804 research outputs found
Incidental findings of mass lesions on neuroimages in children
Increasing use of neuroimaging in children has led to more incidental findings of CNS mass lesions, the management of which is uncertain. The authors' aims in this study are to describe these mass lesions and their evolution, as well as to discuss the management options and determine the prevalence of incidental CNS mass lesions at their pediatric clinic. A retrospective study was undertaken in children with primary CNS tumors who were younger than 18 years old and were admitted to the University Children's Hospital of Zurich, Switzerland, between January 1995 and December 2010. In 19 (5.7%) of 335 patients with newly diagnosed CNS tumors, the diagnosis of a CNS mass lesion was an incidental finding. Reasons for obtaining neuroimages in these 19 patients were head trauma (in 6 patients); research protocols (in 3); nasal/orbital malformations (in 2); endocrinological and psychiatric evaluations (in 2); and vertebral bone anomaly without neurological signs, absence seizures, congenital ataxia, recurrent vomiting, developmental delay, and "check-up" at the explicit request of the parents (in 1 patient each). Seven patients underwent immediate surgery for low-grade glioma (4 patients) and craniopharyngioma, ependymoma, and choroid plexus papilloma (1 patient each); and 12 were treated conservatively or were observed. Ten of 12 conservatively treated patients remained stable (median follow-up time 1.8 years) and the other 2 underwent delayed surgery because of tumor progression (medulloblastoma in one patient and fibrillary astrocytoma in the other). Clinicians are increasingly challenged by the discovery of incidental CNS mass lesions. A subgroup of such lesions (with typical imaging patterns such as tectal glioma and dysembryoplastic neuroepithelial tumor) can be monitored conservatively, clinically, and radiographically. Future prospective studies are needed to define optimal management strategies based on larger collections of natural histories, as well as to assess the true prevalence of incidental CNS mass lesions
The possibilities and prospects of obtaining high-resolution information (below 30 Å) on biological material using the electron microscope: Some comments and reports inspired by an EMBO workshop held at Gais, Switzerland, October 1973
Commercially available electron microscopes routinely provide resolution of some 2-4 Å, as determined on the spacing of crystalline lattices of certain stable, small-molecular substances. On biological material either macromolecules or macromolecular assemblies— ‘biologically significant' details below some 20 Å have hitherto not been observed.we consider as ‘biologically significant' those structural details observed or contained in electronmicrographs which are consistent with, or confirmed by, other data obtained from biochemical or functional experiments or by other physical methods (optical, magnetic, electric
Gastric emptying after overnight fasting and clear fluid intake: a prospective investigation using serial magnetic resonance imaging in healthy children†
Background Current guidelines recommend preoperative fasting of 2 h for clear fluids, which is often exceeded in routine clinical practice. Existing data on residual gastric volumes in children do not consider fluid intake within <2 h and rely on the aspiration of gastric contents via a gastric tube. This study evaluated the emptying of clear fluids from the stomach using magnetic resonance imaging (MRI). Methods Healthy volunteers aged 6-14 years were asked to fast overnight. MRI scans to assess gastric volumes were obtained before and immediately after drinking 7 ml kg−1 of diluted raspberry syrup and then every 30 min up to 120 min. Volumes were determined by a blinded investigator and indexed gastric fluid/air volumes (GFVw/GAVw) and half-life (t1/2) of GFVw course after clear fluid intake were calculated. Results Sixteen children, median age 9.2 (range 6.4-12.8) years, were investigated. Median (range) GFVw was 0.62 (0.15-0.97) ml kg−1 before and 6.68 (4.77-7.78) ml kg−1 immediately after fluid intake, and 2.92 (0.43-5.04), 1.27 (0.28-3.62), 0.42 (0.07-2.49), and 0.32 (0.04-1.13) ml kg−1 30, 60, 90, and 120 min thereafter. Median GFVw declined exponentially (t1/2=26.1 min). Median individual t1/2 was 23.6 (range 17.9-47.8) min. GAVw showed considerable intra- and inter-individual variation. Conclusions In healthy school children, gastric emptying after ingestion of clear fluid occurs with a median half-life time of <30 min but with considerable inter-individual variatio
Effect of different quantities of a sugared clear fluid on gastric emptying and residual volume in children: a crossover study using magnetic resonance imaging
Background Gastric emptying in the first 2 h after 7 ml kg−1 of sugared clear fluid has recently been investigated in healthy children using magnetic resonance imaging (MRI). This study aims to compare gastric volume and emptying half-life during 1 h after 3 or 7 ml kg−1 sugared clear fluid intake. Methods Fourteen healthy volunteer children aged 11.1 (8.2-12.5) yr were investigated prospectively after administration of 3 and 7 ml kg−1 diluted raspberry syrup in a randomized order, after overnight fasting (baseline). Gastric content volume (GCVw) was assessed with a 1.5 Tesla MRI scanner in a blinded fashion. Data are presented as median (range) and compared using the Wilcoxon test. Results Baseline GCVw was 0.39 (0.04-1.00) and 0.34 (0.07-0.75) before intake of 3 and 7 ml kg−1 syrup, respectively (P=0.93). GCVw was 0.45 (0.04-1.55)/1.33 (0.30-2.60) ml kg−1 60 min after ingestion of 3/7 ml kg−1 syrup (P=0.002). Thus GCVw had declined to baseline after 3 ml kg−1 (P=0.39) but not after 7 ml kg−1 (P=0.001) within 60 min. T1/2 was 20 (10-62)/27 (13-43) min (P=0.73) after 3/7 ml kg−1. Conclusion In healthy volunteer children, residual GCVw 1 h after intake of 3 ml kg−1 syrup is significantly smaller than that after 7 ml kg−1 and within the range of baselin
The Role of Dysregulated Glucose Metabolism in Epithelial Ovarian Cancer
Epithelial ovarian cancer (EOC) is the most lethal gynecologic cancer and also one of the most poorly understood. Other health issues that are affecting women with increasing frequency are obesity and diabetes, which are associated with dysglycemia and increased blood glucose. The Warburg Effect describes the ability of fast-growing cancer cells to preferentially metabolize glucose via anaerobic glycolysis rather than oxidative phosphorylation. Recent epidemiological studies have suggested a role for hyperglycemia in the pathogenesis of a number of cancers. If hyperglycemia contributes to tumour growth and progression, then it is intuitive that antihyperglycemic drugs may also have an important antitumour role. Preliminary reports suggest that these drugs not only reduce available plasma glucose, but also have direct effects on cancer cell viability through modification of molecular energy-sensing pathways. This review investigates the effect that hyperglycemia may have on EOC and the potential of antihyperglycemic drugs as therapeutic adjuncts
SOFIAS – Herramienta para el análisis de ciclo de vida y la calificación ambiental de edificios
This paper describes the development process of a new software tool, called SOFIAS (Software for a Sustainable Architecture), funded by the Spanish Ministry of Economy and Competitivenes. Following CEN/TC 350 standard on environmental assessment of buildings, the tool aims at assisting building professionals on reducing the life-cycle environmental impact through the design of new buildings and the refurbishment of existing ones. In addition, SOFIAS provides a rating system based on the Life Cycle Assessment (LCA) methodology. This paper explains the innovative aspects of this software, the working methodology and the different type of results that can be obtained using SOFIAS.SOFIAS (Ref. number IPT-2011-0948-380000) project co financed by the Spanish Ministry of Economy and Competitiveness
Is the kinetoplast DNA a percolating network of linked rings at its critical point?
In this work we present a computational study of the Kinetoplast genome,
modelled as a large number of semiflexible unknotted loops, which are allowed
to link with each other. As the DNA density increases, the systems shows a
percolation transition between a gas of unlinked rings and a network of linked
loops which spans the whole system. Close to the percolation transition, we
find that the mean valency of the network, i.e. the average number of loops
which are linked to any one loop, is around 3 as found experimentally for the
Kinetoplast DNA. Even more importantly, by simulating the digestion of the
network by a restriction enzyme, we show that the distribution of oligomers,
i.e. structures formed by a few loops which remain linked after digestion,
quantitatively matches experimental data obtained from gel electrophoresis,
provided that the density is, once again, close to the percolation transition.
With respect to previous work, our analysis builds on a reduced number of
assumptions, yet can still fully explain the experimental data. Our findings
suggest that the Kinetoplast DNA can be viewed as a network of linked loops
positioned very close to the percolation transition, and we discuss the
possible biological implications of this remarkable fact.Comment: 13p, 5f, merged S
Multicentre reference values for cardiac magnetic resonance imaging derived ventricular size and function for children aged 0-18 years
AIMS: Cardiovascular magnetic resonance (CMR) imaging is an important tool in the assessment of paediatric cardiac disease. Reported reference values of ventricular volumes and masses in the paediatric population are based on small cohorts and several methodologic differences between studies exist. We sought to create steady-state free precession (SSFP) CMR reference values for biventricular volumes and mass by combining data of previously published studies and re-analysing these data in a standardized manner. METHODS AND RESULTS: A total of 141 healthy children (68 boys) from three European centres underwent cine-SSFP CMR imaging. Cardiac structures were manually contoured for end-diastolic and end-systolic phases in the short-axis orientation according to current standardized CMR post-processing guidelines. Volumes and masses were derived from these contours. Age-related reference curves were constructed using the lambda mu sigma method. Median age was 12.7 years (range 0.6-18.5). We report biventricular volumes and masses, unindexed and indexed for body surface area, stratified by age groups. In general, boys had approximately 15% higher biventricular volumes and masses compared with girls. Only in children aged <6 years old no gender differences could be observed. Left ventricle ejection fraction was slightly higher in boys in this study population (median 67% vs. 65%, P = 0.016). Age-related reference curves showed non-linear relations between age and cardiac parameters. CONCLUSION: We report volumetric SSFP CMR imaging reference values for children aged 0-18 years old in a relatively large multi-centre cohort. These references can be used in the follow-up of paedi
LigASite—a database of biologically relevant binding sites in proteins with known apo-structures
Better characterization of binding sites in proteins and the ability to accurately predict their location and energetic properties are major challenges which, if addressed, would have many valuable practical applications. Unfortunately, reliable benchmark datasets of binding sites in proteins are still sorely lacking. Here, we present LigASite (‘LIGand Attachment SITE’), a gold-standard dataset of binding sites in 550 proteins of known structures. LigASite consists exclusively of biologically relevant binding sites in proteins for which at least one apo- and one holo-structure are available. In defining the binding sites for each protein, information from all holo-structures is combined, considering in each case the quaternary structure defined by the PQS server. LigASite is built using simple criteria and is automatically updated as new structures become available in the PDB, thereby guaranteeing optimal data coverage over time. Both a redundant and a culled non-redundant version of the dataset is available at http://www.scmbb.ulb.ac.be/Users/benoit/LigASite. The website interface allows users to search the dataset by PDB identifiers, ligand identifiers, protein names or sequence, and to look for structural matches as defined by the CATH homologous superfamilies. The datasets can be downloaded from the website as Schema-validated XML files or comma-separated flat files
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