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Onder sociale wetenschappen. Toegelicht aan psychologie, economie en taalkunde
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COMBINAZIONE DI EPZ-5676 E SORAFENIB COME NUOVA STRATEGIA TERAPEUTICA PER IL TRATTAMENTO DELLE LEUCEMIE ACUTE MIELOIDI PEDIATRICHE
No full textLe traslocazioni di MLL, presenti in oltre il 20%
delle AML pediatriche, si associano a prognosi sfavorevole.
Pertanto, continui sforzi sono necessari per identificare
nuove terapie efficaci per questi pazienti. EPZ-
5676 è un inibitore di DOT1L, metiltranferasi con attività
leucemogenica in presenza di riarrangiamenti di
MLL (MLL-r). Sorafenib è un inibitore di tirosino-chinasi,
tra cui FLT3, frequentemente utilizzato nel trattamento
dei pazienti MLL-r. Scopo dello studio è la valutazione
degli effetti citotossici e biologici della combinazione
EPZ-5676 e Sorafenib. Sono state utilizzate
linee cellulari con o senza MLL-r, e cellule primarie
ottenute da pazienti AML pediatrici con MLL-r. Sono
stati valutati gli effetti citotossici e biologici dei singoli
farmaci e della loro combinazione mediante analisi citofluorimetriche,
Western Blotting e RQ-PCR. EPZ-5676
inibisce DOT1L inducendo demetilazione del target
H3k79 in tutte le cellule, ma la proliferazione cellulare
è significativamente inibita solo nelle cellule MOLM13
e nOMO1 (MLL-r) e OCI-AML3 (non MLL-r). Ciò si
associa ad induzione dell’apoptosi o effetti citostatici.
EPZ-5676 riduce l’espressione dei geni HOXA9,
MEIS1 e FLT3 in tutte le cellule; STAT5 e c-Myc nelle
cellule MLL-r. Inoltre, EPZ-5676 modula parzialmente
le vie di sopravvivenza PI3k/Akt e MAPk. La combinazione
EPZ-5676 e Sorafenib risulta sinergica nelle
linee cellulari (anche in assenza di MLL-r) e nelle cellule
primarie, in cui induce un significativo incremento
dell’apoptosi. In conclusione, gli effetti di EPZ-5676
non sembrano dipendere esclusivamente dalla presenza
di MLL-r. Inoltre, EPZ-5676 è sinergico con Sorafenib,
suggerendo un nuovo approccio terapeutico per il trattamento
dei pazienti pediatrici affetti da AML
KMT domain-focused CRISPR indel mutagenesis reveals a DOT1L allele that confers resistance to EPZ-5676 mediated growth arrest.
No full text(A) Schematic of the vector used to derive clonal MLL-AF9; NrasG12D leukemia RN2c cells that express a human codon-optimized S. pyogenes Cas9 (hCas9) and the vectors used for lentiviral sgRNA transduction. A GFP reporter was used where indicated to track sgRNA positive selection. LTR: long terminal repeat promoter, PGK: phosphoglycerate kinase 1 promoter, Puro: puromycin resistance gene, U6: a Pol III-driven promoter, sgRNA: chimeric single guide RNA, EFS: EF1α promoter, GFP: green fluorescent protein. (B) Schematic of DOT1L protein domain. A library of 73 sgRNAs was designed targeting the KMT domain of DOT1L. The DOT1L inhibitor EPZ-5676 targets the KMT domain. KMT, lysine methyltransferase. (C) Experimental workflow of domain-focused CRISPR indel mutagenesis screening. A pooled sgRNA library targeting the DOT1L KMT domain was introduced to RN2c via lentiviral transduction, followed by continuous exposure to EPZ-5676. Genomic DNA of indicated cell populations was isolated and harvested for sgRNA cassette quantification and sgRNA-induced indel identification by deep sequencing. (D) CRISPR indel mutagenesis genetic screening of DOT1L identified EPZ-5676 resistant mutants. The RN2c cells were treated with EPZ-5676 at day 3 post-transduction, in which a fraction of the cells was harvested and used as a reference time point (day 0). Cells were initially treated with 100 nM of EPZ-5676 at day 0. The inhibitor dosage was increased to 500 nM at day 20. At day 41, an EPZ-5676 resistant GFP+/sgRNA+ population was identified, harvested, and saved for subsequent deep sequencing experiments. (E) Quantitative reverse transcription PCR (qRT–PCR) of relative mRNA expression levels in parental and EPZ-5676 resistant RN2c cell lines after a 6-day treatment with indicated the concentration of EPZ-5676 or DMSO. Results were normalized to Gapdh, with the relative mRNA level in the DMSO-treated cells set to 1 (n = 3). (F) Pie charts of the relative abundance for 73 individual sgRNAs at indicated time points. Each slice represents the abundance of a single sgRNA. At day 0 (left), all 73 sgRNAs targeting the DOT1L KMT domain were detected at roughly equal abundance. At day 41 (right), DOT1L sgRNA #47 dominated the population, representing >95% of the GFP-positive cells. (G) A proliferation competition assay of RN2c cells transduced with indicated sgRNAs under the treatment of EPZ-5676 or DMSO shows that DOT1L sgRNA #47 induced mutant(s) confer resistance to EPZ-5676. An sgRNA targeting a Rosa locus and a random sgRNA targeting the DOT1L KMT domain (DOT1L sgRNA #64) served as negative controls. (H) Nucleotide and protein sequence diagram of the wild-type and DOT1L mutation induced by sgRNA #47 CRISPR mutagenesis under the treatment of EPZ-5676. Indel mutations were observed flanking the sgRNA cut site in exon 8 of DOT1L. The indel mutation corresponded to a VVEL to MM mutation at residue 293. (I) The effect of ectopic overexpression of DOT1L wild-type or mutant on RN2c cell proliferation under the treatment of EPZ-5676. RN2c cells were retrovirally transduced with wild-type or mutant human DOT1L cDNA. After a 9-day drug treatment, the relative cell accumulation corresponding to each indicated EPZ-5676 concentrations was measured and normalized to the DMSO treated cells (n = 3). All error bars shown represent s.e.m.</p
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
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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