"Scientists use magnetic nanotech to safely rewarm frozen tissues for transplant"

"Recently, Yadong Yin and a team developed magnetic nanoparticles -- effectively extremely tiny bar magnets -- that, when exposed to alternating magnetic fields, generated heat. And that heat rapidly thawed animal tissues stored at -238 degrees Fahrenheit (-150 degrees Celsius) in a solution of the nanoparticles and a cryoprotective agent."

"The researchers worried, however, that uneven distribution of the nanoparticles within the tissues might trigger overheating where the particles congregated, which could lead to tissue damage and toxicity from the cryoprotective agent at elevated temperatures."

To reduce risk of uneven warming, the researchers developed "a two-stage approach that more finely controls nanowarming rates."

"In the first stage of thawing, as before, an alternating magnetic field initiated rapid rewarming of animal tissues."

"As the samples approached the melting temperature of the cryoprotective agent, the researchers applied a horizontal static magnetic field."

"The second field realigned the nanoparticles, effectively tapping the brakes on heat production."

"The heating slowed fastest in areas with more nanoparticles, which dampened concerns about problematic hotspots."

The research paper is paywalled so I'm just giving you quotes from the popular news article.

Scientists use magnetic nanotech to safely rewarm frozen tissues for transplant

#organtransplants #medicine #nanotechnology #cryogenics

"Surgeons in Japan have transplanted kidney tissue from one rat fetus to another, while the recipient was still in its mother's womb."

Whoa.

"In their study, Takashi Yokoo, a nephrologist at Jikei University School of Medicine in Tokyo, and his colleagues genetically modified rats to express a green fluorescent protein in their kidneys, so that the tissue could be tracked. They then extracted the green kidney tissue from rat fetuses, and used a tiny needle to insert it under the skin of the backs of 18-day-old rat fetuses developing in their mothers' wombs. The rat pups were born after the normal gestation period of around 22 days."

"The tissue gradually developed, forming waste-filtering units known as glomeruli and well-divided inner and outer kidney structures. Two-and-a-half weeks later, the kidneys began to produce urine. 'The timeline is considered to be almost identical to normal development,' says Yokoo. But because the transplanted kidney was not connected to the ureter, the urine had nowhere to go, so the researchers drained the kidney continuously until the rats were euthanized at around five months of age."

"Of the nine fetuses that underwent surgical transplants in four pregnant rats, eight developed fluorescent-green kidneys. In the ninth fetus, the transplanted tissue probably did not embed successfully."

"A close look at the kidneys revealed that the fetuses' blood vessels had grown inside the donated tissue, which made them less likely to be rejected by the immune system. A major cause of organ-transplant rejection is incompatibility between donor blood vessels and the host's body."

First fetus-to-fetus transplant demonstrated in rats

#discoveries #organtransplants