1,721,167 research outputs found
The contribution of epidemiology to defining the most appropriate approach to genetic research on schizophrenia
No full textPsychosis is thought to have a strong genetic component, but many efforts to discover the underlying putative schizophrenia genes have yielded disappointing results. In fact, no strong associations emerged in the first genome-wide association studies in psychiatry and weakly observed associations were not related to the candidate genes identified in previous studies. These partially successful findings may be explained by the fact that genetic research in psychiatry suffers from confounding issues related to phenotype definition, the considerable degree of phenotypic variability and diagnostic uncertainty, absence of specific neuropathological features and environmental influences. To make progress it is first necessary to deconstruct psychosis based on symptomatology, and then to correlate particular phenotypes with genetic variants. Moreover, it is time to conduct studies that define persistent aspects of the schizophrenic profile that are more likely to represent an underlying biological pathogenesis, as opposed to fluctuating symptoms that are possibly environmentally mediated. In fact, progress in understanding the etiology of schizophrenia will depend upon the availability of good measures of genetic liability as well as relevant environmental exposures during critical periods of an individual's life. If environmental and/or genetic factors are not precisely measured, it is impossible to study their independent effects or interactions
The biological correlates of childhood trauma in first episode psychosis
Get PDFObjective To overview biological mechanisms connecting childhood trauma to the development of psychosis. Methods We reviewed the evidence regarding biological correlates associated with childhood trauma in individuals affected by first episode psychosis (FEP) in terms of: 1) Hypothalamic-pituitary- adrenal (HPA) axis & cytokines levels; 2) gene × environment interaction, epigenetic and gene expression modifications and 3) metabolic biomarkers. Results Childhood trauma and early psychosis even when explored separately were found associated with several biological correlates. Regarding the immune system activity, in terms of both HPA axis functioning and cytokines levels, FEP patients exposed to childhood trauma showed 1) a less reactive HPA axis, characterized by a blunted cortisol awakening response, and higher serum levels of Tumor necrosis Factor-α (TNF-α) and C-reactive protein (CRP) in comparison with patients without childhood trauma. Genetics and epigenetics were also proven significantly different in traumatized FEP in comparison with non-exposed individuals. Specifically, first 2) the Val/Val genotype at the Val158Met polymorphism in the COMT gene, the A allele at rs4713916 and rs9296158 single nucleotide polymorphisms (SNPs) and the TT homozygosis at rs1360780 SNP in the FKBP5 gene were demonstrated to be risk factors for psychosis in traumatized individuals. Second, childhood trauma in FEP was proven significantly associated with global DNA hypo-methylation and lower BDNF gene expression. Finally, regarding metabolic changes associated with childhood trauma in FEP 3) higher levels of glycated hemoglobin and higher c-peptide and insulin levels were proven in patients exposed to childhood trauma in comparison with those without childhood trauma. Conclusions This review has given evidence regarding associations between childhood trauma and its biological correlates in first episode psychosis. Nonetheless, future studies are warranted to investigate putative biological mediators and their temporal sequence in order to elucidate developmental trajectories
La diagnosi: dagli strumenti della ricerca al mondo reale
No full textnel capitolo viene descritto il concetto di diagnosi in psichiatria e il suo utilizzo nella pratica clinica e di ricerca
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Targeting of calsequestrin to the sarcoplasmic reticulum following deletions of its acidic carboxy terminus
No full textCalsequestrin (CS) is the Ca21 binding protein of the junctional sarcoplasmic reticulum (jSR) lumen. Recently, a chimeric CS-HA1, obtained by adding the nineamino-
acid viral epitope hemagglutinin (HA1) to the COOH terminus of CS, was shown to be correctly segregated to the sarcoplasmic reticulum [A. Nori, K. A. Nadalini, A. Martini,
R. Rizzuto, A. Villa, and P. Volpe. Am. J. Physiol. 272 (Cell
Physiol. 41): C1420–C1428, 1997].A putative targeting mechanism of CS to jSR implies electrostatic interactions between negative charges on CS and positive charges on intraluminal domains of jSR integral proteins, such as triadin and junctin. To test this hypothesis, 2 deletion mutants of chimeric CS were engineered: CS-HA1DGlu-Asp, in which the 14 acidic residues [-Glu-(Asp)5-Glu-(Asp)7-] of the COOH-terminal tail were removed, and CS-HA1D49COOH, in which the last, mostly acidic, 49 residues of the COOH terminus were removed. Both mutant cDNAs were transiently transfected in HeLa cells, myoblasts of rat skeletal muscle primary cultures, or regenerating soleus muscle fibers of adult rats. The expression and intracellular localization of CS-HA1 mutants were studied by epifluorescence microscopy with use of antibodies against CS or HA1. CS-HA1 mutants were shown to be expressed, sorted, and correctly segregated to jSR. Thus short or long deletions of the COOH-terminal acidic tail do not influence the targeting mechanism of CS
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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