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September 22, 2017
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Robotic Exoskeleton Offers Approach to Alleviate Crouch Gait in Kids with Cerebral Palsy

Robotic Exoskeleton Offers Approach to Alleviate Crouch Gait in Kids with Cerebral Palsy

Researchers from the Clinical Center’s rehabilitation medicine department have created the first robotic exoskeleton specifically designed to treat crouch (or flexed-knee) gait in children with cerebral palsy by providing powered knee extension assistance at key points during the walking cycle.

Crouch gait, the excessive bending of the knees while walking, is a common and debilitating condition in children with cerebral palsy. Despite conventional treatments (including muscle injections, surgery, physical therapy and orthotics), crouch gait can lead to a progressive degeneration of the walking function, ultimately resulting in the loss of walking ability in roughly half of adults with the disorder.

CC researchers tested their prototype powered knee exoskeleton in a cohort study that followed 7 individuals between the ages of 5 and 19 who were diagnosed with crouch gait from cerebral palsy. The work was reported in Science Translational Medicine.

Walking with the exoskeleton was well-tolerated, with all participants able to walk independently without mobility aids or therapist assistance; six were able to do so in the first practice session. Improvements in knee extension were observed in six participants, with gains similar to or greater than average improvements reported from invasive surgical interventions. Importantly, the gains in knee extension occurred without a reduction in knee extensor muscle activity, indicating that these participants worked with the exoskeleton rather than offloading the task of straightening the leg during walking to the robot.

“Most wearable exoskeletons have been designed for adults with paralysis, with the exoskeleton replacing the user’s lost function,” said Dr. Thomas Bulea, principal investigator of the study. “We sought to create a device that could safely and effectively improve the posture of children with crouch gait while they walked. The improvements in their walking, along with their preserved muscle activity, make us optimistic that our approach could train a new walking pattern in these children if deployed over an extended time. This study paves the way for the exoskeleton’s use outside the clinic setting, greatly increasing the amount and intensity of gait training, which we believe is key to successful long-term outcomes in this population.”

Cerebral palsy is the most prevalent childhood movement disorder in the U.S., with approximately 10,000 new cases diagnosed each year. It is caused by a brain injury or abnormality in infancy or early childhood that disrupts the control of movement, posture and balance.

Zika Virus Selectively Infects, Kills Glioblastoma Cells in Mice

The Zika virus (ZIKV) may infect and kill a specific type of brain cancer cells while leaving normal adult brain tissue minimally affected, according to a new study supported by NIAID. In the paper, published online Sept. 5 in the Journal of Experimental Medicine, researchers describe the impact of ZIKV on glioblastoma cells in both human tissue samples and mice.

Even with current treatments, patients with glioblastomas—a highly malignant type of brain tumor—tend to have poor survival rates. Glioblastomas grow aggressively from a mass of unspecialized cells; ZIKV is known to infect similar cells in the nervous systems of developing fetuses. A fetus that acquires the virus from its ZIKV-infected mother during pregnancy can develop microcephaly and other serious abnormalities.

In this study, researchers at the University of California San Diego School of Medicine, Cleveland Clinic, Washington University School of Medicine in St. Louis and the University of Texas Medical Branch in Galveston introduced ZIKV to glioblastoma tissue samples removed from cancer patients as part of their treatment, as well as to healthy human neural tissue cultures. After 7 days, the researchers found that ZIKV had replicated in certain glioblastoma cells and prevented them from multiplying, while the ordinary neural tissue cultures remained largely uninfected.

The researchers also tested mice with glioblastomas, treating an experimental group with a mouse-adapted strain of ZIKV. Mice who received ZIKV survived longer than mice in the control group and their tumors were significantly smaller than those in the control mice after 1 week.

The researchers caution that ZIKV may behave differently when introduced to an active glioblastoma in a living person. Even if further studies continue to yield promising results, any potential treatment derived from ZIKV would need many years of rigorous testing for safety and efficacy.

Additional support for this study was provided in part by NCI and NINDS.

Sequencing All 24 Human Chromosomes Uncovers Rare Disorders

Extending noninvasive prenatal screening to all 24 human chromosomes can detect genetic disorders that may explain miscarriage and abnormalities during pregnancy, according to a study by researchers at NIH and other institutions. Because of the way data have been analyzed, typical genomic tests performed during pregnancy have targeted extra copies of chromosomes 21, 18 and 13, but rarely evaluated all 24 chromosomes. The study findings, which appeared in the Aug. 30 issue of Science Translational Medicine, may ultimately improve the accuracy of these tests, including by explaining why some give false-positive results.

Women often request noninvasive screening tests to detect genetic conditions. These tests, however, typically focus only on Down syndrome and other common trisomies. A trisomy is a condition in which there are three instances of a certain chromosome instead of the standard two.

“Extending our analysis to all chromosomes allowed us to identify risk for serious complications and potentially reduce false-positive results for Down syndrome and other genetic conditions,” said Dr. Diana Bianchi, senior author of the study and chief of NHGRI’s prenatal genomics and therapy section. She is also NICHD director.

Drug Combination Reduces Risk of HIV Infection Among Teen Males

An NIH network study has confirmed that a combination of two drugs taken daily to reduce the chances of HIV infection among high-risk adults also works well and appears safe in males ages 15 to 17 years.

Picture of pills

Truvada, a single pill containing the drugs tenofovir and emtricitabine, is currently approved for daily use in adults. The drug is the cornerstone of pre-exposure prophylaxis (PrEP), a strategy in which healthy people at risk for HIV infection take one or more anti-HIV drugs to reduce this risk.

The study, published in JAMA Pediatrics, was funded by NICHD, NIDA and NIMH.

“Several studies have shown that daily oral PrEP is effective in preventing HIV among people at high risk of becoming infected, but none of them included adolescents under age 18,” said study author Dr. Bill Kapogiannis of NICHD’s Maternal and Pediatric Infectious Diseases Branch. “Our study suggests that this therapy can safely reduce HIV risk for those under 18.”

NIH also is funding studies of PrEP therapy for girls and young women. In an upcoming NIH-funded study in several African countries, adolescent females ages 16-21 will use a vaginal ring for 6 months, oral PrEP for 6 months, then choose which method they want to use for the final 6 months of the study.

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