Obesity Gene Identified by British Scientist

A gene that contributes to obesity has been identified for the first time, promising to explain why some people easily put on weight while others with similar lifestyles stay slim.

People who inherit one version of the gene rather than another are 70 percent more likely to be obese, British scientists have discovered. One in six people has the most vulnerable genetic make-up and weighs an average 3 kilograms more than those with the lowest risk. They also have 15 percent more body fat.

The findings provide the first robust link between a common gene and obesity, and could eventually lead to new ways of tackling one of the most significant causes of ill health in the developed world. One in four British adults is classified as obese, and half of men and a third of women are overweight.

Obesity is a main cause of heart disease, cancer and type 2 diabetes. An adviser to the Government’s health spending watchdog said recently that the condition was a bigger national danger than smoking, alcohol or poverty.

If the biological function of the gene, known as FTO, can now be understood, it could become possible to design drugs that manipulate it to help people to control their weight.

“Even though we have yet to fully understand the role played by the FTO gene in obesity, our findings are a source of great excitement,” Mark McCarthy, of the University of Oxford, who led the research, said.

Genome of Rhesus Monkey Mapped by Scientists

Scientists have unraveled the DNA of another of our primate relatives, this time a monkey named the rhesus macaque — and the work has far more immediate impact than just to study evolution.

These fuzzy animals are key to testing the safety of many medicines, and understanding such diseases as AIDS, and the new research will help scientists finally be sure when they're a good stand-in for humans.

"The thing we're all fascinated with is what makes us different from these animals who are so close to us," said Dr. Richard Gibbs of the Baylor College of Medicine, who led a team of more than 170 scientists that collaborated on the project.

In Friday's edition of the journal Science, the researchers report deciphering the macaque's DNA and comparing it to the genetic blueprints of humans and chimpanzees, our closest living relatives.

Among the most intriguing discoveries so far: a list of diseases where the same genetic mutation that makes people ill seems normal for the macaques.

"That is really quite a stunner," said Dr. Francis Collins, genetics chief at the National Institutes of Health, which funded the research. "It gives you a glimmer of how subtle changes in DNA cause big trouble."

The mapping of the human genome in 2001 sparked an explosion of work to similarly decipher the DNA of other animals, so scientists could compare species in the effort to understand the functions of various genes.

The rhesus macaque is the third primate genome to be completed, work that promises to greatly enhance understanding of primate evolution, perhaps even to help explain what makes us human.

Not surprisingly, the DNA of humans, chimps and macaques are highly similar. Humans and chimps have evolved separately since splitting from a common ancestor about 6 million years ago, but still have almost 99 percent of their gene sequences in common.

Macaques branched off from the ape family tree far earlier, about 25 million years ago — yet still share about 93 percent of their DNA with humans, the new work shows.

Here's the key: Six million years isn't long in evolutionary history. So if a particular gene is different in the human and the chimp, it's impossible to know which version came first.

Add these more ancient Old World monkeys into the mix, however, and it may be possible to tease out genetic changes that were important for key traits of modern humans, such as higher brain power and walking upright.

"That does point us, in a much more powerful way, to answering the question, 'What does humanness mean?' at the DNA level," said Collins, director of NIH's National Human Genome Research Institute.

But right away, the work raises some important biomedical questions, because rhesus macaques are ubiquitous in medical research.

Most vaccines and many drugs are tested in the monkeys before ever reaching people. And they're used as models of many human diseases, most notably the AIDS virus.

"As models, we expect them to behave like us," noted Baylor's Gibbs.

Yet consider some of the differences found so far:

— About one in 14,000 babies is born with PKU, or phenylketonuria, meaning their bodies can't process a protein found in most foods called phenylalanine. Without treatment, PKU causes mental retardation. But in macaques, the gene defect that causes PKU seems to cause no harm, suggesting they may somehow compensate in a way people can't.

The researchers found a list of such mutations, from ones linked with cystic fibrosis to blood diseases, that are bad news for people but seem normal in the monkeys. Most involved metabolic disorders that in turn can harm the brain, a link Gibbs found particularly compelling.

— The monkeys had triple the number of genes as people to do run one arm of the immune system. That raises immediate questions about how they react in vaccine or AIDS research.

"It would make sense that a comprehensive knowledge of their immune machinery should be a part of those studies," Gibbs said.

— On the other hand, macaques had far fewer of a family of cancer-related genes than either humans or chimps.

Gibbs said the work has importance for the animals, too — because knowing their genetic makeup should cut the number of monkeys needed in many biomedical experiments.

"It's really about experimenting less and being able to learn more," he said.

Stay tuned: More primate gene maps are on the way, including blueprints for orangutans, gorillas and gibbons.

Vegetarian Form of DHA Omega-3 Lowers Diastolic Blood Pressure

Made from microalgae under tightly controlled manufacturing conditions, life'sDHA is free of oceanic contaminants that may be present in certain fish or fish oils.


Martek's life's DHA from microalgae successfully reduces diastolic blood pressure in middle-aged subjects, according to an independent study published in the April issue of the Journal of Nutrition. The study, conducted at King's College, London, reported a significant reduction in diastolic blood pressure. The investigators noted that this reduction is likely to be of clinical significance with regard to risk of future vascular events. This is the first study to assess the effects on blood pressure of intakes of DHA alone at less than 1.0 g per day. The study was neither funded nor sponsored by Martek Biosciences, but used Martek's life'sDHA as its algal DHA source.

The study involved 38 middle-aged subjects with an average age of 49 and an average blood pressure of 122/79 mmHg. Subjects randomly received either a 0.7 g per day of DHA or placebo for three months. Diastolic blood pressure decreased by an average of 3.3 mmHg. No significant changes occurred in systolic blood pressure. The daily DHA supplement increased DHA levels in red blood cells (erythrocytes) by 58 percent.

"This research is further evidence supporting the cardiovascular health benefits of Martek's life'sDHA," said Steve Dubin, CEO of Martek Biosciences.

Martek's life'sDHA is a vegetarian form of DHA omega-3, a long chain omega-3 fatty acid that serves as a primary building block for the brain and the eye and supports brain, eye and cardiovascular health throughout life. There is a large and growing body of scientific evidence demonstrating that people of all ages, from infants to aging adults, benefit from an adequate supply of DHA omega-3 in the diet. Scientific reviews have noted the importance of DHA omega-3 in proper brain and eye development and function, and there are clinical studies underway to evaluate its role in decreasing the prevalence of certain neurological disorders. Yet despite its importance, Americans have among the lowest dietary intakes of DHA omega-3 in the world.

Martek's life'sDHA is unique in the market because it is derived from a sustainable and vegetarian source. Made from microalgae under tightly controlled manufacturing conditions, life'sDHA is free of oceanic contaminants that may be present in certain fish or fish oils. Microalgae are the only vegetarian source of DHA omega-3, the key omega-3 for brain and eye development and function.

Doctors in Bosnia go on strike

Doctors and other medical workers in the Muslim-Croat half of Bosnia went on strike Monday, demanding better salaries and regulations in the health sector, their union said.


Doctors in Bosnia go on strike

Some 22,000 doctors, nurses and others said they will treat only urgent cases until there is a new plan that will equalize salaries, pensions and other benefits in the entire federation is adopted.

"Health workers asked citizens for understanding and solidarity, so that we can, with joint efforts, force the federation government to finally take seriously the problems in the health sector and create a new action plan to solve them in the entire federation," the union statement said.

Medical workers in Bosnia have an average salary of EUR400 (US$540) and the salaries in each of the federation's 10 cantons differ.

"The difficult financial situation of some of the doctors in the federation has put doctors on the edge of pure existence," the union said.

Federation officials declined to comment on the strike, which will continue until an action plan is created, according to the union.

The peace agreement that ended the 1992-95 war left the country divided into a Muslim-Croat federation and a Bosnian Serb mini-state. Each have their own government, ministries and police and are linked only by joint state institutions, like the country's three-member presidency.

Long-Term Therapy Effective in Bipolar Depression

Psychotherapy for as long as nine months is significantly more effective than short-term treatment for alleviating depression associated with bipolar disease, new research suggests.

The drugs used to treat depression are of limited use in treating the repeating depressive episodes of bipolar illness, according to background information in the article, published last week in The Archives of General Psychiatry.

The researchers studied 293 patients with bipolar disease at 15 medical centers nationwide. They randomly assigned one group of 163 people to one of three kinds of psychotherapy (cognitive behavioral therapy, interpersonal and social rhythm therapy, or family therapy) consisting of up to 30 50-minute sessions over nine months.

A second group of 130 patients was assigned to “collaborative care,” three sessions over six weeks designed to offer a brief version of the most common psychological and behavioral strategies shown to be beneficial in bipolar illness. The participants, whose average age was 40, were followed for one year, and all were also being treated with mood-stabilizing medicines.

Cognitive behavioral therapy focuses on challenging and controlling negative thoughts. In interpersonal and social rhythm therapy, patients concentrate on stabilizing daily routines and resolving interpersonal problems. Family therapy engages family members to help solve problems related to the illness, like failing to take medication properly, and to reduce the number of negative family interactions.

Therapists at each of the 15 medical centers received brief training in the therapies they administered.

“The study included real-world patients experiencing the early phases of a depressive episode,” said David J. Miklowitz, the study’s lead author and a professor of psychology and psychiatry at the University of Colorado. “And the therapists who delivered the treatment were trained by experts in the field with low-intensity training, which is typical of what’s available in real-life practice.”

Recovery rates after one year were a combined average of 64 percent for the intensive therapy groups, but only 52 percent for those who had brief therapy. In any given month, the researchers calculated, a patient undergoing longer-term therapy was more than one and a half times as likely to be well as one who had short-term treatment. Family therapy was slightly more effective than interpersonal or cognitive behavioral therapy, but the differences among the types of intensive treatment were not statistically significant.

“This is a monumental study,” said Myrna M. Weissman, a professor of psychiatry at Columbia who was not involved in the work. “There are no pharmaceutical companies willing to pay for research in psychotherapy, so we don’t have many clinical trials.” But, she added: “Psychosocial treatment for bipolar illness is not an alternative to medication. It’s a supplement.”

The authors, one of whom has received grant support and consulting fees from several pharmaceutical companies, found that the median time to recovery for the patients in long-term therapy was 169 days, compared with 279 days for those who received the brief treatment.

The cost of long-term therapy is high, and insurance companies are reluctant to cover it. But according to Dr. Weissman, the cost of not covering it could be higher. “It isn’t just the cost of the therapy. It’s the long-term cost. Bipolar illness has devastating effects on families as well as on the patients themselves.”

Polyphenols Protect Against Numerous Diseases

Polyphenols help control free radical formation in humans and slow cell ageing. First and foremost, they are found in fruit and vegetables, but also in processed goods such as chocolate, tea or wine.


27/03/07 These molecules with antioxidant properties are found in the most common consumer products. They protect against numerous diseases. Polyphenols help control free radical formation in humans and slow cell ageing. First and foremost, they are found in fruit and vegetables, but also in processed goods such as chocolate, tea or wine. Humans consume around a gramme of polyphenols a day, which is more than ten times the figure for vitamin C.

Strawberries, lychees and grapes are the fruits with the highest polyphenol content, but vegetables are not far behind, particularly artichokes, parsley and brussels sprouts. Moreover, total consumption also plays a role. As Pierre Brat points out: "If we look at total polyphenol content in apples, they rank fifth compared to other fruits, but the extent of their consumption places them first!". Likewise, in terms of vegetables, potatoes rank just 19th, but their massive consumption means that they account for almost 60% of the polyphenols obtained from vegetables.

This prompted CIRAD and its partners to create a database, to set product composition against consumption. In all, the total polyphenol content of 162 vegetable and 71 fruit samples, along with 85 tea samples, was analysed. The results were used to compile a composition and consumption table, with values for 28 fruits and 24 vegetables.

Study Suggests New Avenue on Diabetes

Thirteen young diabetics in Brazil have been able to stop receiving insulin after being treated with stem cells taken from their own blood, researchers are reporting.

The experimental procedure has enabled the young people, who have Type 1 diabetes, to live free of insulin shots for as long as three years so far, according to the study, being published Wednesday in The Journal of the American Medical Association.

Larger, more rigorous studies are needed to determine if stem cell transplants could become standard treatment for people with the disease, once called juvenile diabetes, which is much less common than Type 2, associated with obesity. While promising for future research, the study did not involve a comparison group with which to make sure the treatment was indeed better than standard diabetes care.

The research was done in Brazil because doctors in the United States were not interested in the approach, said one of the authors, Dr. Richard K Burt of Northwestern University’s medical school.

The patients ranged in age from 14 to 31 and were newly found to have Type 1 diabetes, an autoimmune disease in which the body attacks insulin-producing cells in the pancreas. Insulin is needed to regulate blood sugar levels, which when too high can lead to heart disease, blindness, nerve problems and kidney damage.

The purpose of the stem cell transplant was to stop the body’s attack on the pancreas. A study published last year described a different kind of experimental transplant, using pancreas cells from donated cadavers, that enabled a few diabetics to give up insulin shots. But that requires lifelong use of anti-rejection medicine, which the patients in Brazil do not need since the stem cells were their own.

In the newly reported study, 15 diabetics were treated at a bone marrow center at the University of São Paulo. In each case, the disease was diagnosed before the patients’ insulin-producing cells had been destroyed. That timing is crucial, Dr. Burt said. “If you wait too long,” he said, “you’ve exceeded the body’s ability to repair itself.”

Indeed, part of the procedure entails several days of high-dose chemotherapy, which virtually shuts down the immune system and so stops destruction of the few insulin-producing cells that the body has not already destroyed. The harvested stem cells, when injected back into the body, then build a new, healthier immune system that does not attack such cells.

Patients were hospitalized for about three weeks. Many had side effects including nausea, vomiting and hair loss. One developed pneumonia, the only severe complication.

Doctors changed the drug regimen after the treatment failed in the first patient, who ended up needing more insulin than before the study. Another patient also relapsed.

The remaining 13 “live a normal life without taking insulin,” said another author, Dr. Julio C. Voltarelli of the University of São Paulo. “They all went back to their lives.”

The patients enrolled in the study at different times, and so the length of time that they have been free of the need to take insulin also differs.

Agency Urges Change in Antibiotics for Gonorrhea

The rates of drug-resistant gonorrhea in the United States have increased so greatly in the last five years that doctors should now treat the infection with a different class of antibiotics, the last line of defense for the sexually transmitted disease, officials said yesterday.

The percentage of drug-resistant gonorrhea cases among heterosexual men jumped, to 6.7 percent in 2006 compared with 0.6 percent in 2001, officials from the Centers for Disease Control and Prevention said.

Standard monitoring of gonorrhea cases is conducted among men who go to S.T.D. clinics. New data from such sites in 26 cities show that rates of drug-resistant gonorrhea among heterosexual men at the clinics last year reached 26 percent in Philadelphia and more than 20 percent in Honolulu and four areas in California, Long Beach, Orange County, San Diego and San Francisco.

Among gay men at the clinics, the rates of the bacterial infection jumped, to 38 percent in the first half of 2006 from 1.6 percent in 2001.

For 14 years, most cases of gonorrhea have been treated with a class of antibiotics known as fluoroquinolones. Now, officials at the center are urging doctors to prescribe drugs in the cephalosporin class.

No new antibiotics for gonorrhea are in the pipeline, officials of the centers told reporters by telephone.

“Now we are down to one class of drugs,” said Dr. Gail Bolan, an expert in sexually transmitted diseases at the California Department of Health Services. “That’s a very perilous situation to be in.”

Dr. Bolan is a spokeswoman for the Infectious Diseases Society of America, a professional organization.

Health officials are also concerned about extremely drug-resistant tuberculosis and a number of other microbes like Pseudomonas aeruginosa, Klebsiella penumoniae and Acinetobacter species that are resistant to most antibiotics.

The United States has an estimated 700,000 new cases of gonorrhea a year, occurring among sexually active people of both genders at all ages. It is the second most commonly reported infectious disease, behind chlamydia, another sexually transmitted disease.

After a substantial decline from 1975 to 1997, the gonorrhea rates had leveled off in recent years.

Action was taken yesterday because the level of resistance has exceeded the standard of 5 percent set by the centers and the World Health Organization. Although the centers’ recommendations are not binding, physicians generally follow them.

“We are running out of options,” said Dr. John M. Douglas Jr., who directs the division of sexually transmitted diseases prevention at the centers. Cephalosporins, like their cousin penicillin, thwart bacteria by damaging a microbe’s cell wall, not by attacking DNA as the fluoroquinolones do, Dr. Douglas said.

Gonorrhea has not shown resistance to the cephalosporins, which were first marketed in the United States in the 1980s, Dr. Douglas said. Now “increased vigilance is essential,” he said, because resistance could still develop at any time, particularly with increased usage.

The disease centers say doctors should now prescribe ceftriaxone, sold as Rocephin, which is injected once into a muscle. The centers also recommend the one-time use of cefixime, or Suprax, but tablets of cefixime are not available in the recommended 400-milligram dose.

These drugs are meant to substitute for the three currently recommended fluoroquinolones, ciprofloxacin, or Cipro; ofloxacin, or Floxin; and levofloxacin, or Levaquin.

For patients allergic to cephalosphins, the centers recommend one injection of spectinomycin, a drug not available in the United States.

Over the years, gonorrhea has become resistant to a number of antibiotic classes starting with sulfa, then penicillin and the tetracyclines before fluoroquinolones.

The disease centers have gradually cautioned against using fluoroquinolones because of the emergence of resistance in different regions.

In 2000, the centers recommended against fluoroquinolones for any patient who acquired gonorrhea in Hawaii, other Pacific Islands and Asia. The agency extended the recommendation to California in 2002. In 2004, the centers recommended that fluoroquinolones not be used among gay men with gonorrhea.

In 2005, Britain recommended against using fluoroquinolones for gonorrhea because of a resistance problem there.

The centers do not plan a letter to doctors on the recommendations. They are relying on news reports and state and local health departments to spread the information.

Adding Folic Acid to Flour Helps Prevent Neural Tube Defects

Folic acid in bread at the 50micro-gram and 100micro-gram levels consumed twice with a 4-hour interval in between slices was fully metabolised each time.

Public consumption of folic acid from fortified flour at current mandated US levels (100micro-gram/day) and at double this amount is probably safe, at average intakes, according to an article published in the open access journal BMC Public Health. The research has implications for the UK and Republic of Ireland, which plan to follow the US by adding folic acid to flour to help prevent neural tube defects in the near future.

Dr. Mary Rose Sweeney and her colleagues from Trinity College Dublin commissioned a local bakery to bake three batches of bread, with different levels of folic acid. Single slices from the three batches contained 50micro-grams, 100micro-grams and 200micro-grams folic acid. The authors pre-saturated subjects first with daily 400micro-grams folic acid supplement, and subsequently tested them with a regime of two slices per day of the specially-prepared breads. Hourly blood tests determined whether folic acid was fully metabolised, and how long it remained in the blood.

Folic acid in bread at the 50micro-gram and 100micro-gram levels consumed twice with a 4-hour interval in between slices was fully metabolised each time. However a 400micro-gram supplement or 200micro-gram consumed once in a single slice of bread lead to metabolised folic acid in test subjects blood Long-term surveillance of the population is required to see whether folic acid accumulates, and to assess and potential safety implications.

Professor John Scott said: "this is good news in that it is possible to have optimum protection from a neural tube defect affected birth without having exposure to un-metabolised folic acid".

In fact the levels consumed currently in the US are thought to be in the range of 215-240micro-grams due to overage (the practice of adding a little extra to meet the mandate). Consumers may also get folic acid from other dietary sources, such as fortified cereals. The recommended dose for women of childbearing age in the UK is 400micro-grams per day.

Neural tube defects include spina bifida and anencephaly, which is fatal. Sufficient folic acid before and during pregnancy averts most neural tube defects. The neural tube develops in the first four weeks of pregnancy, often before many women know they are pregnant.

Few Breast Surgeons Steer Patients to Reconstruction

A large proportion of breast surgeons never refer their patients to a plastic surgeon for reconstruction, a new study reports.

Researchers surveyed 365 surgeons with 1,844 patients in Detroit and Los Angeles in 2002. Only 24 percent of surgeons referred more than three-quarters of their patients for plastic surgery, and 44 percent referred fewer than one-quarter.

Over all, fewer than 20 percent of breast cancer patients undergo breast reconstruction, according to background information in the article, which appeared online March 26 in the journal Cancer.

Surgeons who had a large volume of cases and those who worked in specialized cancer centers were more likely than others to refer patients for plastic surgery. And, while 62 percent of women referred more than three-quarters of their patients, only 28 percent of men did.

When the surgeons were asked why they did not refer women for breast reconstruction, 64 percent said their patients were not interested, 39 percent believed that their patients thought it would take too long, and almost half said the women were concerned about the cost, even though federal law mandates insurance coverage for breast reconstruction.

“Women should know that breast reconstruction is an option, and not just for wealthy women,” said Dr. Amy K. Alderman, an author of the study and an assistant professor at the University of Michigan. “Women should be able to talk to their health care provider about what those options are for them. And if their health care provider doesn’t bring it up, then women should do so themselves.”

A Lively Libido? For What Group

Here’s a new word for you: obsolagnium. You may not find it in an ordinary dictionary. But if you are over 50, you may well be familiar with the concept, because it means “waning sexual desire resulting from age.”

In fact, it is rarely age per se that accounts for declines in libido among those in the second half-century of life. Rather, it can be any of a dozen or more factors more common in older people that account for the changes. Many of these factors are subject to modification that can restore, if not the sexual energy of youth, at least the desire to seek and the ability to enjoy sex.

Nor is it just hormones. Addressing only the distaff half of the population, the Boston Women’s Health Book Collective, in its newest work, “Our Bodies, Ourselves: Menopause,” points out: “Our sexual desire and satisfaction may be influenced by our life circumstances, including the quality of our sexual relationships, our emotional and physical health, and our values and thoughts about sexuality, as well as by the aging process and the shifting hormone levels that occur during the menopause transition.”

The same, of course, is true of men. Difficult life circumstances can do much to dampen anyone’s libido. Stress at work or home, looming bankruptcy, impending divorce, serious illness, depression, a history of sexual abuse and a host of medications are among the many things that can put a big crimp in your desire for sex at any age.

Feel Attractive, Be Attractive

As people age, both physical and emotional changes occur that can influence libido. Wrinkles, hair loss, declining muscle mass and accumulation of body fat, among other age-related changes, can make men and women feel less attractive. And if you don’t see yourself as attractive, your brain may respond by dampening any impulse you might have to be intimate with someone.

I have no studies to corroborate this idea, but I strongly suspect that older people who stay in shape physically, keep their brains stimulated and remain interested in a variety of activities are likely to feel more attractive and be more attractive — and thus more libidinous — than those who let themselves go to pot, as it were. I’m not suggesting that people in their 60s and 70s start dressing and acting like 20-somethings, but there are any number of age-appropriate actions that can help people see themselves — and help others see them — as sexually desirable beings.

Of course, illness, both mental and physical, can seriously disrupt a healthy libido at any age. Diseases of the adrenal, pituitary or thyroid glands can diminish sexual desire, as can depression and anxiety. Likewise, several common cancers — especially cancers of the breast, testes or prostate or the drugs used to treat them — may suppress the desire for sex.

Many commonly administered medications can interfere with sexual desire, performance or both. Among the most frequent offenders are antidepressants and antianxiety drugs, blood pressure medications and opioid pain relievers. High doses of alcohol likewise blunt desire as well as performance. Even drugs taken to curb heartburn can curb the desire for sex. In some instances, changing the dose, switching to a different drug or taking a brief drug holiday (say, for the weekend) can boost libido.

A Change of Scene

While a drug like Viagra may help a man temporarily overcome disease- or medication-induced erectile dysfunction, it does nothing to increase desire, which is essential for these potency-enhancing drugs to work.

Knowing how to please each other sustains sexual interest for many long-established couples. But for others, familiarity can breed boredom; they lose interest in doing the same old thing the same old way time after time.

Novelty is a well-established sexual stimulant. An unattached man or woman in midlife or beyond who had all but forgotten about sex meets someone new and attractive, and suddenly the flames of sex are reignited. This can happen, too, to very old people. Stories abound in assisted living and nursing home facilities of elderly widows and widowers whose long-dormant sexuality is reawakened by attraction to a new, albeit equally old, partner.

Of course, changing partners is not a realistic option for those in a long-standing monogamous relationship in which sexual intimacy is just a fond memory.

But there are ways for such couples to introduce novelty — ranging from a change of venue or techniques to an exchange of fantasies or even the introduction of sex toys — that may rekindle sexual feelings.

Even young couples can find their interest in sex diminished by a fear of interruption or being overheard by children or an elderly parent. It can take some effort — and perhaps a lock on the bedroom door and background music — to reduce the risk of distractions that blunt the flame of desire.

Women may think that the decline in estrogen at menopause is responsible for their loss of interest in sex. But estrogen loss is only an indirect factor; it can result in vaginal tightness and dryness that renders intercourse painful rather than pleasurable. The use of lubricants and a dildo or more frequent sex can often counteract these effects. But for some women, the use of a vaginal estrogen cream or suppository is necessary to make sex comfortable and more desirable.

The Testosterone Factor

But the real libido hormone, for both men and women, is testosterone, which women produce in their ovaries and adrenal glands. As other ovarian hormone levels drop after menopause or surgical removal of the ovaries, so does the amount of desire-boosting testosterone. This has prompted some women to use testosterone replacement therapy to get their sex lives back on track. One drug commonly prescribed off-label is Estratest, a combination of small doses of estrogen and testosterone. Some doctors tailor-make low-dose testosterone preparations for women. A testosterone patch for women has not been approved by the Food and Drug Administration because of insufficient safety data.

Women taking testosterone should be carefully monitored, because safe levels of the hormone for women have not been determined. Common side effects include unwanted hair growth and a deepening of the voice. Women who have had breast or uterine cancer or diseases of the liver or heart should avoid testosterone replacement.

Sexual desire among men, too, can be squelched by low levels of testosterone. While there is no official recognition of male menopause, men experience declining levels of hormones as they age — what some experts called andropause — that can affect sexual desire and performance. Other symptoms of this deficiency may include enlarged breasts, loss of body or facial hair, and osteoporosis before age 65.

Testosterone replacement is helpful in restoring the sex drive only of men who have low levels of the hormone. A test of testosterone levels should be done and other causes (besides age) should be ruled out before the hormone is prescribed. Risks include prostate enlargement and prostate cancer.

Circumcision! A step to prevent AIDS

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W.H.O. Urges Circumcision to Reduce Spread of AIDS (March 29, 2007)

How do you persuade a grown man to get circumcised?

Answer: it’s not easy, even in America, where most men are circumcised at birth.

Now that three clinical trials in Africa have shown that circumcision helps protect men against AIDS and the World Health Organization has endorsed it, public health doctors elsewhere — including in New York City — are contemplating whether to recommend it. Then comes the difficult part — how to sell the idea.

Unfortunately, the data from Africa does not translate well. Those trials were of heterosexual men in countries where the virus is everywhere, education about safe sex is practically nonexistent, and condoms get in the way of the need to father children.

In the United States, the AIDS epidemic is very different. The highest risk groups are men having sex with men (whether openly or covertly or even forcibly — in prison rapes, for example), people who share needles and women who, often unknowingly, have sex with high-risk men. Although it has been killing people here for 25 years, AIDS has not turned into a generalized epidemic like it has in Africa. Sex education, condoms, abstinence, antiretroviral drugs and the fear of death have concentrated it mostly in small pockets of the population.

And for most of those people, circumcision probably won’t do much good. It might help protect gay men who are exclusively “tops” — that is, they have only penetrative anal sex, never receptive. It presumably would protect men having sex with infected women. It might protect women who choose circumcised men — but even that wasn’t proved in the African studies, which had to be stopped early because the benefit for men was so glaring.

Because of these unknowables, no domestic medical authority, from the New York City Health Department to the American Urological Association, has a policy on adult circumcision yet.

And, besides, there hasn’t been a groundswell of demand.

“We haven’t gotten a lot of calls,” said Noel Alicea, a spokesman for Gay Men’s Health Crisis, which runs a hotline.

“Not a one,” said Tokes Osubu, executive director of Gay Men of African Descent.

“A few,” said Mark McLaurin, executive director of the New York State Black Gay Network. “The first ones wanted to make sure that it wasn’t going to be mandatory. And then there were others who said ‘Tell me more — how much does this reduce my risk?’ ”

Mr. McLaurin said he would advise most gay men to “hold off until we have more data.”

But, he added, “for someone who was predominantly or exclusively a top, and said he was really having a hard time reducing his risk by practicing safe sex — I’d have a hard time recommending against it.”

But, he quickly added, he was certain that few men in his network would want it.

“We’ve had a hard time recruiting black and Latino men even for vaccine trials,” he said.

“Because of everything from Tuskegee on up,” he explained — referring to the notorious medical experiment in which black men with syphilis were left untreated for decades — many black Americans mistrust the medical establishment.

In Africa, it is relatively easy to talk men into getting circumcised, said Daniel Halperin, an AIDS researcher at the Harvard School of Public Health who has interviewed hundreds of African men about sex, AIDS and local customs.

Some tribes circumcise teenagers to welcome them to full manhood. Many men who can’t get enough water to bathe regularly think foreskins are unhygenic. And some, he said, “say circumcised men get all the women” because of a widespread belief that, with slightly lessened sensation, they can make love longer.

(Circumcision’s effect on sex is a white-hot issue in the United States for the small but vocal anticircumcision lobby. The lobby’s main focus is on advice to parents of baby boys, but it has offshoot groups, like the “uncuts” who insist that sex with uncircumcised men is superior, and the “foreskin restoration movement” which utilizes tape, small weights and parental resentment.)

For adult men, circumcision takes about 30 minutes, said Dr. Craig Niederberger, chief of male reproductive surgery at the University of Illinois at Chicago. It is an outpatient procedure and, like dental work, can be done with local injections of Novocain.

“But with many men,” he added, “if you use the words ‘scalpel’ and ‘penis’ in the same sentence, they say ‘put me to sleep!’ So then we do it under general anesthesia.”

There is no official national estimate of how many adults have the operation each year.

Most of his patients have phimosis or balanitis — a painfully tight foreskin or swollen glans, which can become a crisis if urination is blocked.

But, because he practices in a black Chicago neighborhood, some of his young, healthy patients are volunteers — perhaps the only demographic group of African-American men currently lining up for the operation.

They are converts to Islam, which requires circumcision.

“They come in very committed,” he said. “It’s a personal choice that’s very strong.”

A spokeswoman for the Nation of Islam, the Black Muslim group also based in south Chicago, said she presumed most adherents were circumcised at birth, “but I’m the wrong person to ask,” she added. A male official she suggested for comment did not return a phone call.

In any case, that appears to be the answer: Until more trials are done, it’s going to take a medical emergency. Or divine intervention.

Hip replacement

Hip replacement, an operation that about 300,000 Americans undergo each year, is one of the great success stories of modern medicine.

This is the first in a series of articles that will address pocketbook and other consumer considerations involved in choosing and using health care.

But woe to those who outlive their artificial hips, which typically cannot be counted on to last more than 20 years or so.

Because it is difficult to extract and replace a worn-out or defective artificial hip, doctors routinely advise patients to put off hip replacement as long as possible. For middle-aged or younger people whose hips have been damaged by disease or injury, that typically means a punishing waiting game.

Now, though, an alternative to total hip replacement can offer an interim solution to many younger patients.

The alternative, called hip resurfacing, usually yields at least as many short-term benefits as a total replacement. It costs about the same and is typically covered by insurance.

And though many patients can expect to outlive the treatment’s effectiveness, hip resurfacing has the advantage of preserving enough healthy bone to allow for a future total hip implant.

“It’s nice to know that down the road, if necessary, it will be an original total hip — not a revision,” said Keith McDonald, a 54-year-old air traffic controller from Melville, N.Y., whose right hip was resurfaced late last month. This past Tuesday, just 15 days after the operation — and at least a week earlier than doctors would recommend — Mr. McDonald drove his car. “Every day I do more,” he said.

Tens of thousands of patients around the world have had hips resurfaced in the past decade. That includes some Americans who went overseas before the Food and Drug Administration started allowing it to be done in this country last May.

“The demand from patients and surgeons is tremendous,” said Brian Austin, of Smith & Nephew, the British maker of the F.D.A.-approved resurfacing system.

More than 400 surgeons in the United States have now been trained to use Smith & Nephew’s product, which is known as the Birmingham Hip System. Competing devices already sold overseas are expected to begin arriving in this country later this year.

For all its potential advantages, hip resurfacing surgery is actually no easier for the patient or doctor than hip replacement. And the recuperation may not be any quicker. While many activities can be resumed within weeks, complete healing can take six months or longer.

And a number of medical and health conditions, like kidney disease and obesity, may make even young patients poor candidates for resurfacing.

There are enough potential drawbacks, in fact, that doctors offering hip resurfacing say — as they do with standard hip replacements — that the procedure should be deferred as long as possible. That typically means waiting as long as the patient can tolerate the pain from the arthritis, bone damage or other conditions afflicting the hip.


“You should have pain every day before you even think about it,” said Dr. William B. Macaulay Jr., a Manhattan surgeon who is one of this country’s leading practitioners of hip resurfacing. “If you are doing it in people with moderate pain who just want to improve their tennis game, that’s crazy.”

Experts say that 10 percent to 15 percent of hip-replacement candidates may find hip resurfacing a viable alternative. But unless they are Web-savvy like Mr. McDonald, who learned about it only through his own Internet research, they may not have heard about the procedure.

Patient-support Web sites like Surfacehippy often post complaints from patients saying that surgeons not trained in resurfacing tend not to tell their patients about it.

“I’ve been a volunteer paramedic with the Melville Fire Department since 1971, so I’m interested in medicine and not reluctant to do research on the Web,” said Mr. McDonald, recalling how he had discovered resurfacing and found Dr. Macaulay, the surgeon who operated on him.

Vincent Torretta, a second patient who underwent hip resurfacing with Dr. Macaulay the same day as Mr. McDonald, also discovered the procedure through his own Web research. Mr. Torretta, 60, a loan data analyst with Bank of New York, lives halfway up a mountainside near the Pennsylvania border in Glen Spey, N.Y. He sought relief when chronic pain in his left hip and knee left him unable to pursue outdoor activities.

He found that Dr. Macaulay, the director of the Center for Hip and Knee Replacement at NewYork-Presbyterian/Columbia hospital, was the nearest expert in resurfacing.

“It sounded like it would allow me to lead a more active life,” Mr. Torretta said.

He said his insurer, United Healthcare, initially denied coverage because he wanted to go out of the approved doctors’ network and that several of the United representatives whom he spoke with on the phone were confused because they had never heard of the procedure. United eventually provided oral approval. Mr. Torretta still did not have that in writing by the time he underwent the operation.

Publicity about the procedure may soon pick up. Stryker, a big American maker of artificial joints, is expected to begin marketing a similar British-designed device by early fall. Another device maker, Wright Medical, is close on its heels.

Other big orthopedics companies like Zimmer Holdings, Biomet and the DePuy Orthopaedics division of Johnson & Johnson that are selling resurfacing systems overseas are further from getting approval in this country.

The true facts on strangulation.

What is strangulation, how is it done and what happens in the body of someone who is strangled. Here are some interesting facts on the topic:

* When someone is strangled, his windpipe is blocked by pressure around the neck. Pressure on the larynx or the trachea causes asphyxia. The air flow is interrupted, as is the flow of oxygen to the brain. This could lead to unconsciousness and death.

* There are three types of strangulation: manual, ligature and choke hold. In the first instance hands and fingers are used, in the second a rope or some sort of fabric is used, and in the last either a noose or a specially designed device.

* Strangulation stops oxygenated blood from getting to the brain. In severe cases this could lead to brain damage and death. Pressure on the larynx or the trachea causes asphyxia.

* It can take as little as 7 -14 seconds for someone to die if a chokehold is applied effectively. But few people last more than a minute or two, unless they somehow manage to loosen the stranglehold.

* Physical strength is needed to strangle someone manually. It is not a method of murder that is favoured by people who lack physical strength, as they will be unable to overpower their victim.

* When a person is hanged, they are asphyxiated by their own body weight pulling on the noose. With manual or ligature strangulation this is not the case.

* Forensic signs of manual strangulation include small round bruises, scratch marks (as the victim tried to loosen the stranglehold), blueness of the tongue, bleeding under the skin and damage to the larynx.

* Ligature marks can leave a wide bruise while wires or cords can cut into the neck or leave a sharp line.

* Hanging is a favoured method of suicide, but it impossible for anyone to strangle themselves in any other way, as with loss of consciousness breathing resumes.

* Contrary to popular opinion death by strangulation is mostly not caused by the restriction of air flow to the lungs, but by a lack of oxygen flow to the brain.

Presence of guns in homes is strongly Associated with higher suicide rates

The presence of guns in homes is strongly associated with higher suicide rates, a new US study found.

Harvard School of Public Health researchers analysed US data and found that states with higher rates of households with guns had significantly higher rates of suicide by men, women and children. In the 15 states with the highest rates of household gun ownership, twice as many people committed suicide than in the six states with the lowest levels of household gun ownership. All the states had similar populations.

Although guns are involved in only five percent of all fatal and non-fatal suicide attempts, more than 90 percent of all suicidal attempts using guns are fatal, the study said. By comparison, drugs are used in 75 percent of all suicide attempts but are fatal only three percent of the time.

Suicide is one of the 15 leading causes of death in the United States. Among people younger than 45, suicide is one of the top three causes of death. In 2004, guns were used by more than half of the 32 439 Americans who committed suicide.

The study authors said that gun owners need to take steps to make their homes safer. The findings are published in the April issue of the Journal of Trauma.
Remove all firearms
"Removing all firearms from one's home is one of the most effective and straightforward steps that household decision-makers can take to reduce the risk of suicide," study lead author Matthew Miller, assistant professor of health policy and management, said in a prepared statement.

"Removing firearms may be especially effective in reducing the risk of suicide among adolescents and other potentially impulsive members of their home. Short of removing all firearms, the next best thing is to make sure that all guns in homes are very securely locked up and stored separately from secured ammunition. In a nation where more than half of all suicides are gun suicides and where more than one in three homes have firearms, one cannot talk about suicide without talking about guns," Miller said.

Sexual desire

Sexual desire. The phrase alone holds such loaded, voluptuous power that the mere expression of it sounds like a come-on — a little pungent, a little smutty, a little comical and possibly indictable.

Everybody with a pair of currently or formerly active gonads knows about sexual desire. It is a near-universal experience, the invisible clause on one’s birth certificate stipulating that one will, upon reaching maturity, feel the urge to engage in activities often associated with the issuance of more birth certificates.

Yet universal does not mean uniform, and the definitions of sexual desire can be as quirky and personalized as the very chromosomal combinations that sexual reproduction will yield. Ask an assortment of men and women, “What is sexual desire, and how do you know you’re feeling it?” and after some initial embarrassed mutterings and demands for anonymity, they answer as follows:

“There’s a little bit of adrenaline, a puffing of the chest, a bit of anticipatory tongue motion,” said a divorced lawyer in his late 40s.

“I feel relaxed, warm and comfortable,” said a designer in her 30s.

“A yearning to kiss or grab someone who might respond,” said a male filmmaker, 50. “Or if I’m alone, to call up exes.”

“Listening to Noam Chomsky,” said a psychologist in her 50s, “always turns me on.”

For researchers in the field of human sexuality, the wide variance in how people characterize sexual desire and describe its most salient features is a source of challenge and opportunity, pleasure and pain. “We throw around the term ‘sexual desire’ as though we’re all sure we’re talking about the same thing,” said Lisa M. Diamond, an associate professor of psychology at the University of Utah. “But it’s clear from the research that people have very different operational definitions about what desire is.”

At the same time, the researchers said, it is precisely the complexity of sexual desire, the depth, richness and tangled spangle of its weave, that call out to be understood.

An understanding could hardly come too soon. In an era when the rates of sexually transmitted diseases continue to climb; when schools and parent groups spar bitterly over curriculums for sex education classes; when the Food and Drug Administration angers both religious conservatives and women’s groups by approving the sale of the morning-after pill over the counter but then limiting those sales to women 18 years or older; and when deviations from the putative norm of monogamous heterosexuality are presented as threats to the social fabric — at such a time, scientists argue that the clear-eyed study of sexual desire and its consequences is vital to public health, public sanity, public comity.

“Sexual desire may be complicated, but that doesn’t mean it’s chaotic,” said Julia R. Heiman, director of the Kinsey Institute for Research in Sex, Gender and Reproduction in Bloomington, Ind. “We can make an honest attempt to understand what sexual desire is and what it is not, and that it is important to do so.”

Meredith L. Chivers, a researcher at the Center for Addiction and Mental Health in Toronto, concurs. “Sexuality is such a huge part of who we are. How could we not want to understand it?”

Unabashed about acting on their academic appetites, sexologists have gained a wealth of new and often surprising insights into the nature and architecture of sexual desire. They are tracing how men and women diverge in their experience, and where they converge. They are learning how and why people pursue the erotic partners they do, and the circumstances under which those tastes are either fixed or fluid.

Some researchers are delving into the neural, anatomical and emotional mechanisms that modulate and micromanage sexual desire and sexual arousal; others are exploring the role that culture plays in plucking or muffling the strings of desire. The pragmatists in sexology’s ranks are seeking better bedside medicines — new ways to help people who feel they suffer from an excess or deficit of sexual desire.

One recent standout discovery upends the canonical model of how the typical sex act unfolds, particularly for women but very likely for men as well.

According to the sequence put forward in the mid-20th century by the pioneering sex researchers William H. Masters, Virginia E. Johnson and Helen Singer Kaplan, a sexual encounter begins with desire, a craving for sex that arises of its own accord and prods a person to seek a partner. That encounter then leads to sexual arousal, followed by sexual excitement, a desperate fumbling with buttons and related clothing fasteners, a lot of funny noises, climax and resolution (I will never drink Southern Comfort at the company barbecue again).

A plethora of new findings, however, suggest that the experience of desire may be less a forerunner to sex than an afterthought, the cognitive overlay that the brain gives to the sensation of already having been aroused by some sort of physical or subliminal stimulus — a brush on the back of the neck, say, or the sight of a ripe apple, or wearing a hard hat on a construction site and being surrounded by other men in similar haberdashery.

In a series of studies at the University of Amsterdam, Ellen Laan, Stephanie Both and Mark Spiering demonstrated that the body’s entire motor system is activated almost instantly by exposure to sexual images, and that the more intensely sexual the visuals, the stronger the electric signals emitted by the participants’ so-called spinal tendious reflexes. By the looks of it, Dr. Laan said, the body is primed for sex before the mind has had a moment to leer.

“We think that sexual desire emerges from sexual stimulation, the activation of one’s sexual system,” she said in a telephone interview.

GM mozzies battle malaria

US researchers have created genetically-modified mosquitoes resistant to a malaria parasite, raising the possibility of one day stopping the spread of the disease, a new study says.

The genetically-engineered mosquitoes outbred natural mosquitoes when fed malaria-infected blood from mice, according to the study published Monday in the Proceedings of the National Academy of Sciences.
The research offers the possibility of controlling malaria by introducing the genetically altered insects into the wild and having them take over from their natural cousins.

The scientists at Johns Hopkins University in Baltimore, Maryland combined equal numbers of genetically engineered and natural mosquitoes in the laboratory and let them feed on malaria-infected mice.

GM mozzies wins evolution race
The genetically-altered insects survived in greater numbers and laid more eggs. After nine generations, 70 percent of the mosquitoes were genetically-modified compared to 50 percent at the outset of the experiment, Marcelo Jacobs-Lorena and his colleagues wrote.

The study suggested that when feeding on malaria-infected blood, "transgenic malaria-resistant mosquitoes have a selective advantage over non-transgenic mosquitoes," the authors wrote.

The lab-altered mosquitoes competed equally well with natural insects when fed non-infected blood but did not outbreed their natural counterparts in that case, according to the study.

For the strategy against malaria to be effective, transgenic mosquitoes would have to outbreed the natural insects when feeding off untainted blood.

Not ready for prime time
Further research was still needed before the altered insects could be released into the wild, as only a small percentage of mosquitoes in nature are exposed to malaria, the authors wrote.

Still, the research carried "important implications for implementation of malaria control by means of genetic modification of mosquitoes," the authors wrote.

The experiment used the malaria parasite P. berghei, and not the more dangerous parasite - Plasmodium falciparum - responsible for the most serious malaria affecting humans.

Each year 350 to 500 million people are infected with malaria and 700 000 to 2.7 million die from the disease, including more than a million children in Africa, according to the World Health Organization.

Flu Vaccine from Eggs

he latest buzz in flu vaccine development could be the use of an insect-cell-based vaccine, rather than egg-based immunisations, to speed up production and maintain effectiveness, particularly in the case of a pandemic flu outbreak.

An experimental vaccine was tested in about 300 people and produced an immune response strong enough to fight off the flu, while only causing minimal side effects, such as pain at the site of the injection, researchers reported in the April 11 issue of the Journal of the American Medical Association.

"All currently licensed influenza vaccines in the United States are produced in embryonic hen's eggs," wrote the study authors, from Cincinnati Children's Hospital Medical Centre, the University of Rochester and the University of Virginia. The authors also pointed out that "eggs require specialized manufacturing facilities and could be difficult to scale up rapidly in response to an emerging need such as a pandemic."

The influenza vaccine is the only known way to try to prevent the flu.
Eggs can be tricky
But, as the authors pointed out, developing a vaccine from eggs can be difficult. Millions and millions of eggs have to be kept at the right temperature, and flu viruses don't always grow well in eggs. Also, people who are allergic to eggs can't use egg-based vaccines.

But, one of the biggest difficulties stemming from the use of egg-based vaccines is the time it takes to manufacture these immunisations.

"It takes about six to nine months to make a batch, so you have to anticipate what will be the emerging flu strains almost a year ahead of time," explained Dr Marc Siegel, an internist at New York University Medical Centre and author of Bird Flu: Everything You Need to Know About the Next Pandemic.

"One advantage of this new vaccine technology - assuming that it's clinically useful - is that it would allow you to choose what the emerging strain is much closer to when it is actually emerging," he said.

The new vaccine, currently called FluB1OK, is produced by Protein Sciences Corp. of Meriden, Connecticut. A virus that normally infects insects called baculovirus and cells from caterpillars are used to manufacture the vaccine.
How the study was conducted
For this study, which was funded by Protein Sciences Corp., the researchers compared a placebo to two different versions of the new vaccine. One contained 75 micrograms of the vaccine, the other 135 micrograms. The actual vaccines were designed to protect against three strains of flu that were expected to be most active during the 2004-05 flu season, when the study was conducted.

One hundred and fifty-four people received a placebo injection, while 153 received the smaller dose of vaccine, and another 153 received the largest dose.

The vaccine was well-tolerated. Pain around the injection site was the most commonly reported "adverse event."
Vaccine found to protect
More important, no one who received the largest vaccine dose contracted the flu, compared to almost 5 percent of those who received a placebo and slightly more than 1 percent of those on the smaller dose of vaccine.

"In this study, (the new vaccine) was safe and immunogenic in a healthy adult population," wrote the study authors.

"This is a very promising, but early, finding," said Siegel, who added that "we need more studies that look at non egg-based technologies." – (HealthDayNews)

Stem cells, diabetes success

A pilot study of people newly diagnosed with type 1 diabetes found that stem cell therapy eliminated the need for insulin therapy for varying periods of time.

This is the first trial to look at stem cell therapy in humans with this form of the disease. But experts stressed that the research is preliminary and urged caution when interpreting the results, which are published in the April 11 issue of the Journal of the American Medical Association.

"This may be the first step in something that could be promising, but I need to see a control group and longer follow-up before I'd go out on a limb," said Dr Jay S. Skyler, author of an accompanying editorial in the journal and associate director of the Diabetes Research Institute at the University of Miami Miller School of Medicine. "But this is worthy of further experimentation."

Type 1 diabetes develops when the body's immune system attacks the pancreatic beta cells, which produce insulin - the hormone that transports sugar from the blood to cells for energy.
Restoring the balance
"In type 1 diabetes, the immune system is out of balance," Skyler explained. "Ordinarily, all of us have some cells with the potential to destroy the pancreas, but the regulatory immune system prevents those cells from becoming sufficiently active. In type 1 (diabetes), there's a greater proportion of activity of the destroying cells and lesser activity of the regulatory cells. The goal is to try to bring that back into balance."

By the time a person is diagnosed with the disease, some 60 percent to 80 percent of the beta cells have already been destroyed. And people who have more functioning beta cells tend to have fewer complications down the line, research has shown.

Immunosuppression therapy, designed to dampen the immune system, can help, but these patients still need to take insulin to regulate their blood sugar. Meanwhile, stem cell therapy has had some success with other autoimmune diseases, such as lupus, but not with type 1 diabetes.

"There has been use of this specific procedure in other autoimmune disease in human beings with some suggestion of promise of effect, and it's been advocated for a number of years that this kind of approach might be useful in type 1 diabetes," Skyler said.
How the study was conducted
The new study, conducted by scientists in Sao Paolo, Brazil, and in Chicago, involved 15 patients newly diagnosed with type 1 diabetes. All participants underwent high-dose immunosuppression therapy followed by a procedure called autologous nonmyeloablative haematopoietic stem cell transplantation (AHST) to preserve beta-cell function.

AHST involves removing a patient's own blood stem cells, treating them, and then returning them to the patient.

"Using bone marrow precursor cells, which are precursors of immune T-cells, is designed to reset the immune system," Skyler said. "The reason for choosing a point early in time is that you want to have enough beta cells that are still left."
Some insulin independence achieved
During follow-up that lasted up to 36 months, 93 percent of the patients achieved some length of insulin independence. Fourteen patients became insulin free - one for 35 months, four for at least 21 months, seven for at least six months. Two more participants who had late responses to the stem cell therapy became insulin free for one and five months, respectively.

One person developed pneumonia, and two others developed problems with their endocrine system, which governs hormones in the body.

It's unclear exactly how the stem cell transplants worked their magic. And there are still numerous questions.

"The obvious question is how long does it work and what is the risk of treatment," said Dr Larry Deeb, president of medicine and science at the American Diabetes Association. "But the excitement is where we are in diabetes research and treatment, and the excitement some of these questions generate for people who have diabetes and for the diabetes community and for the profound argument that this is not a time to be proposing less money for research in diabetes."

Smoking to stop Parkinson’s?

Could smoking cigarettes and drinking coffee protect you from Parkinson's disease?

That's the startling suggestion of a new US study of families that also found NSAID use has no impact on the disease risk.

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Previous studies have reported that consuming caffeine, smoking and taking nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen and naproxen may help prevent Parkinson's disease, according to background information in the study. But there's been little family-based research done to examine these links.

The new study, led by researcher Dana B. Hancock of Duke University Medical Centre in Durham, North Carolina, included 356 Parkinson's patients (averaging about 66 years of age) and 317 of their family members (averaging almost 64 years of age).
Smoking seems to protect
The people with Parkinson's disease were 44 percent less likely to report ever smoking and 70 percent less likely to report current smoking compared with unaffected relatives, the study authors found.

"Increasing intensity of coffee drinking was inversely associated with Parkinson's disease," they added. "Increasing dosage and intensity of total caffeine consumption were also inversely associated, with high dosage presenting a significant inverse association with Parkinson's disease."

The study found no link between NSAID use and Parkinson's disease.

The findings are published in the April issue of the journal Archives of Neurology.
Mechanism still a mystery
It's not known how smoking or caffeine consumption may help reduce the risk of developing Parkinson's disease.

"Given the complexity of Parkinson's disease, these environmental factors likely do not exert their effects in isolation, thus highlighting the importance of gene-environment interactions in determining Parkinson's disease susceptibility," the study authors wrote. "Smoking and caffeine possibly modify genetic effects in families with Parkinson's disease and should be considered as effect modifiers in candidate gene studies for Parkinson's disease."

Diabetes may spur dementia

Adults with diabetes may be at higher risk for developing mild cognitive impairment, a condition that is often seen as a precursor to Alzheimer's disease, new research found.

"There is mounting evidence that diabetes is bad for cognition," said Dr Jose A. Luchsinger, the lead author of the study and an assistant professor of medicine at Columbia University. "The mechanisms need to be elucidated. Type 2, or adult-onset diabetes, which the study refers to, is increasing in the US and in the world. The consequences of the potential cognitive complications of diabetes could be devastating from a public health standpoint."
More questions than answers
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Still, there are perhaps more questions than answers in the new study, which was published Monday in the April issue of Archives of Neurology.

"What is the real message for diabetes control?" asked Dr Larry Deeb, president of medicine and science for the American Diabetes Association. "If the message is that you're at greater risk for MCI (mild cognitive impairment) no matter what, that's one thing. If taking good care of blood sugar makes a difference, as seems to be the case for most other complications of diabetes, that's another thing. One would hope this might be another argument for controlling diabetes."

Health experts already knew that type 2 diabetes can be a risk factor for Alzheimer's disease. The evidence has been less clear on whether diabetes is related to a higher risk of mild cognitive impairment, often considered a bridge state between normalcy and Alzheimer's.

"There are few studies looking at the outcome of mild cognitive impairment," Luchsinger said.
How the study was conducted
For this study, Luchsinger and his colleagues looked at 918 men and women older than 65 (average age 75.9) who did not have mild cognitive impairment or dementia at the start of the study. The participants, all from northern Manhattan in New York City, were assessed every 18 months with an in-person interview as well as physical and neurological examinations.

Almost one-quarter - 23.9 percent - of the participants had diabetes, 68.2 percent had high blood pressure, 33.9 percent had heart disease, and 15 percent had suffered a stroke.

During follow-up that averaged 6.1 years, 334 of the participants developed mild cognitive impairment. And people with diabetes had a higher risk of having mild cognitive impairment, especially amnestic MCI, which affects memory more than non-amnestic MCI.
Diabetes tied to impairment
Overall, 8.8% of cases of mild cognitive impairment among the study participants could be attributable to diabetes. And the rates were higher for black Americans (8.4 percent) and Hispanics (11 percent) than for non-Hispanic whites (4.6 percent). This makes sense, given that minority populations in the United States have a higher prevalence of diabetes.

What explains the possible link between diabetes and impairment?

Diabetes could contribute to plaque build-up in the brain, with such a build-up a hallmark of Alzheimer's, the study authors said.

But, they added, more research is needed.

"Studies are needed to see if preventing diabetes prevents cognitive impairment and how diabetes treatment affects cognition," Luchsinger said. "We also need to see how cognitive impairment in persons with diabetes affects their ability to follow their treatment, which is usually complex and involves several medications."

Other experts applauded even the tentative findings.

This type of research may help target populations who could one day benefit from drugs, said Maria Carrillo, director of medical and scientific relations at the Alzheimer's Association.
Risk factors are real
"This supports the idea that risk factors are real," Carrillo added. "The field has now matured to a point where we can start looking at earlier and earlier aspects of the disease. It makes sense to look even earlier than that and try to tease out what the risk factors look like in that population, in case we have a disease-modifying drug coming up in near future."

"This is documenting what we know a little bit better and emphasising that patients should control their blood sugar as well as they can early in the disease," added Dr Joel Zonszein, director of the Clinical Diabetes Centre at Montefiore Medical Centre in New York City. "This is another piece of information, more wood to the fire."

A Patient’s Demands Versus a Doctor’s Convictions

Doctors talk all the time about a patient’s right to refuse treatment. But what about the right to demand it?

Not long ago, a middle-age man was admitted to the hospital where I work with fever and shortness of breath. The man, Eric, was in his early 40s, thin but toned, with colorful tattoos and a pallid countenance.

A chest X-ray showed fluid in his lungs, but doctors did not know why. An echocardiogram, an ultrasound of the heart, provided the answer. On one heart valve was an infected mass of tissue, a vegetation, flapping around wildly like a flag in the breeze. It had severely damaged the valve, resulting in congestive heart failure.

Heart infections can usually be treated with intravenous antibiotics; surgery is reserved for the most complicated cases. In Eric’s case, a CT scan of the head showed several small bleeding sites, probably caused by parts of the vegetation breaking off and lodging in the brain. Doctors decided that the valve needed to be replaced to prevent further injury.

A consulting neurologist recommended an M.R.I. before surgery to make sure that this infection had not caused any brain aneurysms that could rupture and bleed in the operating room, causing a stroke.

When the scan showed no aneurysms, the neurologist asked for a cerebral angiogram to exclude even tiny aneurysms that the M.R.I. might have missed. Though fairly routine, angiograms in rare cases can cause strokes, because a catheter is threaded into the arteries that supply blood to the brain. Eric decided that although he wanted the surgery, he did not want this test.

“You know what I think?” he said to me. “I think they’re just throwing everything at this, and maybe they’ll find something, and then what? They got an M.R.I., and they’re still not satisfied!”

I explained that the doctors were being cautious.

“Hey, I’ll sit here with antibiotics going into me, no problem,” he replied. “But doing a procedure that could cause a stroke? That’s getting a little scary.”

I pulled out my stethoscope so I could listen to his lungs. What if he refused the angiogram, he asked, leaning forward. Couldn’t he have the operation anyway?

I replied that the surgeon would probably not operate without the angiogram, a hunch confirmed the next day.

“But what if I sign a paper accepting the risk?”

The vague outlines of a memory started to form in my mind. “I doubt that’s going to change anyone’s mind,” I said. I told him that if he felt strongly enough, I could arrange for him to be transferred to another hospital.

He did not want to do that. “Oh well, it is what it is,” he said, shrugging, looking resigned. “They’re going to get what they want. It’s a losing battle.”

Though I agreed that an angiogram was needed before surgery, I felt uncomfortable about forcing Eric to do it, given the risks. He had made it clear that he wanted to proceed with surgery without delay or additional testing. He was willing to accept the risks of this approach. But his doctors refused to honor this request.

A patient’s right to self-determination is the prevailing ethic in medicine today, but in reality doctors routinely place limits on it. When a patient’s demand conflicts with a doctor’s moral convictions, ethicists have argued that doctors can deny treatment. For example, gynecologists can refuse to perform abortions because of moral or religious beliefs. Physicians in intensive care units routinely limit treatments they deem futile, especially for terminal illnesses.

But conscientious objection is a relatively rare impetus for denying treatment. A more common situation is when a patient’s request conflicts with what a doctor believes to be good medical practice. In such cases, the objection is over professional, not moral, integrity, though obviously moral questions are raised. In a doctor-patient dispute, who has the right to make the final call? Should doctors just do a patient’s bidding?

I have struggled with these questions from both sides of the doctor-patient relationship. When my wife was pregnant, she needed minor surgery. A surgeon offered us two options. The first posed no risk to our baby but for other reasons was unappealing. The more attractive alternative was slightly riskier, though our obstetrician told us that it was still safe, as long as sufficient oxygen was provided during the procedure. But an anesthesiologist, in pre-operative consultation, said he could not guarantee that would happen.

On the day of the surgery, a few minutes before my wife was to be taken into the operating room, a physician’s assistant demanded that she sign a consent form for the surgery she did not want. When she refused, the anesthesiologist, an imposing man with a bushy salt-and-pepper mustache and bulging eyes, threatened to cancel the operation.

“We would be getting away with something rather than doing the right thing,” he said of the surgical option we had chosen.

I tried to negotiate with him, but he would not budge. “Look, we’ll sign anything you want accepting the risk,” I told him.

He just laughed. “That is not the issue,” he replied. “We want her to be safe.”

“I am not the kind of doctor who says it has to be my way,” he had told us, but in fact, he was.

When I consulted an anesthesiologist at another hospital, she told me that she had polled her colleagues. About half said the procedure we wanted was safe. The remainder agreed with my wife’s anesthesiologist.

How should such disputes be resolved? In 1991, a Minnesota court ruled that the family of Helga Wanglie, an 86-year-old woman in a coma, had the right to demand intensive medical treatment for her, even though her physicians wanted to stop life support because they thought that it was futile. In that judgment, patient (or surrogate) autonomy trumped professional integrity.

Because patients are so dependent and vulnerable, I believe doctors should deny treatment requests only very judiciously — and rarely. A surgeon might understandably refuse to operate on someone whose religious beliefs proscribe blood transfusions, on the ground that she would not want to be forced into medical malpractice.

But in cases with reasonable differences of opinion, where the competing risks are at least debatable, it seems unfair and unwise to deny treatment. Was the reluctant anesthesiologist being virtuous or dogmatic? I’m still not sure. Professional integrity can indeed be a double-edge sword.

In the end, my wife went to another hospital. And Eric stayed and underwent a cerebral angiogram before valve surgery. Fortunately, both operations went well.

Epidemic of Drug Counterfeiting

Asia is seeing an ''epidemic of counterfeits'' of life-saving drugs, experts say, and the problem is spreading. Malaria medicines have been particularly hard hit; in a recent sampling in Southeast Asia, 53 percent of the antimalarials bought were fakes.

Bogus antibiotics, tuberculosis drugs, AIDS drugs and even meningitis vaccines have also been found.

Estimates of the deaths caused by fakes run from tens of thousands a year to 200,000 or more. The World Health Organization has estimated that a fifth of the one million annual deaths from malaria would be prevented if all medicines for it were genuine and taken properly.

''The impact on people's lives behind these figures is devastating,'' said Dr. Howard A. Zucker, the organization's chief of health technology and pharmaceuticals.

Internationally, a prime target of counterfeiters now is artemisinin, the newest miracle cure for malaria, said Dr. Paul N. Newton of Oxford University's Center for Tropical Medicine in Vientiane, Laos.

His team, which found that more than half the malaria drugs it bought in Southeast Asia were counterfeit, discovered 12 fakes being sold as artesunate pills made by Guilin Pharma of China.

A charity working in Myanmar bought 100,000 tablets and discovered that all were worthless.

''They're not being produced in somebody's kitchen,'' Dr. Newton said. ''They're produced on an industrial scale.''

China is the source of most of the world's fake drugs, experts say. In December, according to Xinhua, the state news agency, the former chief of China's Food and Drug Administration and two of his top deputies were arrested on charges of taking bribes to approve drugs.

The director, Zheng Xiaoyu, was in office from the agency's creation in 1998 until he was dismissed in 2005 after repeated scandals in which medicines and infant formula his agency had approved killed dozens of Chinese, including children.

''The problem is simply so massive that no amount of enforcement is going to stop it,'' said David Fernyhough, a counterfeiting expert at the Hong Kong offices of Hill & Associates, a risk-management firm hired by Western companies to foil counterfeiters.

The distribution networks, he said, ''mirror the old heroin networks,'' flowing to Thai distributors with financing and money-laundering arranged in Hong Kong. The penalties are less severe than for heroin.

Daniel C. K. Chow, an Ohio State University law professor and an expert on Chinese counterfeiting, said he believed that the authorities would pursue counterfeiters ''ruthlessly'' for killing Chinese citizens but be more lax about drugs for export.

''The counterfeiters aren't stupid,'' he said. ''They don't want anyone beating down the door in the middle of the night and dragging them away, so they make drugs for sale outside the country.''

A spokesman for the Chinese Embassy in Washington said that he had ''no idea'' whether most of the world's counterfeits came from China, but that Mr. Zheng's arrest proved China was cracking down. He also said counterfeiters would get the same punishment no matter whom they hurt.

Many of the fake artesunate pills found by Dr. Newton's team were startlingly accurate in appearance -- and much more devious in effect than investigators had suspected.

Not only did the pills look correct, as did the cardboard boxes, the blister packing and the foil backing, but investigators found 12 versions of the tiny hologram added to prevent forgery.

In one case, even a secret ''X-52'' logo visible only under ultraviolet light was present, though in the wrong spot.

Another hologram was forged by hand, Dr. Newton said, by someone who obviously spent hours with a pin and a magnifying glass making tiny dots on a circle of foil to imitate the shimmer.

But the most frightening aspect appeared when the pills were tested. Some contained harmless chalk, starch or flour. But the latest, he said, contained drugs apparently chosen to fool patients into thinking the pills were working.

Some had acetaminophen, which can temporarily lower malarial fevers but does not kill parasites. Some had chloroquine, an old and now nearly useless antimalarial.

In Japan’s Rural Areas, Remote Obstetrics Fills the Gap

Since losing its last obstetrician five years ago, this city of nearly 32,000 in rural northern Japan has been desperately seeking a replacement. So desperately, in fact, that it recently promised a horse to any obstetrician willing to come here.

When a patient in Tono goes into labor, she has to go to Kamaishi.

There have been no takers yet. In the meantime, the city has adopted a high-tech measure that may portend the future of child delivery in Japan: pregnant women are examined remotely by obstetricians using real-time data transmitted to the doctors’ cellphones. When the doctors judge that a patient is about to go into labor, the woman heads to the nearest city with a maternity ward — usually Kamaishi, a 40-minute drive east of here, reached by a winding, mountainous, two-lane road that can be treacherous in the winter.

Japan, with a rapidly aging population and a declining birth rate, is grappling with a severe shortage of working obstetricians and places for them to work. With a death of babies, hundreds of hospitals and clinics in Japan have shuttered their maternity wards since the beginning of the decade, turning their attention to potentially more lucrative elderly care.

Since 2000, the number of obstetricians in Japan has declined by more than 5 percent to 11,282 in 2004, the most recent year for which figures are available, according to the government. But that figure masks the severity of the shortage, experts say. The number of doctors actually delivering babies was fewer than 8,000 in 2005, according to an estimate by the Japan Society of Obstetrics and Gynecology.

Roughly half of all obstetricians are 50 or older, and overworked; many have given up delivering babies and are focusing only on gynecology. At the same time, the number of medical students choosing obstetrics as their specialty has plummeted since 2004. Turned off by long hours, average pay and a rising risk of malpractice lawsuits in obstetrics, young doctors are gravitating instead toward specialties like dermatology and ophthalmology.

“Young doctors nowadays won’t work just out of a sense of vocation,” said Dr. Kiyoo Tanabe, director of the Japan Association of Obstetricians and Gynecologists. “You have to give them quality of life, a good income and their private time.”

What is more, women make up a majority of obstetricians in their 20s and early 30s. Many retire when they themselves have children, Dr. Tanabe said, because the medical field remains unfriendly to working mothers.

The crisis, he said, “began in rural Japan and reached the major cities in the last year.”

Even in Tokyo, maternity wards are being closed or consolidated, creating a sense of anxiety among pregnant women who are warned to make an appointment for delivery as soon as they learn their due date.

“I was told that places where you can give birth are limited and that everybody is flocking to them,” said Eri Miyasato, 35, who is eight months pregnant and lives in a suburb of Tokyo. “You have to make an appointment for the delivery, and a lot of people are having trouble finding a place.”

Things have changed since the birth of her first child two and a half years ago. “Back then,” she said, “it was all right.”

But the hinterland has been hardest hit as maternity wards have closed one after another. The shortage is so severe that those obstetricians who still practice have few days off. In emergencies, women have been transported by helicopter to maternity wards with available beds. And some women who live far from a maternity ward, as their due dates approach, move to hotels near the hospitals where they are scheduled to give birth.

Tono, once a prosperous trading post known for its horse breeding, is an agricultural municipality that sprawls across a valley and is mostly forestland. As is the case in much of rural Japan, one-third of its residents are over 65.

Each year, 210 to 230 women have children here, said Eisai Kikuchi, a city health official. Since the prefectural hospital here closed its maternity ward in 2002, pregnant women have had no choice but to make the long drive to Kamaishi, or another city with a maternity ward, to give birth.

For Yukie Kikuchi, 38, the city’s sole practicing midwife, that has created worries. A year ago, during a snowstorm, one of Ms. Kikuchi’s patients wondered whether she was going into labor and asked the midwife whether she should go to Morioka, a city more than an hour away.

Drug Partnership Introduces Cheap Antimalaria Pill

A new, cheap, easy-to-take pill to treat malaria is being introduced today, the first product of an innovative partnership between an international drug company and a medical charity.

The medicine, called ASAQ, is a pill combining artemisinin, invented in China using sweet wormwood and hailed as a miracle malaria drug, with amodiaquine, an older drug that still works in many malarial areas.

A treatment will cost less than $1 for adults and less than 50 cents for children. Adults with malaria will take only two pills a day for three days, and the pill will come in three smaller once-a-day sizes for infants, toddlers and youngsters.

In Africa, malaria kills 3,000 babies and children each day, but combination drugs like this are not available for children under 11 pounds, and they require taking a larger number of pills each day, as many as 24 for some adult versions.

''This is a good thing,'' said Dr. Arata Kochi, chief of the World Health Organization's global malaria program, who has publicly demanded that drug companies stop making pills that contain artemisinin alone because they will lead to resistant strains of malaria. ''They're responding to the kind of drug profile we've been promoting.''

Doctors like to treat diseases with multidrug cocktails because it cuts down the chance that resistance to any one drug will develop.

Adm. R. Timothy Ziemer, coordinator of President Bush's $1.2 billion Malaria Initiative, said the program would be willing to buy the new pill, assuming it meets international safety standards and is requested by countries the initiative supports.

Sanofi-Aventis, the world's fourth-largest drug company, based in Paris, will sell the pill at cost to international health agencies like the W.H.O., Unicef and the Global Fund for AIDS, Tuberculosis and Malaria.

The rollout of the drug is the result of a two-year partnership between Sanofi and the Drugs for Neglected Diseases Initiative, a campaign started by the medical charity Doctors Without Borders to find new drugs for tropical diseases.

Doctors Without Borders, better known by its French name, Médecins Sans Frontières, has long been one of the harshest critics of the pharmaceutical industry, charging that it spent billions on drugs like Viagra, Ambien and Prozac for rich countries and almost nothing on diseases killing millions of poor people.

But, recognizing that new drugs would have to come from the industry's major players, Doctors Without Borders founded the initiative in 2003 and began seeking partnerships. This is the first to come to fruition.

''This was not a love wedding, it was a reasonable wedding,'' said Dr. Robert Sebbag, Sanofi's vice president for access to medicines. ''But reasonableness is often more important for a long marriage. They've seen we are not nasty people working against poor countries and seeking only profits.''

In an unusual move, Sanofi has decided not to seek any patents so the pills can be freely copied by generic companies like those in India. The drugs themselves are too old to patent, but the one-pill formulation could have been.

Sanofi will also produce a branded version, called Coarsucam, for the private market, to be sold at three or four times the public price. It will be sold only in Africa, Indonesia and the Philippines, the company said, not in the United States or Europe.

In another innovation, Sanofi will meet with pharmacists' organizations in poor countries and give them incentives to sell Coarsucam at two different prices -- at less than $1 to very poor customers and $3 to $4 to wealthier ones.

It will leave it to the pharmacists to estimate which of their customers lived on less than the cutoff income, which is about $40 a month, Dr. Sebbag said.

''Even in these countries, you always have some people who can pay,'' he said.

The company has already experimented with the idea in six African countries, from Mali to Kenya to Madagascar, when selling its previous version of the drug combination, which was separate pills of each drug in a blister pack.

Healthy women’s pneumonia risk not reduced by vitamins

Well-nourished women who get a lot of vitamins through their diet or supplements are at no less risk for community-acquired pneumonia than other women, a large prospective study suggests.

However, the study, which looked at more than 80,000 women, did find that smokers face a lower risk for pneumonia if their diet includes a lot of vitamin A.

Previous studies have found that specific vitamins lower people’s risk for pneumonia and respiratory infections, but most looked at elderly or malnourished individuals.

Mark Neuman (Children’s Hospital, Boston, Massachusetts, USA) and colleagues studied the effects of vitamin intake in 83,165 women from the Nurses’ Health Study II.

They focused on nurses who were 27–44 years of age in 1991, when the information on dietary and supplemental intake of vitamins was first collected.

Nutrient intake was assessed through self-administered questionnaires, and updated every 4 years.

The participants were followed-up for incident cases of community-acquired pneumonia for 10 years.

During 650,377 person-years of follow-up, 925 new cases of pneumonia were diagnosed. A case was considered to be physician-diagnosed pneumonia if confirmed by chest radiography.

In adjusted analyses, neither dietary nor total intake of any vitamin was associated with risk of community-acquired pneumonia.

These analyses adjusted for age, cigarette smoking, body mass index, physical activity, total energy intake, and alcohol consumption.

The vitamins studied included vitamins B12, A, C, D, and E, along with total carotenoids, alpha-carotene, beta-carotene, beta-cryptoxanthine, lycopene, lutein, and zeaxanthin.

However, when the researchers studied the association between vitamin intake and community-acquired pneumonia among smokers, they found a significant link.

After excluding smokers who took vitamin E supplements, they found that the risk of community-acquired pneumonia among women in the top quintile of dietary vitamin E intake was cut by more than half (relative risk [RR] = 0.45), compared with women in the lowest quintile.

Neuman et al conclude in the American Journal of Medicine: “Vitamin intake does not alter community-acquired pneumonia risk in healthy young and middle-aged women.

“Among smokers, higher intake of foods rich in vitamin E may reduce the risk of community-acquired pneumonia.”

Malaria

This infectious disease is caused by single-celled Plasmodium protists, including P. falciparum, P. vivax, P. malariae, and P. ovale. The parasites are usually transmitted from infected to noninfected people via the bite of female Anopheles mosquitoes; about 60 species of Anopheles can serve as vectors. The parasites take up residence in the victim's red blood cells.

The disease is characterized by episodes of chills and fever followed by profuse sweating; shaking and fatigue are other common symptoms. Repeated bouts can result in severe anemia, dehydration, and death. Infants, children, and pregnant women are at greatest risk of severe illness and death.

Treatment with chloroquine or other drugs that kill the Plasmodium has become more difficult in recent years. The parasites have become resistant to the drugs, and the Anopheles mosquitoes have become resistant to insecticides. Efforts to produce a malaria vaccine have been extensive but unsuccessful.

Malaria is most common in tropical and subtropical lands, particularly sub- Saharan Africa and Southeast Asia. It is both a cause of poverty and a result of poverty. Each year, between 300 million and 500 million acute cases are diagnosed and 1.5 million to 2.7 million people die of the disease. Almost all of the approximately 1,000 Americans who contract malaria each year get the disease while traveling abroad.

Study Identifies 'braking' Mechanism In The Brain

As wise as the counsel to "finish what you've started" may be, it is also sometimes critically important to do just the opposite -- stop. And the ability to stop quickly, to either keep from gunning the gas when a pedestrian steps into your path or to bite your tongue mid-sentence when the subject of gossip suddenly comes into view, may depend on a few "cables" in the brain.

Researchers led by cognitive neuroscientist Adam Aron, an assistant professor of psychology at the University of California, San Diego, have found white matter tracts -- bundles of neurons, or "cables," forming direct, high-speed connections, between distant regions of the brain -- that appear to play a significant role in the rapid control of behavior.

Published in the April 4 issue of the Journal of Neuroscience, the study is the first to identify these white matter tracts in humans, confirming similar findings in monkeys, and the first to relate them to the brain's activity while people voluntarily control their movements.

"Our results provide important information about the correspondence between the anatomy and the activity of control circuits in the brain," Aron said. "We've known for some time about key brain areas involved in controlling behavior and now we're learning how they're connected and how it is that the information can get from one place to the other really fast."

"The findings could be useful not only for understanding movement control," Aron said, "but also 'self-control' and how control functions are affected in a range of neuropsychiatric conditions such as addiction, Tourette's syndrome, stuttering and Attention Deficit Hyperactivity Disorder."

To reveal the network, Aron and researchers from UCLA, Oxford University and the University of Arizona performed two types of neuroimaging scan on healthy volunteers.

They used diffusion-weighted MRI, in 10 subjects, to demonstrate the "cables" between distant regions of the brain known to be important for control, and they used functional MRI, in 15 other subjects, to show that these same regions were activated when participants stopped their responses on a simple computerized "go-stop" task.

One of the connected regions was the subthalamic nucleus, within the deep-seated midbrain, which is an interface with the motor system and can be considered a "stop button" or the brake itself. A second region was in the right inferior frontal cortex, a region near the temple, where the control signal to put on the brakes probably comes from.

"This begs the profound question," Aron said, "of where and how the decision to execute control arises."

While this remains a mystery, Aron noted that an additional, intriguing finding of the study was that the third connected node in the network was the presupplementary motor area, which is at the top of the head, near the front. Prior research has implicated this area in sequencing and imagining movements, as well as monitoring for changes in the environment that might conflict with intended actions.

The braking network for movements may also be important for the control of our thoughts and emotions.

There is some evidence for this, Aron said, in the example of Parkinson's patients. In the advanced stages of disease, people can be completely frozen in their movements, because, it seems, their subthalamic nucleus, or stop button, is always "on." While electrode treatment of the area unfreezes the patients' motor system, it can also have the curious effect of disinhibiting them in other ways. In one case, an upstanding family man became manic and hypersexual, and suddenly began stealing money from his wife to pay for prostitutes.

Examples like these motivate Aron to investigate the generality of the braking mechanism.

"The study gives us new targets for studying how the brain relates to behavior, personality and genetics," Aron said. "Variability in the density and thickness of the 'cable' connections is probably influenced by genes, and it would be intriguing if these differences explained people's differing abilities not only to control the swing of a bat but also to control their temper."