Newswise — During the COVID-19 pandemic, Johns Hopkins Medicine Media Relations is focused on disseminating current, accurate and useful information to the public via the media. As part of that effort, we are distributing our “COVID-19 Tip Sheet: Story Ideas from Johns Hopkins” every Tuesday throughout the duration of the outbreak.
We also want you to continue having access to the latest Johns Hopkins Medicine research achievements and clinical advances, so we are issuing a second tip sheet every Thursday, covering topics not related to COVID-19 or the SARS-CoV-2 virus.
Stories associated with journal publications provide a link to the paper. Interviews with the researchers featured may be arranged by contacting the media representatives listed.
SOMETHING IN THE WATER: ENVIRONMENTAL POLLUTANT MAY BE MORE HAZARDOUS THAN PREVIOUSLY THOUGHT
Media Contact: Ayanna Tucker
Sometimes toxins, such as hazardous wastes and industrial byproducts, seep into groundwater, the source of our drinking water. One such pollutant is perchlorate, a chemical compound used in rocket fuels, fireworks, fertilizers and other materials. The compound is thought to contribute to health issues in humans such as hypothyroidism, the decreased production of hormones from the thyroid gland, which can impact development.
In a new study published May 25, 2020, in the journal Nature Structural & Molecular Biology, researchers at Johns Hopkins Medicine, Vanderbilt University and the University of California, Irvine, report on the mechanism that perchlorate uses to impact and damage normal functioning of the thyroid gland.
The findings, they say, suggest that an acceptable safe concentration of perchlorate in drinking water is 10 times less than previously thought.
The researchers focused on how perchlorate blocks a main route by which iodide, the negatively charged form of the element iodine, enters thyroid cells. Iodide helps the thyroid make hormones that are essential to the body’s regulation of metabolism, temperature and other important functions.
Thyroid cells control the incoming flow of iodide by using a protein channel called the sodium/iodide symporter, also known as the Na+/I- symporter or NIS. Like other cellular transport systems, a “lock-and-key” approach is used to move iodide, with NIS acting as the lock and sodium as the key. Sodium fits into NIS at two binding sites to unlock the channel, enabling iodide to pass through and accumulate inside a thyroid cell.
The team, led by L Mario Amzel, Ph.D., professor of biophysics and biophysical chemistry at the Johns Hopkins University School of Medicine, and Vanderbilt University researcher Nancy Carrasco, M.D., determined that perchlorate blocks the channel by latching onto the NIS protein and changing its shape. Less sodium binds to the misshaped channel, thereby significantly lowering the amount of iodide that can be moved inside thyroid cells.
The researchers studied how varying concentrations of perchlorate affects iodide transport by first growing thyroid cells that expressed the gene SLC5A5, which encodes the instructions for building NIS channels. Next, perchlorate and radioactive iodine were placed outside of some of the cells and just radioactive iodine outside the others. Finally, the researchers tracked how much glowing iodide was allowed to enter the cells in both groups. They found that there was much less iodide inside thyroid cells treated with perchlorate than in untreated ones, even at very low concentrations of the chemical.
In May 2020, the U.S. Environmental Protection Agency (EPA) ruled not to place regulations on the amount of perchlorate that can be allowed in drinking water. The findings from the new study strongly suggest that this environmental pollutant is more hazardous than previously thought, raising serious concern about the decision.
“We hope that these findings will prompt the EPA to change its mind,” Amzel says.
PSYCHEDELIC DRUG PSILOCYBIN TAMPS DOWN BRAIN’S EGO CENTER
Media Contact: Vanessa McMains, Ph.D.
Perhaps no region of the brain is more fittingly named than the claustrum, taken from the Latin word for “hidden or shut away.” The claustrum is an extremely thin sheet of neurons deep within the cortex, yet it reaches out to every other region of the brain. Its true purpose remains “hidden away” as well, with researchers speculating about many functions. For example, Francis Crick of DNA-discovery fame believed that the claustrum is the seat of consciousness, responsible for awareness and sense of self.
What is known is that this region contains a large number of receptors targeted by psychedelic drugs such as LSD or psilocybin ¾ the hallucinogenic chemical found in certain mushrooms. To see what happens in the claustrum when people are on psychedelics, Johns Hopkins Medicine researchers compared the brain scans of people after they took psilocybin with their scans after taking a placebo.
The scans after psilocybin use showed that the claustrum was less active, meaning the area of the brain believed responsible for setting attention and switching tasks is turned down when on the drug. The researchers say that this ties in with what people report as typical effects of psychedelic drugs, including feelings of being connected to everything and reduced senses of self or ego.
“Our findings move us one step closer to understanding mechanisms underlying how psilocybin works in the brain,” says Frederick Barrett, Ph.D., assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine and a member of the school’s Center for Psychedelic and Consciousness Research. “This will hopefully enable us to better understand why it’s an effective therapy for certain psychiatric disorders, which might help us tailor therapies to help people more.”
Because of its deep-rooted location in the brain, the claustrum has been difficult to access and study. Last year, Barrett and his colleagues at the University of Maryland, Baltimore, developed a method to detect brain activity in the claustrum using functional magnetic resonance imaging (fMRI).
For this new study, the researchers used fMRI with 15 people and observed the claustrum brain region after the participants took either psilocybin or a placebo. They found that psilocybin reduced neural activity in the claustrum by 15% to 30%. This lowered activity also appeared to be associated with stronger subjective effects of the drug, such as emotional and mystical experiences. The researchers also found that psilocybin changed the way that the claustrum communicated with brain regions involved in hearing, attention, decision-making and remembering.
With the highly detailed imaging of the claustrum provided by fMRI, the researchers next hope to look at the mysterious brain region in people with certain psychiatric disorders such as depression and substance use disorder. The goal of these experiments will be to see what roles, if any, the claustrum plays in these conditions. The researchers also plan to observe the claustrum’s activity when under the influence of other psychedelics, such as salvinorin A, a hallucinogen derived from a Mexican plant.
YOUTH-INSPIRED PROGRAM INCREASES BIKE HELMET USE BY URBAN CHILDREN
Media Contact: Waun’Shae Blount
To reduce the number of traumatic brain injuries in children, a team of health care professionals at the Johns Hopkins University School of Medicine and the Johns Hopkins Bloomberg School of Public Health is urging emergency room physicians to help ensure that youngsters are thoroughly educated on the proper use of bike helmets, especially in urban environments where most severe head injuries occur.
One way, they suggest, is through the use of a new educational program — including support materials and a video made with the ideas and insight of Baltimore, Maryland, youth — that the Johns Hopkins team pilot tested in 2017. The successful outcome of that trial is reported in the May 17, 2020, issue of Health Promotion Practice.
“For families in low income and minority communities, programs that inform about helmet safety measures is crucial,” says lead study author Leticia Ryan, M.D., M.P.H., associate professor of pediatrics and director of research in pediatric emergency medicine at the Johns Hopkins University School of Medicine. “Our youth-oriented and culturally tailored approach could be explored as a strategy to achieve that goal.”
In the United States, 26,000 of the 325,000 children treated each year in emergency rooms for bicycle-related injuries experienced a traumatic brain injury. The Johns Hopkins researchers say prevention programs are needed but that they must be designed to reach all groups, regardless of socioeconomic status.
For example, they recommend providing helmets to disadvantaged families during information sessions about their proper use. The team says another way to overcome social barriers to prevention is to use educational materials — such as the Baltimore video — developed with input from the target audience of young bicycle riders.
In their study conducted between September and December 2017, the researchers worked with 20 urban Baltimore parents and their children, ages 8 to 15 (average age of 9), who had ridden a bicycle within the previous six months. To start, the children completed a pre-intervention survey and watched the “You Make the Call” video where urban youth discuss the importance of wearing a helmet. The intervention program also included a free helmet, fitting instructions and a parent guidance document. The study ended with the children completing a post-intervention survey.
Prior research had shown that the highest injury rate from bicycle use without a helmet occurs in the 10- to 15-year age range, and that most bicyclist deaths occur in urban areas. In the Johns Hopkins study, 13 (65%) of the participants reported in the pre-intervention survey that they rode their bikes on a weekly basis; however, 16 (80%) said that they did not own a helmet or never wore a helmet.
In the post-intervention survey after one month, five out of the 20 children (25%) reported riding their bikes during the study period, and all said that they used a helmet. All 20 children reported that they intended to use a helmet as a result of the intervention program.
Based on the findings of their study, the researchers say there is a need to tailor specific bike-helmet safety interventions to the most impacted groups, including low-income families and minorities.