Publications by authors named "Steward A"

Traumatic brain injury is widely viewed as a risk factor for dementia, but the biological mechanisms underlying this association are still unclear. In previous studies, traumatic brain injury has been associated with the hallmark pathologies of Alzheimer's disease, i.e.

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In Alzheimer's disease (AD), amyloid-β (Aβ) triggers the aggregation and spreading of tau pathology, which drives neurodegeneration and cognitive decline. However, the pathophysiological link between Aβ and tau remains unclear, which hinders therapeutic efforts to attenuate Aβ-related tau accumulation. Aβ has been found to trigger neuronal hyperactivity and hyperconnectivity, and preclinical research has shown that tau spreads across connected neurons in an activity-dependent manner.

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Introduction: The COVID-19 pandemic has had a significant and ongoing impact on health care, particularly for medical radiation science (MRS) professionals. There exist many studies that describe the negative effects of clinical placement restrictions and access to universities on the well-being of all health professional students during the pandemic. There also exists evidence of changes to MRS student teaching and impacts to students and academic clinical educators; however, there exists a paucity of research that investigates how changes have affected the performance of students within the clinical environment and entering the workforce.

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In Alzheimer's disease (AD), Aβ triggers p-tau secretion, which drives tau aggregation. Therefore, it is critical to characterize modulators of Aβ-related p-tau increases which may alter AD trajectories. Here, we assessed whether factors known to alter tau levels in AD modulate the association between fibrillar Aβ and secreted p-tau determined in the cerebrospinal fluid (CSF).

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More than half of the world's rivers dry up periodically, but our understanding of the biological communities in dry riverbeds remains limited. Specifically, the roles of dispersal, environmental filtering and biotic interactions in driving biodiversity in dry rivers are poorly understood. Here, we conduct a large-scale coordinated survey of patterns and drivers of biodiversity in dry riverbeds.

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Background: Preclinical, postmortem, and positron emission tomography (PET) imaging studies have pointed to neuroinflammation as a key pathophysiological hallmark in primary 4-repeat (4R) tauopathies and its role in accelerating disease progression.

Objective: We tested whether microglial activation (1) progresses in similar spatial patterns as the primary pathology tau spreads across interconnected brain regions, and (2) whether the degree of microglial activation parallels tau pathology spreading.

Methods: We examined in vivo associations between tau aggregation and microglial activation in 31 patients with clinically diagnosed 4R tauopathies, using 18F-PI-2620 PET and 18F-GE180 (translocator protein [TSPO]) PET.

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Article Synopsis
  • Four-repeat tauopathies are brain diseases that happen when a protein called 4R tau builds up in certain areas of the brain, affecting how it works.
  • Two main types of these diseases are progressive supranuclear palsy (PSP) and corticobasal degeneration, which both cause problems in brain regions that are important for movement and other functions.
  • The researchers are trying to figure out how the problems in one part of the brain (subcortical) affect other connected areas (cortical) by studying patients and using special brain scans to see how these changes relate to each other.
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As cancer therapies increase in effectiveness and patients' life expectancies improve, balancing oncologic efficacy while reducing acute and long-term cardiovascular toxicities has become of paramount importance. To address this pressing need, the Cardiology Oncology Innovation Network (COIN) was formed to bring together domain experts with the overarching goal of collaboratively investigating, applying, and educating widely on various forms of innovation to improve the quality of life and cardiovascular healthcare of patients undergoing and surviving cancer therapies. The COIN mission pillars of innovation, collaboration, and education have been implemented with cross-collaboration among academic institutions, private and public establishments, and industry and technology companies.

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Orofacial clefts of the lip and palate are widely recognized to result from complex gene-environment interactions, but inadequate understanding of environmental risk factors has stymied development of prevention strategies. We interrogated the role of DNA methylation, an environmentally malleable epigenetic mechanism, in orofacial development. Expression of the key DNA methyltransferase enzyme DNMT1 was detected throughout palate morphogenesis in the epithelium and underlying cranial neural crest cell (cNCC) mesenchyme, a highly proliferative multipotent stem cell population that forms orofacial connective tissue.

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Article Synopsis
  • - In Alzheimer's disease, amyloid-beta (Aβ) causes tau pathology to spread through the brain, and abnormal synaptic activity contributes to this process.
  • - The study examined 93 patients and found that higher levels of the presynaptic protein GAP-43, which indicates synaptic changes, were linked to quicker tau accumulation related to Aβ.
  • - The results suggest that targeting synapses could be a potential strategy for preventing the spread of tau pathology in Alzheimer's, highlighting the connection between synaptic changes and tau spread.
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The aim of this qualitative, phenomenological study was to understand how older adults cope with experiences of ageism and racism through an intersectional lens. Twenty adults 60+ residing in the U.S.

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Importance: For the Alzheimer disease (AD) therapies to effectively attenuate clinical progression, it may be critical to intervene before the onset of amyloid-associated tau spreading, which drives neurodegeneration and cognitive decline. Time points at which amyloid-associated tau spreading accelerates may depend on individual risk factors, such as apolipoprotein E ε4 (ApoE4) carriership, which is linked to faster disease progression; however, the association of ApoE4 with amyloid-related tau spreading is unclear.

Objective: To assess if ApoE4 carriers show accelerated amyloid-related tau spreading and propose amyloid positron emission tomography (PET) thresholds at which tau spreading accelerates in ApoE4 carriers vs noncarriers.

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Introduction: This study illustrates image rejection rates of the lateral wrist x-ray projection at a large, public teaching hospital. Rejected images were evaluated to determine the number of images that needed to be repeated based on the clinical indication. This study highlights the difference in subjective image-repeat decision-making skills existing between radiologists, experienced radiographers and junior radiographers.

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This cross-sectional study examined whether internalized age stereotypes mediate the relationship between volunteering and self-efficacy for adults 50+ years of age. A convenience sample of volunteers (n = 173) residing in the United States of America Mountain West completed a 15-min, online survey. The independent variable was number of volunteer hours per week (mean = 6.

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Objectives: Ageism is a prevalent, insidious social justice issue that has harmful effects on the health of older adults. Preliminary literature explores the intersectionality of ageism with sexism, ableism, and ageism experienced among LGBTQ+ older adults. Yet, the intersectionality of ageism with racism remains largely absent from the literature.

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Microglial activation occurs early in Alzheimer's disease (AD) and previous studies reported both detrimental and protective effects of microglia on AD progression. Here, we used CSF sTREM2 to investigate disease stage-dependent drivers of microglial activation and to determine downstream consequences on AD progression. We included 402 patients with measures of earliest beta-amyloid (CSF Aβ ) and late-stage fibrillary Aβ pathology (amyloid-PET centiloid), as well as sTREM2, p-tau , and FDG-PET.

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Background: Frem1 has been linked to human face shape variation, dysmorphology, and malformation, but little is known about its regulation and biological role in facial development.

Results: During midfacial morphogenesis in mice, we observed Frem1 expression in the embryonic growth centers that form the median upper lip, nose, and palate. Expansive spatial gradients of Frem1 expression in the cranial neural crest cell (cNCC) mesenchyme of these tissues suggested transcriptional regulation by a secreted morphogen.

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Introduction: Lower network segregation is associated with accelerated cognitive decline in Alzheimer's disease (AD), yet it is unclear whether less segregated brain networks facilitate connectivity-mediated tau spreading.

Methods: We combined resting state functional magnetic resonance imaging (fMRI) with longitudinal tau positron emission tomography (PET) in 42 betamyloid-negative controls and 81 amyloid beta positive individuals across the AD spectrum. Network segregation was determined using resting-state fMRI-assessed connectivity among 400 cortical regions belonging to seven networks.

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Background: Tau-PET is a prognostic marker for cognitive decline in Alzheimer's disease, and the heterogeneity of tau-PET patterns matches cognitive symptom heterogeneity. Thus, tau-PET may allow precision-medicine prediction of individual tau-related cognitive trajectories, which can be important for determining patient-specific cognitive endpoints in clinical trials. Here, we aimed to examine whether tau-PET in cognitive-domain-specific brain regions, identified via fMRI meta-analyses, allows the prediction of domain-specific cognitive decline.

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Intergenerational programs have long been employed to reduce ageism and optimize youth and older adult development. Most involve in-person meetings, which COVID-19 arrested. ​​Needs for safety and social contact were amplified during COVID-19, leading to modified programming that engaged generations remotely rather than eliminating it.

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Although memory is known to play a key role in creativity, previous studies have not isolated the critical component processes and networks. We asked participants to generate links between words that ranged from strongly related to completely unrelated in long-term memory, delineating the neurocognitive processes that underpin more unusual versus stereotypical patterns of retrieval. More creative responses to strongly associated word-pairs were associated with greater engagement of episodic memory: in highly familiar situations, semantic, and episodic stores converge on the same information enabling participants to form a personal link between items.

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In Alzheimer's disease (AD), younger symptom onset is associated with accelerated disease progression and tau spreading, yet the mechanisms underlying faster disease manifestation are unknown. To address this, we combined resting-state fMRI and longitudinal tau-PET in two independent samples of controls and biomarker-confirmed AD patients (ADNI/BioFINDER, n = 240/57). Consistent across both samples, we found that younger symptomatic AD patients showed stronger tau-PET in globally connected fronto-parietal hubs, i.

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