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Research at Mass General
Nanoparticles could point the way to more effective cancer treatments, plus researchers investigate why individuals with autism often avoid eye contact.
Nanoparticles, tiny molecules typically between 20 and 100 nanometers in size, are increasingly being used to transport drugs to a specific target in the body.
They’re small enough to carry drugs through the body and can protect the encapsulated drug from toxic substances in the bloodstream that are used in infusion chemotherapy. However, in clinical practice, delivering nanoencapsulated drugs into patients’ tumors has been challenging—tumor blood vessels are difficult to break through which limits the passage of any drugs from the bloodstream into tumor cells.
Miles Miller, PhD, of the Center for Systems Biology, and lead author of the study published in Science Translational Medicine, found that tumor-associated macrophages — immune cells found around tumors that are in charge of engulfing pathogens, foreign materials and dead cells — can help bring the drugs inside the tumor, if the tumors are treated with radiation prior to administering the drugs.
The radiation weakens the blood vessels within the tumor and increases the number of macrophages attracted to tumor blood vessels which, in turn, pick up the drug-laden nanoparticles and bring them into the tumor.
The sudden influx of microphages into the weakened walls of the blood vessels causes many of the vessels to burst, thus flooding the tumor cells with the nanoparticles and improving drug delivery by 600 percent.
“Most of the treatments and nanomedicines employed in this study are FDA approved for cancer treatment, so this combination treatment strategy could be tested in clinical trials relatively quickly,” said Miller.
Individuals with autism often find it difficult to look others in the eyes. Many say that maintaining eye contact is uncomfortable or stressful for them – some will even say that “it burns” – which suggests the root of this discomfort is neurological.
In a new study published in Nature Scientific Reports, Nouchine Hadjikhani, MD, PhD, Director of Neurolimbic Research in the Athinoula A. Martinos Center for Biomedical Imaging, and corresponding author, presented images of faces conveying different emotions to study subjects with and without autism and measured their brain activity via functional magnetic resonance imaging (fMRI).
When both groups were able to gaze at the images freely, there was no difference in subcortical activation.
When the test was changed to narrow the focus to the eyes, Hadjikhani observed overactivation of the subcortical system in participants with autism. Images of fearful faces prompted the most significant response. Their results support the idea that there is an imbalance between the brain's “excitatory” network, which reacts to stimulation, and inhibitory network, which calms it down.
The findings suggest that behavioral therapies that try to force individuals with autism to make eye contact could be counterproductive. A better approach may be to slowly introduce these individuals to eye contact so they can learn strategies for managing the accompanying sensations.
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