Personal Health Care

The Yangtze River dolphin, one of the world's rarest mammals, is no more, a victim of China's breakneck economic growth and competition for food with one of the world's most common large mammals — human beings.

"We can say that the animal is functionally extinct," says August Pfluger, head of the Zurich-based Baiji.org Foundation, which in December co-sponsored a six-week, 2,000-mile (3,500-km) survey of the Yangtze without finding a single remaining member of the critically endangered species. The dolphin, one of only four exclusively freshwater species in the world, may have the unhappy distinction of being the first aquatic mammal to go extinct in more than half a century — and the first large mammal driven into oblivion by environmental degradation.

Nicknamed the "goddess of the Yangtze," and long considered auspicious by fishermen, the pale-colored, human-sized dolphins have always been rare: a 1997 survey recorded only 14 left in the river. (A captive dolphin died of old age in a Chinese zoo in 2002). But Pfluger says human pressure pushed the baiji past the tipping point. "The main reason is overfishing. The Chinese still use unsustainable fishing methods like dynamite. There's still a lot of illegal fishing, so the dolphins were competing with humans for food."

According to Wang Ding, a researcher at the Wuhan Institute of Hydrobiology and a leading expert on the baiji, damming on the river and noise from heavy boat traffic may have disoriented the dolphins, which are mostly blind and search for food in the sandy shallows using sonar. The confused and starving animals may then have wandered into boat propellers. Heavy dredging in shipping channels could also have made it harder for the animals to locate each other and hunt for increasingly scarce fish. "Dredging is a very serious problem," Wang says. "It destroys spawning grounds of fish. There are also too many boats. The baiji depend on their sonar ability to survive."

As top-level predators, dolphins like the baiji are an "indicator species" — bellwethers of the general health of an ecosystem. Their disappearance bodes ill for the Yangtze, which supports more than 400 million people, roughly 6% of the world's total population. Wang says the Yangtze is relatively unpolluted. But untrammeled commerce and massive hydrological projects like the Three Gorges Dam have dramatically altered the river's landscape. With as many as 60 boats per km of river in some areas, the Yangtze already looks less like a river than a highway during rush hour. "Baiji are at the top of the food chain just like human beings," Wang says. "If the river can't support baiji, someday it won't support humans either."

Indeed, baiji aren't the only animal facing extinction. Wang says the finless porpoise, another large cetacean native to the river, has also seen its population plummet because of shipping and hydrological engineering. When Wang surveyed the river in the early 1990s, he found about 1,200 of the porpoises; 15 years later, there were fewer than half that number left. But Wang says it may not be too late to save the species. Galvanized in part by the baiji's disappearance, Chinese scientists are taking aggressive steps to rescue the finless porpoise, including breeding the animals in a lake preserve. In fact, Wang believes it may not even be too late for the baiji: there may be a handful of baiji dolphins left in some isolated backwater of the Yangtze. If they can be located and captured, he says, breeding might yet save their species. Pfluger, however, is not so optimistic. "Maybe one or two are left," he says. "But they don't have any chance to survive."

A recent Australian study will have you thinking twice about waiting for those printouts — not for the sake of the paper, but for your health. In the small study, published in the Aug. 1 issue of Environmental Science and Technology, researchers found that nearly 30% of the 62 printers they tested — including laser printers from Canon, HP, Toshiba and Ricoh — emitted high levels of ultrafine toner particles, which were potentially as hazardous as cigarette smoke. In one Brisbane office, the authors found, the concentration of particulate matter per square inch was five times higher during working hours than nonworking hours, and about 3.5 times higher inside than outside, where a freeway ran 130 yards from the building.

For the new study, Lidia Morawska, a physicist at the Queensland Institute of Technology, and her colleagues analyzed printer emissions in a large open-plan office environment. The good news was that 60% of the printers they tested, including eight HP LaserJet 4050 models, four Ricoh Aficio models and one Toshiba Studio, did not emit any particles. But of the 40% that did, many, such as the HP LaserJet 1320 and 4250 models, were classified as "high-level emitters." Emissions, researchers found, were printer-specific and fluctuated depending on the age of the toner cartridge and the amount of toner a document required. It was unclear exactly what mechanism dispersed the particles into the air, but researchers think it had to do with how laser-printer cartridges access and use dry toner or with the printer's mechanical abrasion, wear and age. It's likely that different printers emit particles in different ways.

HP says, in a statement, that it disagrees with the conclusion of the study and with some of its stronger assertions — and believes there is no link between printer emissions and a public health risk. The study's authors concede that more research is needed before they can make any recommendations about the public's printer-related behavior. This study, says Charles Weschler, a chemist and indoor air pollution expert at the Robert Wood Johnson Medical School, is "very much a first cut."

Though it may be premature to inaugurate the term "office lung," the new study highlights the fact that indoor air pollution can't be taken lightly. "It's important to appreciate that most of the air we breathe — whether in our homes, our cars or our offices — is indoors," says Weschler. The Environmental Protection Agency estimates that 90% of our time is spent indoors. According to Weschler, indoor pollution either seeps in from outside (such as particulate matter from car exhaust, ground-level ozone and noxious gases, like sulfur dioxide, which comes from fuel combustion and factories) or originates inside (tobacco smoke, cooking gas, vapors from paint). In general, concentrations of volatile organic compounds, like cleaning agents and pesticides, can sometimes be 10 times higher indoors than outdoors, says Weschler. With long-term exposure, these types of air pollutants can be linked to allergies and respiratory illness, or worse.

The EPA has not done any recent research on the health effects of printer emissions — Morawska's study is the most extensive to date — but Sharon Worthy of the U.S. Dept. of Labor says "historically laser printers have presented no known hazard in the workplace." But, according to the Washington-based nonprofit Environmental Working Group, which has conducted research on particulate pollution from automobiles, printers release the same type of fine particles that cars do. "What we need are standards up front so that the pollution we're subjected to don't pose health risks," says Jane Houlihan, the nonprofit's vice president for research. "Printers are just one of the many things we're exposed to during the day that are potentially harmful."

Think Americans stuck in airports have to wait a long time for a flight? Try 22 years. That's how long astronaut Barbara Morgan, 55 — who blasted off Wednesday aboard the shuttle Endeavour for a planned 11-day mission — had to cool her heels before she got her first chance to fly.

Chosen as the backup to the original teacher-in-space, Christa McAuliffe, in 1985, Morgan was on site at Cape Canaveral the following year when McAuliffe and her six crewmates perished in the explosion of the shuttle Challenger. The fact that she's now in space is a tribute to her tenacity — to say nothing of her courage — as well as to NASA's often artful ability to include a compelling storyline in what would otherwise be a routine space flight. What it says less about — as is so often the case with the NASA of the last generation — is the value of the shuttles themselves and the current state of the manned space program.

The Teacher in Space program was a creature of NASA's arguably naive, 1980s belief that, with a fleet of sturdy shuttles, space flight could become a wonderfully routine thing. Former Utah Senator Jake Garn snagged himself a seat on one flight — never mind that he spent much of the mission so violently space sick that NASA wags informally added a whole new category, labeled "Garn," to the sliding scale used for diagnosing nausea in orbit. Then Congressman (now Senator) Bill Nelson of Florida spent six days in space aboard the shuttle Columbia in January of 1986, the same month Challenger blew up, causing NASA to decide that maybe space flight was a risky enough job that it indeed ought best be left to the professionals.

Morgan nonetheless stayed with the agency, serving as a roving ambassador for space flight and remaining, in name at least, a Teacher in Space designee. Under NASA's newer, stricter flight eligibility rules, however, the only way she could ever get her chance to fly would be to quit the teaching profession and become a professional astronaut, relegating kids' education from space to a much more incidental part of her responsibilities. She applied for a slot and in 1998 was selected; she is now flying as a mission specialist, responsible for operating the robotic arm of both the shuttle and the International Space Station (ISS), with which the crew will be docking.

Sounds like a success story, and in some ways it is. But in the service of what? This is the 119th flight of a space shuttle, the 20th for Endeavour and the 22nd overall to the ISS, a still-growing orbiting outpost that is more or less the only reason any of the shuttles fly anymore. The Endeavour crew will be delivering a two-ton truss segment that will help hold solar arrays and will require three risky spacewalks to install. If the ISS were doing good science at an arguably reasonable price, those risks would be worth taking. But it's doing almost no science at all at an exorbitant price — an estimated $100 billion a year — and will have no shuttles left to service it in 2010 when the shuttle fleet is scheduled to retire. NASA has been promising big payoffs from the ISS — advances in biomedical research, for example, and in materials manufacturing — since President Ronald Reagan first proposed it in 1984, and has never been able to deliver. Meanwhile, the shuttle Columbia claimed the lives of another seven astronauts in 2003, a disaster Morgan was once again on hand to witness, this time as capsule communicator, in Mission Control.

Yesterday's launch included plenty of respectful grace notes. Sixty of the 114 candidates for the Teacher in Space slot in 1985 were at the liftoff, as were a number of relatives of the astronauts lost in the 1986 explosion. NASA was almost defensive in insisting that Endeavour is a sound ship, pointing out that in the nearly five years since it last flew it's undergone improvements so extensive as to leave it almost unrecognizable. "It's like a new space shuttle," shuttle program manager N. Wayne Hale told a news conference.

The astronauts seemed to feel the need to argue for the mission too. "This is serious business we're in here," shuttle commander Scott Kelly radioed shortly before liftoff, as if spacewatchers needed to be reminded of that fact.

Morgan, meantime, will fulfill McAuliffe's legacy, if in a slightly new capacity. No longer a Teacher in Space, but now an "Educator Astronaut," she will teach at least one live lesson from orbit, and up to two more if the mission is extended from 11 to 14 days, as it might be. She is also carrying a cargo of 10 million cinnamon basil seeds (a figure she playfully rounds up to "a kazillion,"), which will be distributed to schoolchildren to grow post-flight, so that they can observe any anomalies that might be attributable to the stint in weightlessness.

All of these things are what educators call teachable moments — a valuable and elusive commodity in the profession that only the best teachers and students know how to exploit fully. The folks at NASA have had two tragic teachable moments of their own — in 1986 and 2003. So far, they don't seem to have learned much.

It's not every day that scientists uncover an unexpected new role for an old, familiar body part. That's why a paper published in the current issue of Cell is generating so much buzz. A team led by Dr. Gerard Karsenty, chairman of the department of genetics and development at Columbia University Medical Center, found that the skeleton plays a powerful role in the regulation of blood sugar and fat deposits. The discovery, made through an elegant series of experiments in mice, could have important implications for treating and preventing type 2 diabetes and obesity — two conditions that are exploding around the globe.

One tends to think of the bones as inert, calcified structures, but they are, in fact, active tissues that constantly renew themselves. Cells called osteoblasts continually build new bone, while osteoclasts destroy old bone. What the new research shows is that the bones also act as a kind of endocrine organ. They release a hormone called osteocalcin that not only acts locally to influence bone formation, but also increases the production of insulin in the pancreas, raises the body's sensitivity to insulin and reduces stores of fat.

No one had any idea it played this role, says Dr. Saul Malozowski, a senior endocrinologist at the National Institute of Diabetes and Digestive and Kidney Disorders. "The skeleton used to be thought of as just a structural support system. This opens the door to a new way of seeing the bones." The finding parallels discoveries in the 1990s about the metabolic activities of fat — another body tissue that was once seen as inert.

Karsenty became intrigued by the relationship between fat and bone after showing in 2002 how leptin, a hormone secreted by fat cells, influences bone formation. Leptin is best known as a regulator of body weight and appetite. Karsenty reasoned that if fat influences bone, then the reverse must be true. And, he says, there was another clue to the relationship: "We were using the observation that obese people are [relatively] protected from osteoporosis."

In some ways it's logical that bone and fat tissue would talk to each other. "Obviously there does need to be some coordination between skeletal growth and body mass," says C. Ronald Kahn, director of the Joslin Diabetes Center at Harvard. "If you carry around extra weight, your bones need to hold up under the extra pressure, so it's not surprising that your bones have a sense of body fat."

But no one suspected just how powerful a role the bones play in so fundamental an activity as regulating sugar. Over a period of three years, Karsenty's team conducted a series of experiments with eight strains of mice, including some genetically altered to lack osteocalcin and some engineered to overeat. He found that osteocalcin significantly impacts how the body handles glucose, its primary fuel, in three ways: by raising the number of insulin-producing beta cells in the pancreas, by directly boosting the output of those cells, and by raising the body's sensitivity to insulin.

Finding a substance that increases beta cells, says Karsenty, "is a holy grail for diabetes research. If what's true for mice proves true for humans, "then we have inside us a hormone that does precisely this." In mice that are programmed to overeat and mice that are fed fatty diets, high levels of osteocalcin prevented both obesity and diabetes. Karsenty is now examining whether giving diabetic mice osteocalcin will reverse the disease.

Exactly what this means for people remains to be seen. Researchers have known that people with diabetes tend to have low levels of osteocalcin, but until now no one understood the significance. "This will open up a lot of new avenues for investigation," says Kahn.

Aug. 10, 2007 -- Looking for a safe substitute for cigarettes? Smokeless tobacco isn't the way to go, according to a new report.       

The report shows that smokeless tobacco may be as bad -- or worse -- than cigarettes, in terms of exposing users to certain cancer-causing chemicals.

"Our results raise serious questions about the strategy of using smokeless tobacco as a substitute for cigarette smoking. Long-term nicotine replacement therapy may be a better option," write the researchers, who included the University of Minnesota's Steven Hecht, PhD.

"This study lends evidence to support the notion that oral use of tobacco actually provides a more efficient means for delivering certain carcinogens into the body through the bloodstream, although cigarette smoke includes a host of carcinogenic products that aren't a major factor in smokeless tobacco," Hecht says in a news release.

Smokeless Tobacco vs. Cigarettes

Data came from six studies that together included 420 smokers and 182 smokeless tobacco users, all of whom were trying to cut down on their tobacco use.

Hecht's team compared levels of certain cancer-causing chemicals detected in the participants' urine samples.

Levels of those chemicals from the smokeless tobacco users were equal to or higher than the levels from the cigarette smokers.

The researchers say that while "there is no doubt that the risk for lung cancer is greater in smokers than in smokeless tobacco users," smokeless tobacco isn't harmless and can cause oral cancer.

The report didn't include details about the participants' medical history. The findings appear in the August edition of the journal Cancer Epidemiology, Biomarkers & Prevention.

SOURCES: Hecht, S. Cancer Epidemiology, Biomarkers & Prevention, August 2007; vol 16: pp 1567-1572. News release, American Association for Cancer Research.