scholarly journals Association of Odor Identification Ability With Amyloid-β and Tau Burden: A Systematic Review and Meta-Analysis

2020 ◽  
Vol 14 ◽  
Author(s):  
Lihui Tu ◽  
Xiaozhen Lv ◽  
Zili Fan ◽  
Ming Zhang ◽  
Huali Wang ◽  
...  
Keyword(s):  
Subgroup Analysis ◽  
Meta Analysis ◽  
Pearson Correlation ◽  
Amyloid Β ◽  
Correlation Coefficients ◽  
Current Evidence ◽  
Csf Biomarkers ◽  
Mild Cognitive Impairment Group ◽  
Positron Emission ◽  
Tau Pet

Background: The associations between olfactory identification (OI) ability and the Alzheimer's disease biomarkers were not clear.Objective: This meta-analysis aimed to examine the associations between OI and Aβ and tau burden.Methods: Electronic databases (PubMed, Embase, PsycINFO, and Google Scholar) were searched until June 2019 to identify studies that reported correlation coefficients or regression coefficients between OI and Aβ or tau levels measured by positron emission tomography (PET) or cerebrospinal fluid (CSF). Pooled Pearson correlation coefficients were computed for the PET imaging and CSF biomarkers, with subgroup analysis for subjects classified into different groups.Results: Nine studies met the inclusion criteria. Of these, five studies (N = 494) involved Aβ PET, one involved tau PET (N = 26), and four involved CSF Aβ or tau (N = 345). OI was negatively associated with Aβ PET in the mixed (r = −0.25, P = 0.008) and cognitively normal groups (r = −0.15, P = 0.004) but not in the mild cognitive impairment group. A similar association with CSF total tau in the mixed group was also observed. No association was found between OI and CSF phosphorylated tau or Aβ42 in the subgroup analysis of the CSF biomarkers. Due to a lack of data, no pooled r value could be computed for the association between the OI and tau PET.Conclusion: The associations between OI ability and Aβ and CSF tau burden in older adults are negligible. While current evidence does not support the association, further studies using PET tau imaging are warranted.

scholarly journals Cerebrospinal Fluid Biomarkers of Alzheimer’s Disease: Current Evidence and Future Perspectives

2021 ◽  
Vol 11 (2) ◽  
pp. 215
Author(s):  
Donovan A. McGrowder ◽  
Fabian Miller ◽  
Kurt Vaz ◽  
Chukwuemeka Nwokocha ◽  
Cameil Wilson-Clarke ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cerebrospinal Fluid ◽  
Late Onset ◽  
Amyloid Β ◽  
Current Evidence ◽  
Csf Biomarkers ◽  
Diagnostic Efficacy ◽  
Neurofilament Light ◽  
New Biomarkers

Alzheimer’s disease is a progressive, clinically heterogeneous, and particularly complex neurodegenerative disease characterized by a decline in cognition. Over the last two decades, there has been significant growth in the investigation of cerebrospinal fluid (CSF) biomarkers for Alzheimer’s disease. This review presents current evidence from many clinical neurochemical studies, with findings that attest to the efficacy of existing core CSF biomarkers such as total tau, phosphorylated tau, and amyloid-β (Aβ42), which diagnose Alzheimer’s disease in the early and dementia stages of the disorder. The heterogeneity of the pathophysiology of the late-onset disease warrants the growth of the Alzheimer’s disease CSF biomarker toolbox; more biomarkers showing other aspects of the disease mechanism are needed. This review focuses on new biomarkers that track Alzheimer’s disease pathology, such as those that assess neuronal injury (VILIP-1 and neurofilament light), neuroinflammation (sTREM2, YKL-40, osteopontin, GFAP, progranulin, and MCP-1), synaptic dysfunction (SNAP-25 and GAP-43), vascular dysregulation (hFABP), as well as CSF α-synuclein levels and TDP-43 pathology. Some of these biomarkers are promising candidates as they are specific and predict future rates of cognitive decline. Findings from the combinations of subclasses of new Alzheimer’s disease biomarkers that improve their diagnostic efficacy in detecting associated pathological changes are also presented.

scholarly journals Association of amyloid-β CSF/PET discordance and tau load 5 years later

Neurology ◽  
2020 ◽  
Vol 95 (19) ◽  
pp. e2648-e2657 ◽  
Author(s):  
Juhan Reimand ◽  
Lyduine Collij ◽  
Philip Scheltens ◽  
Femke Bouwman ◽  
Rik Ossenkoppele ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Amyloid Β ◽  
Csf Biomarkers ◽  
Tau Pathology ◽  
Cognitively Normal ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Tau Pet

ObjectiveTo investigate the association between discordant β-amyloid (Aβ) PET and CSF biomarkers at baseline and the emergence of tau pathology 5 years later.MethodsWe included 730 Alzheimer's Disease Neuroimaging Initiative (ADNI) participants without dementia (282 cognitively normal, 448 mild cognitive impairment) with baseline [18F]florbetapir PET and CSF Aβ42 available. Aβ CSF/PET status was determined at baseline using established cutoffs. Longitudinal data were available for [18F]florbetapir (Aβ) PET (baseline to 4.3 ± 1.9 years), CSF (p)tau (baseline to 2.0 ± 0.1 years), cognition (baseline to 4.3 ± 2.0 years), and [18F]flortaucipir (tau) PET (measured 5.2 ± 1.2 years after baseline to 1.6 ± 0.7 years later). We used linear mixed modeling to study the association between Aβ CSF/PET status and tau pathology measured in CSF or using PET. We calculated the proportion of CSF+/PET− participants who during follow-up (1) progressed to Aβ CSF+/PET+ or (2) became tau-positive based on [18F]flortaucipir PET.ResultsAβ CSF+/PET+ (n = 318) participants had elevated CSF (p)tau levels and worse cognitive performance at baseline, while CSF+/PET− (n = 80) participants were overall similar to the CSF−/PET− (N = 306) group. Five years after baseline, [18F]flortaucipir PET uptake in the CSF+/PET− group (1.20 ± 0.13) did not differ from CSF−/PET− (1.18 ± 0.08, p = 0.69), but was substantially lower than CSF+/PET+ (1.48 ± 0.44, p < 0.001). Of the CSF+/PET− participants, 21/64 (33%) progressed to Aβ CSF+/PET+, whereas only one (3%, difference p < 0.05) became tau-positive based on [18F]flortaucipir PET.ConclusionsAβ load detectable by both CSF and PET seems to precede substantial tau deposition. Compared to participants with abnormal Aβ levels on both PET and CSF, the CSF+/PET− group has a distinctly better prognosis.

scholarly journals Association between the TACC3 rs798766 Polymorphism and Risk of Urinary Bladder Cancer: A Synthesis Based on Current Evidence

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Xiang-Yu Meng ◽  
Ming-Jun Shi ◽  
Jia-Feng Chen ◽  
Yi Liao ◽  
Bang-Wang Hu ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Urinary Bladder ◽  
Subgroup Analysis ◽  
Meta Analysis ◽  
Population Attributable Risk ◽  
Urinary Bladder Cancer ◽  
Current Evidence ◽  
Bladder Cancer Risk ◽  
Search Terms ◽  
Increased Risk

Background. A possible association between the TACC3 rs798766 polymorphism and urinary bladder cancer risk has been indicated in published literature. We performed this meta-analysis as a synthesis of all relevant data to summarize currently available evidence and to provide estimation with increased precision. Methods. EMBASE, PubMed, Google Scholar, and Wanfang Data were searched. “rs798766” and “urinary bladder cancer” were used as the search terms. A total of 6 eligible studies were identified, in which 8194 cases and 50,165 controls were investigated. Meta-analysis was performed using extracted data. Subgroup analysis by ethnicity was also performed. Population attributable risk (PAR) was calculated. Results. We found a significant association between rs798766[T] and increased risk of bladder cancer, allelic[T] OR=1.27, 95%CI=1.20–1.33. Subgroup analysis by ethnicity revealed similar results, allelic[T] OR=1.24, 95%CI=1.17–1.32 in Caucasian subjects and allelic[T] OR=1.33, 95%CI=1.21–1.46 in Asian subjects. PAR based on pooled allelic ORs and the frequency of the risk allele in control subjects was 4.63% in the overall population and 3.92% in Asians and 4.36% in Caucasians. Conclusion. rs798766 is associated with increased risk of bladder cancer, and no ethnic difference was found.

scholarly journals Longitudinal Observation of Early-Onset Alzheimer’s Disease Dementia with Positive CSF Biomarkers/Negative Amyloid-β Positron-Emission Tomography

2021 ◽  
Vol 39 (3) ◽  
pp. 214-218
Author(s):  
Min Hye Kim ◽  
Joonho Lee ◽  
Hong Nam Kim ◽  
In Ja Shin ◽  
Keun Lee ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Positron Emission Tomography ◽  
Early Onset ◽  
Brain Magnetic Resonance Imaging ◽  
Amyloid Β ◽  
Emission Tomography ◽  
Csf Biomarkers ◽  
Amyloid Pet ◽  
Positron Emission

We report a 61-year-old woman with clinical course for Alzheimer’s disease (AD) dementia and discordant amyloid-β positron-emission tomography (PET) and cerebrospinal fluid biomarkers. Brain magnetic resonance imaging revealed remarkable atrophy in the hippocampus. However, repeated delayed <sup>18</sup>F-flutemetamol brain amyloid PET images with 1 year-interval revealed no amyloid deposition, whereas her CSF revealed low Aβ42, high total tau and p-tau181. This discordant amyloid-β PET and CSF biomarkers in this early-onset AD dementia might be associated with her low resilience or mixed pathology.

scholarly journals Characterization of Alzheimer’s tau biomarker discordance using plasma, CSF, and PET

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yu Guo ◽  
◽  
Yu-Yuan Huang ◽  
Xue-Ning Shen ◽  
Shi-Dong Chen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Decline ◽  
Amyloid Β ◽  
Regions Of Interest ◽  
Emission Tomography ◽  
Braak Stage ◽  
Positron Emission ◽  
Tau Pet

Abstract Background We aimed to investigate the tau biomarker discrepancies of Alzheimer’s disease (AD) using plasma tau phosphorylated at threonine 181 (p-tau181), cerebrospinal fluid (CSF) p-tau181, and AV1451 positron emission tomography (PET). Methods In the Alzheimer’s Disease Neuroimaging Initiative, 724 non-demented participants were categorized into plasma/CSF and plasma/PET groups. Demographic and clinical variables, amyloid-β (Aβ) burden, flortaucipir-PET binding in Braak regions of interest (ROIs), longitudinal changes in clinical outcomes, and conversion risk were compared. Results Across different tau biomarker groups, the proportion of participants with a discordant profile varied (plasma+/CSF− 15.6%, plasma−/CSF+ 15.3%, plasma+/PET− 22.4%, and plasma−/PET+ 6.1%). Within the plasma/CSF categories, we found an increase from concordant-negative to discordant to concordant-positive in the frequency of Aβ pathology or cognitive impairment, rates of cognitive decline, and risk of cognitive conversion. However, the two discordant categories (plasma+/CSF− and plasma−/CSF+) showed comparable performances, resulting in similarly reduced cognitive capacities. Regarding plasma/PET categories, as expected, PET-positive individuals had increased Aβ burden, elevated flortaucipir retention in Braak ROIs, and accelerated cognitive deterioration than concordant-negative persons. Noteworthy, discordant participants with normal PET exhibited reduced flortaucipir uptake in Braak stage ROIs and slower rates of cognitive decline, relative to those PET-positive. Therefore, individuals with PET abnormality appeared to have advanced tau pathological changes and poorer cognitive function, regardless of the plasma status. Furthermore, these results were found only in individuals with Aβ pathology. Conclusions Our results indicate that plasma and CSF p-tau181 abnormalities associated with amyloidosis occur simultaneously in the progression of AD pathogenesis and related cognitive decline, before tau-PET turns positive.

scholarly journals The validation status of blood biomarkers of amyloid and phospho-tau assessed with the 5-phase development framework for AD biomarkers

2021 ◽  
Author(s):  
N. J. Ashton ◽  
A. Leuzy ◽  
T. K. Karikari ◽  
N. Mattsson-Carlgren ◽  
A. Dodich ◽  
...  
Keyword(s):  
Amyloid Β ◽  
Preliminary Evidence ◽  
Csf Biomarkers ◽  
Phase 2 ◽  
Blood Biomarkers ◽  
Phase 3 ◽  
Development Framework ◽  
Positron Emission ◽  
Phase Development ◽  
Impact Cost

Abstract Purpose The development of blood biomarkers that reflect Alzheimer’s disease (AD) pathophysiology (phosphorylated tau and amyloid-β) has offered potential as scalable tests for dementia differential diagnosis and early detection. In 2019, the Geneva AD Biomarker Roadmap Initiative included blood biomarkers in the systematic validation of AD biomarkers. Methods A panel of experts convened in November 2019 at a two-day workshop in Geneva. The level of maturity (fully achieved, partly achieved, preliminary evidence, not achieved, unsuccessful) of blood biomarkers was assessed based on the Biomarker Roadmap methodology and discussed fully during the workshop which also evaluated cerebrospinal fluid (CSF) and positron emission tomography (PET) biomarkers. Results Plasma p-tau has shown analytical validity (phase 2 primary aim 1) and first evidence of clinical validity (phase 3 primary aim 1), whereas the maturity level for Aβ remains to be partially achieved. Full and partial achievement has been assigned to p-tau and Aβ, respectively, in their associations to ante-mortem measures (phase 2 secondary aim 2). However, only preliminary evidence exists for the influence of covariates, assay comparison and cut-off criteria. Conclusions Despite the relative infancy of blood biomarkers, in comparison to CSF biomarkers, much has already been achieved for phases 1 through 3 – with p-tau having greater success in detecting AD and predicting disease progression. However, sufficient data about the effect of covariates on the biomarker measurement is lacking. No phase 4 (real-world performance) or phase 5 (assessment of impact/cost) aim has been tested, thus not achieved.

Helicobacter pylori infection and the risk of colorectal cancer: A meta-analysis of epidemiologic evidence.

2012 ◽  
Vol 30 (4_suppl) ◽  
pp. 408-408 ◽  
Author(s):  
Basile M. Njei ◽  
Ivo C. Ditah ◽  
Juliet Appiah ◽  
Raxitkumar Jinjuvadia ◽  
John W. Birk
Keyword(s):  
Colorectal Cancer ◽  
Helicobacter Pylori ◽  
Publication Bias ◽  
Study Design ◽  
Subgroup Analysis ◽  
Retrospective Studies ◽  
Meta Analysis ◽  
Helicobacter Pylori Infection ◽  
Quality Data ◽  
Current Evidence

408 Background: The association between Helicobacter pylori infection (HPI) and gastric cancer is well known, but it is unclear whether HPI is also a risk factor for colorectal cancer. Several epidemiological studies on the latter association have yielded conflicting results. The aim of this study is to summarize available evidence on the association between HPI and CRC, evaluating its magnitude and direction in a meta-analysis. Methods: Two reviewers independently conducted a systemic search on Medline, OvidSP and PubMed databases from January 1980 to July 2011 for studies on the association between HPI and CRC. The reference lists of eligible studies were next reviewed for additional studies on the subject. Firstly, a combined analysis including all studies was done. Next, subgroup analysis by study design and country of study (USA Vs Europe Vs Asia) were also performed. All analyses were done using the random effects model. Publication bias was assessed using the Begg’s and Egger’s tests and visual inspection of funnel plot. All analyses were performed using STATA 11. Results: Sixteen studies (14 retrospective and 2 prospective) including 12,892 participants were included in the analysis. Overall, HP was associated with a 49% significantly higher risk of CRC (OR 1.49, 95% CI: 1.22-1.82; P < 0.001). By study design, the association persisted only among the retrospective studies with a pooled OR of 1.43 (95% CI: 1.31-1.56, P = 0.004). The subgroup analysis by study region showed significant associations in Europe (OR 1.35, 95% CI 1.09-1.66) and Asia (RR 1.43, 95% CI 1.29-1.58). Though there was a 17% higher risk noted among studies done in the USA, this was not statistically significant. There was no evidence of publication bias in all the analyses. Conclusions: Current evidence on the association between H. pylori infection and CRC remains inconclusive. The absence of any association among the prospective studies (with less risk of bias) suggests that the association seen among the retrospective studies could be due to residual confounding. Better quality data is required before a conclusive statement on the association between HPI and CRC can be made.

Validity and Reliability Analysis of the PlotDigitizer Software Program for Data Extraction from Single-Case Graphs

2020 ◽  
Author(s):  
ORHAN AYDIN ◽  
Muhammet Yasin Yassikaya
Keyword(s):  
Single Case ◽  
Data Extraction ◽  
Meta Analysis ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Extraction Process ◽  
Data Series ◽  
Validity And Reliability ◽  
Raw Data ◽  
Software Program

Access to raw data of graphs presented in original articles to calculate effect size in meta-analysis studies of single-case research is one of the challenges that researchers encounter. Researchers typically use data extraction software programs to extract raw data from the graphs in articles. In this study, we aimed to analyze the validity and reliability of the use of PlotDigitizer software program, which is a widely used in literature and alternative to other data extraction programs, on computers with different operating systems. To accomplish this task, we performed the digitization of a total of 6.846 data points on three different computers using 15 hypothetical graphs with 20 data series and 186 graphs with 242 data series from 29 published articles. In addition, using the values we digitized we recalculated the 23 effect sizes presented in the original articles for validity analysis. Based on our sampling, we calculated inter-coder and intra-coder Pearson correlation coefficients. The results showed that PlotDigitizer could be an alternative to other programs as it is free and can run on many current and outdated systems, and it is valid and reliable as it is nearly perfect. Based on the obtained results and considering the data extraction process, various recommendations are presented for the researchers that will use PlotDigitizer program for the quantitative analysis of single-case graphs

scholarly journals Corporate Social Responsibility Disclosure and Performance: A Meta-Analytic Approach

2019 ◽  
Vol 11 (4) ◽  
pp. 1115 ◽  
Author(s):  
Dolores Gallardo-Vázquez ◽  
María Barroso-Méndez ◽  
María Pajuelo-Moreno ◽  
Julio Sánchez-Meca
Keyword(s):  
Corporate Social Responsibility ◽  
Social Responsibility ◽  
Meta Analysis ◽  
Pearson Correlation ◽  
Practical Importance ◽  
Correlation Coefficients ◽  
Moderating Variables ◽  
Corporate Social Responsibility Disclosure ◽  
And Performance ◽  
Corporate Social

Currently, a lack of consensus exists in the literature on the link between performance and corporate social responsibility disclosure (CSRD). A meta-analysis was carried out to shed light on this controversial topic, using the ABI/Inform Complete and EconLit databases as search tools. To isolate articles with substantive, methodological relevance, various filters were used. In addition to other criteria, all articles had to contain certain keywords related to the study’s variables and at least one of the seven keywords indicating empirical data analysis. As a result of this procedure, the meta-analysis included only 95 articles. To process the sample, we employed the procedure developed by Hunter and Schmidt. The results show that the CSRD-performance relationship is not significant enough for practical purposes. However, an analysis of moderating variables revealed that the connection becomes of practical importance when moderated by three key variables: region, type of disclosure, and measures of organization size. This research’s findings make a significant contribution by clarifying the links between CSRD and performance and identifying which variables can explain the diverse results of previous research. Regarding limitations, the meta-analysis was subject to the availability of published research and included only studies that reported Pearson correlation coefficients and standardized beta coefficients.

scholarly journals Spatial Extent of Amyloid-β Levels and Associations with Alzheimer’s Disease Biomarkers

2021 ◽  
Author(s):  
Hazal Ozlen ◽  
Alexa Pichet Binette ◽  
Theresa Köbe ◽  
Pierre-Francois Meyer ◽  
John Breitner ◽  
...  
Keyword(s):  
Older Adults ◽  
Cognitive Decline ◽  
Cognitive Performance ◽  
Gaussian Mixture Models ◽  
Amyloid Β ◽  
Gaussian Mixture ◽  
Brain Regions ◽  
Spatial Extent ◽  
Positron Emission ◽  
Tau Pet

Abstract Objective: To investigate the biological and clinical correlates of Aβ spatial extent deposition levels in cognitively unimpaired older adults.Methods: We included cognitively unimpaired older adults from three cohorts, totalling 529 participants (PREVENT-AD, n=129; ADNI, n=400 and HABS, n=288) who underwent Aβ positron emission tomography (PET). We used Gaussian-mixture models to identify region-specific thresholds of Aβ positivity in seven brain regions prone to early Aβ accumulation. Individuals were classified as having “widespread” Aβ deposition if they were positive in all seven regions, “regional” Aβ deposition if they were positive in one to six regions, or Aβ negative if negative in all regions. We compared demographics, genetics, tau-PET binding, and cognitive performance and decline between the three groups.Results: In all cohorts, most participants with regional Aβ-PET binding did not meet the cohort-specific criteria for Aβ-positivity (79% for PREVENT-AD, 57% for ADNI, and 100% for HABS). Regional Aβ groups had normal baseline cognition and relatively normal tau-PET binding, but a greater proportion of APOE ε4 carriers, decreased CSF Aβ1-42 levels, and greater amount of longitudinal Aβ-PET binding accumulation (only available in ADNI and HABS) when compared with the Negative Aβ groups. Widespread Aβ groups had lower baseline cognitive performance (PREVENT-AD only), faster cognitive decline (all cohorts) and greater amount of longitudinal tau binding than the other groups (only available in ADNI and HABS). Conclusions: Individuals with regional Aβ deposition might be the best candidate for preventive trials since they do not yet have widespread tau and cognitive decline. Widespread levels of Aβ seem to be needed for tau spreading.

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