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  • 1
    In: JAIDS Journal of Acquired Immune Deficiency Syndromes, Ovid Technologies (Wolters Kluwer Health), Vol. 84, No. 4 ( 2020-08-1), p. 414-421
    Abstract: Frailty is an important clinical concern for the aging population of people living with HIV (PLWH). The objective of this study was to identify the combination of risk features that distinguish frail from nonfrail individuals. Setting: Machine learning analysis of highly dimensional risk features was performed on a clinical cohort of PLWH. Methods: Participants included 105 older (average age = 55.6) PLWH, with at least a 3-month history of combination antiretroviral therapy (median CD4 = 546). Predictors included demographics, HIV clinical markers, comorbid health conditions, cognition, and neuroimaging (ie, volumetrics, resting-state functional connectivity, and cerebral blood flow). Gradient-boosted multivariate regressions were implemented to establish linear and interactive classification models. Model performance was determined by sensitivity/specificity (F1 score) with 5-fold cross validation. Results: The linear gradient-boosted multivariate regression classifier included lower current CD4 count, lower psychomotor performance, and multiple neuroimaging indices (volumes, network connectivity, and blood flow) in visual and motor brain systems (F1 score = 71%; precision = 84%; and sensitivity = 66%). The interactive model identified novel synergies between neuroimaging features, female sex, symptoms of depression, and current CD4 count. Conclusions: Data-driven algorithms built from highly dimensional clinical and brain imaging features implicate disruption to the visuomotor system in older PLWH designated as frail individuals. Interactions between lower CD4 count, female sex, depressive symptoms, and neuroimaging features suggest potentiation of risk mechanisms. Longitudinal data-driven studies are needed to guide clinical strategies capable of preventing the development of frailty as PLWH reach advanced age.
    Type of Medium: Online Resource
    ISSN: 1525-4135
    RVK:
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2020
    detail.hit.zdb_id: 2038673-4
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  • 2
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S1 ( 2022-12)
    Abstract: Given the triplication of chromosome 21 and the location of the amyloid precursor protein gene on chromosome 21, almost all adults with Down syndrome (DS) develop Alzheimer disease (AD)‐like pathology and dementia during their lifetime. Comparing amyloid accumulation in DS to autosomal dominant AD (ADAD), another genetic form of AD, may improve our understanding of early AD pathology development. Method We assessed amyloid positron emission tomography (PET) imaging in 192 participants with DS and 33 sibling controls from the Alzheimer’s Biomarker Consortium‐Down Syndrome (ABC‐DS) and 265 mutation‐carriers (MC) and 169 familial controls from the Dominantly Inherited Alzheimer Network (DIAN) ( Table 1 ). We calculated regional standard uptake value ratios (SUVR) using a cerebellar cortex reference region and converted global amyloid burden SUVR to centiloids. We compared amyloid PET by cognitive status and estimated‐years‐to‐symptom‐onset (EYO). EYO was calculated for DIAN participants by subtracting their age from parental age of symptom onset and for ABC‐DS participants by subtracting their age from 50.2 years, a published average age of symptom onset in a large sample of individuals with DS (Fortea et al., 2020). In a subset of participants, we assessed the relationship between amyloid PET and CSF Aβ42/40. Result The relationship between CSF Aβ42/40 and amyloid PET was similar in DS and MC participants ( Figure 1 ). We did not observe significant differences between MC and DS grouped by cognitive status ( Figure 2 ). However, when assessed over EYO, global amyloid burden was significantly elevated in MC at EYO ≥ ‐23 but was not elevated in DS until EYO ≥ ‐15 ( Figure 3 ). We observed early cortical and subcortical amyloid PET increases in both groups, but we also measured some regional differences in amyloid PET changes between MC and DS, specifically in the medial occipital region ( Figure 4 and 5 ). Conclusion These results demonstrate similarities in the relationship between amyloid biomarkers and the levels of amyloid accumulation in ADAD and DS. However, we also observed a 5‐10 year delay and some regional differences in amyloid accumulation in DS. This is important for future clinical trials to consider when recruiting participants and determining treatment efficacy.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
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  • 3
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S6 ( 2022-12)
    Abstract: Given the triplication of chromosome 21 and the location of the amyloid precursor protein gene on chromosome 21, almost all adults with Down syndrome (DS) develop Alzheimer disease (AD)‐like pathology and dementia during their lifetime. Comparing amyloid accumulation in DS to autosomal dominant AD (ADAD), another genetic form of AD, may improve our understanding of early AD pathology development. Method We assessed amyloid positron emission tomography (PET) imaging in 192 participants with DS and 33 sibling controls from the Alzheimer’s Biomarker Consortium‐Down Syndrome (ABC‐DS) and 265 mutation‐carriers (MC) and 169 familial controls from the Dominantly Inherited Alzheimer Network (DIAN) ( Table 1 ). We calculated regional standard uptake value ratios (SUVR) using a cerebellar cortex reference region and converted global amyloid burden SUVR to centiloids. We compared amyloid PET by cognitive status and estimated‐years‐to‐symptom‐onset (EYO). EYO was calculated for DIAN participants by subtracting their age from parental age of symptom onset and for ABC‐DS participants by subtracting their age from 50.2 years, a published average age of symptom onset in a large sample of individuals with DS (Fortea et al., 2020). In a subset of participants, we assessed the relationship between amyloid PET and CSF Aβ42/40. Result The relationship between CSF Aβ42/40 and amyloid PET was similar in DS and MC participants ( Figure 1 ). We did not observe significant differences between MC and DS grouped by cognitive status ( Figure 2 ). However, when assessed over EYO, global amyloid burden was significantly elevated in MC at EYO ≥ ‐23 but was not elevated in DS until EYO ≥ ‐15 ( Figure 3 ). We observed early cortical and subcortical amyloid PET increases in both groups, but we also measured some regional differences in amyloid PET changes between MC and DS, specifically in the medial occipital region ( Figure 4 and 5 ). Conclusion These results demonstrate similarities in the relationship between amyloid biomarkers and the levels of amyloid accumulation in ADAD and DS. However, we also observed a 5‐10 year delay and some regional differences in amyloid accumulation in DS. This is important for future clinical trials to consider when recruiting participants and determining treatment efficacy.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
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  • 4
    In: Brain, Oxford University Press (OUP), Vol. 146, No. 7 ( 2023-07-03), p. 2944-2956
    Abstract: Heterogeneity in progression to Alzheimer's disease (AD) poses challenges for both clinical prognosis and clinical trial implementation. Multiple AD-related subtypes have previously been identified, suggesting differences in receptivity to drug interventions. We identified early differences in preclinical AD biomarkers, assessed patterns for developing preclinical AD across the amyloid-tau-(neurodegeneration) [AT(N)] framework, and considered potential sources of difference by analysing the CSF proteome. Participants (n = 10) enrolled in longitudinal studies at the Knight Alzheimer Disease Research Center completed four or more lumbar punctures. These individuals were cognitively normal at baseline. Cerebrospinal fluid measures of amyloid-β (Aβ)42, phosphorylated tau (pTau181), and neurofilament light chain (NfL) as well as proteomics values were evaluated. Imaging biomarkers, including PET amyloid and tau, and structural MRI, were repeatedly obtained when available. Individuals were staged according to the amyloid-tau-(neurodegeneration) framework. Growth mixture modelling, an unsupervised clustering technique, identified three patterns of biomarker progression as measured by CSF pTau181 and Aβ42. Two groups (AD Biomarker Positive and Intermediate AD Biomarker) showed distinct progression from normal biomarker status to having biomarkers consistent with preclinical AD. A third group (AD Biomarker Negative) did not develop abnormal AD biomarkers over time. Participants grouped by CSF trajectories were re-classified using only proteomic profiles (AUCAD Biomarker Positive versus AD Biomarker Negative = 0.857, AUCAD Biomarker Positive versus Intermediate AD Biomarkers = 0.525, AUCIntermediate AD Biomarkers versus AD Biomarker Negative = 0.952). We highlight heterogeneity in the development of AD biomarkers in cognitively normal individuals. We identified some individuals who became amyloid positive before the age of 50 years. A second group, Intermediate AD Biomarkers, developed elevated CSF ptau181 significantly before becoming amyloid positive. A third group were AD Biomarker Negative over repeated testing. Our results could influence the selection of participants for specific treatments (e.g. amyloid-reducing versus other agents) in clinical trials. CSF proteome analysis highlighted additional non-AT(N) biomarkers for potential therapies, including blood–brain barrier-, vascular-, immune-, and neuroinflammatory-related targets.
    Type of Medium: Online Resource
    ISSN: 0006-8950 , 1460-2156
    RVK:
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2023
    detail.hit.zdb_id: 1474117-9
    SSG: 12
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  • 5
    Online Resource
    Online Resource
    Wiley ; 2018
    In:  Biochemistry and Molecular Biology Education Vol. 46, No. 6 ( 2018-11), p. 602-611
    In: Biochemistry and Molecular Biology Education, Wiley, Vol. 46, No. 6 ( 2018-11), p. 602-611
    Abstract: Conceptual understanding and reasoning of nonscience major students enrolled in a course on biotechnology were evaluated before and after instruction. The instrument for analysis of student understanding was the Biotechnology Instrument for Knowledge Elicitation (BIKE). The BIKE targets 11 key concepts, as determined by experts in the field. A statistically significant score improvement was observed in each of the 11 concept areas after completion of the course, Biotechnology in Society ( N = 117). Student responses to both the pretest and posttest were highly informative and revealed several common misconceptions that could have been overlooked in a closed form testing scenario. These alternative conceptions and recommended clarifications have been presented here. Our goal in documenting and distributing these is to better equip educators in biology and biochemistry to anticipate student preconceptions, design targeted interventions, and improve student conceptual reasoning in topics pertaining to biology and biotechnology. © 2018 International Union of Biochemistry and Molecular Biology, 46(6):602–611, 2018.
    Type of Medium: Online Resource
    ISSN: 1470-8175 , 1539-3429
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 2039717-3
    SSG: 12
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  • 6
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S5 ( 2022-12)
    Abstract: Tau PET imaging is an established tool for studying Alzheimer Disease but its sensitivity to primary age‐related tauopathy (PART) as well as sex effects in individuals without abnormal levels of amyloid are unknown. Methods Cross‐sectional data were collected from 2014 to 2019 in 144 cognitively normal younger, middle‐aged, and older adults free from amyloid pathology as quantified using PET. Regional values of tau PET binding were measured using flortaucipir. Statistical models examined the main effects of increasing age, sex, race, and sub‐threshold levels of amyloid. Secondary analyses also examined the relationship between tau PET binding and iron as measured using T2 * weighted imaging and calcification as measured using CT. Results There were significant positive associations between tau binding and age in 19 regions, with the largest effects seen in the inferior temporal cortex (t=4.59), caudate (t=9.58), and putamen (t=12.57). Iron as measured using T2 * imaging mediated only a modest (11.9%) amount of the association between age and tau binding. Elevated tracer uptake in females was present in 23 regions in frontal, lateral parietal, and temporal regions including, most prominently the rostral middle frontal gyrus (t=7.48), superior temporal gyrus (t=5.12) and the inferior temporal gyrus (t=4.22). There were no significant effects of race or sub‐threshold levels of amyloid. Conclusions Tau PET is sensitive to primary effects of age in regions consistent with the neuropathological definition of PART although strong age effects in regions of off‐target binding were also present. There was a robust effect of sex, suggesting prior observations of elevated binding in women is not solely a potentiation of Alzheimer pathology but instead represents an ubiquitous phenomenon. Understand how both sex and age impact tracer binding is critical to understanding the utility of PET tracers as well as interpreting tracer values in the context of disease.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
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  • 7
    In: Scientific Reports, Springer Science and Business Media LLC, Vol. 12, No. 1 ( 2022-04-20)
    Abstract: Our objective was to identify functional brain changes that associate with driving behaviors in older adults. Within a cohort of 64 cognitively normal adults (age 60+), we compared naturalistic driving behavior with resting state functional connectivity using machine learning. Functional networks associated with the ability to interpret and respond to external sensory stimuli and the ability to multi-task were associated with measures of route selection. Maintenance of these networks may be important for continued preservation of driving abilities.
    Type of Medium: Online Resource
    ISSN: 2045-2322
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2615211-3
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  • 8
    In: JAMA Oncology, American Medical Association (AMA), Vol. 8, No. 11 ( 2022-11-01), p. 1652-
    Abstract: Determining whether neurofilament light chain (NfL) elevations in patients who develop immune effector cell–associated neurotoxicity syndrome (ICANS) occur before or after infusion of cellular product is important to identify high-risk patients and inform whether neuroaxonal injury is latent or a consequence of treatment. Objective To quantify serial NfL levels in patients undergoing cellular therapy. Design, Setting, and Participants This retrospective 2-center study examined plasma NfL levels in 30 patients with detailed medical and treatment history, including all major pretreatment and posttreatment risk factors. Exclusion criteria included dementia and severe, symptomatic central nervous system (CNS) involvement. Main Outcomes and Measures Patients’ NfL levels were measured at 7 time points: baseline (prelymphodepletion), during lymphodepletion, postinfusion day (D) 1, D3, D7, D14, and D30. Prediction accuracy for the development of ICANS was next modeled using receiver operating characteristic (ROC) classification. Finally, univariate and multivariate modeling examined the association between NfL levels, ICANS, and potential risk factors including demographic (age, sex), oncologic (tumor burden, history of CNS involvement), neurologic (history of nononcologic CNS disease or neuropathy), and neurotoxic exposure histories (vincristine, cytarabine, methotrexate, or CNS radiotherapy). Results A total of 30 patients (median [range] age, 64 [22-80] years; 12 women [40%] and 18 men [60%] ) were included. Individuals who developed ICANS had elevations in NfL prior to lymphodepletion and chimeric antigen receptor T-cell infusion compared with those who did not develop ICANS (no ICANS: 29.4 pg/mL, vs any ICANS: 87.6 pg/mL; P   & amp;lt; .001). Baseline NfL levels further predicted ICANS development with high accuracy (area under the ROC curve, 0.96), sensitivity (0.91), and specificity (0.95). Levels of NfL remained elevated across all time points, up to 30 days postinfusion. Baseline NfL levels correlated with ICANS severity but not demographic factors, oncologic history, nononcologic neurologic history, or history of exposure to neurotoxic therapies. Conclusions and Relevance In a subset of patients in this cross-sectional study, the risk of developing ICANS was associated with preexisting neuroaxonal injury that was quantifiable with plasma NfL level. This latent neuroaxonal injury was present prior to drug administration but was not associated with historic neurotoxic therapies or nononcologic neurologic disease. Preinfusion NfL may further permit early screening and identification of patients most at risk for ICANS. Additional studies are needed to determine NfL’s utility as a predictive biomarker for early (preemptive or prophylactic) intervention and to delineate the origin of this underlying neural injury.
    Type of Medium: Online Resource
    ISSN: 2374-2437
    Language: English
    Publisher: American Medical Association (AMA)
    Publication Date: 2022
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  • 9
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S7 ( 2022-12)
    Abstract: The preclinical stage of Alzheimer disease (AD) is a clinically silent period that is detectable through neuroimaging and biofluid biomarkers of amyloid, tau, and neurodegeneration. We evaluated whether performance of cognitively‐focused complex daily activities is associated with plasma biomarkers of brain amyloidosis or neuroaxonal injury in cognitively normal (CN) older adults. Method In this cross‐sectional analysis of an ongoing longitudinal cohort study, CN older adults performed three cognitively‐focused complex daily activtites (shopping, checkbook balancing, and medication management) from the Performance Assessment of Self‐Care Skills (PASS) in their home. PASS tasks were scored for independence of performance, with more assistance required indicating worse performance. Participants also had a plasma sample obtained within two years of completing the PASS. Plasma amyloid (Aβ42 and Aβ40) were evaluated by high precision immunoprecipitation mass spectrometry assays and neurofilament light (NfL), a marker of neuroaxonal injury, was measured with single molecule array (Simoa) assays. Amyloid Probability Score (APS) was calculated from a combination of plasma Aβ42/Aβ40, APOE status, and age and reflects the likelihood that an individual will be amyloid positive on an amyloid positron emission tomography (PET) scan. Nonparametric partial correlations were used to examine the associations between PASS performance and biomarkers of AD (plasma Aβ42/Aβ40, APS, and plasma NfL), controlling for age and sex. Result 105 CN participants (mean age 74.7 years, 55% female, 88% white) were included. After controlling for age and sex, worse performance of complex daily tasks (more assistance required) was associated with increased plasma NfL (Spearman’s ρ: 0.234, p = 0.04) but not plasma Aβ42/Aβ40 or APS. Conclusion This study suggests that worse performance of complex daily activities in CN older adults may be associated with increased plasma NfL, a marker of neuroaxonal injury, but not with other plasma biomarkers of brain amyloidosis (plasma Aβ42/Aβ40 or APS). These findings could lead to a better understanding of functional changes that may associate with neuroaxonal injury prior to the onset of noticeable memory symptoms in AD or related dementias.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
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  • 10
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S6 ( 2022-12)
    Abstract: Alzheimer disease (AD) is a complex disorder characterized by changes in amyloid, tau, as well as neurodegeneration. Neuroimaging and cerebrospinal fluid (CSF) assays provide complimentary measures of these pathologies although the Correspondence between such biomarkers is not well elucidated. Methods Data from 313 cognitively unimpaired and 59 impaired individuals aged 45 to 91 was drawn from the Charles F. and Joanne Knight Alzheimer Disease Research Center. Participants had neuroimaging, CSF, and clinical data acquired within one year. Neuroimaging variables included summary measures of amyloid (Centiloids from either PiB or Florebetapir), tau (Flortaucipir), and atrophy (MRI cortical signature). CSF variables were the Aβ 42/40 ratio, ptau 181 , and neurofilament light chain (NfL). Biomarker cutoffs were determined using Gaussian‐Mixture modeling as well as a Youden Index to maximally separate cognitively unimpaired individuals from those with a clinical AD diagnosis. Rank order congruence between biomarkers was determined using Kendall correlations (t). Results Gaussian Mixture Modeling (dashed lines) and Youden Index (solid lines) approaches produced disparate cutoffs, particularly for neurodegenerative markers (NfL/atrophy) indicating the challenges inherent to binarizing continuous variables (Figure 1). Kendall’s t provide an estimate of pairwise congruence between biomarkers in cognitively unimpaired (CN, CDR=0, upper left diagonal) and impaired individuals (CI, CDR 〉 0, lower right diagonal) (Figure 2). Measures of amyloid had generally high concordance (t ‐0.45 and ‐0.43 for CN and CI respectively ) than those of non‐specific neurodegeneration, which were quite low (t ‐0.16 and ‐0.23). Although ptau 181 and tau were moderately related (t 0.21 and 0.23), ptau 181 had higher Correspondence with both PET and CSF measures of amyloid. A sequential timing of biomarkers could be clearly seen when plotting z‐scored biomarkers as a function of amyloid PET (Figure 3). Conclusions Neuroimaging and CSF markers provide complimentary information and help to deeply phenotype the AD biological cascade. While measures of amyloid are highly congruent, non‐specific markers of neurodegeneration have poor agreement., CSF measures of phosphorylated tau likely index a response to amyloidosis rather than being a marker of tau aggregation.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
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