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Vol. LXIV, No. 7
March 30, 2012
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Digest

New Method Discovered to Label Cells for Tracking by MRI

Researchers have developed a method to label transplanted cells so they can be tracked by magnetic resonance imaging (MRI). In the future, as cell therapies become a more integral part of regenerative medicine and tumor treatment, there could be increased need to measure how many transplanted immune or stem cells reach their target.

A team combined three FDA-approved drugs to form a complex that, when incubated in transplant cells, labeled nearly 100 percent of those cells for MRI imaging in animal models. The team was led by Dr. Joseph Frank, chief of the Clinical Center Radiology and Imaging Sciences Laboratory of Diagnostic Radiology Research.

“Less than 3 percent of intravenous transplanted cells get to their target,” he said. “This brings up questions of cell dose, multiple doses and dose timing and how to make cell therapy approaches more effective.”

Cell death and distribution to other areas prevent most treatment cells from reaching the intended site. By using MRI to track cell arrival or homing to the desired site, researchers can compare dosage amounts and frequency for the most beneficial treatment.

The new technology, pending regulatory agency review, will be first tested in humans in an ongoing trial at the City of Hope Medical Center in Duarte, Calif. Supported by the California Institute of Regenerative Medicine, the study is testing the transplant of genetically engineered neural stem cells on patients with a type of brain tumor.

Researchers from Henry Ford Hospital, Detroit, and the National Institute of Biomedical Imaging and Bioengineering also contributed to the Nature Medicine article.

Study Defines Treatment Window for HIV-Positive Children Infected at Birth

HIV-positive children older than 1 year who were treated after showing moderate HIV-related symptoms did not experience greater cognitive or behavior problems compared to peers treated when signs of their infection were still mild, according to a study funded by NIH. But both groups of HIV-positive children lagged behind HIV-negative children in these areas, suggesting that the first year of life may present a critical treatment window for minimizing impairments in brain development due to HIV.

As part of the NIH-funded Pediatric Randomized Early vs. Deferred Initiation in Cambodia and Thailand (PREDICT) trial, researchers assessed 284 HIV-positive children ages 1-12 who had mildly weakened immune systems but no severe symptoms of HIV infection. The children were randomly assigned to receive treatment immediately or to have treatment deferred until they began to show moderate signs of HIV-related illness.

At follow-up almost 3 years later, very few children in either group had progressed to AIDS. Children who received deferred treatment performed as well as those treated immediately on tests measuring intelligence, memory and hand-eye coordination. However, both groups scored lower on these tests and had more behavior problems than HIV-negative children who took part in the PREDICT study.

“These findings suggest that the window of opportunity for avoiding neurocognitive deficits by treating HIV infection may only occur earlier, in infancy,” noted Dr. Pim Brouwers, who oversees NIMH-funded research on HIV/AIDS among children and adolescents and also served as a co-investigator on neurodevelopmental outcomes of the PREDICT study.

The results of the PREDICT study were presented at the 19th Conference on Retroviruses and Opportunistic Infections in Seattle. PREDICT was sponsored by the National Institute of Allergy and Infectious Diseases, with further neurological analysis of the study participants supported by NIMH and NICHD.

Nearly 800,000 Deaths Prevented Due to Declines in Smoking

Tobacco control efforts in the U.S. have included restrictions on smoking in public places, increases in cigarette excise taxes, limits on underage access to cigarettes and efforts to increase public awareness
Tobacco control efforts in the U.S. have included restrictions on smoking in public places, increases in cigarette excise taxes, limits on underage access to cigarettes and efforts to increase public awareness of the hazards of smoking.

Twentieth-century tobacco control programs and policies were responsible for preventing more than 795,000 lung cancer deaths in the United States from 1975 through 2000, according to an analysis funded by the National Cancer Institute.

If all cigarette smoking in this country had ceased following the release of the first Surgeon General’s report on smoking and health in 1964, a total of 2.5 million people would have been spared from death due to lung cancer in the 36 years following that report, according to the analysis. The results of the study were published online Mar. 14 in the Journal of the National Cancer Institute.

The researchers, part of the NCI-sponsored Cancer Intervention and Surveillance Modeling Network, used a comparative modeling approach in which they constructed detailed cigarette smoking histories for individuals born from 1890 through 1970, and then related the histories to lung cancer mortality in mathematical models. Using these models, the researchers were able to estimate the impact of changes in smoking patterns resulting from tobacco control activities on lung cancer deaths during the period from 1975 through 2000. Since the 1964 report, tobacco control efforts in the U.S. have included restrictions on smoking in public places, increases in cigarette excise taxes, limits on underage access to cigarettes and efforts to increase public awareness of the hazards of smoking.—compiled by Carla Garnett


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