Medicine Hut - Know Your Disease

Study in mice shows why antidepressants often fail

noreply@blogger.com (Medicine Hut) — Fri, 15 Jan 2010 14:37:00 +0000

CHICAGO (Reuters) - Antidepressants fail to help about half of the people who take them, and a study in mice may help explain why.

Most antidepressants -- including the commonly used Prozac and Zoloft -- work by increasing the amount of serotonin, a message-carrying brain chemical made deep in the middle of the brain by cells known as raphe neurons.

Researchers at Columbia University Medical Center in New York said on Wednesday that genetically engineered mice that had too much of one type of serotonin receptor in this region of the brain were less likely to respond to antidepressants.

"These receptors dampen the activity of these (serotonin-producing) neurons. Too much of them dampen these neurons too much," Rene Hen of Columbia, whose study appears in the journal Neuron, said in a telephone interview.

"It puts too much brake on the system."

Hen said the finding may be useful in giving doctors an idea of whether a patient will respond to an antidepressant.

And it could also help drugmakers populate better clinical trials to help identify new drug compounds that work for people who are unlikely to benefit from conventional antidepressants.

"The goal is to figure out something that is useful for the non-responders," he said.

For the study, Hen and colleagues needed to reach serotonin receptors in just the right part of the brain.

To do this, the team used mice that were genetically altered to have fewer serotonin receptors only in the region where the serotonin-producing raphe neurons are located.

Once the team had mice that had different levels of serotonin receptors in different parts of the brain, they did a behavior test that assesses boldness when mice get food in a brightly lit area.

Mice on antidepressants usually become more daring, but the drugs had no such effect on mice with surplus serotonin receptors.

"The most dramatic finding is that the mice that have high levels of receptors in these serotonin neurons do not respond to fluoxetine or Prozac," Hen said.

But when they reduced the number of these receptors -- or molecular doorways -- they were able to reverse the effect, he said.

"By simply tweaking the number of receptors down, we were able to transform a non-responder into a responder," Hen said.

At least 27 million take antidepressants in the United States, nearly double the number that did in the mid-1990s.

Eli Lilly and Co's Prozac, known generically as fluoxetine, and Pfizer Inc's Zoloft or sertraline belong to a class of antidepressants known as selective serotonin reuptake inhibitors, or SSRIs. Other common antidepressants include Forest Laboratories Inc's Celexa, or citalopram, and Lexapro, or escitalopram; and GlaxoSmithKline's Paxil or paroxetine.

Simple test could cut cancer deaths in poor nations

noreply@blogger.com (Medicine Hut) — Fri, 15 Jan 2010 14:37:00 +0000

LONDON (Reuters) - A simple "see and treat" approach using a test costing $2 could help doctors prevent 100,000 cervical cancer deaths a year in women in poorer countries, British scientists said on Friday.

Cervical cancer is the leading cause of cancer death among women in developing nations where the main barriers to tackling the disease are poor health service infrastructure and high costs of screening and vaccines.

But British researchers said visual inspection with acetic acid (VIA) -- which costs significantly less than $9 human papillomavirus (HPV) or cervical cell lab tests more commonly used in developed nations -- could be the answer.

Around 300,000 women worldwide die from cervical cancer each year and up to 85 percent of those deaths occur in developing countries.

"VIA is an effective and affordable tool to screen women for pre-cancerous lesions of the cervix in under-resourced countries," said David McGregor of University College London, who led the research.

"Coupled with simple treatment measures, VIA could potentially reduce these cancer deaths by a third, which means nearly 100,000 women saved each year."

VIA is a simple test where a very small dose of acetate acid solution is applied to the cervix to detect pre-cancerous lesions. A positive result can be treated immediately.

This is referred to as the "see and treat" approach and experts say it can work well in small clinics without advanced equipment and laboratories.

Drug firms Merck & Co and GlaxoSmithKline make Gardasil and Cervarix vaccines which protect against a number of strains of HPV -- the most common sexually transmitted disease in the world and the main cause of cervical cancer.

But unlike in developed nations, where cervical screening programs are well established and vaccination programs against HPV are growing, access to tests and vaccines in many countries in Africa, Asia and southern America is limited.

The study in the Obstetrician & Gynecologist journal said research in rural and isolated communities had shown that VIA is accurate, acceptable to women, and cuts cancer death rates.

But it said raising awareness about screening programs to ensure higher uptake in the population was also a challenge.

Diabetes ups risk of dementia for mildly impaired

noreply@blogger.com (Medicine Hut) — Fri, 15 Jan 2010 14:36:00 +0000

NEW YORK (Reuters Health) - Diabetes may hasten progression to dementia in older people with mild thinking impairment, new research shows.

So-called mild cognitive impairment, or MCI, increases a person's risk of developing Alzheimer's disease and other types of dementia. But aside from a person's severity of mental impairment, there is currently no way to predict which people with MCI will go on to develop full-blown dementia.

Diabetes has been tied to mental decline and dementia in aging, but it is not currently known whether people with MCI who have diabetes are at greater risk of future dementia.

To investigate, Dr. Latha Velayudhan of the Institute of Psychiatry in London and her colleagues followed 103 men and women with MCI over age 65 for four years, during which time 19 developed dementia. Most of these individuals had "probable or possible" Alzheimer's.

The 16 individuals in the study with diabetes were nearly three times as likely to develop dementia as the study participants without diabetes, the researchers report in the British Journal of Psychiatry.

While the study is small, Velayudhan and her colleagues note, it is fairly representative of the population at large because participants were recruited from primary care centers, not specialized memory clinics.

There are several ways that diabetes could speed mental decline, the researchers say, for example through its effects on insulin, which plays a key role in how the brain uses glucose for fuel.

"Whatever the mechanism, with an expected increase in the prevalence of diabetes in people of all ages including older adults, the risk of developing dementia may increase," Velayudhan and her colleagues say.

"Identification of those at particular risk of progression might help to target early treatment -- both pharmacological and social," they conclude.

Suits allege harm from Pfizer quit-smoking drug

noreply@blogger.com (Medicine Hut) — Fri, 15 Jan 2010 14:36:00 +0000

NEW YORK (Reuters) - Three personal injury lawsuits were filed against Pfizer Inc on Thursday, claiming its smoking-cessation drug Chantix caused attempted suicides or death.

The suits, all filed in New York State Supreme Court in Manhattan by the same plaintiffs' law firm, claim Pfizer failed to notify doctors and patients about dangers the company allegedly knew about the pill -- including depression and suicidal thoughts--at the time the plaintiffs took the medicine.

And even though Pfizer subsequently added warnings to its package insert, the law firm alleged the drug label is still inadequate.

Pfizer introduced Chantix in the United States in 2006, with hopes it would become a huge product that would help revive flagging company profits, but its sales have wilted amid concern about side effects.

"Defendant intentionally, recklessly, and/or negligently concealed, suppressed, omitted, and/or misrepresented the risks, dangers, defects and disadvantages of Chantix," attorney Marc Grossman alleged in all three lawsuits.

Grossman is with the Mineola, New York law firm of Sanders Viener Grossman LLP.

Pfizer could not immediately be reached for comment.

Gene map for malaria crop offers higher yield hope

noreply@blogger.com (Medicine Hut) — Fri, 15 Jan 2010 14:35:00 +0000

LONDON (Reuters) - The first genetic map of a medicinal herb used in the best malaria treatments is being published to help scientists develop the species into a high-yielding crop and battle the killer mosquito-borne disease.

British plant researchers said the Artemisia annua gene code will enable scientists to select the best-performing young plants by genetics and use them as parent plants for breeding experiments without needing to take the more time-consuming approach of genetic modification (GM).

"The map is already proving to be an essential tool for us. With our new understanding of Artemisia genetics, we can produce improved, non-GM varieties...much faster than would otherwise be possible," said Dianna Bowles of York University's center for novel agricultural products (CNAP), whose work was published in the Science journal on Thursday.

Artemisinin, derived from the sweet wormwood, or Artemisia annua plant, is the best drug available against malaria, especially when used in artemisinin combination therapy (ACT) medicines made by firms such as Swiss drugmaker Novartis AG and France's Sanofi-Aventis.

Around 40 percent of the world's population is at risk of malaria, a potentially deadly disease transmitted via mosquito bites. It kills more than 1 million people worldwide each year and children account for about 90 percent of the deaths in the worst affected areas of sub-Saharan Africa and parts of Asia.

Experts say around 6,500 hectares of land -- most of it in China, Vietnam, Africa and India -- was devoted to sweet wormwood crops in 2009, producing 30 metric tonnes of artemisinin a year -- enough for around 60 million treatments.

Estimates vary on future needs, but most expect increased funding for malaria treatments to push demand for ACTS to at least 200 million a year in the coming two years.

But low artemisinin yields in the usual growing areas in Africa and Asia have made production expensive and planting areas have shrunk, raising fears of shortages and contributing to a slow roll-out of ACT treatments across the world.

CROP WOULD BE COMMERCIALLY VIABLE

Ian Graham, director of the CNAP, said scientists now had the molecular tools to develop the plant rapidly into a high-yielding crop that would be attractive and commercially viable for small-scale farmers in developing countries.

"It's combining modern-day molecular approaches with traditional plant breeding methods," he said in an interview.

"The next step...is to take those plants out to the developing world, to Africa, India and China and trial them and make sure they are robust enough to release to farmers."

The scientists said they hoped to get high-yielding seed to farmers in the next two to three years.

Crop scientists working at Britain's National Institute of Agricultural Botany said late last year they had trebled the yield of sweet wormwood plants and were keen to drug companies about their work. [ID:nGEE5B01SB]. Chinese scientists are also working to try to enhance the crop. [ID:nSP503140]

The World Health Organization said last month that increased funding was starting to pay off in the battle against malaria but greater efforts were needed to halt it.

Higher stroke, heart disease risks for A-bomb survivors

noreply@blogger.com (Medicine Hut) — Fri, 15 Jan 2010 14:34:00 +0000

HONG KONG (Reuters) - A study of atomic bomb survivors in Japan conducted over 53 years has found that they appear to suffer a far higher risk of heart disease and stroke because of their exposure to radiation.

The study, published in the British Medical Journal, involved 86,611 survivors from the bombings of Hiroshima and Nagasaki in 1945, which forced Japan into surrendering to the Allied Powers and officially ending World War Two.

Each person was exposed to an absorbed radiation dose of between 0 and 4 Gy (Gray) at the time of the bombings.

Gray is the unit measuring absorbed radiation dose using special equipment called dosimeters, and the amount varies from person to person depending on their location and shielding at the time of the bombings.

"This study provides the strongest evidence available to date that radiation may increase the rates of stroke and heart disease at moderate dose levels (mainly 0.5-2 Gy), though the results below 0.5 Gy are not statistically significant," said the researchers in Japan.

"Further studies should provide more precise estimates of the risk at low doses," they said.

The researchers said this was an important public health issue because of the increasing use of multiple computed tomography (CT) scans and other relatively high dose diagnostic medical procedures.

Medical use of radiation is typically measured in milligray (mGy). The average radiation dose from an abdominal x-ray is 1.4 mGy (0.0014 Gy), while that from an abdominal CT scan is 8.0 mGy (0.008 Gy), and that from a pelvic CT scan is 25 mGy (0.025 Gy).

Led by Yukiko Shimizu from the Radiation Effects Research Foundation in Japan, the scientists monitored the survivors from 1950 to 2003 and found that 9,600 died from stroke while 8,400 died of heart disease.

The researchers found an elevated risk of stroke and heart disease at doses above 0.5 Gy, and chances of these conditions occurring were more likely the higher the dose.

The scientists, however, said the consequence of low radiation doses was unclear and they recommended that future research should look into this.

Getting more than just an apple a day

noreply@blogger.com (Medicine Hut) — Fri, 08 Jan 2010 14:31:00 +0000

TORONTO (Reuters Health) - Less than a quarter of Americans eats the five daily servings of fruits and vegetables that the National Cancer Institute recommends, but online programs may help boost those numbers, a new study hints.

As part of the Making Effective Nutrition Choices study, some 2500 people logged on to a website providing information on the benefits of eating more fruits and vegetables and ways to incorporate these healthy foods into their diets.

Three months into the study about 70 percent of subjects were eating five or more servings of fruits and vegetables on an average day, up from 20 percent at the starting point. That increase held for the rest of the year-long study.

It was surprising to see such a large jump in the number of participants reaching the guidelines so early on, said study leader Dr. Christine Cole Johnson, and also to have those results hold for the next nine months. "In most nutritional studies, you're happy if you get a half-serving increase," Johnson said. But this study showed average increases of at least two servings daily.

Because the study included men and women aged 21 to 65 from around the country, the results indicate that a well-designed website could be used to educate more widely on the importance of fruit and vegetable consumption, Johnson said. "We think this could reach a large number of people and change habits on a national level," she said.

The results of the study are published in the latest issue of the American Journal of Public Health.

In the study, conducted at five U.S. sites, the researchers assessed change in fruit and vegetable intake associated with visiting a website that provided tailored nutritional information, with or without motivational emails, and an untailored "control" website.

The two websites had the same basic design, but the tailored website provided personalized nutritional information based on responses to a survey given at the outset, while the control site provided general information about nutrition related to fruits and vegetables. With the tailored website, "the messages they were given were based on concerns they had (about increasing consumption) and how to address those," Johnson said.

When the study began, the participants averaged 4.4 fruit and vegetable servings daily according to a 16-item "food frequency" questionnaire and 3.3 according to a 2-item questionnaire about average daily fruit and vegetable consumption.

By the end of the study, both questionnaires showed that daily fruit and vegetable consumption had increased by more than two servings, on average. Participants who accessed the tailored website showed comparable increases, whether or not they received email counseling, of about 2.7 servings daily, while those who used the generic website increased their daily servings by about 2.35.

The study participants reported an overall high level of satisfaction with the websites and the information they received on them, Johnson said. Statistically, it's hard to say what effect the motivational emails had on the results, she said, but study participants reported that they liked that feature and found it helpful.

Non-minority women over 50 with high levels of education were the most likely to stick with the program and increase their servings, the study found.

It was somewhat surprising, Johnson noted, that the web-based program was less popular with younger participants. Study co-author Dr. Gwen Alexander is currently working on a program aimed at younger participants. "It needs to be in front of them, accessible and easy," Alexander said.

Study turns up 10 autism clusters in California

noreply@blogger.com (Medicine Hut) — Fri, 08 Jan 2010 14:30:00 +0000

CHICAGO (Reuters) - U.S. researchers have identified 10 locations in California that have double the rates of autism found in surrounding areas, and these clusters were located in neighborhoods with high concentrations of white, highly educated parents.

Researchers at the University of California Davis had hoped to uncover pockets of autism that might reveal clues about triggers in the environment that could explain rising rates of autism, which affects as many as one in 110 U.S. children.

But the findings likely say more about the U.S. healthcare system than the causes of autism, said researcher Irva Hertz-Picciotto of UC Davis' MIND Institute, whose study will be released online on Wednesday in the journal Autism Research.

Advocacy groups have been clamoring for treatment options and for better research to show what might be causing an apparent increase in autism cases.

Hertz-Picciotto and colleagues used a research technique that has been effective at identifying cancer clusters.

"This kind of analysis sometimes turns up clues about environmental factors," she said in a telephone interview.

The researchers looked at about 2.5 million births recorded in California from 1996 through 2000. About 10,000 of those children were later diagnosed with an autism spectrum disorder, according to the state's department of developmental services.

Using data from birth records, the team found a strong link between parental education and the high rates of autism.

"In this particular case, we found 10 clusters of autism across the state of California. When we looked further, we discovered virtually all of them were areas where there was a higher level of education among the parents who were giving birth in those years," Hertz-Picciotto said.

"We already know that people with a higher education in the United States are more likely to get a diagnosis of autism for their child. It doesn't necessarily mean that autism occurs more frequently in those families," she said.

"It was also a greater likelihood to be white, non-Hispanic, and for the parents to be a little bit older."

ACCESS TO HEALTHCARE

Hertz-Picciotto said studies in Denmark, which offers universal access to healthcare, have found no link between autism and race or socioeconomic status.

"In this country, we have a lot of people who are uninsured. They may not have someone to go to if they have suspicions about their child," she said.

She said some communities with lower education levels and fewer resources may have higher rates of undiagnosed autism. But the study did offer new clues about autism.

"What it tells us is if we want to go looking for environmental factors, they are not going to be these focused fixed points of contamination, for example," she said.

"It is probably going to be something much more widespread -- common sorts of exposures that are more across the board."

Hertz-Picciotto said her team is now undertaking two different kinds of studies to look for environmental causes of autism, a spectrum of diseases ranging from severe and profound inability to communicate and mental retardation to relatively mild symptoms called Asperger's syndrome.

In one, her team plans to collect dust samples from the homes of 1,300 families with autistic children to look for common chemicals, such as flame retardants, that might be playing a role.

In another, the researchers are following pregnant women who have already given birth to a child with autism, to see if there are any common exposures that might be a factor in developing autism.

Inducing labor may lead to more C-sections

noreply@blogger.com (Medicine Hut) — Fri, 08 Jan 2010 14:30:00 +0000

NEW YORK (Reuters Health) - Pregnant women tempted to induce labor for convenience rather than medical necessity may want to wait for nature to take its course.

Dr. J. Christopher Glantz at the University of Rochester School of Medicine found that inducing labor introduces a risk of 1 to 2 cesareans per 25 inductions that might have been avoided by waiting for spontaneous labor to begin.

While this risk to individual women is not particularly large, Glantz told Reuters Health that 1 to 2 cesareans per 25 inductions can quickly add up to tens of thousands of unnecessary cesareans over the course of millions of inductions.

While the procedures have become more common, C-sections are major surgeries, and carry risk of infection, bleeding, blood clots, and injury to other organs, Glantz emphasizes in a report in the journal Obstetrics and Gynecology.

The researcher analyzed birth certificate data for some 38,000 women from 13 hospitals in the Finger Lakes region of New York State from January 2004 to March 2008. He excluded women with scheduled or previous cesarean deliveries, or who had come to the hospital with ruptured membranes.

While previous studies have already shown that induced labor increases the risk for cesarean, Glantz examined how that risk might shift given a redefined comparison group.

He examined C-section rates after induction using three comparison groups: a week-by-week comparison of women induced to labor compared with those delivering spontaneously; women induced at a chosen week compared with women who delivered spontaneously after that week; and women induced at a chosen week compared with women who delivered spontaneously on or after that week.

In a nutshell, the study found that all labor induced groups faced increased risk for C-section, except for those women delivering after 39 weeks.

Glantz advises that pregnant women and their doctors may be better off waiting for spontaneous labor. "Try to reserve interventions for situations where risk outweighs benefit," said Glantz, such as in cases of diabetes, high blood pressure, problems with the placenta, a baby that is not growing well, or a woman being 10 days past her due date.

Easing H1N1 pandemic may let in new flu viruses

noreply@blogger.com (Medicine Hut) — Fri, 08 Jan 2010 14:29:00 +0000

LONDON (Reuters) - The declining wave of pandemic H1N1 flu is likely to be followed by new, unknown strains of seasonal flu which health authorities must watch carefully to devise protection measures, European flu experts said on Friday.

The European Center for Disease Prevention and Control (ECDC) warned that flu viruses "never stand still" and said governments should not relax H1N1 flu vaccination programs, but remain on guard for possible changes in the virus and new strains.

"The historical pattern of human influenzas is that after pandemics, the world experiences a new mix of viruses," the ECDC's flu expert Angus Nicoll wrote in the Eurosurveillance scientific journal.

In a telephone interview, Nicoll said although signs from many parts of Europe and the United States suggest circulation of H1N1 is declining, it is still too early to say the pandemic is over.

He noted that the virus responsible for the last pandemic in 1968-70 became more easily transmitted between its first and second winter, so that there were more cases and deaths in the second winter (1969-70) in at least two European countries.

An earlier pandemic in 1957-58 also declined before Christmas 1957, but then came back to cause a rise in flu-related deaths in the new year of 1958.

In the current pandemic, new infections of H1N1 flu have fallen sharply in recent weeks and some governments have been left with an oversupply of vaccines ordered to protect their populations against the virus that emerged last March.

Uptake of the vaccine has been limited in some countries and advice from medical experts that one dose is enough to protect against the virus, rather than the two originally anticipated, means some governments have more than they need.

Latest data from the ECDC, which monitors disease in the European Union, show that H1N1 -- also known as swine flu -- has killed more than 11,600 people around the world, more than 2,000 of them in Europe.

Nicoll said pandemic H1N1 flu had not completely halted other flu viruses in recent months, but had been the predominant strain, meaning that its decline could open the way for a new mix of viruses known as inter-pandemic or seasonal flus.

He said governments should continue to urge people to get vaccinated against H1N1, since the shots were "the most potent countermeasure" for any human flu.

"The rule with influenza, pandemic and inter-pandemic, is to maintain vigilance and expect the unexpected," he said.

Nicoll also said some H1N1 vaccines, which governments ordered from drugmakers like GlaxoSmithKline, AstraZeneca, Sanofi-Aventis, Novartis and Baxter, among others, may prove useful in warding off any new strains of seasonal flu that emerge in the wake of the pandemic.

"Countries should see through what they planned to do," he said. "And one of the good things about some of the vaccines that European countries are using is that they have adjuvants (or boosters), which it makes it much more likely that they can cope with a virus that changes."

Cocaine changes how genes work in brain

noreply@blogger.com (Medicine Hut) — Fri, 08 Jan 2010 14:29:00 +0000

CHICAGO (Reuters) - Prolonged exposure to cocaine can cause permanent changes in the way genes are switched on and off in the brain, a finding that may lead to more effective treatments for many kinds of addiction, U.S. researchers said on Thursday.

A study in mice by Ian Maze of Mount Sinai School of Medicine in New York and colleagues found that chronic cocaine addiction kept a specific enzyme from doing its job of shutting off other genes in the pleasure circuits of the brain, making the mice crave the drug even more.

The study helps explain how cocaine use changes the brain, said Dr. Nora Volkow, director of the National Institute on Drug Abuse, part of the National Institutes of Health, which funded the study published in the journal Science.

"This finding is opening up our understanding about how repeated drug use modifies in long-lasting ways the function of neurons," Volkow said in a telephone interview.

For the study, the team gave one group of young mice repeated doses of cocaine and another group repeated doses of saline, then a single dose of cocaine.

They found that one way cocaine alters the reward circuits in the brain is by repressing gene 9A, which makes an enzyme that plays a critical role in switching genes on and off.

Other studies have found that animals exposed to cocaine for a long period of time undergo dramatic changes in the way certain genes are turned on and off, and they develop a strong preference for cocaine.

This study helps explain how that occurs, Volkow said, and may even lead to new ways of overcoming addiction.

In the study, Maze and colleagues showed these effects could be reversed by increasing the activity of gene 9A.

"When they do that, they completely reverse the effects of chronic cocaine use," Volkow said.

She said this mechanism is likely not confined to cocaine addiction, and could lead to a new area of addiction research for other drugs, alcohol and even nicotine addition.

"One of the questions we've had all along is, after discontinuing a drug, why do you continue to be addicted?

"This is one of the mechanisms that probably is responsible for these long-lasting modifications to the way people who are addicted to drugs perceive the world and react to it," she said.

Report calls for research on nanoparticles in food

noreply@blogger.com (Medicine Hut) — Fri, 08 Jan 2010 14:26:00 +0000

LONDON (Reuters) - A global scarcity of scientific research on using nanotechnology in foods means food safety authorities are unable to properly regulate products that may be beneficial or harmful, a British science panel said on Friday.

The science and technology committee of Britain's upper house of parliament said in a report that use of nanoparticles in food and food packaging is likely to grow dramatically in the next decade, but too little is known about their safety.

"The technologies have the potential to deliver some significant benefits to consumers, but it is important that detailed and thorough research into potential health and safety implications ... is undertaken now to ensure that any possible risks are identified," said Lord Krebs, chair of the Science and Technology Committee which produced the report.

Nanotechnology is the design and manipulation of materials thousands of times smaller than the width of a human hair, called nanoparticles.

The technology has been hailed as a new way to make stronger and more lightweight materials, better cosmetics and tastier or healthier foods, but Friday's report said a paucity of scientific research across the world meant its potential benefits and risks in food were largely unknown.

According to Krebs whose committee heard evidence from food producer groups, regulators and scientific experts from across the world, the global market for nanotechnology in food was $410 million in 2006 and is set to grow to $5.6 billion in 2012.

"We are on the cusp of a potentially explosive growth in this novel approach to food manufacture and processing," he told a news briefing.

There are currently at least 600 products involving nanomaterials on the market but only around 80 of them are food or food-related and only two of those are available in the UK.

The report called for new rules to compel food companies to tell regulators about any work they are doing with nanoparticles in food, and also called for a voluntary public register of food products and packaging containing nanomaterials available.

Krebs said the food industry in Britain and worldwide was being "quite obscure" about any work they are doing on using nanotechnology for products or packaging -- an attitude he described as "exactly the wrong approach".

"The food industry must be much more open with the public about research it has undertaken in this area and where it sees nanomaterials being used in food production in future," he said.

Stephen Holgate, a clinical professor of immunopharmacology at the University of Southampton, who advised the committee on its report, said some studies suggest nanoparticles behave differently in the body than larger ones.

"Most of the research so far... has shown that these particles can penetrate barriers and get into the system -- and they can find their way into the liver, into the kidney and even into the brain," he told reporters. "Knowing that, we really need now to concentrate on finding out what their effects are."

The report's authors warned that the lessons of a public backlash against genetically modified food in Europe showed that "secrecy breeds mistrust, and that openness and transparency are crucial to maintain public confidence." (REUTERS)

Sudden death after arrest

noreply@blogger.com (Medicine Hut) — Wed, 03 Sep 2008 06:45:00 +0000

Young men who die suddenly after being arrested by the police may be victims of a new syndrome similar to one that kills some wild animals when they are captured, Spanish researchers said on Tuesday.

Manuel Martinez Selles of Madrid's Hospital Gregorio Maranon reached the conclusion after investigating 60 cases of sudden unexplained deaths in Spain following police detention.

In one third of the cases, death occurred at the point of arrest, while in the remainder death was within 24 hours, Selles told the annual meeting of the European Society of Cardiology.

All but one of the casualties were male and their average age was just 33 years, with no previous history of cardiovascular disease.

"Something unusual is going on," Sells said.

Just why they died remains a mystery but he believes young men, in particular, may experience surges in blood levels of chemicals known as catecholamines when under severe stress.

Adrenaline is one of the most abundant catecholamines.

"We know that when a wild animal is captured, sometimes the animal dies suddenly," he said.

"Probably when these young males are captured it is very stressful and their level of catecholamines goes very high and that can finish their life by ventricular fibrillation (cardiac arrest)."

Selles compiled his study -- the first of its kind in any country -- by scouring Spanish newspapers for cases of unexplained death after police detention over the past 10 years.

Only sudden deaths with no clear causes were included and autopsy reports were checked to exclude the possibility of mistreatment or past serious medical conditions.

Twelve of the victims were drug users but Selles said this was not thought to have contributed to their deaths.

Jonathan Halperin of the Mount Sinai Medical Center in New York, who was not involved in the research, said the concept of a heart stress syndrome triggered by a flood of adrenaline or other chemicals was "a reasonable hypothesis".

"We all know stress is bad for you and this may be stress in the extreme," he said.

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Early weight gain may lead to hypertension

noreply@blogger.com (Medicine Hut) — Wed, 03 Sep 2008 06:44:00 +0000

Babies who gain weight rapidly in the first months after birth may have an increased risk of developing high blood pressure as adults, British researchers said on Tuesday.

Researchers have been trying to understand more of the causes of high blood pressure, also called hypertension. Low birth weights also have been associated with an increased risk for high blood pressure later in life.

The new study sought to determine if growth patterns in the first five years of life also were associated with a risk of high blood pressure in adulthood. The researchers tracked 679 young adults around age 25 in Britain.

They found that those who gained weight more rapidly in the first five months after birth and again from about age 2 to 5 were more likely to have high systolic blood pressure.

Immediate weight gain after birth also was linked to higher adult diastolic blood pressure, they found.

Systolic blood pressure is the pressure in the arteries while the heart contracts. Diastolic blood pressure is the pressure when the heart relaxes between beats.

"When trying to understand why some people get high blood pressure in later life, we need to consider a life course approach that considers early life as well as adult life risk factors such as dietary salt and obesity," Yoav Ben-Shlomo of the University of Bristol in Britain, who led the study published in the journal Hypertension, said in a statement.

High blood pressure -- sometimes called the "silent killer" because it can go undetected for years -- raises a person's risk of heart disease and stroke.

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Gastric bypass anatomy leads to diabetes control

noreply@blogger.com (Medicine Hut) — Wed, 03 Sep 2008 06:43:00 +0000

The rapid and substantial control of diabetes seen after gastric bypass surgery is due, at least in part, to the intestinal rearrangement involved in the procedure, the results of an animal study suggest.

Besides removing a substantial portion of the stomach, gastric bypass also attaches the output of the stomach to the lower intestines. The lower portion of the gut usually produces little glucose, but because of the direct input from the stomach it increases its production, French researchers report in the research journal Cell Metabolism.

The liver senses the higher level of glucose and reduces its own production of the sugar. Since the liver contributes much more to the body's overall glucose production than do the intestines, the net effect is enhanced glucose control, say Dr. Gilles Mithieux, from Universite de Lyon, and colleagues.

The increase in intestinal glucose formation was only noted with gastric bypass, not with gastric banding, which doesn't re-route the intestines. This may explain why only gastric bypass has been associated with enhanced diabetes control, the investigators conclude.

Furthermore, they note, sensors in the liver detect the elevated glucose and send an appetite-suppressing signal to the brain, which contributes to the satiety and weight loss seen with gastric bypass.

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Virus is passed from parent to child in the DNA

noreply@blogger.com (Medicine Hut) — Wed, 03 Sep 2008 06:43:00 +0000

A virus that causes a universal childhood infection is often passed from parent to child at birth, not in the blood but in the DNA, U.S. researchers said on Tuesday.

They found that most babies infected with the HHV-6 virus, which causes roseola, had the virus integrated into their chromosomes. Not only that, but either the father or mother also had the virus in the chromosomes, suggesting it was a so-called germline transmission -- passed on in egg or sperm.

"This is really a unique mechanism for congenital infections," said Dr. Caroline Breese Hall, a pediatrician at the University of Rochester Medical Center in New York who led the study published in the journal Pediatrics.

Her team is now investigating what this means for the children.

"If you have a chromosome that has got a virus integrated into it, what does it mean? What does it do? Can it activate again? Can it start spewing out virus and cause problems? Can you get an immune response to it?" she said in a telephone interview.

The questions are critical because nearly everybody is infected with HHV-6. It is a herpes virus that causes roseola -- an infection marked by high fever and the usual vague virus symptoms that may include respiratory or stomach problems.

About 20 percent of children also have a characteristic sudden rash that appears just as the fever breaks.

Hall's team studied 250 infants, 85 with HHV-6. Of them, 43 were born with the virus and 42 were infected later.

Most of the babies born with the virus -- a congenital infection -- had the virus in the chromosome. Hall said the assumption had been that the virus somehow crossed the placenta from mother to child, but in 86 percent of cases, it was inherited directly in the genetic material.

Just 14 percent were infected across the placenta.

Tests showed either the mother or the father -- but not both -- also had HHV-6 in the chromosomes.

"Because we know a parent already had the virus in the chromosome, we know that it didn't spontaneously wiggle its way in once the baby got it," Hall said.

There were several spots where the virus integrated into the DNA, but usually right at the end of the chromosome, where a key structure called the telomere is found. Telomeres protect the chromosome and are involved in aging and immune response.

The virus is everywhere in people who inherit it, Hall said. "In your hair, your nails, your skin, your blood, and at very high titers (levels)," she said.

The babies infected this way did not appear ill but Hall wants to follow them as they grow up to see if they develop normally. They all had antibodies to HHV-6, which is evidence of an immune reaction of some sort.

There is no drug licensed to treat HHV-6 infection.

Other viruses are known to integrate into the DNA and pass on from parent to child, but these so-called human endogenous retroviruses have never been known to cause symptoms or activate an immune response.

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Exercise may improve memory in older people

noreply@blogger.com (Medicine Hut) — Wed, 03 Sep 2008 06:42:00 +0000

Regular, moderate exercise may help improve memory in older people and delay the onset of dementia, a study in Australia shows.

The study, published in the Journal of the American Medical Association, involved 170 participants aged 50 and over who reported some memory trouble but who did not have dementia.

Half engaged in moderate exercise, such as walking, for 50 minutes three times a week, while the others did no exercise.

After six months, the participants were given memory and other tests, including recalling lists of words. Those who exercised fared markedly better than those who did not.

"The trial is the first to demonstrate that exercise improves cognitive function in older adults with subjective and objective mild cognitive impairment," according to the report.

"The benefits of physical activity were apparent after 6 months and persisted for at least another 12 months after the intervention had been discontinued."

With the ageing of populations everywhere, an estimated 37 million people worldwide now live with dementia, with Alzheimer's disease making up the majority of cases, according to the World Health Organization.

That figure is expected to increase rapidly over the next 20 years and researchers are looking for ways to help delay the onset of dementia.

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High blood calcium tied to lethal prostate cancer

noreply@blogger.com (Medicine Hut) — Wed, 03 Sep 2008 06:41:00 +0000

Men with elevated levels of calcium in their blood may have a much higher risk of getting fatal prostate cancer, U.S. researchers said on Wednesday.

The findings indicate that a simple blood test may identify men at high risk for the most dangerous prostate tumors, and there already are drugs available that cut calcium levels in the bloodstream, the researchers said.

They tracked 2,814 men in a government health survey in which they gave blood samples that revealed calcium levels.

The men in the top third of blood calcium levels had 2.68 times the risk of developing fatal prostate cancer later in life compared to those in the bottom third, the study found.

"If serum calcium really does increase your risk for fatal prostate cancer, that's wonderfully exciting because serum calcium levels can be changed," Gary Schwartz of Wake Forest University School of Medicine, who helped lead the study, said in a telephone interview.

"One way to think of it is to think of the tremendous advances in the control of cardiovascular disease that occur from understanding that things like serum cholesterol predict heart attack," Schwartz added.

Doctors have struggled to find ways to predict if a man who gets prostate cancer will have a tumor that poses little danger, as is often the case, or one that is a killer.

Blood calcium was not very predictive of whether a man would get nonlethal prostate cancer, but was highly predictive of whether a man would get a fatal case, the researchers wrote in the American Association for Cancer Research's journal Cancer Epidemiology, Biomarkers & Prevention.

The blood samples on average were given a decade before the cancer appeared, the researchers said.

A COMMON CANCER

Prostate cancer is the second most commonly diagnosed form of cancer in men worldwide, with about 780,000 men diagnosed per year, and the sixth mostly deadly form in men, with about 250,000 deaths per year, the American Cancer Society said.

Schwartz said it is unclear whether it is the actual calcium or blood levels of parathyroid hormone, which is supposed to keep calcium levels at normal levels in the bloodstream, that is raising the risk.

Either way, he said there are drugs that can lower them, including Fontus Pharmaceuticals Inc's Rocaltrol, also called calcitriol; Genzyme Corp's Hectorol (doxercalciferol); Abbott Laboratories' Zemplar (paricalcitol); and Amgen Inc's Sensipar (cinacalcet).

People treated for high blood calcium usually have chronic kidney disease, which is associated with low vitamin D levels. Low vitamin D levels elevate parathyroid hormone levels, Schwartz said.

Halcyon Skinner of the University of Wisconsin, who also worked on the study, said there is little relationship between calcium in the diet and blood calcium levels, so these men would not benefit from eating less food rich in calcium.

Previous research had suggested a role for calcium in prostate cancer. In laboratory studies, parathyroid hormone and calcium promote the growth of prostate cancer cells.

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High doses of vitamin D safe for children

noreply@blogger.com (Medicine Hut) — Mon, 01 Sep 2008 21:08:00 +0000

Giving school children very high doses of vitamin D is safe, and may be necessary to bring their blood levels of the nutrient up to the amount necessary for optimum bone growth and health, a new study shows.

Insufficiency in vitamin D is common in children around the world, but there is little data on how much supplementation kids need, or even how much vitamin D they should have in their blood, Dr. Ghada E.-Hajj Fuleihan of the American University of Beirut in Lebanon told Reuters Health. "In the pediatric literature, we don't have a lot to guide us," she said.

In a previous study, Fuleihan and colleagues found that giving 10- to 17-year-olds relatively high doses of vitamin D3 increased their bone mass and bone area, as well as lean mass. In the current study, they report on both the short- and long-term safety of high-dose supplementation.

The short-term study included 25 school children randomly assigned to receive a placebo or 14,000 international units (IU) of vitamin D3 per week for eight weeks. In the long-term study, 340 study participants took placebo, 1,400 IU weekly, or 14,000 IU a week, and were followed up at six and 12 months.

Currently, the Institute of Medicine recommends a daily vitamin D3 intake of 200 IU for children. The high dosage used in the current study was 2,000 IU daily, or 10 times that amount.

No signs of vitamin D intoxication were seen in any of the children, while levels of the vitamin in children treated short-term rose from 44 to 54 nanograms per milliliter (ng/mL).

In the long-term study, levels rose from 15 to 19 ng/mL in children given 1,400 IU weekly and from 15 to 36 ng/mL in the higher-dose group. Levels were initially higher in the short-term study because it was conducted among children in a higher socioeconomic group, and took place in the summer, when kids are likely to get ample sunshine and thus have adequate blood levels of the vitamin, Fuleihan and her team explain in the Journal of Clinical Endocrinology and Metabolism.

Based on studies in adults, Fuleihan said, blood levels of vitamin D below 5 ng/mL are agreed to represent deficiency, while levels above 20 ng/mL are considered adequate and most experts say 30 ng/mL is ideal.

Because every additional 100 IU of vitamin D3 consumed produces a roughly 1 ng/mL increase in blood levels, high doses may be needed for children with vitamin D insufficiency, the researcher said.

Nevertheless, she added, more research is needed to understand how much vitamin D children should be getting, and whether there are health effects of vitamin D insufficiency beyond bone and muscle, as studies in adults suggest.

"The pediatric literature is lagging maybe 10 to 15 years behind the adult literature in understanding the impact of low vitamin D on health," the researcher said.

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Lack of joy in life ups early death risk

noreply@blogger.com (Medicine Hut) — Mon, 01 Sep 2008 21:07:00 +0000

People who don't think life is worth living are more likely to die within the next few years, research from Japan shows.

The increased death risk was mainly due to cardiovascular disease and external causes --most commonly, suicide.

The research is the largest to date to investigate how "ikigai," or "joy and a sense of well-being from being alive," affects mortality risk, and only the second to examine death from specific causes, according to Dr. Toshimasa Sone and colleagues from the Tohoku University Graduate School of Medicine in Sendai.

The investigators looked at 43,391 men and women 40 to 79 years old living in the Ohsaki region who were followed for seven years, during which time 3,048 died. All were asked, "Do you have ikigai in your life?" Fifty-nine percent said yes, 36.4 percent said they weren't sure, and 4.6 percent said no.

Those who didn't have a sense of ikigai were less likely to be married or employed, and were also less educated, in worse health, more mentally stressed, and in more bodily pain. They were also more likely to have limited physical function.

But even after the researchers used statistical techniques to adjust for these factors, people with no sense of ikigai were still at increased risk of dying over the follow-up period compared to people who did have ikigai. The relationship also was independent of history of illness and alcohol use.

Overall, people with no sense of ikigai were 50 percent more likely to die from any cause during follow-up compared to those who did have a sense that life was worth living. They had a 60 percent greater risk of death from cardiovascular disease, most commonly stroke, and were 90 percent more likely to die of "external" causes.

Of the 186 deaths due to external causes among study participants, 90 were suicides.

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Kids with older dads at higher bipolar risk

noreply@blogger.com (Medicine Hut) — Mon, 01 Sep 2008 21:06:00 +0000

Children born to fathers older than 30 are more likely to develop bipolar disorder, a common condition sometimes known as manic depression, researchers reported on Monday.

The paternal risk also grows with the age of a father, rising to 37 percent by the time a man is 55 years, said Emma Frans, an epidemiologist at the Karolinska Institute in Sweden, who led the study.

The brain disorder causes extreme shifts in mood, energy and ability to function. It is marked by high periods of elation or irritability and low periods of sadness and hopelessness that can last months.

The findings published in the Archives of General Psychiatry bolster evidence that children of older fathers are at higher risk of psychological conditions such as bipolar disorder, autism and schizophrenia, the researchers said.

"Advanced paternal age is a risk factor for bipolar disorder in the offspring," Frans and colleagues wrote.

One explanation could be that a man's degraded sperm quality as he ages could increase the likelihood of genetic mutations that may lead to biopolar disorder, Frans said.

"Despite the robust evidence supporting the association between paternal age and severe mental disorders, the association between advanced paternal age and bipolar disorder has not been investigated," the team added.

The findings are another step toward unraveling the mystery of how the condition affecting an estimated 1 percent to 3 percent of adults worldwide arises, the researchers said.

Last month, an international research team linked two genetic variants to an increased risk for the disease, which is often treated with AstraZeneca Plc's blockbuster drug Seroquel. The condition often runs in families.

The Swedish researchers used a national medical registry to identify nearly 14,000 men and women diagnosed with bipolar disorder. For each person, they also randomly selected five people of the same sex and age without the condition.

After factoring for maternal age, the researchers found that children born to fathers older than 30 had an 11 percent higher risk of developing bipolar disorder compared to younger fathers. Children whose fathers were older than 55 had a 37 percent increased risk.

Frans said the findings did not mean that older men should not father children because the overall risk is still low, she added.

"The study sheds light on the negative effect of older fathers but most older men will still have healthy children," she said in a telephone interview.

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Study finds more allergic reactions after HPV jab

noreply@blogger.com (Medicine Hut) — Mon, 01 Sep 2008 21:05:00 +0000

Young women in Australia who got a vaccine to prevent cervical cancer were five to 20 times more likely to have a rare but severe allergic reaction than girls who got other vaccines in comparable school-based vaccination programs, researchers said on Monday.

They said the severe allergic reactions to the human papillomavirus or HPV vaccine were unusual and manageable and that the vaccine remained safe.

The team of Australian researchers led by Dr. Julia Brotherton of The Children's Hospital at Westmead studied 114,000 young women vaccinated with Merck & Co's Gardasil vaccine as part of a 2007 vaccination program in New South Wales.

Of these, 12 had suspected cases of anaphylaxis, a potentially life-threatening allergic reaction that can cause difficulty breathing, nausea and rashes, they reported in the Canadian Medical Association Journal.

Eight out of the 12 young women had confirmed anaphylactic reactions after getting the vaccine, for an estimated rate of reaction of 2.6 per 100,000 doses administered. That compared with a rate of 0.1 per 100,000 doses in a 2003 school-based meningitis vaccination program.

Brotherton and colleagues suspect the higher rates of allergic reaction could be due to better surveillance programs to watch for such reactions, the higher tendency for young women to have such reactions compared with men and an apparent overall rise in the incidence of anaphylaxis in Australia.

Nevertheless, they said that the rates remain rare and should not discourage use of the vaccine, which targets four strains of the human papillomavirus, a common sexually transmitted virus that causes genital warts and most cases of cervical cancer.

"It's just a reminder that there are rare adverse effects," said Dr. Neal Halsey of Johns Hopkins University in Baltimore, who wrote a commentary on the study.

"It doesn't change the strong recommendations for all adolescent girls to get this vaccine but we just have to watch them to make sure they don't have this allergic reaction," he said in a telephone interview.

Last May, the U.S. Centers for Disease Control and Prevention said Gardasil has been associated with a higher risk of fainting, in some cases resulting in injury.

In the United States, Merck has distributed more than 16 million doses of Gardasil, which is approved for women and girls ages 9 to 26.

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High birth weight may raise brain tumor risk

noreply@blogger.com (Medicine Hut) — Mon, 01 Sep 2008 21:04:00 +0000

Babies who are heavy at birth -- weighing more than 4000 grams (8.8 pounds) -- may have an increased risk for two of the most common types of brain tumors among children, German researchers report.

Astrocytomas, which form in the large cells of the nervous system, and medulloblastomas, which generally develop in the central part or within the hemispheres of the brain, account for up to about half of childhood brain tumors, note Dr. Thomas Harder and colleagues at Charite-Universitatsmedizin Berlin.

"Remarkably, for both of these types of childhood brain cancer ... high birth weight was significantly associated with increased tumor risk," Harder and colleagues report in the American Journal of Epidemiology.

The investigators found this association after looking at the combined findings from eight studies that involved more than 1.7 million children younger than 19 years old. Over 4000 of these children developed astrocytomas, medulloblastomas, or tumors in the cerebrospinal passageways of the brain known as ependymomas.

In studies reporting the development of astrocytomas, the researchers found that each 1000 gram (2.2 pound) increase in birth weight increased risk by 19 percent.

Studies reporting the development of medulloblastomas also showed a significantly increased risk among children who were heavy at birth, but risk did not appear to increase with increasing birth weight, as found with astrocytomas, the investigators note.

By contrast, they found no association between low birth weight and the development of these two tumor types; nor did they identify a link between birth weight and the development of ependymomas in the small number of studies reporting on this type of tumor.

Should follow up research find causal associations between high birth weight and childhood cancers, measures to decrease the incidence of high birth weight may be needed to curb the risk for brain tumors in children, Harder and colleagues conclude.

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B vitamins fail to curb risks in heart patients

noreply@blogger.com (Medicine Hut) — Wed, 20 Aug 2008 17:49:00 +0000

Reducing levels of the amino acid homocysteine with folic acid and B vitamins failed to prevent serious complications in patients with heart disease, Norwegian researchers said on Tuesday.

The study was the latest of several large trials to show that lowering homocysteine through vitamin therapy offered no benefit to people with heart disease.

Other research had found a link between high concentrations of homocysteine in the blood and heart attacks and strokes.

But the researchers said the failure of their study and others like it suggests that homocysteine may be a marker for heart risks, and not a cause.

"Our findings do not support the use of B vitamins as secondary prevention in patients with coronary artery disease," Dr. Marta Ebbing of Haukeland University Hospital in Bergen, Norway, and colleagues wrote in the Journal of the American Medical Association.

Ebbing's team studied 3,096 patients with coronary artery disease in two Norwegian hospitals between 1999 and 2006 who were having procedures to remove blood clots that were blocking the flow of blood to the heart.

They divided patients into four groups, testing different combinations of B6 and B12 vitamins with or without folic acid. The vitamins were given in addition to other treatments.

Patients were scheduled for follow-up visits with an interview, clinical examination and blood sampling at one month, one year, and at a final study visit.

The study was stopped early because preliminary results from a similar study in Norway found no benefits from the therapy and an increased risk of cancer associated with B vitamins.

Based on the data they collected, Ebbing and colleagues found no sign that a combination of folic acid plus vitamin B12 or B6 helped reduce the risk of death or major heart events, such as heart attacks or strokes.

They did find a trend toward fewer strokes and a higher risk of cancer in groups receiving folic acid, but they said the numbers were not statistically significant.

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Prostate enlargement treated by Impotence Drug

noreply@blogger.com (Medicine Hut) — Wed, 20 Aug 2008 17:48:00 +0000

Impotence drugs may be able to help reduce the symptoms caused by enlarged prostates, such as trouble urinating, U.S. researchers reported on Tuesday.

Men who took Eli Lilly and Co's Cialis every day had fewer symptoms, such as urinary frequency, urgency, intermittence, straining, incomplete emptying or a weak urinary stream, they reported in the journal Urology.

With about 50 percent of men over 50 suffering from some version of this problem, the study suggests a large potential market for erectile dysfunction drugs.

Researchers at the University of Texas Southwestern Medical Center at Dallas, Northwestern University in Chicago and Lilly Research Laboratories tested more than 1,000 men with enlarged prostates -- a condition known as benign prostatic hyperplasia or BPH.

Some got various doses of Cialis, known generically as tadalafil, while some got a placebo. Those who got Cialis were more likely to report their symptoms had improved, and a relatively low dose of 5 mg a day did the trick, reported the researchers, led by UTSW's Dr. Claus Roehrborn.

Cialis caused relatively few side effects, they added, in contrast to the drugs now used to treat BPH.

"Although they are effective, each of these drug classes can produce unwanted side effects, including dizziness, hypotension (low blood pressure) and sexual dysfunction," they wrote.

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