E-cigarettes can damage DNA, up cancer risk

Singapore, May 25: COVID-19 patients are no longer infectious after 11 days of getting sick even though some may still test positive, according to a new study by infectious disease experts in Singapore.

A positive test "does not equate to infectiousness or viable virus," a joint research paper by Singapore's National Centre for Infectious Diseases and the Academy of Medicine, Singapore said. The virus "could not be isolated or cultured after day 11 of illness."

The paper was based on a study of 73 patents in the city-state.

The latest findings may have implications on the country's patient discharge policy. The discharge criteria is currently based on negative test results rather than infectiousness.

Singapore's strategy on managing COVID-19 patients is guided by the latest local and international clinical scientific evidence, and the Ministry of Health will evaluate if the latest evidence can be incorporated into its patient clinical management plan, according to a report by the Straits Times.

So far, 13,882, or about 45% of the total 31,068 Covid-19 patients in Singapore have been discharged from hospitals and community facilities. Singapore reported 642 new Covid-19 cases as of noon on Saturday.

The government has been actively screening pre-school staff as it prepares to reopen pre-schools from June 2. On Friday, two pre-school employees tested positive for the novel coronavirus, bringing the total number of confirmed cases among pre-school staff to seven, according to the Ministry of Health.

Colorado, Jul 24: A new study has found that physical stress in one's job may be associated with faster brain ageing and poorer memory.

Aga Burzynska, an assistant professor in the Department of Human Development and Family Studies, and her research team connected occupational survey responses with brain-imaging data from 99 cognitively normal older adults, age 60 to 79. They found that those who reported high levels of physical stress in their most recent job had smaller volumes in the hippocampus and performed poorer on memory tasks. The hippocampus is the part of the brain that is critical for memory and is affected in both normal ageing and in dementia.

Their findings were published this summer in Frontiers in Human Neuroscience under the research topic 'Work and Brain Health Across the Lifespan.'

"We know that stress can accelerate physical ageing and is the risk factor for many chronic illnesses," Burzynska said. "But this is the first evidence that occupational stress can accelerate brain and cognitive ageing."

She added that it is important to understand how occupational exposures affect the ageing of our brains.

"An average American worker spends more than eight hours at work per weekday, and most people remain in the workforce for over 40 years," Burzynska said. "By pure volume, occupational exposures outweigh the time we spend on leisure social, cognitive and physical activities, which protect our ageing minds and brains."

Physical demands at work

Burzynska explained that the association between "physical stress" and brain/memory were driven by physical demands at work. These included excessive reaching, or lifting boxes onto shelves, not necessarily aerobic activity. This is important because earlier work by Burzynska and her colleagues showed that leisure aerobic exercise is beneficial for brain health and cognition, from children to very old adults. Therefore, the researchers controlled for the effects of leisure physical activity and exercise.

As expected, leisure physical activity was associated with greater hippocampal volume, but the negative association with physical demands at work persisted.

"This finding suggests that physical demands at work may have parallel yet opposing associations with brain health," Burzynska explained. "Most interventions for postponing cognitive decline focus on leisure, not on your job. It's kind of unknown territory, but maybe future research can help us make some tweaks to our work environment for long-term cognitive health."

She added that the results could have important implications for society.

"Caring for people with cognitive impairment is so costly, on economic, emotional and societal levels," Burzynska said. "If we can support brain health earlier, in middle-aged workers, it could have an enormous impact."

The researchers considered and corrected for several other factors that could be related to work environment, memory and hippocampus, such as age, gender, brain size, educational level, job title, years in the occupation and general psychological stress.

One piece of the puzzle

"The research on this topic is so fragmented," Burzynska said. "One previous study linked mid-life managerial experience with greater hippocampus volume in older age. Another showed that taxi drivers had larger hippocampi than a city's bus drivers, presumably due to the need to navigate. In our study, job complexity and psychological stress at work were not related to hippocampal volume and cognition. Clearly, our study is just one piece of the puzzle, and further research is needed."

The magnetic resonance imaging (MRI) data used for the study was collected at the University of Illinois Urbana-Champaign between 2011 and 2014.

CSU researchers now can collect MRI data with the new 3T scanner at the University's Translational Medicine Institute.

With this new capability, Burzynska, along with Michael Thomas and Lorann Stallones of CSU's Department of Psychology, is launching a new project, "Impact of Occupational Exposures and Hazards on Brain and Cognitive Health Among Aging Agricultural Workers," which will involve collecting MRI brain scans and identifying risk and protective factors that could help the agricultural community age successfully. The project recently obtained funding as an Emerging Issues Short-Term Project from the High Plains Intermountain Center for Agricultural Health and Safety.

The Department of Human Development and Family Studies is part of CSU's College of Health and Human Sciences.

Toronto, Jul 10: Pasteurising breast milk at 62.5 degrees Celsius for 30 minutes inactivates the SARS-CoV-2 virus that causes Covid-19, making it safe for consumption by babies, a study claims.

According to the research published in the Canadian Medical Association Journal, current advice for women with Covid-19 is to continue to breastfeed their own infants.

In Canada, it is standard care to provide pasteurised breast milk to very-low-birth-weight babies in hospital until their own mother's milk supply is adequate, the researchers said.

"In the event that a woman who is Covid-19-positive donates human milk that contains SARS-CoV-2, whether by transmission through the mammary gland or by contamination through respiratory droplets, skin, breast pumps and milk containers, this method of pasteurisation renders milk safe for consumption," said Sharon Unger, a professor at the University of Toronto in Canada.

The Holder method, a technique used to pasteurise milk in all Canadian milk banks at 62.5 degrees Celsius for 30 minutes, is effective at neutralising viruses such as HIV, hepatitis and others that are known to be transmitted through human milk, the researchers said.

In the latest study, the researchers spiked human breast milk with a viral load of SARS-CoV-2 and tested samples that either sat at room temperature for 30 minutes or were warmed to 62.5 degrees Celsius for 30 minutes.

They then measured for active virus, finding that the virus in the pasteurised milk was inactivated after heating.

More than 650 human breast milk banks around the world use the Holder method to ensure a safe supply of milk for vulnerable infants, the researchers said.