Shoot for the Moon: Its Surface Contains a Pot of Gold
An astronaut standing on the Moon.
Here's a riddle: What do the Moon, nuclear weapons, clean energy of the future, terrorism, and lung disease all have in common?
One goal of India's upcoming space probe is to locate deposits of helium-3 that are worth trillions of dollars.
The answer is helium-3, a gas that's extremely rare on Earth but 100 million times more abundant on the Moon. This past October, the Lockheed Martin corporation announced a concept for a lunar landing craft that may return humans to the Moon in the coming decade, and yesterday China successfully landed the Change-4 probe on the far side of the Moon. Landing inside the Moon's deepest crater, the Chinese achieved a first in space exploration history.
Meanwhile, later this month, India's Chandrayaan-2 space probe will also land on the lunar surface. One of its goals is to locate deposits of helium-3 that are worth trillions of dollars, because it could be a fuel for nuclear fusion energy to generate electricity or propel a rocket.
The standard way that nuclear engineers are trying to achieve sustainable fusion uses fuels that are more plentiful on Earth: deuterium and tritium. But MIT researchers have found that adding small amounts of helium-3 to the mix could make it much more efficient, and thus a viable energy source much sooner that once thought.
Even if fusion is proven practical tomorrow, any kind of nuclear energy involves long waits for power plant construction measured in decades. However, mining helium-3 could be useful now, because of its non-energy applications. A major one is its ability to detect neutrons coming from plutonium that could be used in terrorist attacks. Here's how it works: a small amount of helium-3 is contained within a forensic instrument. When a neutron hits an atom of helium-3, the reaction produces tritium, a proton, and an electrical charge, alerting investigators to the possibility that plutonium is nearby.
Ironically, as global concern about a potential for hidden nuclear material increased in the early 2000s, so did the supply of helium-3 on Earth. That's because helium-3 comes from the decay of tritium, used in thermonuclear warheads (H-bombs). Thousands of such weapons have been dismantled from U.S. and Russian arsenals, making helium-3 available for plutonium detection, research, and other applications--including in the world of healthcare.
Helium-3 can help doctors diagnose lung diseases, since it enables imaging of the lungs in real time.
Helium-3 dramatically improves the ability of doctors to image the lungs in a range of diseases including asthma, chronic obstructive pulmonary disease and emphysema, cystic fibrosis, and bronchopulmonary dysplasia, which happens particularly in premature infants. Specifically, helium-3 is useful in magnetic resonance imaging (MRI), a procedure that creates images from within the body for diagnostic purposes.
But while a standard MRI allows doctors to visualize parts of the body like the heart or brain, it's useless for seeing the lungs. Because lungs are filled with air, which is much less dense than water or fat, effectively no signals are produced that would enable imaging.
To compensate for this problem, a patient can inhale gas that is hyperpolarized –meaning enhanced with special procedures so that the magnetic resonance signals from the lungs are finally readable. This gas is safe to breathe when mixed with enough oxygen to support life. Helium-3 is one such gas that can be hyperpolarized; since it produces such a strong signal, the MRI can literally see the air inside the lungs and in all of the airways, revealing intricate details of the bronchopulmonary tree. And it can do this in real time
The capability to show anatomic details of the lungs and airways, and the ability to display functional imaging as a patient breathes, makes helium-3 MRI far better than the standard method of testing lung function. Called spirometry, this method tells physicians how the lungs function overall, but does not home in on particular areas that may be causing a problem. Plus, spirometry requires patients to follow instructions and hold their breath, so it is not great for testing young children with pulmonary disease.
In recent years, the cost of helium-3 on Earth has skyrocketed.
Over the past several years, researchers have been developing MRI for lung testing using other hyperpolarized gases. The main alternative to helium-3 is xenon-129. Over the years, researchers have learned to overcome certain disadvantages of the latter, such as its potential to put patients to sleep. Since helium-3 provides the strongest signal, though, it is still the best gas for MRI studies in many lung conditions.
But the supply of helium-3 on Earth has been decreasing in recent years, due to the declining rate of dismantling of warheads, just as the Department of Homeland Security has required more and more of the gas for neutron detection. As a result, the cost of the gas has skyrocketed. Less is available now for medical uses – unless, of course, we begin mining it on the moon.
The question is: Are the benefits worth the 239,000-mile trip?
Catching colds may help protect kids from Covid
A new study shows that the immune system's response to colds can help prepare it to defend against COVID-19 - but only in the very young.
A common cold virus causes the immune system to produce T cells that also provide protection against SARS-CoV-2, according to new research. The study, published last month in PNAS, shows that this effect is most pronounced in young children. The finding may help explain why most young people who have been exposed to the cold-causing coronavirus have not developed serious cases of COVID-19.
One curiosity stood out in the early days of the COVID-19 pandemic – why were so few kids getting sick. Generally young children and the elderly are the most vulnerable to disease outbreaks, particularly viral infections, either because their immune systems are not fully developed or they are starting to fail.
But solid information on the new infection was so scarce that many public health officials acted on the precautionary principle, assumed a worst-case scenario, and applied the broadest, most restrictive policies to all people to try to contain the coronavirus SARS-CoV-2.
One early thought was that lockdowns worked and kids (ages 6 months to 17 years) simply were not being exposed to the virus. So it was a shock when data started to come in showing that well over half of them carried antibodies to the virus, indicating exposure without getting sick. That trend grew over time and the latest tracking data from the CDC shows that 96.3 percent of kids in the U.S. now carry those antibodies.
Antibodies are relatively quick and easy to measure, but some scientists are exploring whether the reactions of T cells could serve as a more useful measure of immune protection.
But that couldn't be the whole story because antibody protection fades, sometimes as early as a month after exposure and usually within a year. Additionally, SARS-CoV-2 has been spewing out waves of different variants that were more resistant to antibodies generated by their predecessors. The resistance was so significant that over time the FDA withdrew its emergency use authorization for a handful of monoclonal antibodies with earlier approval to treat the infection because they no longer worked.
Antibodies got most of the attention early on because they are part of the first line response of the immune system. Antibodies can bind to viruses and neutralize them, preventing infection. They are relatively quick and easy to measure and even manufacture, but as SARS-CoV-2 showed us, often viruses can quickly evolve to become more resistant to them. Some scientists are exploring whether the reactions of T cells could serve as a more useful measure of immune protection.
Kids, colds and T cells
T cells are part of the immune system that deals with cells once they have become infected. But working with T cells is much more difficult, takes longer, and is more expensive than working with antibodies. So studies often lags behind on this part of the immune system.
A group of researchers led by Annika Karlsson at the Karolinska Institute in Sweden focuses on T cells targeting virus-infected cells and, unsurprisingly, saw that they can play a role in SARS-CoV-2 infection. Other labs have shown that vaccination and natural exposure to the virus generates different patterns of T cell responses.
The Swedes also looked at another member of the coronavirus family, OC43, which circulates widely and is one of several causes of the common cold. The molecular structure of OC43 is similar to its more deadly cousin SARS-CoV-2. Sometimes a T cell response to one virus can produce a cross-reactive response to a similar protein structure in another virus, meaning that T cells will identify and respond to the two viruses in much the same way. Karlsson looked to see if T cells for OC43 from a wide age range of patients were cross-reactive to SARS-CoV-2.
And that is what they found, as reported in the PNAS study last month; there was cross-reactive activity, but it depended on a person’s age. A subset of a certain type of T cells, called mCD4+,, that recognized various protein parts of the cold-causing virus, OC43, expressed on the surface of an infected cell – also recognized those same protein parts from SARS-CoV-2. The T cell response was lower than that generated by natural exposure to SARS-CoV-2, but it was functional and thus could help limit the severity of COVID-19.
“One of the most politicized aspects of our pandemic response was not accepting that children are so much less at risk for severe disease with COVID-19,” because usually young children are among the most vulnerable to pathogens, says Monica Gandhi, professor of medicine at the University of California San Francisco.
“The cross-reactivity peaked at age six when more than half the people tested have a cross-reactive immune response,” says Karlsson, though their sample is too small to say if this finding applies more broadly across the population. The vast majority of children as young as two years had OC43-specific mCD4+ T cell responses. In adulthood, the functionality of both the OC43-specific and the cross-reactive T cells wane significantly, especially with advanced age.
“Considering that the mortality rate in children is the lowest from ages five to nine, and higher in younger children, our results imply that cross-reactive mCD4+ T cells may have a role in the control of SARS-CoV-2 infection in children,” the authors wrote in their paper.
“One of the most politicized aspects of our pandemic response was not accepting that children are so much less at risk for severe disease with COVID-19,” because usually young children are among the most vulnerable to pathogens, says Monica Gandhi, professor of medicine at the University of California San Francisco and author of the book, Endemic: A Post-Pandemic Playbook, to be released by the Mayo Clinic Press this summer. The immune response of kids to SARS-CoV-2 stood our expectations on their head. “We just haven't seen this before, so knowing the mechanism of protection is really important.”
Why the T cell immune response can fade with age is largely unknown. With some viruses such as measles, a single vaccination or infection generates life-long protection. But respiratory tract infections, like SARS-CoV-2, cause a localized infection - specific to certain organs - and that response tends to be shorter lived than systemic infections that affect the entire body. Karlsson suspects the elderly might be exposed to these localized types of viruses less often. Also, frequent continued exposure to a virus that results in reactivation of the memory T cell pool might eventually result in “a kind of immunosenescence or immune exhaustion that is associated with aging,” Karlsson says. https://leaps.org/scientists-just-started-testing-a-new-class-of-drugs-to-slow-and-even-reverse-aging/particle-3 This fading protection is why older people need to be repeatedly vaccinated against SARS-CoV-2.
Policy implications
Following the numbers on COVID-19 infections and severity over the last three years have shown us that healthy young people without risk factors are not likely to develop serious disease. This latest study points to a mechanism that helps explain why. But the inertia of existing policies remains. How should we adjust policy recommendations based on what we know today?
The World Health Organization (WHO) updated their COVID-19 vaccination guidance on March 28. It calls for a focus on vaccinating and boosting those at risk for developing serious disease. The guidance basically shrugged its shoulders when it came to healthy children and young adults receiving vaccinations and boosters against COVID-19. It said the priority should be to administer the “traditional essential vaccines for children,” such as those that protect against measles, rubella, and mumps.
“As an immunologist and a mother, I think that catching a cold or two when you are a kid and otherwise healthy is not that bad for you. Children have a much lower risk of becoming severely ill with SARS-CoV-2,” says Karlsson. She has followed public health guidance in Sweden, which means that her young children have not been vaccinated, but being older, she has received the vaccine and boosters. Gandhi and her children have been vaccinated, but they do not plan on additional boosters.
The WHO got it right in “concentrating on what matters,” which is getting traditional childhood immunizations back on track after their dramatic decline over the last three years, says Gandhi. Nor is there a need for masking in schools, according to a study from the Catalonia region of Spain. It found “no difference in masking and spread in schools,” particularly since tracking data indicate that nearly all young people have been exposed to SARS-CoV-2.
Both researchers lament that public discussion has overemphasized the quickly fading antibody part of the immune response to SARS-CoV-2 compared with the more durable T cell component. They say developing an efficient measure of T cell response for doctors to use in the clinic would help to monitor immunity in people at risk for severe cases of COVID-19 compared with the current method of toting up potential risk factors.
In this week's Friday Five: The eyes are the windows to the soul - and biological aging?
Plus, what bean genes mean for health and the planet, a breathing practice that could lower levels of tau proteins in the brain, AI beats humans at assessing heart health, and the benefits of "nature prescriptions"
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on new scientific theories and progress to give you a therapeutic dose of inspiration headed into the weekend.
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Here are the stories covered this week:
- The eyes are the windows to the soul - and biological aging?
- What bean genes mean for health and the planet
- This breathing practice could lower levels of tau proteins
- AI beats humans at assessing heart health
- Should you get a nature prescription?