Monthly Archives: April 2020
Using induced pluripotent stem cells produced from the skin of a patient with a rare, genetic form of insulin-dependent diabetes called Wolfram syndrome, researchers transformed the human stem cells into insulin-producing cells and used the gene-editing tool CRISPR-Cas9 to correct a genetic defect that had caused the syndrome. They then implanted the cells into lab mice and cured the unrelenting diabetes in those mice.
The findings, from researchers at Washington University School of Medicine in St. Louis, suggest the CRISPR-Cas9 technique may hold promise as a treatment for diabetes, particularly the forms caused by a single gene mutation, and it also may be useful one day in some patients with the more common forms of diabetes, such as type 1 and type 2.
Wolfram syndrome is caused by mutations to a single gene, providing the researchers an opportunity to determine whether combining stem cell technology with CRISPR to correct the genetic error also might correct the diabetes caused by the mutation. Patients with Wolfram syndrome develop diabetes during childhood or adolescence and quickly require insulin-replacement therapy, requiring insulin injections multiple times each day. Most go on to develop problems with vision and balance, as well as other issues, and in many patients, the syndrome contributes to an early death.
Researchers at Washington University School of Medicine in St. Louis have transformed stem cells into insulin-producing cells. They used the CRISPR gene-editing tool to correct a defect that caused a form of diabetes, and implanted the cells into mice to reverse diabetes in the animals. Shown is a microscopic image of insulin-secreting beta cells (insulin is green) that were made from stem cells produced from the skin of a patient with Wolfram syndrome.
“This is the first time CRISPR has been used to fix a patient’s diabetes-causing genetic defect and successfully reverse diabetes,” said co-senior investigator Jeffrey R. Millman, PhD, an assistant professor of medicine and of biomedical engineering at Washington University. “For this study, we used cells from a patient with Wolfram syndrome because, conceptually, we knew it would be easier to correct a defect caused by a single gene. But we see this as a stepping stone toward applying gene therapy to a broader population of patients with diabetes.”
The study is published online in the journal Science Translational Medicine.
An experimental coronavirus vaccine developed by Oxford University has protected six monkeys from “heavy quantities” of the pathogen — a promising breakthrough in the worldwide race for a cure.
Researchers at the National Institute of Health Rocky Mountain Laboratory injected the six rhesus macaque monkeys with the Oxford concoction, then exposed them to “heavy quantities” of COVID-19 — exposure that had consistently sickened other monkeys in the lab, the New York Times reported Monday.
But 28 days later, all the chimps were still healthy. After a Swiss team has declared the entire population of Switzerland could get a Covid-19 jab by october, and a new Chinese vaccine that prevents all monkeys heavily infected to get the disease, it is the 3rd hope given to the world in one week for a better future.
Central to a lot of scientific research into aging are tiny caps on the ends of our chromosomes called telomeres. These protective sequences of DNA grow a little shorter each time a cell divides, but by intervening in this process, researchers hope to one day regulate the process of aging and the ill health effects it can bring. A Harvard team is now offering an exciting pathway forward, discovering a set of small molecules capable of restoring telomere length in mice. Telomeres can be thought of like the plastic tips on the end of our shoelaces, preventing the fraying of the DNA code of the genome and playing an important part in a healthy aging process. But each time a cell divides, they grow a little shorter. This sequence repeats over and over until the cell can no longer divide and dies.
This process is linked to aging and disease, including a rare genetic disease called dyskeratosis congenita (DC). This is caused by the premature aging of cells and is where the team focused its attention, hoping to offer alternatives to the current treatment that involves high-risk bone marrow transplants and which offers limited benefits.
One of the ways dyskeratosis congenita comes about is through genetic mutations that disrupt an enzyme called telomerase, which is key to maintaining the structural integrity of the telomere caps. For this reason, researchers have been working to target telomerase for decades, in hopes of finding ways to slow or even reverse the effects of aging and diseases like dyskeratosis congenita.
“Once human telomerase was identified, there were lots of biotech startups, lots of investment,” says Boston Children’s Hospital’s Suneet Agarwal, senior investigator on the new study. “But it didn’t pan out. There are no drugs on the market, and companies have come and gone.”
An experimental COVID-19 vaccine protected monkeys from catching the viral infection, according to an unreviewed report. The new vaccine has now entered clinical trials in China to test the drug in humans.
Although the animal study, posted April 19 to the preprint database bioRxiv, has not been subject to formal review, scientists took to Twitter to share their first impressions.
“So, this is the first ‘serious’ preclinical data I have seen for an actual vaccine candidate,” Florian Krammer, a professor in the Department of Microbiology at the Icahn School of Medicine at Mount Sinai, tweeted on April 22. Before being tested in healthy humans, vaccines undergo so-called preclinical tests in animals. The experimental vaccine, developed by the Beijing-based company Sinovac Biotech, showed promising results in rhesus macaques before entering human trials, Krammer noted. “I’m a fan,” he added in another tweet.
Now in clinical trials, various doses of the vaccine will be given to 144 individuals to determine whether it’s safe, meaning it does not cause dangerous side effects, according to ClinicalTrials.gov. The vaccine would then move into efficacy trials with more than 1,000 additional people to determine whether it triggers an adequate immune response, commented Meng Weining, Sinovac’s senior director for overseas regulatory affairs.
The Sinovac vaccine contains an inactivated version of SARS-CoV-2, the virus that causes COVID-19. By introducing an inactive virus into the body, the vaccine should prompt the immune system to build antibodies that target the pathogen without triggering an actual COVID-19 infection. When given to mice, rats and rhesus macaques, the vaccine sparked the production of such antibodies, according to the bioRxiv report. “This is old-fashioned technology,” which would make the product easy to manufacture, Krammer wrote on Twitter. “What I like most is that many vaccine producers, also in lower–middle-income countries, could make such a vaccine,” he added in an interview
French researchers are planning to test nicotine patches on coronavirus patients and frontline health workers after a study suggested smokers may be much less at risk of contracting the virus.
The study at a major Paris hospital suggests a substance in tobacco – possibly nicotine – may be stopping patients who smoke from catching Covid-19. Clinical trials of nicotine patches are awaiting the approval of the country’s health authorities.
However, the researchers insisted they were not encouraging the population to take up smoking, which carries other potentially fatal health risks and kills 50% of those who take it up. While nicotine may protect those from the virus, smokers who have caught it often develop more serious symptoms because of the toxic effect of tobacco smoke on the lungs, they say.
The team at Pitié-Salpêtrière hospital questioned 480 patients who tested positive for the virus, 350 of whom were hospitalised while the rest with less serious symptoms were allowed home. It found that of those admitted to hospital, whose median age was 65, only 4.4% were regular smokers. Among those released home, with a median age of 44, 5.3% smoked. Taking into account the age and sex of the patients, the researchers discovered the number of smokers was much lower than that in the general population estimated by the French health authority Santé Publique France at about 40% for those aged 44-53 and between 8.8% and 11.3% for those aged 65-75.
The renowned French neurobiologist Jean-Pierre Changeux, who reviewed the study, suggested the nicotine might stop the virus from reaching cells in the body preventing its spread. Nicotine may also lessen the overreaction of the body’s immune system that has been found in the most severe cases of Covid-19 infection.
The findings are to be verified in a clinical study in which frontline health workers, hospital patients with the Covid-19 virus and those in intensive care will be given nicotine patches. The results confirm a Chinese study published at the end of March in the New England Journal of Medicine that suggested only 12.6% of 1,000 people infected with the virus were smokers while the number of smokers in China is around 28%. In France, figures from Paris hospitals showed that of 11,000 patients admitted to hospital with Covid-19, 8.5% were smokers. The total number of smokers in France is estimated at around 25.4%.
“Our cross-sectional study strongly suggests that those who smoke every day are much less likely to develop a symptomatic or severe infection with Sars-CoV-2 compared with the general population,” the Pitié-Salpêtrière report authors wrote. “The effect is significant. It divides the risk by five for ambulatory patients and by four for those admitted to hospital. We rarely see this in medicine,” it added.
A team of researchers from Empa, ETH Zurich and Zurich University Hospital has succeeded in developing a novel sensor for detecting the new coronavirus. In future it could be used to measure the concentration of the virus in the environment – for example in places where there are many people or in hospital ventilation systems.
Jing Wang and his team at Empa and ETH Zurich usually work on measuring, analyzing and reducing airborne pollutants such as aerosols and artificially produced nanoparticles. However, the challenge the whole world is currently facing is also changing the goals and strategies in the research laboratories. The new focus: a sensor that can quickly and reliably detect SARS-CoV-2 – the new coronavirus.
But the idea is not quite so far removed from the group’s previous research work: even before the COVID-19 began to spread, first in China and then around the world, Wang and his colleagues were researching sensors that could detect bacteria and viruses in the air. The sensor will not necessarily replace the established laboratory tests, but could be used as an alternative method for clinical diagnosis, and more prominently to measure the virus concentration in the air in real time: For example, in busy places like train stations or hospitals.
Fast and reliable tests for the new coronavirus are urgently needed to bring the pandemic under control as soon as possible. Most laboratories use a molecular method called reverse transcription polymerase chain reaction, or RT-PCR for short, to detect viruses in respiratory infections. This is well established and can detect even tiny amount of viruses – but at the same time it can be time consuming and prone to error.
Jing Wang and his team have developed an alternative test method in the form of an optical biosensor. The sensor combines two different effects to detect the virus safely and reliably: an optical and a thermal one.
The sensor uses an optical and a thermal effect to detect the COVID-19-Virus safely and reliably
The sensor is based on tiny structures of gold, so-called gold nanoislands, on a glass substrate. Artificially produced DNA receptors that match specific RNA sequences of the SARS-CoV-2 are grafted onto the nanoislands. The coronavirus is a so-called RNA virus: Its genome does not consist of a DNA double strand as in living organisms, but of a single RNA strand. The receptors on the sensor are therefore the complementary sequences to the virus’ unique RNA sequences, which can reliably identify the virus.
The technology the researchers use for detection is called LSPR, short for localized surface plasmon resonance. This is an optical phenomenon that occurs in metallic nanostructures: When excited, they modulate the incident light in a specific wavelength range and create a plasmonic near-field around the nanostructure. When molecules bind to the surface, the local refractive index within the excited plasmonic near-field changes. An optical sensor located on the back of the sensor can be used to measure this change and thus determine whether the sample contains the RNA strands in question.
The U.S. will need to administer 20 million tests for the novel coronavirus each day by mid-summer in order to fully remobilize the economy in a safe fashion, according to new report from a Harvard panel of more than 45 experts in health, science and economics. The figure far exceeds testing recommendations from other health experts. Former Food and Drug Administration (FDA) Commissioner Scott Gottlieb has said that the country will need to initially conduct up to 3 million tests per week to reopen. A separate estimate from Harvard University researchers says the U.S. must conduct between 500,000 and 700,00 tests per day by mid-May to begin reopening.
The new report, released by Harvard University’s Edmond J. Safra Center for Ethics on Monday, emphasized the need for a massive scaling up of testing coupled with a robust contact-tracing program in order to reopen the U.S. in a way that avoids future shutdowns. Its top recommendations include a call for the nation to deliver 5 million tests per day by early June in order to ensure a safe reopening of portions of the economy.
“This number will need to increase over time (ideally by late July) to 20 million a day to fully remobilize the economy,” the authors wrote, cautioning that even that figure may not be high enough to “protect public health.”
The value in dramatically increasing testing is it will “prevent cycles of opening up and shutting down,” the authors argued, adding that the testing output will allow the virus to be adequately managed until a vaccine is developed.
“This Roadmap is the only approach to BOTH contain the virus and ramp back up to vibrant economic life. And, in the long term, it allows us to build an infrastructure of pandemic resilience that will serve us well when the next health crisis or disaster hits, while improving community health,” Danielle Allen, director of Harvard University’s Edmond J. Safra Center for Ethics, said in a statement.
A new version of a breathing aid that can help coronavirus patients has been developed in less a week by a team involving Mercedes Formula One, and is being trialed at London hospitals.
Continuous Positive Airway Pressure (CPAP) devices have been used in China and Italy to deliver air and oxygen under pressure to patients’ lungs to help them breathe without the need for them to go on a ventilator, a more invasive process.
The new CPAP has already been approved by the relevant regulator and now 100 of the machines will be delivered to University College London Hospital (UCLH) for trials, before being rolled out to other hospitals.
Reports from Italy indicate that approximately 50% of patients given CPAP have avoided the need for invasive mechanical ventilation, which involves patients being sedated, freeing up ventilators for those more in need.
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“These devices will help to save lives by ensuring that ventilators, a limited resource, are used only for the most severely ill,” UCLH critical care consultant Professor Mervyn Singer said in a statement.
“We hope they will make a real difference to hospitals across the UK by reducing demand on intensive care staff and beds, as well as helping patients recover without the need for more invasive ventilation.”
Emitting light from silicon has been the ‘Holy Grail’ in the microelectronics industry for decades. Solving this puzzle would revolutionize computing, as chips will become faster than ever. Researchers from Eindhoven University of Technology (TU-e) now succeeded: they have developed an alloy with silicon that can emit light. The team will now start creating a silicon laser to be integrated into current chips.
Every year we use and produce significantly more data. But our current technology, based on electronic chips, is reaching its ceiling. The limiting factor is heat, resulting from the resistance that the electrons experience when traveling through the copper lines connecting the many transistors on a chip. If we want to continue transferring more and more data every year, we need a new technique that does not produce heat. Bring in photonics, which uses photons (light particles) to transfer data. In contrast to electrons, photons do not experience resistance. As they have no mass or charge, they will scatter less within the material they travel through, and therefore no heat is produced. The energy consumption will therefore be reduced. Moreover, by replacing electrical communication within a chip by optical communication, the speed of on-chip and chip-to-chip communication can be increased by a factor 1000. Data centers would benefit most, with faster data transfer and less energy usage for their cooling system. But these photonic chips will also bring new applications within reach. Think of laser-based radar for self-driving cars and chemical sensors for medical diagnosis or for measuring air and food quality.
To use light in chips, you will need a light source; an integrated laser. The main semiconductor material that computer chips are made of is silicon. But bulk silicon is extremely inefficient at emitting light, and so was long thought to play no role in photonics. Thus, scientists turned to more complex semiconductors, such as gallium arsenide and indium phosphide. These are good at emitting light but are more expensive than silicon and are hard to integrate into existing silicon microchips.
To create a silicon compatible laser, scientists needed to produce a form of silicon that can emit light. That’s exactly what researchers from Eindhoven University of Technology (TU/e) now succeeded in. Together with researchers from the universities of Jena, Linz and Munich, they combined silicon and germanium in a hexagonal structure that is able to emit light. A breakthrough after 50 years of work.
Nanowires with hexagonal silicon-germanium shells
“The crux is in the nature of the so-called band gap of a semiconductor,” says lead researcher Erik Bakkers from TU/e. “If an electron ‘drops’ from the conduction band to the valence band, a semiconductor emits a photon: light.” But if the conduction band and valence band are displaced with respect to each other, which is called an indirect band gap, no photons can be emitted – as is the case in silicon. “A 50-year old theory showed however that silicon, alloyed with germanium, shaped in a hexagonal structure does have a direct band gap, and therefore potentially could emit light,” explains Bakkers.
Shaping silicon in a hexagonal structure, however, is not easy. As Bakkers and his team master the technique of growing nanowires, they were able to create hexagonal silicon in 2015. They realized pure hexagonal silicon by first growing nanowires made from another material, with a hexagonal crystal structure. Then they grew a silicon-germanium shell on this template. Elham Fadaly, shared first author of the study: “We were able to do this such that the silicon atoms are built on the hexagonal template, and by this forced the silicon atoms to grow in the hexagonal structure.” But they could not yet make them to emit light, until now. Bakkers team managed to increase the quality of the hexagonal silicon-germanium shells by reducing the number of impurities and crystal defects. When exciting the nanowire with a laser, they could measure the efficiency of the new material. Alain Dijkstra, also shared first author of the study and responsible for measuring the light emission: “Our experiments showed that the material has the right structure, and that it is free of defects. It emits light very efficiently.”
The findings have been published in the journal Nature.