Browsing by Subject "brain"

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    MRS fitting challenge data setup by ISMRM MRS study group
    (2021-04-16) Marjanska, Malgorzata; Deelchand, Dinesh K; Kreis, Roland; gosia@umn.edu; Marjanska, Malgorzata
    Fitting of the magnetic resonance spectroscopy (MRS) data plays an important role in the quantification of metabolite concentrations. A number of commercial and home-built packages are available and used by the MRS community to fit spectra. The question arose whether any one of these packages was superior to the others or whether they all perform similarly if appropriately used. Hence, in preparation for a workshop of the ISMRM MRS study group on MR Spectroscopy: from Current Best Practice to Latest Frontiers, which took place in August 2016, it was decided by the organizing committee, that this question should be tackled by a fitting challenge open to everybody, where a set of spectra would be evaluated. For this purpose, synthetic MRS data were generated for 28 datasets. Short-echo time PRESS spectra were simulated using ideal pulses for the common metabolites at mostly near-normal brain concentrations. A macromolecular contribution was also included. Modulations of signal-to-noise ratio (SNR), lineshape type and width, concentrations of γ-aminobutyric acid, glutathione and macromolecules, and inclusion of artifacts and lipid signals to mimic tumor spectra were included as challenges to be coped with.
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    Seasonal Metabolism Of Brown Adipose Tissue And Brain Mitochondria In The Thirteen-Lined Ground Squirrel (Ictidomys tridecemlineatus)
    (2015-08) Ballinger, Mallory
    During the hibernation season, thirteen-lined ground squirrels (Ictidomys tridecemlineatus) regularly cycle between bouts of torpor and interbout arousal (IBA). This presents a unique seasonal change in energy requirements in both the brain and brown adipose tissue (BAT). We hypothesized that brain and BAT mitochondria undergo a seasonal change in function to accommodate the variable energy demands of hibernation. To test this hypothesis, we examined mitochondrial bioenergetics of brain and BAT in thirteen-lined ground squirrels across five time points: summer, fall, torpor, IBA and spring. Through various molecular and functional analyses, we found significant increases in mitochondrial oxidative capacities of both brain and BAT during torpor and IBA. Overall, brain and BAT mitochondrial bioenergetics are not static across the year, and our studies suggest that these two tissues function efficiently during the hibernation season, when extreme physiological changes are occurring. These studies provide improved understanding of the overall energy requirements of a hibernator.