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Alzheimer's disease is marked by brain damage from tau and amyloid aggregates, particularly to the hippocampus and the default network. A new study in PLOS Biology shows sex differences in the patterns of damage and in their association with risk and protective factors.
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Doença de Alzheimer , Lesões Encefálicas , Feminino , Humanos , Masculino , Doença de Alzheimer/etiologia , Proteínas tau/metabolismo , Caracteres Sexuais , Alelos , Encéfalo/metabolismo , Apolipoproteínas E , Fatores de RiscoRESUMO
BACKGROUND: Too little is known about the effectiveness of efforts to prevent firearm violence. We evaluated California's Armed and Prohibited Persons System (APPS), which identifies legal purchasers of firearms who have become prohibited persons and seeks to recover all firearms and ammunition to which they have access. DESIGN AND METHODS: This cluster-randomised pragmatic trial was made possible by APPS's expansion from a small pilot to a continuing statewide programme. We included 363 California cities, allocated to early (n=187) or later (n=176) intervention in blocks stratified by region within the state, and within region by population and violent crime rate. The study period began 1 February 2015; region-specific end dates ranged from 1 May 2015 to 1 February 2016. Analysis was on an intention-to-treat, difference-in-difference basis using generalised linear mixed models and generalised estimating equations with robust SEs. The population-level primary outcome measures were monthly city-level counts of firearm-related homicides, robberies and aggravated assaults. The primary model was adjusted for stratification variables; city-level population, population density, socioeconomic status and firearm purchasing; year; and month. FINDINGS: Allocation groups were well balanced on baseline characteristics and implementation measures. In adjusted models, allocation to early intervention was not associated with statistically significant differences in any primary outcome measure; these findings were robust to multiple sensitivity analyses. There was some heterogeneity across regions. CONCLUSIONS: The APPS intervention directly affects a very small percentage of the population, limiting its potential for population-level effects. Individual-level analyses may provide a better estimate of the intervention's effectiveness. TRIAL REGISTRATION NUMBER: NCT02318732.
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INTRODUCTION: Well-chosen biomarkers have the potential to increase the efficiency of clinical trials and drug discovery and should show good precision as well as clinical validity. METHODS: We suggest measures that operationalize these criteria and describe a general approach that can be used for inference-based comparisons of biomarker performance. The methods are applied to measures obtained from structural magnetic resonance imaging (MRI) from individuals with mild dementia (n = 70) or mild cognitive impairment (MCI; n = 303) enrolled in the Alzheimer's Disease Neuroimaging Initiative. RESULTS: Ventricular volume and hippocampal volume showed the best precision in detecting change over time in both individuals with MCI and with dementia. Differences in clinical validity varied by group. DISCUSSION: The methodology presented provides a standardized framework for comparison of biomarkers across modalities and across different methods used to generate similar measures and will help in the search for the most promising biomarkers. HIGHLIGHTS: A framework for comparison of biomarkers on pre-defined criteria is presented. Criteria for comparison include precision in capturing change and clinical validity. Ventricular volume has high precision in change for both dementia and mild cognitive impairment (MCI) trials. Imaging measures' performance in clinical validity varies more for dementia than for MCI.
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Biomarcadores , Disfunção Cognitiva , Imageamento por Ressonância Magnética , Humanos , Imageamento por Ressonância Magnética/normas , Disfunção Cognitiva/diagnóstico , Idoso , Feminino , Masculino , Doença de Alzheimer/diagnóstico por imagem , Demência , Idoso de 80 Anos ou mais , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Ventrículos Cerebrais/diagnóstico por imagem , Ventrículos Cerebrais/patologiaRESUMO
The goal of the Biostatistics Core of the Alzheimer's Disease Neuroimaging Initiative (ADNI) has been to ensure that sound study designs and statistical methods are used to meet the overall goals of ADNI. We have supported the creation of a well-validated and well-curated longitudinal database of clinical and biomarker information on ADNI participants and helped to make this accessible and usable for researchers. We have developed a statistical methodology for characterizing the trajectories of clinical and biomarker change for ADNI participants across the spectrum from cognitively normal to dementia, including multivariate patterns and evidence for heterogeneity in cognitive aging. We have applied these methods and adapted them to improve clinical trial design. ADNI-4 will offer us a chance to help extend these efforts to a more diverse cohort with an even richer panel of biomarker data to support better knowledge of and treatment for Alzheimer's disease and related dementias. HIGHLIGHTS: The Alzheimer's Disease Neuroimaging Initiative (ADNI) Biostatistics Core provides study design and analytic support to ADNI investigators. Core members develop and apply novel statistical methodology to work with ADNI data and support clinical trial design. The Core contributes to the standardization, validation, and harmonization of biomarker data. The Core serves as a resource to the wider research community to address questions related to the data and study as a whole.
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Doença de Alzheimer , Bioestatística , Neuroimagem , Humanos , Doença de Alzheimer/diagnóstico por imagem , Neuroimagem/métodos , Bioestatística/métodos , Biomarcadores , Bases de Dados Factuais , Projetos de Pesquisa , Estudos Longitudinais , MasculinoRESUMO
The Alzheimer's Disease Neuroimaging Initiative (ADNI) aims to improve Alzheimer's disease (AD) clinical trials. Since 2006, ADNI has shared clinical, neuroimaging, and cognitive data, and biofluid samples. We used conventional search methods to identify 1459 publications from 2021 to 2022 using ADNI data/samples and reviewed 291 impactful studies. This review details how ADNI studies improved disease progression understanding and clinical trial efficiency. Advances in subject selection, detection of treatment effects, harmonization, and modeling improved clinical trials and plasma biomarkers like phosphorylated tau showed promise for clinical use. Biomarkers of amyloid beta, tau, neurodegeneration, inflammation, and others were prognostic with individualized prediction algorithms available online. Studies supported the amyloid cascade, emphasized the importance of neuroinflammation, and detailed widespread heterogeneity in disease, linked to genetic and vascular risk, co-pathologies, sex, and resilience. Biological subtypes were consistently observed. Generalizability of ADNI results is limited by lack of cohort diversity, an issue ADNI-4 aims to address by enrolling a diverse cohort.
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Doença de Alzheimer , Disfunção Cognitiva , Humanos , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/terapia , Peptídeos beta-Amiloides , Neuroimagem/métodos , Biomarcadores , Progressão da Doença , Proteínas tau , Disfunção Cognitiva/diagnóstico por imagemRESUMO
INTRODUCTION: We evaluated preliminary feasibility of a digital, culturally-informed approach to recruit and screen participants for the Alzheimer's Disease Neuroimaging Initiative (ADNI4). METHODS: Participants were recruited using digital advertising and completed digital surveys (e.g., demographics, medical exclusion criteria, 12-item Everyday Cognition Scale [ECog-12]), Novoic Storyteller speech-based cognitive test). Completion rates and assessment performance were compared between underrepresented populations (URPs: individuals from ethnoculturally minoritized or low education backgrounds) and non-URPs. RESULTS: Of 3099 participants who provided contact information, 654 enrolled in the cohort, and 595 completed at least one assessment. Two hundred forty-seven participants were from URPs. Of those enrolled, 465 met ADNI4 inclusion criteria and 237 evidenced possible cognitive impairment from ECog-12 or Storyteller performance. URPs had lower ECog and Storyteller completion rates. Scores varied by ethnocultural group and educational level. DISCUSSION: Preliminary results demonstrate digital recruitment and screening assessment of an older diverse cohort, including those with possible cognitive impairment, are feasible. Improving engagement and achieving educational diversity are key challenges. HIGHLIGHTS: A total of 654 participants enrolled in a digital cohort to facilitate ADNI4 recruitment. Culturally-informed digital ads aided enrollment of underrepresented populations. From those enrolled, 42% were from underrepresented ethnocultural and educational groups. Digital screening tools indicate > 50% of participants likely cognitively impaired. Completion rates and assessment performance vary by ethnocultural group and education.
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Doença de Alzheimer , Seleção de Pacientes , Humanos , Doença de Alzheimer/diagnóstico , Masculino , Feminino , Idoso , Disfunção Cognitiva/diagnóstico , Testes Neuropsicológicos/estatística & dados numéricos , Neuroimagem , Estudos de Viabilidade , Idoso de 80 Anos ou mais , Estudos de Coortes , Inquéritos e QuestionáriosRESUMO
The extent to which the pathophysiology of autosomal dominant Alzheimer's disease corresponds to the pathophysiology of 'sporadic' late onset Alzheimer's disease is unknown, thus limiting the extrapolation of study findings and clinical trial results in autosomal dominant Alzheimer's disease to late onset Alzheimer's disease. We compared brain MRI and amyloid PET data, as well as CSF concentrations of amyloid-ß42, amyloid-ß40, tau and tau phosphorylated at position 181, in 292 carriers of pathogenic variants for Alzheimer's disease from the Dominantly Inherited Alzheimer Network, with corresponding data from 559 participants from the Alzheimer's Disease Neuroimaging Initiative. Imaging data and CSF samples were reprocessed as appropriate to guarantee uniform pipelines and assays. Data analyses yielded rates of change before and after symptomatic onset of Alzheimer's disease, allowing the alignment of the â¼30-year age difference between the cohorts on a clinically meaningful anchor point, namely the participant age at symptomatic onset. Biomarker profiles were similar for both autosomal dominant Alzheimer's disease and late onset Alzheimer's disease. Both groups demonstrated accelerated rates of decline in cognitive performance and in regional brain volume loss after symptomatic onset. Although amyloid burden accumulation as determined by PET was greater after symptomatic onset in autosomal dominant Alzheimer's disease than in late onset Alzheimer's disease participants, CSF assays of amyloid-ß42, amyloid-ß40, tau and p-tau181 were largely overlapping in both groups. Rates of change in cognitive performance and hippocampal volume loss after symptomatic onset were more aggressive for autosomal dominant Alzheimer's disease participants. These findings suggest a similar pathophysiology of autosomal dominant Alzheimer's disease and late onset Alzheimer's disease, supporting a shared pathobiological construct.
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Doença de Alzheimer , Amiloidose , Humanos , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/genética , Peptídeos beta-Amiloides , Imageamento por Ressonância Magnética/métodos , BiomarcadoresRESUMO
INTRODUCTION: The Alzheimer's Disease Neuroimaging Initiative (ADNI) aims to validate biomarkers for Alzheimer's disease (AD) clinical trials. To improve generalizability, ADNI4 aims to enroll 50-60% of its new participants from underrepresented populations (URPs) using new biofluid and digital technologies. ADNI4 has received funding from the National Institute on Aging beginning September 2022. METHODS: ADNI4 will recruit URPs using community-engaged approaches. An online portal will screen 20,000 participants, 4000 of whom (50-60% URPs) will be tested for plasma biomarkers and APOE. From this, 500 new participants will undergo in-clinic assessment joining 500 ADNI3 rollover participants. Remaining participants (â¼3500) will undergo longitudinal plasma and digital cognitive testing. ADNI4 will add MRI sequences and new PET tracers. Project 1 will optimize biomarkers in AD clinical trials. RESULTS AND DISCUSSION: ADNI4 will improve generalizability of results, use remote digital and blood screening, and continue providing longitudinal clinical, biomarker, and autopsy data to investigators.
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Doença de Alzheimer , Disfunção Cognitiva , Humanos , Doença de Alzheimer/diagnóstico por imagem , Participação da Comunidade , Participação dos Interessados , Neuroimagem/métodos , Biomarcadores , Disfunção Cognitiva/diagnóstico por imagem , Peptídeos beta-AmiloidesRESUMO
INTRODUCTION: Magnetic resonance imaging (MRI) research has advanced our understanding of neurodegeneration in sporadic early-onset Alzheimer's disease (EOAD) but studies include small samples, mostly amnestic EOAD, and have not focused on developing an MRI biomarker. METHODS: We analyzed MRI scans to define the sporadic EOAD-signature atrophy in a small sample (n = 25) of Massachusetts General Hospital (MGH) EOAD patients, investigated its reproducibility in the large longitudinal early-onset Alzheimer's disease study (LEADS) sample (n = 211), and investigated the relationship of the magnitude of atrophy with cognitive impairment. RESULTS: The EOAD-signature atrophy was replicated across the two cohorts, with prominent atrophy in the caudal lateral temporal cortex, inferior parietal lobule, and posterior cingulate and precuneus cortices, and with relative sparing of the medial temporal lobe. The magnitude of EOAD-signature atrophy was associated with the severity of cognitive impairment. DISCUSSION: The EOAD-signature atrophy is a reliable and clinically valid biomarker of AD-related neurodegeneration that could be used in clinical trials for EOAD. HIGHLIGHTS: We developed an early-onset Alzheimer's disease (EOAD)-signature of atrophy based on magnetic resonance imaging (MRI) scans. EOAD signature was robustly reproducible across two independent patient cohorts. EOAD signature included prominent atrophy in parietal and posterior temporal cortex. The EOAD-signature atrophy was associated with the severity of cognitive impairment. EOAD signature is a reliable and clinically valid biomarker of neurodegeneration.
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Doença de Alzheimer , Humanos , Doença de Alzheimer/patologia , Reprodutibilidade dos Testes , Lobo Temporal/patologia , Imageamento por Ressonância Magnética/métodos , Atrofia/patologia , BiomarcadoresRESUMO
INTRODUCTION: One goal of the Longitudinal Early-onset Alzheimer's Disease Study (LEADS) is to investigate the genetic etiology of early onset (40-64 years) cognitive impairment. Toward this goal, LEADS participants are screened for known pathogenic variants. METHODS: LEADS amyloid-positive early-onset Alzheimer's disease (EOAD) or negative early-onset non-AD (EOnonAD) cases were whole exome sequenced (N = 299). Pathogenic variant frequency in APP, PSEN1, PSEN2, GRN, MAPT, and C9ORF72 was assessed for EOAD and EOnonAD. Gene burden testing was performed in cases compared to similar-age cognitively normal controls in the Parkinson's Progression Markers Initiative (PPMI) study. RESULTS: Previously reported pathogenic variants in the six genes were identified in 1.35% of EOAD (3/223) and 6.58% of EOnonAD (5/76). No genes showed enrichment for carriers of rare functional variants in LEADS cases. DISCUSSION: Results suggest that LEADS is enriched for novel genetic causative variants, as previously reported variants are not observed in most cases. HIGHLIGHTS: Sequencing identified eight cognitively impaired pathogenic variant carriers. Pathogenic variants were identified in PSEN1, GRN, MAPT, and C9ORF72. Rare variants were not enriched in APP, PSEN1/2, GRN, and MAPT. The Longitudinal Early-onset Alzheimer's Disease Study (LEADS) is a key resource for early-onset Alzheimer's genetic research.
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Doença de Alzheimer , Humanos , Doença de Alzheimer/genética , Precursor de Proteína beta-Amiloide/genética , Proteína C9orf72/genética , Testes Genéticos , Estudos Longitudinais , Mutação , Presenilina-1/genética , Presenilina-2/genéticaRESUMO
INTRODUCTION: We examined neuropsychiatric symptoms (NPS) and psychotropic medication use in a large sample of individuals with early-onset Alzheimer's disease (EOAD; onset 40-64 years) at the midway point of data collection for the Longitudinal Early-onset Alzheimer's Disease Study (LEADS). METHODS: Baseline NPS (Neuropsychiatric Inventory - Questionnaire; Geriatric Depression Scale) and psychotropic medication use from 282 participants enrolled in LEADS were compared across diagnostic groups - amyloid-positive EOAD (n = 212) and amyloid negative early-onset non-Alzheimer's disease (EOnonAD; n = 70). RESULTS: Affective behaviors were the most common NPS in EOAD at similar frequencies to EOnonAD. Tension and impulse control behaviors were more common in EOnonAD. A minority of participants were using psychotropic medications, and use was higher in EOnonAD. DISCUSSION: Overall NPS burden and psychotropic medication use were higher in EOnonAD than EOAD participants. Future research will investigate moderators and etiological drivers of NPS, and NPS differences in EOAD versus late-onset AD.
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Doença de Alzheimer , Humanos , Idoso , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/psicologia , Estudos Longitudinais , Coleta de DadosRESUMO
INTRODUCTION: We compared white matter hyperintensities (WMHs) in early-onset Alzheimer's disease (EOAD) with cognitively normal (CN) and early-onset amyloid-negative cognitively impaired (EOnonAD) groups in the Longitudinal Early-Onset Alzheimer's Disease Study. METHODS: We investigated the role of increased WMH in cognition and amyloid and tau burden. We compared WMH burden of 205 EOAD, 68 EOnonAD, and 89 CN participants in lobar regions using t-tests and analyses of covariance. Linear regression analyses were used to investigate the association between WMH and cognitive impairment and that between amyloid and tau burden. RESULTS: EOAD showed greater WMHs compared with CN and EOnonAD participants across all regions with no significant differences between CN and EOnonAD groups. Greater WMHs were associated with worse cognition. Tau burden was positively associated with WMH burden in the EOAD group. DISCUSSION: EOAD consistently showed higher WMH volumes. Overall, greater WMHs were associated with worse cognition and higher tau burden in EOAD. HIGHLIGHTS: This study represents a comprehensive characterization of WMHs in sporadic EOAD. WMH volumes are associated with tau burden from positron emission tomography (PET) in EOAD, suggesting WMHs are correlated with increasing burden of AD. Greater WMH volumes are associated with worse performance on global cognitive tests. EOAD participants have higher WMH volumes compared with CN and early-onset amyloid-negative cognitively impaired (EOnonAD) groups across all brain regions.
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Doença de Alzheimer , Disfunção Cognitiva , Substância Branca , Humanos , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/complicações , Substância Branca/diagnóstico por imagem , Substância Branca/metabolismo , Peptídeos beta-Amiloides/metabolismo , Proteínas tau/metabolismo , Imageamento por Ressonância Magnética , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/complicações , Proteínas Amiloidogênicas , AmiloideRESUMO
INTRODUCTION: One goal of the Longitudinal Early Onset Alzheimer's Disease Study (LEADS) is to define the fluid biomarker characteristics of early-onset Alzheimer's disease (EOAD). METHODS: Cerebrospinal fluid (CSF) concentrations of Aß1-40, Aß1-42, total tau (tTau), pTau181, VILIP-1, SNAP-25, neurogranin (Ng), neurofilament light chain (NfL), and YKL-40 were measured by immunoassay in 165 LEADS participants. The associations of biomarker concentrations with diagnostic group and standard cognitive tests were evaluated. RESULTS: Biomarkers were correlated with one another. Levels of CSF Aß42/40, pTau181, tTau, SNAP-25, and Ng in EOAD differed significantly from cognitively normal and early-onset non-AD dementia; NfL, YKL-40, and VILIP-1 did not. Across groups, all biomarkers except SNAP-25 were correlated with cognition. Within the EOAD group, Aß42/40, NfL, Ng, and SNAP-25 were correlated with at least one cognitive measure. DISCUSSION: This study provides a comprehensive analysis of CSF biomarkers in sporadic EOAD that can inform EOAD clinical trial design.
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Doença de Alzheimer , Humanos , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/líquido cefalorraquidiano , Proteína 1 Semelhante à Quitinase-3 , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Proteínas tau/líquido cefalorraquidiano , Estudos Longitudinais , Biomarcadores/líquido cefalorraquidiano , Neurogranina/líquido cefalorraquidianoRESUMO
OBJECTIVE: The Longitudinal Early-Onset Alzheimer's Disease Study (LEADS) seeks to provide comprehensive understanding of early-onset Alzheimer's disease (EOAD; onset <65 years), with the current study profiling baseline clinical, cognitive, biomarker, and genetic characteristics of the cohort nearing the data-collection mid-point. METHODS: Data from 371 LEADS participants were compared based on diagnostic group classification (cognitively normal [n = 89], amyloid-positive EOAD [n = 212], and amyloid-negative early-onset non-Alzheimer's disease [EOnonAD; n = 70]). RESULTS: Cognitive performance was worse for EOAD than other groups, and EOAD participants were apolipoprotein E (APOE) ε4 homozygotes at higher rates. An amnestic presentation was common among impaired participants (81%), with several clinical phenotypes present. LEADS participants generally consented at high rates to optional trial procedures. CONCLUSIONS: We present the most comprehensive baseline characterization of sporadic EOAD in the United States to date. EOAD presents with widespread cognitive impairment within and across clinical phenotypes, with differences in APOE ε4 allele carrier status appearing to be relevant. HIGHLIGHTS: Findings represent the most comprehensive baseline characterization of sporadic early-onset Alzheimer's disease (EOAD) to date. Cognitive impairment was widespread for EOAD participants and more severe than other groups. EOAD participants were homozygous apolipoprotein E (APOE) ε4 carriers at higher rates than the EOnonAD group. Amnestic presentation predominated in EOAD and EOnonAD participants, but other clinical phenotypes were present.
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Doença de Alzheimer , Humanos , Doença de Alzheimer/genética , Doença de Alzheimer/psicologia , Apolipoproteínas E/genética , Estudos Longitudinais , Apolipoproteína E4/genética , Coleta de DadosRESUMO
INTRODUCTION: The Alzheimer's Disease Neuroimaging Initiative (ADNI) has accumulated 15 years of clinical, neuroimaging, cognitive, biofluid biomarker and genetic data, and biofluid samples available to researchers, resulting in more than 3500 publications. This review covers studies from 2018 to 2020. METHODS: We identified 1442 publications using ADNI data by conventional search methods and selected impactful studies for inclusion. RESULTS: Disease progression studies supported pivotal roles for regional amyloid beta (Aß) and tau deposition, and identified underlying genetic contributions to Alzheimer's disease (AD). Vascular disease, immune response, inflammation, resilience, and sex modulated disease course. Biologically coherent subgroups were identified at all clinical stages. Practical algorithms and methodological changes improved determination of Aß status. Plasma Aß, phosphorylated tau181, and neurofilament light were promising noninvasive biomarkers. Prognostic and diagnostic models were externally validated in ADNI but studies are limited by lack of ethnocultural cohort diversity. DISCUSSION: ADNI has had a profound impact in improving clinical trials for AD.
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Doença de Alzheimer , Disfunção Cognitiva , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/genética , Peptídeos beta-Amiloides , Biomarcadores , Progressão da Doença , Humanos , Neuroimagem/métodos , Proteínas tauRESUMO
BACKGROUND: A substantial proportion of individuals who lawfully purchase firearms later become unlawful owners ('prohibited firearm owners'), usually following events associated with an increased risk for future violence. This high-risk population has not previously been described. We aimed to characterise all individuals in California's Armed and Prohibited Persons System (APPS), a statewide programme for recovering firearms from individuals who legally purchased them and later became prohibited from ownership. METHODS: We used univariate and bivariate statistics to describe and compare prohibited firearm owners in APPS with a random sample of non-prohibited firearm owners in relation to age, sex, race/ethnicity and type of firearms owned as of 1 February 2015. We also characterised the geographical distribution of prohibited firearm owners and described their prohibitions. RESULTS: Of the 18 976 prohibited firearm owners, most were men (93%), half were white (53%) and the mean age was 47 years. Prohibited firearm owners were more likely to be male and to be black or Hispanic people than non-prohibited owners. Both prohibited and non-prohibited firearm owners had an average of 2.6 firearms, mostly handguns. Nearly half (48%) of prohibited firearm owners had a felony conviction. Extrapolating from our findings, we estimated that there are approximately 100 000 persons in the USA who unlawfully maintained ownership of their firearms following a felony conviction. CONCLUSIONS: Retention of firearms among persons who become lawfully prohibited from possessing them is common in California. Given the nationwide dearth of a programme to recover such weapons, this is likely true in other states as well.
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Armas de Fogo , Comportamento do Consumidor , Crime , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Propriedade , ViolênciaRESUMO
PURPOSE: To demonstrate that constant coefficient of variation (CV), but nonconstant absolute variance in MRI relaxometry (T1 , T2 , R1 , R2 ) data leads to erroneous conclusions based on standard linear models such as ordinary least squares (OLS). We propose a gamma generalized linear model identity link (GGLM-ID) framework that factors the inherent CV into parameter estimates. We first examined the effects on calculations of contrast agent relaxivity before broadening to other applications such as analysis of variance (ANOVA) and liver iron content (LIC). METHODS: Eight models including OLS and GGLM-ID were initially fit to data obtained on sulfated dextran iron oxide (SDIO) nanoparticles. Both a resampling simulation on the data as well as two separate Monte Carlo simulations (with and without concentration error) were performed to determine mean square error (MSE) and type I error rate. We then evaluated the performance of OLS/GGLM-ID on R1 repeatability and LIC data sets. RESULTS: OLS had an MSE of 4-5× that of GGLM-ID as well as a type I error rate of 20-30%, whereas GGLM-ID was near the nominal 5% level in the relaxivity study. Only OLS found statistically significant effects of MRI facility on relaxivity in an R1 repeatability study, but no significant differences were found in a resampling, whereas GGLM was more consistent. GGLM-ID was also superior to OLS for modeling LIC. CONCLUSIONS: OLS leads to erroneous conclusions when analyzing MRI relaxometry data. GGLM-ID factors in the inherent CV of an MRI experiment, leading to more reproducible conclusions.
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Sobrecarga de Ferro , Imageamento por Ressonância Magnética , Meios de Contraste , Humanos , Ferro , FígadoRESUMO
Neuroblastoma (NB) is the most common extracranial solid tumor in children. The outcomes for aggressive forms of NB remain poor. The aim of this study was to develop a new molecular-targeted therapy for NB using an antisense oligonucleotide (ASO) and superparamagnetic iron oxide (SPIO) nanoparticles (NPs), as a delivery vehicle, targeting the transcription regulator MAX dimerization protein 3 (MXD3). We previously discovered that MXD3 was highly expressed in high-risk NB, acting as an anti-apoptotic factor; therefore, it can be a good therapeutic target. In this study, we developed two ASO-NP complexes using electrostatic conjugation to polyethylenimine-coated SPIO NPs and chemical conjugation to amphiphilic polymers on amine-functionalized SPIO NPs. Both ASO-NP complexes demonstrated MXD3 knockdown, which resulted in apoptosis in NB cells. ASO chemically-conjugated NP complexes have the potential to be used in the clinic as they showed great efficacy with minimum NP-associated cytotoxicity.
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Compostos Férricos/química , Compostos Férricos/farmacologia , Nanopartículas de Magnetita/química , Nanopartículas Metálicas/química , Oligonucleotídeos Antissenso/química , Oligonucleotídeos Antissenso/farmacologia , Proteínas Repressoras/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular Tumoral , Inativação Gênica/fisiologia , Humanos , Immunoblotting , Imuno-Histoquímica , Neuroblastoma/genética , Neuroblastoma/metabolismo , Proteínas Repressoras/genética , Eletricidade EstáticaRESUMO
BACKGROUND: Previous studies have shown that individuals overestimate the success of cardiopulmonary resuscitation (CPR) while underestimating its morbidity. Although perceptions of CPR success affect medical care in the emergency department (ED), no ED-based studies have been done. OBJECTIVE: To survey ED patients and their companions to assess their expectations, hypothesising that variation in information sources, prior exposure to CPR, and healthcare experience would influence predicted CPR success rates. METHODS: A survey was carried out of adults (age >18 years) in the ED waiting area of a tertiary care hospital between June and September 2016. An optimism scale was created to reflect expected likelihood of survival after CPR, or CPR success, under several sets of circumstances. Potential predictors of optimism for CPR outcome were examined using linear regression. Associations between optimism and CPR preference were evaluated using a Wilcoxon rank-sum test. RESULTS: There were 500 respondents and 53% had performed or witnessed CPR, and/or participated in a CPR course (64%). Television was the main source of information about CPR for >95% of respondents. At least half (51-64%) of respondents estimated the success rate of CPR as over 75% in all situations. Estimated CPR success rates were unrelated to age, sex, race, spiritual beliefs or personal healthcare experience. More than 90% of respondents wanted to receive CPR. Less than one-third of respondents had discussed CPR with a medical provider, but most wished to do so. CONCLUSION: Consistent with prior studies, individuals overestimate the success rate of CPR. Healthcare experience does not appear to mitigate optimism about CPR, and individuals overwhelmingly want CPR for themselves. Though few had talked about CPR with a medical provider, most wanted to have informed decision-making conversations. Such discussions could help patients obtain a more realistic view of CPR outcomes.
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Reanimação Cardiopulmonar/métodos , Serviço Hospitalar de Emergência , Preferência do Paciente , Adulto , California , Tomada de Decisões , Feminino , Humanos , Masculino , Estudos Prospectivos , Inquéritos e Questionários , Centros de Atenção TerciáriaRESUMO
INTRODUCTION: The overall goal of the Alzheimer's Disease Neuroimaging Initiative (ADNI) is to validate biomarkers for Alzheimer's disease (AD) clinical trials. ADNI is a multisite, longitudinal, observational study that has collected many biomarkers since 2004. Recent publications highlight the multifactorial nature of late-onset AD. We discuss selected topics that provide insights into AD progression and outline how this knowledge may improve clinical trials. METHODS: We used standard methods to identify nearly 600 publications using ADNI data from 2016 and 2017 (listed in Supplementary Material and searchable at http://adni.loni.usc.edu/news-publications/publications/). RESULTS: (1) Data-driven AD progression models supported multifactorial interactions rather than a linear cascade of events. (2) ß-Amyloid (Aß) deposition occurred concurrently with functional connectivity changes within the default mode network in preclinical subjects and was followed by specific and progressive disconnection of functional and anatomical networks. (3) Changes in functional connectivity, volumetric measures, regional hypometabolism, and cognition were detectable at subthreshold levels of Aß deposition. 4. Tau positron emission tomography imaging studies detailed a specific temporal and spatial pattern of tau pathology dependent on prior Aß deposition, and related to subsequent cognitive decline. 5. Clustering studies using a wide range of modalities consistently identified a "typical AD" subgroup and a second subgroup characterized by executive impairment and widespread cortical atrophy in preclinical and prodromal subjects. 6. Vascular pathology burden may act through both Aß dependent and independent mechanisms to exacerbate AD progression. 7. The APOE ε4 allele interacted with cerebrovascular disease to impede Aß clearance mechanisms. 8. Genetic approaches identified novel genetic risk factors involving a wide range of processes, and demonstrated shared genetic risk for AD and vascular disorders, as well as the temporal and regional pathological associations of established AD risk alleles. 9. Knowledge of early pathological changes guided the development of novel prognostic biomarkers for preclinical subjects. 10. Placebo populations of randomized controlled clinical trials had highly variable trajectories of cognitive change, underscoring the importance of subject selection and monitoring. 11. Selection criteria based on Aß positivity, hippocampal volume, baseline cognitive/functional measures, and APOE ε4 status in combination with improved cognitive outcome measures were projected to decrease clinical trial duration and cost. 12. Multiple concurrent therapies targeting vascular health and other AD pathology in addition to Aß may be more effective than single therapies. DISCUSSION: ADNI publications from 2016 and 2017 supported the idea of AD as a multifactorial disease and provided insights into the complexities of AD disease progression. These findings guided the development of novel biomarkers and suggested that subject selection on the basis of multiple factors may lower AD clinical trial costs and duration. The use of multiple concurrent therapies in these trials may prove more effective in reversing AD disease progression.