Direct in vivo assessment of sex-related metabolic differences in a mouse model of Alzheimer's disease by MRI

Solid state NMR/Biophysical Organic Chemistr

In vivo localized two dimensional MR spectroscopy to compare the neurochemical profile in wild-type and transgenic mouse of Alzheimer’s disease

Solid state NMR/Biophysical Organic Chemistr

In vivo longitudinal monitoring of blood flow alterations in TG2576 mouse model of Alzheimer's Disease

Solid state NMR/Biophysical Organic Chemistr

Quantifying effects of radiotherapy-induced microvascular injury; review of established and emerging brain MRI techniques

Microvascular changes are increasingly recognised not only as primary drivers of radiotherapy treatment response in brain tumours, but also as an important contributor to short- and long-term (cognitive) side effects arising from irradiation of otherwise healthy brain tissue. As overall survival of patients with brain tumours is increasing, monitoring long-term sequels of radiotherapy-induced microvascular changes in the context of their potential predictive power for outcome, such as cognitive disability, has become increasingly relevant. Ideally, radiotherapy-induced significant microvascular changes in otherwise healthy brain tissue should be identified as early as possible to facilitate adaptive radiotherapy and to proactively start treatment to minimise the influence on these side-effects on the final outcome. Although MRI is already known to be able to detect significant long-term radiotherapy induced microvascular effects, more recently advanced MR imaging biomarkers reflecting microvascular integrity and function have been reported and might provide a more accurate and earlier detection of microvascular changes. However, the use and validation of both established and new techniques in the context of monitoring early and late radiotherapy-induced microvascular changes in both target-tissue and healthy tissue currently are minimal at best. This review aims to summarise the performance and limitations of existing methods and future opportunities for detection and quantification of radiotherapy-induced microvascular changes, as well as the relation of these findings with key clinical parameters. (C) 2019 Elsevier B.V. All rights reserved

MRI assessment of blood flow artifacts in a transgenic mouse model of Alzheimer’s disease

Solid state NMR/Biophysical Organic Chemistr

Recent sedimentation of organic matter along the SE Atlantic Margin : A key for understanding deep offshore petroleum source rocks.

Classical views for the deposition of organic-rich sediments in deep-sea environments invoke two principal types of oceanographic and sedimentologic settings. The first is confined basins in which stratified oxygen depleted waters lead to anoxic preservation of organic matter in the water column and in underlying sediments (Demaison and Moore, 1980). The second is an open ocean setting where the episodic mass transfers due to slope sediment instability lead to the rapid burial of outer-shelf and upper slope-derived organic matter and its consequent preservation due to limited oxic or anoxic degradation (Stow, 1987). Other studies have shown, however, that organic matter in modern deep-sea sediments may occur in high amounts where oxygen is not significantly depleted (Pedersen and Calvert, 1990). Recent studies have demonstrated that highly biological productive areas, such as the upwelling zones associated to the Benguela Current in S-E Atlantic, may deliver sufficient quantity of organic material to (1) outbalance the degradative capacity of the water column and (2) sustain the formation of organic-rich sediments even in deep and oxygenated conditions (Bertrand et al., 2003). It appears that the S-E Atlantic margins provide a good example for revisiting the sedimentology of organic matter in deep water environments in the frame of the GDR Marges Continentales. This may have important implications for a better understanding of the distribution of ancient source rocks in deep offshore petroleum systems (Huc et al., 2001; Bertrand et al., 2003)

Associations between arterial stiffness, depressive symptoms and cerebral small vessel disease: cross-sectional findings from the AGES-Reykjavik Study.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Arterial stiffness may contribute to depression via cerebral microvascular damage, but evidence for this is scarce. We therefore investigated whether arterial stiffness is associated with depressive symptoms and whether cerebral small vessel disease contributes to this association.This cross-sectional study included a subset of participants from the AGES-Reykjavik study second examination round, which was conducted from 2007 to 2011. Arterial stiffness (carotid-femoral pulse wave velocity [CFPWV]), depressive symptoms (15-item geriatric depression scale [GDS-15]) and cerebral small vessel disease (MRI) were determined. Manifestations of cerebral small vessel disease included higher white matter hyperintensity volume, subcortical infarcts, cerebral microbleeds, Virchow-Robin spaces and lower total brain parenchyma volume.We included 2058 participants (mean age 79.6 yr; 59.0% women) in our analyses. Higher CFPWV was associated with a higher GDS-15 score, after adjustment for potential confounders (β 0.096, 95% confidence interval [CI] 0.005-0.187). Additional adjustment for white matter hyperintensity volume or subcortical infarcts attenuated the association between CFPWV and the GDS-15 score, which became nonsignificant (p > 0.05). Formal mediation tests showed that the attenuating effects of white matter hyperintensity volume and subcortical infarcts were statistically significant. Virchow-Robin spaces, cerebral microbleeds and cerebral atrophy did not explain the association between CFPWV and depressive symptoms.Our study was limited by its cross-sectional design, which precludes any conclusions about causal mediation. Depressive symptoms were assessed by a self-report questionnaire.Greater arterial stiffness is associated with more depressive symptoms; this association is partly accounted for by white matter hyperintensity volume and subcortical infarcts. This study supports the hypothesis that arterial stiffness leads to depression in part via cerebral small vessel disease.National Institutes of Health (NIH) N01-AG-12100 Intramural Research Program of the National Institute on Aging, USA Icelandic Heart Association Icelandic Parliament, Iceland National Institutes of Health, National Heart, Lung and Blood Institute HL094898 National Institute of Diabetes and Digestive and Kidney Diseases DK08244

Energetic ion depletions near Europa and Io: the effect of plumes and atmospheric charge exchange

Stars and planetary system

Multi-tracer model for staging cortical amyloid deposition using PET imaging

OBJECTIVE: To develop and evaluate a model for staging cortical amyloid deposition using PET with high generalizability. METHODS: 3027 subjects (1763 Cognitively Unimpaired (CU), 658 Impaired, 467 Alzheimer's disease (AD) dementia, 111 non-AD dementia, and 28 with missing diagnosis) from six cohorts (EMIF-AD, ALFA, ABIDE, ADC, OASIS-3, ADNI) who underwent amyloid PET were retrospectively included; 1049 subjects had follow-up scans. Applying dataset-specific cut-offs to global Standard Uptake Value ratio (SUVr) values from 27 regions, single-tracer and pooled multi-tracer regional rankings were constructed from the frequency of abnormality across 400 CU subjects (100 per tracer). The pooled multi-tracer ranking was used to create a staging model consisting of four clusters of regions as it displayed a high and consistent correlation with each single-tracer ranking. Relationships between amyloid stage, clinical variables and longitudinal cognitive decline were investigated. RESULTS: SUVr abnormality was most frequently observed in cingulate, followed by orbitofrontal, precuneal, and insular cortices, then the associative, temporal and occipital regions. Abnormal amyloid levels based on binary global SUVr classification were observed in 1.0%, 5.5%, 17.9%, 90.0%, and 100.0% of stage 0-4 subjects, respectively. Baseline stage predicted decline in MMSE (ADNI: N=867, F=67.37, p3000 subjects across cohorts and radiotracers, and detects pre-global amyloid burden and distinct risk profiles of cognitive decline within globally amyloid-positive subjects

Different phenotypes of neuropsychiatric systemic lupus erythematosus are related to a distinct pattern of structural changes on brain MRI

Objectives The underlying structural brain correlates of neuropsychiatric involvement in systemic lupus erythematosus (NPSLE) remain unclear, thus hindering correct diagnosis. We compared brain tissue volumes between a clinically well-defined cohort of patients with NPSLE and SLE patients with neuropsychiatric syndromes not attributed to SLE (non-NPSLE). Within the NPSLE patients, we also examined differences between patients with two distinct disease phenotypes: ischemic and inflammatory. Methods In this prospective (May 2007 to April 2015) cohort study, we included 38 NPSLE patients (26 inflammatory and 12 ischemic) and 117 non-NPSLE patients. All patients underwent a 3-T brain MRI scan that was used to automatically determine white matter, grey matter, white matter hyperintensities (WMH) and total brain volumes. Group differences in brain tissue volumes were studied with linear regression analyses corrected for age, gender, and total intracranial volume and expressed as B values and 95% confidence intervals. Results NPSLE patients showed higher WMH volume compared to non-NPSLE patients (p = 0.004). NPSLE inflammatory patients showed lower total brain (p = 0.014) and white matter volumes (p = 0.020), and higher WMH volume (p = 0.002) compared to non-NPSLE patients. Additionally, NPSLE inflammatory patients showed lower white matter (p = 0.020) and total brain volumes (p = 0.038) compared to NPSLE ischemic patients. Conclusion We showed that different phenotypes of NPSLE were related to distinct patterns of underlying structural brain MRI changes. Especially the inflammatory phenotype of NPSLE was associated with the most pronounced brain volume changes, which might facilitate the diagnostic process in SLE patients with neuropsychiatric symptoms.Neuro Imaging Researc