105 research outputs found

    Expression of cell cycle regulators and frequency of TP53 mutations in high risk gastrointestinal stromal tumors prior to adjuvant imatinib treatment

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    Despite of multitude investigations no reliable prognostic immunohistochemical biomarkers in GIST have been established so far with added value to predict the recurrence risk of high risk GIST besides mitotic count, primary location and size. In this study, we analyzed the prognostic relevance of eight cell cycle and apoptosis modulators and of TP53 mutations for prognosis in GIST with high risk of recurrence prior to adjuvant treatment with imatinib. In total, 400 patients with high risk for GIST recurrence were randomly assigned for adjuvant imatinib either for one or for three years following laparotomy. 320 primary tumor samples with available tumor tissue were immunohistochemically analyzed prior to treatment for the expression of cell cycle regulators and apoptosis modulators cyclin D1, p21, p16, CDK4, E2F1, MDM2, p53 and p-RB1. TP53 mutational analysis was possible in 245 cases. A high expression of CDK4 was observed in 32.8% of all cases and was associated with a favorable recurrence free survival (RFS), whereas high expression of MDM2 (12.2%) or p53 (35.3%) was associated with a shorter RFS. These results were independent from the primary KIT or PDGFRA mutation. In GISTs with higher mitotic counts was a significantly increased expression of cyclin D1, p53 and E2F1. The expression of p16 and E2F1 significantly correlated to a non-gastric localization. Furthermore, we observed a significant higher expression of p21 and E2F1 in KIT mutant GISTs compared to PDGFRA mutant and wt GISTs. The overall frequency of TP53 mutations was low (n = 8; 3.5%) and could not be predicted by the immunohistochemical expression of p53. In summary, mutation analysis in TP53 plays a minor role in the subgroup of high-risk GIST before adjuvant treatment with imatinib. Strong expression of MDM2 and p53 correlated with a shorter recurrence free survival, whereas a strong expression of CDK4 correlated to a better recurrence free survival.Peer reviewe

    Scanning transmission electron microscopy strain measurement from millisecond frames of a direct electron charge coupled device

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    A high-speed direct electron detection system is introduced to the field of transmission electron microscopy and applied to strain measurements in semiconductor nanostructures. In particular, a focused electron probe with a diameter of 0.5 nm was scanned over a fourfold quantum layer stack with alternating compressive and tensile strain and diffracted discs have been recorded on a scintillator-free direct electron detector with a frame time of 1 ms. We show that the applied algorithms can accurately detect Bragg beam positions despite a significant point spread each 300 kV electron causes during detection on the scintillator-free camera. For millisecond exposures, we find that strain can be measured with a precision of 1.3  × 10−3, enabling, e.g., strain mapping in a 100×100 nm2 region with 0.5 nm resolution in 40 s

    Development of a core descriptor set for Crohn's anal fistula

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    AIM: Crohn's anal fistula (CAF) is a complex condition, with no agreement on which patient characteristics should be routinely reported in studies. The aim of this study was to develop a core descriptor set of key patient characteristics for reporting in all CAF research. METHOD: Candidate descriptors were generated from published literature and stakeholder suggestions. Colorectal surgeons, gastroenterologists and specialist nurses in inflammatory bowel disease took part in three rounds of an international modified Delphi process using nine-point Likert scales to rank the importance of descriptors. Feedback was provided between rounds to allow refinement of the next ratings. Patterns in descriptor voting were assessed using principal component analysis (PCA). Resulting PCA groups were used to organize items in rounds two and three. Consensus descriptors were submitted to a patient panel for feedback. Items meeting predetermined thresholds were included in the final set and ratified at the consensus meeting. RESULTS: One hundred and thirty three respondents from 22 countries completed round one, of whom 67.0% completed round three. Ninety seven descriptors were rated across three rounds in 11 PCA-based groups. Forty descriptors were shortlisted. The consensus meeting ratified a core descriptor set of 37 descriptors within six domains: fistula anatomy, current disease activity and phenotype, risk factors, medical interventions for CAF, surgical interventions for CAF, and patient symptoms and impact on quality of life. CONCLUSION: The core descriptor set proposed for all future CAF research reflects characteristics important to gastroenterologists and surgeons. This might aid transparent reporting in future studies

    Risk of hyperkalemia and combined use of spironolactone and long-term ACE inhibitor/angiotensin receptor blocker therapy in heart failure using real-life data: a population- and insurance-based cohort

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    PurposeClinical trials and few observational studies report increased hyperkalemia risks in heart failure patients receiving aldosterone blockers in addition to standard therapy. The aim of this study is to assess the hyperkalemia risk and combined use of spironolactone and long-term ACE (angiotensin-converting enzyme) inhibitor/angiotensin receptor blocker (ARB) therapy for heart failure in a real-life setting of a heterogeneous population. MethodsUsing claims data of the statutory health insurance fund AOK, covering 30% of the German population, we performed a nested case-control study in a cohort of heart failure patients receiving continuous ACE/ARB therapy (n=1,491,894). Hyperkalemia risk associated with concurrent use of spironolactone and ACE/ARB was calculated by conditional logistic regression in 1062 cases and 10,620 risk-set-sampling-matched controls. ResultsRisk of hyperkalemia in heart failure patients was significantly associated with spironolactone use (odds ratio (OR) (95% confidence interval (CI))=13.59 (11.63-15.88) in all and 11.05 (8.67-14.08) in those with information on New York Heart Association (NYHA) stage of disease). In the NYHA subpopulation, higher risk estimates were observed in short-term as compared with long-term users (OR (95%CI)=13.00 (9.82-17.21) and 9.12 (6.78-12.26), respectively). Moreover, the association was stronger in older (70years of age) as compared with younger patients (<70years of age) (OR (95%CI)=12.32 (9.35-16.23) and 8.73 (5.05-15.08), respectively), although interaction was not significant (p(interaction)=0.07). ConclusionsHyperkalemia risk associated with combined use of spironolactone and ACE/ARB is much stronger in real-life practice than observed in clinical trials. Careful potassium level monitoring in concomitant users of spironolactone and ACE/ARB is necessary. Copyright (c) 2015 John Wiley & Sons, Ltd
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