99 research outputs found
Setting up a quantitative SPECT imaging network for a European multi-centre dosimetry study of radioiodine treatment for thyroid cancer as part of the MEDIRAD project
Background: Differentiated thyroid cancer has been treated with radioiodine for almost 80 years, although controversial questions regarding radiation-related risks and the optimisation of treatment regimens remain unresolved. Multi-centre clinical studies are required to ensure recruitment of sufficient patients to achieve the statistical significance required to address these issues. Optimisation and standardisation of data acquisition and processing are necessary to ensure quantitative imaging and patient-specific dosimetry.
Material and methods: A European network of centres able to perform standardised quantitative imaging of radioiodine therapy of thyroid cancer patients was set-up within the EU consortium MEDIRAD. This network will support a concurrent series of clinical studies to determine accurately absorbed doses for thyroid cancer patients treated with radioiodine. Five SPECT(/CT) systems at four European centres were characterised with respect to their system volume sensitivity, recovery coefficients and dead time.
Results: System volume sensitivities of the Siemens Intevo systems (crystal thickness 3/8″) ranged from 62.1 to 73.5 cps/MBq. For a GE Discovery 670 (crystal thickness 5/8″) a system volume sensitivity of 92.2 cps/MBq was measured. Recovery coefficients measured on three Siemens Intevo systems show good agreement. For volumes larger than 10 ml, the maximum observed difference between recovery coefficients was found to be ± 0.02. Furthermore, dead-time coefficients measured on two Siemens Intevo systems agreed well with previously published dead-time values.
Conclusions: Results presented here provide additional support for the proposal to use global calibration parameters for cameras of the same make and model. This could potentially facilitate the extension of the imaging network for further dosimetry-based studies
Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, Svalbard
In this paper, we study the effects of basal friction, sub-aqueous
undercutting and glacier geometry on the calving process by combining six
different models in an offline-coupled workflow: a continuum–mechanical ice
flow model (Elmer/Ice), a climatic mass balance model, a simple subglacial
hydrology model, a plume model, an undercutting model and a discrete particle
model to investigate fracture dynamics (Helsinki Discrete Element Model,
HiDEM). We demonstrate the feasibility of reproducing the observed calving
retreat at the front of Kronebreen, a tidewater glacier in Svalbard, during a
melt season by using the output from the first five models as input to HiDEM.
Basal sliding and glacier motion are addressed using Elmer/Ice, while calving
is modelled by HiDEM. A hydrology model calculates subglacial drainage paths
and indicates two main outlets with different discharges. Depending on the
discharge, the plume model computes frontal melt rates, which are iteratively
projected to the actual front of the glacier at subglacial discharge
locations. This produces undercutting of different sizes, as melt is
concentrated close to the surface for high discharge and is more diffuse for
low discharge. By testing different configurations, we show that undercutting
plays a key role in glacier retreat and is necessary to reproduce observed
retreat in the vicinity of the discharge locations during the melting season.
Calving rates are also influenced by basal friction, through its effects on
near-terminus strain rates and ice velocity
Prophylactic cranial irradiation in small cell lung cancer: a systematic review of the literature with meta-analysis
PURPOSE: A systematic review of the literature was carried out to determine the role of prophylactic cranial irradiation (PCI) in small cell lung cancer (SCLC) . METHODS: To be eligible, full published trials needed to deal with SCLC and to have randomly assigned patients to receive PCI or not. Trials quality was assessed by two scores (Chalmers and ELCWP). RESULTS: Twelve randomised trials (1547 patients) were found to be eligible. Five evaluated the role of PCI in SCLC patients who had complete response (CR) after chemotherapy. Brain CT scan was done in the work-up in five studies and brain scintigraphy in six. Chalmers and ELCWP scores are well correlated (p < 0.001), with respective median scores of 32.6 and 38.8 %. This meta-analysis based on the available published data reveals a decrease of brain metastases incidence (hazard ratio (HR): 0.48; 95 % confidence interval (CI): 0.39 - 0.60) for all the studies and an improvement of survival (HR: 0.82; 95 % CI: 0.71 - 0.96) in patients in CR in favour of the PCI arm. Unfortunately, long-term neurotoxicity was not adequately described . CONCLUSIONS: PCI decreases brain metastases incidence and improves survival in CR SCLC patients but these effects were obtained in patients who had no systematic neuropsychological and brain imagery assessments. The long-term toxicity has not been prospectively evaluated. If PCI can be recommended in patients with SCLC and CR documented by a work-up including brain CT scan, data are lacking to generalise its use to any CR situations
Deregulation of Rab and Rab Effector Genes in Bladder Cancer
Growing evidence indicates that Rab GTPases, key regulators of intracellular transport in eukaryotic cells, play an important role in cancer. We analysed the deregulation at the transcriptional level of the genes encoding Rab proteins and Rab-interacting proteins in bladder cancer pathogenesis, distinguishing between the two main progression pathways so far identified in bladder cancer: the Ta pathway characterized by a high frequency of FGFR3 mutation and the carcinoma in situ pathway where no or infrequent FGFR3 mutations have been identified. A systematic literature search identified 61 genes encoding Rab proteins and 223 genes encoding Rab-interacting proteins. Transcriptomic data were obtained for normal urothelium samples and for two independent bladder cancer data sets corresponding to 152 and 75 tumors. Gene deregulation was analysed with the SAM (significant analysis of microarray) test or the binomial test. Overall, 30 genes were down-regulated, and 13 were up-regulated in the tumor samples. Five of these deregulated genes (LEPRE1, MICAL2, RAB23, STXBP1, SYTL1) were specifically deregulated in FGFR3-non-mutated muscle-invasive tumors. No gene encoding a Rab or Rab-interacting protein was found to be specifically deregulated in FGFR3-mutated tumors. Cluster analysis showed that the RAB27 gene cluster (comprising the genes encoding RAB27 and its interacting partners) was deregulated and that this deregulation was associated with both pathways of bladder cancer pathogenesis. Finally, we found that the expression of KIF20A and ZWINT was associated with that of proliferation markers and that the expression of MLPH, MYO5B, RAB11A, RAB11FIP1, RAB20 and SYTL2 was associated with that of urothelial cell differentiation markers. This systematic analysis of Rab and Rab effector gene deregulation in bladder cancer, taking relevant tumor subgroups into account, provides insight into the possible roles of Rab proteins and their effectors in bladder cancer pathogenesis. This approach is applicable to other group of genes and types of cancer
Role of Bcl-2 as a prognostic factor for survival in lung cancer: a systematic review of the literature with meta-analysis
The role of the anti-apoptotic protein Bcl-2 in lung cancer remains controversial. In order to clarify its impact on survival in small and non-small cell lung cancer (NSCLC), we performed a systematic review of the literature. Trials were selected for further analysis if they provided an independent assessment of Bcl-2 in lung cancer and reported analysis of survival data according to Bcl-2 status. To make it possible to aggregate survival results of the published studies, their methodology was assessed using a quality scale designed by the European Lung Cancer Working Party (including study design, laboratory methods and analysis). Of 28 studies, 11 identified Bcl-2 expression as a favourable prognostic factor and three linked it with poor prognosis; 14 trials were not significant. No differences in scoring measurement were detected between the studies, except that significantly higher scores were found in the trials with the largest sample sizes. Assessments of methodology and of laboratory technique were made independently of the conclusion of the trials. A total of 25 trials, comprising 3370 patients, provided sufficient information for the meta-analysis. The studies were categorised according to histology, disease stage and laboratory technique. The combined hazard ratio (HR) suggested that a positive Bcl-2 status has a favourable impact on survival: 0.70 (95% confidence interval 0.57-0.86) in seven studies on stages I-II NSCLC; 0.50 (0.39-0.65) in eight studies on surgically resected NSCLC; 0.91 (0.76-1.10) in six studies on any stage NSCLC; 0.57 (0.41-0.78) in five studies on squamous cell cancer; 0.75 (0.61-0.93) and 0.71 (0.61-0.83) respectively for five studies detecting Bcl-2 by immunohistochemistry with Ab clone 100 and for 13 studies assessing Bcl-2 with Ab clone 124; 0.92 (0.73-1.16) for four studies on small cell lung cancer; 1.26 (0.58-2.72) for three studies on neuroendocrine tumours. In NSCLC, Bcl-2 expression was associated with a better prognosis. The data on Bcl-2 expression in small cell lung cancer were insufficient to assess its prognostic value.Journal ArticleMeta-AnalysisResearch Support, Non-U.S. Gov'tReviewinfo:eu-repo/semantics/publishe
Allele-specific analysis of cell fusion-mediated pluripotent reprograming reveals distinct and predictive susceptibilities of human X-linked genes to reactivation
Estrogen-induced chromatin decondensation and nuclear re-organization linked to regional epigenetic regulation in breast cancer
BACKGROUND: Epigenetic changes are being increasingly recognized as a prominent feature of cancer. This occurs not only at individual genes, but also over larger chromosomal domains. To investigate this, we set out to identify large chromosomal domains of epigenetic dysregulation in breast cancers. RESULTS: We identify large regions of coordinate down-regulation of gene expression, and other regions of coordinate activation, in breast cancers and show that these regions are linked to tumor subtype. In particular we show that a group of coordinately regulated regions are expressed in luminal, estrogen-receptor positive breast tumors and cell lines. For one of these regions of coordinate gene activation, we show that regional epigenetic regulation is accompanied by visible unfolding of large-scale chromatin structure and a repositioning of the region within the nucleus. In MCF7 cells, we show that this depends on the presence of estrogen. CONCLUSIONS: Our data suggest that the liganded estrogen receptor is linked to long-range changes in higher-order chromatin organization and epigenetic dysregulation in cancer. This may suggest that as well as drugs targeting histone modifications, it will be valuable to investigate the inhibition of protein complexes involved in chromatin folding in cancer cells. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13059-015-0719-9) contains supplementary material, which is available to authorized users
Temporal changes in the epidemiology, management, and outcome from acute respiratory distress syndrome in European intensive care units: a comparison of two large cohorts
Background: Mortality rates for patients with ARDS remain high. We assessed temporal changes in the epidemiology and management of ARDS patients requiring invasive mechanical ventilation in European ICUs. We also investigated the association between ventilatory settings and outcome in these patients. Methods: This was a post hoc analysis of two cohorts of adult ICU patients admitted between May 1–15, 2002 (SOAP study, n = 3147), and May 8–18, 2012 (ICON audit, n = 4601 admitted to ICUs in the same 24 countries as the SOAP study). ARDS was defined retrospectively using the Berlin definitions. Values of tidal volume, PEEP, plateau pressure, and FiO2 corresponding to the most abnormal value of arterial PO2 were recorded prospectively every 24 h. In both studies, patients were followed for outcome until death, hospital discharge or for 60 days. Results: The frequency of ARDS requiring mechanical ventilation during the ICU stay was similar in SOAP and ICON (327[10.4%] vs. 494[10.7%], p = 0.793). The diagnosis of ARDS was established at a median of 3 (IQ: 1–7) days after admission in SOAP and 2 (1–6) days in ICON. Within 24 h of diagnosis, ARDS was mild in 244 (29.7%), moderate in 388 (47.3%), and severe in 189 (23.0%) patients. In patients with ARDS, tidal volumes were lower in the later (ICON) than in the earlier (SOAP) cohort. Plateau and driving pressures were also lower in ICON than in SOAP. ICU (134[41.1%] vs 179[36.9%]) and hospital (151[46.2%] vs 212[44.4%]) mortality rates in patients with ARDS were similar in SOAP and ICON. High plateau pressure (> 29 cmH2O) and driving pressure (> 14 cmH2O) on the first day of mechanical ventilation but not tidal volume (> 8 ml/kg predicted body weight [PBW]) were independently associated with a higher risk of in-hospital death. Conclusion: The frequency of and outcome from ARDS remained relatively stable between 2002 and 2012. Plateau pressure > 29 cmH2O and driving pressure > 14 cmH2O on the first day of mechanical ventilation but not tidal volume > 8 ml/kg PBW were independently associated with a higher risk of death. These data highlight the continued burden of ARDS and provide hypothesis-generating data for the design of future studies
Topological organization of multichromosomal regions by the long intergenic noncoding RNA Firre
RNA, including long noncoding RNA (lncRNA), is known to be an abundant and important structural component of the nuclear matrix. However, the molecular identities, functional roles and localization dynamics of lncRNAs that influence nuclear architecture remain poorly understood. Here, we describe one lncRNA, Firre, that interacts with the nuclear-matrix factor hnRNPU through a 156-bp repeating sequence and localizes across an ~5-Mb domain on the X chromosome. We further observed Firre localization across five distinct trans-chromosomal loci, which reside in spatial proximity to the Firre genomic locus on the X chromosome. Both genetic deletion of the Firre locus and knockdown of hnRNPU resulted in loss of colocalization of these trans-chromosomal interacting loci. Thus, our data suggest a model in which lncRNAs such as Firre can interface with and modulate nuclear architecture across chromosomes
When is an endoscopy of the upper digestive tract required in a patient undergoing or about to undergo non steroidal anti-inflammatory (NSAI) treatment ?
Les indications de l'endoscopie haute chez un patient qui doit être mis sous traitement AINS ou qui est sous traitement sont encore discutées. L'utilité d'une exploration doit être appréciée en fonction des conséquences que peuvent avoir les résultats sur l'attitude thérapeutique. Il n'y a pas de relation entre l'existence des symptômes et la sévérité des lésions gastroduodénales. Avant d'entreprendre un traitement aux AINS, l'endoscopie n'est pas systématique. Chez un patient symptomatique et sans antécédent digestif, la fibroscopie haute n'est pas utile avant un traitement AINS en cas de douleurs épigastriques de type reflux ou de type moteur, en cas de symptomatologie de type ulcéreux ou indéterminée. on peut soit opter pour une fibroscopie préalable, soit pour une co-prescription maximale de principe. Chez les patients ayant des antécédents digestifs hauts connus explorés, l'intérêt ou l'utilité d'une endoscopie préalable, est fonction de la nature de l'affection préexistante. La notion d'éradication d'Helicobacter pylori ne modifie pas l'indication d'une endoscopie digestive avant traitement AINS. Chez les patients sous AINS, l'endoscopie est indiquée en cas de symptômes sévères et a fortiori de complication hémorragique et d'anémie ou lorsque les symptômes ne disparaissent pas rapidement après l'arrêt des AINS. Le contrôle endoscopique de la cicatrisation est recommandé surtout lorsque le traitement AINS doit être poursuivi. En cas d'arrêt du traitement AINS, le contrôle de la cicatrisation peut être recommandé dans le cas d'un cas d'ulcère gastrique, d'ulcère duodénal compliqué ou si le patient n'est pas asymptomatique. Les indications de l'endoscopie haute chez les patients sous traitement ou devant prendre un traitement AINS NS sont relativement limitées et doivent être encore évaluées
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