Gene-editing damages DNA more than thought: study

Agencies
July 17, 2018

Paris, Jul 17:  A revolutionary gene editing technique hailed as the future of disease eradication and mooted for a Nobel Prize may be less precise and cause more cell damage than previously thought, researchers said Monday.

Lab experiments using mouse and human cells revealed that the CRISPR-Cas9 technique "frequently" caused "extensive" gene mutations, a study team reported.

"This is the first systematic assessment of unexpected events resulting from CRISPR-Cas9 editing," said Allan Bradley of the Wellcome Sanger Institute in England, where the team conducts research.

The research showed that "changes in the DNA have been seriously underestimated before now," said Bradley, who co-authored a study published in the journal Nature Biotechnology.

The mutations have not been shown to be harmful, nor benign.

"It is important that anyone thinking of using this technology for gene therapy proceeds with caution and looks very carefully to check for harmful effects," Bradley said in a statement issued by the institute.

First unveiled about six years ago, CRISPR-Cas9 allows scientists to insert, remove and correct a faulty sequence on a strand of DNA in a cell with pinpoint precision.

It has raised hopes that one-day disease-causing genes could be removed or altered before a baby is even born.

In recent years, CRISPR-Cas9 has repeatedly been predicted to win the Nobel Chemistry Prize.

CRISPRs -- clustered regularly interspaced short palindromic repeats -- are part of the immune defence system in bacteria, used to hone in on the exact spot on the genome where the cut should be made.

Cas9 is a protein used as "scissors" to snip through the faulty gene, which is then replaced or fixed by the cell's own DNA repair mechanism.

The technique's safety has not yet been proven, and it is not approved for use in human therapy.

So far, researchers have used it to improve hearing in mice going deaf and to fix a disease-causing mutation in cloned, early-stage human embryos.

But the new finding raises "safety implications," the team said.

They found "large genetic rearrangements such as DNA deletions and insertions" in cells, which could lead to important genes being switched on or off and causing dangerous changes.

The research also showed that standardized tests do not pick up damage to DNA caused by CRISPR-Cas9.

Experts not involved in the study said it was unclear how such large, unintended changes were not noticed before.

But, "the results give no reason to panic or to lose faith in the methods when they are carried out by those who know what they are doing," said Robin Lovell-Badge of The Francis Crick Institute, a biomedical research centre in London.

For Francesca Forzano, a consultant in clinical genetics and genomics with the Guy's and St Thomas' NHS Foundation Trust, the work showed that CRISPR-Cas9 "is much less safe than previously thought" and that safety-monitoring techniques were "not entirely adequate".

More research is needed before any clinical application of the method is considered, said Forzano.

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Agencies
July 5,2020

The deadly coronavirus that entered India while there was still nip in the air has beaten rising mercury, humid conditions, unique Indian genome and has entered monsoon season with more potency as fresh cases are only breaking all records in the country.

India recorded a single-day spike of record 24,850 new coronavirus cases on Sunday, taking its total tally to 6.73 lakh corona-positive cases.

Top Indian microbiologists were hopeful in March that after the 21-day lockdown, as summer approaches, the rise in temperature would play an important role in preventing the drastic spread of COVID-19 virus in India.

Several virologists hinted that by June this year, the impact of COVID-19 would be less than what it appeared in March-April.

The claims have fallen flat as the virus is mutating fast, becoming more potent than ever.

According to experts, the novel coronavirus is a new virus whose seasonality and response to hot humid weather was never fully understood.

"The theory was based on the fact that high temperatures can kill the virus as in sterilisation techniques used in healthcare. But these are controlled environment conditions. There are many other factors besides temperature, humidity which influence the transmission rate among humans," Dr Anu Gupta, Head, Microbiologist and Infection Control, Fortis Escorts Heart Institute, told IANS.

There is no built-up immunity to COVID-19 in humans.

"Also, asymptomatic people might be passing it to many others unknowingly. New viruses tend not to follow the seasonal trend in their first year," Gupta emphasized.

Globally, as several countries are now experiencing hot weather, the World Health Organization (WHO) reported a record hike in the number of coronavirus cases, with the total rising by 2,12,326 in 24 hours in the highest single-day increase since COVID-19 broke out.

So far over 11 million people worldwide have tested positive for the disease which has led to over 5,25,000 deaths, according to data from Johns Hopkins University. The US remained the worst-hit country with over 28 lakh cases, followed by Brazil with 15.8 lakh.

According to Sandeep Nayar, Senior Consultant and HOD, Respiratory Medicine, Allergy & Sleep Disorders, BLK Super Speciality Hospital in New Delhi, whether temperature plays a role in COVID-19 infection is highly debated.

One school of thought said in the tropical regions of South Asia, the virus might not thrive longer.

"On the other hand, another school of thought has found that novel Coronavirus can survive in a hot and humid environment and tropical climate does not make a difference to the virus. According to them, this is what distinguishes the novel coronavirus from other common viruses, which usually wane in hot weather," stressed Nayar.

Not much has been studied in the past and no definite treatment or vaccine is available to date.

"Every day, new properties and manifestation of the disease come up. As of now, the only way to prevent this monster is by taking appropriate precautions. Hand hygiene, social distancing, cough etiquette and face masks definitely reduce spread of COVID-19 infection," Nayar told IANS.

Not just top Indian health experts, even Indian-American scientists had this theory in mind that sunshine and summer may ebb the spread of the coronavirus.

Ravi Godse, Director of Discharge Planning, UPMC Shadyside Pennsylvania in the US told IANS in April: "In the summer, the humidity can go up as well, meaning more water drops in the air. If the air is saturated with water and somebody sneezes virus droplets into such air, it is likely that the droplets will fall to the ground quicker, making them less infectious. So the short answer is yes, summer/sunshine could be bettera.

According to Dr Puneet Khanna, Head of Respiratory Medicine and Pulmonology, Manipal Hospital, Delhi, COVID-19 death rates are not too different in tropical countries but since the disease affected them late it was yet to show its peak in these areas.

"The virus can survive well in hot and humid countries and this is proven now," he stressed.

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Agencies
April 15,2020

Dear parents, if you want your children to have proper sleep, read this carefully. Joining a growing list of studies that tell parents to shun devices at bed-time, researchers say that children who use devices and decide what time they go to sleep, achieve less sleep and feel more sleepier the following day than their peers.

The study of children in this age-group (aged 11 to 13 years), published in the New Zealand Medical Journal, found most (72 per cent) of the 163 students interviewed by University of Otago researchers achieved recommended guidelines of an average 9 to 11 hours sleep nightly over one week.

"But that also means that almost one in four students did not achieve sleep within these guidelines, which highlights an area for improvement," said study researcher Kate Ford.

However, consistent with previous research in 15 to 17-year-old New Zealanders, the study results show less sleep on the nights where devices are used in the hour before bed.

According to the researchers, students who used devices before going to sleep were also more likely to report that they felt sleepy the following morning. Watching television before bed had no significant effect on sleep length.

There were also some interesting observations over the weekends where students went to bed later but woke later achieving similar sleep length to the school days, the researchers said.

A small group of students (six per cent) who reported less than seven hours of sleep, including a small number reporting not sleeping at all, according to the study,

Therefore, while the average across the week of 72 per cent of students reporting adequate sleep is reassuring, it is far from the goal of every child achieving sleep within the recommended guidelines," Ford said.

Dr Paul Kelly, head of the Sleep Health Service at Canterbury District Health Board, supervised the study and explained that the foundations for good health are based on proper nutrition, regular exercise and good sleep quality.

Sleep quality is often overlooked as a contributory factor to poor health.

"The study findings suggest the need for parental guidance around bedtimings and moderation of the use and availability of electronic devices before bed," Kelly said.

"Respect and protect your sleep, as good daytime functioning is reliant on adequate sleep," Kelly added.

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Agencies
May 18,2020

China, where the novel coronavirus originated, has reported 111 cases since beginning of May, which shows the infection rate has dipped, and 3 deaths since April 27, according to the WHO. A Shanghai-based Noida doctor says China is close to winning the battle against COVID-19, and the combination of zinc, hydroxychloroquine (HCQ) and antibiotic azithromycin has been able to save the lives of coronavirus patients.

Speaking to media persons, Dr Sanjeev Choubey, Medical Director Internal Medicine at St. Michael Hospital said this combination has been adopted as a line of treatment for patients infected with coronavirus, and as a result patients are recovering, decreasing their need for intensive care.

What is the line of treatment for COVID-19 patients, which also include asymptomatic patients?

The combination of zinc, hydroxychloroquine and antibiotic azithromycin has produced positive results, and it helped in the recovery of many COVID-19 patients. The combination -- Ascorbic Acid, B-complex, Zinc, Selenium, L-carnitine, Vitamin B-12 and Glutathione normal saline should be administered on patients twice a week for at least 6 weeks. This is COVID-19 treatment protocol for prophylaxis, and it implies both asymptomatic and symptomatic along with other medicine support.

Based on your experience on COVID-19 in China, after how many tests, is it safe to call a person coronavirus free?

The coronavirus should be performed at least 9 times, before terming a patient COVID-19 free. It is a standard in China. This procedure has worked in China and it will also work in India. Minimum five tests should be mandatory through RT-PCR.

Does coronavirus majorly attack the respiratory system or it could lead to organ failure too?

Line of treatment should not be just looking at the respiratory system, as the problem lies somewhere else. COVID-19 attacks many vital organs in the body. In China, a coronavirus patient died from a stroke. In the autopsy it was found that the innermost layer in the arteries was swollen. It was concluded that coronavirus had inflamed the layer of the arteries leading to clotting, which was a factor in generating a heart attack. Therefore, COVID-19 is not just a respiratory problem.

Amid the coronavirus pandemic, should autopsy be made mandatory in the case of unpredictable death or where reasons for death are not unknown?

Patients below 50 years, who die suddenly and the reasons are not known, then it should be mandatory to conduct the autopsy. After death, coronavirus is active in the body for five days, and it fades away on day 6. Therefore, if an autopsy is done then it will help in understanding this disease. In China, we have seen young COVID-19 patients, aged 22 and 28, succumbed to strokes.

Since the beginning of May, India has recorded more than 2,000 cases everyday in the first week, then it jumped past 3,000 mark in the second week. Finally, the tally is 4,987 on May 17. At 90,927 cases, has India progressed into community transmission or Stage3?

Yes, India has moved into Stage 3. The data suggests that 3,000 to 4,000 active COVID-19 cases, who are asymptomatic, are moving around and spreading the infection. The research has indicated that COVID-19 from an infected person spreads in 30 minutes to non-infected persons. The relaxation on the lockdown will certainly contribute to a high infection rate.

Do you think India has reached its peak in COVID-19 cases, or the sharp rise will continue till July end?

It seems India has already reached its peak and cases will begin to come down from June end or beginning of July first week. If social distancing norms are followed then certainly things can improve, but if not followed then it may get worse. High population density is a major contributor for the increase in cases. The government should continue to focus on finding hotspots, and urge people to follow the rules, eventually it is for people’s own benefit.

Has China won the battle against COVID-19?

It seems China has won the battle by not opening up Wuhan. The Chinese are following a COVID-19 patient’s engagement program, where the authorities continuously interact with people infected with the disease. The Government of India should reward people who follow the guidelines; it will help in setting up a positive trend in the society.

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