Tissue engineers grow penis in the lab
19:00 11 September 02
Sylvia Pagán Westphal, Boston
In a remarkable feat of tissue engineering, major parts of the penises of several rabbits have been replaced with segments grown in a lab from their own cells. The animals were able to use the reconstructed organs to mate.
Researchers have grown lengths of the corpus cavernosum in the lab
The next step is to try to recreate the entire organ from scratch. The technique could make it possible to reconstruct the penises of men who have suffered injuries or those of children born with genital abnormalities.
"If you have a child born with ambiguous genitalia, it's a life-changing event," says Anthony Atala of Harvard Medical School, whose team carried out the work.
It could also provide an alternative to the crude methods currently used to enlarge the organ, such as injecting fat cells or cutting the penis's suspensory ligament and "pulling out" more of the internal part. Instead, a patient would have penile cells removed by a doctor and, a few weeks later, the organ or parts of it grown using the cells could be surgically implanted.
More complex
While the particular nature of the research is likely to attract much attention, it is also one of the most impressive attempts at tissue and organ engineering to date. "The penis is more complex than any of the organs we have engineered so far," says Atala, whose team has already created fully functional bladders that may soon be implanted in people.
The penis is more difficult to recreate because it has more functions and, unlike the bladder, is also a solid organ.
It consists of three main cylinders, encased in an outer layer of connective tissue, skin, blood vessels and nerves. The two biggest cylinders, made of spongy material that swells during an erection, are the corpora cavernosa. The third tube encases the urethra.
Of those structures, the corpus cavernosum is the most challenging to replace or reconstruct. It contains specialised muscle and endothelial cells - the cells that line blood vessels - and its structure is hard to mimic. Yet this is the part that Atala has been able to grow.
Half pressure
His team first extracted three-dimensional scaffolds of collagen from the erectile tissue of rabbits. They also took samples of the specialised muscle and endothelial cells from penises of each of the rabbits destined to receive the implants.
These cells were grown separately at first, and then added to the collagen matrix in the appropriate proportions. After a few days more growth, the result resembled real erectile tissue.
Next, Atala removed the corpora cavernosa from almost the entire length of the exterior part of the penises of 18 rabbits, leaving the nerves and urethra intact. He then replaced them with the engineered erectile tissues. Because the tissues were grown from the rabbits' own cells, there was no problem with immune rejection.
Once they had recovered from the surgery, the rabbits attempted to have sex within 30 seconds of being put in a cage with a female. "They were able to copulate, penetrate and produce sperm," Atala told New Scientist.
More detailed studies revealed that the penises generated about half of the normal pressure of an erect penis. "It's analogous to the penis of a 60-year-old man, versus that of a 30-year-old," says Atala. Details of the work will be published in the October issue of The Journal of Urology.
19:00 11 September 02
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© Copyright Reed Business Information Ltd.
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Google mirror beats Great Firewall of China
15:55 06 September 02
Will Knight
China's widely criticised blocking of the web's most popular search engine Google can be defeated by viewing a strange Google mirror site through a mirror, New Scientist has discovered.
The mirror site, called elgooG, is a parody of the English language version of Google in which all the text on the web pages has been reversed. The text terms used for searches are also entered in reverse. The site, which returns all the same hits as Google, can be accessed from behind China's "great firewall".
Viewing the page using a mirror makes it somewhat easier to read, and would allow someone to find a website. Web site "mirroring" normally involves copying the contents of a site and hosting on a different server. This can be useful if one server is particularly busy.
New Scientist ascertained that elgooG is accessible from China using a system that remotely tests China's internet restrictions. The system was created by two researchers at the Berkman Center for Internet & Society at Harvard Law School in the US.
Routine block
Google has been blocked inside China since at least 1 September. It emerged on Friday that a second search engine Altavista is also restricted. The action has come under criticism from western human rights groups and journalist's organisations.
China's government routinely blocks access to news sites that host content they consider unacceptable, such as the BBC's news site. Web proxies including anonymizer.com and safeweb.com, which can be used to view pages on one site through another, are also blocked.
The reason for the latest restrictions is not clear but observers have speculated that government elections in November could have prompted a crack down on access to information via the internet.
Content cache
Google could have been targeted because it provides a cache of content from other web sites that are already under government blackout. However, Altavista does not.
The country's 45 million internet users can only access the web through government-run ISPs. This means that any site can be blocked easily.
The company behind Google has released programming information that provides remote access to its search capabilities. This means mirror sites can be created without having to duplicate Google's colossal database, though to date New Scientist has only identified elgooG.
15:55 06 September 02
Return to news story
© Copyright Reed Business Information Ltd.
19:00 11 September 02
Sylvia Pagán Westphal, Boston
In a remarkable feat of tissue engineering, major parts of the penises of several rabbits have been replaced with segments grown in a lab from their own cells. The animals were able to use the reconstructed organs to mate.
Researchers have grown lengths of the corpus cavernosum in the lab
The next step is to try to recreate the entire organ from scratch. The technique could make it possible to reconstruct the penises of men who have suffered injuries or those of children born with genital abnormalities.
"If you have a child born with ambiguous genitalia, it's a life-changing event," says Anthony Atala of Harvard Medical School, whose team carried out the work.
It could also provide an alternative to the crude methods currently used to enlarge the organ, such as injecting fat cells or cutting the penis's suspensory ligament and "pulling out" more of the internal part. Instead, a patient would have penile cells removed by a doctor and, a few weeks later, the organ or parts of it grown using the cells could be surgically implanted.
More complex
While the particular nature of the research is likely to attract much attention, it is also one of the most impressive attempts at tissue and organ engineering to date. "The penis is more complex than any of the organs we have engineered so far," says Atala, whose team has already created fully functional bladders that may soon be implanted in people.
The penis is more difficult to recreate because it has more functions and, unlike the bladder, is also a solid organ.
It consists of three main cylinders, encased in an outer layer of connective tissue, skin, blood vessels and nerves. The two biggest cylinders, made of spongy material that swells during an erection, are the corpora cavernosa. The third tube encases the urethra.
Of those structures, the corpus cavernosum is the most challenging to replace or reconstruct. It contains specialised muscle and endothelial cells - the cells that line blood vessels - and its structure is hard to mimic. Yet this is the part that Atala has been able to grow.
Half pressure
His team first extracted three-dimensional scaffolds of collagen from the erectile tissue of rabbits. They also took samples of the specialised muscle and endothelial cells from penises of each of the rabbits destined to receive the implants.
These cells were grown separately at first, and then added to the collagen matrix in the appropriate proportions. After a few days more growth, the result resembled real erectile tissue.
Next, Atala removed the corpora cavernosa from almost the entire length of the exterior part of the penises of 18 rabbits, leaving the nerves and urethra intact. He then replaced them with the engineered erectile tissues. Because the tissues were grown from the rabbits' own cells, there was no problem with immune rejection.
Once they had recovered from the surgery, the rabbits attempted to have sex within 30 seconds of being put in a cage with a female. "They were able to copulate, penetrate and produce sperm," Atala told New Scientist.
More detailed studies revealed that the penises generated about half of the normal pressure of an erect penis. "It's analogous to the penis of a 60-year-old man, versus that of a 30-year-old," says Atala. Details of the work will be published in the October issue of The Journal of Urology.
19:00 11 September 02
Return to news story
© Copyright Reed Business Information Ltd.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Google mirror beats Great Firewall of China
15:55 06 September 02
Will Knight
China's widely criticised blocking of the web's most popular search engine Google can be defeated by viewing a strange Google mirror site through a mirror, New Scientist has discovered.
The mirror site, called elgooG, is a parody of the English language version of Google in which all the text on the web pages has been reversed. The text terms used for searches are also entered in reverse. The site, which returns all the same hits as Google, can be accessed from behind China's "great firewall".
Viewing the page using a mirror makes it somewhat easier to read, and would allow someone to find a website. Web site "mirroring" normally involves copying the contents of a site and hosting on a different server. This can be useful if one server is particularly busy.
New Scientist ascertained that elgooG is accessible from China using a system that remotely tests China's internet restrictions. The system was created by two researchers at the Berkman Center for Internet & Society at Harvard Law School in the US.
Routine block
Google has been blocked inside China since at least 1 September. It emerged on Friday that a second search engine Altavista is also restricted. The action has come under criticism from western human rights groups and journalist's organisations.
China's government routinely blocks access to news sites that host content they consider unacceptable, such as the BBC's news site. Web proxies including anonymizer.com and safeweb.com, which can be used to view pages on one site through another, are also blocked.
The reason for the latest restrictions is not clear but observers have speculated that government elections in November could have prompted a crack down on access to information via the internet.
Content cache
Google could have been targeted because it provides a cache of content from other web sites that are already under government blackout. However, Altavista does not.
The country's 45 million internet users can only access the web through government-run ISPs. This means that any site can be blocked easily.
The company behind Google has released programming information that provides remote access to its search capabilities. This means mirror sites can be created without having to duplicate Google's colossal database, though to date New Scientist has only identified elgooG.
15:55 06 September 02
Return to news story
© Copyright Reed Business Information Ltd.
