1,720,965 research outputs found
Peripheral Nervous System Involvement in Amyotrophic Lateral Sclerosis: from diagnosis to disease understanding and development of novel biomarkers
Full text linkThe mainstay of Amyotrophic lateral sclerosis (ALS) diagnosis is the clinical evaluation, and it can be challenging when its first manifestations overlap with those of ALS mimic disorders (ALSmd). The lack of specific diagnostic test prevents an early diagnosis. The definition of prognosis in ALS is hampered by the heterogeneity of its clinical features, with variability in survival being the most salient feature. Therefore, wet biomarkers are needed to aid clinical decision, track disease progression, and better define disease trajectories. Recent advances highlighted neurofilaments as the most promising biomarkers for ALS. In the first part of our results, we assessed serum phosphorylated neurofilament heavy chain (pNfH) in a large ALS cohort (n=219). pNfH was an independent predictor of survival for ALS and its concentration was heterogenous across the ALS phenotypes, patients with fast disease progression and a predominant upper motor neuron burden showed the highest serum concentration. Subsequently, we performed gene expression and pathways analyses, on 8 motor nerve biopsies of patients with ALS and compared with 7 motor neuropathies as controls, identifying Ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1) as a potential candidate biomarker for ALS. Therefore, we tested UCHL1 in an independent large ALS and control cohorts to assess its diagnostic and prognostic performances. At the same time, we also tested serum Neurofilament light chain (NfL) and Glial fibrillary acidic protein (GFAP). In our analysis, UCHL1 resulted not promising as diagnostic biomarkers, conversely, it was an independent prognostic factor, proving itself helpful in the stratification of survival for patients with lower NfL levels. NfL consistently reached the best diagnostic performance for ALS showing almost optimal performance in discriminating ALS from healthy controls and other neurodegenerative diseases. Conversely, the diagnostic yield in distinguishing ALS from ALSmd was lower with specificity decreasing to 78.0%. As similarly observed for the pNfH, NfL concentrations were heterogenous across the ALS phenotypes and higher concentrations were detected in patients with a fast disease progression and a predominant upper motor neuron burden. Serum GFAP, a known marker of astrogliosis, differs among cognitive phenotypes, namely ALS with concomitant cognitive impairment or FTD had higher levels compared with ALS with normal cognition. Therefore, GFAP might be instrumental in tracking the occurrence of cognitive decline in ALS.La diagnosi della Sclerosi Laterale Amiotrofica (SLA) è principalmente basata sulla valutazione clinica e può essere talvolta problematica soprattutto quando le manifestazioni cliniche sono sovrapponibili a quelle di malattie neurologiche che possono mimare la SLA. L’assenza di test diagnostici specifici limitano la possibilità di formulare la diagnosi in fase precoce di malattia. La definizione della prognosi dei malati di SLA è limitata dall’eterogeneità fenotipica della malattia e dalla sua intrinseca variabilità inter-individuale. Alla luce di tali considerazioni, eventuali biomarcatori potrebbero essere utili nel guidare decisioni diagnostiche, terapeutiche e di valutazione prognostica. Recenti evidenze di letteratura hanno individuato i neurofilamenti a catena leggera e pesante (NfL e pNfH) come i due più promettenti biomarcatori per la SLA.
Nella prima parte del nostro studio, abbiamo valutato la concentrazione sierica dei pNfH in una numerosa cohorte di pazienti affetti da SLA (n=219). I nostri risultati evidenziano che in analisi multivariata i pNfH sono risultati fattori indipendenti nel predizione della sopravvivenza dei pazienti. Inoltre, la concentrazione dei pNfH è risultata eterogenea nella popolazione SLA; i valori più elevati sono stati riscontrati nei pazienti con prevalente interessamento del I neurone di moto e concomitante elevata velocità di progressione di malattia. In seguito, abbiamo effettuato un’analisi di espressione genica e sequenziale analisi di pathways su 8 nervi motori ottenuti da pazienti SLA e 7 da pazienti con neuropatia motoria considerati come controlli. Da tale analisi abbiamo indentificato UCHL1 come una proteina potenzialmente promettente come biomarcatore per la SLA. Abbiamo analizzato i valori plasmatici di tale proteina esplorandone le potenzialità diagnostiche e prognostiche, in parallelo abbiamo misurato anche i valori plasmatici di NfL, GFAP e tTAU in coorte di pazienti SLA (n=143) e di controllo. Nel nostro studio UCHL1 non si è confermato un promettente biomarcatore per la diagnosti di SLA, tuttavia è risultato essere un fattore determinante per la definizione prognostica dei pazienti stratificando ulteriormente la prognosi dei pazienti SLA con bassi valori plasmatici di NfL. Dalle nostre analisi si conferma che NfL come i migliori biomarcatori diagnostici sia per discriminare i pazienti SLA dai controlli sani (HC) e da pazienti affetti da altre malattie neurodegenerative (DEG). Tuttavia, la performance diagnostica degli NfL nel distinguere le SLA dalle patologie SLA mimic è sensibilmente ridotta con una sensibilità del 78%. Come osservato per i pNfH, anche i livelli di NfL sono più elevati in pazienti con prevalente interessamento del I neurone di moto e concomitante elevata velocità di progressione di malattia. I livelli plasmatici di GFAP riflettono i diversi gradi di interessamento cognitivo nei pazienti affetti da SLA, infatti pazienti SLA con concomitante demenza fronto-temporale o interessamento cognitivo presentavano più elevati valori di GFAP rispetto a pazienti SLA con selettivo interessamento motorio. Alla luce di questi dati GFAP potrebbe essere un biomarcatore utile per tracciare il declino cognitivo dei pazienti con SLA
Neurofilament light chain as a biological marker for amyotrophic lateral sclerosis: a meta-analysis study
No full textAim: The aim of the present metanalysis is to evaluate blood and CSF Neurofilament light chain (NfL) concentrations in ALS patients, compared to healthy controls, ALS mimic disorders (ALSmd) and other neurological diseases (OND), and to evaluate their diagnostic yield against ALSmd. Methods: Search engines were systematically investigated for relevant studies. A random effect model was applied to estimate the pooled standard mean difference in NfL levels between ALS and controls and a bivariate mixed-effects model was applied to estimate their diagnostic accuracy on blood and CSF. Results and conclusions: NfL CSF levels were higher in ALS compared with all other control groups. On blood, NfL levels were significantly higher in ALS patients compared with healthy controls and ALSmd. In a subgroup analysis, the use of SIMOA yielded to a better differentiation between ALS and controls on blood, compared with ELISA. Studies performed on CSF (AUC = 0.90) yielded to better diagnostic performances compared with those conducted on blood (AUC = 0.78). Further prospective investigations are needed to determine a diagnostic cutoff, exploitable in clinical practice
Unveiling the SOD1-mediated ALS phenotype: insights from a comprehensive meta-analysis
No full textBackground and objectives Amyotrophic lateral sclerosis associated with mutations in SOD1 (SOD1-ALS) might be susceptible to specific treatment. The aim of the study is to outline the clinical features of SOD1-ALS patients by comparing them to patients without ALS major gene variants and patients with variants in other major ALS genes. Defining SOD1-ALS phenotype may assist clinicians in identifying patients who should be prioritized for genetic testing.Methods We performed an extensive literature research including original studies which reported the clinical features of SOD1-ALS and at least one of the following patient groups: C9ORF72 hexanucleotide repeat expansion (C9-ALS), TARDBP (TARDBP-ALS), FUS (FUS-ALS) or patients without a positive test for a major-ALS gene (N-ALS). A random effects meta-analytic model was applied to clinical data extracted encompassing sex, site and age of onset. To reconstruct individual patient survival data, the published Kaplan-Meier curves were digitized. Data were measured as odds ratio (OR) or standardized mean difference (SMD) as appropriate. Median survival was compared between groups.Results Twenty studies met the inclusion criteria. We identified 721 SOD1-ALS, 470 C9-ALS, 183 TARDBP-ALS, 113 FUS-ALS and 2824 N-ALS. SOD1-ALS showed a higher rate of spinal onset compared with N-ALS and C9-ALS (OR = 4.85, 95% CI = 3.04-7.76; OR = 10.47, 95% CI = 4.32-27.87) and an earlier onset compared with N-ALS (SMD = - 0.45, 95% CI = - 0.72 to - 0.18). SOD1-ALS had a similar survival compared with N-ALS (p = 0.14), a longer survival compared with C9-ALS (p < 0.01) and FUS-ALS (p = 0.019) and a shorter survival compared with TARDBP-ALS (p < 0.01).Discussion This study indicates the presence of a specific SOD1-ALS phenotype. Insights in SOD1-ALS clinical features are important in genetic counseling, disease prognosis and support patients' stratification in clinical trials
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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