Intracystic Therapies for Cystic Craniopharyngioma in Childhood

Introduction: Craniopharyngioma of childhood are commonly cystic in nature. An intracystic catheter insertion and subsequent instillation of substances inducing cyst shrinkage seems a beneficial strategy avoiding additional morbidity in a highly vulnerable brain location. Methods: A systematic review of the medical literature was performed to identify potentially relevant, all languages articles using Ovid MEDLINE and EMBASE from inception to July 2011 and Cochrane Central Register of Controlled Trials to third quarter 2011. All references were examined for relevancy. Results: Of 142 unique references, 71 referred to substances used for intracystic craniopharyngioma treatment. General aspects of intracystic catheter insertion as well as response rates, risks, and outcomes of children treated with intracystic radioisotopes, bleomycin, and interferon (IFN) are critically reviewed and an outline for potential future endeavors provided. Conclusion: IFN seems currently the intracystic substance with the best benefit risk ratio. The authors advocate for consensus on prospective data collection and standardized intracystic treatment strategies to allow reliable comparisons and herewith optimize treatment and outcome

Evolution de la structure VLBI des sources de l'ICRF : lien entre astrométrie et astrophysique

Active Galactic Nuclei (AGN) are located in the center of extremely distant and bright galaxies. Their luminosity comes from the interaction between a super-massive central blackhole and an accretion disk, producing a relativistic collimated jet of matter. Thanks to the extremely high resolution achieved by Very Long Base line Interferometry (VLBI), the jet structure may be studied in detail, while the astrometric position of the AGN is determined with ahigh accuracy. Because of their location at cosmological distances, no proper motions are detected for those objects, making them ideal fiducial points for building highly-precise celestial reference frames.Instabilities up to a few hundreds of micro arc seconds are yet often observed in astrometricpositions on time scales from months to years. This is generally thought to be caused by theevolution of source structure. The study presented here investigates the correlation between the two phenomena on a statistical basis. Based on regular VLBI observations conducted between1994 and 2003, astrometric position variations and source structure evolution are compared fora sample of 68 AGN over a period of 10 years. The results indicate that a correlation between the two phenomena does exist but it is not as strong as expected. Additionally, a simulation of the effects caused by the precession of the accretion disc and the potential presence of abinary black hole in the center of the AGN is presented. Applied to the source 1308+326, the simulation shows that the magnitude of the effects is consistent with the oscillations of the jet trajectory observed on VLBI scale.Les Noyaux Actifs de Galaxies (AGN) se situent au centre de galaxies extrêmement lointainesdont la luminosité provient de l’interaction d’un trou noir central supermassif et d’undisque d’accrétion. Il en résulte l’éjection à des vitesses relativistes de jets de matière collimatés.L’interférométrie à très longue base (VLBI) permet, grâce aux très grandes résolutionsatteintes, d’observer finement la structure de ces jets et de déterminer très précisément laposition astrométrique des objets. En raison de leur distance, les AGN ne présentent pas demouvements propres, ce qui les rend idéaux pour la construction de systèmes de référenceultra-précis et très stables.Des instabilités en position de quelques centaines de microsecondes d’arc, généralementimputées aux variations de la structure des jets, sont toutefois souvent observées sur des échellesde temps de quelques mois à quelques années. Le travail présenté ici étudie le lien entre les deuxphénomènes de façon statistique. Sur la base d’observations VLBI régulières conduites entre1994 et 2003, nous comparons l’évolution de la position astrométrique et de la structure des jetspour un échantillon de 68 AGN sur une période de 10 ans. Les résultats de l’étude indiquent quela corrélation entre les deux phénomènes existe mais n’est pas aussi forte qu’attendue. Le travailest complété par une simulation des effets causés sur la trajectoire des jets par la précessiondu disque d’accrétion ainsi que par la présence d’un système binaire de trous noirs. Appliquéeau cas de la source 1308+326, l’étude montre que l’amplitude de ces effets est compatible avecles oscillations de la trajectoire observées en VLBI

Report for 2012 from the Bordeaux IVS Analysis Center

This report summarizes the activities of the Bordeaux IVS Analysis Center during the year 2012. The work focused on (i) regular analysis of the IVS-R1 and IVS-R4 sessions with the GINS software package; (ii) systematic VLBI imaging of the RDV sessions and calculation of the corresponding source structure index and compactness values; (iii) investigation of the correlation between astrometric position instabilities and source structure variations; and (iv) continuation of our VLBI observational program to identify optically-bright radio sources suitable for the link with the future Gaia frame. Also of importance is the 11th European VLBI Network Symposium, which we organized last October in Bordeaux and which drew much attention from the European and International VLBI communities

Early advice on managing children with cancer during the COVID-19 pandemic and a call for sharing experiences

We are living very difficult times. The pandemic caused by SARS‐CoV‐2 (COVID‐19) is rapidly affecting the delivery of care for children with cancer around the world. We have written this commentary to facilitate the dissemination of helpful information and useful links, and to place in perspective what we do and do not know about the COVID‐19 pandemic and its impact in the practice of paediatric oncology. Generally speaking, the impact that this virus may have on the paediatric population, and the management of children with cancer, remains unclear and poorly documented. The next two sections outline what has been published or communicated via academic websites, both in children and adults with cancer

Childhood medulloblastoma

Medulloblastoma is the most common malignant brain tumour in children and is a major cause of mortality and morbidity, particularly in low- and middle-income countries. It has been risk-stratified on the basis of clinical (age, metastasis and extent of resection) and histological subtypes (classic, desmoplastic and anaplastic). However, recently medulloblastoma has been sub-grouped by using a variety of different genomic approaches, such as gene expression profiling, micro-ribonucleic acid profiling and methylation array into 4 groups, namely Wingless, Sonic hedgehog, Group 3 and Group 4. This new sub-grouping has important therapeutic and prognostic implications. After acute leukaemia, brain tumour is the second most common malignancy in the paediatric age group. The improvement in outcome of acute lymphoblastic leukaemia in low- and middle-income countries reflects the relative simplicity of diagnostic procedures and management. Unlike leukaemia, the management of brain tumours requires a complex multidisciplinary approach, including neuro-radiologists, neurosurgeons with a paediatric expertise, neuropathologists, radiation oncologists and neuro-oncologists. In addition, the equipment required for the diagnosis (magnetic resonance imaging scan, histological, molecular and genetic techniques) and the management (operating room, radiation facilities) is a limiting factor in countries with limited resources. In Pakistan, there are very few centres able to treat children with brain tumours. The current literature review was planned to provide an update on the management of this tumour

Tribochemistry of phosphorus additives: Experiments and first-principles calculations

Organophosphorus compounds are common additives included in liquid lubricants for many applications, in particular automotive applications. Typically, organic phosphites function as friction-modifiers whereas phosphates as anti-wear additives. While the antiwear action of phosphates is now well understood, the mechanism by which phosphites reduce friction is still not clear. Here we study the tribochemistry of both phosphites and phosphates using gas phase lubrication (GPL) and elucidate the microscopic mechanisms that lead to the better frictional properties of phosphites. In particular, by in situ spectroscopic analysis we show that the friction reduction is connected to the presence of iron phosphide, which is formed by tribochemical reactions involving phosphites. The functionality of elemental phosphorus in reducing the friction of iron-based interfaces is elucidated by first principle calculations. In particular, we show that the work of separation and shear strength of iron dramatically decrease by increasing the phosphorus concentration at the interface. These results suggest that the functionality of phosphites as friction modifiers may be related to the amount of elemental phosphorus that they can release at the tribological interface

Medulloblastoma has a global impact on health related quality of life: Findings from an international cohort.

BackgroundUnderstanding the global impact of medulloblastoma on health related quality of life (HRQL) is critical to characterizing the broad impact of this disease and realizing the benefits of modern treatments. We evaluated HRQL in an international cohort of pediatric medulloblastoma patients.MethodsSeventy-six patients were selected from 10 sites across North America, Europe, and Asia, who participated in the Medulloblastoma Advanced Genomics International Consortium (MAGIC). The Health Utilities Index (HUI) was administered to patients and/or parents at each site. Responses were used to determine overall HRQL and attributes (ie specific subdomains). The impact of various demographic and medical variables on HRQL was considered-including molecular subgroup.ResultsThe majority of patients reported having moderate or severe overall burden of morbidity for both the HUI2 and HUI3 (HUI2 = 60%; HUI3 = 72.1%) when proxy-assessed. Self-care in the HUI2 was rated as higher (ie better outcome) for patients from Western versus Eastern sites, P = .02. Patients with nonmetastatic status had higher values (ie better outcomes) for the HUI3 hearing, HUI3 pain, and HUI2 pain, all P < .05. Patients treated with a gross total resection also had better outcomes for the HUI3 hearing (P = .04). However, those who underwent a gross total resection reported having worse outcomes on the HUI3 vision (P = .02). No differences in HRQL were evident as a function of subgroup.ConclusionsBy examining an international sample of survivors, we characterized the worldwide impact of medulloblastoma. This is a critical first step in developing global standards for evaluating long-term outcomes