365 research outputs found

    The Impact of Cognitive Deficits and Spasticity on Driving Simulator Performance in Multiple Sclerosis

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    Multiple sclerosis (MS) is a demyelinating disease that can result in numerous sequelae. Although spasticity and cognitive dysfunction are common in MS, few studies have examined the impact of both factors on driving abilities in persons with physical impairments. The present study assessed driving performance in control participants and MS patients with documented spasticity using two brief simulations designed to measure lane tracking (under high cognitive load) and car following behavior. Seventeen MS patients and 9 controls participated in the study. The MS cohort exhibited a broad range of cognitive functioning (normal to significant impairment) and disability (Expanded Disability Status Scale scores of 3.0 to 7.5). Eight of the MS patients had significant spasticity in their right knee based upon the Modified Ashworth Spasticity Scale. MS patients had greater difficulty than controls on the simulations, particularly on the car following task. MS participants also tended to drive at higher speeds than the control participants. Within the MS cohort, cognitive dysfunction was most strongly associated with lane tracking decrements, whereas the possible relationship between cognitive function and car following behavior was eclipsed by lower limb spasticity. Spastic individuals had greater difficulty mirroring speed changes in the lead car, and were approximately one second slower in responding to its accelerations and decelerations. The current simulations provide important data regarding the impact various MS sequelae may have on driving performance, and may ultimately lead to clinical recommendations regarding specific driving behaviors and their associated risks

    You’ll change more than I will:Adults’ predictions about their own and others’ future preferences

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    It has been argued that adults underestimate the extent to which their preferences will change over time. We sought to determine whether such mis-predictions are the result of a difficulty imagining that one’s own current and future preferences may differ or whether it also characterizes our predictions about the future preferences of others. We used a perspective- taking task in which we asked young people how much they liked stereotypically-young-person items (e.g., Top 40 music, adventure vacations) and stereotypically-old-person items (e.g., jazz, playing bridge) now, and how much they would like them in the distant future (i.e., when they are 70 years old). Participants also made these same predictions for a generic same-age, same-sex peer. In a third condition, participants predicted how much a generic older (i.e., age 70) same-sex adult would like items from both categories today. Participants predicted less change between their own current and future preferences than between the current and future preferences of a peer. However, participants estimated that, compared to a current older adult today, their peer would like stereotypically-young items more in the future and stereotypically-old items less. The fact that peers’ distant-future estimated preferences were different from the ones they made for “current” older adults suggests that even though underestimation of change of preferences over time is attenuated when thinking about others, a bias still exists

    Island properties dominate species traits in determining plant colonizations in an archipelago system

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    The extrinsic determinants hypothesis emphasizes the essential role of environmental heterogeneity in species' colonization. Consequently, high resident species diversity can increase community susceptibility to colonizations because good habitats may support more species that are functionally similar to colonizers. On the other hand, colonization success is also likely to depend on species traits. We tested the relative importance of environmental characteristics and species traits in determining colonization success using census data of 587 vascular plant species collected about 70 yr apart from 471 islands in the archipelago of SW Finland. More specifically, we explored potential new colonization as a function of island properties (e.g. location, area, habitat diversity, number of resident species per unit area), species traits (e.g. plant height, life-form, dispersal vector, Ellenberg indicator values, association with human impact), and species' historical distributions (number of inhabited islands, nearest occurrence). Island properties and species' historical distributions were more effective than plant traits in explaining colonization outcomes. Contrary to the extrinsic determinants hypothesis, colonization success was neither associated with resident species diversity nor habitat diversity per se, although colonization was lowest on sparsely vegetated islands. Our findings lead us to propose that while plant traits related to dispersal and establishment may enhance colonization, predictions of plant colonizations primarily require understanding of habitat properties and species' historical distributions.Peer reviewe

    Biometal Dyshomeostasis in Olfactory Mucosa of Alzheimer's Disease Patients

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    Olfactory function, orchestrated by the cells of the olfactory mucosa at the rooftop of the nasal cavity, is disturbed early in the pathogenesis of Alzheimer's disease (AD). Biometals including zinc and calcium are known to be important for sense of smell and to be altered in the brains of AD patients. Little is known about elemental homeostasis in the AD patient olfactory mucosa. Here we aimed to assess whether the disease-related alterations to biometal homeostasis observed in the brain are also reflected in the olfactory mucosa. We applied RNA sequencing to discover gene expression changes related to metals in olfactory mucosal cells of cognitively healthy controls, individuals with mild cognitive impairment and AD patients, and performed analysis of the elemental content to determine metal levels. Results demonstrate that the levels of zinc, calcium and sodium are increased in the AD olfactory mucosa concomitantly with alterations to 17 genes related to metal-ion binding or metal-related function of the protein product. A significant elevation in alpha-2-macroglobulin, a known metal-binding biomarker correlated with brain disease burden, was observed on the gene and protein levels in the olfactory mucosa cells of AD patients. These data demonstrate that the olfactory mucosa cells derived from AD patients recapitulate certain impairments of biometal homeostasis observed in the brains of patients.Peer reviewe

    Neuron-astrocyte transmitophagy is altered in Alzheimer's disease

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    Under physiological conditions in vivo astrocytes internalize and degrade neuronal mitochondria in a process called transmitophagy. Mitophagy is widely reported to be impaired in neurodegeneration but it is unknown whether and how transmitophagy is altered in Alzheimer's disease (AD). Here we report that the internalization of neuronal mitochondria is significantly increased in astrocytes isolated from AD mouse brains. We also demonstrate that the degradation of neuronal mitochondria by astrocytes is increased in AD mice at the age of 6 months onwards. Furthermore, we demonstrate for the first time a similar phenomenon between human neurons and AD astrocytes, and in murine hippocampi in vivo. The results suggest the involvement of S100a4 in impaired mitochondrial transfer between neurons and AD astrocytes together with significant increases in the mitophagy regulator and reactive oxygen species in aged AD astrocytes. These findings demonstrate altered neuronsupporting functions of AD astrocytes and provide a starting point for studying the molecular mechanisms of transmitophagy in AD.Peer reviewe

    Single-Cell RNA-Seq Analysis of Olfactory Mucosal Cells of Alzheimer's Disease Patients

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    Olfaction is orchestrated by olfactory mucosal cells located in the upper nasal cavity. Olfactory dysfunction manifests early in several neurodegenerative disorders including Alzheimer's disease, however, disease-related alterations to the olfactory mucosal cells remain poorly described. The aim of this study was to evaluate the olfactory mucosa differences between cognitively healthy individuals and Alzheimer's disease patients. We report increased amyloid-beta secretion in Alzheimer's disease olfactory mucosal cells and detail cell-type-specific gene expression patterns, unveiling 240 differentially expressed disease-associated genes compared to the cognitively healthy controls, and five distinct cell populations. Overall, alterations of RNA and protein metabolism, inflammatory processes, and signal transduction were observed in multiple cell populations, suggesting their role in Alzheimer's disease-related olfactory mucosa pathophysiology. Furthermore, the single-cell RNA-sequencing proposed alterations in gene expression of mitochondrially located genes in AD OM cells, which were verified by functional assays, demonstrating altered mitochondrial respiration and a reduction of ATP production. Our results reveal disease-related changes of olfactory mucosal cells in Alzheimer's disease and demonstrate the utility of single-cell RNA sequencing data for investigating molecular and cellular mechanisms associated with the disease.Peer reviewe

    Acceptance of near-natural greenspace management relates to ecological and socio-cultural assigned values among European urbanites

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    Grasslands are widespread elements of urban greenspace providing recreational, psychological and aesthetic benefits to city residents. Two urban grassland types of contrasting management dominate urban greenspaces: frequently mown, species-poor short-cut lawns and less intensively managed, near-natural tall-grass meadows. The higher conservation value of tall-grass meadows makes management interventions such as converting short-cut lawns into tall-grass meadows a promising tool for urban biodiversity conservation. The societal success of such interventions, however, depends on identifying the values urban residents assign to different types of urban grasslands, and how these values translate to attitudes towards greenspace management. Using 2027 questionnaires across 19 European cities, we identify the assigned values that correlate with people's personal greenspace use and their preferences for different types of urban grasslands to determine how these values relate to the agreement with a scenario of converting 50 of their citiesĂąïżœïżœ short-cut lawns into tall-grass meadows. We found that most people assigned nature-related values, such as wildness, to tall-grass meadows and utility-related values, such as recreation, to short-cut lawns. Positive value associations of wildness and species richness with tall-grass meadows, and social and nature-related greenspace activities, positively correlated with agreeing to convert short-cut lawns into tall-grass meadows. Conversely, disapproval of lawn conversion correlated with positive value associations of cleanliness and recreation potential with short-cut lawns. Here, people using greenspaces for nature-related activities were outstandingly positive about lawn conversion. The results show that the plurality of values assigned to different types of urban grasslands should be considered in urban greenspace planning. For example, tall-grass meadows could be managed to also accommodate the values associated with short-cut lawns, such as tidiness and recreation potential, to support their societal acceptance

    Optimal In Silico Target Gene Deletion through Nonlinear Programming for Genetic Engineering

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    Optimal selection of multiple regulatory genes, known as targets, for deletion to enhance or suppress the activities of downstream genes or metabolites is an important problem in genetic engineering. Such problems become more feasible to address in silico due to the availability of more realistic dynamical system models of gene regulatory and metabolic networks. The goal of the computational problem is to search for a subset of genes to knock out so that the activity of a downstream gene or a metabolite is optimized.Based on discrete dynamical system modeling of gene regulatory networks, an integer programming problem is formulated for the optimal in silico target gene deletion problem. In the first result, the integer programming problem is proved to be NP-hard and equivalent to a nonlinear programming problem. In the second result, a heuristic algorithm, called GKONP, is designed to approximate the optimal solution, involving an approach to prune insignificant terms in the objective function, and the parallel differential evolution algorithm. In the third result, the effectiveness of the GKONP algorithm is demonstrated by applying it to a discrete dynamical system model of the yeast pheromone pathways. The empirical accuracy and time efficiency are assessed in comparison to an optimal, but exhaustive search strategy.Although the in silico target gene deletion problem has enormous potential applications in genetic engineering, one must overcome the computational challenge due to its NP-hardness. The presented solution, which has been demonstrated to approximate the optimal solution in a practical amount of time, is among the few that address the computational challenge. In the experiment on the yeast pheromone pathways, the identified best subset of genes for deletion showed advantage over genes that were selected empirically. Once validated in vivo, the optimal target genes are expected to achieve higher genetic engineering effectiveness than a trial-and-error procedure

    Examining the efficacy of a self-administered report form in missing person investigations

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    PurposeThe success of missing person investigations often centres on the quality of information obtained in the early stages. Reliable information can not only inform the search but might also become vital evidence if the case broadens into a criminal investigation relating to a sexual offence, abduction, or even murder. In addition to eliciting high quality information, police officers must consider that those close to the missing person are likely going through a very difficult and stressful time. Across two studies, we developed and tested a self-administered form (SAI-MISSING) designed to obtain reliable information that would meaningfully inform a missing person investigation, as well as providing a means for family and friends to be actively involved.MethodsIn Experiment 1, 65 participants were tested individually and asked to provide a description of a person they knew well but had not seen for 24 hours. In the second study, 64 participants were tested in pairs, but immediately separated into different rooms and instructed to imagine that the person they came with has gone missing. In both studies participants completed either the SAI-MISSING tool, or a self-administered control form.ResultsIn Experiment 1 we found that the SAI-MISSING tool elicited significantly more information regarding physical descriptions and descriptions of clothing and personal effects, than the comparison control form. In Experiment 2 we replicated this finding, and further showed that the SAI-MISSING tool produced higher accuracy rates than the control form.ConclusionsGiven our positive findings, potential applications of the tool are discussed
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