Botulism toxin X: Time to update the textbooks, thanks to genomic sequencing

botulinum toxin X
Botulinum toxin X is the first new botulinum toxin to be identified since 1969. (Jason Wilson/Flickr)

Botulism is a rare, potentially fatal paralyzing illness. It’s the reason we shouldn’t feed infants honey and why we need to take care in consuming home-canned foods: they can potentially contain nerve-damaging toxins produced by Clostridium botulinum. Botulinum toxin is classified as one of the six most dangerous potential bioterrorism agents.

There are seven known types of botulinum toxin. Toxins A and B were first identified in 1919, and first purified in 1946 and 1947, respectively. (Both are also used medically.) Toxins C, D, E and F eventually followed. The last, toxin G, was identified in 1969 in soil bacteria in Argentina.

And that’s where it’s stood until now. But to truly defend against botulism, we need to know all the toxins made by the various C. botulinum strains, since each requires a separate antibody to neutralize it.

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Another microbiome perspective: The host holds the leash

Abstract depiction of the microbiome

Most scientists and clinicians accept that the human microbiome impacts a person’s nutrition, immune system function, physical health and perhaps even mental illness, but exactly how or why is not well understood. Now, taking an evolutionary approach, a Boston Children’s Hospital infectious disease researcher suggests the host may play a more active role in controlling the microbiome than previously appreciated.

“I think we need to re-evaluate the way in which we think about the microbiome,” says Seth Rakoff-Nahoum, MD, PhD, a physician-scientist at Boston Children’s in the Divisions of Infectious Diseases and Gastroenterology, whose perspective was published today in Nature.

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Pediatric heart surgeons eye sticky, stretchy, slug-inspired adhesive

Arion subfiscus, whose sticky mucus inspired the new surgical adhesive (H. Crisp/Wikimedia Commons)

It’s been a challenge to develop a surgical adhesive that sticks to wet surfaces and isn’t toxic. But it turns out a certain kind of slug is very good at secreting a sticky mucus that glues fast, apparently as a defense mechanism.

That provided the inspiration for a hydrogel “super” adhesive that could supplant surgical sutures, at least for some operations, and help medical devices stay in place. Researchers at the Wyss Institute for Biologically Inspired Engineering and Harvard’s School of Engineering and Applied Sciences (SEAS), led by David Mooney, PhD, report that the adhesive bound strongly to a variety of animal tissues, including skin, cartilage, artery, liver and heart.

Nikolay Vasilyev, MD, a coauthor on the paper, is interested in the adhesive’s potential for young patients with congenital heart disease. He is is a research scientist in Cardiac Surgery at Boston Children’s Hospital, and led cardiac studies in pig models. 

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Building emotional strength with Mighteor: Will’s story

MIghteor

Will, a 13-year-old from Wisconsin, lives with high-functioning Asperger’s and faces difficulties recognizing and managing his emotions. He doesn’t like to talk about emotions he perceives as negative, and becomes upset when he doesn’t meet the high standards he sets for himself. These oachhallenges have made it difficult for Will to thrive in social situations.

Karen immediately began researching strategies, as many as she could find, to help Will manage his emotions. She found a Social Thinking program, as well as ABA therapy, both of them important opportunities for Will to increase his “social batting average,” as Karen puts it.

However, Will soon became resistant to using the strategies offered by these programs. Cues to calm down through deep breathing, for example, tended to create more frustration and anger and did not decrease his swearing, frustration or oppositional behaviors. Despite his ongoing work with an ABA therapist and the Social Thinking program, his academics started to suffer and he sometimes had to leave the classroom. “He would miss class, and then miss homework, and it would circle out of control,” says Karen.

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Robot-enhanced neurosurgery for nimbler seizure mapping

implanting electrodes for seizure monitoring, with robotic assistance
Scellig Stone and Joseph Madsen in surgery with the robot.

Head shaved, a little boy rests on the operating table, deep under anesthesia. His parents have brought him to Boston Children’s Hospital in hopes of determining the cause of his seizures. Now, neurosurgeons Scellig Stone, MD, PhD, Joseph Madsen, MD, and their colleagues in the Epilepsy Center are performing a procedure designed to monitor seizure activity in the 3-year-old’s brain.

But as the team members crowd around the table, they’re not alone. With the push of a button, a large robotic arm rotates and lowers right next to the boy’s head, helping the physicians pinpoint the precise location to drill. “This is a real game-changer,” murmurs one of the clinicians observing the surgery. “It’s going to transform the way we practice.”

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From mice to humans: Genetic syndromes may be key to finding autism treatment

Boy and a mouse eye-to-eye
(Aliaksei Lasevich/stock.adobe.com)

A beautiful, happy little girl, Emma is the apple of her parents’ eyes and adored by her older sister. The only aspect of her day that is different from any other 6-month-old’s is the medicine she receives twice a day as part of a clinical trial for tuberous sclerosis complex (TSC).

Emma’s mother was just 20 weeks pregnant when she first heard the words “tuberous sclerosis,” a rare genetic condition that causes tumors to grow in various organs of the body. Prenatal imaging showed multiple benign tumors in Emma’s heart.

Emma displays no symptoms of her disease, except for random “spikes” on her electroencephalogram (EEG) picked up by her doctors at Boston Children’s Hospital. The medication she is receiving is part of the Preventing Epilepsy Using Vigabatrin in Infants with TSC (PREVeNT) trial. Her mother desperately hopes it is the active antiepileptic drug, vigabatrin, rather than placebo.

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Saving Vanessa part 2: Parent-driven science

DADA2 symptoms can be controlled with medications
Why did Vanessa’s mysterious rheumatologic condition cause her to have a stroke?

Two-year-old Vanessa had survived the unthinkable: two massive cerebral hemorrhages, nine days apart. Katherine Bell and her wife Nancy Mendoza felt immense relief at their daughter’s close call. But they wanted to know more. What had caused Vanessa’s strokes? Would there be more? Was the cause treatable?

The strokes were the culmination of a mysterious illness that had started with a rash. Because of high levels of inflammatory proteins in her blood, Vanessa’s rheumatologists, Pui Lee, MD PhD and Robert Sundel, MD, had given her a provisional, somewhat vague diagnosis of periodic fever syndrome.

“In rheumatology, we have to be comfortable with operating with a lot of unknowns,” Lee says.

But the strokes occurred despite three different anti-inflammatory treatments, which worked only temporarily. Bell, less comfortable with the unknowns, began searching the medical literature.

“It helped me feel calmer,” Bell says. “The more information I have, the less out of control I feel.”

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Training neurosurgeons in a rare hydrocephalus procedure, with a little help from Hollywood

ETV trainer

A 4-year-old has a progressively enlarging head and loss of developmental milestones: a clear case of hydrocephalus. He undergoes a minimally invasive endoscopic third ventriculostomy (ETV) to drain off the trapped cerebrospinal fluid.

This requires puncturing the floor of the brain’s third ventricle (fluid-filled cavity) with an endoscope — while avoiding a lethal tear in the basilar artery, which lies perilously close.

There are no good neurosurgical training models for this rare and scary operation.

“We semi-blindly poke a hole through the ventricle floor,” says Benjamin Warf, MD, director of Neonatal and Congenital Anomaly Neurosurgery at Boston Children’s Hospital. “To make the technique safer and to be able to train more people, it would be very helpful to make that hole in a way that’s less anxiety-provoking.”

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Severe flu infections linked to underlying genetic variation

Flu virusesThe Center for Disease Control estimates that influenza virus–related illnesses account for more than 200,000 U.S. hospitalizations and 12,000 deaths annually. Young children, the elderly and people with respiratory, cardiac and other chronic health conditions are at particularly high risk for being hospitalized for influenza-related complications. Until now, there has not been a clear reason to explain why some individuals become severely ill from flu and not others.

New findings published in Nature Medicine, however, might change that.

“We’ve identified a genetic variant that we believe may put people at risk of getting life-threatening influenza infections,” says Adrienne Randolph, MD, MSc, a senior associate in pediatric critical care medicine at the Boston Children’s Hospital.

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Newly-discovered epigenetic mechanism switches off genes regulating embryonic and placental development

Artwork depicting DNA and the code of genes

A biological process known as genomic imprinting helps control early mammalian development by turning genes on and off as the embryo and placenta grow. Errors in genomic imprinting can cause severe disorders and profound developmental defects that lead to lifelong health problems, yet the mechanisms behind these critical gene-regulating processes — and the glitches that cause them to go awry — have not been well understood.

Now, scientists at Harvard Medical School (HMS) and Boston Children’s Hospital have identified a mechanism that regulates the imprinting of multiple genes, including some of those critical to placental growth during early embryonic development in mice. The results were reported yesterday in Nature.

“A gene that is turned off by epigenetic modifications can be turned on much more easily than a gene that is mutated or missing can be fixed,” said Yi Zhang, PhD, a senior investigator in the Boston Children’s Program in Molecular and Cellular Medicine, a professor of pediatrics at HMS and a Howard Hughes Medical Institute investigator. “Our discovery sheds new light on a fundamental biological mechanism and can lay the groundwork for therapeutic advances.”

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