Concussions fewer in kids’ practices than in games

Young football players are at a low risk for getting a concussion in practice and similar to high-school and college football players in their incidence rate of concussions.

Anthony Kontos, faculty member in the Department of Orthopaedic Surgery at the School of Medicine and the study’s principal investigator, said: “This finding suggests that reducing contact-practice exposures in youth football, which some leagues have done recently, will likely have little effect on reducing concussion risk. Youth-football leagues should focus on awareness and education about concussion.” Kontos also is assistant research director for the UPMC sports medicine concussion program.

In the study, encompassing 468 players on 18 youth-football teams from suburban Pittsburgh and central Pennsylvania, the researchers found that practices were relatively concussion-free (0.24 incidents per 1,000 exposures). However, these youth players were 26 times more likely to suffer a concussion in a game (6.16 incidents per 1,000 exposures) than in practice. To the researchers, these data suggest that contact practices provide an appropriate, controlled environment to teach proper tackling techniques, which may decrease the incidence of concussions. Those techniques, focusing on shoulder instead of helmet contact, are being taught around USA Football and through other youth-football organizations across the United States.

The incidence rate of concussions in 8- to 12-year-old players — 1.76 per 1,000 game and practice exposures — proved comparable to the incidence rate previously reported for high-school and college players, the researchers found. The 0.24/1,000 rate in practices is slightly lower than found in high school and college.

Age played a factor. The 8- to 10-year-olds were almost three times less likely to suffer a concussion than 11- to 12-year-olds, with 0.93/1,000 exposures in games and practices among the younger group, compared to 2.53/1,000 in the older. The pre-teens sustained three times as many concussions despite participating in 10 percent more games and practices. The researchers added that maturation translates into bigger, stronger, faster athletes who engage in more contact than younger players.

Quarterback, running back and linebacker — the “skill” positions in youth football — absorbed almost all of the total concussions, 19 of 20 (95 percent). Rotating players to different positions may help to mitigate concussion risks, researchers said.

The researchers noted that more research is needed. Little is known about the potential for long-term effects from repetitive exposures to sub-concussive impacts that might occur in practices and games. Therefore, more scrutiny is warranted overall, to include more seasons, a wider sample size and older, middle-school players.

The research was funded by a $100,000 grant from NFL Charities and published in the Journal of Pediatrics.

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Self-regulation of boys lags in U.S., not Asia

A Pitt researcher has found a gender gap in behavior and self-control in American children, one that does not appear to exist in children in Asia.

In the United States, according to the study, girls have higher levels of self-regulation than boys. In China, South Korea and Taiwan, the study found no gender gap when researchers directly assessed the self-regulation of 3- to 6-year-olds. Self-regulation is defined as children’s ability to control their behavior and impulses, follow directions and persist in completing a task.

Shannon Wanless, lead author of the study and faculty member in the Department of Psychology in Education in the School of Education, said: “These findings suggest that although we often expect girls to be more self-regulated than boys, this may not be the case for Asian children.”

Although there were no gender differences in self-regulation when the children were assessed directly using a variety of school-readiness tasks in a quiet space, teachers in Asia perceived girls as performing better on self-regulation even when they and boys actually performed equally when assessed overall.

“Teachers are rating children’s behavior in the classroom environment, which has a lot of distractions and is very stimulating,” said Wanless. “It is possible that boys in the Asian countries were able to self-regulate as well as girls when they were in a quiet space (the direct assessment), but were not able to regulate themselves as well in a bustling classroom environment (teacher ratings).”

Wanless and co-authors at U.S. and Asian universities conducted assessments of 814 children in the United States, China, South Korea and Taiwan. Their study showed that U.S. girls had significantly higher self-regulation than boys, but there were no significant gender differences in any Asian societies. In addition, for both genders, directly assessed and teacher-rated self-regulation were related to many aspects of school readiness in all societies for girls and boys.

Wanless said this study paves the way for future research to explore why there is such a large gender gap in the United States and what can be learned from Asian schools.

“When we see differences in developmental patterns across countries it suggests that we might want to look at teaching and parenting practices in those countries and think about how they might apply in the United States,” she said.

The paper appeared online in Early Childhood Research Quarterly.

Funding was provided by the U.S. Department of State Fulbright Student Scholarship, the Ryoichi Sasakawa Young Leaders Fellowship Fund, the Oregon Sports Lottery, the Kappa Omicron Nu Honor Society, the National Institute of Child and Human Development and the National Science Foundation (NSF).

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Cancer findings presented

Depression in patients with advanced cancer, chemotherapy maintenance regimens in lung cancer and the progression of melanoma were among the topics presented by researchers from the University of Pittsburgh Cancer Institute (UPCI), partnering with the UPMC CancerCenter, at the annual meeting of the American Society of Clinical Oncology (ASCO) in June.

Pitt researchers Weijing Sun, School of Medicine faculty member and director of the GI Cancers Section of Hematology-Oncology, and Priya Rastogi, medicine faculty member, served on panels to discuss new findings. Sun spoke about bevacizumab in colorectal cancer and early response as an indicator of overall survival, while Rastogi discussed the latest findings in the HER2-positive neoadjuvant trials in breast cancer.

Other highlights included the following presentations:

• Drug therapies for metastatic melanoma: John Kirkwood, medicine faculty member and director of UPMC CancerCenter’s melanoma program, and colleagues were part of a multicenter, randomized phase II trial of GM-CSF plus ipilimumab versus ipi alone in metastatic melanoma.

• Depression linked to cancer survival: Jennifer Steel, faculty member in surgery and psychiatry and director of the Center for Excellence in Behavioral Medicine, presented findings of a study examining the mechanisms associated with the link between depression and increased risk of mortality in patients with advanced cancer.

In the study of 474 patients with advanced cancer, researchers found 47 percent of patients reported depressive symptoms in the clinical range, and the course of the depression was linked to their survival after adjusting for demographic and disease-specific factors. The biological mechanisms believed to link depression and mortality included pro-inflammatory cytokines, which were elevated in those patients with clinical levels of depression. Depressive symptoms both increased and decreased in relationship to the levels of the cytokines over time.

Preliminary evidence also suggested that depression was linked to an increase of a biomarker of inflammation near the tumor in a small sample of patients who underwent surgery. These biomarkers of inflammation in the serum and tumor microenvironment have been shown to be associated with tumor growth and development of metastases.

• Lung cancer treatments compared: Mark Socinski, medicine faculty member, presented findings of a team led by UPCI researchers who found in a phase III study of more than 900 patients with late-stage nonsquamous, non-small cell lung cancer that a regimen of pemetrexed, carboplatin and bevacizumab followed by maintenance pemetrexed and bevacizumab (Pem arm) did not improve overall survival rates compared with a regimen of paclitaxel, carboplatin and bevacizumab followed by maintenance bevacizumab (Pac arm).

Progression-free survival time, meaning the length of time that the disease did not get worse, was generally longer in the Pem arm, particularly for patients 70 and younger.

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Facebook mutual friends feature creates concerns

The mutual-friends feature on social networks such as Facebook, which displays users’ shared friendships, might not be so “friendly,” according to a study led by principal investigator James Joshi, faculty member in information assurance and security in the School of Information Sciences.

The study demonstrates that even though users can tailor their privacy settings, hackers still can find private information through mutual-friends features.

Together with Lei Jin, a PhD candidate in information sciences and former faculty member Mohd Anwar, now at North Carolina A&T State University, Joshi examined three different types of attacks on social network users using an offline Facebook dataset containing 63,731 users from the New Orleans regional network. This dataset, chosen because it was open to the public, also included more than a million friend links.

Using computer simulation programs, the researchers first demonstrated a “friend exposure” attack, exploring how many private friends of a specific target user an “attacker” could find. The attacks were tested on 10 randomly chosen user groups ranging between 500 and 5,000 individuals, as well as sample groups that were computer-generated based on shared interests across user profiles. The same process was used for the “distant neighbor exposure attack” through which the attacker’s goal was to identify private distant neighbors from the initial target. These distant neighbors indicate users that are friends of friends of the target user (two degrees of separation) or even friends of friends of friends of the target user (three degrees of separation).

Finally, the team initiated a “hybrid attack” in which an attacker tried to identify both the target’s private friends and distant neighbors.

They found that an attacker identified more than 60 percent of a target’s private friends in the “mutual-friend based attack.” Likewise, an attacker could find, on average, 67 percent of a target’s private distant neighbors by using 100 compromised user accounts.

“Being able to see mutual friends may allow one to find out important and private social connections of a targeted user,” said Joshi. “An attacker can infer such information as political affiliations or private information that could be socially embarrassing. More importantly, the information that’s gathered could be used, in combination with other background information about the targeted user, to create false identities that appear even more authentic than the actual user.”

Joshi cites the need for better privacy-protection settings to mitigate the problem — but those that can also be easily navigated by users.

The paper was published online in Computers & Security.

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Details of HIV’s inner coat point to new therapies

A study under senior author Peijun Zhang, faculty member in the Department of Structural Biology at the School of Medicine, has described the 4-million-atom structure of the HIV’s capsid, or protein shell. The findings could lead to new ways of fending off an often-changing virus that has been hard to conquer.

Scientists long have struggled to decipher how the HIV capsid shell is put together chemically. Said Zhang: “The capsid is critically important for HIV replication, so knowing its structure in detail could lead us to new drugs that can treat or prevent the infection. This approach has the potential to be a powerful alternative to our current HIV therapies, which work by targeting certain enzymes, but drug resistance is an enormous challenge due to the virus’s high mutation rate.”

Previous research has shown that the cone-shaped shell is composed of identical capsid proteins linked together in a complex lattice of about 200 hexamers and 12 pentamers, Zhang said. But the shell is non-uniform and asymmetrical; uncertainty remained about the exact number of proteins involved and how the hexagons of six protein subunits and pentagons of five subunits are joined. Standard structural biology methods to decipher the molecular architecture are insufficient because they rely on averaged data, collected on samples of pieces of the highly variable capsid to identify how these pieces tend to go together.

Instead, the team used a hybrid approach, taking data from cryo-electron microscopy at an 8-angstrom resolution (a hydrogen atom measures 0.25 angstrom) to uncover how the hexamers are connected and cryo-electron tomography of native HIV-1 cores, isolated from virions, to join the pieces of the puzzle. Collaborators at the University of Illinois then used their supercomputer to run simulations at the petascale, involving 1 quadrillion operations per second, that positioned 1,300 proteins into a whole that reflected the capsid’s known physical and structural characteristics.

The process revealed a three-helix bundle with critical molecular interactions at the seams of the capsid, areas that are necessary for the shell’s assembly and stability, which represent vulnerabilities in the protective coat of the viral genome.

“The capsid is very sensitive to mutation, so if we can disrupt those interfaces, we could interfere with capsid function,” Zhang said. “The capsid has to remain intact to protect the HIV genome and get it into the human cell, but once inside it has to come apart to release its content so that the virus can replicate. Developing drugs that cause capsid dysfunction by preventing its assembly or disassembly might stop the virus from reproducing.”

The project was funded by the National Institutes of Health (NIH) and NSF. Co-authors included Gongpu Zhao, Xin Meng, Jiying Ning, Jinwoo Ahn and Angela Gronenborn of Pitt, as well as researchers from Illinois/Urbana-Champaign, Vanderbilt and Central Florida-Orlando.

The research was published in the May 30 issue of Nature.

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Twitter may broadcast more, be less interactive

The social media site Twitter eventually may resemble a broadcast medium like television or radio, with users reading messages written by celebrities and corporations rather than writing their own “tweets” of up to 140 characters, suggests a new study coauthored by Andrew T. Stephen, Katz Fellow in Marketing in the Joseph M. Katz Graduate School of Business and College of Business Administration.

Stephen and his co-author from Columbia questioned what motivates people to post tweets. Are Twitter users motivated by broadcasting their thoughts and opinions or, rather, by their desire to increase their social status by accumulating followers?

Stephen and his colleague identified approximately 2,500 Twitter users who were being followed by a range of other Twitter users, numbering from 13 to more than 10,000. All were noncorporate, noncelebrity users, and they were not tweeting for commercial purposes. Half the users were put into a control group, and the authors recorded daily data on the participants’ number of followers and their tweeting activity over a period of two months.

The researchers then had undergraduate research assistants create 100 Twitter accounts. Following Twitter’s terms of service, the assistants added realistic-looking names and locations for these accounts, and they had the accounts follow one another as well as popular users such as Lady Gaga and Justin Bieber. The assistants even sent out simple tweets—“It’s a pretty day today” or “The sky is blue” — to further support the illusion that the accounts were operated by real people.

Over the ensuing two months, the assistants used the new accounts to follow the users in the test group, gradually increasing each user’s list of followers by 100. The authors monitored these accounts to see how the increase in audience size affected the users’ tweeting activity.

Users who had few followers initially showed no change in their tweeting habits. Similarly, “high-end” users — those with as many as 10,000 followers — did not exhibit much change, likely because 100 additional followers was “a drop in the bucket,” Stephen said.

Among “mid-range” users, however, the authors noted significant changes in tweeting activity. “Users with 13-26 followers did increase activity,” said Stephen, speculating that these users were encouraged by the increase in followers to post more to a suddenly larger audience.

But users with slightly more followers — 62-245 — showed the opposite instinct, posting less as their followers increased. These users already had achieved some level of status, Stephen said, and wanted to preserve it by avoiding posting anything that would offend their followers. “As they get more followers,” he said, “they want to be careful about what they post.” These results indicated to the researchers that many users were more interested in gaining followers than in using Twitter to broadcast their views.

There is a natural tendency, Stephen explained, for active users to gain followers over time. Because users will post less as they gain followers, it’s natural to conclude, Stephen said, that Twitter users are going to post less.

But commercial users, celebrities and institutions like schools and sports teams will continue to post information to the people who want it. “So what it becomes is another advertising channel, a broadcast medium, as opposed to a socially interactive one,” Stephen said.

Such a change is prevented, for now, by the influx of new users to Twitter. If Twitter should reach a point where no new users are signing up, the shift away from an interactive platform toward a one-way conduit for information would become more likely.

In such a scenario, Twitter would remain a viable channel for corporations, celebrities and other high-end users to communicate with their fans, Stephen said. They might use their Twitter feeds the same way they use mailing lists to announce products and promotions to their followers.

“Longer term,” Stephen said, “to get value, they’ll need the people who start following them to react to these tweets and to retweet them.” But as this research suggests, over time, regular users will be less likely to do so. Marketers using Twitter will be challenged to offer incentives to engage users and counteract the tendency to tweet less.

The paper appears in the May/June issue of Marketing Science.

This research was supported by the Katz school, Columbia and INSEAD.