Links for Keyword: Neurotoxins

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By SHARON LERNER IN the fall, I began to research an article that I gave the working title “The Last Days of Chlorpyrifos.” A widely used pesticide, chlorpyrifos affects humans as well as the bugs it kills. Back in the halcyon days before the election, the optimism of the title seemed warranted. After years of study, the Environmental Protection Agency had announced in October 2015 that it could no longer vouch for the safety of chlorpyrifos on food. The agency had acknowledged for decades that chlorpyrifos can cause acute poisoning and in the early 2000s it had prohibited its use in most home products and reduced the amounts that could be used on some crops. But the 2015 announcement stemmed from the agency’s recognition of mounting evidence that prenatal exposure to chlorpyrifos could have lasting effects on children’s brains. Though the process of re-evaluating the safety of the pesticide had stretched on for years, at long last, chlorpyrifos seemed to be going down. Another report was expected to provide all the ammunition necessary to stop its use on fruits and vegetables, and I was eager to document its demise. For a reporter who covers the environment, this was going to be the rare happy story. The election of President Trump has thrown that outcome — indeed, the fate of many of the E.P.A.’s public health protections — into question. On Monday, Mr. Trump signed an executive order requiring federal agencies to scrap two regulations for every one they institute on small businesses. In its first week, his administration suspended 30 environmental regulations issued under President Barack Obama. And Myron Ebell, who oversaw the agency’s transition team, suggested recently that the E.P.A.’s staff may soon be reduced by as much as two-thirds. How will the agency’s mission “to protect human health and the environment” fare under this assault? What happens with chlorpyrifos may be our best indication. “I think it’ll be a very early test of their commitment to environmental protection,” Jim Jones, who oversaw the evaluation of chlorpyrifos as the E.P.A.’s assistant administrator for chemical safety and pollution prevention, told me, not long after he stepped down on Inauguration Day. © 2017 The New York Times Company

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 4: Development of the Brain
Link ID: 23190 - Posted: 02.06.2017

Air pollution is sending tiny magnetic particles into your brain

By Clare Wilson Traffic fumes go to your head. Tiny specks of metal in exhaust gases seem to fly up our noses and travel into our brains, where they may contribute to Alzheimer’s disease. Iron nanoparticles were already known to be present in the brain – but they were thought to come from the iron naturally found in our bodies, derived from food. Now a closer look at their structure suggests the particles mostly come from air pollution sources, like traffic fumes and coal burning. The findings are a smoking gun, says Barbara Maher of Lancaster University in the UK. Iron is present harmlessly in our bodies in different forms, as it is part of many biological molecules. But the form known as magnetite, or iron oxide, which is highly reactive and magnetic, has been implicated in Alzheimer’s disease. Maher’s team looked at the brains of 37 people who had lived either in Manchester in the UK or Mexico City. All contained millions of magnetite particles per gram of brain tissue, detected by measuring how magnetic the brain tissue was. The surprise came when the team used electron microscopes to take a close look at particles in the front part of the brains of six people. Round particles of magnetite outnumbered angular magnetite crystals by about one hundred to one. Crystal forms are more likely to have a natural source – such as iron that has come out of the body’s cells. But round particles normally come from melting iron at high temperatures, which happens when fuel is burned. © Copyright Reed Business Information Ltd.

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 22632 - Posted: 09.06.2016

Lead Levels Are Forcing More Than 1,000 Indiana Residents To Relocate

Merrit Kennedy More than 1,000 residents of a public housing complex in East Chicago, Ind., are now forced to relocate because of dangerously high lead levels in the area's soil. The West Calumet Housing Complex, which houses primarily low-income families, lies on the site of a former lead smelting company, as member station WBEZ reported. In July, the Environmental Protection Agency reported high lead levels in the soil in parts of the complex and notified the residents. The EPA advised parents to stop their kids from playing in the dirt, "to wash their children's toys regularly and to wash children's hands after they play outside." As WBEZ reported, the samples showed lead levels "three times higher than the federal safety standards and in some places even higher, much higher." After that, East Chicago Mayor Anthony Copeland "ordered the removal of 1,200 residents from the West Calumet housing project for safety concerns," according to the member station. The residents have now been informed that the 346-unit complex is set to be demolished. "Residents have been provided vouchers for temporary hotel living until their homes are done being cleaned. The residents will return to their homes for a few more months until vouchers for permanent housing are made available by the U.S. Department of Housing and Urban Development." © 2016 npr

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 22619 - Posted: 09.01.2016

What Is Chemo-Brain?

by Graham McDougall, Jr., behavioral scientist at U. of Alabama Chemo brain is a mental cloudiness reported by about 30 percent of cancer patients who receive chemotherapy. Symptoms typically include impairments in attention, concentration, executive function, memory and visuospatial skills. Since the 1990s researchers have tried to understand this phenomenon, particularly in breast cancer patients. But the exact cause of chemo brain remains unclear. Some studies indicate that chemotherapy may trigger a variety of related neurological symptoms. One study, which examined the effects of chemotherapy in 42 breast cancer patients who underwent a neuropsychological evaluation before and after treatment, found that almost three times more patients displayed signs of cognitive dysfunction after treatment as compared with before (21 versus 61 percent). A 2012 review of 17 studies considering 807 breast cancer patients found that cognitive changes after chemotherapy were pervasive. Other research indicates that the degree of mental fogginess that a patient experiences may be directly related to how much chemotherapy that person receives: higher doses lead to greater dysfunction. There are several possible mechanisms to explain the cognitive changes associated with chemotherapy treatments. The drugs may have direct neurotoxic effects on the brain or may indirectly trigger immunological responses that may cause an inflammatory reaction in the brain. Chemotherapy, however, is not the only possible culprit. Research also shows that cancer itself may cause changes to the brain. In addition, it is possible that the observed cognitive decline may simply be part of the natural aging process, especially considering that many cancer patients are older than 50 years. © 2016 Scientific American,

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 21820 - Posted: 01.26.2016

Desert Rats Finding Meals Less Palatable

By SINDYA N. BHANOO Climate change may affect wood rats in the Mojave Desert in a most unusual way. A new study finds that warmer weather reduces their ability to tolerate toxins in the creosote bush, which they rely on for sustenance. The consequences may be dire for the wood rats. “There’s not much more they can eat out there,” said Patrice Kurnath, a biologist at the University of Utah and one of the study’s authors. She and her colleagues reported their findings in Proceedings of the Royal Society B: Biological Sciences. The leaves of the creosote bush contain a resin full of toxic compounds. They are known to cause kidney cysts and liver failure in laboratory rats. Wild wood rats, however, generally tolerate the poisons. Ms. Kurnath and her colleagues monitored the wood rats as they ate the leaves in warmer temperatures — around 83 degrees Fahrenheit. Although highs in the Mojave can reach the 80s and 90s during the summer, much of the year is cooler. The rats became less tolerant of the toxins and began to lose weight. The reason may have to do with how the liver functions in warmer weather, Ms. Kurnath said. The liver is the body’s primary detoxifying organ. When a mammalian liver is active, it increases internal body temperature. “In warmer weather, maybe you’re not producing huge amounts of heat and you’re not breaking down the toxins,” Ms. Kurnath said. © 2016 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21817 - Posted: 01.25.2016

You Won’t Think the Platypus Is So Cute if You Feel the Excruciating Pain of Its Venom

By Megan Cartwright Don’t pet the platypus. I know it’s tempting: Given the chance, I’d want to stroke their thick brown fur, tickle those big webbed feet, and pat that funny duck bill. And why not? What harm could come from this cute, egg-laying mammal from eastern Australia? Plenty. As someone who doesn’t enjoy “long lasting excruciating pain that cannot be relieved with conventional painkillers,” I’d really regret petting a platypus. Especially a male platypus, in late winter, when there’s only one thing on his mind and, even worse, something nasty on his feet. When British biologist Sir Everard Home got ahold of some platypus specimens in 1801, he told his fellow nerds at the Royal Society how the male specimen had a half-inch long “strong crooked spur” on the heel of each rear foot. The female, however, was spur-free. Home suggested that it “is probably by means of these spurs or hooks, that the female is kept from withdrawing herself in the act of copulation.” A very reasonable suggestion. But a wrong one. To be fair to Home, he could only study dead platypuses. If Home could have spent a year hanging out with living platypuses in their river homes, he would’ve seen that this “shy, semi-aquatic, mainly nocturnal” mammal is mostly interested in hunting on the river bottom for delicious insect larvae, crayfish, and shrimp. In other words, the platypus is usually an eater, not a lover. © 2014 The Slate Group

Pollution May Age the Brain

By Nicholas Bakalar Exposure to air pollution may hasten brain aging, a new study has found. Researchers studied 1,403 women without dementia who were initially enrolled in a large health study from 1996 to 1998. They measured their brain volume with M.R.I. scans in 2005 and 2006, when the women were 71 to 89 years old. Using residential histories and air pollution data, they estimated their exposure to air pollution from 1999 to 2006. They used data recorded at monitoring sites on exposure to PM 2.5 — tiny particulate matter that easily penetrates the lungs. Each increase of 3.49 micrograms per cubic centimeter cumulative exposure to pollutants was associated with a 6.23 cubic centimeter decrease in white matter, the equivalent of one to two years of brain aging. The association remained after adjusting for many variables, including age, smoking, physical activity, blood pressure, body mass index, education and income. Previous studies have shown that air pollution can cause inflammation and damage to the vascular system, but this study, in The Annals of Neurology, showed damage to the brain itself. “This tells us that the damage air pollution can impart goes beyond the circulatory system,” said the lead author, Dr. Jiu-Chiuan Chen, an associate professor of preventive medicine at the Keck School of Medicine at the University of Southern California. “Particles in the ambient air are an environmental neurotoxin to the aging brain.” © 2015 The New York Times Company

Insulin-infused venom helps cone snails net prey

By David Shultz The most venomous animal on the planet isn’t a snake, a spider, or a scorpion; it’s a snail—a cone snail, to be precise. The Conus genus boasts a large variety of marine snails that have adopted an equally diverse assortment of venoms. Online today in the Proceedings of the National Academy of Sciences, researchers report an especially interesting addition to the animals’ arsenal: insulin. According to the paper, this marks the first time insulin has been discovered as a component of venom. Not all cone snails incorporate insulin into their venom cocktail, wonderfully known as nirvana cabal; the hormone was found only in a subset of the animals that hunt with a netting strategy that relies on snaring fish in their large, gaping mouthparts. Unlike the feeding tactics of some cone snails that hunt using speedy venom-tipped “harpoons,” the mouth-netting strategy is a rather slow process. For it to work, the fish either needs to be very unaware of its surroundings or chemically sedated. Scientists speculate that it’s the insulin that provides such sedation. Snails like Conus geographus (seen above) actually produce multiple variants of the hormone, some of which, like one called Con-Ins G1, are more similar to fish insulin than snail varieties. Con-Ins G1 isn’t an exact match of fish insulin though; it’s a stripped-down version that the team suspects may be missing bits that would let fish detect the overdose and respond. If they’re correct, the snail’s venom may yield insight into the nuances of how insulin is regulated that may extend to humans. © 2015 American Association for the Advancement of Science

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 8: Hormones and Sex
Link ID: 20501 - Posted: 01.21.2015

Mold may mean bad news for the brain

By Bethany Brookshire WASHINGTON – Moldy houses are hard on the lungs, and new results in mice suggest that they could also be bad for the brain. Inhaling mold spores made mice anxious and forgetful, researchers reported November 15 at the annual meeting of the Society for Neuroscience. Cheryl Harding, a psychologist at the City University of New York, and colleagues dripped low doses of spores from the toxic mold Stachybotrys into mouse noses three times per week. After three weeks, the mice didn’t look sick. But they had trouble remembering a fearful place. The mice were also more anxious than normal counterparts. The anxiety and memory deficits went along with decreases in new brain cells in the hippocampus — a part of the brain that plays a role in memory — compared with control mice. Harding and colleagues also found that the behaviors linked to increased inflammatory proteins in the hippocampus. Exposure to mold’s toxins and structural proteins may trigger an immune response in the brain. The findings, Harding says, may help explain some of the conditions that people living in moldy buildings complain about, such as anxiety and cognitive problems. C. Harding et al. Mold inhalation, brain inflammation, and behavioral dysfunction. Society for Neuroscience Meeting, Washington, DC, November 15, 2014. © Society for Science & the Public 2000 - 2014.

Related chapters from BN: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 20323 - Posted: 11.18.2014

Algal virus found in humans, slows brain activity

By Elizabeth Pennisi It’s not such a stretch to think that humans can catch the Ebola virus from monkeys and the flu virus from pigs. After all, they are all mammals with fundamentally similar physiologies. But now researchers have discovered that even a virus found in the lowly algae can make mammals its home. The invader doesn’t make people or mice sick, but it does seem to slow specific brain activities. The virus, called ATCV-1, showed up in human brain tissue several years ago, but at the time researchers could not be sure whether it had entered the tissue before or after the people died. Then, it showed up again in a survey of microbes and viruses in the throats of people with psychiatric disease. Pediatric infectious disease expert Robert Yolken from Johns Hopkins University School of Medicine in Baltimore, Maryland, and his colleagues were trying to see if pathogens play a role in these conditions. At first, they didn't know what ATCV-1 was, but a database search revealed its identity as a virus that typically infects a species of green algae found in lakes and rivers. The researchers wanted to find out if the virus was in healthy people as well as sick people. They checked for it in 92 healthy people participating in a study of cognitive function and found it in 43% of them. What’s more, those infected with the virus performed 10% worse than uninfected people on tests requiring visual processing. They were slower in drawing a line connecting a sequence of numbers randomly placed on a page, for example. And they seemed to have shorter attention spans, the researchers report online today in the Proceedings of the National Academy of Sciences. The effects were modest, but significant. © 2014 American Association for the Advancement of Science

Nanoparticles may harm the brain

By Jules Wellinghoff A simple change in electric charge may make the difference between someone getting the medicine they need and a trip to the emergency room—at least if a new study bears out. Researchers investigating the toxicity of particles designed to ferry drugs inside the body have found that carriers with a positive charge on their surface appear to cause damage if they reach the brain. These particles, called micelles, are one type of a class of materials known as nanoparticles. By varying properties such as charge, composition, and attached surface molecules, researchers can design nanoparticles to deliver medicine to specific body regions and cell types—and even to carry medicine into cells. This ability allows drugs to directly target locations they would otherwise be unable to, such as the heart of tumors. Researchers are also looking at nanoparticles as a way to transport drugs across the blood-brain barrier, a wall of tightly connected cells that keeps most medication out of the brain. Just how safe nanoparticles in the brain are, however, remains unclear. So Kristina Bram Knudsen, a toxicologist at the National Research Centre for the Working Environment in Copenhagen, and colleagues tested two types of micelles, which were made from different polymers that gave the micelles either a positive or negative surface charge. They injected both versions, empty of drugs, into the brains of rats, and 1 week later they checked for damage. Three out of the five rats injected with the positively charged micelles developed brain lesions. The rats injected with the negatively charged micelles or a saline control solution did not suffer any observable harm from the injections, the team will report in an upcoming issue of Nanotoxicology. © 2014 American Association for the Advancement of Science

Caffeine overdose killed high school senior, coroner finds

A toxic caffeine level was found in the system of a high school student who died unexpectedly, says a U.S. coroner who warns young people need to be educated about the dangers of taking the potent powder that is sold online. Logan Stiner, 18, was found dead at his family’s home in May. Steiner was an excellent student and a healthy young man who didn’t do drugs, Dr. Stephen Evans, a coroner in Lorain County, Ohio, said Monday. "We sent his blood out for levels, and [when] it came back it was a toxic level. Caffeine toxicity will do exactly what happened to him. It'll lead to things like cardiac arrhytmias and seizures," Evans said in an interview. Use of caffeine from coffee, tea and other beverages is so widespread that it is considered innocuous, but that’s not the case when it’s taken in an overdose amount. Powdered caffeine is sold in bulk over the internet. Problems can arise because adding a teaspoon of the caffeine powder to water is the equivalent of 30 cups of coffee. About one-sixteenth of a teaspoon of the powder is equal to about two cups of coffee. Evans said he recognizes that weightlifters will say Stiner should’ve taken the correct amount. "One-sixteenth of a teaspoon. You expect a kid to figure that out?" He suggested that regulators re-consider internet sales of a pound of powdered caffeine to young people. When Evans and his staff reviewed the pathology literature, they found 18 other cases of deaths in the U.S. from caffeine overdoses. Some were suicides and others were accidental, but he suspects the deaths are underreported since few pathologists investigating deaths from seizure and cardiac arrhytmia check caffeine levels. © CBC 2014

Lead in kids’ blood linked with behavioral and emotional problems

Emotional and behavioral problems show up even with low exposure to lead, and as blood lead levels increase in children, so do the problems, according to research funded by the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health. The results were published online June 30 in the journal JAMA Pediatrics. “This research focused on lower blood lead levels than most other studies and adds more evidence that there is no safe lead level,” explained NIEHS Health Scientist Administrator Kimberly Gray, Ph.D. “It is important to continue to study lead exposure in children around the world, and to fully understand short-term and long-term behavioral changes across developmental milestones. It is well-documented that lead exposure lowers the IQ of children.” Blood lead concentrations measured in more than 1,300 preschool children in China were associated with increased risk of behavioral and emotional problems, such as being anxious, depressed, or aggressive. The average blood lead level in the children was 6.4 micrograms per deciliter. While many studies to date have examined health effects at or above 10 micrograms per deciliter, this study focused on lower levels. The CDC now uses a reference level of 5 micrograms per deciliter, to identify children with blood lead levels that are much higher than normal, and recommends educating parents on reducing sources of lead in their environment and continued monitoring of blood lead levels.

The Toxins That Threaten Our Brains

James Hamblin Forty-one million IQ points. That’s what Dr. David Bellinger determined Americans have collectively forfeited as a result of exposure to lead, mercury, and organophosphate pesticides. In a 2012 paper published by the National Institutes of Health, Bellinger, a professor of neurology at Harvard Medical School, compared intelligence quotients among children whose mothers had been exposed to these neurotoxins while pregnant to those who had not. Bellinger calculates a total loss of 16.9 million IQ points due to exposure to organophosphates, the most common pesticides used in agriculture. Last month, more research brought concerns about chemical exposure and brain health to a heightened pitch. Philippe Grandjean, Bellinger’s Harvard colleague, and Philip Landrigan, dean for global health at Mount Sinai School of Medicine in Manhattan, announced to some controversy in the pages of a prestigious medical journal that a “silent pandemic” of toxins has been damaging the brains of unborn children. The experts named 12 chemicals—substances found in both the environment and everyday items like furniture and clothing—that they believed to be causing not just lower IQs but ADHD and autism spectrum disorder. Pesticides were among the toxins they identified. “So you recommend that pregnant women eat organic produce?” I asked Grandjean, a Danish-born researcher who travels around the world studying delayed effects of chemical exposure on children. “That’s what I advise people who ask me, yes. It’s the best way of preventing exposure to pesticides.” Grandjean estimates that there are about 45 organophosphate pesticides on the market, and “most have the potential to damage a developing nervous system.” © 2014 by The Atlantic Monthly Group.

ScienceShot: Breath So Bad It Could Save Your Life

For tobacco hornworms, bad breath might be the key to surviving the night. As their name suggests, these desert-dwelling caterpillars (larvae of the Manduca sexta moth) regularly chomp on nicotine-laced tobacco leaves. Scientists observed that caterpillars feeding on genetically modified, nicotine-free tobacco plants were more likely to disappear during the night than those chowing down on regular tobacco, leading them to suspect that the hornworms might be repurposing the toxic chemical to defend themselves against nocturnal predators like wolf spiders (Camptocosa parallela, pictured above feasting on a larva). The researchers investigated a gene called CYP6B46, which is active in the hornworm’s gut. Turning the gene off resulted in higher nicotine levels in the hornworms’ poop, suggesting that the gene helps the larvae avoid excreting the chemical by pumping it out of their guts and into their blood. The caterpillars had to be exuding the toxic nicotine somehow, so the scientists gave them an insect version of a breathalyzer test and discovered that they breathe it out with every exhale, the team reports online today in the Proceedings of the National Academy of Sciences. This “toxic halitosis” repelled wolf spiders, which actually flee from caterpillars with nicotine on their breath, as you can see in this video. Still, bad breath is no guarantee of a long life: It didn’t deter some of the hornworms’ other predators, including big-eyed bugs and antlion larvae. © 2013 American Association for the Advancement of Science

European Agency Warns of Risk to Humans in Pesticides Tied to Bee Deaths

By DANNY HAKIM LONDON — European food regulators said on Tuesday that a class of pesticides linked to the deaths of large numbers of honey bees might also harm human health, and they recommended that the European Commission further restrict their use. The commission, which requested the review, has already taken a tougher stance than regulators in other parts of the world against neonicotinoids, a relatively new nicotine-derived class of pesticide. Earlier this year, some were temporarily banned for use on many flowering crops in Europe that attract honey bees, an action that the pesticides’ makers are opposing in court. Now European Union regulators say the same class of pesticides “may affect the developing human nervous system” of children. They focused on two specific versions of the pesticide, acetamiprid and imidacloprid, saying they were safe to use only in smaller amounts than currently allowed. Imidacloprid was one of the pesticides placed under a two-year ban this year. The review was prompted by a Japanese study that raised similar concerns last year. Imidacloprid is one of the most popular insecticides, and is used in agricultural and consumer products. It was developed by Bayer, the German chemicals giant, and is the active ingredient in products like Bayer Advanced Fruit, Citrus & Vegetable Insect Control, which can be purchased at stores internationally, including Home Depot in the United States. Acetamiprid is sold by Nisso Chemical, a German branch of a Japanese company, though it was developed with Bayer’s help. It is used in consumer products like Ortho Flower, Fruit & Vegetable Insect Killer. The action by European regulators could affect the entire category of neonicotinoid pesticides, however. James Ramsay, a spokesman for the European Food Safety Authority, which conducted the review, said the agency was recommending a mandatory submission of studies related to developmental neurotoxicity “as part of the authorization process in the E.U.” © 2013 The New York Times Company

Museum Explores ‘The Power of Poison’

By HELENE STAPINSKI IN an office of the American Museum of Natural History, a team of scientists, artists and multimedia experts were discussing what had poisoned Skippy, a cute Jack Russell terrier that had keeled over sick in his virtual backyard. Was it the chocolate he found in the garbage can? Did a snake, or a black widow spider, bite him? Or was a poisonous cane toad to blame? Skippy is just one of many victims in the museum’s show, “The Power of Poison,” opening Nov. 16, to which the staff was busy applying finishing touches. Using iPads, visitors can examine the circumstances surrounding Skippy’s fictional poisoning and, controlling their experience individually, take a crack at solving the mystery. But because the museum is popular with small children, Skippy does not die. Instead, his animated eyes turn into Xs, he runs erratically around the yard, he drools and he vomits a bit. Eventually, though, Skippy rallies to full health. “We were not going to make this a scary show,” said the exhibit’s curator, Dr. Mark Siddall. “Instead you walk out saying, ‘Wow. That was cool.’ ” Dr. Siddall spent two hours enthusiastically discussing poison and its properties at the museum recently, walking through some of the show’s highlights. The exhibit, which takes a look at poison’s role in nature, myth, medicine and human history, examines killer caterpillars, zombie ants and deadly vipers. It also looks at the possible victims, like the heavily slumbering Snow White. Plus the age-old question of what killed Cleopatra. Was it an asp, or something else? And while we’re at it, was Napoleon really poisoned with arsenic? © 2013 The New York Times Company

Cassava and Mental Deficits

By DONALD G. McNEIL Jr. Konzo, a disease that comes from eating bitter cassava that has not been prepared properly — that is, soaked for days to break down its natural cyanide — has long been known to cripple children. The name, from the Yaka language of Central Africa, means “tied legs,” and victims stumble as if their knees were bound together. Now researchers have found that children who live where konzo is common but have no obvious physical symptoms may still have mental deficits from the illness. Cassava, also called manioc or tapioca, is eaten by 800 million people around the world and is a staple in Africa, where bitter varieties grow well even in arid regions. When properly soaked and dried, and especially when people have protein in their diet, bitter cassava is “pretty safe,” said Michael J. Boivin, a Michigan State psychiatry professor and lead author of a study published online by Pediatrics. “But in times of war, famine, displacement and hardship, people take shortcuts.” In the Democratic Republic of Congo, Dr. Boivin and colleagues gave tests of mental acuity and dexterity to three groups of children. Two groups were from a village near the Angolan border with regular konzo outbreaks: Half had leg problems; half did not but had cyanide in their urine. The third was from a village 125 miles away with a similar diet but little konzo because residents routinely detoxified cassava before cooking it. © 2013 The New York Times Company

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 14: Attention and Higher Cognition
Link ID: 18067 - Posted: 04.24.2013

Ricin is a potent but little-known bioterrorism agent

By David Brown, As a bioterrorism agent, ricin has the advantage of being easily made and highly potent. But there have been few fatal cases in the past 50 years, and there is little precise information about the substance’s effects on human beings. Ricin is not a microbe. It does not grow inside the body and can’t be passed from person to person. It is a toxin produced by the castor bean plant. When the beans are crushed for oil, the compound is left behind in the mashed material, of which more than a million tons is produced around the world each year. “It is a plant that grows wild throughout much of North America. You can buy the seeds online,” said Jennifer A. Oakes, a physician and expert in ricin poisoning at Albany Medical College. “It doesn’t take much to get a fatal dose. Somebody could do this in their house if they are motivated to.” Ricin’s best-known victim is Georgi Markov, a Bulgarian journalist who was stabbed by an umbrella on a London street in 1978. The umbrella’s tip injected a tiny metal capsule containing ricin into Markov’s leg. He died three days later. Apart from him, the only other ricin fatalities in the past 50 years have been a few suicides and accidental poisonings, usually after castor beans were eaten but at least once by injecting a crude extract. A person needs to take about 1,000 times as much ricin by mouth as by other routes to get a fatal dose. Unlike nerve agents and botulinum toxin, which disrupt nerve transmission and can cause death in minutes, ricin acts slowly. It stops the synthesis of proteins in cells, killing them over hours or days. A person dies of multi-organ failure as cells break down and fluid and essential electrolytes are lost. © 1996-2013 The Washington Post

“Chemo Brain”: Another Side Effect of Chemotherapy

By Lisa Raffensperger Among the many unpleasant side effects of chemotherapy treatment, researchers have just confirmed another: chemo brain. The term refers to the mental fog that chemotherapy patients report feeling during and after treatment. According to Jame Abraham, a professor at West Virginia University, about a quarter of patients undergoing chemotherapy have trouble focusing, processing numbers, and using short-term memory. A recent study points to the cause. The study relied on PET (positron emission tomography) brain scanning to examine brain blood flow, a marker for brain activity. Abraham and colleagues scanned the brains of 128 breast cancer patients before chemotherapy began and then 6 months later. The results showed a significant decrease in activity in regions responsible for memory, attention, planning and prioritizing. The findings aren’t immediately useful for treating or preventing the condition of chemo brain, but the hard and fast evidence may comfort those experiencing chemo-related forgetfulness. And luckily chemo brain is almost always temporary: patients’ mental processing generally returns to normal within a year or two after chemotherapy treatment ends.

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