http://www.dailymail.co.uk/health/article-1286266/Scientists-grow-laboratory-liver-giving-hope-millions-diseased-organs.html##ixzz0u3oK7EdV
Scientists have grown a liver in a laboratory, offering fresh hope to hundreds of thousands of patients with diseased and damaged organs.
It raises the prospect of those in need of transplants one day being offered livers that are ‘made to order’.
The first pieces of lab-grown livers could be used in hospitals within just five years, the researchers said.
Patches of artificial tissue could be used to repair livers damaged by injury, disease, alcohol abuse and paracetamol overdose.
Other possibilities include sections of artificial livers to keep those needing transplants alive – in much the same way as a dialysis machine is used to treat kidney failure.
At least one million of Britons live with liver disease and it claims more than 16,000 lives a year – more than diabetes and traffic accidents combined. Up to 600 transplants are carried out a year.
The latest experiments, which were carried out on animal livers, are still in the early stages but could one day lead to an alternative supply of organs.
The process began with a donor liver being ‘washed’ in detergent, stripping it of its cells, leaving only a collagen and blood vessel ‘scaffold’ in which the new liver cells could grow.
The U.S. scientists then injected it with up to 200 million healthy liver cells, in four shots, each ten minutes apart.
The cells spread across the scaffold, and, provided with an artificial blood supply, the liver survived in a petri dish for up to ten days, the journal Nature Medicine reports.
Tests showed that, just like a real liver, it was capable of breaking up toxins.
The researchers, from Massachusetts General Hospital, Boston, also transplanted the liver into a rat, for several hours.
Lead researcher Dr Korkut Uygun said: ‘As far as we know, a transplantable liver graft has never been constructed in a laboratory setting before.
‘Even though this is very exciting and promising, it is a proof-of-concept study only. Much more work will be required to make long-term functional liver grafts that can actually be transplanted into humans.
‘We haven’t been able to go beyond several hours in rats, but it’s a great start.’
Hurdles to overcome include creating a liver with all the types of cells needed for full function, including specialised cells that destroy bacteria and other invaders.
A spokesman for the British Liver Trust said: 'We find these insights very interesting, particularly the concept of making sub-standard livers suitable for transplantation. The results from this study holds promise however it is a long way from helping liver patients.
'We desperately need to increase the supply of donor organs and see new treatments for advanced liver disease. Everyone has a role to play by joining the organ donor register and talking to their families about their wishes.'
Sunday, July 18, 2010
Saturday, July 17, 2010
Scientists Theorize Why Black Athletes Run Fastest
Twenty-eight of the last 38 world record holders in the men's 100-meter dash have been black athletes, and researchers at two universities think they know why.
A new study by researchers at Howard University, a historically black school in Washington D.C., and Duke University in North Carolina suggests why black athletes may outperform athletes of other races in running events. Physical differences in the length of the limbs and the structure of the body mean the center of gravity tends to be higher in the bodies of black people, the researchers say.
Since 1968, the world record holders in the men's 100-meter dash have been black athletes. And since 1912, when the International Association of Athletics Federations started keeping track of the record holders in that event, only 10 non-black athletes out of 38 individuals have held the title.
"There is a whole body of evidence showing that there are distinct differences in body types among blacks and whites," said researcher Edward Jones, who researches adolescent obesity, nutrition and body composition at Howard University. "These are real patterns being described here. Whether the fastest sprinters are Jamaican, African or Canadian, most of them can be traced back generally to Western Africa."
Why center of gravity matters
Although there are also cultural factors at work, it all comes down to body makeup, Jones said.
"Blacks tend to have longer limbs with smaller circumferences, meaning that their centers of gravity are higher compared to whites of the same height," said Adrian Bejan, Jones' co-author, an engineering professor at Duke University. "Asians and whites tend to have longer torsos, so their centers of gravity are lower."
"These differences are small, and we don't really see them when we look at someone," Bejan told Life's Little Mysteries. "We are only rarely struck by how long someone's legs are."
But these small differences certainly matter in races lasting less than 10 seconds, Bejan said.
The height of a person's center of gravity affects how fast his feet are moving when they hit the ground, Bejan said. Each step a runner takes is like falling except the athlete breaks the fall with his foot. So the feet of a person with a higher center of gravity will hit the ground faster than someone with a lower center of gravity.
Torsos and legs
In the study, the scientists gathered data available from the militaries of 17 nations. Militaries measure their recruits for uniform fittings and are a reliable source of data, Bejan said. To approximate torso length, the scientists compared the average height of the military men with their sitting height - the distance from a chair to the top of the head.
Results showed the average sitting height of blacks was about 1.5 inches (3 cm) shorter than that of whites who were the same height. This means that, among blacks and whites of the same height, the legs of blacks were longer (think of a high-waisted person), while the torsos of whites were longer.
This physical difference gives a black athlete an advantage, even against an athlete of another race is who is taller and has a higher center of gravity, said Bejan. From a physics perspective, Bejan said, the legs do the work of running and the torso of the body is just extra weight that the legs must carry, so the race goes to the runners with longer legs and shorter torsos.
By contrast, whites tend to have the advantage in swimming, where a longer torso allows for faster speeds.
"Swimming actually generates a wave. The sport is the art of surfacing on that wave. When the wave is bigger - because the torso is longer - they go faster," Bejan said.
The study was published online this week in the International Journal of Design and Nature and Ecodynamics.
A new study by researchers at Howard University, a historically black school in Washington D.C., and Duke University in North Carolina suggests why black athletes may outperform athletes of other races in running events. Physical differences in the length of the limbs and the structure of the body mean the center of gravity tends to be higher in the bodies of black people, the researchers say.
Since 1968, the world record holders in the men's 100-meter dash have been black athletes. And since 1912, when the International Association of Athletics Federations started keeping track of the record holders in that event, only 10 non-black athletes out of 38 individuals have held the title.
"There is a whole body of evidence showing that there are distinct differences in body types among blacks and whites," said researcher Edward Jones, who researches adolescent obesity, nutrition and body composition at Howard University. "These are real patterns being described here. Whether the fastest sprinters are Jamaican, African or Canadian, most of them can be traced back generally to Western Africa."
Why center of gravity matters
Although there are also cultural factors at work, it all comes down to body makeup, Jones said.
"Blacks tend to have longer limbs with smaller circumferences, meaning that their centers of gravity are higher compared to whites of the same height," said Adrian Bejan, Jones' co-author, an engineering professor at Duke University. "Asians and whites tend to have longer torsos, so their centers of gravity are lower."
"These differences are small, and we don't really see them when we look at someone," Bejan told Life's Little Mysteries. "We are only rarely struck by how long someone's legs are."
But these small differences certainly matter in races lasting less than 10 seconds, Bejan said.
The height of a person's center of gravity affects how fast his feet are moving when they hit the ground, Bejan said. Each step a runner takes is like falling except the athlete breaks the fall with his foot. So the feet of a person with a higher center of gravity will hit the ground faster than someone with a lower center of gravity.
Torsos and legs
In the study, the scientists gathered data available from the militaries of 17 nations. Militaries measure their recruits for uniform fittings and are a reliable source of data, Bejan said. To approximate torso length, the scientists compared the average height of the military men with their sitting height - the distance from a chair to the top of the head.
Results showed the average sitting height of blacks was about 1.5 inches (3 cm) shorter than that of whites who were the same height. This means that, among blacks and whites of the same height, the legs of blacks were longer (think of a high-waisted person), while the torsos of whites were longer.
This physical difference gives a black athlete an advantage, even against an athlete of another race is who is taller and has a higher center of gravity, said Bejan. From a physics perspective, Bejan said, the legs do the work of running and the torso of the body is just extra weight that the legs must carry, so the race goes to the runners with longer legs and shorter torsos.
By contrast, whites tend to have the advantage in swimming, where a longer torso allows for faster speeds.
"Swimming actually generates a wave. The sport is the art of surfacing on that wave. When the wave is bigger - because the torso is longer - they go faster," Bejan said.
The study was published online this week in the International Journal of Design and Nature and Ecodynamics.
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