1,720,984 research outputs found
Replication, checkpoint suppression and structure of centromeric DNA
Full text linkHuman centromeres contain large amounts of repetitive DNA sequences known as α satellite DNA, which can be difficult to replicate and whose functional role is unclear. Recently, we have characterized protein composition, structural organization and checkpoint response to stalled replication forks of centromeric chromatin reconstituted in Xenopus laevis egg extract. We showed that centromeric DNA has high affinity for SMC2-4 subunits of condensins and for CENP-A, it is enriched for DNA repair factors and suppresses the ATR checkpoint to ensure its efficient replication. We also showed that centromeric chromatin forms condensins enriched and topologically constrained DNA loops, which likely contribute to the overall structure of the centromere. These findings have important implications on how chromosomes are organized and genome stability is maintained in mammalian cells
Traduzione e validazione in italiano della Behavioral Pain Scale (BPS) per la valutazione del dolore in pazienti incoscienti e sedati
No full textIntroduzione: la valutazione del dolore in terapia intensiva non è sempre possibile, principalmente perchè i pazienti sono spesso in uno stato d’incoscienza o coma. La letteratura indica la scala Behavioral Pain Scale (BPS) come strumento adatto a valutare il dolore nei pazienti critici sedati. Il punteggio si basa su osservazioni che riguardano le espressioni facciali, i movimenti degli arti e l’adattamento alla ventilazione. Lo strumento non è ancora stato validato in italiano. L’articolo presenta la preparazione e validazione della versione italiana della BPS (BPS-ITA).
Materiali e metodi: la scala è stata sottoposta a back-translation e inviata all’autore originale per un parere. Quattro infermieri esperti hanno valutato la validità di contenuto e facciata. L’autore dello studio e gli infermieri di una terapia intensiva hanno applicato la scala ad 11 pazienti, raccogliendo i dati all’ammissione, prima di una procedura dolorosa e di una non dolorosa, e dopo le procedure stesse.
Risultati: sono state effettuate 194 osservazioni. La BPS-ITA ha mostrato buona stabilità (rho=0.789, p<0.001), ottima affidabilità intervalutatore (k=0.945) e buona omogeneità (alpha=0.8), consentendo una netta distinzione tra pazienti sedati e non sedati.
Discussione: la BPS italiana consente un’affidabile valutazione del dolore nei pazienti sedati. Il numero di osservazioni ha parzialmente compensato la modesta ampiezza campionaria.
Conclusioni: la BPS italiana è valida e affidabile nel misurare il dolore nei pazienti sedati non tetraplegici. Semplifica l’accertamento e può migliorare la gestione complessiva del dolore e la qualità dell’assistenza.Background: the assessment of pain in an Intensive Care Unit (ICU) is not always possible, mainly because patients are often in a state of unconsciousness or coma. The literature indicates the Behavioral Pain Scale (BPS) as a good tool for assessing pain in sedated, critically ill patients. The score is based upon observations regarding facial expressions, limb movements, and compliance to ventilation. The scale has not yet been translated into Italian. Aim: to test the validity and reliability of the Italian version of the Behavioral Pain Scale (BPS). Methods: we back-translated the scale, and submitted it to the original author. Four experienced nurses assessed its content and face validity. The author of this study and the nurses of an ICU applied the scale to eleven patients, performing assessments at the admission and before and after a painful and a painless procedure, for each patient.
Results: 194 observations were collected in the ICU. The Italian scale showed good stability (Spearmanís rho=0.789, p<0.001), excellent interrater reliability (Cohenís Kappa=0.945) and good homogeneity (Cronbachís alpha=0.8), and allowed clear separation between sedated and non-sedated patients. Discussion: the Italian version of the BPS will allow reliable assessment of pain In sedated patients. The number of observation partially remedied the limit of the small sample size. Conclusion: The Italian version of the scale is valid and reliable for measuring pain in sedated, non-quadriplegic critically ill patients. The BPS simplifies pain assessment in this patients and can improve overall pain management and quality of care
Epigenetic regulation of replication origins
No full textReplication origin density of Xenopus laevis embryonic cells is higher than somatic ones. This ensures rapid and accurate genome duplication during embryonic cell divisions. Close to the mid-blastula transition (MBT), the density of replication origins reverts to the somatic one, initiation of DNA replication becomes restricted to specific sites and correlates with cell cycle lengthening. Intriguingly, in nuclear transfer experiments exposure of somatic nuclei to egg cytoplasm is sufficient to convert the somatic origin density to the embryonic one, suggesting that the replication origin assembly in somatic cells is restrained by epigenetic factors modifiable by the egg cytoplasm. we performed extensive biochemical fraction of egg cytoplasm to identify factors that regulate replication origin density in embryonic and somatic nuclei. this effort led to the isolation of SSRP1 as major factor that stimulates somatic nuclei replication in egg extract. we showed that exposure of somatic nuclei to SSRP1 removes epigenetic determinants that restrain replication origin assembly and restores replication origin density typical of embryonic nuclei on somatic chromatin. Strikingly, SSRP1-mediated regulation of replication origin assembly has a dramatic impact on cell cycle progression and early embryonic development. These results and their implications will be described in details in the context of more general regulation of DNA replication of vertebrate organisms
Epigenetic regulation of eukaryotic DNA replication origins
No full textIn higher eukaryotes, DNA replication initiates at multiple sites distributed along the
chromosome, called replication origins. The location and timing of these initiation events are
developmentally and epigenetically regulated. In the early Xenopus embryos replication
origins are more abundant than in somatic cells, or at later stages of development. This
particular organization of the replicon ensures rapid and accurate genome duplication during
early embryonic cell divisions. Close to the mid-blastula transition (MBT), the density of
replication origins declines, initiation of DNA replication becomes restricted to specific sites
and correlates with cell cycle lengthening. Intriguingly, in nuclear transfer
experiments exposure of somatic nuclei to egg cytoplasm is sufficient to convert the somatic
origin density to the embryonic one, suggesting that the replication origin assembly in somatic
cells is restrained by epigenetic factors modifiable by the egg cytoplasm. We performed
extensive biochemical fraction of egg cytoplasm to identify factors that regulate replication
origin density in embryonic and somatic nuclei. This effort led to the isolation of SSRP1 as
major factor that stimulates somatic nuclei replication in egg extract. We showed that
exposure of somatic nuclei to SSRP1 removes epigenetic determinants that restrain
replication origin assembly and restores replication origin density typical of embryonic nuclei
on somatic chromatin. Strikingly, SSRP1-mediated regulation of replication origin assembly
has a dramatic impact on cell cycle progression and early embryonic development. These
results and their implications will be described in details in the context of more general
regulation of DNA replication in vertebrate organisms
Co-Simulazione meccatronica di una piattaforma di lavoro elevabile con braccio articolato
No full text
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
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