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'Sleep debts' accrue when nightly sleep totals six hours or fewer

Those who believe they can function well on six or fewer hours of sleep every night may be accumulating a “sleep debt” that cuts into their normal cognitive abilities, according to research conducted at the University of Pennsylvania School of Medicine. What’s more, the research indicates, those people may be too sleep-deprived to know it. The study, published in the March 15 issue of the journal Sleep, found that chronically sleep-deprived individuals reported feeling “only slightly sleepy” even when their performance was at its worst during standard psychological testing. The results provide scientific insight into the daily challenges that confront military personnel, residents and on-call doctors and surgeons, shift workers, parents of young children, and others who routinely get fewer than six hours of sleep each night.

Insect antibiotic hijacks bacteria's DNA

For antibiotics, the best way to beat bacterial defenses may be to avoid them altogether. Researchers at University of Pennsylvania School of Medicine have discovered that Cecropin A, a member of a family of antibiotic proteins produced by insects, may kill bacteria and avoid resistance by entering bacterial cells and taking control of their genetic machinery.
While most antibiotics kill bacteria by attacking critical enzyme systems, Cecropin A somehow slips inside the bacteria and turns specific genes on and off. The findings challenge conventional thinking on how these antibiotics function, and may aid in turning antimicrobial peptides like Cecropin A into therapeutic agents.

Gene Explains Heart Abnormalities Associated with Neurofibromatosis

While type 1 Neurofibromatosis (NF1) is primarily known to cause tumors of the nervous system, scientists were puzzled as to why patients with NF1 are also prone to cardiovascular problems such as hypertension and congenital heart disease. Researchers from the University of Pennsylvania School of Medicine have solved this particular part of the puzzle by showing how the Nf1 gene – which is mutated in those suffering from Neurofibromatosis – is also essential in endothelial cells, the cells that make up blood vessels.

Leukemia-Related Protein is a Master Editor of the ‘Histone Code’

Rearrangements of the mixed lineage leukemia gene, MLL, are associated with aggressive leukemias in both children and adults. Researchers at the University of Pennsylvania School of Medicine have found that one portion of the MLL protein is an enzyme that “edits” the so-called histone code, a series of modifications to proteins associated with DNA that influence how and when certain genes are turned on and off. Their findings are presented in the November issue of Molecular Cell.