60 research outputs found

    Systems and technologies for objective evaluation of technical skills in laparoscopic surgery

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    Minimally invasive surgery is a highly demanding surgical approach regarding technical requirements for the surgeon, who must be trained in order to perform a safe surgical intervention. Traditional surgical education in minimally invasive surgery is commonly based on subjective criteria to quantify and evaluate surgical abilities, which could be potentially unsafe for the patient. Authors, surgeons and associations are increasingly demanding the development of more objective assessment tools that can accredit surgeons as technically competent. This paper describes the state of the art in objective assessment methods of surgical skills. It gives an overview on assessment systems based on structured checklists and rating scales, surgical simulators, and instrument motion analysis. As a future work, an objective and automatic assessment method of surgical skills should be standardized as a means towards proficiency-based curricula for training in laparoscopic surgery and its certification

    Promoter-bound METTL3 maintains myeloid leukaemia by m6A-dependent translation control.

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    N6-methyladenosine (m6A) is an abundant internal RNA modification in both coding and non-coding RNAs that is catalysed by the METTL3-METTL14 methyltransferase complex. However, the specific role of these enzymes in cancer is still largely unknown. Here we define a pathway that is specific for METTL3 and is implicated in the maintenance of a leukaemic state. We identify METTL3 as an essential gene for growth of acute myeloid leukaemia cells in two distinct genetic screens. Downregulation of METTL3 results in cell cycle arrest, differentiation of leukaemic cells and failure to establish leukaemia in immunodeficient mice. We show that METTL3, independently of METTL14, associates with chromatin and localizes to the transcriptional start sites of active genes. The vast majority of these genes have the CAATT-box binding protein CEBPZ present at the transcriptional start site, and this is required for recruitment of METTL3 to chromatin. Promoter-bound METTL3 induces m6A modification within the coding region of the associated mRNA transcript, and enhances its translation by relieving ribosome stalling. We show that genes regulated by METTL3 in this way are necessary for acute myeloid leukaemia. Together, these data define METTL3 as a regulator of a chromatin-based pathway that is necessary for maintenance of the leukaemic state and identify this enzyme as a potential therapeutic target for acute myeloid leukaemia

    Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

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    37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe

    Distinct expression patterns of the transcription factor E2F-1 in relation to tumour growth parameters in common human carcinomas

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    E2F-1 is a pivotal transcription factor that integrates signals from a variety of G1/S phase regulators and modulates diverse cellular functions, such as DNA synthesis, repair, mitosis, and apoptosis. Its role in cellular proliferation and apoptosis, as depicted from experimental models and limited reports in human malignancies, remains a matter of debate. Recently, in non-small cell lung cancer, it was observed that E2F-1 overexpression was associated with tumour growth, implying an ‘oncogenic’ effect. To clarify further the role of E2F-1 in carcinogenesis, the investigation was expanded in four of the most common human malignancies by examining its expression status and putative impact on tumour kinetics. These issues were addressed by immunohistochemical and molecular means in 52 breast carcinomas, 42 prostate adenocarcinomas, 58 colon adenocarcinomas, and 77 superficial bladder transitional cell carcinomas (TCCs). The following results were found: (i) in breast carcinomas, E2F-1 expression correlated with proliferation (p < 0.001) and growth index (p = 0.001); (ii) in prostate adenocarcinomas, absence of E2F-1 was noted, in contrast to its expression in normal and hyperplastic glands; (iii) in colon adenocarcinomas, E2F-1 expression was inversely related to growth index (p = 0.001), being expressed in lesions with increased apoptosis (p = 0.001) and low proliferation (p < 0.001); and i in superficial TCCs, E2F-1 expression correlated with proliferation (p = 0.002). Taken together, these results suggest that E2F-1 has a growth-promoting effect in breast carcinomas and superficial TCC, whereas the opposite seems to be the case for colon and prostate cancer. To interpret the above findings, the status of the pRb and p53 tumour suppressor pathways, which are known to affect E2F-1 activity, was further investigated. The results suggest that the actions of E2F-1 are mainly dependent on the functionality of these pathways. Nevertheless, the data also imply that p53-independent pathways may play a nodal role in the function of E2F-1 in colon cancer. Copyright (C) 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley Sons, Ltd

    Overexpression of the replication licensing regulators hCdt1 and hCdc6 characterizes a subset of non-small-cell lung carcinomas - Synergistic effect with mutant p53 on tumor growth and chromosomal instability - Evidence of E2F-1 transcriptional control over hCdt1

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    Replication licensing ensures once per cell cycle replication and is essential for genome stability. Overexpression of two key licensing factors, Cdc6 and Cdt1, leads to overreplication and chromosomal instability (CIN) in lower eukaryotes and recently in human cell lines. In this report, we analyzed hCdt1, hCdc6, and hGeminin, the hCdt1 inhibitor expression, in a series of non-small-cell lung carcinomas, and investigated for putative relations with G(1)/S phase regulators, tumor kinetics, and ploidy. This is the first study of these fundamental licensing elements in primary human lung carcinomas. We herein demonstrate elevated levels (more than fourfold) of hCdt1 and hCdc6 in 43% and 50% of neoplasms, respectively, whereas aberrant expression of hGeminin was observed in 49% of cases (underexpression, 12%; overexpression, 37%). hCdt1 expression positively correlated with hCdc6 and E2F-1 levels (P = 0.001 and P = 0.048, respectively). Supportive of the observed link between E2F-1 and hCdt1, we provide evidence that E2F-1 up-regulates the hCdt1 promoter in cultured mammalian cells. Interestingly, hGeminin overexpression was statistically related to increased hCdt1 levels (P = 0.025). Regarding the kinetic and ploidy status of hCdt1- and/or hCdc6-overexpressing tumors, p53-mutant cases exhibited significantly increased tumor growth values (Growth index; GI) and aneuploidy/CIN compared to those bearing intact p53 (P = 0.008 for GI, P = 0.001 for CIN). The significance of these results was underscored by the fact that the latter parameters were independent of p53 within the hCdt1-hCdc6 normally expressing cases. Cumulatively, the above suggest a synergistic effect between hCdt1-hCdc6 overexpression and mutant-P53 over tumor growth and CIN in non-small-cell. lung carcinomas
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