581 research outputs found
A reciprocal repression between ZEB1 and members of the miR-200 family promotes EMT and invasion in cancer cells
The embryonic programme ‘epithelial–mesenchymal transition' (EMT) is thought to promote malignant tumour progression. The transcriptional repressor zinc-finger E-box binding homeobox 1 (ZEB1) is a crucial inducer of EMT in various human tumours, and was recently shown to promote invasion and metastasis of tumour cells. Here, we report that ZEB1 directly suppresses transcription of microRNA-200 family members miR-141 and miR-200c, which strongly activate epithelial differentiation in pancreatic, colorectal and breast cancer cells. Notably, the EMT activators transforming growth factor β2 and ZEB1 are the predominant targets downregulated by these microRNAs. These results indicate that ZEB1 triggers an microRNA-mediated feedforward loop that stabilizes EMT and promotes invasion of cancer cells. Alternatively, depending on the environmental trigger, this loop might switch and induce epithelial differentiation, and thus explain the strong intratumorous heterogeneity observed in many human cancers
D-optimal designs via a cocktail algorithm
A fast new algorithm is proposed for numerical computation of (approximate)
D-optimal designs. This "cocktail algorithm" extends the well-known vertex
direction method (VDM; Fedorov 1972) and the multiplicative algorithm (Silvey,
Titterington and Torsney, 1978), and shares their simplicity and monotonic
convergence properties. Numerical examples show that the cocktail algorithm can
lead to dramatically improved speed, sometimes by orders of magnitude, relative
to either the multiplicative algorithm or the vertex exchange method (a variant
of VDM). Key to the improved speed is a new nearest neighbor exchange strategy,
which acts locally and complements the global effect of the multiplicative
algorithm. Possible extensions to related problems such as nonparametric
maximum likelihood estimation are mentioned.Comment: A number of changes after accounting for the referees' comments
including new examples in Section 4 and more detailed explanations throughou
A Comprehensive Molecular Characterization of the Pancreatic Neuroendocrine Tumor Cell Lines BON-1 and QGP-1
Experimental models of neuroendocrine tumor disease are scarce, with only a few existing neuroendocrine tumor cell lines of pancreatic origin (panNET). Their molecular characterization has so far focused on the neuroendocrine phenotype and cancer-related mutations, while a transcription-based assessment of their developmental origin and malignant potential is lacking. In this study, we performed immunoblotting and qPCR analysis of neuroendocrine, epithelial, developmental endocrine-related genes as well as next-generation sequencing (NGS) analysis of microRNAs (miRs) on three panNET cell lines, BON-1, QGP-1, and NT-3. All three lines displayed a neuroendocrine and epithelial phenotype; however, while insulinoma-derived NT-3 cells preferentially expressed markers of mature functional pancreatic β-cells (i.e., INS, MAFA), both BON-1 and QGP-1 displayed high expression of genes associated with immature or non-functional β/δ-cells genes (i.e., NEUROG3), or pancreatic endocrine progenitors (i.e., FOXA2). NGS-based identification of miRs in BON-1 and QGP-1 cells revealed the presence of all six members of the miR-17-92 cluster, which have been implicated in b-cell function and differentiation, but also have roles in cancer being both oncogenic or tumor suppressive. Notably, both BON-1 and QGP-1 cells expressed several miRs known to be negatively associated with epithelial-mesenchymal transition, invasion or metastasis. Moreover, both cell lines failed to exhibit migratory activity in vitro. Taken together, NT-3 cells resemble mature functional β-cells, while both BON-1 and QGP-1 are more similar to immature/non-functional pancreatic β/δ-cells or pancreatic endocrine progenitors. Based on the recent identification of three transcriptional subtypes in panNETs, NT-3 cells resemble the "islet/insulinoma tumors" (IT) subtype, while BON-1 and QGP-1 cells were tentatively classified as "metastasis-like/primary" (MLP). Our results provide a comprehensive characterization of three panNET cell lines and demonstrate their relevance as neuroendocrine tumor models
Закономерности изменения физико-механических свойств сплава Zr-1%Nb при комплексном ионно-плазменном модифицировании поверхности и наводороживании
В работе были изучены особенности изменения морфологии, структуры и физико-механических свойств циркониевого сплава Zr-1%Nb, подвергнутого комплексному ионно-плазменному модифицированию поверхности методами плазменно-иммерсионной ионной имплантации титана и осаждения покрытий нитрида титана. Показана высокая эффективность защиты сформированных структур от проникновения водорода в циркониевый сплав. Изучены механизмы сорбции и захвата водорода в титансодержащем модифицированном слое.In the present work, the features of the change in the morphology, structure, and physico-mechanical properties of zirconium alloy Zr-1%Nb subjected to complex ion-plasma surface modification by the methods of plasma-immersion titanium ion implantation and deposition of titanium nitride coatings were studied. The high protective properties of the formed structures against hydrogen permeation into the zirconium alloy is shown. Mechanisms of sorption and capture of hydrogen in a titanium-doped modified layer are studied
Ideal Outcome After Pancreatoduodenectomy:A Transatlantic Evaluation of a Harmonized Composite Outcome Measure
OBJECTIVE: The aim of this study is to define and assess Ideal Outcome in the national or multicenter registries of North America, Germany, the Netherlands, and Sweden. BACKGROUND: Assessing outcomes after pancreatoduodenectomy among centers and countries requires a broad evaluation that cannot be captured by a single parameter. Previously, 2 composite outcome measures (textbook outcome and optimal pancreatic surgery) for pancreatoduodenectomy have been described from Europe and the United States. These composites were harmonized into ideal outcome (IO). METHODS: This analysis is a transatlantic retrospective study (2018-2020) of patients after pancreatoduodenectomy within the registries from North America, Germany, The Netherlands, and Sweden. After 3 consensus meetings, IO for pancreatoduodenectomy was defined as the absence of all 6 parameters: (1) in-hospital mortality, (2) severe complications-Clavien-Dindo ≥3, (3) postoperative pancreatic fistula-International Study Group of Pancreatic Surgery (ISGPS) grade B/C, (4) reoperation, (5) hospital stay >75th percentile, and (6) readmission. Outcomes were evaluated using relative largest difference (RLD) and absolute largest difference (ALD), and multivariate regression models. RESULTS: Overall, 21,036 patients after pancreatoduodenectomy were included, of whom 11,194 (54%) reached IO. The rate of IO varied between 55% in North America, 53% in Germany, 52% in The Netherlands, and 54% in Sweden (RLD: 1.1, ALD: 3%, P <0.001). Individual components varied with an ALD of 2% length of stay, 4% for in-hospital mortality, 12% severe complications, 10% postoperative pancreatic fistula, 11% reoperation, and 9% readmission. Age, sex, absence of chronic obstructive pulmonary disease, body mass index, performance status, American Society of Anesthesiologists (ASA) score, biliary drainage, absence of vascular resection, and histologic diagnosis were associated with IO. In the subgroup of patients with pancreatic adenocarcinoma, country, and neoadjuvant chemotherapy also was associated with improved IO. CONCLUSIONS: The newly developed composite outcome measure "Ideal Outcome" can be used for auditing and comparing outcomes after pancreatoduodenectomy. The observed differences can be used to guide collaborative initiatives to further improve the outcomes of pancreatic surgery.</p
Transatlantic registries of pancreatic surgery in the United States of America, Germany, the Netherlands, and Sweden: Comparing design, variables, patients, treatment strategies, and outcomes
Background: Registries of pancreatic surgery have become increasingly popular as they facilitate both quality improvement and clinical research. We aimed to compare registries for design, variables collected, patient characteristics, treatment strategies, clinical outcomes, and pathology. Methods: Registered variables and outcomes of pancreatoduodenectomy (2014–2017) in 4 nationwide or multicenter pancreatic surgery registries from the United States of America (American College of Surgeons National Surgical Quality Improvement Program), Germany (Deutsche Gesellschaft für Allgemein- und Viszeralchirurgie - Studien-, Dokumentations- und Qualitätszentrum), the Netherlands (Dutch Pancreatic Cancer Audit), and Sweden (Swedish National Pancreatic and Periampullary Cancer Registry) were compared. A core registry set of 55 parameters was identified and evaluated using relative and absolute largest differences between extremes (smallest versus largest). Results: Overall, 22,983 pancreatoduodenectomies were included (15,224, 3,558, 2,795, and 1,406 in the United States of America, Germany, the Netherlands, and Sweden). Design of the registries varied because 20 out of 55 (36.4%) core parameters were not available in 1 or more registries. Preoperative chemotherapy in patients with pancreatic ductal adenocarcinoma was administered in 27.6%, 4.9%, 7.0%, and 3.4% (relative largest difference 8.1, absolute largest difference 24.2%, P < .001). Minimally invasive surgery was performed in 7.8%, 4.5%, 13.5%, and unknown (relative largest difference 3.0, absolute largest difference 9.0%, P < .001). Median length of stay was 8.0, 16.0, 12.0, and 11.0 days (relative largest difference 2.0, absolute largest difference 8.0, P < .001). Reoperation was performed in 5.7%, 17.1%, 8.7%, and 11.2% (relative largest difference 3.0, absolute largest difference 11.4%, P < .001). In-hospital mortality was 1.3%, 4.7%, 3.6%, and 2.7% (relative largest difference 3.6, absolute largest difference 3.4%, P < .001). Conclusion: Considerable differences exist in the design, variables, patients, treatment strategies, and outcomes in 4 Western registries of pancreatic surgery. The absolute largest differences of 24.3% for the use of preoperative chemotherapy, 9.0% for minimally invasive surgery, 11.4% for reoperation rate, and 3.4% for in-hospital mortality require further study and improvement. This analysis provides 55 core parameters for pancreatic surgery registries
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