Journal Digest

Family Meals Can Reduce Effects of Bullying

Spending some time together as a family, such as at a dinner table, may help protect adolescents from the negative effects of cyberbullying, reports a study in JAMA Pediatrics.

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The study, led by researchers at McGill University, surveyed more than 18,000 adolescents in Wisconsin to identify the risk of various mental health consequences following exposure to cyberbullying. About 18 percent of adolescents surveyed experienced some form of online bullying, and victims of cyberbullying showed increased risk for all 11 outcomes measured, which included internalizing problems (anxiety, depression, self-harm, suicidal ideation, and suicide attempt), externalizing problems (fighting and vandalism), and substance abuse (frequent alcohol use, binge drinking, prescription drug misuse, and abuse of over-the-counter drugs).

The researchers also found that these effects related more strongly to cyberbullying victims who had fewer family dinners together. Though the connection is only correlational, the authors noted that family dinners, or other shared family time, offer a period of communication and social support that is beneficial to adolescents’ mental health.

“Many adolescents use social media, and online harassment and abuse are difficult for parents and educators to monitor, so it is critical to identify protective factors for youth who are exposed to cyberbullying,” commented lead author Frank Elgar, Ph.D., of McGill’s Institute for Health and Social Policy.

Xenon Gas Impairs Reconsolidation of Fear Memories

The unwanted reactivation of negative memories in the form of flashbacks or nightmares is a key event in posttraumatic stress disorder (PTSD), and scientists are looking for ways to block such painful memories from surfacing. Now, researchers at McLean Hospital have found that a dose of xenon gas given right after a traumatic memory surfaces can help erase that memory. The study, published in PLoS One, analyzed xenon exposure in a rat model of fear conditioning, but the approach could hold promise for humans, since xenon is already used in anesthesia and imaging.

Rats exposed to xenon gas for an hour immediately after exhibiting a memory-triggered fear response (freezing in response to a tone) displayed a significantly reduced fear response in subsequent tests given 48 hours, 96 hours, or 18 days later. This reduction was not observed if the xenon was administered two hours after the traumatic memory surfaced, and xenon did not have any effect if given before any fearful memories surfaced. These results support the notion that xenon inhibits memory reconsolidation—a process in which reactivated memories temporarily become labile.

The researchers will continue probing xenon’s effects, such as testing whether lower doses and a shorter exposure time can also erase negative memories. Such data will be important if xenon therapy can progress to human studies.

Autoantibodies Identified in Patients With Narcolepsy

Many scientists believe narcolepsy has an autoimmune component, though attempts to pinpoint definitive autoantibodies have not been fruitful. A new study published in Proceedings of the National Academy of Sciences may have found a promising candidate, however.

The research team tested the sera of 89 narcolepsy patients along with that of 52 people with other sleep disorders and 137 healthy controls. They found that 27 percent of the narcolepsy samples exhibited distinct staining patterns when tested on slices of rat brain, which was a much higher proportion than the other two groups.

Purified antibodies taken from narcolepsy patients could induce sleep disturbances when injected into rats, whereas antibodies from healthy subjects could not, further supporting the presence of autoantibodies.

Further analysis of stained neurons identified the likely autoantigen as a short motif found on the peptides neuropeptide glutamic acid-isoleucine (NEI) and a-melanocyte-stimulating-hormone (aMSH). The exact effects of disrupted NEI/aMSH aren’t known, but the authors noted that these peptides were found in close proximity to neurons containing hypocretin, the neurotransmitter that regulates wakefulness, which is lacking in many cases of narcolepsy.

Stem Cells Reveal Signaling Patterns in Schizophrenia Neurons

Researchers at the University of California, San Diego, used induced pluripotent stem cell (iPSCs) technology to uncover some of the chemical changes occurring in the neurons of people with schizophrenia. The researchers created functional neurons from human iPSCs generated from the skin cells of both healthy individuals and schizophrenia patients and then triggered the neurons to release neurotransmitters using potassium chloride.

What they observed was that neurons derived from schizophrenia patients secreted significantly more dopamine, norepinephrine, and epinephrine, which are known as the catecholamine neurotransmitters since they are synthesized from the amino acid tyrosine.

In addition, many of the schizophrenia neurons were producing tyrosine hydroxylase, the enzyme that initiates the synthesis of this neurotransmitter family. These findings, published in Stem Cell Reports, suggest that people with schizophrenia may be preprogrammed to secrete more catecholamine neurotransmitters than normal.

The researchers believe that these iPSC-derived neurons could have many applications, including being able to evaluate the severity of someone’s disease, prescreen patients for drug responses, and even test the efficacy of new drugs. ■