Exercise Really Can Make You Younger, Study Shows

The study suggests that 30 minutes of moderate exercise five times a week has significant benefits

People who take exercise are biologically younger - by up to nine years - than those who don’t.

This striking finding may explain why exercise reduces the risk of heart attacks, diabetes, cancer, and other degenerative diseases. It actually suggests that active adults have cells that are measurably “younger” than those of inactive ones.

A team from King’s College London looked at biological molecules called telomeres that act as a clock, measuring the passage of the years. Telomeres are the caps at the end of the chromosomes, designed like the tips of a shoelace to protect them from damage.

In youth, telomeres are long, but they get shorter as we age, leading to a growing risk of damage. In the new study published in Archives of Internal Medicine the King’s team, together with colleagues from New Jersey, have shown that active people have longer telomeres than inactive ones.

They used data from the Twin Research Unit at King’s College to compare identical and non-identical twins, whose average age was just under 50. The study included more than 2,400 volunteers - mostly women - with an age range from 18 to 81.

Professor Tim Spector and Dr Lynn Cherkas from King’s, and Professor Abraham Aviv of New Jersey Medical School, asked the volunteers to fill in questionnaires about the amount of exercise they had done in the previous year. They also established whether they were smokers, their body mass index (BMI), and their socioeconomic status.

They found there was a significant link between telomere length in the volunteers’ white blood cells and the amount of exercise they took. This remained significant when adjusted for smoking, BMI, and social class.

Because genes also influence telomere length, the team checked the results by looking at a smaller group of identical twins. These pairs shared the same genes, but differed in their levels of everyday activity.

This confirmed that the link between telomere length and activity is also found in identical twins - powerful evidence that there is more to it than genetics.

The actual difference between active and inactive people was quite large. Dr Cherkas said: “Overall, the difference in telomere length between the most active subjects and the inactive subjects corresponds to around nine years of ageing.”

The team concludes: “The US guidelines recommend that 30 minutes of moderate-intensity physical activity at least five days a week can have significant health benefits.

“Our results underscore the vital importance of these guidelines. They show that adults who partake in regular physical activity are biologically younger than sedentary individuals.”

Professor Spector said: “Our study, performed on a large cohort, indicates that differences in telomere length between active and inactive individuals cannot be explained by variations in genes, smoking, BMI and socioeconomic status.

“A sedentary lifestyle appears to have an effect on telomere dynamics – thus providing a powerful message that could be used by clinicians to promote the potentially anti-aging effect of regular exercise.’

In a commentary in the same journal, Dr Jack Guralnik of the US National Institute on Ageing, says the results are provocative, but that more research is needed to prove them true.

“Persons who exercise are different from sedentary persons in many ways, and although certain variables were adjusted for in this analysis, many additional factors could be responsible for the biological differences between active and sedentary persons” he writes.

“Nevertheless, this article serves as one of many pieces of evidence that telomere length might be targeted in studying ageing outcomes.

Source: www.timesonline.co.uk

Diuretics Best for Hypertension and Metabolic Syndrome

Diuretics appear to be as good or better than other blood pressure drugs for treating hypertension in patients with metabolic syndrome, especially black patients, according to a U.S. study.

People with hypertension and metabolic syndrome are at high risk for complications of cardiovascular disease.

Researchers at Case Western Reserve University and University Hospitals Cases Medical Center in Cleveland analyzed data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).

It included 42,418 people with hypertension and at least one other risk factor for cardiovascular disease who were randomly assigned to take either the diuretic chlorthalidone (15,255), the calcium channel blocker amlodipine besylate (9,048), the alpha-blocker doxazosin mesylate (9,061), or the ACE inhibitor lisinopril (9,054).

Each drug was used to start treatment, and other drugs were added if necessary to control blood pressure. The majority of patients were followed for an average of 4.9 years, but the alpha-blocker part of the trial was halted after an average of 3.2 years due to increased rates of cardiovascular disease.

Among the patients in the study, 23,077 met the criteria for metabolic syndrome, which is defined as hypertension plus at least two of the following factors: diabetes or pre-diabetes; a body-mass index (BMI) of at least 30; high triglyceride levels; or low levels of high-density lipoprotein ("good" cholesterol).

"No differences were noted among the four treatment groups, regardless of race or metabolic syndrome status for the primary end point (nonfatal myocardial infarction [heart attack] and fatal coronary heart disease)," the study authors wrote.

Among patients with metabolic syndrome, those taking the diuretic had a lower rate of heart failure than those taking the other three drugs. Patients who took the ACE inhibitor and the alpha-blocker also had an increased risk of combined cardiovascular disease.

"The lack of benefit of the agents with the most favorable metabolic profile [i.e., ACE inhibitors and alpha-blockers] was especially marked in black participants with metabolic syndrome," the researchers wrote.

"The magnitude of excess risk of end-stage renal [kidney] disease [70 percent], heart failure [49 percent] and stroke [37 percent] and the increased risk of combined cardiovascular disease and combined coronary heart disease strongly argue against the preference of ACE inhibitors over diuretics as the initial therapy in black patients with metabolic syndrome. Similar high risk was noted for those randomized to the alpha-blocker versus the diuretic."

The researchers concluded that the findings "fail to provide support for the selection of alpha-blockers, ACE inhibitors, or calcium channel blockers over thiazide-type diuretics to prevent cardiovascular or renal outcomes in patients with metabolic syndrome, despite their more favorable metabolic profiles."

Source: www.washingtonpost.com

Critical Things to Know about Your Cholesterol

How's your cholesterol? Here's a guess: If you're healthy, you probably have no idea. New surveys show women tend to be clueless about their risks of heart disease, especially when it comes to managing their cholesterol.

High cholesterol can lead to clogged coronary arteries, which can cause heart attack and stroke.

But this kind of ignorance is anything but bliss. The reason: The artery clogging that makes heart disease the Number One killer of women late in life begins much earlier - in your 20s, 30s, and 40s - and that's when your cholesterol numbers may be sounding alarms. So, are you ready to start paying attention? Here, the things all women need to know now.

1. High cholesterol is surprisingly common.

Researchers with the Framingham Heart Study recently delivered a nasty surprise: Nearly a quarter of women in the study who are in their early 30s have borderline-high levels of bad cholesterol, as do more than a third in their early 40s and more than half in their early 50s. A third of women in all three age groups have low levels of good cholesterol.

Bad cholesterol, also known as low-density lipoprotein, or LDL, contributes to heart disease by laying down artery-clogging plaque; good cholesterol, or high-density lipoprotein (HDL), helps clear it away. "The double whammy of high LDL and low HDL is particularly dangerous," says Framingham researcher Vasan Ramachandran, M.D., of the Boston University School of Medicine.

2. Your doctor may miss the problem.

Though women are better than men about seeing a doctor regularly, the care they receive isn't as good when it comes to preventing and treating cardiovascular disease, according to new studies. "Perhaps doctors still haven't gotten the message that women need to control cholesterol," says Chloe Bird, Ph.D., author of one of these studies and a senior sociologist at the nonprofit RAND Corporation. Bird found that doctors are less likely to monitor and control cholesterol in women than in men, even when the women are at super-high risk of heart attack.

Part of the problem, she says, may be that many women see only a gynecologist. This isn't to say that OB-GYNs can't be good primary care doctors, but you have to make sure the doc is willing to monitor your heart health, especially if you already have diabetes or a heart issue. That means she should order cholesterol checks as part of your regular blood work and discuss the results with you. What does "regular" mean?

3. Your numbers may trick you.

Many people misunderstand the roles of so-called good and bad cholesterols, according to cardiologist and lipidologist Pamela Morris, M.D., of the Medical University of South Carolina in Charleston. "What we've learned is that HDL and LDL are independent predictors of a woman's heart attack risk," she explains. "We see women with high HDLs having heart attacks when their LDL is also high, and we also see heart attacks in women with very low LDL but also low HDL."

What that means to you: It's important to keep track of both. A woman wants to keep her HDL above 60 (the level at which HDL helps prevent disease) and her LDL below 100. If your HDL drops below 50 or LDL rises above 160, you need to take immediate action. That may include an LDL-lowering drug such as a statin, and it definitely includes a commitment to a heart-healthy diet and lifestyle.

4. You may need an "inflammation" test.

The math used to estimate your heart disease risk is a little misleading. If your LDL rises above the danger line of 160 or your HDL drops below 50, the math says you have an elevated risk of a heart attack within 10 years. But that warning may actually underestimate your risks beyond 10 years, Morris says. So when she has a female patient with cholesterol numbers in the intermediate range - LDL above 130 or HDL under 60 - she often takes a close look at the woman's whole-body inflammation level.

You can't see this kind of inflammation, but it's actually an independent measure of heart attack risk. You measure it by adding a test for high-sensitivity C-reactive protein (hs-CRP) to the usual cholesterol blood work. CRP, essentially a body chemical, usually rises anytime your body becomes inflamed. And since artery clogging is associated with inflammation, high CRP is viewed as a marker for clogged arteries. That means your C-reactive protein levels may help you and your doctor decide how aggressively you need to control borderline-high-cholesterol levels with drugs, diet, and exercise.

5. These foods are your best friends.

Certain classes of food chemicals can actively and powerfully lower a person's bad cholesterol. Two - soluble fiber and phytosterols - have so much science behind them that they've become part of standard medical prescriptions for treating high cholesterol. But dietitian Janet Brill, Ph.D., R.D., author of "Cholesterol Down," also recommends regularly eating almonds, ground flaxseed, apples, soy protein, and olive oil. Preliminary research suggests they all have cholesterol-lowering powers. "Each one works in a slightly different way," Brill says. "So together, you get a synergy that can dramatically lower cholesterol."

Almonds and olive oil are high in monounsaturated fats, which are thought to blend with LDL molecules in a way that speeds LDL's clearance from the blood by the liver. Flax is high in both soluble fiber, which lowers LDL by absorbing cholesterol from both food and bile inside the intestines, and omega-3 fatty acids, which studies show have anti-inflammatory effects. Other foods especially high in soluble fiber include oat bran, oatmeal, and apples. (Soluble fiber is different from insoluble fiber, the kind found in whole-grain bread and bran cereal. That's good for you, too, but it won't affect your cholesterol.) Soy may mimic natural estrogens in their LDL-clearing effects. Phytosterols are the plant version of animal sterols (a.k.a. cholesterol) and lower LDL by competing with it for absorption into the body. They're found in supplements or phytosterol-enhanced margarine such as Benecol.

You don't need any of these foods if your LDL is low, but experts still recommend them for everyone. What about steak, eggs, and cheese? They sure won't help your cholesterol, because they all contain a lot of it. But it's more important to focus on foods that lower your numbers rather than simply avoiding the bad stuff, experts say.

6. Good cholesterol may have a bad side.

The higher your HDL, the better, right? That's been the current thinking, due to HDL's protective effect. But here's a surprise you may have read about in some news reports: Studies are showing that HDL may actually have harmful proteins capable of boosting heart disease risks. A test to determine whether your HDL has the harmful proteins may be available in a few years. In the meantime, if your HDL is lower than 60, it's still OK to raise it a little as long as you don't go overboard. How? Try getting a lot of omega-3s from fish or fish oil, exercising regularly, controlling your weight, and avoiding smoking.

7. Your heart loves long walks.

Walking 10 miles a week brings lasting improvements in your heart health, according to researchers at Duke University Medical Center. The funny thing is, if you jog those 10 miles, you won't get quite as much benefit. "Duration appears to be key," says Duke's Cris Slentz, Ph.D., an exercise physiologist. "Jogging or walking 10 miles both burned around 1,200 calories, but in our studies, one took about two hours and the other, three."

Longer stints of exercise, even moderate exercise, may burn more belly fat - the little rolls of skin near your navel and the fat deep inside your abdomen. The latter is linked to metabolic syndrome, a condition associated with a host of cardiovascular risk factors including low HDL, high blood pressure, and high triglycerides (a kind of blood fat that contributes to heart disease).

Should you aim for weight loss as well as long walks? If you're overweight, absolutely. But understand that shedding a few pounds will make only a small dent in your cholesterol. Canadian researchers recently found that overweight women who lost about 25 pounds - no easy task - saw their LDL drop about 10 percent and their HDL rise by the same amount.

Source: cnn.com

See also: Top 10 Tips for a Healthy Heart

Can Yogurt Really Boost Your Health?

One of the hottest food marketing trends these days involves adding live bacteria to dairy products as a way to boost health.
A lawsuit challenges the health claims of Activia,a probiotic yogurt.Dannon claims Activia can help regulate your digestive system.

Now lawyers have filed a class-action lawsuit against yogurt maker Dannon, one of the biggest sellers of “probiotic” yogurts, saying the claims of a health benefit dupe consumers. The company’s Activia and DanActive line of yogurt products contain live bacteria and claim to help regulate digestion and boost the immune system. The suit, filed in United States District Court in California, seeks redress for consumers who purchased the yogurt products based on what it says are “bogus claims.'’

“Deceptive advertising has enabled Dannon to sell hundreds of millions of dollars worth of ordinary yogurt at inflated prices to responsible, health- conscious consumers,” said Los Angeles attorney Timothy G. Blood, of the firm Coughlin Stoia Geller Rudman & Robbins.

In response, Dannon issued a statement saying it “stands by the claims of its products and the clinical studies which support them.'’

“All of Dannon’s claims for Activia and DanActive are completely supported by peer-reviewed science and are in accordance with all laws and regulations,'’ said the statement. “Dannon’s advertising has always been and will continue to be absolutely truthful, and Dannon will vigorously challenge this lawsuit.”

Probiotics are defined as live microorganisms that, in sufficient amounts, confer a health benefit on the host. A growing body of research links probiotics to relief of digestive tract complaints such as irritable bowel syndrome, yeast infections, and diarrhea that results from certain illnesses. The idea behind probiotics is to increase the amount of beneficial bacteria in people’s intestinal tracts as a way to aid digestion, boost the body’s natural defenses and fight off harmful bacteria that can cause health problems.

Although the scientific evidence shows that probiotics really can help, questions remain about how well that research translates into the real world, where some marketers may add untested amounts of the bacteria to various foods. While there are thousands of different probiotics, only a handful have been tested in clinical trials and been shown to deliver specific health benefits when eaten regularly. Most probiotic products can be found in the dairy case or as dietary supplements.

Dannon’s Activia line has been a marketing success story for the company, surpassing $100 million in sales in the United States its first year. The yogurt includes a form of Bifidobacteria that survives passage through the digestive tract, arriving in the colon as a living culture. The company claims that “once there, it plays a beneficial role in your intestinal ecosystem.'’ The yogurts are backed by a high-profile advertising campaign as well as a Web site. The site includes a link to company-sponsored studies showing that the bacteria used in Activia significantly improves regularity in study subjects.

The firm’s DanActive line, meanwhile, contains a different type of bacteria the company claims “helps strengthen your body’s defense.'’

The Food and Drug Administration doesn’t do much to guide consumers on the issue, simply policing food packages to make sure that companies do not try to equate probiotic products with disease-curing drugs.

A 2006 report from the American Society for Microbiology noted that “at present, the quality of probiotics available to consumers in food products around the world is unreliable.”

Source: well.blogs.nytimes.com

US Company Claims Cloned Humans, Made Stem Cells

A California company said on Thursday it used cloning technology to make five human embryos, with the eventual hope of making matched stem cells for patients. Stemagen Corp. in La Jolla, California, destroyed the embryos while testing to make sure they were true clones. But the researchers, based at a fertility center, said they believed their ready source of new human eggs would make their venture a success.

Other experts were skeptical about the claims, published in the journal Stem Cells. If verified, the team would be the first to prove they have cloned human beings as a source of stem cells, the master cells of the body.

There are several types of stem cells. Embryonic stem cells, made from days-old embryos, are considered the most powerful because they can give rise to all the cell types in the body.

The Stemagen team said they got five human embryos using skin cells from two adult men who work at the IVF center. They said they had painstakingly verified that the embryos were clones of the two men.

"We hope it is a bit of a turning point for many more studies," Andrew French, who led the research, said in a telephone interview.

They used a technique called somatic cell nuclear transfer, or SCNT, which involves hollowing out an egg cell and injecting the nucleus of a cell from the donor to be copied -- in this case, the skin cells from the men. It is the same technique used to make Dolly the sheep in 1996, the first mammal to be cloned from an adult. Researchers hope to use the technique to create tailor-made transplants of cells, tissue or organs for patients, treating injuries and diseases like juvenile diabetes.

"Since a significant percentage of couples undergoing fertility treatments appear willing to participate in this type of research, we believe the method described to obtain donated oocytes is a viable and ethically acceptable strategy," the researchers wrote.

MOST SUCCESSFUL SO FAR

Some cloning experts said the work appeared to be genuine.

"This is the most successful description so far of the use of the cloning techniques with purely human material. However, it is still a long way from achieving the goal of obtaining embryonic stem cells," said Robin Lovell-Badge of Britain's Medical Research Council's division of stem cell biology.

"I hope that the authors have the opportunity to continue their work and derive embryo stem cell lines," Ian Wilmut, who led the team that cloned Dolly and who is now at the University of Edinburgh, said in an e-mail.

The field is controversial for several reasons.

President George W. Bush opposes the use of human embryos to make stem cells and has vetoed bills from Congress that would expand federal funding of this research.

South Korean scientist Hwang Woo-suk made headlines when he was found to have faked key parts of a report that his team had used cloning technology to make human embryos in 2004.

"We need to be ultra-cautious after the Hwang scandal and not make the same mistake all over again," said Dr. Robert Lanza of Advanced Cell Technology, a Massachusetts company that is also trying to make human embryonic stem cells. "I'd really like to believe it, but I'm not sold yet," Lanza said.

Other teams have made stem cells they believe are similar to embryonic cells using a variety of techniques, including reprogramming a human egg cell alone, reprogramming ordinary skin cells into what are called induced pluripotent stem cells, or by taking one cell from a human embryo without harming the embryo.

But most stem cell experts agree it is important to continue trying to make stem cells from embryos too.

Source: www.reuters.com

Seawater Seems to Beat Medicine in Fighting Colds

There is no cure for the common cold, but researchers might have found a safe and simple way to reduce a child’s symptoms and the chance of recurrence: wash out the nose with seawater.

In a study published Monday in The Archives of Otolaryngology: Head and Neck Surgery, scientists assigned 289 cold or flu patients ages 6 to 10 to be given a nasal wash three times a day with water from the Atlantic Ocean that had been commercially processed but retained seawater’s trace elements and minerals.

As comparison, a group of 101 children used ordinary over-the-counter cough and cold medicines. Their symptoms were tracked over three months.

Patients on the saline treatment used fewer over-the-counter medicines, had fewer breathing problems and other cold symptoms, and reported fewer illnesses and school absences. The differences were statistically highly significant.

The authors acknowledge that the study was not blind and that the results depended in part on self-reporting by patients. The work was financed by Goemar Laboratoires, a French manufacturer of a saline solution based on seawater.

“It makes sense to clean the cavity where the microbes that might worsen the infection are present,” said Dr. Jana Skoupa', a co-author of the study, who works for a company that provides information to the pharmaceutical industry. “That’s what the seawater does, and it’s the minerals and trace elements in the seawater that help to restore the mucus lining of the nose.”

Source: www.nytimes.com

Quick Guide to Syphilis

8 Facts About Syphilis Everyone Should Know

New genetic evidence supports the theory that Christopher Columbus and his crew brought syphilis to Europe on the way back from their 1492 exploration of the Americas.

Following are facts about syphilis:

• Syphilis is a sexually transmitted disease caused by the the Treponema pallidum bacterium. Because its symptoms mimic those of other diseases, it is often called "the great imitator."
• Syphilis starts out with a painless sore at the site of infection, which often disappears without treatment.
• Weeks later, a rash appears that can cover any part of the body, including the palms of the hands and the soles of the feet. This may be accompanied by fever, fatigue and aches and pains. These signs appear and disappear for up to a year.
• In the tertiary stage, the bacteria may spread to internal organs including to the brain, causing numbness, paralysis, deafness and dementia. It may also cause heart trouble, including an inflammation of the aorta or heart valve problems.
• With early diagnosis, syphilis can be easily be treated with antibiotics.
• Before the advent of penicillin in the 1940s, syphilis had been treated in a range of uncomfortable ways, from toxic mercury to a risky practice of infecting victims with malaria in the hope that the fever would kill off the syphilis.
• Deborah Hayden, author of "Pox: Genius, Madness and the Mysteries of Syphilis," estimates that at its peak in the 19th century, syphilis may have infected as much as 15 percent of adults in Europe and North America.
• In a 2001 report, the World Health Organization estimated that there were an estimated 12 million cases of syphilis a year.

Source: www.reuters.com

Researchers Create Beating Heart With New Cells

Researchers at the University of Minnesota seeking new treatments for heart disease have grown a beating rat heart in the lab by using stem cells. VOA's Jessica Berman reports the research reported by the journal Nature Medicine is laying the groundwork for the transplant of what the scientists are calling bio-artificial organs in humans.

Experts say there are an estimated 100 million people around the world whose hearts do not work well enough to pump blood through their bodies. Many heart patients in need of a transplant will die waiting for a new organ to become available. But the researchers say if human hearts can be made from animal organs, they could save lives.

In their experiments, researchers removed the hearts of newborn lab rats and stripped them of their cells in a process called organ decellularization.

Lead researcher Doris Taylor, who heads the University of Minnesota's Center for Cardiovascular Repair, says investigators were left with a white protein matrix shaped like a heart that contained conduits where the blood vessels had been.

Dr. Taylor says these "ghost" hearts, or scaffolds, were re-populated by infusing them with progenitor cells that have a capacity for self-renewal and differentiation much like stem cells.

Within a few days, Dr. Taylor says the rat hearts began to grow cells on the outside.

"And what is really cool is that over time, our heart actually replaces that matrix that we call it," said Doris Taylor. "It is basically the cell saying 'I need something, something to hang on to,' and they build more of it over time. So, over time the human cells would replace that matrix and you would essentially have an equivalent of a human heart."

The new cells were fed nutrients and were prodded with a pacemaker. After four days, investigators noted some contractions in the rat hearts.

She says eight days later the experimental organs began pumping liquid faintly.

"What we were able to show is that we could take a previously dead heart that we removed all the cells from and really reanimate that with new cells," she said. "So, for the first time we have something that looks like a heart, that has the anatomy of a heart that we can actually begin to rebuild a whole tissue rather than just a little piece of tissue in a laboratory dish."

If perfected on larger hearts it could create a potentially unlimited supply of needed organs, and the researchers say use of a patient's own stem cells would ensure that a bio-artificial heart is compatible with his or her immune system.

The next step is to use the procedure on a pig heart to see if it will work in a larger heart.

Dr. Taylor says bio-artificial hearts for humans could be made from pig organs because the hearts are about the same size. Pig valves are already used to replace diseased heart valves in humans.

"The hope is that we have created a tool that will really make people think differently and provide an opportunity to create new options for tissue engineering and for patients who need organs," said Dr. Taylor.

Researchers in Minnesota are working with scientists in other countries to try to create other bio-artificial organs, including lungs, liver, the pancreas, and kidneys.

Source: www.voanews.com

Study Finds Possible Targets for H.I.V. Drugs

Using a new type of genetic screen, researchers at Harvard Medical School have identified 273 proteins that the AIDS virus needs to survive in human cells, opening up new potential targets for drugs.

Their work, published online on Thursday by Science magazine, used RNA interference to screen thousands of protein-making genes; previously, scientists had identified only 36 human proteins that the virus uses to break into cells, hijack their machinery and start reproducing.

“This is just terrific work,” said Dr. Robert C. Gallo, director of the Institute of Human Virology at the University of Maryland and a co-discoverer of the virus. “I think it’s destined to be one of the top papers in this field for the decade.”

Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases and the government’s top AIDS expert, called the Harvard team’s work “elegant science,” but added a caution.

“It remains to be seen if any of these proteins they identified are useful clinically,” Dr. Fauci said. “This is hypothesis-generating, not hypothesis-solving. It creates a lot of work — someone has to go down each of these pathways.”

The lead author on the paper, Dr. Stephen J. Elledge, is a geneticist, and this is his first work on the human immunodeficiency virus, which causes AIDS. His previous work has been on cancer, Dr. Elledge said, trying to figure out how cells sense when their chromosomes are broken, and this paper was a collaborative effort.

“I can’t even grow H.I.V. in my lab,” Dr. Elledge said, so he had to use virus grown by Dr. Judy Lieberman, director of the medical school’s AIDS division and one of the co-authors.

Dr. Elledge’s team used a library of tens of thousands of different short interfering RNAs, bits of genetic code — each of which, when introduced into a cell, knocks out the cell’s ability to make a single protein.

Next, about 21,000 samples of cells, each crippled in its ability to produce one protein, were placed in separate wells on laboratory plates and dosed with the virus.

If the virus could not reproduce normally in a given well, it suggested that the missing protein was one of those it needed.

Of the 273 human proteins identified, only 36 had been previously found by other methods.

The virus, which is itself only a short string of genetic material inside a protective capsule, can make only 15 proteins, so it has to adopt human proteins to its own use.

The advantage of targeting human proteins is that the virus would presumably not be able to mutate to avoid drugs that block them, Dr. Elledge said. Right now, virus strains evolve resistance to antiretroviral drugs, which attack the 15 proteins made by the virus itself, like reverse transcriptase and protease. The mutations force AIDS patients to switch drug regimens — not always successfully.

The disadvantage is that blocking human proteins can, obviously, be fatal to humans. But, as Dr. Gallo pointed out, cancer therapy works that way — doctors try to block proteins that feed fast-growing tumor cells without killing too many other fast-growing cells, like those in the bone marrow.

Right now, Dr. Elledge said, only one drug that targets one of the known human proteins, a receptor called CCR5, has been developed, and it has just won approval.

The new screening technology, known as siRNA, is now used in many laboratories, so this work could theoretically have been done elsewhere, or by using older, more laborious methods.

Dr. Elledge said he benefited from working at Harvard, which could afford the expensive robotics and imaging technology needed.

“And I had lots of collaborators and very dedicated people,” he said.

To confirm that the newly identified proteins were important to the life cycle of the virus — which Dr. Elledge described as “opaque” — the team ran further tests on three of them.

Many of the proteins identified by the screen are already known to be important to cells in the immune system, which is the port of entry for H.I.V.

Dr. Abraham L. Brass, a co-author, said the screening method undoubtedly missed other proteins the virus needs, “but the majority of the ones we found are highly likely to play a role in H.I.V. propagation.”

Source: www.nytimes.com

Sweetener in Chewing Gum Can Damage Your Health

A sweetener used in sugar-free chewing gum, some toothpastes and thousands of other products could be a severe health risk, doctors warned.

Sorbitol, also known as E 420, can trigger severe weight loss, abdominal pain and diarrhoea.

A report in the British Medical Journal today highlights the cases of patients who lost up to a fifth of their bodyweight.

The cause was eventually traced to excess intake of sorbitol - one was eating 14-20 sticks of gum a day.

Dentists recommend chewing sugarfree gum to increase saliva production, which reduces cavities and strengthens teeth.

Wrigley, which owns many of the brands sold in the UK, has seen its sales in Europe grow by a third since Sorbitol is also used in sugar-free sweets, some cereals and foods aimed at diabetics.

But gastroenterology experts in Germany say many consumers - and even some doctors - are unaware of the laxative side-effects of sorbitol, which can also hinder the absorption of nutrients into the small intestine.

Professor Herbert Lochs and Dr Juergen Bauditz, from the University of Berlin studied two patients with chronic diarrhoea, abdominal pain and substantial weight loss.

They underwent extensive investigation before a detailed analysis of their eating was undertaken. It found both had been consuming large amounts of sugarfree gum and sweets.

The first, a 21-year-old woman, chewed around 15 sticks of gum a day. Her weight plunged by almost 2st to just 6st 6lb.

The second patient, a 46-year-old man, chewed 20 sticks of gum and ate up to 200g of sweets each day. He lost more than 3st in a year.

After they started a sorbitol-free diet, their diarrhoea stopped and they gained weight.

Professor Lochs said the cases were unusual because the consumption of sorbitol was not enormously high yet the effects had been serious. He said the public, particularly diabetics who buy low- sugar or sugar-free foods, should be warned that too much sorbitol may be "dangerous".

The professor said warnings about possible side-effects were usually "in the small print" of packaging and people who suffered gastrointestinal problems might not make the connection. Doctors also needed to be alert to the possibility.

Professor Lochs said men and women should not try to lose weight using sugarfree gum because their intake of nutrients would be affected..

Wrigley said last night: "It is well documented in medical literature, with studies going back more than 20 years, that excessive consumption of polyols such as sorbitol can have a laxative effect in some individuals.

"Those studies generally indicate that people can consume up to 40g of sorbitol without experiencing a laxative effect - subject to the individual and other diet components - a level not even approached by normal consumption of sugar-free chewing gum."

The company said its labelling carried warnings required by EU regulations.

Jemma Edwards, Care Advisor and registered dietician at Diabetes UK, said "We already know that many sweeteners have a laxative effect.

"Diabetes UK does not recommend 'diabetic' food because there are no added nutritional benefits and it is often more expensive. People with diabetes can eat normal food as long as they have a healthy, balanced diet."

Source: www.dailymail.co.uk