Few Twitter users spreading most fake news: Study

New York, May 19: Cigarette smoke spurs the lungs to make more of the receptor protein which the novel coronavirus uses to enter human cells, according to a study which suggests that quitting smoking might reduce the risk of a severe coronavirus infection.

The findings, published in the journal Developmental Cell, may explain why smokers appear to be particularly vulnerable to severe COVID-19 disease.

"Our results provide a clue as to why smokers who develop COVID-19 tend to have poor clinical outcomes," said study senior author Jason Sheltzer, a cancer geneticist at Cold Spring Harbor Laboratory in the US.

"We found that smoking caused a significant increase in the expression of ACE2, the protein that SARS-CoV-2 uses to enter human cells," Sheltzer said.

According to the scientists, quitting smoking might reduce the risk of a severe coronavirus infection.

They said most individuals infected with the virus suffer only mild illness, if they experience any at all.

However, some require intensive care when the sometimes-fatal virus attacks, the researchers said.

In particular, they said three groups have been significantly more likely than others to develop severe illness -- men, the elderly, and smokers.

Turning to previously published data for possible explanations for these disparities, the scientists assessed if vulnerable groups share some key features related to the human proteins that the coronavirus relies on for infection.

First, they said, they focused on comparing gene activity in the lungs across different ages, between the sexes, and between smokers and nonsmokers.

The scientists said both mice that had been exposed to smoke in a laboratory, and humans who were current smokers had significant upregulation of ACE2.

According to Sheltzer, smokers produced 30-55 per cent more ACE2 than their non-smoking counterparts.

While the researchers found no evidence that age or sex impacts ACE2 levels in the lungs, they said the influence of smoke exposure was surprisingly strong.

However, they said, the change seemed to be temporary.

According to the data, the level of the receptors ACE2 in the lungs of people who had quit smoking was similar to that of non-smokers.

The study noted that the most prolific producers of ACE2 in the airways are mucus-producing cells called goblet cells.

Smoking is known to increase the prevalence of such cells, the scientists said.

"Goblet cells produce mucous to protect the respiratory tract from inhaled irritants. Thus, the increased expression of ACE2 in smokers' lungs could be a byproduct of smoking-induced secretory cell hyperplasia," Sheltzer explained.

However, Sheltzer said other studies on the effects of cigarette smoke have shown mixed results.

"Cigarette smoke contains hundreds of different chemicals. It's possible that certain ingredients like nicotine have a different effect than whole smoke does," he said.

The researchers cautioned that the actual ACE2 protein may be regulated in ways not addressed in the current study.

"One could imagine that having more cells that express ACE2 could make it easier for SARS-CoV-2 to spread in someone's lungs, but there is still a lot more we need to explore," Sheltzer said.

Washington D.C., Jan 12: Disruption in one night's sleep can lead to getting Alzheimer's disease, a recent study has stated.

The interruption in the sound sleep for a single night aggravates the level of tau protein in any young male's body, thus gives rise to the chances of developing the disease.

According to CNN, the report was published on Wednesday in neurology, the medical journal of the American Academy of Neurology.

"Our study focuses on the fact that even in young, healthy individuals, missing one night of sleep increases the level of tau in blood suggesting that over time, such sleep deprivation could possibly have detrimental effects," says study author Dr Jonathan Cedernaes, a neurologist at Uppsala University in Sweden.

As defined by the Alzheimer's Association, tau is the name of a protein that helps in stabilizing the internal structure of the brain's nerve cells. An abnormal build-up of tau protein in the body can end up in causing interior cells to fall apart and eventually developing Alzheimer's.

"When you get more of that deep sleep and you get the REM sleep in the normal amounts, that improves clearance of abnormal proteins which we think is good," said Mayo Clinic neurologist Dr Donn Dexter, not the study author but a fellow of the American Academy of Neurology.

Earlier studies have also shown that getting deprived of sleep can allow higher tau development and accumulation. Thus that poor sleep can hasten the development of cognitive issues.

Researchers caution that the study is small and inconclusive, and acknowledged they were not able to determine what the increased levels might mean.

"This study raises more questions than answers," agreed Dexter on a concluding note, sharing, "What this is telling us is that we have to dig more deeply. Despite something we do for a third of our lives, we know so little about sleep and we're learning every day, particularly when it comes to sleep and dementia."

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.