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Vol. LXIV, No. 12
June 8, 2012

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Study Shows How Immune Cells Change Wiring of the Developing Mouse Brain

Researchers have shown in mice how immune cells in the brain target and remove unused connections between brain cells during normal development. This research, supported by NINDS, NIDA and NICHD, sheds light on how brain activity influences brain development and highlights the newly found importance of the immune system in how the brain is wired, as well as how the brain forms new connections throughout life in response to change.

Disease-fighting cells in the brain, known as microglia, can prune the billions of tiny connections (or synapses) between neurons, the brain cells that transmit information through electric and chemical signals. This new research demonstrates that microglia respond to neuronal activity to select synapses to prune and shows how this pruning relies on an immune response pathway—the complement system—to eliminate synapses in the way that bacterial cells or other pathogenic debris are eliminated. The study, reported in the May 24 issue of Neuro, was led by Dr. Beth Stevens of Children’s Hospital Boston and Harvard Medical School.

Poor-Quality Malaria Drugs Pose Threat

Poor-quality antimalarial drugs lead to drug resistance and inadequate treatment that pose an urgent threat to vulnerable populations, according to an NIH study published May 22 in The Lancet Infectious Diseases journal. Emergence of malaria strains that are resistant to artemisinin drugs on the Thailand-Cambodia border make it imperative to improve the drug supply, stressed the authors.

“Poor-quality antimalarial drugs are very likely to jeopardize the unprecedented progress and investments in control and elimination of malaria made in the past decade,” said Dr. Joel Breman, a coauthor on the paper and senior scientist emeritus at the Fogarty International Center, which funded the study.

By studying survey data of the malaria drugs available across Southeast Asia and sub-Saharan Africa, researchers found that from 20 to 42 percent are either poor quality or fake. Poor-quality samples were classified as falsified, substandard or degraded. Falsified drugs were fraudulently manufactured with fake packaging and usually no active ingredient or the wrong one. Substandard products were poorly manufactured with inadequate or too much active ingredient. Degraded supplies are good quality drugs that were compromised by poor storage.

Genetic Test Results Do Not Trigger Increased Use of Health Services

Receiving results of genetic testing does not appreciably drive up or diminish recipients’ demand for potentially costly follow-up health services, a study finds.
Receiving results of genetic testing does not appreciably drive up or diminish recipients’ demand for potentially costly follow-up health services, a study finds.

People have increasing opportunities to participate in genetic testing that can indicate their range of risk for developing a disease. Receiving these results does not appreciably drive up or diminish test recipients’ demand for potentially costly follow-up health services, according to a study by researchers at NIH and other institutions.

The study in the May 17 early online issue of Genetics in Medicine was done by investigators with the Multiplex Initiative, a multi-center collaborative initiative involving NIH’s Intramural Research Program, Group Health Cooperative in Seattle and the Henry Ford Health System in Detroit.

The tests are available from a growing number of commercial producers; health care providers have been uncertain whether people who received information only about risk would follow up by demanding diagnostic testing to monitor for predicted illnesses.

“We need to understand the impact of genomic discoveries on the health care system if these powerful technologies are going to improve human health,” said Dr. Dan Kastner of NHGRI. “We are still learning how to integrate new genomic discoveries into clinical care effectively and efficiently.”

Concentrated Saline Therapy Not Effective in Young Children with
Cystic Fibrosis

Inhaling concentrated saline (salt water) mist does not reduce how often infants and young children with cystic fibrosis (CF) need antibiotics for respiratory symptoms, according to findings from a clinical trial sponsored by NHLBI. This trial is the largest study of concentrated, or hypertonic, saline therapy in infants and preschoolers.

Previous findings have shown that hypertonic saline provides some benefits to adults and older children with CF. The saline mist appears to loosen the thick mucus that builds up in the lungs and may reduce the recurrent infections, known as pulmonary exacerbations, which are thought to contribute to the lung damage and respiratory failure associated with CF. Based on these 2006 findings, the use of hypertonic saline in younger children has been rising. About 1 in 5 children under 6 years old with CF currently use this therapy, but without any clear evidence that it is effective in these children.

“Even reasonably simple and non-toxic therapies can be burdensome, especially for families of small children with a chronic disease such as cystic fibrosis,” said pediatrician Dr. Susan Shurin, NHLBI acting director. “This is one more study that illustrates the importance of conducting clinical research in children because medicine is not one size fits all—therapies that benefit adults or even teenagers do not always benefit younger children in the same way.”

Results of the Infant Study of Inhaled Saline clinical trial were published online May 20 in the Journal of the American Medical Association.—compiled by Carla Garnett

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