Study Finds Phenobarbital Fails to Prevent Brain Bleeding in Premature Infants
Phenobarbital -- once thought to be a promising treatment for preventing bleeding in the brains of premature infants when given to pregnant women at risk of premature delivery -- appears to be ineffective, according to the largest, most comprehensive clinical trial of its kind to date. The study, which appeared in the Aug. 14 New England Journal of Medicine, was conducted by researchers in the Neonatal Research Network, which is funded by NICHD. Support for the study was also provided by NCRR.
Bleeding in the brain, a dangerous complication of premature birth, affects 10,000 infants each year. Typically, the bleeding occurs deep in the brain, near the ventricles -- the hollow cavities inside the brain. Such bleeding may result in cerebral palsy, mental retardation or learning disabilities.
A few early clinical trials and a recent meta-analysis suggested that phenobarbital would be effective in reducing the frequency and severity of brain hemorrhaging in newborns. Because half of all such hemorrhaging occurs shortly before or at the time of birth, researchers had hoped that giving phenobarbital to pregnant women just before they delivered prematurely might reduce brain hemorrhaging in their babies after birth.
Genome Project Passes Important Milestone
The Human Genome Project passed an important milestone recently with the completion of a map of human chromosome 7, scientists announced in the journal Genome Research.
A team led by Dr. Eric Green of NHGRI has spent nearly 8 years developing a physical map of the chromosome, which contains an estimated 5 percent of the human genetic blueprint. The team used bits of human DNA isolated in yeast cells to localize more than 2,000 "landmarks" on chromosome 7. The landmarks are spaced at intervals of about 79,000 base pairs, the fundamental units of DNA.
The goal for the Human Genome Project is to map such a landmark every 100,000 base pairs. Chromosome 7 is the second human chromosome to have exceeded this goal, with the X chromosome being finished a few months ago. Chromosome 7 contains a total of 170 million base pairs.
With a physical map of human chromosome 7 in hand, the NHGRI team is now working closely with scientists at Washington University School of Medicine and the University of Washington to start sequencing the chromosome from beginning to end, base pair by base pair. By sequencing the entire human genome and its roughly 3 billion base pairs, scientists hope to identify all of the approximately 100,000 genes by early next century.
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