Health Rounds: Dye turns mouse skin invisible, allows researchers to see inside

[September 07, 2024]  By Nancy Lapid

(Reuters) - Hello Health Rounds Readers! Sometimes science is just so cool. Today we feature a study that makes good on science envisioned by H.G. Wells over 100 years ago in "The Invisible Man". We also report on a new use of AI that can improve heart failure diagnosis in pregnant women, and the discovery of a new type of brain cell.

Light-absorbing dye turns mouse skin invisible

Applying a food-safe dye that absorbs light onto the skin of a mouse makes its skin transparent, allowing researchers to look into the blood vessels of the scalp, the movement of organs under the skin of the abdomen, and at working muscles, they reported on Thursday in Science.

The harmless process, which was reversible with a quick wash, may ultimately be useful in a wide range of medical diagnostics, the researchers said in a statement.

Injecting the dye - called tartrazine and commonly known as FD&C Yellow 5 - might lead to even deeper views into the body, they speculate.

Ordinarily, the body is not invisible because light bends and scatters differently as it passes through each of the different tissues and fluids.

When dissolved into water, tartrazine molecules are structured in a way that aligns with the light-bending ability of the skin, or its “refractive index.” The dye absorbs blue/purple light and allows red/orange light to travel through the tissue, resulting in transparency.

"Looking forward, this technology could make veins more visible for the drawing of blood, make laser-based tattoo removal more straightforward, or assist in the early detection and treatment of cancers,″ said Guosong Hong of Stanford University, who helped lead the research.

″For example, certain therapies use lasers to eliminate cancerous and precancerous cells, but are limited to areas near the skin’s surface. This technique may be able to improve that light penetration.”

A commentary published with the paper notes that H.G. Wells predicted this approach long ago in his novel The Invisible Man.

“The protagonist invents a serum that renders the cells in his body transparent by precisely controlling their refractive index to match that of the surrounding medium, air,” Christopher J. Rowlands and Jon Gorecki of Imperial College London wrote.

Now, 127 years later, the Stanford team reports "that biocompatible dyes make living tissues transparent by tuning the refractive index of the surrounding medium to match that of the cells.”

AI-enabled stethoscope improves pregnancy heart monitoring

An artificial intelligence-enabled digital stethoscope improves the identification of heart failure in pregnant women, according to data from a trial presented at the European Society of Cardiology Congress in London.

Heart failure during pregnancy often goes undetected because common symptoms such as shortness of breath, extreme fatigue and trouble breathing while lying down, are easily mistaken for typical pregnancy discomforts, they noted.

A stethoscope is seen in the pocket of a Nurse Consultant's uniform in this illustration. REUTERS/Hannah McKay/File Photo

The trial included nearly 1,200 women in Nigeria, which has the world’s highest rates of pregnancy-related heart failure.

Exams that included use of the AI-enabled digital stethoscope were 12-times more likely than traditional screening to flag heart pump weakness indicating a type of pregnancy-related heart failure called peripartum cardiomyopathy, according to results also published in Nature Medicine.

Recognizing this type of heart failure early is important to the mother's health and well-being, study leader Dr. Demilade Adedinsewo of the Mayo Clinic said in a statement.

"The symptoms of peripartum cardiomyopathy can get progressively worse as pregnancy advances, or more commonly following childbirth, and can endanger the mother's life," she said. "Severe cases may require intensive care, a mechanical heart pump, or sometimes a heart transplant, if not controlled with medical therapy."

Newly discovered brain cells may predict glioma outcome

Researchers have discovered a surprising new cell type in the human brain that may be linked with how patients are likely to fare with a certain type of brain tumor, according to a report in Cancer Cell.

The cells, found in brain tumors called gliomas and also in healthy brain tissue, fire electrical impulses called action potentials, researchers at Baylor College of Medicine in Houston found.

The discovery supports “the groundbreaking idea that neurons are not the only cells that can generate electric signals in the brain,” they said in a statement.

“We have known for some time now that tumor cells and neurons interact directly,” study coauthor Dr. Rachel Curry said in a statement. “But one question that always lingered in my mind was, ‘Are cancer cells electrically active?’"

Studying human brain cells obtained from patients undergoing brain surgery, the researchers found the newly identified cells are hybrids, with features of neurons and of glial cells, which hold neurons in place and help them function. Gliomas are tumors of glial tissue.

“We had never seen anything like this in the mammalian brain before,” study coauthor Dr. Qianqian Ma said in a statement.

Much more work is needed to determine the role of these hybrid cells in the brain, but the findings suggest that the proportion of them in gliomas may have a prognostic value.

“The data shows that the more of these spiking hybrid glioma cells a patient has, the better the survival outcome,” coauthor Dr. Ganesh Rao said in a statement. “This information is of great value to patients and their doctors.”

(Reporting by Nancy Lapid; editing by Bill Berkrot)

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