Tuesday, September 28, 2010
Magnetic pulses can sway the hand you use, briefly
NEW YORK | Tue Sep 28, 2010
Whether your left or right hand reaches for the phone, elevator button or cup of coffee is typically decided unconsciously. Now, a new study suggests that magnetic pulses sent into your brain could alter that choice.
The finding is preliminary, but it brings to mind past efforts to "correct" the handedness of lefty children. In Germany, for example, such "conversions" were standard practice until the 1970s, according to Dr. Stefan Kloppel of the University of Freiburg.
Kloppel, who has studied how the brain makes these decisions, was not involved in the current study and noted that such conversion is no longer recommended.
"People make this decision many, many times throughout the day," lead researcher Flavio Oliveira of University of California, Berkeley, told Reuters Health, speaking of the choice of which hand to use for a particular task, not handedness conversions. "We wanted to explore how this process emerges in the brain, and which parts of the brain are involved."
Hand preference is known to be influenced by past experience and the current position of the hands in relation to the target. But just how the decision process is carried out remains unclear.
Alien hand syndrome, a curious condition in which people report losing conscious control over one of their limbs, inspires one possible explanation.
"Often when a patient reaches out with one hand toward an object, the other hand follows, and they will deny attempting that movement," said Oliveira. "Maybe this is some evidence to suggest that there is a competition that occurs in the brain."
"For example, in healthy individuals, once one hand wins the competition it inhibits the other," he explained. "But in these patients, maybe that doesn't happen."
To see if the idea held, Oliveira and his colleagues put 33 people, all right-handed, through a series of experiments. Each round, participants were presented with an object at varying locations on a table and told to reach for it as quickly as possible.
Participants showed an overall strong-hand bias, targeting objects midway between their hands more frequently with the right hand until about 15 degrees left of the mid-point.
Compared to reaching for objects positioned at right and left extremes, reaction times were longer for objects closer to the center, report the researchers in the Proceedings of the National Academy of Sciences.
When they stimulated the left posterior parietal cortex with magnetic pulses, temporarily disrupting activity in this region of the brain's left hemisphere, participants were more apt to reach with their left hand than they had during previous rounds without stimulation. In fact, when objects were positioned in the ambiguous middle territory, they used their left an average of 14 percent more often than they had earlier.
No significant changes were seen in hand preference when the corresponding right part of the brain was stimulated.
"We found that we could modify people's preference," Oliveira noted, and this "gave us strong evidence that there was this competition going on."
In other words, the brain might be simultaneously devising action plans for each hand until one hits a threshold and is actually performed. "You can think of it like a race between two horses," he added. "With stimulation, you're handicapping one of the horses -- slowing it down such that the other has a better chance to win. So in situations where the horse running for the right hand would normally win, we're slowing it down a little bit so that the horse for left hand wins more often."
While well done, Kloppel said the study was not enough to suggest a way to "convert" left-handers - and that such conversions are no longer recommended anyway.
"I think the study by Oliveira provides convincing evidence for the role of the left posterior parietal cortex in hand choice. A study on left-handers would be required to conclude a possible role when converting left-handers," Kloppel said.
Further, he added that the current study was concerned with hand choice in ambiguous situations: "These differ from most tasks that are used to define handedness, such as writing or using a toothbrush, where the choice of hand should be stable."
Whether your left or right hand reaches for the phone, elevator button or cup of coffee is typically decided unconsciously. Now, a new study suggests that magnetic pulses sent into your brain could alter that choice.
The finding is preliminary, but it brings to mind past efforts to "correct" the handedness of lefty children. In Germany, for example, such "conversions" were standard practice until the 1970s, according to Dr. Stefan Kloppel of the University of Freiburg.
Kloppel, who has studied how the brain makes these decisions, was not involved in the current study and noted that such conversion is no longer recommended.
"People make this decision many, many times throughout the day," lead researcher Flavio Oliveira of University of California, Berkeley, told Reuters Health, speaking of the choice of which hand to use for a particular task, not handedness conversions. "We wanted to explore how this process emerges in the brain, and which parts of the brain are involved."
Hand preference is known to be influenced by past experience and the current position of the hands in relation to the target. But just how the decision process is carried out remains unclear.
Alien hand syndrome, a curious condition in which people report losing conscious control over one of their limbs, inspires one possible explanation.
"Often when a patient reaches out with one hand toward an object, the other hand follows, and they will deny attempting that movement," said Oliveira. "Maybe this is some evidence to suggest that there is a competition that occurs in the brain."
"For example, in healthy individuals, once one hand wins the competition it inhibits the other," he explained. "But in these patients, maybe that doesn't happen."
To see if the idea held, Oliveira and his colleagues put 33 people, all right-handed, through a series of experiments. Each round, participants were presented with an object at varying locations on a table and told to reach for it as quickly as possible.
Participants showed an overall strong-hand bias, targeting objects midway between their hands more frequently with the right hand until about 15 degrees left of the mid-point.
Compared to reaching for objects positioned at right and left extremes, reaction times were longer for objects closer to the center, report the researchers in the Proceedings of the National Academy of Sciences.
When they stimulated the left posterior parietal cortex with magnetic pulses, temporarily disrupting activity in this region of the brain's left hemisphere, participants were more apt to reach with their left hand than they had during previous rounds without stimulation. In fact, when objects were positioned in the ambiguous middle territory, they used their left an average of 14 percent more often than they had earlier.
No significant changes were seen in hand preference when the corresponding right part of the brain was stimulated.
"We found that we could modify people's preference," Oliveira noted, and this "gave us strong evidence that there was this competition going on."
In other words, the brain might be simultaneously devising action plans for each hand until one hits a threshold and is actually performed. "You can think of it like a race between two horses," he added. "With stimulation, you're handicapping one of the horses -- slowing it down such that the other has a better chance to win. So in situations where the horse running for the right hand would normally win, we're slowing it down a little bit so that the horse for left hand wins more often."
While well done, Kloppel said the study was not enough to suggest a way to "convert" left-handers - and that such conversions are no longer recommended anyway.
"I think the study by Oliveira provides convincing evidence for the role of the left posterior parietal cortex in hand choice. A study on left-handers would be required to conclude a possible role when converting left-handers," Kloppel said.
Further, he added that the current study was concerned with hand choice in ambiguous situations: "These differ from most tasks that are used to define handedness, such as writing or using a toothbrush, where the choice of hand should be stable."
Exercise has lasting benefits for older women
NEW YORK | Tue Sep 28, 2010
Older women with thinning bones who exercise regularly have sustained improvements in their balance and walking speed that may protect them from fractures and even extend their lives, new research shows.
The researchers found that just 20 minutes of at-home exercise daily, interspersed with six months of supervised weekly training every year, over the course of five years helped increase women's gait stability and cut their risk of fracture by 32 percent.
The improvements persisted for two years after the exercise program ended, with exercisers also being at lower risk of sustaining hip fractures or dying during follow-up, Dr. Raija Korpelainen of the department of sports and exercise medicine at Oulu Deaconess Institute in Oulu, Finland, and colleagues found.
While exercise has been shown to help prevent falls in healthy older people, Korpelainen and colleagues note in the Archives of Internal Medicine, less information is available on the effectiveness of exercise for older women with the bone-thinning disease osteoporosis.
The researchers had originally conducted a 30-month trial of an exercise intervention in 160 women with osteopenia, meaning they had some loss of bone density but not enough to constitute osteoporosis. They found that the women who exercised walked more quickly and performed better on other measures of strength and stability than the women who didn't exercise. In the current study, they report on a seven-year follow-up of participants in that study.
Fifty-five women in the exercise group and 45 in the control group were available for the final follow-up measurements. During follow-up, 17 hospital-treated fractures occurred in the exercisers, compared to 23 in the control group. None of the women in the exercise group had hip fractures during follow-up, while there were five hip fractures among the control group women.
Among all the women in the study, those who had engaged in moderate physical activity throughout their lives were 78 percent less likely to sustain a fracture during follow-up.
While the exercisers had maintained their baseline walking speed over the course of the follow-up period, the control group showed a significant decline over time. But both groups saw a similar decline in bone mineral density during follow-up.
One of the exercise group participants, representing 1.2 percent of the follow-up group, had died seven years into the study, compared to eight, or 10.5 percent, of the control group. But the small size of the study, the researchers say, "limits the conclusions that can be drawn" about whether exercise actually reduced mortality.
The researchers also note that fractures in the control group were located closer to the core of the body (for example, in a hip rather than a knee) than the fractures in the exercise group, "indicating that the type of fall may have been different in the exercisers."
The improvements seen in gait and other measurements of physical capacity in the exercise group may have allowed them to fall in a way that was less likely to result in serious injury, they suggest.
Even small declines in strength and stability can significantly impair older people's ability to perform activities of daily living, such as getting out of bed, the researchers note. "Many elderly people live just beyond the threshold of the capacity needed for such tasks," they add. "These results suggest that these women may have had an increase in performance capacity reserve large enough to prevent loss of independence and future fractures."
"Regular daily physical exercise," the researchers conclude, "should be recommended to elderly women with osteopenia."
Older women with thinning bones who exercise regularly have sustained improvements in their balance and walking speed that may protect them from fractures and even extend their lives, new research shows.
The researchers found that just 20 minutes of at-home exercise daily, interspersed with six months of supervised weekly training every year, over the course of five years helped increase women's gait stability and cut their risk of fracture by 32 percent.
The improvements persisted for two years after the exercise program ended, with exercisers also being at lower risk of sustaining hip fractures or dying during follow-up, Dr. Raija Korpelainen of the department of sports and exercise medicine at Oulu Deaconess Institute in Oulu, Finland, and colleagues found.
While exercise has been shown to help prevent falls in healthy older people, Korpelainen and colleagues note in the Archives of Internal Medicine, less information is available on the effectiveness of exercise for older women with the bone-thinning disease osteoporosis.
The researchers had originally conducted a 30-month trial of an exercise intervention in 160 women with osteopenia, meaning they had some loss of bone density but not enough to constitute osteoporosis. They found that the women who exercised walked more quickly and performed better on other measures of strength and stability than the women who didn't exercise. In the current study, they report on a seven-year follow-up of participants in that study.
Fifty-five women in the exercise group and 45 in the control group were available for the final follow-up measurements. During follow-up, 17 hospital-treated fractures occurred in the exercisers, compared to 23 in the control group. None of the women in the exercise group had hip fractures during follow-up, while there were five hip fractures among the control group women.
Among all the women in the study, those who had engaged in moderate physical activity throughout their lives were 78 percent less likely to sustain a fracture during follow-up.
While the exercisers had maintained their baseline walking speed over the course of the follow-up period, the control group showed a significant decline over time. But both groups saw a similar decline in bone mineral density during follow-up.
One of the exercise group participants, representing 1.2 percent of the follow-up group, had died seven years into the study, compared to eight, or 10.5 percent, of the control group. But the small size of the study, the researchers say, "limits the conclusions that can be drawn" about whether exercise actually reduced mortality.
The researchers also note that fractures in the control group were located closer to the core of the body (for example, in a hip rather than a knee) than the fractures in the exercise group, "indicating that the type of fall may have been different in the exercisers."
The improvements seen in gait and other measurements of physical capacity in the exercise group may have allowed them to fall in a way that was less likely to result in serious injury, they suggest.
Even small declines in strength and stability can significantly impair older people's ability to perform activities of daily living, such as getting out of bed, the researchers note. "Many elderly people live just beyond the threshold of the capacity needed for such tasks," they add. "These results suggest that these women may have had an increase in performance capacity reserve large enough to prevent loss of independence and future fractures."
"Regular daily physical exercise," the researchers conclude, "should be recommended to elderly women with osteopenia."
Acupuncture not helpful for stroke recovery
NEW YORK | Tue Sep 28, 2010
Acupuncture does not help speed recovery after stroke, according to an analysis of 10 trials using fake or "sham" acupuncture as a control.
"Our meta-analysis of data from rigorous randomized sham-controlled trials did not show a positive effect of acupuncture as a treatment for functional recovery after stroke," Dr. Jae Cheol Kong of Wonkwang University in Iksan, South Korea, and colleagues conclude in the Canadian Medical Association Journal (CMAJ).
Some recent studies have found no benefit for acupuncture when it is compared to sham acupuncture, a placebo version of the traditional Chinese medicine technique that can involve needling non-acupuncture points, penetrating the skin shallowly, or not penetrating the skin at all.
For example, recent studies found acupuncture was not effective for inducing labor, while another showed no benefit of the traditional Chinese technique for improving the success of in vitro fertilization (IVF).
While several reviews of the medical literature on acupuncture for stroke recovery have been published, the authors of the current study note, many have had limitations, for example failing to include studies published in Asian countries.
To address this issue, Kong and colleagues searched 25 databases and 12 Korean traditional medicine journals. Among 664 studies on the topic, the researchers found 10 that met their criteria, including 711 patients in all.
Two of the trials compared real acupuncture to sham electrostimulation, while the other eight used sham acupuncture as a placebo. Several different analyses of the trials found acupuncture did not improve patients' ability to perform activities of daily living, nor did it show improvement in measurements of neurological function. While two studies did find a benefit for acupuncture, "poor reporting and high risks of bias rendered both studies less than reliable," Kong and colleagues write.
The researchers acknowledge that sham acupuncture may not be a true placebo, and could actually be producing physiological effects, which could explain the lack of difference between the fake and real acupuncture groups. Other "drawbacks" to their findings include the lack of data and the often-poor quality of that data, they add.
In an editorial accompanying the study, Dr. Hongmei Wu of West China Hospital in Chengdu argues that given the small size of the studies, as well as the fact that sham acupuncture may actually have some effect, "it is premature to refute the effects of acupuncture in treatment of stroke rehabilitation."
"Rigorously designed, large, multicentre randomized trials are needed to assess the effects of acupuncture on stroke rehabilitation further," Wu concludes.
Acupuncture does not help speed recovery after stroke, according to an analysis of 10 trials using fake or "sham" acupuncture as a control.
"Our meta-analysis of data from rigorous randomized sham-controlled trials did not show a positive effect of acupuncture as a treatment for functional recovery after stroke," Dr. Jae Cheol Kong of Wonkwang University in Iksan, South Korea, and colleagues conclude in the Canadian Medical Association Journal (CMAJ).
Some recent studies have found no benefit for acupuncture when it is compared to sham acupuncture, a placebo version of the traditional Chinese medicine technique that can involve needling non-acupuncture points, penetrating the skin shallowly, or not penetrating the skin at all.
For example, recent studies found acupuncture was not effective for inducing labor, while another showed no benefit of the traditional Chinese technique for improving the success of in vitro fertilization (IVF).
While several reviews of the medical literature on acupuncture for stroke recovery have been published, the authors of the current study note, many have had limitations, for example failing to include studies published in Asian countries.
To address this issue, Kong and colleagues searched 25 databases and 12 Korean traditional medicine journals. Among 664 studies on the topic, the researchers found 10 that met their criteria, including 711 patients in all.
Two of the trials compared real acupuncture to sham electrostimulation, while the other eight used sham acupuncture as a placebo. Several different analyses of the trials found acupuncture did not improve patients' ability to perform activities of daily living, nor did it show improvement in measurements of neurological function. While two studies did find a benefit for acupuncture, "poor reporting and high risks of bias rendered both studies less than reliable," Kong and colleagues write.
The researchers acknowledge that sham acupuncture may not be a true placebo, and could actually be producing physiological effects, which could explain the lack of difference between the fake and real acupuncture groups. Other "drawbacks" to their findings include the lack of data and the often-poor quality of that data, they add.
In an editorial accompanying the study, Dr. Hongmei Wu of West China Hospital in Chengdu argues that given the small size of the studies, as well as the fact that sham acupuncture may actually have some effect, "it is premature to refute the effects of acupuncture in treatment of stroke rehabilitation."
"Rigorously designed, large, multicentre randomized trials are needed to assess the effects of acupuncture on stroke rehabilitation further," Wu concludes.
AIDS treatment up in 2009; 2010 targets in doubt: WHO
NAIROBI | Tue Sep 28, 2010
A total of 5.25 million people were receiving antiretroviral therapy in 2009, three-quarters of them in Africa, WHO said in a report co-authored with U.N. children's fund UNICEF and UNAIDS.
"Millions of people are alive today as a result of investments in HIV over the past few years," it said, reporting success in "reducing new infections, averting deaths and ensuring that people living with HIV enjoy healthy lives."
The report said eight low and middle income countries -- Botswana, Cambodia, Croatia, Cuba, Guyana, Oman, Romania and Rwanda -- met the goal of giving treatment to at least 80 per cent of patients in need in 2009, well ahead of the end-2010 deadline agreed by world leaders in 2006.
However, global targets for HIV prevention, treatment, care and support are unlikely to be reached in 2010, it said.
NOT THERE YET
Only a third of people who need antiretroviral therapy are receiving it and less than 40 percent of people living with HIV know their status.
"In many parts of our continent there is not really any great incentive for knowing your HIV status," Mohamed Ibrahim, Director of Kenya's National AIDS/STD Control Program, told a news conference while launching the report in Nairobi.
"Stigma and discrimination unfortunately is still very high."
After 15 years of increased support for HIV/AIDS programs, funding stagnated due to the global economic crisis. In 2009, commitments from donor governments totaled $8.7 billion, equal to that in 2008.
National testing campaigns have proven successful in several African countries like Burkina Faso, Malawi, Kenya and Tanzania. South Africa has launched the world's largest HIV testing campaign, aiming to test 15 million people by June 2011.
"It is clear that without continued and strengthened financial and programmatic commitments, there is considerable danger that these achievements could be undone," the report said.
There is likely to be a funding gap of around $10 billion this year, David Okello, director of the WHO regional office for Africa, said.
The Global Fund to Fight AIDS, Tuberculosis and Malaria will hold a conference in New York on October 4-5 in which it is seeking between $17 and $20 billion in pledges between 2011 and 2013.
Hundreds of Kenyan campaigners marched through the streets of the capital Tuesday to demand more funding.
"The donors' pledges are woefully inadequate," Paul Davis of the Health Global Access Project told Reuters during the march.
Monday, September 27, 2010
Genetic discovery could lead to brain treatments
LONDON | Mon Sep 27, 2010 4:35am IST
British scientists have discovered a genetic mechanism in the development of the nervous system that they say might one day be part of new treatments for stroke, Alzheimer's disease or brain tumors.
In a study in the journal Nature Neuroscience, the scientists found that a gene, named Sox9, is key to the development of neural stem cells in the human embryo -- master cells that in turn develop into brain or spinal tissue.
In experiments in mice, they found that by using the gene they could kick-start the development of these cells, raising the prospect of one day being able to replace or regenerate damaged brain cells in humans.
"With the knowledge that the gene Sox9 plays a central role in the development of our nervous system, we are one step closer to being able to control stem cells in the brain and regenerate different kinds of nerve cells," said James Briscoe from Britain's Medical Research Council, who led the study.
"Being able to correct damaged nerve cells would be a huge leap forward for the millions of people with Alzheimer's, stem cell-related brain tumors or who have suffered from a stroke," he said in a statement, although it is likely to be many more years before such treatments for humans are developed.
Human embryos begin to develop their nervous systems just after two weeks from conception, the researchers explained.
From this stage until about five weeks, the nervous system is largely made up of so-called neuroepithelial cells, which grow rapidly and lay the foundations for brains and spinal cord.
It is only after this stage that the various types of nerves and supporting cells that make up the central nervous system begin to appear. These come from stem cells.
In their study, Briscoe's team found that Sox9 is needed for the neuroepithelial cells to turn into these stem cells.
It also continues to be needed to allow stem cells in the adult brain to retain their properties, such as the ability to self-renew and differentiate.
The scientists also found that a gene known as Shh is needed for Sox9 to work.
By artificially adding Sox9 or Shh to neuroepithelial cells in mouse embryos, they found they were able to kick-start the process of converting them into neural stem cells.
They also found that if there was a genetic defect in Sox9, it was much harder for the mice in their experiments to be able to renew damaged nerve cells later on.
The potential of different kinds of stem cells is being examined by experts around the world for many diseases. But the technology is controversial, in part because some stem cell lines are derived from embryos or foetuses.
Sanofi says holds offer for Genzyme at $69/share
PARIS | Mon Sep 27, 2010 1:13pm IST
(Reuters) - Sanofi-Aventis has not changed its offer of $69 per share for drugmaker Genzyme, a Sanofi spokesman said Monday, declining to comment on a report that the drugmaker had lined up more financing for its bid.
"We have one offer at $69. No other offer has been made ... We would like to enter into a dialogue," said Sanofi spokesman Jean-Marc Podvin.
He declined to comment on a Wall Street Journal report released over the weekend that said Sanofi-Aventis had lined up more financing from Citigroup and Bank of America Corp.
Sanofi has said it already has financing from J.P. Morgan Chase & Co, BNP Paribas SA and Societe Generale SA.
The French drugmaker wants to reach a friendly agreement but has not ruled out a hostile offer made directly to Genzyme shareholders, sources previously told Reuters.
Last month, Genzyme rejected Sanofi's $69 per share offer as dramatically undervaluing the U.S. company and not a bid that justified entering merger talks.
Sources previously told Reuters that Genzyme sought an offer of at least $75 per share before Sanofi could review its books, while some investors want up to $80 a share in a deal. Sanofi wants to buy Genzyme, a leading maker of drugs for rare diseases, to fuel growth as some of its key treatments lose patent protection.
(Reuters) - Sanofi-Aventis has not changed its offer of $69 per share for drugmaker Genzyme, a Sanofi spokesman said Monday, declining to comment on a report that the drugmaker had lined up more financing for its bid.
"We have one offer at $69. No other offer has been made ... We would like to enter into a dialogue," said Sanofi spokesman Jean-Marc Podvin.
He declined to comment on a Wall Street Journal report released over the weekend that said Sanofi-Aventis had lined up more financing from Citigroup and Bank of America Corp.
Sanofi has said it already has financing from J.P. Morgan Chase & Co, BNP Paribas SA and Societe Generale SA.
The French drugmaker wants to reach a friendly agreement but has not ruled out a hostile offer made directly to Genzyme shareholders, sources previously told Reuters.
Last month, Genzyme rejected Sanofi's $69 per share offer as dramatically undervaluing the U.S. company and not a bid that justified entering merger talks.
Sources previously told Reuters that Genzyme sought an offer of at least $75 per share before Sanofi could review its books, while some investors want up to $80 a share in a deal. Sanofi wants to buy Genzyme, a leading maker of drugs for rare diseases, to fuel growth as some of its key treatments lose patent protection.
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