Hippocampal Glutathione Depletion and pH Increment in Alzheimer’s Disease: An in vivo MRS Study

Background: Oxidative stress plays a major role in Alzheimer’s disease (AD) pathogenesis, and thus, antioxidant glutathione (GSH) has been actively investigated in mitigating the oxidative load. Significant hippocampal GSH depletion has been correlated with cognitive impairment in AD. Furthermore, postmortem studies indicated alterations in cellular-energy metabolism and hippocampal pH change toward alkalinity in AD. Objective: Concurrent analysis of hippocampal GSH and pH interplay in vivo on the same individual is quite unclear and hence requires investigation to understand the pathological events in AD. Methods: Total 39 healthy old (HO), 22 mild cognitive impairment (MCI), and 37 AD patients were recruited for hippocampal GSH using 1H-MRS MEGA-PRESS and pH using 2D 31P-MRSI with dual tuned (1H/31P) transmit/receive volume head coil on 3T-Philips scanner. All MRS data processing using KALPANA package and statistical analysis were performed MedCalc, respectively and NINS-STAT package. Results: Significant GSH depletion in the left and right hippocampus (LH and RH) among MCI and AD study groups as compared to HO was observed, whereas pH increased significantly in the LH region between HO and AD. Hippocampal GSH level negatively correlated with pH in both patient groups. The ROC analysis on the combined effect of GSH and pH in both hippocampal regions give accuracy for MCI (LH: 78.27%; RH: 86.96%) and AD (LH: 88%; RH: 78.26%) groups differentiating from HO. Conclusion: Outcomes from this study provide further insights to metabolic alterations in terms of concurrent assessment of hippocampal GSH and pH levels in AD pathogenesis, aiding in early diagnosis of MCI and AD.

Reconsidering the Link Between Self-Reported Personality Traits and Political Preferences

Research on personality and political preferences generally assumes unidirectional causal influence of the former on the latter. However, there are reasons to believe that citizens might adopt what they perceive as politically congruent psychological attributes, or at least be motivated to view themselves as having these attributes. We test this hypothesis in a series of studies. Results of preregistered panel analyses in three countries suggest reciprocal causal influences between self-reported personality traits and political preferences. In two two-wave survey experiments, a subtle political prime at the beginning of a survey resulted in self-reported personality traits that were more aligned with political preferences gauged in a previous assessment. We discuss how concurrent assessment within the context of a political survey might overestimate the causal influence of personality traits on political preferences and how political polarization might be exacerbated by political opponents adopting different personality characteristics or self-perceptions thereof.

Rethinking the Link Between Self-Reported Personality Traits and Political Preferences

Research on personality and political preferences generally assumes unidirectional causal influence of the former on the latter. However, there are reasons to believe that citizens might adopt what they perceive as politically congruent psychological attributes, or at least be motivated to view themselves as having these attributes. We test this hypothesis in a series of studies. Results of preregistered panel analyses in three countries suggest reciprocal causal influences between self-reported personality traits and political preferences. In two two-wave survey experiments, a subtle political prime at the beginning of a survey resulted in self-reported personality traits that were more aligned with political preferences gauged in a previous assessment. We discuss how concurrent assessment within the context of a political survey might overestimate the causal influence of personality traits on political preferences, and how political polarization might be exacerbated by political opponents adopting different personality characteristics or self-perceptions thereof.

A data set linking large-scale, individual semantic networks and cognitive performance

We report data from a proof-of-concept study involving the concurrent assessment of large-scale individual semantic networks and cognitive performance. The data include 10,800 free associations--collected using a dedicated web-based platform over the course of 2-4 weeks--and responses to several cognitive tasks, including verbal fluency, episodic memory, associative recall tasks, from four younger and four older native German speakers. The data are unique in scope and composition and shed light on individual and age-related differences in mental representations and their role in cognitive performance across the lifespan.

Concurrent Assessment of Deformability and Adhesiveness of Sickle Red Blood Cells by Measuring Perfusion of an Adhesive Artificial Microvascular Network

Biomarker development is a key clinical research need in sickle cell disease (SCD). Hemorheological parameters are excellent candidates as abnormal red blood cell (RBC) rheology plays a critical role in SCD pathophysiology. Here we describe a microfluidic device capable of evaluating RBC deformability and adhesiveness concurrently, by measuring their effect on perfusion of an artificial microvascular network (AMVN) that combines microchannels small enough to require RBC deformation, and laminin (LN) coating on channel walls to model intravascular adhesion. Each AMVN device consists of three identical capillary networks, which can be coated with LN (adhesive) or left uncoated (non-adhesive) independently. The perfusion rate for sickle RBCs in the LN-coated networks (0.18 ± 0.02 nL/s) was significantly slower than in non-adhesive networks (0.20 ± 0.02 nL/s), and both were significantly slower than the perfusion rate for normal RBCs in the LN-coated networks (0.22 ± 0.01 nL/s). Importantly, there was no overlap between the ranges of perfusion rates obtained for sickle and normal RBC samples in the LN-coated networks. Interestingly, treatment with poloxamer 188 decreased the perfusion rate for sickle RBCs in LN-coated networks in a dose-dependent manner, contrary to previous studies with conventional assays, but in agreement with the latest clinical trial which showed no clinical benefit. Overall, these findings suggest the potential utility of the adhesive AMVN device for evaluating the effect of novel curative and palliative therapies on the hemorheological status of SCD patients during clinical trials and in post-market clinical practice.