Brain-Machine Interface – Avatars Of The Future, A Reality

Brain-machine interface lets monkeys move two virtual arms with minds: study

Xinhua | 2013-11-7 | Global Times

 

US researchers said Wednesday that monkeys in a lab have learned to control the movement of both arms on an avatar using just their brain activity.

The findings, published in the US journal Science Translational Medicine, advanced efforts to develop bilateral movement in brain-controlled prosthetic devices for severely paralyzed patients, said researchers at Duke University, based in Durham, the state of North Carolina.

To enable the monkeys to control two virtual arms, the researchers recorded nearly 500 neurons from multiple areas in both cerebral hemispheres of the animals’ brains, the largest number of neurons recorded and reported to date.

Millions of people worldwide suffer from sensory and motor deficits caused by spinal cord injuries. Researchers are working to develop tools to help restore their mobility and sense of touch by connecting their brains with assistive devices.

The brain-machine interface approach holds promise for reaching this goal. However, until now brain-machine interfaces could only control a single prosthetic limb.

“Bimanual movements in our daily activities — from typing on a keyboard to opening a can — are critically important,” senior author Miguel Nicolelis, professor of neurobiology at Duke University School of Medicine said in a statement. “Future brain- machine interfaces aimed at restoring mobility in humans will have to incorporate multiple limbs to greatly benefit severely paralyzed patients.”

Nicolelis and his colleagues studied large-scale cortical recordings to see if they could provide sufficient signals to brain-machine interfaces to accurately control bimanual movements.

The monkeys were trained in a virtual environment within which they viewed realistic avatar arms on a screen and were encouraged to place their virtual hands on specific targets in a bimanual motor task. The monkeys first learned to control the avatar arms using a pair of joysticks, but were able to learn to use just their brain activity to move both avatar arms without moving their own arms.

As the animals’ performance in controlling both virtual arms improved over time, the researchers observed widespread plasticity in cortical areas of their brains. These results suggested that the monkeys’ brains may incorporate the avatar arms into their internal image of their bodies, a finding recently reported by the same researchers in the journal Proceedings of the National Academy of Sciences.

The researchers also found that cortical regions showed specific patterns of neuronal electrical activity during bimanual movements that differed from the neuronal activity produced for moving each arm separately.

The study suggested that very large neuronal ensembles — not single neurons — define the underlying physiological unit of normal motor functions, the researchers said, adding that small neuronal samples of the cortex may be insufficient to control complex motor behaviors using a brain-machine interface.

“When we looked at the properties of individual neurons, or of whole populations of cortical cells, we noticed that simply summing up the neuronal activity correlated to movements of the right and left arms did not allow us to predict what the same individual neurons or neuronal populations would do when both arms were engaged together in a bimanual task,” Nicolelis said. “This finding points to an emergent brain property — a non-linear summation — for when both hands are engaged at once.”

Mutant Gene Discovery

Mutant gene discovery will help research

Xinhua | 2013-11-7 | Global Times

 

Chinese doctors have discovered and registered a new mutant gene for alpha-thalassemia, first of its kind worldwide, an advance that enriches the gene database to assist researches into cures for genetic disease.

Li Youqiong and colleagues from the People’s Hospital of Guangxi Zhuang Autonomous Region, discovered this gene, a 21.9, after a series of experiments on a carrier of the hereditary disease in 2011.

Thalassemia is a disease where the carrier is missing or has malfunctioning genes responsible for making hemoglobin, the blood protein that helps to carry oxygen around the body.

The hemoglobin molecule has subunits commonly referred to as alpha and beta.

The mutant gene was identified by the end of 2012 before it was added to the GenBank database in the US-based National Center for Biotechnology Information(NCBI) and then disclosed to public on Oct.1 2013, according to Li.

There is no effective cure for alpha-thalassemia, and the discovery of the new mutation will help prevention and research into the disease while preparing theoretical basis for future gene therapy.

There are three main genetic sequence databases worldwide, which comprises the DNA Data bank of Japan(DDBJ),the European Molecular Biology Laboratory(EMBL) and GenBank at NCBI. These three organizations exchange data on a daily basis.

Gender Imbalance Troubles China

2010-07-08 18:42 | The Economic Observer
With a severe gender imbalance among young Chinese, China is about to face a lot of problems.According to a Blue Paper on Society released by the China Academy of Social Science, because of the serious gender imbalance among Chinese under the age of 19, ten years later, tens of thousands of male Chinese of marriageable age will have difficulty finding a wife.It is not just the marriage market that will be influenced.In agricultural areas, unmarried young men over 25 years old are everywhere; in rural kindergartens and primary schools, the number of male students is obviously higher than that of females. In the Yangtze River Delta, Pearl River Delta and southeast Fujian Province where the local economies are dominated by the manufacturing and service industry, because of the severe shortage of women aged between 18 and 25, clothing factories have no choice but to hire young men.

China has entered a society where the number of men far exceeds that of women.

“China’s high sex ratio has lasted for over 20 years, its accumulated effects are becoming obvious,” Yuan Xin, a professor with Nankai University’s population and development research institute, said.

The sex ratio at birth under normal circumstances, should be 103 to 107 male infants for every 100 female babies. Because the death ratio of baby boys is higher than that of girls, the number of boys and girls will be close to equal when they are reach the age of marriage.

But in China, the sex ratio has been increasing since the 1980s. In 1982 when China conducted its third national population census, the number of male births for every 100 females was 108.47; in 1990, it rose to 111; in 2000, it was 119 and in 2005, it jumped to 120.49, 13. The male population at that point was 13 percent higher than that of females.

“In a short period of over 20 years, the gender imbalance has expanded quickly from eastern provinces to western, from rural areas to urban cities. Now it has almost covered the whole country,” Yuan Xin said. In 1982, only 18 provinces had a relatively high sex ratio while in 2005, all provinces, except Tibet, had a high sex ratio and three provinces had a ratio exceeding 130.

The gender imbalance will not only produce a large number of single young men, but also will give rise to a series of social problems.

Based on statistics provided by the National Bureau of Statistics, with the size of the male population aged zero to 19 being 23 million more than that of the female population, in the next ten years, every year there will be 1.2 million more men reaching marriageable age than women, forcing the former to seek wives in less-developed regions or search for younger females. The final result will be that young men in poor areas will be edged out of the marriage market, which, according to Tian Xueyuan who is the deputy director of the China Population Association, will give rise to a black market of “wife selling” and thus threaten social stability.

In recent years, 36,000 women have been sold and sent to Zhejiang Province to marry local men, statistics from the local public security bureau show. Most of these women are from underdeveloped regions like Yunnan, Guizhou, Sichuan and Hubei.

In the mountainous area connecting Guangxi Province and Vietnam where the economy is poor, men are forced to marry brides who have illegally entered China from Vietnam.

“The narrowing of the marriage market has produced a large number of single men. What is worse, it is the impoverished who are bearing the consequences,” Tian Xueyuan said.

The gender imbalance will also give a heavy blow to the job market. A textile factory owner, Yuan Xin, who is doing business in Guangzhou, Hangzhou and Shanghai said, said the sex ratio in many textile factories has reached up to four to six males per one female; some factories have even closed due to a lack of female laborers. Yaun Xin said that excess of male laborers would intensify the competition in the job market and make it even more difficult for women to find jobs. Additionally, because of the shortage of females, in some sectors, men would have to take positions which formerly belonged to women, while in some other sectors, men would face more severe competition.

What has caused such an unbalanced sex ratio? The answer is multi-faceted.

One answer is the advanced technology which allows people to know the sex of fetuses when a woman is only four-months pregnant or even less. Male fetuses will kept alive while female fetuses will be aborted.

The technology, called type-B ultrasonic, though prohibited by Chinese laws to be used on pregnant women, is still available in some clinics in Chinese cities, towns and villages, especially in some villages surrounded by cities.

Those clinics, always disguised to be lawful outpatient hospitals or pharmaceutical stores, will inspect the sex of the fetus through a B-type ultrasonic ultrasound and if it is a female, they will ask a doctor, who works for a local hospital and wants to earn extra money, to perform an abortion.

But that is not the complete answer.

“The core of the problem lies in the traditional view which holds that men more important than women,” Tian Xueyuan said.

Though the Chinese government has made it clear that women are equal to men under law, many Chinese parents and families still consider men more important than women and boys better than girls because men are more capable of supporting families and will continue the family line.

According to Yang Juhua, a professor with Renmin University, the unequal social status between male and females is still obvious in Chinese society. Aside from education levels, women are still suffering from disadvantages in many fields. Their wages are still lower than that of men in same-level positions and they are more likely to be refused when competing for university acceptance or job vacancies with male peers with the same qualifications. Additionally, Chinese women play a much weaker role in state affairs than their foreign counterparts. Females only account for one fifth of the total officials in government, party organizations and public agencies,

Edited by Rose Scobie | Original Source People\’s Daily

 

Replacing the Organ Donor

Lab-grown human cells used to recreate liver functions, hope to replace the organ donor

By Jacob Kastrenakes   on July   3, 2013 04:02 pm    |     Email@jake_k

Using small pieces of human liver that were grown from stem cells, a team led by researchers at Japan’s Yokohama City University was able to significantly restore liver function in mice through only a simple transplant — and they hope to eventually use the same method to save human lives. The team took tiny, lab-grown “liver buds” and inserted them into mice, where within two days the cells hooked into surrounding blood vessels and began performing natural functions of the liver. Though the team has yet to track the long-term health of the mice following the procedure, Nature reports that the animals remained alive and well despite prior liver issues.

Having only been demonstrated on mice, the method is still being considered a proof of concept. But the hope is that its immediately promising results can soon be applied to regenerative medicine. The short supply of liver donors has made growing replacements a high priority for interested researchers, but the Yokohama team’s work — which was published today in Nature — remains a preliminary step toward that goal: one of the team’s leaders told Nature that testing the process in humans is still years away. Among the biggest hurdles is simply the difficulty of growing enough cells to actually test them in human patients.

Nitric Oxide – Build Muscle

The Surprising New Tricks Pros Are Using to Build Muscle

Reading about sports these days, we are constantly bombarded with news of top notch athletes being exposed for using illegal steroids.

Steroid use involves huge costs, legal issues, and above all, potential health problems. With such risks, you wonder why anyone would be tempted to go this route.

Fortunately, steroid use may eventually be a thing of the past.  That’s because medical researchers studying how the human body builds muscle and endurance are developing safe and legal substances which can increase the body’s ability to build muscle, without the health risks associated with steroids.

One of the most interesting fields of research surrounds a naturally occurring chemical compound called nitric oxide. Nitric oxide is a vasodilator, which means it helps move oxygen to the muscles when they need it most. Increased nitric oxide in the blood stream signals the blood vessel walls to relax, which allows more blood to flow to the body’s muscles, thus delivering more oxygen and nutrients throughout the body.

It’s been shown to lead to:

  • Drastic Muscle Gains
  • Increased Blood Flow and Oxygen Delivery
  • Boosted Strength, Endurance, and Power
  • Support for Your Immune System
  • Immediate Results
  • Total Body Transformation

While the body naturally increases nitric oxide during workouts, it’s only a limited amount and researchers have been focused on artificially increasing your nitric oxide levels.

One of the most successful products that has emerged from this research is called Factor 2.  It uses “arginines,” special amino acids specifically linked to nitric oxide production to significantly increase oxygen and nutrient flow to the muscles during workouts.  As a result, it can safely spark powerful muscle growth, muscle definition, and strength.

Factor 2 produces noticeable results by maximizing your muscle gains as you power through your workouts and within a few weeks, users are starting to notice additional muscle definition and strength.

Factor 2 is now the recognized leader in nitric oxide stimulation and legal, safe muscle and strength enhancement.  It was Bodybuilding.com’s Best New Brand of the Year (2011) and pro athletes are taking note.

Athletes like professional football player Vernon Davis have discovered the dramatic benefits of using a nitric oxide supplement. Davis has been an advocate of Factor 2 since first taking it, telling his teammates in San Francisco, “Factor 2 has proven results. I believe in results.”

Addiction Treatment

Effective Addiction Treatment

JANE E. BRODY | February 4, 2013 | The New York Time

Countless people addicted to drugs, alcohol or both have managed to get clean and stay clean with the help of organizations like Alcoholics Anonymous or the thousands of residential and outpatient clinics devoted to treating addiction.

But if you have failed one or more times to achieve lasting sobriety after rehab, perhaps after spending tens of thousands of dollars, you’re not alone. And chances are, it’s not your fault.

Of the 23.5 million teenagers and adults addicted to alcohol or drugs, only about 1 in 10 gets treatment, which too often fails to keep them drug-free. Many of these programs fail to use proven methods to deal with the factors that underlie addiction and set off relapse.

According to recent examinations of treatment programs, most are rooted in outdated methods rather than newer approaches shown in scientific studies to be more effective in helping people achieve and maintain addiction-free lives. People typically do more research when shopping for a new car than when seeking treatment for addiction.

A groundbreaking report published last year by the National Center on Addiction and Substance Abuse at Columbia University concluded that “the vast majority of people in need of addiction treatment do not receive anything that approximates evidence-based care.” The report added, “Only a small fraction of individuals receive interventions or treatment consistent with scientific knowledge about what works.”

The Columbia report found that most addiction treatment providers are not medical professionals and are not equipped with the knowledge, skills or credentials needed to provide the full range of evidence-based services, including medication and psychosocial therapy. The authors suggested that such insufficient care could be considered “a form of medical malpractice.”

The failings of many treatment programs — and the comprehensive therapies that have been scientifically validated but remain vastly underused — are described in an eye-opening new book, “Inside Rehab,” by Anne M. Fletcher, a science writer whose previous books include the highly acclaimed “Sober for Good.”

“There are exceptions, but of the many thousands of treatment programs out there, most use exactly the same kind of treatment you would have received in 1950, not modern scientific approaches,” A. Thomas McLellan, co-founder of the Treatment Research Institute in Philadelphia, told Ms. Fletcher.

Ms. Fletcher’s book, replete with the experiences of treated addicts, offers myriad suggestions to help patients find addiction treatments with the highest probability of success.

Often, Ms. Fletcher found, low-cost, publicly funded clinics have better-qualified therapists and better outcomes than the high-end residential centers typically used by celebrities like Britney Spears and Lindsay Lohan. Indeed, their revolving-door experiences with treatment helped prompt Ms. Fletcher’s exhaustive exploration in the first place.

In an interview, Ms. Fletcher said she wanted to inform consumers “about science-based practices that should form the basis of addiction treatment” and explode some of the myths surrounding it.

One such myth is the belief that most addicts need to go to a rehab center.

“The truth is that most people recover (1) completely on their own, (2) by attending self-help groups, and/or (3) by seeing a counselor or therapist individually,” she wrote.

Contrary to the 30-day stint typical of inpatient rehab, “people with serious substance abuse disorders commonly require care for months or even years,” she wrote. “The short-term fix mentality partially explains why so many people go back to their old habits.”

Dr. Mark Willenbring, a former director of treatment and recovery research at the National Institute for Alcohol Abuse and Alcoholism, said in an interview, “You don’t treat a chronic illness for four weeks and then send the patient to a support group. People with a chronic form of addiction need multimodal treatment that is individualized and offered continuously or intermittently for as long as they need it.”

Dr. Willenbring now practices in St. Paul, where he is creating a clinic called Alltyr “to serve as a model to demonstrate what comprehensive 21st century treatment should look like.”

“While some people are helped by one intensive round of treatment, the majority of addicts continue to need services,” Dr. Willenbring said. He cited the case of a 43-year-old woman “who has been in and out of rehab 42 times” because she never got the full range of medical and support services she needed.

Dr. Willenbring is especially distressed about patients who are treated for opioid addiction, then relapse in part because they are not given maintenance therapy with the drug Suboxone.

“We have some pretty good drugs to help people with addiction problems, but doctors don’t know how to use them,” he said. “The 12-step community doesn’t want to use relapse-prevention medication because they view it as a crutch.”

Before committing to a treatment program, Ms. Fletcher urges prospective clients or their families to do their homework. The first step, she said, is to get an independent assessment of the need for treatment, as well as the kind of treatment needed, by an expert who is not affiliated with the program you are considering.

Check on the credentials of the program’s personnel, who should have “at least a master’s degree,” Ms. Fletcher said. If the therapist is a physician, he or she should be certified by the American Board of Addiction Medicine.

Does the facility’s approach to treatment fit with your beliefs and values? If a 12-step program like A.A. is not right for you, don’t choose it just because it’s the best known approach.

Meet with the therapist who will treat you and ask what your treatment plan will be. “It should be more than movies, lectures or three-hour classes three times a week,” Ms. Fletcher said. “You should be treated by a licensed addiction counselor who will see you one-on-one. Treatment should be individualized. One size does not fit all.”

Find out if you will receive therapy for any underlying condition, like depression, or a social problem that could sabotage recovery. The National Institute on Drug Abuse states in its Principles of Drug Addiction Treatment, “To be effective, treatment must address the individual’s drug abuse and any associated medical, psychological, social, vocational, and legal problems.”

Look for programs using research-validated techniques, like cognitive behavioral therapy, which helps addicts recognize what prompts them to use drugs or alcohol, and learn to redirect their thoughts and reactions away from the abused substance.

Other validated treatment methods include Community Reinforcement and Family Training, or Craft, an approach developed by Robert J. Meyers and described in his book, “Get Your Loved One Sober,” with co-author Brenda L. Wolfe. It helps addicts adopt a lifestyle more rewarding than one filled with drugs and alcohol.

Bioartificial

A First: Organs Tailor-Made With Body’s Own Cells

By HENRY FOUNTAIN

Published: September 15, 2012 | The New York Times

STOCKHOLM — Andemariam Beyene sat by the hospital window, the low Arctic sun on his face, and talked about the time he thought he would die.

Two and a half years ago doctors in Iceland, where Mr. Beyene was studying to be an engineer, discovered a golf-ball-size tumor growing into his windpipe. Despite surgery and radiation, it kept growing. In the spring of 2011, when Mr. Beyene came to Sweden to see another doctor, he was practically out of options. “I was almost dead,” he said. “There was suffering. A lot of suffering.”

But the doctor, Paolo Macchiarini, at the Karolinska Institute here, had a radical idea. He wanted to make Mr. Beyene a new windpipe, out of plastic and his own cells.

Implanting such a “bioartificial” organ would be a first-of-its-kind procedure for the field of regenerative medicine, which for decades has been promising a future of ready-made replacement organs — livers, kidneys, even hearts — built in the laboratory.

For the most part that future has remained a science-fiction fantasy. Now, however, researchers like Dr. Macchiarini are building organs with a different approach, using the body’s cells and letting the body itself do most of the work.

“The human body is so beautiful, I’m convinced we must use it in the most proper way,” said Dr. Macchiarini, a surgeon who runs a laboratory that is a leader in the field, also called tissue engineering.

So far, only a few organs have been made and transplanted, and they are relatively simple, hollow ones — like bladders and Mr. Beyene’s windpipe, which was implanted in June 2011. But scientists around the world are using similar techniques with the goal of building more complex organs. At Wake Forest University in North Carolina, for example, where the bladders were developed, researchers are working on kidneys, livers and more. Labs in China and the Netherlands are among many working on blood vessels.

The work of these new body builders is far different from the efforts that produced artificial hearts decades ago. Those devices, which are still used temporarily by some patients awaiting transplants, are sophisticated machines, but in the end they are only that: machines.

Tissue engineers aim to produce something that is more human. They want to make organs with the cells, blood vessels and nerves to become a living, functioning part of the body. Some, like Dr. Macchiarini, want to go even further — to harness the body’s repair mechanisms so that it can remake a damaged organ on its own.

Researchers are making use of advances in knowledge of stem cells, basic cells that can be transformed into types that are specific to tissues like liver or lung. They are learning more about what they call scaffolds, compounds that act like mortar to hold cells in their proper place and that also play a major role in how cells are recruited for tissue repair.

Tissue engineers caution that the work they are doing is experimental and costly, and that the creation of complex organs is still a long way off. But they are increasingly optimistic about the possibilities.

“Over 27 years, I’ve become more convinced that this is doable,” said Dr. Joseph P. Vacanti, a director of the Laboratory for Tissue Engineering and Organ Fabrication at Massachusetts General Hospital and a pioneer in the field.

In Mr. Beyene’s case, an exact copy of his windpipe was made from a porous, fibrous plastic, which was then seeded with stem cells harvested from his bone marrow. After just a day and a half in a bioreactor — a kind of incubator in which the windpipe was spun, rotisserie-style, in a nutrient solution — the implant was stitched into Mr. Beyene, replacing his cancerous windpipe.

It was such a seemingly wild scheme that Mr. Beyene had his doubts when Dr. Macchiarini first proposed it.

“I told him, I prefer to live three years and then die,” he said. “I almost refused. It had only been done in pigs. But he convinced me in a very scientific way.”

Now, 15 months after the operation, Mr. Beyene, 39, who is from Eritrea, is tumor-free and breathing normally. He is back in Iceland with his wife and two small children, including a 1-year-old boy whom he had thought he would never get to know. In Stockholm earlier this year for a follow-up visit, he showed the long vertical scar on his chest and spoke quietly in English, the raspiness of his voice a leftover from radiation therapy.

His strength was improving every day, he said, and he could even run a little.

“Things are good,” Mr. Beyene said. “Life is much better.”

Imitating Nature

To make an organ, it helps to know how nature does it.

That is why Philipp Jungebluth, a researcher in Dr. Macchiarini’s lab, had mounted a heart and a pair of lungs inside a glass jar on a workbench and connected them by tubing to another jar containing a detergent-like liquid. The organs, fresh from a sacrificed rat, had slowly turned pale as the detergent dripped through and out of them, carrying away their living cells. After three days the cells were gone, leaving a glistening mass that retained the basic shape of the organs.

These were the heart and lungs’ natural scaffolds, or extracellular matrix — intricate three-dimensional webs of fibrous proteins and other compounds that keep the various kinds of cells in their proper positions and help them communicate.

Labs around the world are now experimenting with scaffolds. In some cases the goal is to use the natural scaffolds themselves to build new organs — to take a donor lung, for example, strip all its cells and reseed it with a patient’s own cells. Why not use what nature has perfected, this line of thinking goes, rather than try to replicate it in a synthetic scaffold?

Dr. Macchiarini and his team tried this beginning in 2008, successfully implanting reseeded windpipes from cadavers in about a dozen patients, most of whom are now living normal lives. Because the donor’s own cells are removed, this approach all but eliminates a major problem of transplants: the risk that foreign tissue will be rejected by the recipient. But it does not solve several other problems that may be just as troublesome. A donated windpipe may not be the right size; it has to be stripped of its cells and reseeded while the recipient waits; and the procedure still requires donor organs, which are in short supply.

So for Mr. Beyene, the decision was made to produce a scaffold out of plastic. But all the work with natural windpipes proved useful. “We learned so much, starting from zero,” Dr. Macchiarini said. “We could have never done the artificial transplant without the past experience.”

Made to Order

Mr. Beyene’s synthetic scaffold was fabricated by scientists at University College London, using scans of his natural windpipe as a template. It was an exquisite piece of polymer engineering, tailor-made to fit his chest.

But it was still just a lifeless piece of porous plastic. To become a working organ, the tiny spaces in the plastic needed to be filled with cells that would eventually function together as tissue. Not just any cells would do; Dr. Macchiarini and his team would start with stem cells.

To ensure that the organ would not be rejected, the cells had to come from Mr. Beyene himself, which also bypasses the kind of ethical issues that have arisen over the use of embryonic stem cells. Mr. Beyene’s stem cells were obtained from his bone marrow. The cells were placed in nutrient solution and then dripped by pipette over the scaffold. It was like basting a turkey.

Human stem cells are part of the body’s system for building and repairing itself. They begin as a blank slate, but are able to become specialized cells specific to particular tissues or organs like the windpipe. In recent years, scientists have made great advances in understanding how stem cells can differentiate in this way.

The Stockholm team was hoping that with the help of stem-cell-stimulating drugs, the marrow cells placed on the windpipe would start to become the right kinds of cells on both the inside and outside of the organ. But Dr. Macchiarini does not think the process worked quite as planned. “I’m convinced that the cells we are putting in the bioreactor after two or three days are gone,” he said. But as they die they release chemicals that signal the body to send more stem cells from the bone marrow through the bloodstream to the site, aiding the regenerative process.

Or at least that is what Dr. Macchiarini thinks happened. “We are far away from understanding this process,” he said. “Far, far away.”

‘If It Bleeds, It Lives’

If you cannot cough, you’re dead.

That sums up one of the important functions of the windpipe: keeping bacteria and other particles in the air out of the lungs, where they could cause potentially fatal infections. A normal windpipe is lined with specialized cells, including some that produce mucus that can trap the particles. Coughing then brings the mucus up and out.

So one test of a tissue-engineered windpipe is whether it contains these specialized cells. In Dr. Macchiarini’s earlier work involving donor windpipes, he had seeded the inside with similar cells taken from the recipient’s nose. But with Mr. Beyene, Dr. Macchiarini was counting on stem cells to differentiate into these other kinds of cells, generating a lining for the windpipe.

In November, five months after the surgery, Mr. Beyene’s windpipe was found to be partly lined with the specialized cells. And in the later follow-up visit, Dr. Macchiarini noted that the lining was still thriving, with no sign of infection. “And he is able to cough,” Dr. Macchiarini said.

If the cells are surviving, that means the windpipe is developing a complex network of tiny blood vessels through the same regenerative process that produced the specialized cells. All tissues must have such a network so that every cell can get oxygen and nutrients. But developing one — or ensuring that one develops — is an enormous challenge for tissue engineers.

“From the beginning, our view was that the principal barrier to this was going to be the blood supply,” said Dr. Vacanti, whose laboratory has long worked on developing a tissue-engineered liver, among other organs.

Mr. Beyene’s doctors had one way to be certain that his windpipe was developing a blood vessel network. As part of their follow-up exam, they purposely injured the internal lining slightly.

“If it bleeds, it lives,” Dr. Macchiarini said.

Mr. Beyene’s windpipe bled.

A Quest Continues

Mr. Beyene hopes to return someday to Eritrea and work as a geothermal engineer. But for now he remains in Iceland, to be close to Stockholm for regular follow-up visits.

The windpipe contains only his own cells, so he does not need to take drugs to suppress his immune system to ward off rejection. But the synthetic scaffold, like any foreign material, caused the body to produce scar tissue, which had to be removed. While that is no longer a problem, Mr. Beyene does not know when, or if, he will be able to return home. “They have to say, ‘Things are perfect; you don’t need any more care,’ ” he said.

“Nobody knows. This is the first case.”

Last November, five months after Mr. Beyene’s surgery, Dr. Macchiarini implanted a bioartificial windpipe in another cancer patient, Christopher Lyles. He used an improved plastic scaffold, made up of even smaller fibers for the cells to be embedded in. Mr. Lyles returned home to Maryland in January but died in March. The family did not release the cause of death, but Dr. Macchiarini said that the implant had been functioning well.

Despite that setback, in June Dr. Macchiarini performed similar operations on two patients in Russia. Both have been discharged from the hospital and are doing well, he said.

Dr. Macchiarini is planning even more operations. But there needs to be a less complex and cumbersome solution, he said, beyond procedures that can cost up to half a million dollars.

Because the need for this kind of work is potentially so enormous, “we cannot pretend that we can reseed with the specific cells outside the body,” he said. Instead, he envisions developing even better scaffolds and implanting them without cells, relying on drugs to stimulate the body to send cells to the site.

His ultimate dream is to eliminate even the synthetic scaffold. Instead, drugs would enable the body to rebuild its own scaffold.

“Don’t touch the patient,” Dr. Macchiarini said. “Just use his body to recreate his own organ. It would be fantastic.”

Monday: Using animal scaffolding to get human tissue growing.