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Vol. LXV, No. 9
April 26, 2013
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Digest

Fat-Free See-Through Brain Bares All

Scientists can now study the brain’s finer workings, while preserving its 3-D structure and integrity of its circuitry and other biological machinery.
Scientists can now study the brain’s finer workings, while preserving its 3-D structure and integrity of its circuitry and other biological machinery.

Scientists can now study the brain’s finer workings, while preserving its 3-D structure and integrity of its circuitry and other biological machinery.

A breakthrough method, called CLARITY, developed by NIH-funded researchers, opens the intact postmortem brain to chemical, genetic and optical analyses that previously could only be performed using thin slices of tissue. By replacing fat that normally holds the brain’s working components in place with a clear gel, they made its normally opaque and impenetrable tissue see-through and permeable. This made it possible to image an intact mouse brain in high resolution down to the level of cells and molecules. The technique was even used successfully to study a human brain.

“CLARITY has the potential to unmask fine details of brains from people with brain disorders without losing larger-scale circuit perspective,” said NIH director Dr. Francis Collins, whose NIH Director’s Transformative Research Award Program helped to fund the work, along with a grant from the National Institute of Mental Health.

New Genetic Link Found Between Normal Fetal Growth, Cancer

Two NICHD researchers—Dr. Julian Lui and Dr. Jeffrey Baron—have discovered a new genetic link between the rapid growth of healthy fetuses and the uncontrolled cell division in cancer. The findings shed light on normal development and on the genetic underpinnings of common cancers. The work, conducted using mouse and human tissue, appeared in the Apr. 9 Proceedings of the National Academy of Sciences.

“We’ve long known that some of the genes that promote rapid growth in prenatal and early postnatal life become reactivated in cancer cells,” said Baron. “Now we’ve identified a molecular switch that appears to turn on some of these genes, taking us a step forward in understanding normal body growth and the abnormal growth in some types of cancer.”

Before birth, a team of more than 200 growth-promoting genes is highly active, fueling the fetus’ explosive growth. After birth, these genes are gradually switched off, apparently to slow body growth as we age and approach adult size. In cancer cells, some of these genes can be switched back on.

Researchers Create Next-Generation Alzheimer’s Model

A new genetically engineered lab rat that has the full array of brain changes associated with Alzheimer’s disease supports the idea that increases in a molecule called beta-amyloid in the brain causes the disease, according to an NIH-funded study published in the Journal of Neuroscience.

“We believe the rats will be an excellent, stringent pre-clinical model for testing experimental Alzheimer’s disease therapeutics,” said study senior author Dr. Terrence Town at the University of Southern California Keck School of Medicine.

Alzheimer’s is an age-related brain disorder that gradually destroys a person’s memory, thinking and the ability to carry out even the simplest tasks. Affecting at least 5.1 million Americans, the disease is the most common form of dementia in the United States. Pathological hallmarks of Alzheimer’s brains include abnormal levels of beta-amyloid protein that form amyloid plaques; tau proteins that clump together inside neurons and form neurofibrillary tangles; and neuron loss. Additionally, glial cells—which normally support, protect or nourish nerve cells—are overactivated in Alzheimer’s.

Promising Results Shown in Treating a Lymphoma in Young People

Patients with a type of cancer known as primary mediastinal B-cell lymphoma who received infusions of chemotherapy, but who did not have radiation therapy to an area of the thorax known as the mediastinum, had excellent outcomes, according to clinical trial results. Until now, most standard treatment approaches for patients with this type of lymphoma have included radiation therapy to the mediastinum. However, mediastinal radiation is associated with substantial long-term toxic side effects.

The results of this single-arm trial, which followed 51 patients for a period of up to 14 years, was conducted by researchers at the National Cancer Institute and appeared Apr. 11 in the New England Journal of Medicine.

Primary mediastinal B-cell lymphoma mainly affects people from their teenage years to their early 30s. Many patients are cured with a combination of chemotherapy and radiation therapy. However, even with this treatment, about 20 percent of patients see their disease progress.—compiled by Carla Garnett


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