Motile cilia on airway epithelial cells
Image: SEM by Tom Moninger

The-Scientist.com, July 29, 2009, by Bob Grant  —  Your sense of taste doesn’t end in your mouth: Cilia lining airways leading to the lungs express taste receptors and alter their undulations in the presence of bitter chemicals, says a study published online in the July 23rd edition of Science.

These cilia are linked to signaling pathways that regulate their motility, allowing epithelial tissues in airways to sense toxins or noxious compounds and help protect the lungs.


This is the first paper that shows that motile cilia can have sensory function,” said Gáspár Jékely, a cell and molecular biologist at the Max Planck Institute for Developmental Biology in Tuebingen, Germany, who was not involved in the study. “That’s really quite remarkable that you have structures that move around but are also intimately tied to signaling pathways.”

Primary cilia — relatively immobile cellular extensions that play important roles in sight and olfaction — have long been known to serve in sensory capacities, but motile cilia were thought only to wave (or “beat”), moving mucous through airways and ova down fallopian tubes, for example. Alok Shah, a University of Iowa graduate student in the lab of Michael Welsh and co-first-author on the paper, said that researchers typically thought of primary cilia as “the smart ones” while motile cilia were characterized as the “workhorses” of the cilia universe.

“The motile cilia were thought to be, well, just motile and not much more,” Maxence Nachury, a Stanford molecular and cell biologist who was not involved with the study, told The Scientist.

Shah and his collaborators searched for sensory-related genes in samples of human airway epithelia, the cells that line the trachea and upper bronchi. They found several members of the T2R family, which senses and responds to bitter tastes, lurking in microarray expression data. Using antibodies to specific T2Rs, they singled out four specific receptors localized in cilia protruding from epithelial cells that line airways.

“I was very surprised” by the results, Shah told The Scientist. “When I first saw that, I thought, ‘Oh my God. What are taste receptors doing in the airways?'”

Moreover, the team noticed that the four different T2Rs localized to different parts of a single cilia. “As far as I know, no one has seen different receptors of the same family localizing differentially like that.” Shah said this differential localization may play a role in tweaking sensitivities or signaling pathways.

To nail down the motile cilia’s role in these signaling pathways, Shah subjected cultured airway epithelial tissues to several bitter compounds, including nicotine. “We found a very nice dose dependent increase in intracellular calcium” — the hallmark of cell signaling cascades — “in response to bitter compounds,” Shah noted. This calcium boost was followed by increased rates of ciliary beating.

The taste-sensing abilities of motile cilia could also lead to bitter compound-mimicking drugs that could target motile cilia to increase their beating to clear disrupted airways, as is common in cystic fibrosis. “This is a clear target that could be used to upregulate ciliary beating in the airways,” said Jékely. Conversely, in asthma, where epithelial airway surfaces become inflamed and irritated, drugs targeting motile cilia could quell the inflammation. “If one could modulate the excitation at the surface of these cilia,” said Nachury, “one could really have a way to dampen that reaction.”

Shah, who recently received his PhD and is now shopping for a postdoc position, said that much about the sensory role and molecular mechanisms of motile cilia is yet to be discovered.

Sudipto Roy, a researcher at the Institute of Molecular and Cell Biology in Singapore, agreed. “It will not be too surprising if subsequent research shows that motile cilia act as signaling hubs for many other kinds of sensory pathways,” Roy wrote in an email to The Scientist.

by Gabe Mirkin MD  —  Why are some people skinny, even though they eat large amounts of food, while others become fat? Jeffery Gordon of Washington University in St. Louis thinks it’s because some people have types of bacteria that cause them to absorb more calories from their food.

You have two absorption systems in your body. You absorb most of your food as it passes through your small intestines. Food that is not absorbed in the small intestine goes to your colon. The colon contains a huge colony of bacteria that work to ferment undigested carbohydrates such as soluble fiber into short chain fatty acids and simple sugars that can then be absorbed through the colon walls into the bloodstream. Most people get about ten percent of their total calories from food absorbed through their colons.

Animal studies lead us to the next step. The dominant bacteria in the gut of obese mice are Firmicutes, types of bacteria that have more genes for breaking down the complex starches and fiber. Mice who are thin have more Bacteroidetes in their guts, and these bacteria are not as efficient in breaking down fiber and complex carbohydrates. Transplanting Firmicutes bacteria into the guts of lean mice made them fat.

These researchers also found that fat humans had far more Firmicutes bacteria than thinner ones. They then asked their overweight subjects to go on a low-fat, low-refined- carbohydrate diet for one year. As they lost weight, their bacteria changed to predominantly Bacteroidetes.

Today you may be able to lose weight by changing the composition of your diet in a way that changes the bacteria in your gut so you absorb fewer calories. In the future, you may be able to get a pill that contain primarily Bacteroidetes bacteria, take it daily and watch the pounds melt off because of the change in intestinal bacteria. – www.DrMirkin.com


WebMD.com, July 28, 2009, by Denise Foley  —  Thirty billion a year — that’s about how much Americans spend on slim-down products, many of which don’t even work. A better way to get real weight-loss results? Go grocery shopping. New research points to more than a dozen foods, from beans to beef, that can help you fight hunger, kick your candy addiction, boost your metabolism-and ultimately shed pounds. And some of these superfoods deliver health bonuses too.


1. Eggs. Skip the bagel this morning. Eggs, which are full of protein, will help you feel fuller longer-a lot longer. A multicenter study of 30 overweight or obese women found that those who ate two scrambled eggs (with two slices of toast and a reduced-calorie fruit spread) consumed less for the next 36 hours than women who had a bagel breakfast of equal calories. Other research has shown that protein may also prevent spikes in blood sugar, which can lead to food cravings.

2. Beans. You’ve probably never heard of cholecystokinin, but it’s one of your best weight-loss pals. This digestive hormone is a natural appetite suppressant. So how do you get more cholecystokinin? One way, report researchers at the University of California at Davis, is by eating beans: A study of eight men found that their levels of the hormone (which may work by keeping food in your stomach longer) were twice as high after a meal containing beans than after a low-fiber meal containing rice and dry milk. There’s also some evidence that beans keep blood sugar on an even keel, so you can stave off hunger longer. Heart-health bonus: High-fiber beans can lower your cholesterol.

3. Salad. Do you tend to stuff yourself at meals? Control that calorie intake by starting with a large salad (but hold the creamy dressing). In a study of 42 women at Penn State University, those who ate a big, low-cal salad consumed 12 percent less pasta afterward-even though they were offered as much as they wanted. The secret, say researchers, is the sheer volume of a salad, which makes you feel too full to pig out. Health bonus: A study published in the Journal of the American Dietetic Association found that people who ate one salad a day with dressing had higher levels of vitamins C and E, folic acid, lycopene, and carotenoids-all disease fighters-than those who didn’t add salad to their daily menu.

4. Green tea. The slimming ingredient isn’t caffeine. Antioxidants called catechins are what help speed metabolism and fat burning. In a recent Japanese study, 35 men who drank a bottle of oolong tea mixed with green tea catechins lost weight, boosted their metabolism, and had a significant drop in their body mass index. Health bonus: The participants also lowered their (bad) LDL cholesterol.


5. Pears. They’re now recognized as having more fiber, thanks to a corrected calculation by the U.S. Food and Drug Administration. At six grams (formerly four grams) per medium-size pear, they’re great at filling you up. Apples come in second, with about three grams per medium-size fruit. Both contain pectin fiber, which decreases blood-sugar levels, helping you avoid between-meal snacking. This may explain why, in a Brazilian study that lasted 12 weeks, overweight women who ate three small pears or apples a day lost more weight than women on the same diet who ate three oat cookies daily instead of the fruit.

6. Soup. A cup of chicken soup is as appetite blunting as a piece of chicken: That was the finding of a Purdue University study with 18 women and 13 men. Why? Researchers speculate that even the simplest soup satisfies hunger because your brain perceives it as filling.

7. Lean beef. It’s what’s for dinner-or should be, if you’re trying to shed pounds. The amino acid leucine, which is abundant in proteins like meat and fish as well as in dairy products, can help you pare down while maintaining calorie-burning muscle. That’s what it did for 24 overweight middle-aged women in a study at the University of Illinois at Urbana-Champaign. Eating anywhere from nine to 10 ounces of beef a day on a roughly 1,700-calorie diet helped the women lose more weight, more fat, and less muscle mass than a control group consuming the same number of calories, but less protein. The beef eaters also had fewer hunger pangs.

8. Olive oil. Fight off middle-age pounds with extra virgin olive oil. A monounsaturated fat, it’ll help you burn calories. In an Australian study, 12 postmenopausal women (ages 57 to 73) were given a breakfast cereal dressed either with a mixture of cream and skim milk or half an ounce of olive oil and skim milk. The women who ate the oil-laced muesli boosted their metabolism. Don’t want to add olive oil to your oatmeal? That’s OK-it works just as well in salad dressings, as a bread dip, or for sautéing.


9. Grapefruit. It’s back! A 2006 study of 91 obese people conducted at the Nutrition and Metabolic Research Center at Scripps Clinic found that eating half a grapefruit before each meal or drinking a serving of the juice three times a day helped people drop more than three pounds over 12 weeks. The fruit’s phytochemicals reduce insulin levels, a process that may force your body to convert calories into energy rather than flab.

10. Cinnamon. Sprinkle it on microwave oatmeal or whole-grain toast to help cure those mid-afternoon sugar slumps. Research from the U.S.
Department of Agriculture found that a little cinnamon can help control post-meal insulin spikes, which make you feel hungry. Health bonus: One USDA study showed that just a quarter teaspoon of cinnamon a day lowered the blood sugar, cholesterol, and triglyceride levels in people with type 2 diabetes.

11. Vinegar. It’s a great filler-upper. In a Swedish study, researchers found that people who ate bread dipped in vinegar felt fuller than those who had their slices plain. The probable reason: Acetic acid in the vinegar may slow the passage of food from the stomach into the small intestine, so your tummy stays full longer. Vinegar can also short-circuit the swift blood-sugar rise that occurs after you eat refined carbs such as white bread, cookies, and crackers.

12. Tofu. It seems too light to be filling, but a study at Louisiana State University showed that tofu does the job. Researchers tested it against chicken as a pre-meal appetizer for 42 overweight women-and the participants who had tofu ate less food during the meal. The secret: Tofu is an appetite-quashing protein.


13. Nuts. Yes, they are fattening: A handful of peanuts is about 165 calories. But research shows that people who snack on nuts tend to be slimmer than those who don’t. A study from Purdue University found that when a group of 15 normal-weight people added about 500 calories worth of peanuts to their regular diet, they consumed less at subsequent meals. The participants also revved up their resting metabolism by 11 percent, which means they burned more calories even when relaxing. Health bonus: Walnuts contain omega-3 fatty acids. And researchers at Loma Linda University recently found that eating 10 to 20 whole pecans daily can reduce heart disease risks.

14. High-fiber cereal. Studies show that you can curb your appetite by eating a bowl for breakfast. But how well does it really work? Researchers at the VA Medical Center and the University of Minnesota in Minneapolis tested the theory against the ultimate diet challenge: the buffet table. They gave 14 volunteers one of five cereals before sending them out to the smorgasbord. Those who’d had the highest-fiber cereal ate less than those who didn’t have as much fiber in the morning. Try General Mills Fiber One (14 grams per serving) or Kellogg’s All Bran With Extra Fiber (13 grams per serving).

15. Hot red pepper. Eating a bowl of spicy chili regularly can help you lose weight. In a Japanese study, 13 women who ate breakfast foods with red pepper (think southwestern omelet) ate less than they normally did at lunch. The magic ingredient may be capsaicin, which helps suppress appetite.

GoogleNews.com, WSJ.com, July 24, 2009, by Abraham Verghese MD  —  At a moment when everyone’s joining the debate over health-care reform, who speaks for medicine?

By ‘medicine’ I mean that ancient art and science with origins before Hippocrates, that discipline that has the patient at its center; I’m talking about the ‘medicine’ that deans across the country will invoke in a few weeks as they exhort first-year medical students to embrace the ideals and values of the noble profession.


Abraham Verghese, M.D.

Our esteemed medical societies and academies aren’t speaking for medicine; they are lobbyists, defending their financial self-interests, lining up for or against the latest bill being proposed. Our great academic institutions and our esteemed medical schools have historically spoken for the cause of medicine, but these days many medical schools are more like big companies with complex financial interests in large hospitals and clinical practices. What about the large foundations dedicated to health care, such as the Robert Wood Johnson Foundation or the Kaiser Family Foundation? I think their voices have become more potent as they seem largely free of the kinds of conflicts of interest that bind many of us, but they are not quite the voice of medicine.

Before we are irretrievably sucked into Washington’s political maneuvering, we desperately need doctors and nurses to speak for the art of medicine. As William Osler, the father and spokesperson of modern medicine said a century ago:

You are in this profession as a calling, not as a business; as a calling which exacts from you at every turn self-sacrifice, devotion, love and tenderness to your fellow-men. Once you get down to a purely business level, your influence is gone and the true light of your life is dimmed. You must work in the missionary sprit with a breadth of charity that raises you far above the petty jealousies of life.

For some physicians, that quote is risible. But for many others, particularly for our medical students, those words resonate with the passion that brought them to medicine.

The rhetoric I’ve heard from President Obama comes closer to Osler’s vision than anything uttered lately from high-profile doctors. That must change: Our leaders in Washington — Democrats and Republicans — need true physicians by their side, not just lobbyists, as they negotiate these next few weeks and months.

I know of primary-care doctors who give their weekends to clinics for the homeless; I know of specialists who volunteer their services to community nonprofits. At a time when many practitioners turn down Medicare and Medicaid patients because government reimbursements don’t even pay for overhead costs, others continue to treat them. Long before concierge medicine made house calls fashionable and lucrative, practitioners I know in Laredo and El Paso made home visits to the housebound, poor and elderly. And then of course there is our new Surgeon General-a dedicated primary care physician, a strong signal from the President about the kind of doctors the nation needs.

Physicians like those should speak up for medicine, and argue in favor of paying doctors to spend time with their patients. They should fight against a payment system that has created perverse incentives that encourage unnecessary treatments. Let’s make it as lucrative to talk to the patient as it is to do to the patient.

A physician who gets to know the patient can discuss difficult subjects such as end-of-life care while the patient is still relatively healthy — often sparing them the pain and huge expense of spending their last days of life in an intensive care unit. Physicians with good relationships with their patients can guide them away from futile therapies whose only proven efficacy is making money for drug companies, hospitals and doctors. How wonderful if all our lobbying societies would agree that our goal should be to fulfill Dr. Peabody’s old maxim, and not to simply restate it generation after generation: “The secret of the care of the patient is in caring for the patient.”

Abraham Verghese is a practicing internist and a professor of medicine at Stanford. His most recent book is Cutting for Stone.


Wellness is one piece left out of the health care reform debate.

NYTimes, 07/24/09  —  In the United States, health care would be better termed “disease care.” That’s because insurance companies tend to reward doctors and hospitals for diagnosing and treating illnesses, but there’s little financial incentive to spend time with patients and develop strategies for preventing illness. The bottom line: there’s not a lot of money in staying well.

Getting Good Value in Health Care

The New York Times, July 24, 2009, by Pauline W. Chen MD  —  Like most doctors I know, every time I see a patient in clinic, questions scroll down my mind’s eye like credits at the end of a movie. Over the years, I have whittled down the number of questions, from the exhausting repertoire I memorized as a medical student to the streamlined clinical checklist I use today.

Some of the questions I ask are generic: What brings you here today? What medications are you taking? Some are specialized: Was your liver transplant done “piggy back”? Have you had any episodes of rejection? But a few of the questions have nothing to do with the work I do or the care I am trained to offer. Rather, they are questions about being well and preventing disease: Are you exercising? Do you smoke? Have you had a mammogram?

For years I believed that this last group of questions was a clinician’s equivalent of performing a good deed. After all, discussing such topics could help a patient avoid the kind of potentially preventable diseases I had seen other patients suffer from. And since I knew that countless health care resources had been depleted while caring for those patients, I also couldn’t help but feel as if bringing up these questions with patients, however briefly, was like contributing to some greater public good. Any kind of preventive care that I could offer as a doctor, I believed, had to save money.

But it turns out that at least one of my assumptions – that I could help to save money – was erroneous. Sort of.

In the enormous pie that makes up health care expenditures, only 1 to 3 percent can be attributed to preventive interventions. The miniscule size of this share is due in part to the fact that very few clinical preventive services actually result in savings. In fact, the data for savings is so lackluster that some economists have argued that it is less cost-effective to prevent illness than it is to simply let people get sick. Other economists have taken that argument even further, contending that preventive care adds to societal costs by extending lives and thus the time we must care for people (though one would hope that costly treatments might result in the same “problem”).

But according to Dr. Steven H. Woolf, a professor of family medicine at the Virginia Commonwealth University in Richmond and a leading expert on preventive care, all of these assertions are premised on the wrong question. In a commentary published earlier this year in The Journal of the American Medical Association, Dr. Woolf maintains that the economic argument for disease prevention rests not on how much people save but on how much value they gain for each dollar spent.

“Health is a good, like food or gas,” Dr. Woolf said. “When you go to a grocery store or gas up a car, you don’t ask whether it will produce a net savings. You don’t expect the cashier to give you money back. The more appropriate question is whether we are getting good value for the money we’re spending.”

To help determine value, Dr. Woolf utilizes a unit of measurement – the Quality Adjusted Life Year, or QALY. QALY has been used historically in studies to assess the relative value of different interventions, with each intervention carrying a “price tag” or a rough estimate of the cost to save a comparable year of life.

Viewed in terms of QALY value then, there are indeed some clinical preventive services that confer few health benefits for the amount of money spent. But several preventive interventions turn out to be downright bargains. Childhood immunizations and smoking cessation cost so little per QALY (less than $5,000 per QALY gained) that they may actually end up yielding net savings. Other preventive services, like taking aspirin daily if you are at high risk for cardiovascular disease, cost roughly a third to a fifth of more expensive disease interventions that are now routinely paid for, like angioplasty, the procedure that widens or “roto-rooters” narrowed heart vessels.

There is also value added beyond these cost efficiency calculations. Last fall, the National Commission on Prevention Priorities found that by increasing just five preventive services, clinicians could save more than 100,000 lives per year. These services include breast cancer screening in women 40 and older, flu immunizations in adults 50 and over, colorectal cancer screening in adults 50 and over, smoking cessation counseling, and a daily aspirin in high risk cardiovascular patients.

Much of the responsibility of these preventive services currently rests on clinicians’ shoulders. This focus has contributed in part to the poor data regarding preventive medicine‘s results, since relying on clinical settings alone is a relatively inefficient way of changing health behaviors and preventing illness. “Putting it all on doctors and the clinical setting is not a powerful formula,” Dr. Woolf noted. “What is unique about prevention is that so much is happening outside of the clinical setting. Good preventive care requires breaking down the boundaries and getting beyond the constraints of a doctor’s appointment. It requires thinking more broadly in terms of a community-based approach.”

It is in this way that preventive medicine offers an additional public good: the potential to strengthen and broaden how we define the patient-doctor relationship.

To that end, Dr. Woolf and his colleagues recently spearheaded a program using electronic medical records to link nine physician practices to several community services that offered telephone and group counseling services. “If their patients who smoked were interested,” Dr. Woolf said, “doctors could click a button and auto-enroll the patient with the state’s quit smoking line. Two days later, those patients would receive a call to enroll.” Dr. Woolf’s group created similar electronic links to Weight Watchers and to Alcoholics Anonymous.

These quick and reliable connections between physicians and community-based programs resulted in significant improvements for patients and a higher rate of referrals from doctors. “It’s not feasible for doctors to offer intensive smoking cessation counseling in 15 minutes and to be there through the whole process,” Dr. Woolf said. “The barriers to change are at home, work, school, the store. That’s where people need help with behavior change. The last physician or emergency room visit only goes so far.” Such connections are even more critical for patients with chronic diseases, since these individuals often have complicated care plans and can benefit tremendously from increased coordination with preventive and caregiving resources in the community.

All of these links, however, require additional outside support, at least initially. “What is needed is a third party,” Dr. Woolf said, “individuals apart from the busy physicians or busy community organizations who can work out the logistical details. Once you have done that, it takes literally seconds to connect the dots for patients.”

But as long as the focus is on savings and not on value, such support is not likely to be forthcoming, and preventive care stands to remain a nearly negligible part of our health care expenditures.

“Community health and wellness have been pushed aside in the health care reform debate partly because we have been focused on net savings, not value,” Dr. Woolf observed. “That analysis has not been favorable with preventive medicine, so people continue to get highly expensive studies and procedures that are ineffective, even though we have cost-effective public health interventions at our fingertips.”

“It’s as if our house is going up in flames,” Dr. Woolf continued. “There is one room, filled with explosives, that hasn’t yet caught on fire. But people are hesitating to put out the fire because they believe they don’t have the data.”


Vaccine testing — set to begin next week — could lessen impact
CDC.gov, GoogleNews.com, July 24, 2009, by Steven Reinberg — The H1N1 swine flu could end up affecting as many as 40 percent of Americans, if one includes workers who stay home to care for people who contract the illness, U.S. health officials said Friday.

The projection from the U.S. Centers for Disease Control and Prevention is based on the influenza pandemic in 1957, when almost 70,000 people in the United States died from the flu.

“Our planning assumptions for a severe pandemic were that up to 40 percent of the workforce might be affected and not able to work, either because they were ill or because they needed to stay home to care for an ill family member,” Dr. Anne Schuchat, director of CDC’s National Center for Immunization and Respiratory Diseases, said Friday in a press conference.

But even if the new H1N1 virus never reaches that proportion, it is expected to gain strength come fall.

“We had a 6 to 8 percent attack rate just during the spring months,” Schuchat said. “We think that in a longer winter season, attack rates would be two to three times as high as that,” she said.

A public health campaign and a vaccination program, which will probably begin in October, could reduce the impact of the H1N1 swine flu, she said.

“We think we can limit, somewhat, the illness and severe complications of that kind of virus circulation with updated guidance and, of course, with the efforts we are making towards the development of a vaccine,” Schuchat said.

Vaccine trials, already underway in Australia, are expected to begin in the United States next week, Schuchat said.

U.S. officials hope to have 160 million doses of injectable swine flu vaccine on hand by October, with more doses coming in the form of a nasal spray — if trials of experimental vaccines are successful.

To determine who should receive the vaccine first, the CDC’s Advisory Committee on Immunization Practices will meet Wednesday.

In the Southern Hemisphere, where it is winter now, seasonal flu and the new H1N1 swine flu continue to spread, Schuchat said.

The good news is that “specimens we have collected have not changed. They are still the same strain we are seeing here, meaning that the vaccine we are working on is directed against the strain that is still active both here in the U.S. and in Southern Hemisphere countries,” she said.

Also, the CDC, in this week’s Morbidity and Mortality Weekly Report, cited four children in Texas who developed neurological complications from encephalitis, associated with the H1N1 flu. Two of them also had seizures, but all recovered and had no lasting neurological effects after leaving the hospital.

“This is a reminder that seizure, encephalitis and other neurologic complications can occur in the setting of influenza,” she said.

Although less severe in summer, the H1N1 swine flu continues to spread, especially in summer camps and schools, Schuchat said.

Reacting to reports that some camps are giving children the antiviral drug Tamiflu in hopes of preventing the virus, Schuchat advised against this. Camps should follow the CDC’s guidelines on protecting campers from the flu, she said.

Giving antiviral medications in hopes of providing a general immunity can increase the odds that the virus will become resistant to the drugs, Schuchat said. To date, five cases of the H1N1 flu have proved resistant to Tamiflu, she noted. So far, this resistant strain has not been passed on to anyone else, she said.

The CDC also reported Friday that there have been 43,771 confirmed cases of H1N1 infection and 302 deaths in the United States, although officials believe more than 1 million Americans have been stricken with swine flu. The reason for the disparity: The virus continues to produce mild symptoms and patients typically recover quickly. This was the final CDC report of case numbers, Schuchat said, noting in the future it will document swine flu trends.

By Erik Vance

Researchers demonstrate a role for the brain’s connective tissue in learning a new task

[Published 21st July 2009 04:12 PM GMT]



The brain’s white matter – generally thought to play second fiddle to the neurons that make up the grey matter – expands along with nearby grey matter when a person learns a new task, scientists at Oxford University report.


MRI of a head
Image: Wikipedia Commons

Just as new neurons may be formed during learning, corresponding new cells in the white matter may be generated as well, said Jan Scholz, a student in the lab of Heidi Johansen-Berg at Oxford University, at a San Francisco meeting of the Organization for Human Brain Mapping last month.

“It’s the first time that experience-related white matter changes have been seen,” Scholz told The Scientist.

White matter is often called the wiring of the brain because it connects individual neuron and groups of neurons together. Whether or not it plays a role in learning or cognition, though, is something of a mystery. The Oxford work built on a 2004 Nature paper that showed that cortical grey matter, which consists largely of neuronal cell bodies, expanded in people learning to juggle. In the present study, the Oxford team examined the effects of the same task on the brain’s white matter, which comprises connective tissue such as myelin and axons.

Scholz and Johansen-Berg, from Oxford’s Centre for Functional Magnetic Imaging of the Brain (FMRIB), taught 24 healthy, right-handed volunteers to juggle. They scanned subjects’ brains using diffusion MRI before the six weeks of training, directly after, and then again after four weeks of abstinence from juggling. Diffusion MRI measures how water diffuses within a brain structure, for instance showing how thick myelin in white matter might be.

The researchers observed grey matter “changes in structure” in a part of the parietal lobe associated with spatial coordination — a change which Scholz told The Scientist probably reflects neurogenesis. Myelin in that region also appeared thicker, which he similarly attributed to myelinogenesis. Those gains then eroded after four weeks of no juggling. This temporal and spatial correlation shows that the two tissue types are working in concert.

“People have long thought of grey matter and white matter as independent structures, but they are clearly actually quite interdependent,” said Adeline Vanderver, a neurologist and white matter expert at the National Children’s Medical Center in Washington, DC, of the results. “What I think is really interesting is that clearly the cells are working together.”

She added, though, that whether or not neurogenesis and myelogenesis were at play was difficult to determine. “You can’t say based on the functional imaging and fractional anisotropy what is going on at a cellular level.”

Silvia Bunge, a neuroscientist at University of California Berkeley, said that the demonstration of a link between white matter and grey matter is “hugely important” for the study of learning in humans, especially children. Indeed, her PhD student Kirstie Whitaker is looking at similar white matter development in school children.

“White matter is important — that has been shown over the last 5-10 years. But it is definitely a new area of investigation.” Whitaker said. “It’s exciting to see a training study where over the course of six weeks they can see changes [in white matter] and reverse those changes.”

Pinning down the role of white matter may help scientists understand brain networks. Elucidating the mechanism by which the tissue expands may also provide clues to treatments for diseases such as multiple sclerosis, which results from withering of myelin in the central nervous system.

“It’s one of these thing that now that you look back on it you say, ‘Oh, that must be happening,’ but no one had ever thought of it quite that way,” said Vanderver of combined white/grey matter growth. “A better understanding of this interdependency will help us help people’s brains.”

The New York Times, July 24, 2009, by Tara Parker-Pope  —  How old do you feel? And how old will you be when you reach old age?

The public’s views on age and aging are explored in a new national survey on aging from the Pew Research Center, explained in a story (below)  by my colleague Sarah Arnquist.

Most adults over age 50 feel at least 10 years younger than their actual age, the survey found. One-third of those between 65 and 74 said they felt 10 to 19 years younger, and one-sixth of people 75 and older said they felt 20 years younger.

And at what age does old age begin? Most people in the survey said old age starts at age 68. Are they kidding? That seems way too young to me. Not surprisingly, most people over 65 have a different idea about old age. Among those getting the senior citizen discount, most say old age begins at 75.

Now consider the answer given by people under 30. Most of them think you’re old by the time you hit 60.

The New York Times, July 24, 2009, by Sarah Arnquist  —  The older people become, the younger they feel and the more likely they are to see “old age” as a time occurring later in life, according to a national survey on aging released in late June 2009. 

“There’s a saying that you’re never too old to feel young, and boy, have older Americans today taken that one to heart,” said Paul Taylor, executive vice president with the Pew Research Center and the survey’s principal author. He said this is the broadest survey the nonpartisan research center has ever done to gauge Americans’ views on aging.

Currently, about 40 million Americans, or one in eight, are 65 and older. By 2050, one in five American will be in that age group. The center surveyed about 3,000 adults 18 and older via land and cellular telephone lines in February and March of this year.

The survey found not just a gap between actual age and the age people say they feel, but also that the gap between reality and perception increases with age.

Most adults over age 50 feel at least 10 years younger than their actual age, the survey found. One-third of those between 65 and 74 said they felt 10 to 19 years younger, and one-sixth of people 75 and older said they felt 20 years younger.

On average, survey respondents said old age begins at 68. But few people over 65 agreed; they said old age begins at 75.

Respondents under 30 said 60 marks the beginning of old age.

“Old age is always a bit older than you are,” said Jeffrey Love, research director at AARP.

The researchers also asked young adults what they expect aging to be like and older Americans how it actually is. Younger people tend to think growing old will be worse than the elderly report, the survey team found.

Older adults said they had experienced the negative aspects of aging – including illness, loneliness and financial difficulty – far less often than younger people anticipated. But older participants also said they found less time for family and leisure activities than younger adults expected they would when they reach old age.

“Human beings have trouble coming to terms with the unknown,” Mr. Taylor said. “Growing old is a great unknown in the lives of everyone who is not yet old.”


The New York Times, July 24, 2009, by Roni Caryn Rabin  —  Many studies have suggested that a diet rich in fish is good for the heart. Now there is new evidence that such a diet may ward off dementia as well. One of the largest efforts to document a connection – and the first such study undertaken in the developing world – has found that older adults in Asia and Latin America were less likely to develop dementia if they regularly consumed fish.

And the more fish they ate, the lower their risk, the report found. The findings appeared in the August issue of The American Journal of Clinical Nutrition.

The study, which included 15,000 people ages 65 and older in China, India, Cuba, Venezuela, Mexico, Peru and the Dominican Republic, found that those who ate fish nearly every day were almost 20 percent less likely to develop dementia than those who ate fish just a few days a week. Adults who ate fish a few days a week were almost 20 percent less likely to develop dementia than those who ate no fish at all.

“There is a gradient effect, so the more fish you eat, the less likely you are to get dementia,” said Dr. Emiliano Albanese, a clinical epidemiologist at King’s College London and the senior author of the study. “Exactly the opposite is true for meat,” he added. “The more meat you eat, the more likely you are to have dementia.” Other studies have shown that red meat in particular may be bad for the brain.

Fish, especially oily fish, may be protective against dementia because it is rich in omega-3 long-chain polyunsaturated fatty acids, which studies suggest may have numerous health benefits, among them anti-inflammatory properties. Omega-3 fatty acids have been shown in animal studies to reduce the build-up of atherosclerotic plaques and may also prevent the accumulation of amyloid plaques in the brain characteristic of Alzheimer’s disease, Dr. Albanese said.

But though numerous observational studies in the West also have indicated fish may reduce dementia risk, there is little evidence as yet from randomized controlled clinical trials, which provide the best scientific evidence but are expensive and difficult to carry out.

Although the new study was an observational study, Dr. Albanese suggested that since the findings are consistent both in the West and in developing countries, where the environment and lifestyle are so different, the new data lend support to the hypothesis that fish is protective against dementia.

Most of the elderly surveyed in the study lived with extended families, and those seniors who had electricity and indoor plumbing, or several assets like a car, a phone, a TV or a refrigerator were considered relatively well off.

Researchers assessed the dietary habits of 14,960 study participants by going door-to-door to do face-to-face interviews, and they diagnosed dementia by using culturally validated criteria. The data were adjusted to account for differences in such variables as sex, age, education, income, smoking and physical health.


← Previous PageNext Page →