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Caratterizzazione molecolare mediante array-CGH e origine parentale di anomalie cromosomiche strutturali in pazienti con ritardo mentale/psicomotorio/autismo e/o anomalie comportamentali
Full text linkThe study of structural chromosomal abnormalities has emerged in recent years as a powerful tool for the identification of molecular causes underlying disorders responsible for genomic complex phenotypes such as mental retardation, autism, epilepsy, psychiatric disorders and multiple congenital anomalies.
For nearly 10 years it has increasingly become clear that the conventional cytogenetic analysis is unable to detect chromosomal abnormalities less than 5-10 Mb, that may be associated with phenotypic abnormalities and mental retardation.
This limit has been exceeded in recent years by the introduction of a molecular cytogenetic technique, array-CGH, which allows complete and precise analysis of DNA copy number variations and allows to evaluate with high specificity many chromosomal regions in order to detect chromosomal imbalances.
Over the last decade with the introduction of genome wide array, it became clear that the molecular mechanisms at the basis of the genomic disorders are related to rearrangements of some regions of the genome, particularly predisposed to aberrant recombination.
Several studies have indeed revealed the presence of some segments (SINE, LINE, LCRS) that cause a high degree of genomic instability leading to chromosomal rearrangements.
The parental origin of chromosome abnormalities is of considerable interest because it may help to understand their formation mechanism.
Many studies show that male gametogenesis appears susceptible to the formation of structural chromosome abnormalities. This is generally attributed to the much larger number of premeiotic cell divisions undergone by male germ cells in comparison with female germ cells.
In this study 66 subjects with mental retardation and / or development, autism, multiple congenital anomalies and dimorphisms were assessed by array CGH, in order to verify the presence of cryptic chromosomal rearrangements and to characterize more precisely the chromosomal abnormalities identified by high-resolution chromosome examination.
It was then analyzed the parental origin of chromosome rearrangements by use of polymorphic markers (RFLP or STR) to determine whether there is a different mutation rate in both sexes. Finally the breakpoints were analyzed to verify the presence of homologous regions which may predisposed to rearrangements.
The results obtained in this study show that 16% of patients with clinical signs and a normal karyotype have a cryptic deletion / duplication. In 20% of patients with karyotypic alterations, previously identified by standard cytogenetic, array- CGH detected other abnormalities.
The analysis of the breakpoints revealed the presence of homologous regions that may have predisposed the rearrangement confirming that the architecture of the genome play a major role for genomic instability causing chromosomal rearrangements.
In contrast to the literature there are no significant differences between the sexes in the formation of chromosomal rearrangements.Lo studio delle anomalie cromosomiche strutturali si è affermato negli ultimi anni come un potente mezzo per l’identificazione delle cause molecolari alla base di disordini genomici responsabili di quadri fenotipici complessi quali ritardo mentale, autismo, epilessia, disordini psichiatrici e anomalie congenite multiple.
Da circa 10 anni è emerso sempre più chiaramente che l’analisi citogenetica convenzionale non è in grado di rilevare anomalie cromosomiche inferiori a 5-10 Mb che, seppur di dimensioni submicroscopiche, possono associarsi a ritardo mentale e anomalie fenotipiche.
Questo limite è stato da qualche anno superato dall’introduzione di una tecnica di citogenetica molecolare, l’array-CGH, che permette un’analisi completa e precisa delle variazioni del numero di copie delle sequenze di DNA e consente di valutare contemporaneamente e con alta specificità più regioni cromosomiche in modo da poter evidenziare sbilanciamenti.
Nell'ultimo decennio con l'introduzione di array genome wide, è risultato evidente che i meccanismi molecolari alla base dei disordini genomici sono correlati a riarrangiamenti di particolari regioni del genoma, suscettibili più di altre ad andare incontro a ricombinazioni aberranti.
Diversi studi hanno evidenziato infatti la presenza di alcuni segmenti (sequenze SINE, LINE, LCRs) che causano un alto grado di instabilità genomica portando a riarrangiamenti cromosomici.
L’origine parentale delle anomalie cromosomiche è di considerevole interesse in quanto potrebbe aiutare a capire il loro meccanismo di formazione.
Gli studi fatti fino ad ora riportano nella gametogenesi maschile c’è una maggiore tendenza alla formazione di riarrangiamenti cromosomici conseguente a un maggior numero di divisioni premeiotiche delle cellule germinali maschili rispetto a quelle femminili.
In questo studio sono stati valutati mediante array CGH 66 soggetti che presentano ritardo mentale e/o dello sviluppo, autismo, anomalie congenite multiple e dimorfismi con lo scopo di verificare la presenza di riarrangiamenti criptici e caratterizzare in modo più preciso le anomalie identificate grazie all’esame cromosomico ad alta definizione.
E’ stata quindi determinata l'origine parentale dei riarrangiamenti mediante l'utilizzo di marcatori polimorfici (STR o RFLP) per definire se esiste un diverso tasso di mutazione nei due sessi; infine sono stati analizzati i breakpoints per verificare la presenza di regioni di omologia che possano aver predisposto al riarrangiamento.
I risultati ottenuti in questo studio mostrano che il 16% dei pazienti con fenotipo patologico e cariotipo normale è portatore di una delezione/duplicazione criptica;
inoltre nel 20 % dei pazienti in cui erano state precedentemente individuate alterazioni del cariotipo, l’array-CGH ha evidenziato ulteriori anomalie.
L’analisi dei breakpoints ha evidenziato la presenza di regioni di omologia che possono aver favorito il riarrangiamento confermando che l’architettura del genoma agisce come catalizzatore dell’instabilità cromosomica causando riarrangiamenti genomici, tuttavia al contrario di quanto riportato in letteratura non ci sono differenze significative tra i due sessi nella formazione di riarrangiamenti cromosomici
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
Parent training associato a trattamento di gruppo con bambini con disturbi della lettura e della scrittura
No full text6q27 subtelomeric deletions: Is there a specific phenotype?
Full text linkWe read with great interest the report of Mosca et al. [2010] in theMay issue of the Journal, describing a patient with a 5.65Mb
deletion on chromosome 6q27 (ranging from 165.24Mb to the
6q telomere at 170.89 Mb)associated with intellectual disability and a Ehlers–Danlos (EDS) like phenotype. We would like to further delineate the phenotypic spectrum of these rearrangements by reporting two additional patients with this chromosomal abnormality.
Patient 1 is a 17-year-old girl, with a history of moderate
psychomotor retardation, hypotonia and a sacral lipoma, that was surgically removed at age 5. She had mild dysmorphic features (downslanting, narrow palpebral fissures, a broad nasal root, malar hypoplasia, prominent ears, and thin vermillion of the upper lip). Brain MRI performed at age 16 as part of the investigations for the intellectual disability, showed an atypical cerebellar cyst, and evidence of periventricular nodular heterotopia. She has never had seizures
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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