2,413 research outputs found

    Intra-individual variability in information processing speed reflects white matter microstructure in multiple sclerosis

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    AbstractSlowed information processing speed is commonly reported in persons with multiple sclerosis (MS), and is typically investigated using clinical neuropsychological tests, which provide sensitive indices of mean-level information processing speed. However, recent studies have demonstrated that within-person variability or intra-individual variability (IIV) in information processing speed may be a more sensitive indicator of neurologic status than mean-level performance on clinical tests. We evaluated the neural basis of increased IIV in mildly affected relapsingā€“remitting MS patients by characterizing the relation between IIV (controlling for mean-level performance) and white matter integrity using diffusion tensor imaging (DTI). Twenty women with relapsingā€“remitting MS and 20 matched control participants completed the Computerized Test of Information Processing (CTIP), from which both mean response time and IIV were calculated. Other clinical measures of information processing speed were also collected. Relations between IIV on the CTIP and DTI metrics of white matter microstructure were evaluated using tract-based spatial statistics. We observed slower and more variable responses on the CTIP in MS patients relative to controls. Significant relations between white matter microstructure and IIV were observed for MS patients. Increased IIV was associated with reduced integrity in more white matter tracts than was slowed information processing speed as measured by either mean CTIP response time or other neuropsychological test scores. Thus, despite the common use of mean-level performance as an index of cognitive dysfunction in MS, IIV may be more sensitive to the overall burden of white matter disease at the microstructural level. Furthermore, our study highlights the potential value of considering within-person fluctuations, in addition to mean-level performance, for uncovering brainā€“behavior relationships in neurologic disorders with widespread white matter pathology

    Cost-Effectiveness of Disease-Modifying Therapies in the Management of Multiple Sclerosis for the Medicare Population

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    AbstractObjectiveTo evaluate the cost-effectiveness of disease-modifying therapies (DMTs) for the management of multiple sclerosis (MS) compared to best supportive care in the United States.MethodsCost-effectiveness analysis was undertaken using a state transition model of disease natural history and the impact of DMTs for the representative Medicare beneficiary with MS. Costs and outcomes were evaluated from the health-care payer perspective using a 50-year time horizon. Natural history data were drawn from a longitudinal cohort study. The effectiveness of the DMTs was evaluated through a systematic review. Utility data were taken from a study of patients with clinically definite MS in Nova Scotia. Resource use and cost data were derived from the Sonya Slifka database and associated literature.ResultsWhen based on placebo-controlled evidence, the marginal cost-effectiveness of interferon beta (IFNĪ²) and glatiramer acetate compared to best supportive care is expected to be in excess of $100,000 per quality-adjusted life-year gained. When evidence from head-to-head trials is incorporated into the model, the cost-effectiveness of 6 MIU IFNĪ²-1a is expected to be considerably less favorable. Treatment discontinuation upon progression to Expanded Disability Status Scale 7.0 is expected to improve the cost-effectiveness of all DMTs.ConclusionsFurther research is required to examine the long-term clinical effectiveness and cost-effectiveness of these therapies. There is no definitive guidance in the United States concerning discontinuation of DMTs; this study suggests that the prudent use of a treatment discontinuation rule may considerably improve the cost-effectiveness of DMTs

    The Kondo Dynamics of YbIn(1-x)AgxCu4

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    We present an infrared/optical study of the dynamics of the strongly correlated electron system YbIn(1-x)AgxCu4 as a function of doping and temperature for x ranging from 0 to 1, and T between 20 and 300 K. This study reveals information about the unusual phase transition as well as the phases themselves. Scaling relations emerge from the data and are investigated in detail using a periodic Anderson model based calculation. We also provide a picture in which to view both the low and high-energy x-dependent features of the infrared data, including identification of high energy, temperature dependent features.Comment: 12 pages, 11 figures, submitted Phys. Rev.

    A BODIPY-Cyclooctyne for Protein Imaging in Live Cells

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    Cellular proteins that bear reactive azides can be imaged by fluorescence microscopy following strain-promoted ligation to cyclooctyne dyes. Here we describe BODIPY-cyclooctyne (BDPY), a membrane-permeant fluorophore that can be used to label intracellular proteins in live mammalian cells. Flow cytometry reveals fluorescence signals more than 25-fold above background after labeling of azide-tagged cells with BDPY

    Disease-Modifying Drugs for Multiple Sclerosis and Association With Survival

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    BACKGROUND AND OBJECTIVES: We examined the association between the disease-modifying drugs (DMDs) for multiple sclerosis (MS) and survival in a multiregion population-based study. METHODS: We accessed multiple administrative health databases from 4 Canadian provinces. Persons with MS were identified and followed from the most recent of the first MS or demyelinating event or January 1, 1996 (index date), until death, emigration, or December 31, 2017. Association between the first-generation and second-generation DMDs and all-cause mortality was examined using stratified Cox proportional hazard models, reported as adjusted hazard ratios (aHRs). Timing of DMD initiation was explored, with findings reported at 2, 5, or 10 years postindex date, representing very early, early, or late initiation. RESULTS: We identified 35,894 persons with MS; 72% were female. The mean age at index date was 44.5 years (SD = 13.6). The total person-years of follow-up while DMD-exposed was 89,180, and total person-years while unexposed was 342,217. Compared with no exposure, exposure to any DMD or to any first-generation DMD was associated with a 26% lower hazard of mortality (both aHRs 0.74; 95% CI 0.56-0.98), while any second-generation DMD exposure was associated with a 33% lower hazard (aHR 0.67; 95% CI 0.46-0.98). Earlier DMD initiation (beta-interferon or glatiramer acetate vs no exposure) was associated with a significant mortality effect (p < 0.05), while later initiation was not (95% CIs included 1). However, the survival advantage with earlier initiation diminished over time, no longer reaching statistical significance at 15 years postindex date. DISCUSSION: Our study demonstrates an association between the DMDs for MS and improved survival in the real-world setting

    Prospective memory functioning among ecstasy/polydrug users: evidence from the Cambridge Prospective Memory Test (CAMPROMPT)

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    Rationale: Prospective memory (PM) deficits in recreational drug users have been documented in recent years. However, the assessment of PM has largely been restricted to self-reported measures that fail to capture the distinction between event-based and time-based PM. The aim of the present study is to address this limitation. Objectives: Extending our previous research, we augmented the range laboratory measures of PM by employing the CAMPROMPT test battery to investigate the impact of illicit drug use on prospective remembering in a sample of cannabis only, ecstasy/polydrug and non-users of illicit drugs, separating event and time-based PM performance. We also administered measures of executive function and retrospective memory in order to establish whether ecstasy/polydrug deficits in PM were mediated by group differences in these processes. Results: Ecstasy/polydrug users performed significantly worse on both event and time-based prospective memory tasks in comparison to both cannabis only and non-user groups. Furthermore, it was found that across the whole sample, better retrospective memory and executive functioning was associated with superior PM performance. Nevertheless, this association did not mediate the drug-related effects that were observed. Consistent with our previous study, recreational use of cocaine was linked to PM deficits. Conclusions: PM deficits have again been found among ecstasy/polydrug users, which appear to be unrelated to group differences in executive function and retrospective memory. However, the possibility that these are attributable to cocaine use cannot be excluded
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