Researchers have developed a new approach to rapidly expand the number of human liver cells in the laboratory without losing their unique metabolic function.

"This is the holy grail of liver research," said the study's lead author Yaakov Nahmias from Hebrew University of Jerusalem in Israel.

The research could help advance a variety of liver-related research and applications, from studying drug toxicity to creating bio-artificial liver support for patients awaiting transplantations.

"Our technology will enable thousands of laboratories to study fatty liver disease, viral hepatitis, drug toxicity and liver cancer at a fraction of the current cost," Nahmias noted.

Thus far, attempts to expand human hepatocytes - cells that comprise 85 percent of the liver - in the laboratory resulted in immortalised cancer cells with little metabolic function.

The scarce supply of human hepatocytes and this inability to expand them without losing function is a major bottleneck for scientific, clinical and pharmaceutical development.

The new method, described as the "upcyte process," allows expanding human hepatocytes, resulting in a quadrillion cells from each liver isolation, compared to only a billion cells that can be isolated from a healthy organ.

"The approach is revolutionary," said Joris Braspenning from Germany-based biotechnoloy company Upcyte Technologies.

"Its strength lies in our ability to generate liver cells from multiple donors, enabling the study of patient-to-patient variability and idiosyncratic toxicity," Braspenning said.

The study appeared in the journal Nature Biotechnology.

Certain food odours activate the impulse area of the brain in obese children, researchers report, adding that obesity can have a neurological link.

In order to fight obesity, it is crucial to understand the brain mechanisms of odour stimulus.

"This study has given us a better understanding that obesity has a neurological disorder component. The findings have the potential to affect treatment of obese patients," said Pilar Dies-Suarez, chief radiologist at Hospital Infantil de Mexico Federico Gomez.

The team studied 30 children between the ages of six and 10 years old.

Half of the children had a normal body mass index (BMI) between 19 and 24, and the other half exhibited a BMI over 30 which is classified as obese.

Each child was presented with three odour samples: chocolate, onion and a neutral odour of diluted acetone.

The results showed that in the obese children, the food odours triggered activation in the areas of the brain associated with impulse and the development of obsessive-compulsive disorder while the areas associated with impulse control exhibited no activity.

The chocolate smell elicited significant brain connections in obese children, compared to the normal-weight children.

"However, in the children with a normal BMI, the areas of the brain associated with pleasure regulation, organisation and planning, as well as regions governing emotional processing or memory function, became more active," the authors noted.

"If we are able to identify the mechanisms that cause obesity, we will be able to change the way we treat these patients, and in turn, reduce obesity prevalence and save lives," Dr Dies-Suarez concluded.

The findings will be shared at the annual meeting of the Radiological Society of North America (RSNA) next month.

Walking a little faster or for a few extra blocks may be good for older adults' hearts, according to a new study.

In the large prospective community-based study of older Americans, modest physical activity was associated with a lower risk of cardiovascular disease (CVD). This was true even among men and women older than age 75 at baseline - a rapidly growing population for whom regular activity has been advised, but with little supportive empirical evidence.

Led by senior author Dariush Mozaffarian, the Tufts University researchers found that after adjustment for other risk factors and lifestyle behaviors, those who were more active had significantly lower risk of future heart attacks and stroke.

Adults who walked at a pace faster than three miles per hour (mph) had a 50 percent, 53percent, 50percent lower risk of coronary heart disease (CHD), stroke and total CVD, respectively, compared to those who walked at a pace of less than two mph.

Those who walked an average of seven blocks per day or more had a 36percent, 54percent and 47percent lower risk of CHD, stroke and total CVD, respectively, compared to those who walked up to five blocks per week.

Those who engaged in leisure activities such as lawn-mowing, raking, gardening, swimming, biking and hiking, also had a lower risk of CHD, stroke and total CVD, compared to those who did not engage in leisure-time activities.

The findings were similar in both men and women, in those above or below age 75 at baseline, and including only those with similarly good or excellent self-reported health.

Mozaffarian noted that these results are especially relevant because, with advancing age, the ability to perform vigorous types of activity often decreases. These support the importance of continuing light to moderate exercise to improve health across the lifespan.

The study appears in Circulation.

If you work in shifts, you are more prone to heart ailments and diabetes as compared to people who work in regular daytime shifts, says a new study.

Researchers have long recognised that shift work can contribute to metabolic risk because of the continual disruption to the circadian system.

Shift workers are more likely to develop metabolic syndrome, coronary heart disease and Type 2 diabetes than employees with regular daytime shifts, researchers said.

Sleep disruption is among the factors that have contributed to rising rates of diabetes and obesity.

"Social jetlag refers to the mismatch between an individual's biological circadian rhythm and their socially imposed sleep schedules. Other researchers have found that social jetlag relates to obesity and some indicators of cardiovascular function," said Patricia M. Wong from the University of Pittsburgh.

"However, we found that even among healthy adults who experience a less extreme range of mismatches in their sleep schedule, social jetlag can contribute to metabolic problems.

"These metabolic changes can contribute to the development of obesity, diabetes and cardiovascular disease," Wong added.

Researchers examined sleep patterns and cardiometabolic risk in a group of 447 men and women who were between the ages of 30 and 54.

Among the participants, nearly 85 percent had a later halfway point in their sleep cycle - a measurement known as midsleep - on free days compared to work days.

The other 15 percent had an earlier midsleep on free days than on work days.

Participants who had a greater misalignment between their sleep schedules on free and work days tended to have poorer cholesterol profiles, higher fasting insulin levels, larger waist circumference, higher body-mass index and were more resistant to insulin than those who had less social jetlag.

The study was published in the Journal of Clinical Endocrinology amd Metabolism.

Overweight men are just as likely as overweight women to experience subtle forms of discrimination when applying for a job or shopping at retail stores, says new research.

"We were interested in looking at biases toward men who are heavy in employment settings," said one of the researchers Enrica Ruggs from University of North Carolina, Charlotte (UNCC) in the US.

"A lot of the research that has looked at weight stigmatization or discrimination toward heavy people has tended to focus on women. It's perceived as more of a critical issue surrounding women, so we wanted to see if men experience some of the same types of detriments that women face," Ruggs noted.

The research involved two studies. In the first study, non-overweight men applied for jobs at retail stores and the same men applied at different stores wearing overweight prosthetics.

The researchers also wanted to investigate if overweight men would be subjected to discrimination as customers, so the same men posed as customers and visited other retail stores.

They found that when the men applied for jobs or were shopping as customers in their overweight prosthetics, they experienced more types of subtle discrimination, or what the researchers call "interpersonal discrimination".

"Employees they interacted with would try to end the interaction early, there was less affirmative behaviour like less nodding or smiling; there was more avoidance types of behaviour like frowning and trying to get out of the interaction," Ruggs said.

The findings suggest that men who are heavy are experiencing really negative behaviours more often than men who are not heavy.

The researchers also looked into the situation where male retail employee was overweight.

This study too found the same types of subtle discrimination was taking place, this time with the customer being the discriminator.

The researchers found, customers thought, the overweight representatives were less professional, their appearance was less neat and clean and they were more careless.

The study was published in the journal of Applied Psychology.