PARIS: An experimental drug tested on lab animals has shown remarkable success in tackling two viruses, including a close cousin to a feared bioterror pathogen, a study said.
The drug, bavituximab, takes a novel tack in confronting viruses, which are notorious for mutations that evade or resist conventional pharmaceutical molecules. Instead of confronting the intruder head-on, bavituximab waits until the virus has infected the cell.
At that point, a fatty molecule called phosphatidylserine, which is normally positioned on the cell wall’s internal surface, flips to the outside of the cell.
Bavituximab then latches onto the phosphatidylserine, sending a red flag to the body’s immune system to dispatch white blood cells to destroy the infected cell. In a study in Nature Medicine, bavituximab was put through its paces among guinea pigs infected with Pichinde virus — a close relative of the Lassa fever virus, considered a potential bioterror weapon by the Pentagon.
Animals that had not been inoculated with bavituximab were all killed; those who had received the injection had a 50% survival rate. By giving the bavituximab group an additional injection with a standard anti-virus drug called ribavirin, the survival rate rose to 63%. The drug also provided 100% protection amongst mice exposed to a virus called cytomegalovirus, whereas only 25% of untreated animals survived.
Co-author Philip Thorpe, a professor of pharmacology at UT Southwestern Medical Center in Texas, said the findings were exciting, for they raised the prospect of a “completely new class” of anti-viral drugs that may also sidestep the problem of mutation. “By targeting a property of the host cell rather than the virus itself, anti-PS [phosphatidylserine] antibodies have the potential to treat a range of viral infections,” he said.
Oceans 'turning acidic quickly'
WASHINGTON: In a new research, scientists at the University of Chicago, US, have documented that oceans are growing acidic faster than previously thought.
In addition, they have found that the increasing acidity correlates with increasing levels of atmospheric carbon dioxide (CO2).
"Of the variables the study examined that are linked to changes in ocean acidity, only atmospheric carbon dioxide exhibited a corresponding steady change," said J. Timothy Wootton, the lead author of the study and Professor of Ecology and Evolution at the University of Chicago.
The increasingly acidic water harms certain sea animals and could reduce the ocean's ability to absorb carbon dioxide, according to the researchers.
Scientists have long predicted that higher levels of atmospheric carbon dioxide would make the ocean more acidic.
Nevertheless, empirical evidence of growing acidity has been limited.
The new study is based on 24,519 measurements of ocean pH spanning eight years, which represents the first detailed dataset on variations of coastal pH at a temperate latitude, where the world's most productive fisheries live.
"The acidity increased more than 10 times faster than had been predicted by climate change models and other studies," Wootton said.
"This increase will have a severe impact on marine food webs and suggests that ocean acidification may be a more urgent issue than previously thought, at least in some areas of the ocean," he added.
The ocean plays a significant role in global carbon cycles. When atmospheric carbon dioxide dissolves in water it forms carbonic acid, increasing the acidity of the ocean.
During the day, carbon dioxide levels in the ocean fall because photosynthesis takes it out of the water, but at night, levels increase again.
The study documented this daily pattern, as well as a steady increase in acidity over time.
"Many sea creatures have shells or skeletons made of calcium carbonate, which the acid can dissolve," said Catherine Pfister, associate professor of ecology and evolution at the University of Chicago and a co-author of the study.
"Therefore, the increased acidity of the ocean could interfere with many critical ocean processes such as coral reef building or shellfish harvesting," she added.
In addition, they have found that the increasing acidity correlates with increasing levels of atmospheric carbon dioxide (CO2).
"Of the variables the study examined that are linked to changes in ocean acidity, only atmospheric carbon dioxide exhibited a corresponding steady change," said J. Timothy Wootton, the lead author of the study and Professor of Ecology and Evolution at the University of Chicago.
The increasingly acidic water harms certain sea animals and could reduce the ocean's ability to absorb carbon dioxide, according to the researchers.
Scientists have long predicted that higher levels of atmospheric carbon dioxide would make the ocean more acidic.
Nevertheless, empirical evidence of growing acidity has been limited.
The new study is based on 24,519 measurements of ocean pH spanning eight years, which represents the first detailed dataset on variations of coastal pH at a temperate latitude, where the world's most productive fisheries live.
"The acidity increased more than 10 times faster than had been predicted by climate change models and other studies," Wootton said.
"This increase will have a severe impact on marine food webs and suggests that ocean acidification may be a more urgent issue than previously thought, at least in some areas of the ocean," he added.
The ocean plays a significant role in global carbon cycles. When atmospheric carbon dioxide dissolves in water it forms carbonic acid, increasing the acidity of the ocean.
During the day, carbon dioxide levels in the ocean fall because photosynthesis takes it out of the water, but at night, levels increase again.
The study documented this daily pattern, as well as a steady increase in acidity over time.
"Many sea creatures have shells or skeletons made of calcium carbonate, which the acid can dissolve," said Catherine Pfister, associate professor of ecology and evolution at the University of Chicago and a co-author of the study.
"Therefore, the increased acidity of the ocean could interfere with many critical ocean processes such as coral reef building or shellfish harvesting," she added.
Herpes drug inhibits HIV replication
WASHINGTON: Anti-herpes drug acyclovir can slow down HIV infection by targeting an enzyme, but is also instrumental in the emergence of multi-drug
resistant HIV variants.
HIV and herpes (HSV) are two of the most common sexually transmitted diseases worldwide, and individuals frequently become infected with both.
In such cases, the two viruses interact with each other; the presence of HIV often results in more frequent HSV lesion outbreaks, while HSV can speed up the progression of HIV to AIDS.
Considering their interaction, recent studies showing that acyclovir treatment could reduce HIV viral load in co-infected patients were not surprising, and attributed to an indirect effect of HSV suppression.
However, Moira McMahon and colleagues at Johns Hopkins decided to look whether the effects on HIV might be direct.
They used a sensitive infection assay of white blood cells and found that acyclovir can directly inhibit HIV replication, the medical school said in a statement. The drug specifically targeted RT, the key HIV enzyme that converts the virus' RNA into DNA so it can be replicated.
However, acyclovir treatment had some unexpected results; five days after initial infection, a mutant version of HIV (V75I) appeared in the cells, and within 94 days spread to comprise over 90 percent of the viral population.
The V75I strain is part of the resistance pathway to many drugs, including the commonly used RT inhibitors. What this means, the authors note, is that acyclovir could be a great model for designing future HIV treatments, but also could be a risky drug if given to HSV patients co-infected with HIV by potentially promoting cross-resistance to current treatments.
resistant HIV variants.
HIV and herpes (HSV) are two of the most common sexually transmitted diseases worldwide, and individuals frequently become infected with both.
In such cases, the two viruses interact with each other; the presence of HIV often results in more frequent HSV lesion outbreaks, while HSV can speed up the progression of HIV to AIDS.
Considering their interaction, recent studies showing that acyclovir treatment could reduce HIV viral load in co-infected patients were not surprising, and attributed to an indirect effect of HSV suppression.
However, Moira McMahon and colleagues at Johns Hopkins decided to look whether the effects on HIV might be direct.
They used a sensitive infection assay of white blood cells and found that acyclovir can directly inhibit HIV replication, the medical school said in a statement. The drug specifically targeted RT, the key HIV enzyme that converts the virus' RNA into DNA so it can be replicated.
However, acyclovir treatment had some unexpected results; five days after initial infection, a mutant version of HIV (V75I) appeared in the cells, and within 94 days spread to comprise over 90 percent of the viral population.
The V75I strain is part of the resistance pathway to many drugs, including the commonly used RT inhibitors. What this means, the authors note, is that acyclovir could be a great model for designing future HIV treatments, but also could be a risky drug if given to HSV patients co-infected with HIV by potentially promoting cross-resistance to current treatments.
Migraine reduces breast cancer risk
CHICAGO: In a puzzling twist, women who have a history of migraine headaches are far less likely to develop breast cancer than other women, US
researchers said on Thursday.
The study is the first to look at the relationship between breast cancer and migraine and its findings may point to new ways of reducing a woman’s breast cancer risk, they said. “We found that, overall, women who had a history of migraine had a 30% lower risk of breast cancer compared to women who did not have a history of such headaches,” said Christopher Li of the Fred Hutchinson Cancer Research Center in Seattle. Li said the reduction in risk was for the most common types of breast cancers — those driven by hormones. Hormones also play a role in migraine.
researchers said on Thursday.
The study is the first to look at the relationship between breast cancer and migraine and its findings may point to new ways of reducing a woman’s breast cancer risk, they said. “We found that, overall, women who had a history of migraine had a 30% lower risk of breast cancer compared to women who did not have a history of such headaches,” said Christopher Li of the Fred Hutchinson Cancer Research Center in Seattle. Li said the reduction in risk was for the most common types of breast cancers — those driven by hormones. Hormones also play a role in migraine.
Brain tissue created from stem cells
TOKYO: Japanese researchers said on Thursday they had created functioning human brain tissue from stem cells, a world first that has raised new
hopes for the treatment of disease.
Stem cells taken from human embryos have been used to form tissues of the cerebral cortex, the supreme control tower of the brain, according to experts at the government-backed research institute Riken. The tissues self-organised into four distinct zones very similar to the structure seen in human foetuses, and conducted neuro-activity such as transmitting electrical signals.
Research on stem cells is seen as having the potential to save lives by helping to find cures for diseases such as cancer and diabetes or to replace damaged cells, tissues and organs. The team’s previous studies showed stem cells differentiated into distinct cells but until now they had never organised into functioning tissues.
“In regenerative therapy, only a limited number of diseases can be cured with simple cell transplants. Transplanting tissues could raise hopes for greater functional recovery,” the institute said. “Cultivated tissues are still insufficient and too small to be used to treat stroke patients. But study of in-vitro cultivation of more mature cortex tissues, such as those with six zones like in the adult human brain, will be stepped up,” it said. The tissues could also serve as “a mini organ” for studying the causes of Alzheimer’s disease, it said.
Embryonic stem cells are harvested by destroying a viable embryo, a process that some find unacceptable. Riken said cortex tissues were also obtained from “induced pluripotent stem cells,” which are similar to embryonic stem cells but artificially induced.
hopes for the treatment of disease.
Stem cells taken from human embryos have been used to form tissues of the cerebral cortex, the supreme control tower of the brain, according to experts at the government-backed research institute Riken. The tissues self-organised into four distinct zones very similar to the structure seen in human foetuses, and conducted neuro-activity such as transmitting electrical signals.
Research on stem cells is seen as having the potential to save lives by helping to find cures for diseases such as cancer and diabetes or to replace damaged cells, tissues and organs. The team’s previous studies showed stem cells differentiated into distinct cells but until now they had never organised into functioning tissues.
“In regenerative therapy, only a limited number of diseases can be cured with simple cell transplants. Transplanting tissues could raise hopes for greater functional recovery,” the institute said. “Cultivated tissues are still insufficient and too small to be used to treat stroke patients. But study of in-vitro cultivation of more mature cortex tissues, such as those with six zones like in the adult human brain, will be stepped up,” it said. The tissues could also serve as “a mini organ” for studying the causes of Alzheimer’s disease, it said.
Embryonic stem cells are harvested by destroying a viable embryo, a process that some find unacceptable. Riken said cortex tissues were also obtained from “induced pluripotent stem cells,” which are similar to embryonic stem cells but artificially induced.
Joblessness can lead to depression
Being unemployed can have long-term and possibly permanent psychological effects, including low self esteem, depression and anxiety, on an Depression (Getty Images)
individual, according to a new study.
The research team led by Arthur H. Goldsmith, the Jackson T. Stephens Professor of Economics at Washington and Lee University said that as the period of unemployment increases the effects often become chronic. “In the first phase of unemployment, people have a benign ignorance and think it will turn out fine, that they are not going to be emotionally damaged by this, because they’ll just go out and get a job,” said Goldsmith.
Approximately half of unemployed people do find a job in about five weeks, but he stresses that, “even by five weeks you can see the changes. They begin to question themselves: ‘Why was I selected to be unemployed?’ ‘Were my skills lacking?’ ‘Is there something about me that’s problematic?’
And so begins the erosion of self esteem, which is such a very important part of our psychological well being. He said that in addition to a diminished sense of self, those exposed to a few months of unemployment begin to exhibit higher levels of anxiety, depression, and lack of sleep.
And if the period of unemployed exceeds six to nine months or longer, the psychological effects often become chronic and have a long lasting effect.
“Looking at longer periods of unemployment, say four to six months, we see statistically significant evidence of people becoming more externally focused and feeling helpless,” he said.
“What’s really interesting is that this compromised sense of self becomes hardens and is better described as a permanent scar rather than a blemish.
“Even when people become employed again, the adverse impact of unemployment on psychological well-being lingers,” he added.
The researchers identified two different types of individuals: Those with an internal locus, who feel that they influence the things that happen to them, and those with an external locus, who believe that they don’t have much control over their lives and that events just happen to them.
An important distinction between people with these differencing mind-sets is that person’s with a more internal locus tend to be more motivated, since they see a tight connection between actions they take and life outcomes. More highly educated people are the most vulnerable to the psychological ravages of unemployment because they tend to be more internally focused.
“So when these people become unemployed they tend to attribute this to personal shortcomings which fosters helplessness and a compromised view of self,” said Goldsmith.
Sexy TV shows drive teen pregnancy
CHICAGO: Exposure to some forms of entertainment is a corrupting influence on children, leading teens who watch sexy programs into early pregnancies
and children who play violent videogames to adopt aggressive behaviour, researchers said on Monday.
Researchers at the RAND research organization said their three-year study was the first to link viewing of racy television programming with risky sexual behaviour by teens.
"Our findings suggest that television may play a significant role in the high rates of teenage pregnancy in the United States," said Anita Chandra, a behavioural scientist who led the research at RAND, a non-profit research organization.
"We're not saying we're establishing causation, but we are saying this is one factor that we were able to prospectively link to the teen pregnancy outcome," Chandra said in a phone interview.
The researchers recruited adolescents aged 12 to 17 and surveyed them three times between 2001 and 2004, asking about television viewing habits, sexual behaviour and pregnancy.
In findings that covered 718 teenagers, there were 91 pregnancies. The top 10th of adolescents who watched the most sexy programming were at double the risk of becoming pregnant or causing a pregnancy compared to the 10th who watched the fewest such programs, according to the study published in the journal Paediatrics.
The study focused on 23 free and cable television programs popular among teenagers including situation comedies, dramas, reality programs and animated shows. Comedies had the most sexual content and reality programs the least.
"The television content we see very rarely highlights the negative aspects of sex or the risks and responsibilities," Chandra said. "So if teens are getting any information about sex they're rarely getting information about pregnancy or sexually transmitted diseases."
Teen pregnancy rates in the United States have declined sharply since 1991 but remain high compared to other industrialized nations. Nearly 1 million girls aged 15 to 19 years old become pregnant yearly, or about 20% of sexually active females in that age group. Most of the pregnancies were unplanned, the report said.
Young mothers are more likely to quit school, require public assistance and live in poverty, it said. "Television is just one part of a teenager's media diet that helps to influence their behaviour. We should also look at the roles that magazines, the Internet and music play in teens' reproductive health," Chandra said, acknowledging still other factors can influence teen sex habits.
and children who play violent videogames to adopt aggressive behaviour, researchers said on Monday.
Researchers at the RAND research organization said their three-year study was the first to link viewing of racy television programming with risky sexual behaviour by teens.
"Our findings suggest that television may play a significant role in the high rates of teenage pregnancy in the United States," said Anita Chandra, a behavioural scientist who led the research at RAND, a non-profit research organization.
"We're not saying we're establishing causation, but we are saying this is one factor that we were able to prospectively link to the teen pregnancy outcome," Chandra said in a phone interview.
The researchers recruited adolescents aged 12 to 17 and surveyed them three times between 2001 and 2004, asking about television viewing habits, sexual behaviour and pregnancy.
In findings that covered 718 teenagers, there were 91 pregnancies. The top 10th of adolescents who watched the most sexy programming were at double the risk of becoming pregnant or causing a pregnancy compared to the 10th who watched the fewest such programs, according to the study published in the journal Paediatrics.
The study focused on 23 free and cable television programs popular among teenagers including situation comedies, dramas, reality programs and animated shows. Comedies had the most sexual content and reality programs the least.
"The television content we see very rarely highlights the negative aspects of sex or the risks and responsibilities," Chandra said. "So if teens are getting any information about sex they're rarely getting information about pregnancy or sexually transmitted diseases."
Teen pregnancy rates in the United States have declined sharply since 1991 but remain high compared to other industrialized nations. Nearly 1 million girls aged 15 to 19 years old become pregnant yearly, or about 20% of sexually active females in that age group. Most of the pregnancies were unplanned, the report said.
Young mothers are more likely to quit school, require public assistance and live in poverty, it said. "Television is just one part of a teenager's media diet that helps to influence their behaviour. We should also look at the roles that magazines, the Internet and music play in teens' reproductive health," Chandra said, acknowledging still other factors can influence teen sex habits.
Foot massage to control errant kids
LONDON: Teachers may now spare the rod without the risk of spoiling schoolchildren, for foot and head messages may help them control bad behaviour
among kids.
A London-based company, Bud-Umbrella, is gearing up to test the alternative therapy in 60 primary and 14 secondary schools to see whether or not it can actually improve unruly children's behaviour.
Though there is little evidence that such a treatment can improve behaviour, Lambeth Council in south London is said to have decided to spend £90,000 next year on reflexology in the schools. Bud-Umbrella's official website says that reflexology may be beneficial in a number of ways.
"It can calm aggressive feelings, improve listening skills, concentration and focus. It can relieve anxiety and stress, and improve confidence and self esteem," the Telegraph quoted the website as saying.
Lambeth Labour councillor Paul McGlone said: "It's incredibly important that we address young people's behavioural problems and we make no apologies for using different and innovative methods but this obviously won't replace more traditional ways of dealing with anti-social behaviour. We need to deal with the root causes of young people's behavioural problems and nip them in the bud - prevention is better than cure." However, everyone is not gaga about the initiative.
among kids.
A London-based company, Bud-Umbrella, is gearing up to test the alternative therapy in 60 primary and 14 secondary schools to see whether or not it can actually improve unruly children's behaviour.
Though there is little evidence that such a treatment can improve behaviour, Lambeth Council in south London is said to have decided to spend £90,000 next year on reflexology in the schools. Bud-Umbrella's official website says that reflexology may be beneficial in a number of ways.
"It can calm aggressive feelings, improve listening skills, concentration and focus. It can relieve anxiety and stress, and improve confidence and self esteem," the Telegraph quoted the website as saying.
Lambeth Labour councillor Paul McGlone said: "It's incredibly important that we address young people's behavioural problems and we make no apologies for using different and innovative methods but this obviously won't replace more traditional ways of dealing with anti-social behaviour. We need to deal with the root causes of young people's behavioural problems and nip them in the bud - prevention is better than cure." However, everyone is not gaga about the initiative.
'Water monster' on brink of extinction
MEXICO CITY: Beneath the tourist gondolas in the remains of a great Aztec lake lives a creature that resembles a monster — and a Muppet — with its
slimy tail, plumage-like gills and mouth that curls into an odd smile.
The axolotl, also known as the "water monster" and the "Mexican walking fish," was a key part of Aztec legend and diet. Against all odds, it survived until now amid Mexico City's urban sprawl in the polluted canals of Lake Xochimilco, now a Venice-style destination for revellers poled along by Mexican gondoliers, or trajineros, in brightly painted party boats.
But scientists are racing to save the foot-long salamander from extinction, a victim of the draining of its lake habitat and deteriorating water quality. In what may be the final blow, nonnative fish introduced into the canals are eating its lunch — and its babies.
The long-standing International Union for Conservation of Nature includes the axolotl on its annual Red List of threatened species, while researchers say it could disappear in just five years. Some are pushing for a series of axolotl sanctuaries in canals cleared of invasive species, while others are considering repopulating Xochimilco with axolotls bred in captivity.
"If the axolotl disappears, it would not only be a great loss to biodiversity but to Mexican culture, and would reflect the degeneration of a once-great lake system," says Luis Zambrano, a biologist.
slimy tail, plumage-like gills and mouth that curls into an odd smile.
The axolotl, also known as the "water monster" and the "Mexican walking fish," was a key part of Aztec legend and diet. Against all odds, it survived until now amid Mexico City's urban sprawl in the polluted canals of Lake Xochimilco, now a Venice-style destination for revellers poled along by Mexican gondoliers, or trajineros, in brightly painted party boats.
But scientists are racing to save the foot-long salamander from extinction, a victim of the draining of its lake habitat and deteriorating water quality. In what may be the final blow, nonnative fish introduced into the canals are eating its lunch — and its babies.
The long-standing International Union for Conservation of Nature includes the axolotl on its annual Red List of threatened species, while researchers say it could disappear in just five years. Some are pushing for a series of axolotl sanctuaries in canals cleared of invasive species, while others are considering repopulating Xochimilco with axolotls bred in captivity.
"If the axolotl disappears, it would not only be a great loss to biodiversity but to Mexican culture, and would reflect the degeneration of a once-great lake system," says Luis Zambrano, a biologist.
Brain slows at 40, starts body decline
WASHINGTON: The brain may explain why people slow down as they get older, starting at age 40.
How fast you can throw a ball or run or swerve a steering wheel depends on how speedily brain cells fire off commands to muscles. Fast firing depends on good insulation for your brain's wiring.
Now new US research suggests that in middle age, even healthy people begin to lose some of that insulation in a motor-control part of the brain - at the same rate that their speed subtly slows.
That helps explain why "it's hard to be a world-class athlete after 40," concludes George Bartzokis, a neurologist at University of California, Los Angeles, who led the work.
And while that may sound depressing, keep reading. The research points to yet another reason to stay physically and mentally active: An exercised brain may spot fraying insulation quicker and signal for repair cells to get to work.
To Bartzokis, the brain is like the Internet. Speedy movement depends on bandwidth, which in the brain is myelin, a special sheet of fat that coats nerve fibres.
Healthy myelin - good thick insulation wound tightly around those nerve fibres - allows prompt conduction of the electrical signals the brain uses to send commands. Higher-frequency electrical discharges, known as "actional potentials," speed movement - any movement, from a basketball rebound to a finger tap.
Consider someone like Michael Jordan. "The circuitry that made him a great basketball player was probably myelinated better than most other mortals," Bartzokis notes.
But while myelin builds up during adolescence, when does production slow enough that we fall behind in the race to repair fraying, older insulation?
How fast you can throw a ball or run or swerve a steering wheel depends on how speedily brain cells fire off commands to muscles. Fast firing depends on good insulation for your brain's wiring.
Now new US research suggests that in middle age, even healthy people begin to lose some of that insulation in a motor-control part of the brain - at the same rate that their speed subtly slows.
That helps explain why "it's hard to be a world-class athlete after 40," concludes George Bartzokis, a neurologist at University of California, Los Angeles, who led the work.
And while that may sound depressing, keep reading. The research points to yet another reason to stay physically and mentally active: An exercised brain may spot fraying insulation quicker and signal for repair cells to get to work.
To Bartzokis, the brain is like the Internet. Speedy movement depends on bandwidth, which in the brain is myelin, a special sheet of fat that coats nerve fibres.
Healthy myelin - good thick insulation wound tightly around those nerve fibres - allows prompt conduction of the electrical signals the brain uses to send commands. Higher-frequency electrical discharges, known as "actional potentials," speed movement - any movement, from a basketball rebound to a finger tap.
Consider someone like Michael Jordan. "The circuitry that made him a great basketball player was probably myelinated better than most other mortals," Bartzokis notes.
But while myelin builds up during adolescence, when does production slow enough that we fall behind in the race to repair fraying, older insulation?
Stretching before exercise can be bad
LONDON: Stretching before exercise can be bad for individuals, warn scientists, who found that the integral part of any athlete's warm-up routine
can actually weaken muscles.
It has long been believed that the habit of holding a stretch for 20 to 30 seconds, known as static stretching, is beneficial for priming muscles.
But now, in a new research, scientists from the University of Nevada Las Vegas say this should no longer be encouraged.
Their findings highlight that the two common pre-running stretches - for the hamstrings and quadriceps - may actually reduce performance by weakening muscles in the leg.
"Developing flexibility is important for reducing sports injury, but the time to stretch is after, not before, performance," the Telegraph quoted Kinesiology professor Bill Holcomb, who authored the report, as saying.
Other studies have found that this stretching decreases muscle strength by as much as 30 per cent. Stretching one leg's muscles can also reduce strength in the other leg as the central nervous system can rebel against the movements.
The correct warm up, according to experts, should do two things - loosen muscles and tendons to increase the range of motion of various joints, and warm up the body.
To raise the body's temperature, a warm-up should begin with aerobic activity, and researchers recommend light jogging.
can actually weaken muscles.
It has long been believed that the habit of holding a stretch for 20 to 30 seconds, known as static stretching, is beneficial for priming muscles.
But now, in a new research, scientists from the University of Nevada Las Vegas say this should no longer be encouraged.
Their findings highlight that the two common pre-running stretches - for the hamstrings and quadriceps - may actually reduce performance by weakening muscles in the leg.
"Developing flexibility is important for reducing sports injury, but the time to stretch is after, not before, performance," the Telegraph quoted Kinesiology professor Bill Holcomb, who authored the report, as saying.
Other studies have found that this stretching decreases muscle strength by as much as 30 per cent. Stretching one leg's muscles can also reduce strength in the other leg as the central nervous system can rebel against the movements.
The correct warm up, according to experts, should do two things - loosen muscles and tendons to increase the range of motion of various joints, and warm up the body.
To raise the body's temperature, a warm-up should begin with aerobic activity, and researchers recommend light jogging.
Sexy TV shows drive teen pregnancy
CHICAGO: Exposure to some forms of entertainment is a corrupting influence on children, leading teens who watch sexy programs into early pregnancies
and children who play violent videogames to adopt aggressive behaviour, researchers said on Monday.
Researchers at the RAND research organization said their three-year study was the first to link viewing of racy television programming with risky sexual behaviour by teens.
"Our findings suggest that television may play a significant role in the high rates of teenage pregnancy in the United States," said Anita Chandra, a behavioural scientist who led the research at RAND, a non-profit research organization.
"We're not saying we're establishing causation, but we are saying this is one factor that we were able to prospectively link to the teen pregnancy outcome," Chandra said in a phone interview.
The researchers recruited adolescents aged 12 to 17 and surveyed them three times between 2001 and 2004, asking about television viewing habits, sexual behaviour and pregnancy.
In findings that covered 718 teenagers, there were 91 pregnancies. The top 10th of adolescents who watched the most sexy programming were at double the risk of becoming pregnant or causing a pregnancy compared to the 10th who watched the fewest such programs, according to the study published in the journal Paediatrics.
The study focused on 23 free and cable television programs popular among teenagers including situation comedies, dramas, reality programs and animated shows. Comedies had the most sexual content and reality programs the least.
"The television content we see very rarely highlights the negative aspects of sex or the risks and responsibilities," Chandra said. "So if teens are getting any information about sex they're rarely getting information about pregnancy or sexually transmitted diseases."
Teen pregnancy rates in the United States have declined sharply since 1991 but remain high compared to other industrialized nations. Nearly 1 million girls aged 15 to 19 years old become pregnant yearly, or about 20% of sexually active females in that age group. Most of the pregnancies were unplanned, the report said.
Young mothers are more likely to quit school, require public assistance and live in poverty, it said. "Television is just one part of a teenager's media diet that helps to influence their behaviour. We should also look at the roles that magazines, the Internet and music play in teens' reproductive health," Chandra said, acknowledging still other factors can influence teen sex habits.
and children who play violent videogames to adopt aggressive behaviour, researchers said on Monday.
Researchers at the RAND research organization said their three-year study was the first to link viewing of racy television programming with risky sexual behaviour by teens.
"Our findings suggest that television may play a significant role in the high rates of teenage pregnancy in the United States," said Anita Chandra, a behavioural scientist who led the research at RAND, a non-profit research organization.
"We're not saying we're establishing causation, but we are saying this is one factor that we were able to prospectively link to the teen pregnancy outcome," Chandra said in a phone interview.
The researchers recruited adolescents aged 12 to 17 and surveyed them three times between 2001 and 2004, asking about television viewing habits, sexual behaviour and pregnancy.
In findings that covered 718 teenagers, there were 91 pregnancies. The top 10th of adolescents who watched the most sexy programming were at double the risk of becoming pregnant or causing a pregnancy compared to the 10th who watched the fewest such programs, according to the study published in the journal Paediatrics.
The study focused on 23 free and cable television programs popular among teenagers including situation comedies, dramas, reality programs and animated shows. Comedies had the most sexual content and reality programs the least.
"The television content we see very rarely highlights the negative aspects of sex or the risks and responsibilities," Chandra said. "So if teens are getting any information about sex they're rarely getting information about pregnancy or sexually transmitted diseases."
Teen pregnancy rates in the United States have declined sharply since 1991 but remain high compared to other industrialized nations. Nearly 1 million girls aged 15 to 19 years old become pregnant yearly, or about 20% of sexually active females in that age group. Most of the pregnancies were unplanned, the report said.
Young mothers are more likely to quit school, require public assistance and live in poverty, it said. "Television is just one part of a teenager's media diet that helps to influence their behaviour. We should also look at the roles that magazines, the Internet and music play in teens' reproductive health," Chandra said, acknowledging still other factors can influence teen sex habits.
Heavy women have more sex
Those who think women scoring more on the weighing scale do not score much when it comes to sexual behaviour, certainly need a reality check, for a Fat ladies have more sex
new study has revealed that fat ladies have more sex than females with "normal weight”.
Oregon and Hawaiian researchers have found that a woman''s weight does not seem to affect sexual behaviour.
Led by Dr. Bliss Kaneshiro, an assistant professor at the School of Medicine at the University of Hawaii, and Oregon State University professor Marie Harvey, the study was based on data from the 2002 National Survey of Family Growth that looked at sexual behaviour of more than 7,000 women.
In earlier studies it was Kaneshiro observed that obese and overweight women have a higher risk of unintended pregnancy than do normal weight women.
Thus, Kaneshiro studied the relationship between body mass index and sexual behavior, including sexual orientation, age at first intercourse, number of partners, and frequency of intercourse.
"Our analysis demonstrated that obese and overweight women do not differ significantly in some of the objective measures of sexual behavior compared to women of normal weight. This study indicates that all women deserve diligence in counseling on unintended pregnancy and STD prevention, regardless of body mass index," said Kaneshiro.
The study ruled out the widely held stereotypes that overweight and obese women are not as sexually active as other women, as the researchers concluded that it’s the opposite that is true.
"I was glad to see that the stereotype that you have to be slender to have sex is just that, a stereotype," said Harvey.
The data revealed that overweight women were more likely to report having sexual intercourse with a man, even when she controlled for age, race and type of residence.
In fact, 92 percent of overweight women reported having a history of sexual intercourse with a man, as compared to 87 percent of women with a normal body mass index.
"These results were unexpected and we don't really know why this is the case," said Kaneshiro.
Kaneshiro's study was awarded first prize at the American College of Obstetricians and Gynecologists'' annual meeting this year.
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