Immune cells in the lungs provide a rapid counterattack to bloodstream infections, a new study in mice finds. This surprising discovery pegs the lungs as a major pillar in the body’s defense during these dangerous infections, the researchers say.
“No one would have guessed the lung would provide such an immediate and strong host defense system,” says Bryan Yipp, an immunologist at the University of Calgary in Canada. Yipp and his colleagues report their findings online April 28 in Science Immunology.
The work may offer ways to target and adjust our own immune defense system for infections, says Yipp. “Currently, we only try to kill the bacteria, but we are running out of antibiotics because of resistance.”
The research uncovers some of the mechanisms that drive the rapid activation of neutrophils, says immunologist Andrew Gelman of Washington University School of Medicine in St. Louis. “This is critical in removing bacteria from sequestered spaces in the lung,” he says.
Generally, clearing bacteria out of the bloodstream falls to macrophages that reside in the liver and the spleen. But macrophages aren’t found in vessels of the lungs. So the lungs’ blood vessel network gives pathogens a place to hide and escape the body’s usual removal efforts.
Computer mice have been around in one form or another for the better part of 50 years (or longer, based on your definition of invention), and for most of that time they’ve been paired with mouse pads. But modern optical and laser mice can track on just about any surface, unless you’re somehow using your computer on a sand bed. So do those nerdy-looking pads even serve a purpose anymore?
Yes, actually. A mouse pad isn’t technically necessary these days, but there are some obvious and serious benefits of using one, even if you’re not spending a lot of money on a fancy “gamer” model.
When Did Mouse Pads Start to Disappear?
Some computer users used to simply roll their ancient ball-driven mice along a desktop, presumably using their other hand to shove spears at woolly mammoths. But before the advent of optical mice, mouse pads served some very important functions: not only did they offer a smooth and predictable tracking area, they helped keep the tracking ball clean of dirt, skin oils, and other gunk.
Microsoft and Logitech later introduced consumer-grade optical mice, which ditched the physical roller mechanism for a tiny and low-powered optical sensor and LED combo, around the turn of the century. These offered more consistent tracking on almost any surface (as long as it wasn’t reflective or transparent, like glass) without the possibility of dirt and oil buildup on a conventional ball. A few years later, laser-equipped mice erased even those limitations, and now you can get an inexpensive mouse that will track on more or less any surface.
Consequently, mouse pads began to fall out of fashion. Since optical and laser mice don’t actually contact the surface that they’re tracking (except for the feet of the mouse, which isn’t part of the tracking mechanism), there’s no operational downside to using your desk, or your lap, or the spare…
Plasma taken from human umbilical cords can rejuvenate old mice’s brains and improve their memories, a new study suggests. The results, published online April 19 in Nature, may ultimately help scientists develop ways to stave off aging.
Earlier studies have turned up youthful effects of young mice’s blood on old mice (SN: 12/27/14, p. 21). Human plasma, the new results suggest, confers similar benefits, says study coauthor Joseph Castellano, a neuroscientist at Stanford University. The study also identifies a protein that’s particularly important for the youthful effects, a detail that “adds a nice piece to the puzzle,” Castellano says.
Identifying the exact components responsible for rejuvenating effects is important, says geroscientist Matt Kaeberlein of the University of Washington in Seattle. That knowledge will bring scientists closer to understanding how old tissues can be rejuvenated. And having the precise compounds in hand means that scientists might have an easier time translating therapies to people.
Kaeberlein cautions that the benefits were in mice, not people. Still, he says, “there is good reason to be optimistic that some of these approaches will have similar effects on health span in people.”
Like people, as mice age, brain performance begins to slip. Compared with younger generations, elderly mice perform worse on some tests of learning and memory, taking longer to remember the location of an escape route out of a maze, for instance. Researchers suspect that these deficits come from age-related trouble in the hippocampus, a brain structure important for learning and memory.
Every fourth day for two weeks, Castellano and colleagues injected old mice with human…
Got a mouse in the house? Blame yourself. Not your housekeeping, but your species. Humans never intended to live a mouse-friendly life. But as we moved into a settled life, some animals — including a few unassuming mice — settled in, too. In the process, their species prospered — and took over the world.
The rise and fall of the house mouse’s fortunes followed the stability and instability of the earliest human settlements, a new study shows. By analyzing teeth from ancient mice and comparing the results to modern rodents hanging out near partially settled groups, scientists show that when humans began to settle down, one mouse species seemed to follow. When those people moved on, another species moved in. The findings reveal that human settlement took place long before agriculture began, and that vermin didn’t require a big storehouse of grain to thrive off of us.
Between 15,000 and 11,000 years ago (a time called the Natufian period), people began to form small stone settlements in what is now Israel and Jordan. They were not yet farming or storing grain, but they were living in a single place for a season or two, and coming back to that place relatively often. Those early settlers changed the ecosystem of the world around them — presenting new opportunities for local flora and fauna.
Lior Weissbrod, an archaeologist at the University of Haifa in Israel, started his career wanting to search for clues to the history of animal-human relationships. He was especially interested in animal remains. But, he admits, mouse teeth weren’t exactly his first choice. “[At] the site I was going to work on, the remains of larger animals were already studied,” he says. “I was left with the small mammals.”
Small mammals have even smaller teeth. The largest mouse molars are only about 1 millimeter long. This meant a lot of time sifting dirt through very fine mesh for Weissbrod. He collected 372 mouse teeth from the dirt of five different archaeological sites in modern-day Israel and Jordan, with remains dating from 11,000 to 200,000 years ago. He gave the teeth to his colleague Thomas Cucchi of the National Museum of Natural History in Paris, who developed a technique to classify the mouse teeth by species based on tiny differences in their shape.
The first human…
What happens when you see someone scratch a mosquito bite? You may start to feel an itch come out of nowhere. Then you might start to scratch, too. Mice, new data show, suffer the same strange phenomenon. It’s called contagious scratching.
Tests with mice provide the first clear evidence that contagious scratching can spread mouse-to-mouse, says Zhou-Feng Chen. As a neuroscientist, he studies the brain. He works at the Washington University School of Medicine in St. Louis, Mo. His mice started scratching after watching an itchy neighbor. They even did this after just watching videos of scratching mice.
In discovering this, “there were lots of surprises,” Chen notes. One was that mice would even pay attention to some scratching neighbor. After all, mice are nocturnal. They mostly sniff and use their whiskers to feel their way through the dark. Yet Chen had his own irresistible itch to test the “crazy idea: that mice might share an urge to scratch, he says. And it paid off.
The quirk isn’t just a weird little finding, though. It opens new possibilities for exploring the basis in the brain for picking up such contagious behaviors.
Chen’s group described its new discoveries in the March 10 issue of Science.
How they did it
The researchers housed mice super-itchy mice within sight of some that didn’t scratch much. Then they recorded the animals on video. Shortly after a normal mouse looked at a neighbor scratching, it scratched, too. For a comparison, researchers gave others of these mice a not-very-itchy neighbor. These comparison mice also looked at their neighbor now and then. Rarely, however, would they scratch right after that glance.
And the neighbor didn’t have to be real. Sometimes it was just a mouse video. Animals that viewed the video of scratchers responded the same way. More audience itching and scratching followed the film of a mouse with itchy skin than one…
Cancerous pediatric brain tumors are some of the most aggressive cancers to affect children, and are frequently fatal. They’re difficult to treat due to their proximity to sensitive brain tissue in tiny brains, and children’s bodies can rarely tolerate the side effects of the levels of chemotherapy and radiation necessary to shrink tumors.
But recently, researchers at Stanford Medicine, the Lucile Packard Children’s Hospital, and several other institutions successfully tested a promising immunotherapy treatment that shrank multiple tumor types in mouse models. Immunotherapy treatments harness the body’s own immune system to fight the cancer, and usually come with few to no side effects compared to chemotherapy drugs and radiation.
The collaborative study, published in Science Translational Medicine, showed results on the five most common types of pediatric tumors: Group 3 medulloblastomas (MB), atypical teratoid rhabdoid tumors (ATRT), primitive neuroectodermal tumors (PNET), pediatric glioblastoma (PG), and diffuse intrinsic pontine glioma (DIPG).
The Stanford researchers designed their study after the recent discovery of a molecule known as CD47, a protein expressed on the surface of all cells. CD47 sends a “don’t eat me” signal to the immune system’s macrophages—white blood cells whose job it is to destroy abnormal cells. “Think of the macrophages as the Pac-Man of the immune system,” Samuel Cheshier, lead study author and assistant professor of neurosurgery at Stanford Medicine, tells mental_floss.
Cancer cells have adapted to express high amounts of CD47, essentially fooling the immune system into not destroying their cells, which allows tumors to flourish. Cheshier and his team theorized that if they could block the CD47 signals on cancer cells, the macrophages would identify the cells on the cancerous tumors and eat them—without any toxicity to healthy cells. To do so, they used an antibody known as anti-CD47, which, as its name implies, blocks CD47 on the cancer from binding to a receptor on the macrophage called SIRP-alpha.
“It is this binding that tells the macrophage, ‘Don’t eat the tumor,’” he says. The anti-CD47 fits perfectly into the binding pocket where CD47 and SIRP-alpha interact, “like a jigsaw puzzle,” helping the macrophage correctly identify the tumor as something to be removed. “Anti-CD47 is the big power pill in Pac-Man that makes him able to eat the ghosts,” says Cheshier.
Even better, not only does…
MOUSE SEE, MOUSE ITCH
Catch sight of someone scratching and out of nowhere comes an itch, too. Now, it turns out mice suffer the same strange phenomenon.
Tests with mice that watched itchy neighbors, or even just videos of scratching mice, provide the first clear evidence of contagious scratching spreading mouse-to-mouse, says neuroscientist Zhou-Feng Chen of Washington University School of Medicine in St. Louis. The quirk opens new possibilities for exploring the neuroscience behind the spread of contagious behaviors.
For the ghostly itch, experiments trace scratching to a peptide nicknamed GRP and areas of the mouse brain better known for keeping the beat of circadian rhythms, Chen and colleagues found. They report the results in the March 10 Science.
In discovering this, “there were lots of surprises,” Chen says. One was that mice, nocturnal animals that mostly sniff and whisker-brush their way through the dark, would be sensitive to the sight of another mouse scratching. Yet Chen had his own irresistible itch to test the “crazy idea,” he says.
Researchers housed mice that didn’t scratch any more than normal within sight of mice that flicked and thumped their paws frequently at itchy skin. Videos recorded instances of normal mice looking at an itch-prone mouse mid-scratch and, shortly after, scratching themselves. In comparison, mice with not-very-itchy neighbors looked at those neighbors at…