1,379 research outputs found
Impact of treatment planning target volumen (PTV) size on radiation induced diarrhoea following selenium supplementation in gynecologic radiation oncology - a subgroup analysis of a multicenter, phase III trial
Background: In a previous analysis (Int J Radiat Oncol Biol Phys 70:828-835,2010), we assessed whether an adjuvant supplementation with selenium (Se) improves Se status and reduces the radiation-induced side-effects of patients treated by adjuvant radiotherapy (RT) for cervical and uterine cancer. Now, a potential relation between the planning target volume (PTV) of the RT and the Se effect concerning radiation induced diarrhoea was evaluated in detail.
Methods: Whole blood Se concentrations had been measured in patients with cervical (n=11) and uterine cancer (n=70) after surgical treatment, during, and at the end of RT. Patients with initial Se concentrations of less than 84 ÎŒg/l were categorized as Se-deficient and randomized before RT to receive Se (as sodium selenite) per os on the days of RT, or to receive no supplement during RT. Diarrhoea was graded according to the Common Toxicity Criteria system (CTC, Version 2a). The evaluation of the PTV of the RT was ascertained with the help of a specialised computer-assisted treatment planning software used for radiation planning procedure.
Results: A total of 81 patients had been randomized for the initial supplementation study, 39 of which received Se [selenium group, SeG] and 42 serving as controls [control group, CG]. Mean Se levels did not differ between SeG and CG upon study initiation, but were significantly higher in the SeG compared to the CG at the end of RT. The actuarial incidence of at least CTC 2 radiation induced diarrhoea in the SeG was 20.5% compared to 44.5% in the CG (p=0.04). The median PTV in both groups was 1302 ml (916â4608). With a PTV of 1302 ml (n=40) the actuarial incidence of at least CTC 2 diarrhoea in the SeG was 19.1% (4 of 21 patients) versus 52.6% (10 of 19 patients) in the CG (p=0.046).
Conclusions: Se supplementation during RT was effective to improve blood Se status in Se-deficient cervical and uterine cancer patients, and reduces episodes and severity of RT-induced diarrhoea. This effect was most pronounced and significant in patients with large PTV (> 1302 ml)
α2C-Adrenoceptor polymorphism is associated with improved event-free survival in patients with dilated cardiomyopathy
Aims The sympathetic nervous system plays a central role in cardiac growth but its overstimulation is associated with increased mortality in patients with chronic heart failure. Pre-synaptic α2-adrenoceptors are essential feedback regulators to control the release of norepinephrine from sympathetic nerves. In this study we tested whether a deletion polymorphism in the human α2C-adrenoceptor gene (α2CDel322-325) affects progression of heart failure in patients with dilated cardiomyopathy (DCM). Methods and results We genotyped and phenotyped 345 patients presenting with DCM in the heart transplant unit of the German Heart Institute, starting in 1994. Patients were treated according to guidelines (99% ACEI, 76% ÎČ-blockers) and were followed until December 2002 or until a first event [death, heart transplantation, or implantation of a left ventricular assist device (LVAD) for a life-threatening condition] occurred. Mean follow-up time was 249 weeks (4.9â
years) in event-free patients and 104 weeks (2â
years) in patients with events. During follow-up, 51% of the patients exhibited an event: death (18%), implantation of LVAD as bridging for transplantation (7%), or heart transplantation (25%). By Kaplan-Meier analysis, DCM patients with the deletion variant Del322-325 in the α2C-adrenoceptor showed significantly decreased event rates (P=0.0043). Cox regression analysis revealed that the presence of the deletion was associated with reduced death rate (relative risk: 0.129, 95% CI: 0.18-0.9441, P=0.044) and event rates (relative risk: 0.167, 95% CI: 0.041-0.685, P=0.012). Conclusion α2C-Adrenoceptor deletion may be a novel, strong, and independent predictor of reduced event rates in DCM patients treated according to guideline
From Berlin-Dahlem to the Fronts of World War I: The Role of Fritz Haber and His Kaiser Wilhelm Institute in German Chemical Warfare
There is little doubt that Fritz Haber (1868â1934) was the driving force behind the centrally directed development of chemical warfare in Germany, whose use during World War I violated international law and elicited both immediate and enduring moral criticism. The chlorine cloud attack at Ypres on 22 April 1915 amounted to the first use of a weapon of mass destruction and as such marks a turning point in world history. Following the âsuccessâ at Ypres, Haber, eager to employ science in resolving the greatest strategic challenge of the warâthe stalemate of trench warfareâpromptly transformed his Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry in Berlin-Dahlem into a center for the development of chemical weapons and of protective measures against them. This article traces in some detail the path from Berlin-Dahlem to the fronts of World War I, lays out the indispensible role of Fritz Haber in German chemical warfare and provides a summary of his views on chemical weapons, which he never renounced
The Mother Centriole Plays an Instructive Role in Defining Cell Geometry
Centriole positioning is a key step in establishment and propagation of cell geometry, but the mechanism of this positioning is unknown. The ability of pre-existing centrioles to induce formation of new centrioles at a defined angle relative to themselves suggests they may have the capacity to transmit spatial information to their daughters. Using three-dimensional computer-aided analysis of cell morphology in Chlamydomonas, we identify six genes required for centriole positioning relative to overall cell polarity, four of which have known sequences. We show that the distal portion of the centriole is critical for positioning, and that the centriole positions the nucleus rather than vice versa. We obtain evidence that the daughter centriole is unable to respond to normal positioning cues and relies on the mother for positional information. Our results represent a clear example of âcytotaxisâ as defined by Sonneborn, and suggest that centrioles can play a key function in propagation of cellular geometry from one generation to the next. The genes documented here that are required for proper centriole positioning may represent a new class of ciliary disease genes, defects in which would be expected to cause disorganized ciliary position and impaired function
[11C]-l-Methionine positron emission tomography in the management of children and young adults with brain tumors
Only a few Methyl-[11C]-l-methionine (MET) positron emission tomography (PET) studies have focused on children and young adults with brain neoplasm. Due to radiation exposure, long scan acquisition time, and the need for sedation in young children MET-PET studies should be restricted to this group of patients when a decision for further therapy is not possible from routine diagnostic procedures alone, e.g., structural imaging. We investigated the diagnostic accuracy of MET-PET for the differentiation between tumorous and non-tumorous lesions in this group of patients. Forty eight MET-PET scans from 39 patients aged from 2 to 21 years (mean 15 ± 5.0 years) were analyzed. The MET tumor-uptake relative to a corresponding control region was calculated. A receiver operating characteristic (ROC) was performed to determine the MET-uptake value that best distinguishes tumorous from non-tumorous brain lesions. A differentiation between tumorous (n = 39) and non-tumorous brain lesions (n = 9) was possible at a threshold of 1.48 of relative MET-uptake with a sensitivity of 83% and a specificity of 92%, respectively. A differentiation between high grade malignant lesions (mean MET-uptake = 2.00 ± 0.46) and low grade tumors (mean MET-uptake = 1.84 ± 0.31) was not possible. There was a significant difference in MET-uptake between the histologically homogeneous subgroups of astrocytoma WHO grade II and anaplastic astrocytoma WHO grade III (P = 0.02). MET-PET might be a useful tool to differentiate tumorous from non-tumorous lesions in children and young adults when a decision for further therapy is difficult or impossible from routine structural imaging procedures alone
Religiosity and meditation practice: exploring their explanatory power on psychological adjustment
There has been increased interest in the relationships between religiosity, meditation practice and well-being, but there is lack of understanding as to how specific religious components and distinct meditation practices could influence different positive and negative psychological adjustment outcomes. The aim of this study was to assess the explanatory power of religious beliefs and the practice of prayer, focused attention (FA), open monitoring (OM), and compassion meditation (CM) on psychological adjustment, taking into consideration a number of practice-related variables such as session length, frequency of practice and lifetime practice. Psychological adjustment was assessed by means of happiness, positive affect, depression, negative affect, and emotional overproduction. A cross-sectional design was used, with a final sample comprising 210 Spanish participants who completed an online assessment protocol. Hierarchical regressions were performed, including age, sex and psychotropic medication use in the first step as possible confounders, with the addition of religious beliefs and the practice of prayer, FA, OM, and CM in the second step. FA session length was related to all psychological adjustment outcomes: happiness (ÎR 2 = 0.09, p = 0.002; ÎČ = 0.25, p = 0.001), positive affect (ÎR 2 = 0.09, p = 0.002; ÎČ = 0.18, p = 0.014), depression (ÎR2 = 0.07, p = 0.004; ÎČ = -0.27, p < 0.001), negative affect (ÎR 2 = 0.08, p = 0.007; ÎČ = -0.27, p < 0.001) and emotional overproduction (ÎR 2 = 0.07, p = 0.013; ÎČ = -0.23, p = 0.001). CM session length was related to positive affect (ÎČ = 0.18, p = 0.011). CM practice frequency was associated with happiness (ÎR 2 = 0.06, p = 0.038; ÎČ = 0.16, p = 0.041). Lifetime practice of FA was related to happiness (ÎR 2 = 0.08, p = 0.007; ÎČ = 0.21, p = 0.030) and OM to emotional overproduction (ÎR 2 = 0.08, p = 0.037; ÎČ = -0.19, p = 0.047). Religious beliefs and prayer seemed to be less relevant than meditation practices such as FA, OM, and CM in explaining psychological adjustment. The distinct meditation practices might be differentially related to distinct psychological adjustment outcomes through different practice-related variables. However, research into other forms of institutional religiosity integrating social aspects of religion is required
Signal extraction from movies of honeybee brain activity: the ImageBee plugin for KNIME
BACKGROUND: In the antennal lobe, a dedicated olfactory center of the honeybee brain, odours are encoded as activity patterns of coding units, the so-called glomeruli. Optical imaging with calcium-sensitive dyes allows us to record these activity patterns and to gain insight into olfactory information processing in the brain. METHOD: We introduce ImageBee, a plugin for the data analysis platform KNIME. ImageBee provides a variety of tools for processing optical imaging data. The main algorithm behind ImageBee is a matrix factorisation approach. Motivated by a data-specific, non-negative mixture model, the algorithm aims to select the generating extreme vectors of a convex cone that contains the data. It approximates the movie matrix by non-negative combinations of the extreme vectors. These correspond to pure glomerular signals that are not mixed with neighbour signals. RESULTS: Evaluation shows that the proposed algorithm can identify the relevant biological signals on imaging data from the honeybee AL, as well as it can recover implanted source signals from artificial data. CONCLUSIONS: ImageBee enables automated data processing and visualisation for optical imaging data from the insect AL. The modular implementation for KNIME offers a flexible platform for data analysis projects, where modules can be rearranged or added depending on the particular application. AVAILABILITY: ImageBee can be installed via the KNIME update service. Installation instructions are available at http://tech.knime.org/imagebee-analysing-imaging-data-from-the-honeybee-brain
Muon reconstruction and identification efficiency in ATLAS using the full Run 2 pp collision data set at \sqrt{s}=13 TeV
This article documents the muon reconstruction and identification efficiency obtained by the ATLAS experiment for 139 \hbox {fb}^{-1} of pp collision data at \sqrt{s}=13 TeV collected between 2015 and 2018 during Run 2 of the LHC. The increased instantaneous luminosity delivered by the LHC over this period required a reoptimisation of the criteria for the identification of prompt muons. Improved and newly developed algorithms were deployed to preserve high muon identification efficiency with a low misidentification rate and good momentum resolution. The availability of large samples of Z\rightarrow \mu \mu and J/\psi \rightarrow \mu \mu decays, and the minimisation of systematic uncertainties, allows the efficiencies of criteria for muon identification, primary vertex association, and isolation to be measured with an accuracy at the per-mille level in the bulk of the phase space, and up to the percent level in complex kinematic configurations. Excellent performance is achieved over a range of transverse momenta from 3 GeV to several hundred GeV, and across the full muon detector acceptance of |\eta |<2.7
Measurement of the ttÂŻttÂŻ production cross section in pp collisions at âs=13 TeV with the ATLAS detector
A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fbâ1 is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain b-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be 26+17â15 fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be 24+7â6 fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12.0 ± 2.4 fb
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