The two oxidation states of ceria nanoparticles, Ce3+ and Ce4+, play a pivotal role in scavenging reactive oxygen species (ROS). In particular, Ce3+ is largely responsible for removing O2− and .OH ...that are associated with inflammatory response and cell death. The synthesis is reported of 2 nm ceria–zirconia nanoparticles (CZ NPs) that possess a higher Ce3+/Ce4+ ratio and faster conversion from Ce4+ to Ce3+ than those exhibited by ceria nanoparticles. The obtained Ce0.7Zr0.3O2 (7CZ) NPs greatly improve ROS scavenging performance, thus regulating inflammatory cells in a very low dose. Moreover, 7CZ NPs are demonstrated to be effective in reducing mortality and systemic inflammation in two representative sepsis models. These findings suggest that 7CZ NPs have the potential as a therapeutic nanomedicine for treating ROS‐related inflammatory diseases.
An optimized ROS scavenging agent: 2 nm‐sized ceria–zirconia nanoparticles (CZ NPs) with increased Ce3+ ratios outperform ceria NPs as scavengers of reactive oxygen species (ROS). The composition‐tuned 7CZ (Ce0.7Zr0.3O2) NPs are superior in reducing inflammation in vitro and decrease the mortality in sepsis in vivo.
The translation of MRS to clinical practice has been impeded by the lack of technical standardization. There are multiple methods of acquisition, post‐processing, and analysis whose details greatly ...impact the interpretation of the results. These details are often not fully reported, making it difficult to assess MRS studies on a standardized basis. This hampers the reviewing of manuscripts, limits the reproducibility of study results, and complicates meta‐analysis of the literature. In this paper a consensus group of MRS experts provides minimum guidelines for the reporting of MRS methods and results, including the standardized description of MRS hardware, data acquisition, analysis, and quality assessment. This consensus statement describes each of these requirements in detail and includes a checklist to assist authors and journal reviewers and to provide a practical way for journal editors to ensure that MRS studies are reported in full.
This paper sets out the expert consensus on minimum reporting guidelines for MRS studies. It includes a checklist as a practical way for authors and journal editors to ensure that MRS studies are reported appropriately. A common set of reporting standards will greatly increase transparency, rigor, and replicability of MRS studies, and should further the successful integration of MRS into widespread clinical practice.
With a 40‐year history of use for in vivo studies, the terminology used to describe the methodology and results of magnetic resonance spectroscopy (MRS) has grown substantially and is not consistent ...in many aspects. Given the platform offered by this special issue on advanced MRS methodology, the authors decided to describe many of the implicated terms, to pinpoint differences in their meanings and to suggest specific uses or definitions. This work covers terms used to describe all aspects of MRS, starting from the description of the MR signal and its theoretical basis to acquisition methods, processing and to quantification procedures, as well as terms involved in describing results, for example, those used with regard to aspects of quality, reproducibility or indications of error. The descriptions of the meanings of such terms emerge from the descriptions of the basic concepts involved in MRS methods and examinations. This paper also includes specific suggestions for future use of terms where multiple conventions have emerged or coexisted in the past.
This work defines terms and explains concepts used to describe all aspects of MR spectroscopy, starting from the definition of the MR signal and its theoretical basis to acquisition methods, processing and quantification procedures, as well as terms involved in describing results, including quality aspects, reproducibility or indications of error. Also featured are specific suggestions for future use of terms where multiple conventions have emerged or previously coexisted.
This Preface introduces the Special Issue entitled, “Energy Substrates and Microbiome Govern Brain Bioenergetics and Cognitive Function with Aging”, which is comprised of manuscripts contributed by ...invited speakers and program/organizing committee members who participated in the 14th International Conference on Brain Energy Metabolism (ICBEM) held on October 24–27, 2022 in Santa Fe, New Mexico, USA. The conference covered the latest developments in research related to neuronal energetics, emerging roles for glycogen in higher brain functions, the impact of dietary intervention on aging, memory, and Alzheimer's disease, roles of the microbiome in gut‐brain signaling, astrocyte‐neuron interactions related to cognition and memory, novel roles for mitochondria and their metabolites, and metabolic neuroimaging in aging and neurodegeneration. The special issue contains 25 manuscripts on these topics plus three tributes to outstanding scientists who have made important contributions to brain energy metabolism and participated in numerous ICBEM conferences. In addition, two of the manuscripts describe important directions and the rationale for future research in many thematic areas covered by the conference.
This special issue, entitled “Energetics and cognition in aging brain: Impact of substrates and microbiome”, contains manuscripts from attendees at the 14th International Conference on Brain Energy Metabolism (ICBEM) held in Santa Fe, New Mexico, USA, October 24–27, 2022. Major topics include neuronal and mitochondrial energetics, higher brain functions involving astrocyte‐neuron interactions, unique roles for glycogen, glycolytic upregulation during activation, determination of metabolite levels with genetically‐encoded biosensors, dietary intervention in aging, gut‐brain signaling, spreading depolarization and functional brain imaging in aging, brain injury, and neurodegeneration. Two manuscripts provide roadmaps for future research.
Cover image for this issue: https://doi.org/10.1111/jnc.15857
This is a tribute to Sebastián Cerdán, a brilliant and innovative NMR spectroscopist whose studies contributed greatly to the fundamental information to the understanding of brain metabolism, ...particularly in regard to multinuclear magnetic resonance spectroscopy (MRS) techniques. Sebastián Cerdán sadly passed away in May 2022. He was a wonderful mentor and colleague who will be greatly missed.
Sebastián Cerdán, a wonderful colleague and brilliant and innovative NMR spectroscopist sadly passed away in May 2022. His studies using multinuclear magnetic resonance spectroscopy (MRS) techniques contributed greatly to the understanding of brain metabolism, including identification of the pyruvate recycling pathway in brain and determining metabolic changes in the brain related to appetite regulation and the development of obesity. He will be greatly missed. Photo of Sebastián Cerdán on the Great Wall of China at the 3rd International Society for Neurochemistry (ISN) Special. Conference/8th International Conference on Brain Energy Metabolism (ICBEM) meeting in Beijing, China in 2008.
The excitatory neurotransmitter glutamate has a role in neuronal migration and process elongation in the central nervous system (CNS). The effects of chronic glutamate hyperactivity on vesicular and ...protein transport within CNS neurons, that is, processes necessary for neurite growth, have not been examined previously. In this study, we measured the effects of lifelong hyperactivity of glutamate neurotransmission on axoplasmic transport in CNS neurons. We compared wild‐type (wt) to transgenic (Tg) mice over‐expressing the glutamate dehydrogenase gene Glud1 in CNS neurons and exhibiting increases in glutamate transmitter formation, release, and synaptic activation in brain throughout the lifespan. We found that Glud1 Tg as compared with wt mice exhibited increases in the rate of anterograde axoplasmic transport in neurons of the hippocampus measured in brain slices ex vivo, and in olfactory neurons measured in vivo. We also showed that the in vitro pharmacologic activation of glutamate synapses in wt mice led to moderate increases in axoplasmic transport, while exposure to selective inhibitors of ion channel forming glutamate receptors very significantly suppressed anterograde transport, suggesting a link between synaptic glutamate receptor activation and axoplasmic transport. Finally, axoplasmic transport in olfactory neurons of Tg mice in vivo was partially inhibited following 14‐day intake of ethanol, a known suppressor of axoplasmic transport and of glutamate neurotransmission. The same was true for transport in hippocampal neurons in slices from Glud1 Tg mice exposed to ethanol for 2 h ex vivo. In conclusion, endogenous activity at glutamate synapses regulates and glutamate synaptic hyperactivity increases intraneuronal transport rates in CNS neurons.
Lee et al. present an ex vivo and in vivo study of axonal transport in a transgenic mouse model of chronic glutamate neurotransmission hyperactivity, which over‐expresses the glutamate dehydrogenase gene (Glud1) in CNS neurons and exhibits increased glutamate transmitter formation, release, and synaptic activation. Glud1 versus wild‐type mice exhibited an increased rate of anterograde axoplasmic transport in hippocampal neurons in ex vivo and in olfactory neurons in vivo. Pharmacologic experiments in brain slices suggested a link between synaptic glutamate receptor activation and axoplasmic transport. Overall, the study demonstrates that endogenous Glu neurotransmission hyperactivity enhances anterograde axonal transport rates in the CNS neurons.
Long acquisition times due to intrinsically low signal‐to‐noise ratio and the need for highly homogeneous B0 field make MRS particularly susceptible to motion or scanner instability compared with ...MRI. Motion‐induced changes in both localization and shimming (ie B0 homogeneity) degrade MRS data quality. To mitigate the effects of motion three approaches can be employed: (1) subject immobilization, (2) retrospective correction, and (3) prospective real‐time correction using internal and/or external tracking methods. Prospective real‐time correction methods can simultaneously update localization and the B0 field to improve MRS data quality. While localization errors can be corrected with both internal (navigators) and external (optical camera, NMR probes) tracking methods, the B0 field correction requires internal navigator methods to measure the B0 field inside the imaged volume and the possibility to update the scanner shim hardware in real time. Internal and external tracking can rapidly update the MRS localization with submillimeter and subdegree precision, while scanner frequency and first‐order shims of scanner hardware can be updated by internal methods every sequence repetition. These approaches are most well developed for neuroimaging, for which rigid transformation is primarily applicable. Real‐time correction greatly improves the stability of MRS acquisition and quantification, as shown in clinical studies on subjects prone to motion, including children and patients with movement disorders, enabling robust measurement of metabolite signals including those with low concentrations, such as gamma‐aminobutyric acid and glutathione. Thus, motion correction is recommended for MRS users and calls for tighter integration and wider availability of such methods by MR scanner manufacturers.
MRS data quality is severely degraded by motion due to long scan times, low signal‐to‐noise ratio, the need for highly homogeneous B0 field to resolve spectral overlap, and the strong coupling between localization and B0 homogeneity. Effects of motion can be mitigated by retrospective correction, and prospective real‐time correction using internal and/or external tracking methods. The best MRS data quality can be obtained by prospective real‐time motion correction, which simultaneously updates localization and the B0 field.
Purpose
To develop a new rapid spatial filtering method for lipid removal, fast lipid reconstruction and removal processing (FLIP), which selectively isolates and removes interfering lipid signals ...from outside the brain in a full‐FOV 2D MRSI and whole‐brain 3D echo planar spectroscopic imaging (EPSI).
Theory and Methods
FLIP uses regularized least‐squares regression based on spatial prior information from MRI to selectively remove lipid signals originating from the scalp and measure the brain metabolite signals with minimum cross contamination. FLIP is a noniterative approach, thus allowing a rapid processing speed, and uses only spatial information without any spectral priors. The performance of FLIP was compared with the Papoulis‐Gerchberg algorithm (PGA), Hankel singular value decomposition (HSVD), and fast image reconstruction with L2 regularization (L2).
Results
FLIP in both 2D and 3D MRSI resulted in consistent metabolite quantification in a greater number of voxels with less concentration variation than other algorithms, demonstrating effective and robust lipid‐removal performance. The percentage of voxels that met quality criteria with FLIP, PGA, HSVD, and L2 processing were 90%, 57%, 29%, and 42% in 2D MRSI, and 80%, 75%, 76%, and 74% in 3D EPSI, respectively. The quantification results of full‐FOV MRSI using FLIP were comparable to those of volume‐localized MRSI, while allowing significantly increased spatial coverage. FLIP performed the fastest in 2D MRSI.
Conclusion
FLIP is a new lipid‐removal algorithm that promises fast and effective lipid removal with improved volume coverage in MRSI.
In October 2022, Erysiphe powdery mildew from the section Typhulochaeta was found on Quercus aliena for the first time in Korea. Based on morphological characteristics and molecular‐phylogenetic ...analysis of the internal transcribed spacer region (ITS) and large subunit (LSU) gene sequences of the rDNA, the fungus was identified as Erysiphe japonica var. japonica. This is the first report of E. japonica var. japonica in Korea and the third report of this mildew on Q. aliena, with this current fungus‐host association spreading to China and Japan. Based on Korean samples, this study provides detailed morphology and molecular phylogeny of E. japonica var. japonica.
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