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2012 Feb 8

چهارشنبه 19 بهمن 1390

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2012-2-2

Sugar tax needed, say US experts
According to a University of California team, new policies such as taxes are needed to control soaring consumption of sugar and sweeteners.Prof Robert Lustig argues in the journal Nature for major shifts in public policy.Industry body the Food and Drink Federation said "demonising" food was unhelpful.Several countries are imposing taxes on unhealthy food; Denmark and Hungary have a tax on saturated fat, while France has approved a tax on soft drinks. Now, researchers in the US are proposing similar policies for added sugar and sweeteners, amid concern about the amount of sugar in the diet. The consumption of sugar has tripled worldwide over the past 50 years, with links to obesity, high blood pressure and diabetes.In a comment in the journal Nature, Prof Lustig, a leading child obesity expert, says governments need to consider major shifts in policy, such as taxes, limiting sales of sweet food and drinks during school hours, or even stopping children from buying them below a certain age.The professor of paediatrics at the University of California, San Francisco, told the BBC: "It [sugar] meets all the criteria for societal intervention that alcohol and tobacco meet."The researchers acknowledge that they face "an uphill political battle against a powerful sugar lobby".But they write in Nature, that "with enough clamour for change, tectonic shifts in policy become possible"."Take, for instance bans on smoking in public places and the use of designated drivers, not to mention airbags in cars and condom dispensers in public bathrooms."These simple measures - which have all been on the battleground of American politics - are now taken for granted as essential tools for our public health and well-being. It's time to turn our attention to sugar."

2012-1-12

Web addicts have brain changes, research suggests
Experts in China scanned the brains of 17 young web addicts and found disruption in the way their brains were wired up.They say the discovery, published in Plos One, could lead to new treatments for addictive behaviour. Internet addiction is a clinical disorder marked by out-of-control internet use.A research team led by Hao Lei of the Chinese Academy of Sciences in Wuhan carried out brain scans of 35 men and women aged between 14 and 21.Seventeen of them were classed as having internet addiction disorder (IAD) on the basis of answering yes to questions such as, "Have you repeatedly made unsuccessful efforts to control, cut back or stop Internet use?"Specialised MRI brain scans showed changes in the white matter of the brain - the part that contains nerve fibres - in those classed as being web addicts, compared with non-addicts.There was evidence of disruption to connections in nerve fibres linking brain areas involved in emotions, decision making, and self-control.Dr Hao Lei and colleagues write in Plos One: "Overall, our findings indicate that IAD has abnormal white matter integrity in brain regions involving emotional generation and processing, executive attention, decision making and cognitive control."The results also suggest that IAD may share psychological and neural mechanisms with other types of substance addiction and impulse control disorders."Prof Gunter Schumann, chair in biological psychiatry at the Institute of Psychiatry at King's College, London, said similar findings have been found in video game addicts.He told the BBC: "For the first time two studies show changes in the neuronal connections between brain areas as well as changes in brain function in people who are frequently using the internet or video games."Commenting on the Chinese study, Dr Henrietta Bowden-Jones, consultant psychiatrist and honorary senior lecturer at Imperial College London, said the research was "groundbreaking".She added: "We are finally being told what clinicians suspected for some time now, that white matter abnormalities in the orbito-frontal cortex and other truly significant brain areas are present not only in addictions where substances are involved but also in behavioural ones such as internet addiction."She said further studies with larger numbers of subjects were needed to confirm the findings.

2011-12-29

Venezuela offers free removal of faulty breast implants
The authorities would cover the cost of the surgery for Venezuelan women but would not pay for replacement implants, Health Minister Eugenia Sader said. Ms Sader said many implants made by French firm Poly Implant Prothese (PIP) had been imported illegally. The French authorities have recommended that 30,000 French women have the PIP implants removed as a precaution.The French government, which stresses that there is no evidence of a cancer link, has said it will cover the cost. The implants were banned in several countries last year after they were found to contain industrial grade silicone filler, making them more liable to split. The French authorities have opened a criminal investigation into the company which went into administration in 2010. Ms Sader said that patients who were worried could go to hospital for a check-up and have surgery to remove the implants if they wished. The Venezuelan government would not, however, pay for new implants, the state news agency AVN quoted her as saying. The health minister said that a significant number of PIP implants had been brought into Venezuela without the proper authorisation."They were implanted illegally and now those patients are at risk," she said. Breast augmentation surgery is popular in Venezuela, where implants are sometimes given to girls as a 15th birthday present.More than 300,000 implants are believed to have been sold globally by PIP over the past 12 years in some 65 countries. More than half of its exports went to South America. In Brazil, some 25,000 women are believed to have had PIP implants. In Argentina, a group of some 50 women have said they will sue their plastic surgeons if they do not get free replacement for their PIP implants. Western Europe was another major market. Spain, Italy, Germany and Ukraine are known to have imported PIP silicon sacs.It is thought some 40,000 British women have the implants.

2011-12-7

Bisphosphonates 'extend hip replacement life'
Researchers analysed data from patients who were taking bisphosphonates, which are used to prevent the loss of bone material.However, scientists say further studies are still needed.When joints become damaged or worn out, commonly due to osteoarthritis, it can be painful and limits movement.An implant can dramatically improve a patient's mobility. More than 50,000 hip and 70,000 knee, replacements take place in the UK each year.While they can last for decades, some fail within years. This can happen when the bone around the implant is dissolved by the body meaning the replacement joint becomes loose.The theory was that bisphosphonates, which are used by patients with osteoporosis to prevent bone being broken down, would prevent the loosening.The researchers looked at data from General Practice Research Database for joint replacements and compared what happened to 1,912 patients taking bisphosphonates with 41,995 patients who did not.After five years, 1.96% of implants failed without the drug, compared with 0.93% in those taking medication.Prof Nigel Arden, a specialist in rheumatic diseases at the Universities of Oxford and Southampton, said the first implant would cost the NHS about £7,000, but replacements would cost £34,000.He told the BBC: "It has the potential to have a huge impact." He said two of the risk factors, age and obesity, meant the number of cases was "increasing dramatically".Prof Arden is not arguing that people should be given the drug yet. He has applied for funding for a further trial to test the effectiveness of bisphosphonates and which patients would benefit most.The chief medical officer for England, Prof Dame Sally Davies welcomed the findings."With such a high incidence of knee and hip replacement surgery, the possibility that the life of joint implants could be lengthened and reduce the number of complex revision surgeries means that these results have the potential to make significant improvements to the lives of many NHS patients," she said.

2011-12-6

Vaccine developed against Ebola
Scientists have developed a vaccine that protects mice against a deadly form of the Ebola virus. First identified in 1976, Ebola fever kills more than 90% of the people it infects.The researchers say that this is the first Ebola vaccine to remain viable long-term and can therefore be successfully stockpiled.The results are reported in the journal Proceedings of National Academy of Sciences. Ebola is transmitted via bodily fluids, and can become airborn. Sufferers experience nausea, vomiting, internal bleeding and organ failure before they die.Although few people contract Ebola each year, its effects are so swift and devastating that it is often feared that it could be used against humans in an act of terroism. All previously developed vaccines have relied on injecting intact, but crippled, viral particles into the body.Long-term storage tends to damage the virus, paralysing the vaccine's effectiveness. The new vaccine contains a synthetic viral protein, which prompts the immune system to better recognise the Ebola virus, and is much more stable when stored long-term. The vaccine protects 80% of the mice injected with the deadly strain, and survives being "dried down and frozen," said biotechnologist Charles Arntzen from Arizona State University who was involved in its development. He said the next step is to try the vaccine on a strain of Ebola that is closer to the one that infects humans.

2011-9-26

Alpha radiation treats prostate cancers
Doctors at London's Royal Marsden Hospital gave prostate cancer patients a powerful alpha radiation drug and found that they lived longer, and experienced less pain and side effects.The medics then stopped the trial of 922 people, saying it was unethical not to offer all of them the treatment.Lead researcher Dr Chris Parker said it was "a significant step forward".Cancer Research UK said it was a very important and promising discovery.Radiation has been used to treat tumours for more than a century. It damages the genetic code inside cancerous cells. Alpha particles are the big, bulky, bruisers of the radiation world. It is a barrage of helium nuclei, which are far bigger than beta radiation, a stream of electrons, or gamma waves.Dr Parker told the BBC: "It's more damaging. It takes one, two, three hits to kill a cancer cell compared with thousands of hits for beta particles."Alpha particles also do less damage to surrounding tissue. He added: "They have such a tiny range, a few millionths of a metre. So we can be sure that the damage is being done where it should be."In 90% of patients with advanced prostate cancer, the tumour will have spread to the bone. At this stage there are no treatments which affect survival.The study looked at patients with these secondary cancers, as the source of radiation - radium-223 chloride - acts like calcium and sticks to bone.Half were given the radium-223 chloride drug alongside traditional chemotherapy, while the other patients received chemotherapy and a dummy pill.The death rate was 30% lower in the group taking radium-223. Those patients survived for 14 months on average compared to 11 months in the dummy group.The trial was abandoned as "it would have been unethical not to offer the active treatment to those taking placebo",said Dr Parker.

2011-5-5

Juice cocktail 'good for heart'
A blend of fruit juices, including grape, cranberry and blackcurrant, may have benefits for the heart, research suggests.French scientists tested the blend on pig arteries in the lab, and found it caused artery walls to relax.It remains to be seen whether fruit juices can improve vascular health, they report in a scientific journal.The study adds weight to evidence fruit and veg reduces heart disease risk, says the British Heart Foundation.The researchers looked for a chemical called polyphenol in fruit and berries.They found the most active fruits included blackcurrant, blueberry, aronia (choke berries), cranberry, lingonberry and grape.Commenting on the study, Tracy Parker, heart health dietitian at the British Heart Foundation, said: "This research adds more weight to evidence that eating fruit and vegetables is good for us in terms of reducing our risk for heart disease."However, we still don't fully understand why, or whether certain fruits and vegetables are better than others. Even this study acknowledges that scientists can't yet explain any link."What we do know is that we should all eat a wide range of fruit and veg as part of a balanced diet, and fruit juice is a tasty and handy way of doing this. "Don't forget though, juice contains less fibre and more sugar than the original fruit so it only counts as one of our five-a-day."The research was published in the Royal Society of Chemistry journal, Food and Function.

2011-4-25

Cases of malaria among UK travellers rise by 30%
New figures from the Health Protection Agency (HPA) reveal there were 1,761 new cases in 2010.Over the past decade most infections have occurred among people who visited West Africa or South Asia.The HPA is warning travellers to heed advice on how to avoid malaria, which is the world's second biggest killer.In 2008 there were 1,370 new cases but the following year the numbers increased to 1,495.In 2010, almost 40% of UK residents who contracted the disease had visited either Nigeria or Ghana, while 11% had been to India.
The HPA believes these travellers may not have sought or were unable to access advice on malaria prevention or had not thought they were at risk because they knew the area they were travelling to.And these kind of travellers appear to be more at risk because they generally stay for longer than other visitors, such as those on business.They also tend to stay with friends and family rather than in hotels or resorts, and so are exposed to the same risk of contracting the disease as local people.Professor Peter Chiodini, who heads the HPA's malaria reference laboratory, said the figures - released on World Malaria Day - are a timely reminder for travellers to take precautions against the disease. "Anyone who is travelling to a country where malaria is present should take travel advice and appropriate medication."Even people living in Britain visiting the country in which they were born or grew up, or have previously visited, are not immune from malaria and should take precautions."

2011-4-11

Drinking over recommended limit 'raises cancer risk'
Drinking more than a pint of beer a day can substantially increase the risk of some cancers, research suggests.The Europe-wide study of 363,988 people reported in the British Medical Journal found one in 10 of all cancers in men and one in 33 in women were caused by past or current alcohol intake.More than 18% of alcohol-related cancers in men and about 4% in women were linked to excessive drinking.The Department of Health said it was taking action to reduce drinking.Cancer charities say people should limit their drinking to lower the risk.The study calculated that in 2008 current and past drinking habits were responsible for about 13,000 cancer cases in the UK, out of a total of 304,000 cases.Previous research has shown a link between alcohol consumption and cancers of the oesophagus, liver, bowel and female breast.When alcohol is broken down by the body it produces a chemical which can damage DNA, increasing the chance of developing cancer.

2011-3-25

Tick warning issued by Scotland mountaineering group
Warm weather appears to have encouraged parasitic ticks to emerge earlier than last year, the Mountaineering Council of Scotland (MCofS) has said.MCofS membership development officer Mike Dales said he found his first tick of the year on Saturday.He recorded his first of 2010 on 29 April.Lyme disease, an infection that can cause arthritis if untreated, can be transmitted to humans through a tick bite.Mr Dales said the parasite was on his right leg.He may have picked it up in the garden of his Perthshire home, or during a trip to the Highlands to compete in the Newtonmore 10-mile road race, and also for a walk up Meall na h-Aisre.In a warning to other walkers, he said: "So much for the theory that says the hard winter will have hit Scotland's tick population. "Yesterday was mild though. "Despite the breeze making it feel a bit cooler, our weather station recorded a high of 12.9C yesterday afternoon."He added: "That warm temperature was no doubt responsible for bringing the tick that attached itself to my leg out of the undergrowth."

2011-3-23

Sexual preference chemical found in mice
A chemical in the brain controls sexual preference in mice, according to scientists in China.Male mice bred without serotonin lose their preference for females, a report in Nature says.The researchers say it is the first time that a neurotransmitter has been shown to play a role in sexual preference in mammals.Experts have warned about the dangers of drawing conclusions about human sexuality.The research team first bred male mice whose brains were not receptive to serotonin.A series of experiments demonstrated that these mice had lost the preference for females shown by unmodified males.When presented with a choice of partners, they showed no overall preference for either males or females. When just a male was introduced into the cage, the modified males were far more likely to mount the male and emit a "mating call" normally given off when encountering females than unmodified males were.Similar results were achieved when a different set of mice were bred. These lacked the tryptonphan hydroxylase 2 gene, which is needed to produce serotonin.However, a preference for females could be "restored" by injecting serotonin into the brain.The report concludes: "Serotonergic signalling is crucial for male sexual preference in mice. This is the first time, to our knowledge, that a neurotransmitter in the brain has been demonstrated to be important in mammalian sexual preference."

2011-3-10

Call to vaccinate against possible H2N2 flu pandemic
The US authors say immunity to the H2N2 flu strain is very low in people under the age of 50.But a safe vaccine already exists after an H2N2 outbreak in the 1950s and '60s.They say that vaccinating now could save billions of dollars if a pandemic does develop.Dr Gary Nabel and colleagues from the Vaccine Research Centre in the US say H2N2 has the ability to cause a pandemic in the same way that H1N1 did in 2009.Between 1957 and 1968, the strain is thought to have caused up to 4 million deaths in a global outbreak, during which time a vaccine was developed.When the pandemic was over the H2N2 vaccination programme was stopped in the late 1960s, although the virus is still present today among birds and swine.That means older people will have been vaccinated against the virus, but the relatively young will have missed out - what the authors call the vulnerability of youth.Between 2003 and 2007 they examined levels of immunity to H2N2 among a small group of 90 people."Our study suggests that people under the age of 50 have little or no immunity, and resistance dramatically increases for those older than 50. This was also the case for the 2009 H1N1."They argue that the vaccine developed in the 1950s would still work today and that governments should use this to develop a pre-emptive vaccination programme."One approach would be to manufacture the vaccine licensed in 1957 and immunise enough of the world's population to provide 'herd immunity' to the rest. "This could be achieved by a 'one-time' campaign to immunise most of the adult population worldwide - for example, as part of standard seasonal flu vaccinations - accompanied by an ongoing programme to administer the vaccine to children."

2011-2-22

Cholesterol 'does not predict stroke in women'
The report in Annals of Neurology recommends using a different type of fat in the blood, non-fasting triglycerides, to measure the risk.The Stroke Association said triglyceride tests needed to become routine to reduce the risk of stroke.A total of 150,000 people have a stroke in the UK each year. Most are ischemic strokes, in which a clot in an artery disrupts the brain's blood supply.The research followed 13,951 men and women, who took part in the Copenhagen City Heart Study.During the 33-year study, 837 men and 837 women had strokes.They reported that the cholesterol levels in women were not associated with stroke, while there was only an association in men with levels higher than 9mmol/litre. The average in UK men is 5.5.The researchers at Copenhagen University Hospital said this was "difficult to explain" as LDL, or bad, cholesterol is known to cause atherosclerosis which can block arteries.They did notice a link, in both men and women, between the risk of stroke and non-fasting triglycerides.They believe these fats are a marker for "remnant cholesterol" which is left behind when other forms of cholesterol are made. Dr Peter Coleman, deputy director of research at The Stroke Association said: "Tests for triglyceride levels aren't routinely carried out in the UK unless there is significant concern." "We know that high levels of fats, such as cholesterol, increase your risk of having a stroke. However, this research shows the importance of measuring the fat triglyceride, as well as cholesterol."This study highlights the importance of measuring triglycerides routinely in order to reduce a person's risk of stroke."

2011-2-7

Peanut allergy diagnoses 'higher in boys'
The study in the Journal of Allergy and Clinical Immunology by Edinburgh University researchers analysed 2005 data from over 400 English GP practices. Children from higher income homes also appeared more likely to be diagnosed.However, a leading allergy expert said that "inequality of access" to health care could be the reason. The researchers looked at data on peanut allergies actually diagnosed by a doctor, rather than the actual incidence amongst a population.The records of a total of nearly three million patients were examined.Babies and younger boys were up to 30% more likely to be diagnosed with a peanut allergy than girls of the same age, a figure that confirms previous research into peanut allergies.However, the gap in diagnoses between the sexes narrowed as the children grew up.By the age of 15, girls and boys were being diagnosed at almost the same rates and by the age of 24 the figures were reversed, with more women being diagnosed than men.A researcher from the university, Colin Simpson, said that other allergies had shown higher rates in boys than girls too.The reason for the difference was, he said, still not clear: "There could be a link to the sex hormones, but we don't know for sure. The fact that at puberty there is a change could point to a link, but we need to do more work."

2011-1-31

Frisky bacteria war on drugs revealed
Ever since medicine declared war on bacteria with the discovery of penicillin, the two have been locked in an arms race.Antibiotics are met by resistance from germs; so researchers develop new drugs and germs become resistant again.Now some scientists believe genetics will be the new weapon in the fight, with doctors consulting bacterial genomes when treating disease.This week a team at the Wellcome Trust Sanger Institute published a paper in the journal Science, which they say shows the first genetic picture of the evolutionary war between medicine and bacteria.End Quote Bacterial genetics can be tricky. With humans, one person's DNA is passed on to their children, then to their children, and so on down the family tree. Bacteria are altogether more frisky. They pass DNA onto their descendants when they divide in two, but they also swap DNA with other bacteria, changing their genetic code. It is like popping to the shop and changing eye colour with someone at the checkout.This study has managed to tease out the differences between the two ways of passing on DNA in Streptococcus pneumoniae and draw its family tree.

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