Tracing the start of COVID-19 in GA

At a time when COVID-19 appears to be receding in much of Georgia, it’s worth revisiting the start of the pandemic in early 2020. Emory virologist Anne Piantadosi and colleagues have a paper in Viral Evolution on the earliest SARS-CoV-2 genetic sequences detected in Georgia. Analyzing relationships between those virus sequences and samples from other states and countries can give us an idea about where the first COVID-19 infections in Georgia came from. We can draw Read more

Reddit as window into opioid withdrawal strategies

Drug abuse researchers are using the social media site Reddit as a window into the experiences of people living with opioid addiction. Abeed Sarker in Emory's Department of Biomedical Informatics has a paper in Clinical Toxicology focusing on the phenomenon of “precipitated withdrawal,” in collaboration with emergency medicine specialists from Penn, Rutgers and Mt Sinai. Precipitated withdrawal is a more intense form of withdrawal that can occur when someone who was using opioids starts medication-assisted treatment Read more

CROI: HIV cure report and ongoing research

The big news out of CROI (Conference on Retroviruses and Opportunistic Infections) was a report of a third person being cured of HIV infection, this time using umbilical cord blood for a hematopoetic stem cell transplant. Emory’s Carlos del Rio gave a nice overview of the achievement for NPR this morning. As del Rio explains, the field of HIV cure research took off over the last decade after Timothy Brown, known as “the Berlin patient,” Read more

biophysics

A new term in biophysics: force/time = “yank”

Biologists and biomedical engineers are proposing to define the term “yank” for changes in force over time, something that our muscles cause and nerves can sense and respond to. Their ideas were published on September 12 in Journal of Experimental Biology.

Expressed mathematically, acceleration is the derivative of speed or velocity with respect to time. The term for the time derivative of acceleration is “jerk,” and additional time derivatives after jerk are called “snap,” “crackle” and “pop.”

The corresponding term for force – in physics, force is measured in units of mass times acceleration – has never been defined, the researchers say.

Scientists that study sports often use the term “rate of force development”, a measure of explosive strength. Scientists who study gait and balance — in animals and humans — also often analyze how quickly forces on the body change. It could be useful in understanding spasticity, a common neuromuscular reflex impairment in multiple sclerosis, spinal cord injury, stroke and cerebral palsy.

“Understanding how reflexes and sensory signals from the muscles are affected by neurological disorders is how we ended up needing to define the rate change in force,” says Lena Ting, PhD, professor of rehabilitation medicine at Emory University School of Medicine and the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory. Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Strength tests for platelets

Bleeding disorders could one day be diagnosed by putting platelets through strength tests, researchers have proposed.

Biomedical engineers from Emory and Georgia Tech have devised a microfluidic testing ground where platelets can demonstrate their strength by squeezing two protein dots together. Imagine rows and rows of strength testing machines from a carnival, but very tiny. Platelets are capable of exerting forces that are several times larger, in relation to their size, in comparison with muscle cells.

After a blood clot forms, it contracts, promoting wound closure and restoration of normal blood flow. This process can be deficient in a variety of blood clotting disorders. Previously, it was difficult to measure individual platelet’s contributions to contraction, because clots’ various components got in the way.

The prototype diagnostic tools are described in Nature Materials.

platelet_strength_test

Top: platelets exert their strength. Bottom left: red = platelets, green = fibrinogen dots. Bottom right: size of actual device.

“We discovered that platelets from some patients with bleeding disorders are ‘wimpier’ than platelets from healthy people,” says Wilbur Lam, MD, PhD, assistant professor in the Department of Pediatrics at Emory University School of Medicine and in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. “Our device may function as a new physics-based method to test for bleeding disorders, complementary to current methods.”

The first author of the paper is instructor David Myers, PhD. Lam is also a physician in the Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta. Collaborators at North Carolina State University led by Ashley Brown, PhD, contributed to testing the device.

The scientists infer how strong or wimpy someone’s platelets are by measuring how far the protein dots move, taking a picture of the rows of dots, and then analyzing the picture on a computer. The dots are made of fibrinogen, a sticky protein that is the precursor for fibrin, which forms a mesh of insoluble strands in a blood clot.

In addition to detecting problems with platelet contraction in patients with known inherited disorders such as Wiskott Aldrich syndrome, Myers, Lam and colleagues could also see differences in some patients who had bleeding symptoms, but who performed normally on standard diagnostic tests. Read more

Posted on by Quinn Eastman in Heart, Uncategorized Leave a comment