Warren symposium follows legacy of geneticist giant

If we want to understand how the brain creates memories, and how genetic disorders distort the brain’s machinery, then the fragile X gene is an ideal place to start. That’s why the Stephen T. Warren Memorial Symposium, taking place November 28-29 at Emory, will be a significant event for those interested in neuroscience and genetics. Stephen T. Warren, 1953-2021 Warren, the founding chair of Emory’s Department of Human Genetics, led an international team that discovered Read more

Mutations in V-ATPase proton pump implicated in epilepsy syndrome

Why and how disrupting V-ATPase function leads to epilepsy, researchers are just starting to figure Read more

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

exposome

All your environmental chemicals belong in the exposome

Emory researchers recently described a “contact tracing” system for environmental chemical exposures, published in Nature Communications. The apparent metabolic breakdown products of common drugs — antidepressants, blood thinners and beta-blockers – can be detected in clinical samples. Many of those breakdown products are uncharted territory, in terms of chemical analysis, and the Emory researchers’ system will help them map it.

But what about all the environmental chemicals that triggers the carbon offset level that are out there, such as PCBs (polychlorinated biphenyls), once widely used in electrical infrastructure, and pesticides such as DDT? PCB exposure has been connected with increased rates of cancer and harm to wildlife.

Xin Hu, PhD

A companion paper from the same group, also in Nature Communications, focuses more on techniques for detecting those contaminants. It lays out a standard workflow for processing samples for large-scale studies of the human exposome – all the influences from the environment as well as foods, drugs and other domestic products.

“What we aimed for was a simple method that is affordable and can be adopted by any laboratory to study as many chemicals as possible,” says lead author Xin Hu, PhD, assistant professor of medicine at Emory University School of Medicine. “We know that most of the contaminants have a small effect size, which means large-scale studies on tens of thousands of people are needed to understand the health effect of those contaminants and their link to rare but devastating diseases, like cancer.  A simple analytical method will allow us to combine efforts from different laboratories and studies, and eventually measure tens of thousands of chemicals on tens of thousands of people.”

Part of what the researchers needed to do is to test and optimize methods for studying each type of environmental chemical, using a technique called GC-HRMS (gas chromatography-high resolution mass spectrometry). Previous studies on PCBs and DDT use that technique, but the Emory team wanted to develop a standard low-volume approach that would avoid multiple processing steps, which can lead to loss of material, variable recovery, and the potential for contamination.

The researchers used their approach to analyze samples from human plasma, lung, thyroid and stool. They also showed that they could identify new chemicals in clinical samples. An advantage of the new method over traditional approaches is that the database retains information of unidentified chemicals that can be readily accessed for future characterization, Hu says.

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Reading the blood: metabolomics

In the Star Trek series, Dr. McCoy could often instantly diagnose someone’s condition with the aid of his tricorder. Medicine on 21st century Earth has not advanced quite this far, but scientists’ ideas of how to use “metabolomics” are heading in this direction.

What is metabolomics? Just as genomics means reading the DNA in a person or organism, and assessing it and comparing it to others, metabolomics takes the same approach to all the substances produced as part of the body’s metabolism: watching what happens to food, drugs and chemicals we are exposed to in the environment.

This means dealing with a huge amount of information. Human genomes may be billions of letters (base pairs) in length, but at least there are only four choices of letter!

A recent article in Chemical & Engineering News explores this concept of the “exposome” and quotes Dean Jones. He and his colleagues recently described how they can use sophisticated analytical techniques to resolve thousands of substances in human plasma. Jones is the director of the Clinical Biomarkers Laboratory at Emory University School of Medicine. The paper is in the journal Analyst, published by the Royal Society of Chemistry.

Analytical techniques can discern more than 2500 metabolites from human plasma within 10 minutes

Using a drop of blood, within ten minutes the researchers can discern more than 2,500 substances in a reproducible way. One fascinating tidbit: when they compared the metabolic profiles for four healthy individuals, most of the “peaks” were common between individuals but 10 percent were unique.

The potential uses for this type of technology are staggering.

Jones reports he has been working with researchers at Yerkes National Primate Research Center to discern early signs of neurodegeneration in transgenic monkeys with Huntington’s disease. He has been collaborating with clinical nutrition specialist Tom Ziegler to examine how diet interacts with oxidative stress, and with lung biology to identify markers for fetal alcohol exposure in animal models.

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