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We finally know what causes childhood leukemia — and how to prevent it
A number of different things have to happen for a child to develop leukemia.
The cause of the most common type of childhood cancer has been a century-long debate among those in the medical community. Now, thanks to the work of Prof. Mel Greaves, of the Institute of Cancer Research in London, the mystery is at its end. Acute lymphoblastic leukemia (ALL) affects 1 in 2,000 children. Ironically, it's our modern germ-free lifestyle, particularly our high level of cleanliness, that contributes to the disease's formation. What's really exciting is that we may even have the knowledge we need to make ALL a thing of the past.
To make this breakthrough, Prof. Greaves conducted a meta-analysis, combing through 30 years of medical literature and gathering data from colleagues all across the globe. His search included research on genetics, epidemiology, immunology, cellular biology, and much more. Along this journey, Prof. Greaves ruled out chemicals in the environment, ionizing radiation, electromagnetic waves, and the influence of high tension wires (electrical cables) as possible causes.
Putting together so many disparate puzzle pieces and eliminating false causes allowed him to formulate a “unified theory of leukemia." Although a horrifying condition for a child and parents to endure, Prof. Greaves' analysis, published in the journal Nature Reviews Cancer, has a bright spot. This type of leukemia may be wholly preventable.
A lack of exposure to microbes in the environment contributes to ALL. Image credit: Donnie Ray Jones, Flickr.
This exhaustive work supports the “delayed infection theory." According to Prof. Greaves, “The research study strongly suggests that acute lymphoblastic leukemia has a clear biological cause and is activated by a variety of infections in predisposed kids whose immune systems have not been properly primed."
Children born with a certain genetic mutation have merely the potential for developing ALL. This mutation takes place by accident within the womb. It will remain latent until the second “hit" comes, when the immune system fails to encounter enough microbes during the first year of life to prime it, or in other words train it.
A healthy amount of germ exposure allows the immune system to learn how to deal with pathogens correctly. If the infant grows into childhood without exposure to microbes from the environment or other children, they may develop ALL. But it takes a run-of-the-mill infection later on to ultimately trigger this form of leukemia. All told, full-blown ALL only occurs in 1% of cases where the mutation is present. The absence of pathogens as a factor explains why this form of childhood leukemia is common in wealthy, developed countries, but nearly absent in developing ones.
Allowing young children to play with older ones and be exposed to microbes in the environment could prevent ALL. Image credit: Pixababy.
What's fascinating is some of the disparate pieces of the puzzle Prof. Greaves put together to formulate this discovery. For instance, one clue was an outbreak of swine flu in Milan, which resulted in seven children developing ALL. Another clue was that infants born vaginally over cesarean section have a lower risk of developing this form of cancer.
That's because infants passing through the vaginal canal are exposed to more microbes than those born through c-section. Also, infants who are breastfed have less of a risk, as they often pickup healthy bacteria this way. On another front, animals, particularly mice, when living in an environment devoid of pathogens, often develop leukemia.
Prof. Greaves urges parents not to worry too much about keeping a clean house, and he offer some tips for preventing the disease, which include being less worried about normal, run-of-the-mill infections, and allowing young children to play with other kids, especially older children.
This research may even someday help us prevent the onset of other autoimmune disorders, including type 1 diabetes and allergies. In the future, giving young children a special yogurt drink or somehow purposefully exposing them to healthy microbes could help prevent ALL and perhaps other autoimmune conditions as well.
To hear Prof. Greaves explain his breakthrough himself, click here:
All this from a wad of gum?
- Researchers recently uncovered a piece of chewed-on birch pitch in an archaeological dig in Denmark.
- Conducting a genetic analysis of the material left in the birch pitch offered a plethora of insights into the individual who last chewed it.
- The gum-chewer has been dubbed Lola. She lived 5,700 years ago; and she had dark skin, dark hair, and blue eyes.
Five thousand and seven hundred years ago, "Lola" — a blue-eyed woman with dark skin and hair — was chewing on a piece of pitch derived from heating birch bark. Then, this women spit her chewing gum out into the mud on an island in Denmark that we call Syltholm today, where it was unearthed by archaeologists thousands of years later. A genetic analysis of the chewing gum has provided us with a wealth of information on this nearly six-thousand-year-old Violet Beauregarde.
This represents the first time that the human genome has been extracted from material such as this. "It is amazing to have gotten a complete ancient human genome from anything other than bone," said lead researcher Hannes Schroeder in a statement.
"What is more," he added, "we also retrieved DNA from oral microbes and several important human pathogens, which makes this a very valuable source of ancient DNA, especially for time periods where we have no human remains."
In the pitch, researchers identified the DNA of the Epstein-Barr virus, which infects about 90 percent of adults. They also found DNA belonging to hazelnuts and mallards, which were likely the most recent meal that Lola had eaten before spitting out her chewing gum.
Insights into ancient peoples
The birch pitch was found on the island of Lolland (the inspiration for Lola's name) at a site called Syltholm. "Syltholm is completely unique," said Theis Jensen, who worked on the study for his PhD. "Almost everything is sealed in mud, which means that the preservation of organic remains is absolutely phenomenal.
"It is the biggest Stone Age site in Denmark and the archaeological finds suggest that the people who occupied the site were heavily exploiting wild resources well into the Neolithic, which is the period when farming and domesticated animals were first introduced into southern Scandinavia."
Since Lola's genome doesn't show any of the markers associated with the agricultural populations that had begun to appear in this region around her time, she provides evidence for a growing idea that hunter-gatherers persisted alongside agricultural communities in northern Europe longer than previously thought.
Her genome supports additional theories on northern European peoples. For example, her dark skin bolsters the idea that northern populations only recently acquired their light-skinned adaptation to the low sunlight in the winter months. She was also lactose intolerant, which researchers believe was the norm for most humans prior to the agricultural revolution. Most mammals lose their tolerance for lactose once they've weaned off of their mother's milk, but once humans began keeping cows, goats, and other dairy animals, their tolerance for lactose persisted into adulthood. As a descendent of hunter-gatherers, Lola wouldn't have needed this adaptation.
A hardworking piece of gum
A photo of the birch pitch used as chewing gum.
These findings are encouraging for researchers focusing on ancient peoples from this part of the world. Before this study, ancient genomes were really only ever recovered from human remains, but now, scientists have another tool in their kit. Birch pitch is commonly found in archaeological sites, often with tooth imprints.
Ancient peoples used and chewed on birch pitch for a variety of reasons. It was commonly heated up to make it pliable, enabling it to be molded as an adhesive or hafting agent before it settled. Chewing the pitch may have kept it pliable as it cooled down. It also contains a natural antiseptic, and so chewing birch pitch may have been a folk medicine for dental issues. And, considering that we chew gum today for no other reason than to pass the time, it may be that ancient peoples chewed pitch for fun.
Whatever their reasons, chewed and discarded pieces of birch pitch offer us the mind-boggling option of learning what someone several thousands of years ago ate for lunch, or what the color of their hair was, their health, where their ancestors came from, and more. It's an unlikely treasure trove of information to be found in a mere piece of gum.
The non-contact technique could someday be used to lift much heavier objects — maybe even humans.
- Since the 1980s, researchers have been using sound waves to move matter through a technique called acoustic trapping.
- Acoustic trapping devices move bits of matter by emitting strategically designed sound waves, which interact in such a way that the matter becomes "trapped" in areas of particular velocity and pressure.
- Acoustic and optical trapping devices are already used in various fields, including medicine, nanotechnology, and biological research.
Sound can have powerful effects on matter. After all, sound strikes our world in waves — vibrations of air molecules that bounce off of, get absorbed by, or pass through matter around us. Sound waves from a trained opera singer can shatter a wine glass. From a jet, they can collapse a stone wall. But sound can also be harnessed for delicate interactions with matter.
Since the 1980s, researchers have been using sound to move matter through a phenomenon called acoustic trapping. The method is based on the fact that sound waves produce an acoustic radiation force.
"When an acoustic wave interacts with a particle, it exerts both an oscillatory force and a much smaller steady-state 'radiation' force," wrote the American Physical Society. "This latter force is the one used for trapping and manipulation. Radiation forces are generated by the scattering of a traveling sound wave, or by energy gradients within the sound field."
When tiny particles encounter this radiation, they tend to be drawn toward regions of certain pressure and velocity within the sound field. Researchers can exploit this tendency by engineering sound waves that "trap" — or suspend — tiny particles in the air. Devices that do this are often called "acoustic tweezers."
Building a better tweezer
A study recently published in the Japanese Journal of Applied Physics describes how researchers created a new type of acoustic tweezer that was able to lift a small polystyrene ball into the air.
Tweezers of Sound: Acoustic Manipulation off a Reflective Surface youtu.be
It is not the first example of a successful "acoustic tweezer" device, but the new method is likely the first to overcome a common problem in acoustic trapping: sound waves bouncing off reflective surfaces, which disrupts acoustic traps.
To minimize the problems of reflectivity, the team behind the recent study configured ultrasonic transducers such that the sound waves that they produce overlap in a strategic way that is able to lift a small bit of polystyrene from a reflective surface. By changing how the transducers emit sound waves, the team can move the acoustic trap through space, which moves the bit of matter.
Move, but don't touch
So far, the device is only able to move millimeter-sized pieces of matter with varying degrees of success. "When we move a particle, it sometimes scatters away," the team noted. Still, improved acoustic trapping and other no-contact lifting technologies — like optical tweezers, commonly used in medicine — could prove useful in many future applications, including cell separation, nanotechnologies, and biological research.
Could future acoustic-trapping devices lift large and heavy objects, maybe even humans? It seems possible. In 2018, researchers from the University of Bristol managed to acoustically trap particles whose diameters were larger than the sound wavelength, which was a breakthrough because it surpassed "the classical Rayleigh scattering limit that has previously restricted stable acoustic particle trapping," the researchers wrote in their study.
In other words, the technique — which involved suspending matter in tornado-like acoustic traps — showed that it is possible to scale up acoustic trapping.
"Acoustic tractor beams have huge potential in many applications," Bruce Drinkwater, co-author of the 2018 study, said in a statement. "I'm particularly excited by the idea of contactless production lines where delicate objects are assembled without touching them."
Australian parrots have worked out how to open trash bins, and the trick is spreading across Sydney.
- If sharing learned knowledge is a form of culture, Australian cockatoos are one cultured bunch of birds.
- A cockatoo trick for opening trash bins to get at food has been spreading rapidly through Sydney's neighborhoods.
- But not all cockatoos open the bins; some just stay close to those that do.
Dumpster-diving trash parrots
In a study about these smart birds just published in Science, researchers define animal culture as "population-specific behaviors acquired via social learning from knowledgeable individuals."
Co-lead author of the study Barbara Klump of the Max Planck Institute of Animal Behavior in Konstanz, Germany says, "[C]ompared to humans, there are few known examples of animals learning from each other. Demonstrating that food scavenging behavior is not due to genetics is a challenge."
An opportunity presented itself in a video that co-author Richard Major of the Australian Museum shared with Klump and the other co-authors. In the video, a sulphur-crested cockatoo used its beak to pull up the handle of a closed garbage bin — using its foot as a wedge — and then walked back the lid sufficiently to flip it open, exposing the bin's edible contents.
Major has been studying Cacatua galerita for 20 years and says, "Like many Australian birds, sulphur-crested cockatoos are loud and aggressive." The study describes them as a "large-brained, long-lived, and highly social parrot." Says Major, "They are also incredibly smart, persistent, and have adapted brilliantly to living with humans."(Research regarding some of the ways in which wild animals adapt to the presence of humans has already produced some fascinating results and is ongoing.)
Clever cockie opens bin - 01 youtu.be
The researchers became curious about how widespread this behavior might be and saw a research opportunity. After all, says John Martin, a researcher at Taronga Conservation Society, "Australian garbage bins have a uniform design across the country, and sulphur-crested cockatoos are common across the entire east coast."
Martin continues, "In 2018, we launched an online survey in various areas across Sydney and Australia with questions such as, 'What area are you from, have you seen this behavior before, and if so, when?'"
Word gets around
Credit: magspace/Adobe Stock
Although the cockatoos' maneuver was reported in only three suburbs before 2018, by the end of 2019, people in 44 areas reported observing the behavior. Clearly, more and more cockatoos were learning how to successfully dumpster dive.
As further proof, says Klump, "We observed that the birds do not open the garbage bins in the same way, but rather used different opening techniques in different suburbs, suggesting that the behavior is learned by observing others." One individual bird in north Sydney invented its own method, and the scientists saw it grow in popularity throughout the local population.
To track individual birds, the researchers marked 500 cockatoos with small red dots. Subsequent observations revealed that not all cockatoos are bin-openers. Only about 10 percent of them are, and they are mostly males. The other cockatoos apparently restrict their education to a different lesson: hang around with a bin-opener, and you will get supper.
Thanks to the surveys, the researchers consider the entire project to be a valuable citizen-science experiment. "By studying this behavior with the help of local residents, we are uncovering the unique and complex cultures of their neighborhood birds."
The few seconds of nuclear explosion opening shots in Godzilla alone required more than 6.5 times the entire budget of the monster movie they ended up in.