Health-Medical-Fitness-Diet-zk: Reveals

vineri, 9 decembrie 2011

Long-Term Imaging Reveals Intriguing Patterns Of Human Brain Maturation

Main Category: Neurology / Neuroscience
Article Date: 09 Dec 2011 - 0:00 PST

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Neuroimaging has provided fascinating insight into the dynamic nature of human brain maturation. However, most studies of developmental changes in brain anatomy have considered individual locations in relative isolation from all others and have not characterized relationships between structural changes in different parts of the developing brain. Now, new research describes the first comprehensive study of coordinated anatomical maturation within the developing human brain. The study, published by Cell Press in the December 8 issue of the journal Neuron, reveals that functionally connected brain regions mature together and uncovers fascinating sex-specific differences in brain development.

"Understanding patterns of structural change in the developing human brain is a challenge because the types of change that we can detect using neuroimaging unfold rather slowly," explains lead study author, Dr. Armin Raznahan, from the National Institutes of Mental Health in Bethesda, Maryland. "So, we drew from the largest and longest-running longitudinal neuroimaging study of human brain maturation, where brain changes were tracked for over several years in the same set of individuals, to analyze patterns of correlated anatomical change across the sensitive developmental window of late childhood, adolescence, and early adulthood."

Dr. Raznahan and colleagues examined the thickness of the cortex because it can be reliably measured and its developmental changes have been described in detail. The cortex is a sheet of neural tissue that covers the surface of the brain and plays a key role in thought, language, memory and consciousness.

The researchers discovered that rates of structural maturation were highly coordinated in the cortex and that regions which were functionally connected to each other also exhibited tightly coupled patterns of maturation. Interestingly, the researchers also observed that maturational coupling within the brain regions crucial for complex decision making differed between males and females.

"Our study represents the first ever investigation of correlated anatomical maturation in the developing human brain and shows that rates of structural cortical development in different cortical regions are highly organized with respect to one another," concludes Dr. Raznahan. "By providing the first link between cortical connectivity and the coordination of cortical development, we reveal a previously unseen property of healthy brain maturation, which may represent a target for neurodevelopmental disease processes and a substrate for sexually dimorphic behavior in adolescence."

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
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joi, 8 decembrie 2011

Supercomputer Reveals New Details Behind Drug-Processing Protein Model

Main Category: Pharma Industry / Biotech Industry
Also Included In: IT / Internet / E-mail
Article Date: 08 Dec 2011 - 1:00 PST

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Supercomputer simulations at the Department of Energy's Oak Ridge National Laboratory are giving scientists unprecedented access to a key class of proteins involved in drug detoxification.

Jerome Baudry and Yinglong Miao, who are jointly affiliated with ORNL and the University of Tennessee, have performed simulations to observe the motions of water molecules in a class of enzymes called P450s. Certain types of P450 are responsible for processing a large fraction of drugs taken by humans.

The supercomputer simulations were designed to help interpret ongoing neutron experiments.

"We simulated what happens in this enzyme over a time scale of 0.3 microseconds, which sounds very fast, but from a scientific point of view, it's a relatively long time," Baudry said. "A lot of things happen at this scale that had never been seen before. It's a computational tour de force to be able to follow that many water molecules for that long."

The team's study of the water molecules' movements contributes to a broader understanding of drug processing by P450 enzymes. Because some populations have a slightly different version of the enzymes, scientists hypothesize that mutations could partially explain why people respond differently to the same drug. One possibility is that the mutations might shut down the channels that bring water molecules in and out of the enzyme's active site, where the chemical modification of drugs takes place. This could be investigated by using the computational tools developed for this research.

By simulating how water molecules move in and out of the protein's centrally located active site, the team clarified an apparent contradiction between experimental evidence and theory that had previously puzzled researchers. X-ray crystallography, which provides a static snapshot of the protein, had shown only six water molecules present in the active site, whereas experimental observations indicated a higher number of water molecules would be present in the enzyme.

"We found that even though there can be many water molecules -- up to 12 at a given time that get in and out very quickly -- if you look at the average, those water molecules prefer to be at a certain location that corresponds to what you see in the crystal structure," Miao said. "It's a very dynamic hydration process that we are exploring with a combination of neutron scattering experiments and simulation."

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our pharma industry / biotech industry section for the latest news on this subject. The simulation research is published in Biophysical Journal as "Active-Site Hydration and Water Diffusion in Cytochrome P450cam: A Highly Dynamic Process."
The team was supported by an Experimental Program to Stimulate Competitive Research (EPSCOR) grant from the DOE Office of Science and funding from the University of Tennessee. Computing time on the Kraken supercomputer was supported by a National Science Foundation TeraGrid award.
ORNL is managed by UT-Battelle for the Department of Energy's Office of Science.
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