Monthly Archives: April 2006

Print me a heart and a set of arteries

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SITTING in a culture dish, a layer of chicken heart cells beats in synchrony. But this muscle layer was not sliced from an intact heart, nor even grown laboriously in the lab. Instead, it was “printed”, using a technology that could be the future of tissue engineering.

Gabor Forgacs, a biophysicist at the University of Missouri in Columbia, described his “bioprinting” technique last week at the Experimental Biology 2006 meeting in San Francisco. It relies on droplets of “bioink”, clumps of cells a few hundred micrometres in diameter, which Forgacs has found behave just like a liquid.

This means that droplets placed next to one another will flow together and fuse, forming layers, rings or other shapes, depending on how they were deposited. To print 3D structures, Forgacs and his colleagues alternate layers of supporting gel, dubbed “biopaper”, with the bioink droplets. To build tubes that could serve as blood vessels, for instance, they lay down successive rings containing muscle and endothelial cells, which line our arteries and veins. “We can print any desired structure, in principle,” Forgacs told the meeting.

New Scientist

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Ancient fossils fill gap in early human evolution

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LONDON (Reuters) – An international team of scientists have discovered 4.1 million year old fossils in eastern Ethiopia that fill a missing gap in human evolution.

The teeth and bones belong to a primitive species of Australopithecus known as Au. anamensis, an ape-man creature that walked on two legs.

The Australopithecus genus is thought to be an ancestor of modern humans. Seven separate species have been named. Au. anamensis is the most primitive.

“This new discovery closes the gap between the fully blown Australopithecines and earlier forms we call Ardipithecus,” said Tim White, a leader of the team from the University of California, Berkeley.

“We now know where Australopithecus came from before 4 million years ago.”

Reuters via Anthropology.net

Found and analyzed by scientists from the United States, Ethiopia, Japan and France, the fossils were unearthed in the Middle Awash area in the Afar desert of eastern Ethiopia.

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All the Pleasures of Alcohol, With No Downsides

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CASUAL drinkers are unlikely to have raised their glass to the news last month that most people who suffer severe alcohol-induced liver disease are social drinkers not alcoholics. Nor to the finding that moderate drinking might not, after all, help prevent heart disease.

There may, however, just be a solution to our drinking woes – one that will allow us to go to a bar and drink as much as we want; get merry, not legless; wake without a hangover; and never have to worry that one of our favourite pastimes may be killing us. It’s a cocktail of drugs that mimics the pleasurable effects of alcohol without the downsides. The idea is only on the drawing board, but there is no scientific reason why it could not be made right now, says psychopharmacologist David Nutt of the University of Bristol in the UK.

NewScientist

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Regrow Your Own

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Stem cell therapy has long captured the limelight as a way to the goal of regenerative medicine, that of repairing the body with its own natural systems. But a few scientists, working in a relatively obscure field, believe another path to regenerative medicine may be as likely to succeed. The less illustrious approach is promising, in their view, because it is the solution that nature itself has developed for repairing damaged limbs or organs in a wide variety of animals.

Many species, notably amphibians and certain fish, can regenerate a wide variety of their body parts. The salamander can regenerate its limbs, its tail, its upper and lower jaws, the lens and the retina of its eye, and its intestine. The zebra fish will regrow fins, scales, spinal cord and part of its heart.

Mammals, too, can renew damaged parts of their body. All can regenerate the liver. Deer regrow their antlers, some at the rate of 2 centimeters a day, said to be the fastest rate of organ growth in animals. In many of these cases, regeneration begins when the mature cells at the site of a wound start to revert to an immature state. The clump of immature cells, known as a blastema, then regrows the missing part, perhaps by tapping into the embryogenesis program that first formed the animal.

If the genes that boot up the zebra fish blastema also exist in people but are not switched on, perhaps some drug might be developed that goads them into action.

NYTimes

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Japan Unveils the Fastest Train in the World

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East Japan Railway Co. unveiled the latest prototype of the next-generation bullet train, code-named “Fastech 360Z,” to the press on Wednesday at its rolling stock laboratory center near Sendai in northern Japan.

The six-car Fastech will aim to log the world’s fastest speed for wheeled trains at 360 kilometers (224 miles) per hour during a normal journey.

In comparison, France’s TGV (Train Grande Vitesse) ordinarily runs at 300 kph. However, the TGV still holds the world record for wheeled trains for hitting 515 kph (320 mph).

PhysOrg

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Lab-Grown Bladders ‘A Milestone’

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US scientists have successfully implanted bladders grown in the laboratory from patients’ own cells into people with bladder disease.

The researchers, from North Carolina’s Wake Forest University, have carried out seven transplants, and in some the organ is working well years later.

BBC

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Study Explains Evolution’s Molecular Advance

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By reconstructing ancient genes from long-extinct animals, scientists have for the first time demonstrated the step-by-step progression of how evolution created a new piece of molecular machinery by reusing and modifying existing parts.

The researchers say the findings, published today in the journal Science, offer a counterargument to doubters of evolution who question how a progression of small changes could produce the intricate mechanisms found in living cells.

“The evolution of complexity is a longstanding issue in evolutionary biology,” said Joseph W. Thornton, professor of biology at the University of Oregon and lead author of the paper. “We wanted to understand how this system evolved at the molecular level. There’s no scientific controversy over whether this system evolved. The question for scientists is how it evolved, and that’s what our study showed.”

NYTimes

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Newly Found Species Fills Evolutionary Gap Between Fish And Land Animals

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Paleontologists have discovered fossils of a species that provides the missing evolutionary link between fish and the first animals that walked out of water onto land about 375 million years ago. The newly found species, Tiktaalik roseae, has a skull, a neck, ribs and parts of the limbs that are similar to four-legged animals known as tetrapods, as well as fish-like features such as a primitive jaw, fins and scales.

Tiktaalik

These fossils, found on Ellesmere Island in Arctic Canada, are the most compelling examples yet of an animal that was at the cusp of the fish-tetrapod transition. The new find is described in two related research articles highlighted on the cover of the April 6, 2006, issue of Nature.

“Tiktaalik blurs the boundary between fish and land-living animal both in terms of its anatomy and its way of life,” said Neil Shubin, professor and chairman of organismal biology at the University of Chicago and co-leader of the project.

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‘Truth Verifier’ for Russian airports

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MOSCOW, April 6 (UPI)—Russia plans to ramp up airport security by introducing lie detector screening for passengers.

The machine, known as the “truth verifier,” could be introduced at Domodedovo Airport this July, The Telegraph reports. Plans call for initial screening of air passengers who seem suspicious, with eventual expansion to all passengers.

Passengers must answer four questions. While the first is only name and address, the second—whether a passenger has ever lied to the authorities—is followed by specific questions about weapons and drugs. Those who fail the test will go to a cubicle for more thorough questioning.

To ensure that everyone goes through the machine, passengers are to remove shoes beforehand and will not get them back until they have passed.

“We can understand that something like this could be uncomfortable for some passengers, but it is a necessary step,” said Vladimir Kornilov, head of information technology at the Moscow airport.

UPI via Fark

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Problems After 40,000 Ecstasy Pills (Kouimtsidis 2005)

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Mr. A, 37 years old, used ecstasy between the ages of 21 and 30. For the first 2 years, he took 5 tablets every weekend, escalating to an average daily use of 3.5 tablets for the next 3 years, and further escalation to an average of 25 tablets daily over the next 4 years. An estimate of lifetime consumption yielded a total intake of more than 40,000 tablets. At the time of his presentation, Mr. A reported current cannabis consumption, together with a previous history of polydrug misuse (i.e., solvents, benzodiazepines, amphetamines, LSD, cocaine, heroin). After three episodes of “collapsing” at parties, Mr. A finally stopped his ecstasy use. For a few months, he felt as if he was still under the influence of ecstasy and suffered several episodes of “tunnel vision.” He eventually developed severe panic attacks, recurrent anxiety, depression, muscle rigidity (particularly at the neck and jaw levels), functional hallucinations, and paranoid ideation. His family and before-drug-use psychiatric history were negative. The Mini-Mental State Exam revealed disorientation to time, poor concentration, and short-term memory difficulties. Decrease in level of cannabis intake led both to disappearance of his paranoid ideas and hallucinations and reduction of his panic attacks, but remaining symptomatology persisted. Administration of the Wechsler Memory Scale (3rd Edition)3 suggested the existence of global memory-function impairment, with no subtest score being above the 10th percentile. Assessment of daily functioning skills identified major behavioral consequences of his memory loss (i.e., repeating activities several times). Although Mr. A was able to fully understand the instructions given, his concentration and attention were so impaired that he was unable to follow the sequence of the tasks required. A structural MRI brain scan revealed no focal cerebral lesions; specifically, both temporal lobes showed normal symmetrical hippocampal areas. The structural areas of the “Dealy-Brion” system were normal. There was no evidence to suggest atrophy. Mr. A was then prescribed olanzapine 10 mg and admitted to a brain-injury unit, where there was some improvement of his memory skills as a result of the use of compensatory strategies.

psychiatryonline

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Bioengineering Professor Hopes to Mimic the Brain on a Chip

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Microchips that function as the brain does or see like our eyes do were once consigned to an unrealized world of flying cars and robot housekeepers. Thanks, in part, to a Stanford researcher, such “neuromorphic” processors are becoming more of a reality.

“We are taking knowledge from neuroscience and using it to build better computers,” said Kwabena Boahen, an associate professor in the Department of Bioengineering who directs a research group tasked with mimicking the functions of the brain’s complex neural system using silicon chips. Boahen hopes his research will lead to small computers that could replace damaged neural tissue or silicon retinas that restore vision. He believes understanding how the brain functions could help make computation more efficient.

“What we’re trying to do now—we’ve come up with ways of modeling neurons and synapses—is to build chips with something like 100,000 neurons on [them] and then build a multiple-chip network that gets up to about 1 million neurons,” Boahen said. “With a network of that size, you can model what the different cortical areas are doing and how they are talking to each other.”

StanfordU

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Vegetarian Diets Cause Major Weight Loss

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A scientific review in April’s Nutrition Reviews shows that a vegetarian diet is highly effective for weight loss. Vegetarian populations tend to be slimmer than meat-eaters, and they experience lower rates of heart disease, diabetes, high blood pressure, and other life-threatening conditions linked to overweight and obesity. The new review, compiling data from 87 previous studies, shows the weight-loss effect does not depend on exercise or calorie-counting, and it occurs at a rate of approximately 1 pound per week.

Rates of obesity in the general population are skyrocketing, while in vegetarians, obesity prevalence ranges from 0 percent to 6 percent, note study authors Susan E. Berkow, Ph.D., C.N.S., and Neal D. Barnard, M.D., of the Physicians Committee for Responsible Medicine (PCRM).

The authors found that the body weight of both male and female vegetarians is, on average, 3 percent to 20 percent lower than that of meat-eaters. Vegetarian and vegan diets have also been put to the test in clinical studies, as the review notes. The best of these clinical studies isolated the effects of diet by keeping exercise constant. The researchers found that a low-fat vegan diet leads to weight loss of about 1 pound per week, even without additional exercise or limits on portion sizes, calories, or carbohydrates.

“Our research reveals that people can enjoy unlimited portions of high-fiber foods such as fruits, vegetables, and whole grains to achieve or maintain a healthy body weight without feeling hungry,” says Dr. Berkow, the lead author.

Science Blog

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Weekly Religious Attendance Nearly as Effective as Statins and Exercise in Extending Life

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In a study comparing the associations between faith and health, a University of Pittsburgh Medical Center (UPMC) physician has shown the improvements in life expectancy of those who attend religious services on a weekly basis to be comparable to those who participate in regular physical exercise and to those who take statin-type medications. These findings are published in the March-April issue of the Journal of the American Board of Family Medicine.

The study uses life expectancy tables to compare the impact of regular exercise, statin therapy and religious attendance, and shows that each accounts for an additional two-to-five years of life, suggesting that the real-world, practical significance of weekly religious attendance is of similar magnitude to this other widely recommended therapy or health behavior.

Science Blog

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In a Wired South Korea, Robots Will Feel Right at Home

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South Korea, the world’s most wired country, is rushing to turn what sounds like science fiction into everyday life. The government, which succeeded in getting broadband Internet into 72 percent of all households in the last half decade, has marshaled an army of scientists and business leaders to make robots full members of society.

By 2007, networked robots that, say, relay messages to parents, teach children English and sing and dance for them when they are bored, are scheduled to enter mass production. Outside the home, they are expected to guide customers at post offices or patrol public areas, searching for intruders and transmitting images to monitoring centers.

If all goes according to plan, robots will be in every South Korean household between 2015 and 2020. That is the prediction, at least, of the Ministry of Information and Communication, which has grouped more than 30 companies, as well as 1,000 scientists from universities and research institutes, under its wing. Some want to move even faster.

“My personal goal is to put a robot in every home by 2010,” said Oh Sang Rok, manager of the ministry’s intelligent service robot project.

NYTimes

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