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How Tibetans Enjoy the High Life

The secret is in the blood, and broader arteries to carry it
Science Image: tibetans

HIGH LIFE:  Tibetans cope with daily life in the oxygen-poor air at high altitude by pumping blood at twice the rate of lowlanders through broader blood vessels.

The people of the Tibetan Plateau survive and thrive on the roof of the world, a region averaging 14,763 feet (4,500 meters), or nearly three miles, above sea level. The air at that elevation is not the rich soup of oxygen that humans enjoy at lower elevations. Instead, as many would-be mountain climbers have discovered to their chagrin, it is difficult to get enough of the life-enabling element into their lungs and blood as they ascend, which often results in debilitating symptoms including nausea and dizziness, and can even be fatal. According to new research, Tibetans avoid altitude sickness because they have broader arteries and capillaries delivering oxygen to their muscles and organs.

"At the same time that [Tibetans] are extremely hypoxic at high altitude, they consume the same amount of oxygen that we do at sea level," says anthropologist Cynthia Beall of Case Western Reserve University in Cleveland. "One of the ways they do that is to have very high blood flow—delivering blood to tissue at twice the rate that we are."

The Tibetans increase their blood flow by producing prodigious amounts of
nitric oxide in the linings of the blood vessels. This gas diffuses into the blood and forms nitrite and nitrate, which cause the arteries and capillaries to expand and deliver oxygen-bearing blood to the rest of the body more rapidly than normal. By measuring blood flow in the forearm, Beall and her colleagues report today in Proceedings of the National Academy of Sciences that 88 Tibetan men and women move twice as much blood as 50 Clevelanders, the latter of whom reside a mere 675 feet (205 meters) above sea level. Also, the nitric oxide by-products circulating in Tibetan blood are 10 times greater.

In fact, the Tibetan levels of these nitrites and nitrates are higher than those in patients suffering from a bacterial blood infection—septic shock—and the blood flows are typical of people suffering from high blood pressure. Yet, they have no ill effects in Tibetans. "We don't see an increase in vascular resistance," Beall says. The Tibetans also appear to have higher levels of antioxidants in their bodies, perhaps to help reduce the risk of putting so much nitric oxide—a free radical—into their bloodstreams.

Tibetans breathe a lot, too, averaging more breaths per minute than lowlanders or even their peers in other highland regions, such as the Andes of South America, the latter of whom boast larger lungs than the average human. Also, giving Tibetans pure oxygen actually slows their heart rates by 16 percent. But these scientists say that Tibetans' ability to produce higher levels of nitric oxide is the key to their ability to thrive among the world's tallest peaks.

That raises the question of whether this is evidence of evolutionary functional adaptation in humans. "You have to identify the gene and identify the gene variants that are different," Beall notes. "But it sure seems like a reasonable hypothesis at the moment."

The Tibetans have lived for an estimated 20,000 years on the plateau that bears their name and, in addition to conquering Mount Everest—along with other mountains that number among the planet's highest peaks—on a regular basis, they have managed to build and sustain great societies under challenging conditions. The secret to that success may be encoded in their genes. "This is an example of adaptation to high-altitude hypoxia," Beall says. "Tibetans know they are special because they live at high altitude without getting sick."

PR
Warming Revives Flora and Fauna in Greenland 

 

Winter now comes later to Greenland, meaning more boat travel as fjords, like this one in Narsarsuaq, freeze later and less often. 

NARSARSUAQ, Greenland — A strange thing is happening at the edge of Poul Bjerge’s forest, a place so minute and unexpected that it brings to mind the teeny plot of land Woody Allen’s father carries around in the film “Love and Death.”

Hans Gronborg, a Danish horticulturist, picked cauliflower at Upernaviarsuk, an agricultural research station near Qaqortoq.

Its four oldest trees — in fact, the four oldest pine trees in Greenland, named Rosenvinge’s trees after the Dutch botanist who planted them in a mad experiment in 1893 — are waking up. After lapsing into stately, sleepy old age, they are exhibiting new sprinklings of green at their tops, as if someone had glued on fresh needles.

“The old ones, they’re having a second youth,” said Mr. Bjerge, 78, who has watched the forest, called Qanasiassat, come to life, in fits and starts, since planting most of the trees in it 50 years ago. He beamed like a proud grandson. “They’re growing again.”

When using the words “growing” in connection with Greenland in the same sentence, it is important to remember that although Greenland is the size of Europe, it has only nine conifer forests like Mr. Bjerge’s, all of them cultivated. It has only 51 farms. (They are all sheep farms, although one man is trying to raise cattle. He has 22 cows.) Except for potatoes, the only vegetables most Greenlanders ever eat — to the extent that they eat vegetables at all — are imported, mostly from Denmark.

But now that the climate is warming, it is not just old trees that are growing. A Greenlandic supermarket is stocking locally grown cauliflower, broccoli and cabbage this year for the first time. Eight sheep farmers are growing potatoes commercially. Five more are experimenting with vegetables. And Kenneth Hoeg, the region’s chief agriculture adviser, says he does not see why southern Greenland cannot eventually be full of vegetable farms and viable forests.

“If it gets warmer, a large part of southern Greenland could be like this,” Mr. Hoeg said, walking through Qanasiassat, a boat ride from Narsarsuaq, a tiny southern community notable mostly for having an international airport. Two and a half acres near here of imported pines, spruces, larches and firs are plunked in the midst of the scrubby, rocky hillside next to the fjord, as startling as a mirage. “If it gets a little warmer, you could talk about a productive forest with enough wood for logs,” Mr. Hoeg said.

Farther north, Greenland’s great ice sheet, a vast white landscape of 0.695 million square miles covering 80 percent of the island’s land mass, is melting rapidly, alarmingly, with repercussions not only for the traditional way of life on an island of 56,000 people, but also for the rest of the world. The more the ice melts, the higher sea levels will eventually rise.

But here in the subarctic south — a land of icy water, forbidding mountains, rocky hills, shallow soil, sudden winds and isolated communities slipped in, almost apologetically, along a network of glacier-studded fjords, the changes are more subtle and carry more promise.

“The limiting factor for human survival here is temperature, and there’s a lot of benefits with a warmer climate,” Mr. Hoeg said. “We are on the frontier of agriculture, and even a few degrees can make a difference.”

Winter is coming later and leaving earlier. That means there is more time to leave sheep in the mountains, more time to grow crops, more time to work outdoors, more opportunity to travel by boat, since the fjords freeze later and less frequently.

Cod, which prefer warmer waters, have started appearing off the coast again. Ewes are having fatter lambs, and more of them every season. The growing season, such as it is, now lasts roughly from mid-May through mid-September, about three weeks longer than a decade ago. “Now spring is coming earlier, and you can have earlier lambings and longer grazing periods,” said Eenoraq Frederiksen, 68, a sheep farmer whose farm, near Qassiarsuk, is accessible by a harrowing drive across a rudimentary road plowed in the hillside. “Young people now have a lot of possibilities for the future.”

Scattered reports of successful strawberry crops in the odd home garden are heard, although it helps to keep them in perspective. As Hans Gronborg, a Danish horticulturist, put it, laughing, “They know whether they’ve harvested 20 strawberries, or 25.” He works at Upernaviarsuk, an agricultural research station near Qaqortoq, one of the largest towns in the south. Like everywhere else, it is accessible only by boat or helicopter. As a rule, no roads connect Greenland towns.

As if visiting the zoo, people come from all over to gape at the varieties of grass in the fields and to see what is growing here, among other things, 15 strains of potatoes and, for the first time, annual flowers: chrysanthemums, violas, petunias.

Mr. Gronborg plucked a head of cauliflower from its nest of leaves. It had a rich, almost sweet flavor — the result, he explained, of slow growth, long summer days of 20 hours of light, and wide swings in temperature from day to night. “It’s small, but it means you get all that flavor concentrated in one-third the size of a regular cauliflower,” he said.

Mr. Gronborg loaded a dozen trays of vegetables into a motorboat to take them to the supermarket in Qaqortoq. Soon, he said, restaurants will serve Greenlandic vegetables beside Greenlandic lamb and reindeer.

“Greenlanders are hunters, and it takes time to change their way of living and being,” he said. “But I am confident that things can grow in south Greenland.” 

Greenland, a self-governing province of Denmark, was settled by the pugilistic Viking Erik the Red in the 10th century, after his murderous ways got him ejected from Iceland. Legend has it that he called it Greenland as a way to entice others to join him, and, in fact, it was.

It was relatively green then, with forests and fertile soil, and the Vikings grew crops and raised sheep for hundreds of years. But temperatures dropped precipitously in the so-called Little Ice Age, which began in the 16th century, the Norse settlers died out and agriculture was no longer possible.

Climate is a delicate matter in a place like this. A degree more of warmth here, an inch less of rain there; these can have serious repercussions for a farmer eking out a living raising sheep on the harsh terrain. But while temperatures here in the south dipped in the 1980s, they have risen steadily since. Between 1961 and 1990, the average annual temperature was 33 degrees; in 2006, it was 35 degrees, according to the Danish Meteorological Institute. 

Pushing Five O’Clock Shadow Back a Few Hours
 

HURTS SO BAD
A few of the products that may or may not help slow the growth of a beard, or at least ease some of the razor burn and redness that plague many men.

“It’s a wonderful irony,” said Eric Malka, a founder of the Art of Shaving, a national chain of barbershops. “Young people can’t wait to do adult things, and see shaving as a rite of passage into manhood. Then we spend the rest of our lives trying to avoid it.”

At 29, Anthony Pilowa is already fed up. “It’s a repetitive, daily frustration,” said Mr. Pilowa, a manager of clinical trials at Wyeth Pharmaceuticals. “I really look forward to the weekends when I can have a couple of days without the shaving.”

What man doesn’t? Shaving has its perils: ingrown hairs, irritation, razor burn and bumps. And like death and taxes, facial-hair growth is unavoidable for men. But that hasn’t stopped companies like Clarins and Lab Series from offering ways to delay the inevitable.

In the last two years, a bevy of after-shaves and night treatments that promise to slow the appearance of stubble have hit the market. They don’t help shavers kick the habit, just reduce how often their four-blade must be used.

Some hair retardants have sold well. Sales of Clarins Men Skin Difference, which promises to slow beard growth and improve skin texture, have increased by 10 percent since its January debut, and the oil now ranks third among the company’s 16 men’s products. Another beard-slower, Origins for Men Fire Fighter Plus after-shave, accounted for an 11.4 percent boost in sales of the Origins nine-product male line in 2007.

Others have yet to find their footing. Released in 2005, Clinique Skin Supplies for Men Post-Shave Soother Beard Control Formula still isn’t a top seller, a company spokeswoman said.

Still, many of the hirsute are clamoring for a reprieve. “A number of men come into our stores requesting ways to slow beard growth,” Mr. Malka said.

Three weeks after slathering on Clarins Men Skin Difference, Mr. Pilowa, who suffered from ingrown hairs and prodigious growth, said it improved his skin. “My five o’clock shadow shows up around 10 or 11 at night,” said Mr. Pilowa, who also has fewer ingrown hairs.

Steven Horn, a director of international merchandising for Converse, said Lab Series for Men Triple Benefit Post-Shave Remedy was a face-saver on long overseas flights. “When I land 20 hours later, I don’t look like I need a shave,” Mr. Horn, 36, said. “I used to have to shave again once I reached my hotel and that was irritating to my skin, but now I can just go.”

The products rely on plant extracts that interfere with the growth in the follicles that produce facial hair, manufacturers say. One common ingredient, saw palmetto, an extract of the dwarf palm tree, inhibits the enzyme responsible for converting the hormone testosterone into dihydrotestosterone, which regulates hair growth.

“The funny thing is that saw palmetto actually promotes hair growth on the head,” said Tom Mammone, the executive director of research for Clinique. Blocking the hormone in the follicles on your face can slow hair growth, while having the opposite reaction if applied to the scalp, Mr. Mammone explained.

Palmatine, a plant extract, is another common ingredient in hair-growth delayers. Its exact function is unknown, but product developers like Clarins suggest it slows the division of cells responsible for creating hair.

The new slew of hair-slowing potions don’t impress some dermatologists. “There is a lot of discussion involving these products and little actual scientific research to substantiate the claims,” said Dr. Neil Sadick, a clinical professor of dermatology at Weill Medical College of Cornell University in New York.

“Saw palmetto is a weak enzyme inhibitor, so theoretically it might slow hair growth on the face,” Dr. Sadick said. “But it has never been proven to work that way.”

And palmatine? If in fact it does hamper the division of cells responsible for hair growth, then, Dr. Sadick said, it would be similar to Vaniqa, the only prescription medication of its kind approved by the Food and Drug Administration. (Vaniqa is usually prescribed to women with unwanted facial hair.)

Dr. Bradford Katchen, a cosmetic dermatologist in SoHo, remembers a male patient who applied Vaniqa to his beard and experienced patchy hair growth. “Hair-growth-slowing treatments can’t block 100 percent of the enzyme, so a guy’s facial hair wouldn’t have a uniform look,” he said.

Patchiness aside, there’s little harm in men using these products, said Dr. Debra Jaliman, an assistant clinical professor of dermatology at Mount Sinai School of Medicine. “It’s an inexpensive technology compared to other treatments like laser hair removal, and seemingly benign,” she said. “Guys with sensitive skin, thick beards or just those who don’t like to shave a lot might like it.”

Bacteria species may help ethanol output

Scientists say a new bacteria species discovered in Yellowstone's thermal pools could improve the use of bacteria to produce ethanol.

Researchers found the bacteria in Octopus and Mushroom springs as well as in Green Finger Pool. The bacteria thrive in hot water, growing best between 120 and 150 degrees.

The discovery is rare because the bacterium is photosynthesizing, meaning it produces energy from sunlight. Scientists have discovered just three similar bacteria species within the past century, according to Don Bryant, a professor of biotechnology, biochemistry and molecular biology at Penn State University and leader of the research team.

Bryant published the discovery in the July issue of Science.

"Among microbiologists, this would be considered a big deal," Bryant said.

He speculated that the bacteria could be used by researchers who are looking for new ways to use bacteria to produce ethanol, which can be burned like gasoline.

The bacteria, he said, likely obtain carbon not from the atmosphere, but by removing the waste of other bacteria. That could help other types of bacteria grow much more quickly.

"It's really not all that complicated to get a little more bang for your buck," he said.

The researchers discovered the species by examining DNA information gathered by David Ward, a Montana State University researcher who has spent decades investigating the mats of bacteria common in Yellowstone's thermal features. Such bacteria are called thermophilic for their ability to thrive where it's hot.

Bryant said he sifted through hundreds of DNA sequences on a computer.

"We're looking for signatures of genes that are distinctly different than anything that's known," he said.

After examining the DNA of the new bacteria, called Chloracidobacterium termophilum, Bryant then had to prove that the bacterium existed.

"A virtual organism, something that we had found only on a computer, is not something that can be publishable in Science," he said.

"Most of the next year went in to trying to isolate the organism, finding out what properties it had, and demonstrating that it actually can convert light energy into chemical energy. It's not whether you've got some genes, it's how you're using them."

He eventually was able to isolate the bacterium.

"We got the proof that the organism that was growing on light energy," he said. "We grew the organism repeatedly in light and dark. If you grow it in the dark, it grows much more slowly, if at all. If you grow it in light, it grows much faster."

Exterminate! Exterminate!New malaria vaccines—and a pep talk from the man who is paying for some of them—are raising the idea that malaria might be eliminated once and for all


Getty Images

“WE'VE made vaccines from pus and poop, we make them now using eggs—so why not make them in live mosquitoes?” So says Stefan Kappe, a researcher at the Seattle Biomedical Research Institute. To prove the point, his team is breeding millions of Anopheles mosquitoes (pictured above) and infecting them with malaria-causing parasites.

Not any old parasites, either. Those he uses have had some of their genes knocked out to stop them breeding in humans. Their destiny, like that of the “attenuated” viral strains grown in eggs, is to form part of a vaccine. 

Once the parasites have had time to breed in the mosquitoes, the insects are killed and dissected under a microscope. The gold inside them is their salivary glands, the parts richest in parasites. These are extracted, processed and turned into what Dr Kappe hopes will become a successful vaccine. By injecting this vaccine of pared-down parasites into uninfected individuals, he intends to provoke an immune response to malaria that will be strong enough to kill a real infection before it gets going.

Provoking such a response is, of course, the idea behind any vaccine, and there are various ways of doing it. Dr Kappe's looks promising in the laboratory, but has yet to undergo clinical trials. Another method, however, has been on trial for several years by Pedro Alonso of the Barcelona Centre for International Health Research. This week saw the publication in the Lancet of the latest results from those trials. They look very promising indeed.

Surface and depth

The vaccine created by Dr Alonso and his colleagues has been tested on infants aged under five months in a region of Mozambique where the disease is endemic. It did not provide complete protection, but the infection rate observed over the course of the subsequent six months was 65% lower than in members of a control group, who were given a hepatitis B vaccination instead. And it was also safe—an important consideration, since infants are both the people most vulnerable to malaria and those in whom it is easiest to provoke adverse reactions.

Unlike Dr Kappe's vaccine, this one does not rely on injecting whole, attenuated parasites. Instead, some of the proteins that adorn the parasite's surface have been made in bulk. The vaccine is thus, in effect, all surface. Since the immune system can see only the surface of even a whole parasite, that is the only part it can learn to recognise, so a vaccine consisting of parasite surface and nothing else should be good at stimulating an immune response—and it is.

Dr Alonso's paper, then, is a bit of good news in an area—global health—that is more usually associated with misery. It is not, however, the only optimistic note as far as malaria is concerned. A newish and very effective drug called artemesinin is now being deployed, and the campaign to distribute insecticide-laced bed nets through large parts of Africa is also showing signs of success. A few people are therefore daring to whisper a word that has not been heard much in malaria circles since the 1960s: eradication.

On October 17th, the day Dr Alonso's paper was published, someone dared do more than whisper the word. Bill Gates almost shouted it at a conference on the disease which was organised in Seattle by his foundation. The Gates Foundation helped to finance the trials in Mozambique and Mr Gates used their success to give a rousing speech to the gathered experts, challenging them to raise their sights. Rather than continue with today's strategy of merely controlling malaria, he argued that it is time for the world to aspire to exterminate it altogether.

This is not a new idea. The last attempt to eradicate malaria began in 1955 (coincidentally, the year Mr Gates was born) and relied on a new wonder chemical called DDT to kill the mosquitoes. For a time, it was successful, but then evolution struck back, as natural selection favoured the spread of insecticide-resistant genes. Shortly afterwards, politics struck back, too, as the environmental movement successfully demonised DDT because of the damage it does to many other animals.

Given this history, cynicism about the idea of eradication is understandable. Steven Phillips, chief medical officer of Exxon Mobil, a firm whose African operations are inevitably affected by malaria, argues that eradication is technically impossible and favours emphasis on “bread and butter” disease control. But Regina Rabinovich and Tachi Yamada, the scientists responsible for running the Gates Foundation's anti-malaria effort, argue that eradication was never seriously attempted in Africa in the past. They think that today's money, technologies and political will are strong enough to make eradication a realistic aspiration.

Dr Phillips is right, in the sense that even the finest vaccine cannot do much good if it does not reach villages in endemic areas. However, things change—even in Africa. A report released this week by Unicef, the United Nations Children's Fund, suggests several countries, including Ghana, Tanzania, Benin and Gambia, are making progress in spreading artemesinin and bed nets.

Eradication would not be cheap. A back-of-the-envelope estimate suggests it would cost about $9 billion a year for two or three decades to make and distribute the necessary vaccines, drugs and equipment. But that compares with $3 billion a year indefinitely, merely to contain the problem—not to mention the economic damage done by the disease. Big ideas have to await the right time to be realised. But for malaria that time may be now.

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