Scientists have discovered that a set of proteins that are a part of the body`s natural defences cause mutations in human DNA, which could potentially lead to cancer, says a study.

According to a study led by researchers at the National Institutes of Health, these naturally occurring mutations are just as powerful as known cancer-causing agents in producing tumours, reports Science Daily.

The proteins are part of a group called apolipoprotein B mRNA like (APOBEC) cytidine deaminases. The investigators found that APOBEC mutations can outnumber all other mutations in some cancers, accounting for over two-thirds in some bladder, cervical, breast, head and neck, and lung tumours.

The scientists published their findings online July 14 in the journal Nature Genetics. Dmitry Gordenin, Ph.D., is corresponding author of the paper and a senior associate scientist at the National Institute of Environmental Health Sciences (NIEHS), part of NIH.

He said scientists knew the main functions of APOBEC cytosine deaminases were to inactivate viruses that attack the body and prevent ancient viruses present in the human genome from moving around and causing disrupting mutations.

Because they are so important to normal physiology, he and his collaborators were surprised to find a dark side to them; that of mutating human chromosomal DNA.

Obesity has reached epidemic proportions worldwide, with around 2.8 million people dying each year as a result of being overweight or obese, according to international health experts.

Globalisation has brought fast food culture to Chinese cities, contributing to major obesity problems. A study in 2006 found that over one-fifth of the one billion obese or overweight people in the world are Chinese, Xinhua reported.

One of the fattest nations in the developed world, Australia also shares this obesity problem. If Australians` weight gain continues at current levels, almost 80 percent of adults will be overweight or obese by 2025, according to Monash University.

To discuss the problem of obesity and evaluate a solution being developed by the Public Health Association of Australia, international nutrition experts met at an obesity and nutrition conference in Sydney.

The rise of multinational fast food outlets has been a key change in our environment leading to fatter foods and fatter people, said Bruce Neal, professor at the George Institute for Global Health in Sydney.

"As fast as we get rid of all our traditional vectors of disease -- infections, little microbes, bugs -- we are replacing them with the new vectors of disease, which are massive transnational, national, multinational corporations selling vast amounts of salt, fat and sugar," Neal said.
Over time, consumers in developed countries have become acculturated to larger serving sizes that are well above what`s necessary for an enjoyable, sensible and nutritious meal, said Tim Gill, associate professor at the University of Sydney`s Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders.

"People will consume a portion that`s put in front of them. People will seek value by purchasing the largest portion size, because it`s relatively cheap compared to the smaller size. We`ve just had a disconnect in terms of what we need to eat and what we can purchase," he said.

A 2005 study by American scientists found that diners who ate from a bowl of soup that kept refilling would not only eat far more than normal, but they did not notice that they had eaten more, and did not feel more sated.

Most shoppers base their food choices on price rather than nutritional value, with lower socio-economic status consumers more likely to eat high energy-dense foods such as sugary drinks, said Marion Hetherington, a professor of biopsychology at the University of Leeds.

However, Jennie Brand-Miller, a professor at the University of Sydney`s School of Molecular Bioscience, said low-fat diets may not in fact be best for our health.

"Low-fat dietary advice has not been helpful on a population level. It is consistently associated with weight regain. It does not reduce the risk of chronic disease," said Brand-Miller.

"We need to pay more importance to protein. Protein is satiating, and we`ve undervalued it. We need to pay more attention to the sources of carbohydrate -- we need to switch from high GI to low GI carbohydrates," she said.

At the heart of the obesity issue is the question of responsibility, and whether it`s up to the consumers to look after their own needs, or industry to provide more healthy foods.

"In Britain, the public health responsibility has been an important initiative in the sense that companies will sign up, they will pledge to reduce the amount of calories in their food, to reduce the amount of salt," said Hetherington.

By lowering salt, sugar and calorie content of their foods independently, industry will not face competitive pressure caused by only some producers providing more healthy foods in the marketplace, she said.

Stanford researchers are on track to begin human trials of a potentially potent new drug against cancer by next year, it has been revealed.

The progress comes just two months after the groundbreaking study by Dr Irv Weissman, who developed an antibody that breaks down a cancer`s defense mechanisms in the body, the New York Post reported.

A protein called CD47 tells the body not to "eat" the cancer, but the antibody developed by Dr Weissman blocks CD47 and frees up immune cells called macrophages - which can then engulf the deadly cells.

The new research shows the miraculous macrophages effectively act as intelligence gatherers for the body, pointing out cancerous cells to cancer-fighting "killer T" cells.

The T cells then "learn" to hunt down and attack the cancer, the researchers claimed.

The clinical implications of the process could be profound in the war on cancer.

When macrophages present "killer T" cells with a patient`s cancer, the T cells become attuned to the unique molecular markers on the cancer.

This turns them into a personalized cancer vaccine.

The team of researchers at Stanford plan on starting a small 10-100 person phase I clinical human trial of the cancer therapy in 2014.

A new study has found that 4-year-olds with shorter than average sleep times have increased rates of "externalizing" behaviour problems.

"Preschool children with shorter night time sleep duration had higher odds of parent-reported overactivity, anger, aggression, impulsivity, tantrums, and annoying behaviours," according to the new research by Dr. Rebecca J. Scharf of University of Virginia, Charlottesville, and colleagues.

They recommend that parents and health care providers discuss steps to improve sleep habits for preschool-age children with behaviour problems.

The researchers analyzed parent responses from a nationally representative study of approximately 9,000 children, followed from birth through kindergarten age.

When the children were four years old, night time sleep duration was estimated by asking the parents what time their child typically went to bed and woke on weekdays.

On a standard child behaviour questionnaire, parents rated their child on six different "externalizing" behaviour problems such as anger and aggression. (Externalizing behaviour problems are outward behaviours, distinguished from "internalizing" problems such as depression and anxiety.)

The relationship between sleep duration and behaviour scores was assessed, with adjustment for other factors that might affect sleep or behaviour.

The average bedtime was 8:39 pm and wake time 7:13 am, giving a mean night time sleep duration of about 10 and a half hours. Eleven percent of children were considered to have "short sleep duration" of less than 9 hours 45 minutes (calculated as one standard deviation below the average).

On the child behaviour questionnaire, 16 percent of children had a high score for externalizing behaviour problems.

Behaviour problems were more common for boys, children who watched more than two hours of television daily, and those whose mothers reported feeling depressed.

After adjustment for other factors, "Children in the shortest sleep groups have significantly worse behaviour than children with longer sleep duration," Dr Scharf and colleagues write.

The effect was greatest for aggressive behaviour problems, which were about 80 percent more likely for children with night time sleep duration of less than 9 hours and 45 minutes.

The study is published in the Journal of Developmental and Behavioral Pediatrics, the official journal of the Society for Developmental and Behavioral Pediatrics.

Despite public health campaigns, smoking remains the leading avoidable cause of death worldwide, killing almost six million people a year, mostly in low- and middle-income countries, the World Health Organization has said.

If current trends hold, the number of deaths blamed on tobacco use will rise to eight million a year in 2030, the WHO said yesterday in a briefing unveiled at a conference in Panama.

About 80 percent of tobacco-related deaths forecast for 2030 are expected in low- and middle-income countries, the report added.

"If we do not close ranks and ban tobacco advertising, promotion and sponsorship, adolescents and young adults will continue to be lured into tobacco consumption by an ever-more aggressive tobacco industry," said WHO Director-General Dr Margaret Chan.

"Every country has the responsibility to protect its population from tobacco-related illness, disability and death."

Among the dead this year, five million were tobacco users or former users, while more than 600,000 died from second-hand smoke, according to the WHO.

Tobacco use is believed to have caused the deaths of 100 million people in the 20th century.

Barring dramatic change, the tally for this century could soar to one billion people, the WHO warned.

"We know that only complete bans on tobacco advertising, promotion and sponsorship are effective," Dr Douglas Bettcher, the Director of the WHO`s Prevention of Noncommunicable Diseases department, told the Panama conference.

"Countries that introduced complete bans together with other tobacco control measures have been able to cut tobacco use significantly within only a few years," he said.

The report noted that 2.3 billion people from 92 countries benefit from some form of smoking restrictions, more than double the number who did five years ago.

However, that figure still represents just a third of the world`s population, it said.