head was being severed to prevent hypovolemia. Because the nerves were left entirely intact, connecting the brain to a blood supply kept it chemically alive. The animal survived for some time after the operation, even at times attempting to bite some of the staff. In 2001, Dr. White successfully repeated the operation on a monkey.
White later wrote:
What has been accomplished in the animal model - prolonged hypothermic preservation and cephalic transplantation, is fully accomplishable in the human sphere. Whether such dramatic procedures will ever be justified in the human area must wait not only upon the continued advance of medical science but more appropriately the moral and social justification of such procedural undertakings.
Rats
In 2002, other head transplants were also conducted in Japan on rats. Unlike the head transplants performed by Dr. White, however, these head transplants involved grafting one rat's head onto the body of another rat that kept its head. Thus, the rat ended up with two heads. The scientists said that the key to successful head transplants was to use low temperatures.
The ability of fusogens like PEG and chitosan to rebridge a transected spinal cord has been confirmed by a 2014 German study: paraplegic rats recovered motricity within 1 month.
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Human head transplant project
In 2015, Italian neurosurgeon Sergio Canavero has said the procedure (head anastomosis venture) might be feasible - with improved technology and more accurate ability to keep neural tissue perfused - before the end of 2017, when he intends to perform the procedure in either the United States or China. While an attempt at carrying out a human head transplant has yet to take place, Sergio Canavero has voiced his intention to do so, having dedicated 30 years to researching the procedure. He has devised a two-part procedure for the transplant, named HEAVEN (HEad Anastomosis VENture) and GEMINI (subsequent spinal cord transplant).
A 31-year-old Russian programmer Valery Spiridonov with Werdnig-Hoffmann disease (type I spinal muscular atrophy) and rapidly declining health has volunteered to offer his head for the study. The donor is to be chosen by screening for similar height, build, and immunotype.
Procedure
The actual procedure will be as follows: Two teams will work in concert, making deep incisions around each patient's neck and exposing the carotid and vertebral arteries, jugular vein, and spine. The muscles would be color-coded for linkage. Three other cuts will be done, for later spinal stabilization and access to the carotids, trachea, and esophagus. Next is the most crucial part: cutting of the spinal cord. Using a $200,000 diamond nanoblade and an operating microscope, the two spinal cords will be cut cleanly simultaneously as the last step before separation. Once the recipient's head is separated, it must be transferred to the donor's body to the tubes that connect it to the donor's circulation. The procedure must be done within an hour to ensure minimal brain damage. The cords will be adjusted and fused within 1-2 minutes, chitosan-PEG glue infused in the blood stream over 15-30 minutes and loose sutures applied to the body to the recipient head to theoretically immediately rewarm the recipient head. The dura will also be sewn in a watertight fashion with wires and clamps. The trachea, esophagus, vagi, and phrenic nerves would also be connected in a similar fashion to how the spinal cord was attached. The muscles will be connected according to the markings made. The skin would be sewn by a plastic surgeon for maximal cosmetic results. Once the procedure is finished, the recipient will be kept in a coma for 3-4 weeks, to prevent any spontaneous ruptures to the sutures during recovery. He would also be given medication to suppress immune response, similar to how it would be given for any other transplant patient.
Current progress
Current progress is being made as Dr. Canavero's collaborators continue research. Dr. Xiaoping Ren of Harbin Medical University of China and his team recently completed a monkey head transplant using Canavero's research. The spinal cord was not connected for the monkey as the purpose was to see if the blood supply worked. The monkey survived the procedure without any complications but was only kept alive for 20 hours for ethical reasons. They are also testing on human corpses to prevent injury. C-Yoon Kim of Konkuk University School of Medicine in South Korea also published a study in Surgical Neurology International which showed how the team reestablished motor movements in mice whose neck spinal cords had been severed and re-fused. A video was also released.
Popular opinion
Popular opinion about potential head transplantation has been generally negative, despite Sergio Canavero's claims that he will be able to perform a successful head transplant by 2017. These claims against Canavero do not take a moral or ethical stance, but rather focus on the state of technology and the timeframe in which Canavero says he will be able to successfully conduct the procedure.
Robert J. White, the scientist who transplanted the monkey's head, became a leading target for protestors. One interrupted a banquet in his honor by offering him a bloody replica of a human head. Others called his house asking for "Dr. Butcher". When White testified in a civil hearing about Dr. Sam Sheppard's murder case, lawyer Terry Gilbert compared Dr. White to Dr. Frankenstein. The People for the Ethical Treatment of Animals described White's experiments as "epitomizing the crude, cruel vivisection industry".
Popular culture
- As per Hindu mythology, the head of Lord Ganesha was replaced with the head of an elephant by his father Lord Shiva.
- Daksha Prajapati, the son of Brahma, received a goat's head after being beheaded by Lord Shiva.
- Arthur Nagan or "Gorilla-Man", Marvel Comics character that transplanted his head onto a gorilla's body
- Professor Dowell's Head (1925), science-fiction novel by Alexander Belyaev
- The Brain That Wouldn't Die (1962), science-fiction/horror film
- The Thing with Two Heads (1972), science fiction film
- The Incredible Two-Headed Transplant (1971), science fiction/horror film
- Professor Dowell's Testament (1985), science fiction film
Source of the article : Wikipedia
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