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Archive - Dec 13, 2011

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Insulin Signaling Is Distorted in Pancreases of Type 2 Diabetics

Insulin signaling is altered in the pancreas in type 2 diabetes, a new study shows for the first time in humans. The errant signals disrupt both the number and quality of beta cells — the cells that produce insulin. The finding was published online on November 30, 2011 in the journal PLoS ONE. Dr. Franco Folli, of the School of Medicine at The University of Texas Health Science Center San Antonio, and Dr. Rohit Kulkarni, of the Joslin Diabetes Center, Harvard Medical School, Boston, are principal investigators of the study. In a statement, they said, "People knew there was a lack of beta cells because they die off in type 2 diabetes. Here we show the beta cells attempt to replicate, but this is unsuccessful because of the altered signals." Inability of the beta cells to replicate themselves results in a major defect in insulin secretion during the late stages of type 2 diabetes, said Drs. Folli and Kulkarni. Insulin is the hormone that lowers blood sugar after a meal. The study, which examined pancreases from cadaveric organ donors, suggests a potential strategy to prevent beta cells from being depleted — by restoring insulin signals back to normal. This could have important implications for millions of people with type 2 diabetes, a disease marked by poor regulation of blood sugar levels. Cells in most organs, except the central nervous system, turn over in cell division. One cell dies and another replicates to perform the same function. This is true in the islets of Langerhans, the area of the pancreas where beta cells and other blood glucose regulators originate. The new study also demonstrated, for the first time in humans, that the insulin receptor is critically important for maintaining beta cell mass. This had previously been seen in rodent knock-out models of type 2 diabetes mellitus.

MIT Scientists Link Patterns of Spider Silk and Musical Melodies

Using a new mathematical methodology, researchers at MIT have created a scientifically rigorous analogy that shows the similarities between the physical structure of spider silk and the sonic structure of a melody, proving that the structure of each relates to its function in an equivalent way. The step-by-step comparison begins with the primary building blocks of each item — an amino acid and a sound wave — and moves up to the level of a beta sheet nanocomposite (the secondary structure of a protein consisting of repeated hierarchical patterns) and a musical riff (a repeated pattern of notes or chords). The study explains that structural patterns are directly related to the functional properties of lightweight strength in the spider silk and, in the riff, sonic tension that creates an emotional response in the listener. While likening spider silk to musical composition may appear to be more novelty than breakthrough, the methodology behind it represents a new approach to comparing research findings from disparate scientific fields. Such analogies could help engineers develop materials that make use of the repeating patterns of simple building blocks found in many biological materials that, like spider silk, are lightweight yet extremely failure-resistant. The work also suggests that engineers may be able to gain new insights into biological systems through the study of the structure-function relationships found in music and other art forms. The MIT researchers — Dr. David Spivak, a postdoc in the Department of Mathematics, Associate Professor Dr. Markus Buehler of the Department of Civil and Environmental Engineering (CEE), and CEE graduate student Tristan Giesa — published their findings in the December issue of BioNanoScience.