Brain organoid model shows molecular signs of Alzheimer’s before birth

In a model of human fetal brain development, Emory researchers can see perturbations of epigenetic markers in cells derived from people with familial early-onset Alzheimer’s disease, which takes decades to appear. This suggests that in people who inherit mutations linked to early-onset Alzheimer’s, it would be possible to detect molecular changes in their brains before birth. The results were published in the journal Cell Reports. “The beauty of using organoids is that they allow us to Read more

The earliest spot for Alzheimer's blues

How the most common genetic risk factor in AD interacts with the earliest site of neurodegeneration Read more

Make ‘em fight: redirecting neutrophils in CF

Why do people with cystic fibrosis (CF) have such trouble with lung infections? The conventional view is that people with CF are at greater risk for lung infections because thick, sticky mucus builds up in their lungs, allowing bacteria to thrive. CF is caused by a mutation that affects the composition of the mucus. Rabindra Tirouvanziam, an immunologist at Emory, says a better question is: what type of cell is supposed to be fighting the Read more

Department of Rehabilitation Medicine

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

Hypoxia is bad, except when it’s good

Randy Trumbower and his colleagues in Emory’s Department of Rehabilitation Medicine recently published a study showing that “daily intermittent hypoxia,” combined with walking exercise, can help patients with incomplete spinal cord injury walk for longer times. What is it about being deprived of oxygen for short periods that has a positive effect?

This research was puzzling at first (at least to your correspondent) because “daily intermittent hypoxia” is a good description of the gasping and snorting interruptions of sleep apnea.

Sleep apnea is a very common condition that increases the risk of high blood pressure, diabetes, heart attack and stroke. On the other side of the coin, many endurance athletes have been harnessing the body’s ability to adapt to low oxygen levels — so-called altitude training — to increase their performance for years.

So we have an apparent clash: hypoxia is bad, except when it’s good. Looking closely, there are some critical differences between sleep apnea and therapeutic hypoxia. The dose makes the poison, right? Read more

Posted on by Quinn Eastman in Neuro Leave a comment