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1.
Prev Med ; 186: 108070, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39029743

RESUMO

OBJECTIVE: Accumulating more steps/day is associated with a lower risk of cancer mortality and composite cancer outcomes. However, less is known about the relationship of steps/day with the risk of multiple site-specific cancers. METHODS: This study included >22,000 women from the Women's Health Accelerometry Collaboration Cohort (2011-2022), comprised of women from the Women's Health Study and Women's Health Initiative Objective Physical Activity and Cardiovascular Health Study. Steps/day and step intensity were collected with accelerometry. Incident cancer cases and deaths were adjudicated. Stratified Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of the associations of steps/day and step intensity with incident breast, colon, endometrial, lung, and ovarian cancers, a composite of 13 physical activity-related cancers, total invasive cancer, and fatal cancer. RESULTS: On average, women were 73.4 years old, accumulated 4993 steps/day, and had 7.9 years of follow-up. There were small nonsignificant inverse associations with the risks of colon cancer (HR = 0.94, 95% CI: 0.83, 1.05), endometrial cancer (HR = 0.91, 95% CI: 0.82, 1.01), and fatal cancer (HR = 0.95 95% CI: 0.90, 1.00) per 1000 steps/day. More minutes at ≥40 steps/min and a faster peak 10- and 30-min step cadence were associated with a lower risk of endometrial cancer, but findings were attenuated after adjustment for body mass index and steps/day. CONCLUSIONS: Among women 62-97 years, there were small nonsignificant inverse associations of colon, endometrial, and fatal cancer with more steps/day. Epidemiologic studies with longer follow-up and updated assessments are needed to further explore these associations.

2.
Nano Lett ; 24(23): 6974-6980, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38829211

RESUMO

The plateau phase transition in quantum anomalous Hall (QAH) insulators corresponds to a quantum state wherein a single magnetic domain gives way to multiple domains and then reconverges back to a single magnetic domain. The layer structure of the sample provides an external knob for adjusting the Chern number C of the QAH insulators. Here, we employ molecular beam epitaxy to grow magnetic topological insulator multilayers and realize the magnetic field-driven plateau phase transition between two QAH states with odd Chern number change ΔC. We find that critical exponents extracted for the plateau phase transitions with ΔC = 1 and ΔC = 3 in QAH insulators are nearly identical. We construct a four-layer Chalker-Coddington network model to understand the consistent critical exponents for the plateau phase transitions with ΔC = 1 and ΔC = 3. This work will motivate further investigations into the critical behaviors of plateau phase transitions with different ΔC in QAH insulators.

3.
bioRxiv ; 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38915516

RESUMO

White matter hyperintensities (WMHs) are commonly detected on T2-weighted magnetic resonance imaging (MRI) scans, occurring in both typical aging and Alzheimer's disease. Despite their frequent appearance and their association with cognitive decline, the molecular factors contributing to WMHs remain unclear. In this study, we investigated the transcriptomic profiles of two commonly affected brain regions with coincident AD pathology-frontal subcortical white matter (frontal-WM) and occipital subcortical white matter (occipital-WM)-and compared with age-matched healthy controls. Through RNA-sequencing in frontal- and occipital-WM bulk tissues, we identified an upregulation of genes associated with brain vasculature function in AD white matter. To further elucidate vasculature-specific transcriptomic features, we performed RNA-seq analysis on blood vessels isolated from these white matter regions, which revealed an upregulation of genes related to protein folding pathways. Finally, comparing gene expression profiles between AD individuals with high- versus low-WMH burden showed an increased expression of pathways associated with immune function. Taken together, our study characterizes the diverse molecular profiles of white matter changes in AD compared to normal aging and provides new mechanistic insights processes underlying AD-related WMHs.

4.
Nano Lett ; 24(26): 7962-7971, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38885199

RESUMO

The interface of two materials can harbor unexpected emergent phenomena. One example is interface-induced superconductivity. In this work, we employ molecular beam epitaxy to grow a series of heterostructures formed by stacking together two nonsuperconducting antiferromagnetic materials, an intrinsic antiferromagnetic topological insulator MnBi2Te4 and an antiferromagnetic iron chalcogenide FeTe. Our electrical transport measurements reveal interface-induced superconductivity in these heterostructures. By performing scanning tunneling microscopy and spectroscopy measurements, we observe a proximity-induced superconducting gap on the top surface of the MnBi2Te4 layer, confirming the coexistence of superconductivity and antiferromagnetism in the MnBi2Te4 layer. Our findings will advance the fundamental inquiries into the topological superconducting phase in hybrid devices and provide a promising platform for the exploration of chiral Majorana physics in MnBi2Te4-based heterostructures.

5.
bioRxiv ; 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38915560

RESUMO

The brain's complex distributed dynamics are typically quantified using a limited set of manually selected statistical properties, leaving the possibility that alternative dynamical properties may outperform those reported for a given application. Here, we address this limitation by systematically comparing diverse, interpretable features of both intra-regional activity and inter-regional functional coupling from resting-state functional magnetic resonance imaging (rs-fMRI) data, demonstrating our method using case-control comparisons of four neuropsychiatric disorders. Our findings generally support the use of linear time-series analysis techniques for rs-fMRI case-control analyses, while also identifying new ways to quantify informative dynamical fMRI structures. While simple statistical representations of fMRI dynamics performed surprisingly well (e.g., properties within a single brain region), combining intra-regional properties with inter-regional coupling generally improved performance, underscoring the distributed, multifaceted changes to fMRI dynamics in neuropsychiatric disorders. The comprehensive, data-driven method introduced here enables systematic identification and interpretation of quantitative dynamical signatures of multivariate time-series data, with applicability beyond neuroimaging to diverse scientific problems involving complex time-varying systems.

6.
Artigo em Inglês | MEDLINE | ID: mdl-38791742

RESUMO

Colombia hosts the largest number of refugees and migrants fleeing the humanitarian emergency in Venezuela, many of whom experience high levels of displacement-related trauma and adversity. Yet, Colombian mental health services do not meet the needs of this population. Scalable, task-sharing interventions, such as Group Problem Management Plus (Group PM+), have the potential to bridge this gap by utilizing lay workers to provide the intervention. However, the current literature lacks a comprehensive understanding of how and for whom Group PM+ is most effective. This mixed methods study utilized data from a randomized effectiveness-implementation trial to examine the mediators and moderators of Group PM+ on mental health outcomes. One hundred twenty-eight migrant and refugee women in northern Colombia participated in Group PM+ delivered by trained community members. Patterns in moderation effects showed that participants in more stable, less marginalized positions improved the most. Results from linear regression models showed that Group PM+-related skill acquisition was not a significant mediator of the association between session attendance and mental health outcomes. Participants and facilitators reported additional possible mediators and community-level moderators that warrant future research. Further studies are needed to examine mediators and moderators contributing to the effectiveness of task-shared, scalable, psychological interventions in diverse contexts.


Assuntos
Saúde Mental , Refugiados , Migrantes , Humanos , Colômbia , Refugiados/psicologia , Feminino , Venezuela , Adulto , Migrantes/psicologia , Migrantes/estatística & dados numéricos , Pessoa de Meia-Idade , Adulto Jovem
7.
Glob Ment Health (Camb) ; 11: e32, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38572247

RESUMO

As evidence supporting the effectiveness of mental health and psychosocial interventions grows, more research is needed to understand optimal strategies for improving their implementation in diverse contexts. We conducted a qualitative process evaluation of a multicomponent psychosocial intervention intended to promote well-being among refugee, migrant and host community women in three diverse contexts in Ecuador and Panamá. The objective of this study is to describe the relationships among implementation determinants, strategies and outcomes of this community-based psychosocial intervention. The five implementation strategies used in this study included stakeholder engagement, promoting intervention adaptability, group and community-based delivery format, task sharing and providing incentives. We identified 10 adaptations to the intervention and its implementation, most of which were made during pre-implementation. Participants (n = 77) and facilitators (n = 30) who completed qualitative interviews reported that these strategies largely improved the implementation of the intervention across key outcomes and aligned with the study's intervention and implementation theory of change models. Participants and facilitators also proposed additional strategies for improving reach, implementation and maintenance of this community-based psychosocial intervention.

8.
Artigo em Inglês | MEDLINE | ID: mdl-38673310

RESUMO

Research on mental health and psychosocial support (MHPSS) interventions within refugee and migrant communities has increasingly focused on evaluating implementation, including identifying strategies to promote retention in services. This study examines the relationship between participant characteristics, study setting, and reasons for intervention noncompletion using data from the Entre Nosotras feasibility trial, a community-based MHPSS intervention targeting refugee, migrant, and host community women in Ecuador and Panama that aimed to promote psychosocial wellbeing. Among 225 enrolled women, approximately half completed the intervention, with varying completion rates and reasons for nonattendance across study sites. Participants who were older, had migrated for family reasons, had spent more time in the study community, and were living in Panamá (vs. Ecuador) were more likely to complete the intervention. The findings suggest the need to adapt MHPSS interventions to consider the duration of access to the target population and explore different delivery modalities including the role of technology and cellular devices as reliable or unreliable source for engaging with participants. Engaging younger, newly arrived women is crucial, as they showed lower completion rates. Strategies such as consulting scheduling preferences, providing on-site childcare, and integrating MHPSS interventions with other programs could enhance intervention attendance.


Assuntos
Saúde Mental , Refugiados , Humanos , Feminino , Refugiados/psicologia , Adulto , Pessoa de Meia-Idade , Equador , Migrantes/psicologia , Migrantes/estatística & dados numéricos , Adulto Jovem , Panamá , Sistemas de Apoio Psicossocial , Apoio Social , América Latina
9.
Artigo em Inglês | MEDLINE | ID: mdl-38397657

RESUMO

Refugees and migrants experience an elevated risk for mental health problems and face significant barriers to receiving services. Interpersonal counseling (IPC-3) is a three-session intervention that can be delivered by non-specialists to provide psychological support and facilitate referrals for individuals in need of specialized care. We piloted IPC-3 delivered remotely by eight Venezuelan refugee and migrant women living in Peru. These counselors provided IPC-3 to Venezuelan refugee and migrant clients in Peru (n = 32) who reported psychological distress. Clients completed assessments of mental health symptoms at baseline and one-month post-intervention. A subset of clients (n = 15) and providers (n = 8) completed post-implementation qualitative interviews. Results showed that IPC-3 filled a gap in the system of mental health care for refugees and migrants in Peru. Some adaptations were made to IPC-3 to promote its relevance to the population and context. Non-specialist providers developed the skills and confidence to provide IPC-3 competently. Clients displayed large reductions in symptoms of depression (d = 1.1), anxiety (d = 1.4), post-traumatic stress (d = 1.0), and functional impairment (d = 0.8). Remote delivery of IPC-3 by non-specialists appears to be a feasible, acceptable, and appropriate strategy to address gaps and improve efficiency within the mental health system and warrants testing in a fully powered effectiveness study.


Assuntos
COVID-19 , Refugiados , Migrantes , Humanos , Feminino , Refugiados/psicologia , Projetos Piloto , Peru/epidemiologia , Pandemias , COVID-19/epidemiologia , Aconselhamento
10.
J Cereb Blood Flow Metab ; : 271678X231216144, 2023 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-38000018

RESUMO

Cerebrovascular dysfunction is a significant contributor to Alzheimer's disease (AD) progression. AD mouse models show altered capillary morphology, density, and diminished blood flow in areas of tau and beta-amyloid accumulation. The purpose of this study was to examine alterations in vascular structure and their contributions to perfusion deficits in the hippocampus in AD and mild cognitive impairment (MCI). Seven individuals with AD and MCI (1 AD/6 MCI), nine cognitively intact older healthy adults, and seven younger healthy adults underwent pseudo-continuous arterial spin labeling (PCASL) and gradient-echo/spin-echo (GESE) dynamic susceptibility contrast (DSC) MRI. Cerebral blood flow (CBF), cerebral blood volume, relative vessel size index (rVSI), and mean vessel density were calculated from model fitting. Lower CBF from PCASL and SE DSC MRI was observed in the hippocampus of AD/MCI group. rVSI in the hippocampus of the AD/MCI group was larger than that of the two healthy groups (FDR-P = 0.02). No difference in vessel density was detected between the groups. We also explored relationship of tau burden from 18F-flortaucipir positron emission tomography and vascular measures from MRI. Tau burden was associated with larger vessel size and lower CBF in the hippocampus. We postulate that larger vessel size may be associated with vascular alterations in AD/MCI.

11.
Glob Ment Health (Camb) ; 10: e42, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37854436

RESUMO

Community-based psychosocial interventions are key elements of mental health and psychosocial support; yet evidence regarding their effectiveness and implementation in humanitarian settings is limited. This study aimed to assess the appropriateness, acceptability, feasibility and safety of conducting a cluster randomized trial evaluating two versions of a group psychosocial intervention. Nine community clusters in Ecuador and Panamá were randomized to receive the standard version of the Entre Nosotras intervention, a community-based group psychosocial intervention co-designed with community members, or an enhanced version of Entre Nosotras that integrated a stress management component. In a sample of 225 refugees, migrants and host community women, we found that both versions were safe, acceptable and appropriate. Training lay facilitators to deliver the intervention was feasible. Challenges included slow recruitment related to delays caused by the COVID-19 pandemic, high attrition due to population mobility and other competing priorities, and mixed psychometric performance of psychosocial outcome measures. Although the intervention appeared promising, a definitive cluster randomized comparative effectiveness trial requires further adaptations to the research protocol. Within this pilot study we identified strategies to overcome these challenges that may inform adaptations. This comparative effectiveness design may be a model for identifying effective components of psychosocial interventions.

12.
Front Microbiol ; 14: 1239167, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37675430

RESUMO

The avian gut microbiota has been the subject of considerable recent attention, with potential implications for diverse fields such as the poultry industry, microbial ecology, and conservation. Faecal microbiotas are frequently used as a non-invasive proxy for the gut microbiota, however the extraction of high-quality microbial DNA from avian faeces has often proven challenging. Here we aimed to evaluate the performance of two DNA preservation methods (95% ethanol and RNAlater) and five extraction approaches (IndiSpin Pathogen Kit, QIAamp PowerFecal Pro DNA Kit, MicroGEM PrepGEM Bacteria Kit, ZymoBIOMICS DNA Miniprep Kit, and an in-house phase separation-based method) for studying the avian gut microbiota. Systematic testing of the efficacy of these approaches on faecal samples from an initial three avian species (chicken, ostrich, and the flightless parrot kakapo) revealed substantial differences in the quality, quantity and integrity of extracted DNA, but negligible influence of applied method on 16S rRNA gene-based microbiota profiles. Subsequent testing with a selected combination of preservation and extraction method on 10 further phylogenetically and ecologically diverse avian species reiterated the efficacy of the chosen approach, with bacterial community structure clustering strongly by technical replicates for a given avian species. Our finding that marked differences in extraction efficacy do not appear to influence 16S rRNA gene-based bacterial community profiles provides an important foundation for ongoing research on the avian gut microbiota.

13.
Confl Health ; 17(1): 7, 2023 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-36804874

RESUMO

Populations affected by armed conflict and other humanitarian crises are at elevated risk for mental health problems. While the COVID-19 pandemic has had broadly deleterious effects on livelihoods, economic well-being, and population health worldwide, vulnerable groups have been disproportionately impacted by the pandemic. Providing mental health and psychosocial support (MHPSS) services during these times to vulnerable groups, especially in low- and middle-income countries and humanitarian settings, is essential. In an effort to comply with the public health response to the pandemic and mitigate COVID-19 transmission, significant implementation adaptations were made to service delivery during the pandemic. This short report describes several strategies to ensure that equity was central to these adaptations and public health responses, and provides recommendations for ensuring continuity of this progress post-pandemic. Examples and key lessons learned are given related to strategies to increase access to MHPSS services, improve meaningful stakeholder engagement, develop and support community networks, and implement community-based psychosocial support groups. They come from diverse settings of Bangladesh, Colombia, Ecuador, and Lebanon. The COVID-19 pandemic has highlighted the importance of preventing and treating MHPSS issues. It also has created opportunities for innovative programming to address overlooked problems, improve the quality of services provided, and increase focus on equity. It is vital that we use the momentum and attention generated around MHPSS services during the COVID-19 pandemic to continue to build and improve existing MHPSS services in more equitable ways for vulnerable populations.

14.
Transcult Psychiatry ; 60(3): 496-507, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36114647

RESUMO

There is considerable variation in the presentation of mental health problems across cultural contexts. Most screening and assessment tools do not capture local idioms and culturally specific presentations of distress, thus introducing measurement error and overlooking meaningful variation in mental health. Before applying screening and assessment tools in a particular context, a qualitative exploration of locally salient idioms and expression of distress can help assess whether existing measures are appropriate in a specific context as well as what adaptations may improve their construct validity. We aimed to employ a mixed-methods approach to describe and measure cultural concepts of distress among female Congolese survivors of intimate partner violence in Nyarugusu refugee camp, Tanzania. This sequential study used data from 55 qualitative (free-listing and in-depth) interviews followed by 311 quantitative interviews that included assessments of symptoms of common mental disorder to explore whether the symptom constellations were consistent across these methodologies. Results from thematic analysis of qualitative data and exploratory factor analysis of quantitative data converged on three concepts of distress: huzuni (deep sadness), msongo wa mawazo (stress, too many thoughts), and hofu (fear). The psychometric properties of these constructs were comparable to those of the three original common mental disorders measured by the quantitative symptom assessment tools-anxiety, depression, and post-traumatic stress disorder-adding weight to the appropriateness of using these tools in this specific setting. This mixed-methods approach presents an innovative additional method for assessing the local "cultural fit" of globally used tools for measuring mental health in cross-cultural research.


Assuntos
Refugiados , Transtornos de Estresse Pós-Traumáticos , Humanos , Feminino , Saúde Mental , Campos de Refugiados , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Transtornos de Ansiedade , Ansiedade , Refugiados/psicologia
15.
Nat Comput Sci ; 3(10): 883-893, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38177751

RESUMO

Scientists have developed hundreds of techniques to measure the interactions between pairs of processes in complex systems, but these computational methods-from contemporaneous correlation coefficients to causal inference methods-define and formulate interactions differently, using distinct quantitative theories that remain largely disconnected. Here we introduce a large assembled library of 237 statistics of pairwise interactions, and assess their behavior on 1,053 multivariate time series from a wide range of real-world and model-generated systems. Our analysis highlights commonalities between disparate mathematical formulations of interactions, providing a unified picture of a rich interdisciplinary literature. Using three real-world case studies, we then show that simultaneously leveraging diverse methods can uncover those most suitable for addressing a given problem, facilitating interpretable understanding of the quantitative formulation of pairwise dependencies that drive successful performance. Our results and accompanying software enable comprehensive analysis of time-series interactions by drawing on decades of diverse methodological contributions.

16.
Anim Microbiome ; 4(1): 55, 2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-36175950

RESUMO

BACKGROUND: The critically endangered kakapo is a flightless, nocturnal parrot endemic to Aotearoa New Zealand. Recent efforts to describe the gastrointestinal microbial community of this threatened herbivore revealed a low-diversity microbiota that is often dominated by Escherichia-Shigella bacteria. Given the importance of associated microbial communities to animal health, and increasing appreciation of their potential relevance to threatened species conservation, we sought to better understand the development of this unusual gut microbiota profile. To this end, we conducted a longitudinal analysis of faecal material collected from kakapo chicks during the 2019 breeding season, in addition to associated nest litter material. RESULTS: Using an experimental approach rarely seen in studies of threatened species microbiota, we evaluated the impact of a regular conservation practice on the developing kakapo microbiota, namely the removal of faecal material from nests. Artificially removing chick faeces from nests had negligible impact on bacterial community diversity for either chicks or nests (p > 0.05). However, the gut microbiota did change significantly over time as chick age increased (p < 0.01), with an increasing relative abundance of Escherichia-Shigella coli over the study period and similar observations for the associated nest litter microbiota (p < 0.01). Supplementary feeding substantially altered gut bacterial diversity of kakapo chicks (p < 0.01), characterised by a significant increase in Lactobacillus bacteria. CONCLUSIONS: Overall, chick age and hand rearing conditions had the most marked impact on faecal bacterial communities. Similarly, the surrounding nest litter microbiota changed significantly over time since a kakapo chick was first placed in the nest, though we found no evidence that removal of faecal material influenced the bacterial communities of either litter or faecal samples. Taken together, these observations will inform ongoing conservation and management of this most enigmatic of bird species.

17.
Anim Microbiome ; 4(1): 11, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35078539

RESUMO

BACKGROUND: The Aotearoa New Zealand takahe (Porphyrio hochstetteri), once thought to be extinct, is a nationally threatened flightless rail under intensive conservation management. While there has been previous research into disease-related microbes in takahe, little is known about the microbes present in the gastrointestinal tract. Given the importance of gut-associated microbes to herbivore nutrition and immunity, knowledge of these communities is likely to be of considerable conservation value. Here we examined the gut microbiotas of 57 takahe at eight separate locations across Aotearoa New Zealand. RESULTS: Faecal samples, taken as a proxy for the hindgut bacterial community, were subjected to 16S rRNA gene amplicon sequencing using Illumina MiSeq. Phylogenetic analysis of > 2200 amplicon sequence variants (ASVs) revealed nine main bacterial phyla (Acidobacteriota, Actinobacteriota, Bacteroidota, Campilobacterota, Firmicutes, Fusobacteriota, Planctomycetota, Proteobacteria, and Verrucomicrobiota) that accounted for the majority of sequence reads. Location was a significant effect (p value < 0.001, 9999 permutations) that accounted for 32% of the observed microbiota variation. One ASV, classified as Lactobacillus aviarius, was present in all samples at an average relative abundance of 17% (SD = 23.20). There was strong evidence (p = 0.002) for a difference in the abundance of the genus Lactobacillus between locations. A common commensal bacterium previously described in takahe, Campylobacter spp., was also detected in most faecal samples. CONCLUSIONS: Location plays a pivotal role in the observed variation among takahe gut bacterial communities and is potentially due to factors such as supplemental feeding and medical treatment experienced by birds housed in captivity at one of the eight sampled sites. These data present a first glimpse of the previously unexplored takahe gut microbiota and provide a baseline for future microbiological studies and conservation efforts.

18.
Curr Alzheimer Res ; 18(9): 711-720, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34825871

RESUMO

BACKGROUND: Reduced cerebrovascular function and accumulation of tau pathology are key components of cognitive decline in Alzheimer's disease (AD). Recent multimodal neuroimaging studies show a correlation between cortical tau accumulation and reduced cerebral perfusion. However, animal models predict that tau exerts capillary-level changes that may not be fully captured by standard imaging protocols. OBJECTIVE: Using newly-developed magnetic resonance imaging (MRI) technology to measure capillary- specific perfusion parameters, we examined a series of mild cognitive impairment (MCI) and AD patients with tau positron emission tomography (PET) to observe whole-brain capillary perfusion alterations and their association with tau deposition. METHODS: Seven subjects with MCI or AD received Flortaucipir PET to measure tau deposition and spin-echo dynamic susceptibility contrast (SE-DSC) MRI to measure microvascular perfusion (<10µm radius vessels). Gradient-echo (GE) DSC and pseudocontinuous arterial spin labeling (PCASL) MRI were also acquired to assess macrovascular perfusion. Tau PET, microvascular perfusion, and cortical thickness maps were visually inspected in volumetric slices and on cortical surface projections. RESULTS: High tau PET signal was generally observed in the lateral temporal and parietal cortices, with uptake in the occipital cortex in one subject. Global blood flow measured by PCASL was reduced with increasing tau burden, which was consistent with previous studies. Tau accumulation was spatially associated with variable patterns of microvascular cerebral blood flow (CBF) and oxygen extraction fraction (OEF) in the cortex and with increased capillary transit heterogeneity (CTH) in adjacent periventricular white matter, independent of amyloid-ß status. CONCLUSION: Although macrovascular perfusion generally correlated with tau deposition at the whole-cortex level, regional changes in microvascular perfusion were not uniformly associated with either tau pathology or cortical atrophy. This work highlights the heterogeneity of AD-related brain changes and the challenges of implementing therapeutic interventions to improve cerebrovascular function.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides , Humanos , Imageamento por Ressonância Magnética/métodos , Tomografia por Emissão de Pósitrons/métodos , Proteínas tau
19.
Front Neurol ; 11: 575953, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33041998

RESUMO

Alzheimer's Disease (AD) is associated with neuropathological changes, including aggregation of tau neurofibrillary tangles (NFTs) and amyloid-beta plaques. Mounting evidence indicates that vascular dysfunction also plays a key role in the pathogenesis and progression of AD, in part through endothelial dysfunction. Based on findings in animal models that tau pathology induces vascular abnormalities and cellular senescence, we hypothesized that tau pathology in the human AD brain leads to vascular senescence. To explore this hypothesis, we isolated intact microvessels from the dorsolateral prefrontal cortex (PFC, BA9) from 16 subjects with advanced Braak stages (Braak V/VI, B3) and 12 control subjects (Braak 0/I/II, B1), and quantified expression of 42 genes associated with senescence, cell adhesion, and various endothelial cell functions. Genes associated with endothelial senescence and leukocyte adhesion, including SERPINE1 (PAI-1), CXCL8 (IL8), CXCL1, CXCL2, ICAM-2, and TIE1, were significantly upregulated in B3 microvessels after adjusting for sex and cerebrovascular pathology. In particular, the senescence-associated secretory phenotype genes SERPINE1 and CXCL8 were upregulated by more than 2-fold in B3 microvessels after adjusting for sex, cerebrovascular pathology, and age at death. Protein quantification data from longitudinal plasma samples for a subset of 13 (n = 9 B3, n = 4 B1) subjects showed no significant differences in plasma senescence or adhesion-associated protein levels, suggesting that these changes were not associated with systemic vascular alterations. Future investigations of senescence biomarkers in both the peripheral and cortical vasculature could further elucidate links between tau pathology and vascular changes in human AD.

20.
Artigo em Inglês | MEDLINE | ID: mdl-32850496

RESUMO

Human microbiome studies remain focused on bacteria, as they comprise the dominant component of the microbiota. Recent advances in sequencing technology and optimization of amplicon sequencing protocols have allowed the description of other members of the microbiome, including eukaryotes (fungi) and, most recently, archaea. There are no known human-associated archaeal pathogens. Their diversity and contribution to health and chronic respiratory diseases, such as chronic rhinosinusitis (CRS), are unknown. Patients with CRS suffer from long-term sinus infections, and while the microbiota is hypothesized to play a role in its pathogenesis, the exact mechanism is poorly understood. In this cross-sectional study, we applied a recently optimized protocol to describe the prevalence, diversity and abundance of archaea in swab samples from the middle meatus of 60 individuals with and without CRS. A nested PCR approach was used to amplify the archaeal 16S rRNA gene for sequencing, and bacterial and archaeal load (also based on 16S rRNA genes) were estimated using Droplet Digital™ PCR (ddPCR). A total of 16 archaeal amplicon sequence variants (ASVs) from the phyla Euryarchaeota and Thaumarchaeota were identified. Archaeal ASVs were detected in 7/60 individuals, independent of disease state, whereas bacterial ASVs were detected in 60/60. Bacteria were also significantly more abundant than archaea. The ddPCR method was more sensitive than amplicon sequencing at detecting archaeal DNA in samples. Phylogenetic trees were constructed to visualize the evolutionary relationships between archaeal ASVs, isolates and clones. ASVs were placed into phylogenetic clades containing an apparent paucity of human-associated reference sequences, revealing how little studied the human archaeome is. This is the largest study to date to examine the human respiratory-associated archaeome, and provides the first insights into the prevalence, diversity and abundance of archaea in the human sinuses.


Assuntos
Microbiota , Sinusite , Archaea/genética , Estudos Transversais , Humanos , Filogenia , RNA Ribossômico 16S/genética
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