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Genetic Linkage

Two Views of Leeches, A Century Apart

Two genome sequences of the European medicinal leech Hirudo medicinalis have just been revealed in a pair of papers, and the unexpected complexity may translate into new anti-coagulant drugs.

 

Some quick leech factoids: Of the 650 species, about 20 percent live in the ocean, where they feed on fish. The longest leech known extends 18 inches. A leech has 32 distinct brains and the genome extends about 230 million base pairs of DNA. Leeches belong to the same phylum as the earthworms, Annelida.

 

A Long History

 

The animals practice "hematophagy" – literally "eating blood." A leech will gorge itself to five times its weight until, satiated, it drops off its victim. The jaws are strong enough to penetrate a hippo's hide. Leeches have been used medicinally in bloodletting for thousands of years.

 

To continue reading, go to DNA Science, where this post first appeared.

 

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How an Antibody Cocktail Against COVID-19 Channels the 3 Stooges – But is a Great Idea

"You imbecile!" bellowed Moe Howard as he stuck a finger up the nose of Curly. Moe the bully would often flick his hand across an unsuspecting face or deliver a two-pronged eye poke to distract from a simultaneous, more serious blow, elsewhere.

 

Moe, Larry, and Shemp/Curly/Joe were the various incarnations of The Three Stooges, the famed comedy team, with roots in vaudeville, who made films and TV shows from 1922 until 1970. Many of us growing up in the sixties loved them, while many of our parents didn't. The 2012 film didn't do the original three idiots justice.

 

An image of Moe poking Curly popped into my head while reading two new papers in Science that report teaming antibodies to tackle SARS-CoV-2, the virus behind COVID-19.

 

The papers describe the basis of two clinical trials that biotech company Regeneron is conducting to assess a pair of antibodies that work together, binding the viral spike protein where it contacts the human receptor (ACE2) and gains entry into our cells, but at different sites within the "receptor-binding domain." One antibody is a distractor of sorts, like Moe's finger-up-the-nose.

 

The key to the technology is in the coupling. "Our work inventing novel antibodies has shown that individual antibodies, no matter how good, are likely not enough against the devastating virus that causes COVID-19 and the ways it seeks to 'escape' being neutralized," said George D. Yancopoulos, MD, PhD, Co-Founder, President and Chief Scientific Officer at Regeneron.

 

An antibody cocktail – pitched as "antibody medicine" – provides short-term, passive immunity, as opposed to the lasting active immunity of a vaccine, in which the body learns to manufacture its own antibodies. The Chinese proverb "Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime" makes the distinction: an antibody cocktail is a fish, a vaccine the ability to fish. Both are needed desperately right now. Antibody protection would last weeks or months.

 

Viral Resistance is a Natural Consequence of Evolution

 

 

To continue reading, go to DNA Science, where this post first appeared.

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‘Humanized mice’: Chimeras fuel quest to treat chronic diseases, cancer and even COVID-19

Some medical conditions can't be ethically investigated in humans, so researchers are finding interesting ways to grow people parts in the bodies of other types of animals. Jian Feng and colleagues at the University at Buffalo recently engineered prenatal mice that have human cells in key parts of their anatomy. Their report appears in Science Advances.

 

The humanized mice may one day incubate human cells needed for treatments of chronic diseases like kidney failure and diabetes, and provide new and improved models of how the human body succumbs to various conditions, from cancer to degenerative conditions to COVID-19.

 

To continue reading, go to Genetic Literacy Project, where this post first appeared.

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Protests and the Pandemic: Will COVID-19 Resurge?

Events have collided in a way that even the most imaginative fiction writer couldn't have conjured up: a global assault by an enemy that no one can see, and a nearly-9-minute-long murder of a black man by a white police officer captured on video for the world to see.

 

At the protests that the killing of George Floyd triggered, responses as global as COVID-19, many people are wearing masks and distancing themselves as they march, kneel, or lie down chanting "I can't breathe." But some are not following public health recommendations. And many are shouting, as police hurl chemicals that make people cough. What will the consequences of the massive and necessary Black Lives Matter protests be on public health?

 

The mathematical models used to predict the next stages of the pandemic may factor in the expected – Memorial Day celebrations and phased reopenings. But they couldn't have foreseen the events of the past two and a half weeks. How can people in close proximity for extended periods of time, moving and outdoors but hollering and crying, even if masked, affect transmissibility of the coronavirus? That seems like too many variables to model, but some recent technical articles might provide some insight.

 

Mask Math

 

 

To continue reading, go to my blog DNA Science, where this post first appeared.

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Dr. Fauci Optimistic About COVID-19 Vaccine Progress

 

On June 2, JAMA (The Journal of the American Medical Association) held a Q+A for the media with Dr. Anthony Fauci, director of the NIAID, accessible here. JAMA Editor Dr. Howard Bauchner frequently interviews leaders in the quest to understand and combat COVID-19. The webinar series has been a huge help to the science journalism community.

 

Dr. Fauci was considerably more upbeat in early June than he was on a JAMA webinar March 23, soon after he was present for a White House press briefing at which more than 10 unmasked people standing close to each other addressed more than 10 journalists on matters of public health and the pandemic.

 

At that JAMA webinar, Dr. Fauci explained the vaccine timetable based on how things were done in the past, and predicted we'd have one in 12 to 18 months. He said, then, that there's "no vaccine in the immediate future, which tells us we need to rely on public health measures."

 

To continue reading, go to my blog DNA Science.

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The Fallacy of the “Make It So” Mentality to Rush a COVID-19 Vaccine

Taking a meatloaf out of the oven too soon is an inconvenience, easily corrected by shoving it back in until it's ready.

 

Marketing a vaccine for COVID-19 too soon could be a disaster, with massive, far-reaching consequences. But that's what the U.S. government's Operation Warp Speed might make happen, with the goal of having a vaccine ready for distribution by year's end.

 

The problem is that vaccines aren't "found" or "discovered," like pretty shells on a beach, and if you just look enough, you'll find one. Vaccines are invented, developed, and tested, tested, tested, and that takes time. Biological factors could even make a vaccine impossible.

 

Measures are already in place to speed things along.

 

The FDA is collapsing protocols normally conducted in tandem into overlapping or parallel designs. They're allowing clinical trials to begin sooner following preclinical (non-human animal and cell-based) studies, expediting formation of institutional review boards to speed set-up of clinical trials, shifting reviewers from non-COVID projects to COVID ones, and enrolling thousands of people into clinical trials rather than the typical hundreds.

 

But will these measures be enough to roll out a vaccine six months from now? I don't think so.

 

To continue reading, go to my blog, DNA Science, at Public Library of Science. 

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Microbiome Analysis of Ancient Feces

Sometimes it can be difficult to distinguish who left a pile of poop.

 

Humans who live in multi-cat or multi-canine households might run into this problem when trying to discover which diarrhea-stricken pet to haul off to the vet.

 

Similarly, a deposit of scat on a hiking trail can inspire vivid conversations on the origin of the feces. But an intrigued hiker without a phone or camera who wants to bring a friend back for a viewing may find the excrement dispersed beyond recognition from weather conditions and trampling. Only a DNA test might be able to identify the species of animal that left the deposit if contextual clues, like a nearby moose, aren't there.

 

CoproID

 

The microbial species found within excrement – the fecal microbiome – can reveal a lot about an animal.

 

To continue reading, go to my blog DNA Science, at Public Library of Science. 

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Will the COVID-19 Pandemic End Like War of the Worlds or Logan’s Run?

In moments when I am not obsessively reading technical reports on COVID-19, my mind drifts to science fiction plots involving invaders. Do these films offer clues to how we can defeat the novel coronavirus SARS-CoV-2?

 

With the government-ordered CDC guidance for reopening delayed, dumbed-down, cut by an order of magnitude, and ignored, we need help, from anywhere, in protecting the vulnerable while restoring some economic normalcy.

 

The space invaders of the classic depictions either succumb to slowly-emerging natural weaknesses or we blow them up. But the scariest sci-fi theme to me isn't about monsters or microbes at all.

 

In the film Logan's Run, people over age 30 sacrifice themselves to save resources for the others.

 

To continue reading, go to my DNA Science blog at Public Library of Science. 

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Meet the Cammalleri Sisters: How Did They Live to Be 106 and 113?

Recently in my endless email about COVID-19 popped up a new paper analyzing the health of two Italian sisters who lived to remarkably old ages.

 

"The Phenotypic Characterization of the Cammalleri Sisters, an Example of Exceptional Longevity," from Calogero Caruso M.D. of the University of Palermo, Italy, and colleagues, is published in Rejuvenation Research.

 

Filippa was a "semi-supercentenarian" of 106 years, born December 12, 1911 and who died July 6, 2018. Her sister Diega, born October 23, 1905 and who died June 15, 2019, was a supercentenarian, living until age 113. Among centenarians – those who see their 100th birthdays – only 1 in 1,000 makes it to 110. Only 27 supercentenarians are known in the world.

 

To continue reading, go to my DNA Science blog at Public Library of Science. 

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Rare Disease Families Cope With COVID

Families that have members with rare diseases may face challenging situations during the pandemic. They're experts in navigating complex medical situations, but they must now weigh the risks and benefits of taking a loved one with a complication from a rare disease to a hospital.

 

"We have experience living with uncertainty, for years or even decades. Many of us have experience with isolation, and medically fragile people have always needed to be careful of exposure to people with illnesses. And many of us haven't been able to do things other families do," said Albert Freedman, PhD, a clinical psychologist and caregiver for a 24-year-old son who has spinal muscular atrophy (SMA). He spoke at a webinar that the National Organization for Rare Disorders (NORD) convened March 31, "A Rare Response: Addressing the COVID 19 Pandemic."

 

To continue reading, go to my blog DNA Science, at Public Library of Science (PLOS). 

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