Taking antidepressants during pregnancy does not increase the risk of autism or attention-deficit/hyperactivity disorder, two new large studies suggest. Genetic or environmental influences, rather than prenatal exposure to the drugs, may have a greater influence on whether a child will develop these disorders. The studies are published online April 18 in JAMA.

Clinically, the message is “quite reassuring for practitioners and for mothers needing to make a decision about antidepressant use during pregnancy,” says psychiatrist Simone Vigod, a coauthor of one of the studies. Past research has questioned the safety of expectant moms taking antidepressants (SN: 6/5/10, p. 22).
“A mother’s mood disturbances during pregnancy are a big public health issue — they impact the health of mothers and their children,” says Tim Oberlander, a developmental pediatrician at the University of British Columbia in Vancouver. About one in 10 women develop a major depressive episode during pregnancy. “All treatment options should be explored. Nontreatment is never an option,” says Oberlander, who coauthored a commentary, also published in JAMA.

Untreated depression during pregnancy creates risks for the child, including poor fetal growth, preterm birth and developmental problems. Some women may benefit from psychotherapy alone. A more serious illness may require antidepressants. “Many of us have started to look at longer term child outcomes related to antidepressant exposure because mothers want to know about that in the decision-making process,” says Vigod, of Women’s College Hospital in Toronto.

Previous studies indicated that the use of antidepressants came with its own developmental risks: autism spectrum disorder, ADHD, premature birth and poor fetal growth. “The key question is whether those risks are due to the actual medication,” says psychologist Brian D’Onofrio of Indiana University Bloomington. “Could the negative outcomes be due to the depression itself, or stress or genetic factors?” D’Onofrio and his group authored the other study.

To attempt to isolate the impact of antidepressants on exposed children, both studies relied on big sample sizes and sophisticated statistical techniques. D’Onofrio’s team looked at more than 1.5 million Swedish children born from 1996 to 2012 to nearly 950,000 mothers. More than 22,000, or 1.4 percent, of these kids had mothers who reported using antidepressants, mostly selective serotonin reuptake inhibitors, in the first trimester.
The researchers compared siblings in families where the mother used antidepressants in one pregnancy but not the other. “This helps account for all of the factors that make siblings similar — their shared genetics and environment,” D’Onofrio says.
In the sibling matchup, the children had essentially the same risk for autism, ADHD and poor fetal growth whether they were exposed to antidepressants in the womb or not. There remained a small increased risk of preterm birth among exposed siblings compared to their unexposed siblings.

In the whole sample, looking at antidepressant use only without accounting for other possible influences, “children have roughly twice the risk of having autism if the mother takes antidepressant medication during the first trimester,” says D’Onofrio. “But that association goes completely away when you compare siblings.” Although it’s not clear exactly what’s responsible for the increased risk — depression, stress, genetic factors, poor prenatal care — “our results suggest that it is actually not due to the medication itself,” he says.

Vigod and colleagues looked at mothers who qualified for public drug coverage in Ontario, Canada, from 2002 to 2010. The women gave birth to 35,906 children; in 2,837 of those pregnancies, nearly 8 percent, the women took antidepressants, also primarily selective serotonin reuptake inhibitors. The team compared exposed children to their unexposed siblings, too, and found no association between autism risk and antidepressant use.

“The use of sibling matches in both studies is a very innovative way to account for genetics and a shared environment,” says Oberlander. “We can’t ignore the fact that there are shared genetic mechanisms that might relate autism and depression. The genetic reason that brought the mom to use the drug may say more about the risk of autism in the child.”

If the Milky Way exists in the biggest cosmic void ever observed, that could solve a puzzling mismatch between ways to measure how fast the universe is expanding.

Observations of 120,000 galaxies bolstering the Milky Way’s loner status were presented by Benjamin Hoscheit June 7 at a meeting of the American Astronomical Society in Austin, Texas. Building on earlier work by his adviser, University of Wisconsin‒Madison astronomer Amy Barger, Hoscheit and Barger measured how the density of galaxies changed with distance from the Milky Way.
In agreement with the earlier study, the pair found that the Milky Way has far fewer neighbors than it should. There was a rise in density about 1 billion light-years out, suggesting the Milky Way resides in an abyss about 2 billion light-years wide.

Simulations of how cosmic structures form suggest that most galaxies clump along dense filaments of dark matter, which are separated by vast cosmic voids.

If the Milky Way lives in such a void, it could help explain why the universe seems to be expanding at different rates depending on how it’s measured (SN: 8/6/16, p. 10). Measurements based on the cosmic microwave background, the earliest light in the universe, suggest one rate of expansion, while measurements of nearby supernovas suggest a faster one.

Those supernovas could be feeling an extra gravitational pull from all the matter at the edges of the void, Hoscheit says. The actual expansion rate is probably the slower one measured in the universe’s early light.

“If you don’t account for the void effects, you could mistake this relationship to indicate that there is too much expansion,” Hoscheit says.

The hunt for gravitational waves is moving upward. A space-based detector called the Laser Interferometer Space Antenna, or LISA, was selected as a mission in the European Space Agency’s science program, the agency announced June 20.

LISA will consist of three identical satellites arranged in a triangle that will cartwheel through space in orbit around the sun just behind Earth. The spacecraft will use lasers to detect changes in the distance between each satellite. Those changes would indicate the passage of gravitational waves, the ripples in spacetime that massive bodies such as black holes shake off when they move.

The spacecraft was originally planned as a joint mission between ESA and NASA, but NASA pulled out in 2011 citing budget issues. In December 2015, ESA launched a single satellite called LISA Pathfinder to test the concept — a test it passed with flying colors.

Interest in LISA increased in 2016 after researchers at the ground-based LIGO detectors announced that they had finally observed gravitational waves. LIGO is best suited for detecting the crash caused when dense objects such as neutron stars or solar-mass black holes collide.

LISA, on the other hand, will be sensitive to the collision of much more massive objects — such as the supermassive black holes that make up most galaxies’ cores.

The mission design and cost are still being completed. If all goes as planned, LISA will launch in 2034.

Pigs are a step closer to becoming organ donors for people.

Researchers used molecular scissors known as CRISPR/Cas9 to snip embedded viruses out of pig DNA. Removing the viruses — called porcine endogenous retroviruses, or PERVs — creates piglets that can’t pass the viruses on to transplant recipients, geneticist Luhan Yang and colleagues report online August 10 in Science.

Yang, a cofounder of eGenesis in Cambridge, Mass., and colleagues had previously sliced 62 PERVs at a time from pig cells grown in the lab (SN: 11/14/15, p. 6). Many of the embedded viruses are already damaged and can’t make copies of themselves to pass on an infection. So in the new study, the researchers removed just 25 viruses that were still capable of infecting other cells.
The team had to overcome several technical hurdles to make PERV-less pig cells that still had the normal number of chromosomes. In a process similar to the one that created Dolly the Sheep (SN: 3/1/97, p. 132), researchers sucked the DNA-containing nuclei from the virus-cleaned cells and injected them into pig eggs. The technique, called somatic cell nuclear transfer, is better known as cloning. Embryos made from the cloned cells were transplanted to sows to develop into piglets.

The process is still not very efficient. Researchers placed 200 to 300 embryos in each of 17 sows. Only 37 piglets were born, and 15 are still living. The oldest are about 4 months old. Such virus-free swine could be a starting point for further genetic manipulations to make pig organs compatible with humans.

As the moon’s shadow races across North America on August 21, hundreds of radio enthusiasts will turn on their receivers — rain or shine. These observers aren’t after the sun. They’re interested in a shell of electrons hundreds of kilometers overhead, which is responsible for heavenly light shows, GPS navigation and the continued existence of all earthly beings.

This part of the atmosphere, called the ionosphere, absorbs extreme ultraviolet radiation from the sun, protecting life on the ground from its harmful effects. “The ionosphere is the reason life exists on this planet,” says physicist Joshua Semeter of Boston University.
It’s also the stage for brilliant displays like the aurora borealis, which appears when charged material in interplanetary space skims the atmosphere. And the ionosphere is important for the accuracy of GPS signals and radio communication.

This layer of the atmosphere forms when radiation from the sun strips electrons from, or ionizes, atoms and molecules in the atmosphere between about 75 and 1,000 kilometers above Earth’s surface. That leaves a zone full of free-floating negatively charged electrons and positively charged ions, which warps and wefts signals passing through it.
Without direct sunlight, though, the ionosphere stops ionizing. Electrons start to rejoin the atoms and molecules they abandoned, neutralizing the atmosphere’s charge. With fewer free electrons bouncing around, the ionosphere reflects radio waves differently, like a distorted mirror.
We know roughly how this happens, but not precisely. The eclipse will give researchers a chance to examine the charging and uncharging process in almost real time.

“The eclipse lets us look at the change from light to dark to light again very quickly,” says Jill Nelson of George Mason University in Fairfax, Va.

Joseph Huba and Douglas Drob of the U.S. Naval Research Laboratory in Washington, D.C., predicted some of what should happen to the ionosphere in the July 17 Geophysical Research Letters. At higher altitudes, the electrons’ temperature should decrease by 15 percent. Between 150 and 350 kilometers above Earth’s surface, the density of free-floating electrons should drop by a factor of two as they rejoin atoms, the researchers say. This drop in free-floating electrons should create a disturbance that travels along Earth’s magnetic field lines. That echo of the eclipse-induced ripple in the ionosphere may be detectable as far away as the tip of South America.

Previous experiments during eclipses have shown that the degree of ionization doesn’t simply die down and then ramp back up again, as you might expect. The amount of ionization you see seems to depend on how far you are from being directly in the moon’s shadow.

For a project called Eclipse Mob, Nelson and her colleagues will use volunteers around the United States to gather data on how the ionosphere responds when the sun is briefly blocked from the largest land area ever.
About 150 Eclipse Mob participants received a build-it-yourself kit for a small radio receiver that plugs into the headphone jack of a smartphone. Others made their own receivers after the project ran out of kits. On August 21, the volunteers will receive signals from radio transmitters and record the signal’s strength before, during and after the eclipse.
Nelson isn’t sure what to expect in the data, except that it will look different depending on where the receivers are. “We’ll be looking for patterns,” she says. “I don’t know what we’re going to see.”

Semeter and his colleagues will be looking for the eclipse’s effect on GPS signals. They would also like to measure the eclipse’s effects on the ionosphere using smartphones — eventually.

For this year’s solar eclipse, they will observe radio signals using an existing network of GPS receivers in Missouri, and intersperse it with small, cheap GPS receivers that are similar to the kind in most phones. The eclipse will create a big cool spot, setting off waves in the atmosphere that will propagate away from the moon’s shadow. Such waves leave an imprint on the ionosphere that affects GPS signals. The team hopes to combine high-quality data with messier data to lay the groundwork for future experiments to tap into the smartphone crowd.

“The ultimate vision of this project is to leverage all 2 billion smartphones around the planet,” Semeter says. Someday, everyone with a phone could be a node in a global telescope.

If it works, it could be a lifesaver. Similar atmospheric waves were seen radiating from the source of the 2011 earthquake off the coast of Japan (SN Online: 6/16/11). “The earthquake did the sort of thing the eclipse is going to do,” Semeter says. Understanding how these waves form and move could potentially help predict earthquakes in the future.

Carbondale, Ill., is just a few kilometers north of the point where this year’s total solar eclipse will linger longest — the city will get two minutes and 38 seconds of total darkness when the moon blocks out the sun. And it’s the only city in the United States that will also be in the path of totality when the next total solar eclipse crosses North America, in 2024 (SN: 8/5/17, p. 32). The town is calling itself the Eclipse Crossroads of America.
“Having a solar eclipse that goes through the entire continent is rare enough,” says planetary scientist Padma Yanamandra-Fisher of the Space Science Institute’s branch in Rancho Cucamonga, Calif. “Having two in seven years is even more rare. And two going through the same city is rarer still.”

That makes Carbondale the perfect spot to investigate how the sun’s atmosphere, or corona, looks different when solar activity is high versus low.

Every 11 years or so, the sun cycles from periods of high magnetic field activity to low activity and back again. The frequency of easy-to-see features — like sunspots on the sun’s visible surface, solar flares and the larger eruptions of coronal mass ejections — cycles, too. But it has been harder to trace what happens to the corona’s streamers, the long wispy tendrils that give the corona its crownlike appearance and originate from the magnetic field.
The corona is normally invisible from Earth, because the bright solar disk washes it out. Even space telescopes that are trained on the sun can’t see the inner part of the corona — they have to block some of it out for their own safety (SN Online: 8/11/17). So solar eclipses are the only time researchers can get a detailed view of what the inner corona, where the streamers are rooted, is up to.
Right now, the sun is in a period of exceptionally low activity. Even at the most recent peak in 2014, the sun’s number of flares and sunspots was pathetically wimpy (SN: 11/2/13, p. 22). During the Aug. 21 solar eclipse, solar activity will still be on the decline. But seven years from now during the 2024 eclipse, it will be on the upswing again, nearing its next peak.

Yanamandra-Fisher will be in Carbondale for both events. This year, she’s teaming up with a crowdsourced eclipse project called the Citizen Continental-America Telescope Eclipse experiment. Citizen CATE will place 68 identical telescopes along the eclipse’s path from Oregon to South Carolina.

As part of a series of experiments, Yanamandra-Fisher and her colleagues will measure the number, distribution and extent of streamers in the corona. Observations of the corona during eclipses going back as far as 1867 suggest that streamers vary with solar activity. During low activity, they tend to be more squat and concentrated closer to the sun’s equator. During high activity, they can get more stringy and spread out.

Scientists suspect that’s because as the sun ramps up its activity, its strengthening magnetic field lets the streamers stretch farther out into space. The sun’s equatorial magnetic field also splits to straddle the equator rather than encircle it. That allows streamers to spread toward the poles and occupy new space.

Although physicists have been studying the corona’s changes for 150 years, that’s still only a dozen or so solar cycles’ worth of data. There is plenty of room for new observations to help decipher the corona’s mysteries. And Yanamandra-Fisher’s group might be the first to collect data from the same point on Earth.

“This is pure science that can be done only during an eclipse,” Yanamandra-Fisher says. “I want to see how the corona changes.”

A new stretchy prosthetic could reduce the number of surgeries that children with leaking heart valves must undergo.

The device, a horseshoe-shaped implant that wraps around the base of a heart valve to keep it from leaking, is described online October 10 in Nature Biomedical Engineering. In adults, a rigid ring is used, but it can’t be implanted in children because it would constrict their natural heart growth. Instead, pediatric surgeons cinch their patients’ heart valves with stitches — which can break or pull through tissue as a child grows, requiring further surgery to repair.
It’s not uncommon for a child to require two to four of these follow-up procedures, says study coauthor Eric Feins, a cardiac surgeon at Boston Children’s Hospital and Harvard Medical School. Doctors in the United States perform over 1,000 pediatric heart valve repair surgeries each year.

“It’s quite invasive to do surgeries on a beating heart,” says coauthor Jeff Karp, a biomedical engineer at Brigham and Women’s Hospital in Boston. To decrease the need for these open-heart follow-up procedures, Karp and colleagues invented a new type of implant that stretches as its wearer grows. It’s made of a biodegradable polyester core covered by a mesh tube. The material of this outer sleeve is interwoven like a Chinese finger trap, so when heart valve tissue grows and tugs on the tube’s ends, it stretches. Over time, the core dissolves, and the growing tissue can pull the sleeve into a longer, thinner shape.
By tweaking an implant’s initial length and width, the core’s chemical makeup and the tightness of the sleeve’s braid, the researchers can fine-tune the stretchiness. This could allow developers to tailor each device to accommodate an individual patient’s expected growth rate.

“This is a brand new idea. I’ve never seen anything like it before,” says Gus Vlahakes, a cardiac surgeon at Massachusetts General Hospital in Boston, who was not involved in the study. “It’s a great concept.”
Karp and colleagues tested prototypes of the heart implant by inserting them into growing piglets. Twenty weeks after surgery, the implants had expanded as expected. The biomedical device company CryoLife, Inc. is now using the researchers’ design to build ring implants for further studies in lab animals, Karp says. “Clinical trials could start within a few years, if all goes well,” he says.

This growth-accommodating design may also be repurposed to make other kinds of pediatric implants. For instance, stretchable devices could supplant the stiff plates and staples that surgeons currently use to treat bone growth disorders. The researchers’ new implant model is “very generalizable,” Vlahakes says.

On Jupiter, lightning jerks and jolts a lot like it does on Earth.

Jovian lightning emits radio wave pulses that are typically separated by about one millisecond, researchers report May 23 in Nature Communications. The energetic prestissimo, the scientists say, is a sign that the gas giant’s lightning propagates in pulses, at a pace comparable to that of the bolts that cavort through our own planet’s thunderclouds. The similarities between the two world’s electrical phenomena could have implications for the search for alien life.
Arcs of lightning on both worlds appear to move somewhat like a winded hiker going up a mountain, pausing after each step to catch their breath, says Ivana Kolmašová, an atmospheric physicist at the Czech Academy of Sciences in Prague. “One step, another step, then another step … and so on.”

Here on Earth, lightning forms as turbulent winds within thunderclouds cause many ice crystals and water droplets to rub together, become charged and then move to opposite sides of the clouds, progressively generating static electrical charges. When the charges grow big enough to overcome the air’s ability to insulate them, electrons are released — the lightning takes its first step. From there, the surging electrons will repeatedly ionize the air and rush into it, lurching the bolt forward at an average of hundreds of thousands of meters per second.

Scientists have suggested that superbolts observed in Jovian clouds might also form by collisions between ice crystals and water droplets (SN: 8/5/20). But no one knew whether the alien bolts extended and branched in increments, as they do on Earth, or if they took some other form.

For the new study, Kolmašová and her colleagues used five years of radio wave data collected by NASA’s Juno spacecraft (SN: 12/15/22). Analyzing hundreds of thousands of radio wave snapshots, the team found radio wave emissions from Jovian lightning appeared to pulse at a rate comparable to that of Earth’s intracloud lightning — arcs of electricity that never strike ground.

If bolts extend through Jupiter’s water clouds at a similar velocity as they do in Earth’s clouds, then Jovian lightning might branch and extend in steps that are hundreds to thousands of meters long. That’s comparable in length to the jolted strides of Earth’s intracloud lightning, the researchers say.

“That’s a perfectly reasonable explanation,” says atmospheric physicist Richard Sonnenfeld of the New Mexico Institute of Mining and Technology in Socorro, who wasn’t involved in the study. Alternatively, he says, the signals could be produced as pulses of electrical current propagate back and forth along tendrils of lightning that have already formed, rather than from the stop-and-go advancements of a new bolt. On Earth, such currents cause some bolts to appear to flicker.

But stop and go seems like a sound interpretation, says atmospheric physicist Yoav Yair of Reichman University in Herzliya, Israel. Kolmašová and her colleagues “show that if you’re discharging a cloud … the physics remains basically the same [on Jupiter as on Earth], and the current will behave the same.”

If that universality is real, it could have implications for the search for life elsewhere. Experiments have shown that lightning strikes on Earth could have smelted some of the chemical ingredients needed to form the building blocks of life (SN: 3/16/21). If lightning is discharging in a similar way on alien worlds, Yair says, then it could be producing similar ingredients in those places too.

Brains are like sponges, slurping up new information. But sponges may also be a little bit like brains.

Sponges, which are humans’ very distant evolutionary relatives, don’t have nervous systems. But a detailed analysis of sponge cells turns up what might just be an echo of our own brains: cells called neuroids that crawl around the animal’s digestive chambers and send out messages, researchers report in the Nov. 5 Science.

The finding not only gives clues about the early evolution of more complicated nervous systems, but also raises many questions, says evolutionary biologist Thibaut Brunet of the Pasteur Institute in Paris, who wasn’t involved in the study. “This is just the beginning,” he says. “There’s a lot more to explore.”

The cells were lurking in Spongilla lacustris, a freshwater sponge that grows in lakes in the Northern Hemisphere. “We jokingly call it the Godzilla of sponges” because of the rhyme with Spongilla, say Jacob Musser, an evolutionary biologist in Detlev Arendt’s group at the European Molecular Biology Laboratory in Heidelberg, Germany.

Simple as they are, these sponges have a surprising amount of complexity, says Musser, who helped pry the sponges off a metal ferry dock using paint scrapers. “They’re such fascinating creatures.”
With sponges procured, Arendt, Musser and colleagues looked for genes active in individual sponge cells, ultimately arriving at a list of 18 distinct kinds of cells, some known and some unknown. Some of these cells used genes that are essential to more evolutionarily sophisticated nerve cells in other organisms for sending or receiving messages in the form of small blobs of cellular material called vesicles.

One such cell, called a neuroid, caught the scientists’ attention. After seeing that this cell was using those genes involved in nerve cell signaling, the researchers took a closer look. A view through a confocal microscope turned up an unexpected locale for the cells, Musser says. “We realized, ‘My God, they’re in the digestive chambers.’”

Large, circular digestive structures called choanocyte chambers help move water and nutrients through sponges’ canals, in part by the beating of hairlike cilia appendages (SN: 3/9/15). Neuroids were hovering around some of these cilia, the researchers found, and some of the cilia near neuroids were bent at angles that suggested that they were no longer moving.
The team suspects that these neuroids were sending signals to the cells charged with keeping the sponge fed, perhaps using vesicles to stop the movement of usually undulating cilia. If so, that would be a sophisticated level of control for an animal without a nervous system.

The finding suggests that sponges are using bits and bobs of communications systems that ultimately came together to work as brains of other animals. Understanding the details might provide clues to how nervous systems evolved. “What did animals have, before they had a nervous system?” Musser asks. “There aren’t many organisms that can tell us that. Sponges are one of them.”

Regenerating body parts is never easy. For instance, some lizards can grow back their tails, but these new appendages are pale imitations of the original. Now, genetically modified stem cells are helping geckos grow back better tails.

Tweaking and implanting embryonic stem cells on the tail stumps of mourning geckos (Lepidodactylus lugubris) allowed the reptiles to grow tails that are more like the original than ever before, researchers report October 14 in Nature Communications. These findings are a stepping-stone to developing regenerative therapies in humans that may one day treat hard-to-heal wounds.

A gecko’s tail is an extension of its spine — with the vertebrae to prove it. Regenerated tails, however, are simpler affairs. “It’s just a bunch of concentric tubes of fat, muscle and skin,” says Thomas Lozito, a biologist at the University of Southern California in Los Angeles.

That’s because stem cells in adult geckos produce a molecular signal that encourages the formation of cartilage in new tails, but not bone or nervous tissues (SN: 8/17/18). Lozito and his colleagues used embryonic stem cells, which can develop into a wider range of tissues than adult stem cells, modified them to ignore this signal and then implanted them on the tail stumps of geckos that had their tails surgically removed. The tails that grew from these modified stem cells had bonelike grooves in the cartilage and generated new neural tissue at the top of the tail.

These modified tails still lack a spinal cord, making them a far cry from the original. “We fixed one problem, but there are still many imperfections,” Lozito says. “We’re still on the hunt for the perfect tail.”