The use of premature chromosome condensation to study in interphase cells the influence of environmental factors on human genetic material

Nowadays, there is a constantly increasing concern regarding the mutagenic and carcinogenic potential of a variety of harmful environmental factors to which humans are exposed in their natural and anthropogenic environment. These factors exert their hazardous potential in humans' personal (diet, smoking, pharmaceuticals, cosmetics) and occupational environment that constitute part of the anthropogenic environment. It is well known that genetic damage due to these factors has dramatic implications for human health. Since most of the environmental genotoxic factors induce arrest or delay in cell cycle progression, the conventional analysis of chromosomes at metaphase may underestimate their genotoxic potential. Premature Chromosome Condensation (PCC) induced either by means of cell fusion or specific chemicals, enables the microscopic visualization of interphase chromosomes whose morphology depends on the cell cycle stage, as well as the analysis of structural and numerical aberrations at the G1 and G2 phases of the cell cycle. The PCC has been successfully used in problems involving cell cycle analysis, diagnosis and prognosis of human leukaemia, assessment of interphase chromosome malformations resulting from exposure to radiation or chemicals, as well as elucidation of the mechanisms underlying the conversion of DNA damage into chromosomal damage. In this report, particular emphasis is given to the advantages of the PCC methodology used as an alternative to conventional metaphase analysis in answering questions in the fields of radiobiology, biological dosimetry, toxicogenetics, clinical cytogenetics and experimental therapeutics

Systematic review and meta-analysis of the value of initial biomarkers in predicting adverse outcome in febrile neutropenic episodes in children and young people with cancer

Background: Febrile neutropenia is a frequently occurring and occasionally life-threatening complication of treatment for childhood cancer. Many biomarkers have been proposed as predictors of adverse events. We aimed to undertake a systematic review and meta-analysis to summarize evidence on the discriminatory ability of initial serum biomarkers of febrile neutropenic episodes in children and young people. Methods: This review was conducted in accordance with the Center for Reviews and Dissemination Methods, using three random effects models to undertake meta-analysis. It was registered with the HTA Registry of systematic reviews, CRD32009100485. Results: We found that 25 studies exploring 14 different biomarkers were assessed in 3,585 episodes of febrile neutropenia. C-reactive protein (CRP), pro-calcitonin (PCT), and interleukin-6 (IL6) were subject to quantitative meta-analysis, and revealed huge inconsistencies and heterogeneity in the studies included in this review. Only CRP has been evaluated in assessing its value over the predictive value of simple clinical decision rules. Conclusions: The limited data available describing the predictive value of biomarkers in the setting of pediatric febrile neutropenia mean firm conclusions cannot yet be reached, although the use of IL6, IL8 and procalcitonin warrant further study

Realising the European network of biodosimetry: RENEB-status quo

Creating a sustainable network in biological and retrospective dosimetry that involves a large number of experienced laboratories throughout the European Union (EU) will significantly improve the accident and emergency response capabilities in case of a large-scale radiological emergency. A well-organised cooperative action involving EU laboratories will offer the best chance for fast and trustworthy dose assessments that are urgently needed in an emergency situation. To this end, the EC supports the establishment of a European network in biological dosimetry (RENEB). The RENEB project started in January 2012 involving cooperation of 23 organisations from 16 European countries. The purpose of RENEB is to increase the biodosimetry capacities in case of large-scale radiological emergency scenarios. The progress of the project since its inception is presented, comprising the consolidation process of the network with its operational platform, intercomparison exercises, training activities, proceedings in quality assurance and horizon scanning for new methods and partners. Additionally, the benefit of the network for the radiation research community as a whole is addressed

BCL6-mediated repression of p53 is critical for leukemia stem cell survival in chronic myeloid leukemia

Chronic myeloid leukemia (CML) is induced by the oncogenic BCR-ABL1 tyrosine kinase and can be effectively treated for many years with tyrosine kinase inhibitors (TKIs). However, unless CML patients receive life-long TKI treatment, leukemia will eventually recur; this is attributed to the failure of TKI treatment to eradicate leukemia-initiating cells (LICs). Recent work demonstrated that FoxO factors are critical for maintenance of CML-initiating cells; however, the mechanism of FoxO-dependent leukemia initiation remained elusive. Here, we identified the BCL6 protooncogene as a critical effector downstream of FoxO in self-renewal signaling of CML-initiating cells. BCL6 represses Arf and p53 in CML cells and is required for colony formation and initiation of leukemia. Importantly, peptide inhibition of BCL6 in human CML cells compromises colony formation and leukemia initiation in transplant recipients and selectively eradicates CD34+ CD38− LICs in patient-derived CML samples. These findings suggest that pharmacological inhibition of BCL6 may represent a novel strategy to eradicate LICs in CML. Clinical validation of this concept could limit the duration of TKI treatment in CML patients, which is currently life-long, and substantially decrease the risk of blast crisis transformation

Immunological aspects in chronic lymphocytic leukemia (CLL) development

Chronic lymphocytic leukemia (CLL) is unique among B cell malignancies in that the malignant clones can be featured either somatically mutated or unmutated IGVH genes. CLL cells that express unmutated immunoglobulin variable domains likely underwent final development prior to their entry into the germinal center, whereas those that express mutated variable domains likely transited through the germinal center and then underwent final development. Regardless, the cellular origin of CLL remains unknown. The aim of this review is to summarize immunological aspects involved in this process and to provide insights about the complex biology and pathogenesis of this disease. We propose a mechanistic hypothesis to explain the origin of B-CLL clones into our current picture of normal B cell development. In particular, we suggest that unmutated CLL arises from normal B cells with self-reactivity for apoptotic bodies that have undergone receptor editing, CD5 expression, and anergic processes in the bone marrow. Similarly, mutated CLL would arise from cells that, while acquiring self-reactivity for autoantigens—including apoptotic bodies—in germinal centers, are also still subject to tolerization mechanisms, including receptor editing and anergy. We believe that CLL is a proliferation of B lymphocytes selected during clonal expansion through multiple encounters with (auto)antigens, despite the fact that they differ in their state of activation and maturation. Autoantigens and microbial pathogens activate BCR signaling and promote tolerogenic mechanisms such as receptor editing/revision, anergy, CD5+ expression, and somatic hypermutation in CLL B cells. The result of these tolerogenic mechanisms is the survival of CLL B cell clones with similar surface markers and homogeneous gene expression signatures. We suggest that both immunophenotypic surface markers and homogenous gene expression might represent the evidence of several attempts to re-educate self-reactive B cells

Suppression of BCL6 Function by HDAC Inhibitor Mediated Acetylation and Chromatin Modification Enhances BET Inhibitor Effects in B-cell Lymphoma Cells

Multiple genetic aberrations in the regulation of BCL6, including in acetyltransferase genes, occur in clinically aggressive B-cell lymphomas and lead to higher expression levels and activity of this transcriptional repressor. BCL6 is, therefore, an attractive target for therapy in aggressive lymphomas. In this study romidepsin, a potent histone deacetylase inhibitor (HDACi), induced apoptosis and cell cycle arrest in Burkitt and diffuse large B-cell lymphoma cell lines, which are model cells for studying the mechanism of action of BCL6. Romidepsin caused BCL6 acetylation at early timepoints inhibiting its function, while at later timepoints BCL6 expression was reduced and target gene expression increased due to chromatin modification. MYC contributes to poor prognosis in aggressive lymphoma. MYC function is reduced by inhibition of chromatin readers of the bromodomain and extra-terminal repeat (BET) family, which includes BRD4. The novel combination of romidepsin and JQ1, a BRD4 inhibitor was investigated and showed synergy. Collectively we suggest that the combination of HDACi and BRD4i should be pursued in further pre-clinical testing.Funding: The work was supported by grants SAF2014-53526-R and SAF2017-88026-R from MINECO, Spanish Government, to M.D.D. and J.L. (partially funded by FEDER program from European Union). M.G.C. was recipient of a “Marcos Fernández” fellowship from Leukemia and Lymphoma foundation. L.G.G. was recipient of a FPI fellowship from Spanish Government

Setting characteristics of vinyl-polysiloxane interocclusal recording materials

Objectives: To investigate the elemental and molecular composition, curing efficiency, setting shrinkage strain and hardness of vinyl-polysiloxane interocclusal recording materials. Methods: The materials tested were Blu-Mousse Classic/BMC, Exabite II NDS/EXB, Futar Scan/FTS, O-Bite/OBT, Occlufast Rock/OFR, R-Si-Line Metalbite/RMB and Stone Bite/STB. Composition was examined by SEM/EDX and micro-ATR FTIR. Curing efficiency (n: 7) was evaluated by micro-ATR FTIR on unset materials and following 3, 5, and 10 min after mixing. Setting shrinkage strain (%S, n: 7) was evaluated by the bonded-disk method as a function of time up to 10 min after mixing and Shore-D hardness measurements (n: 7) were performed at setting time and after 72 h storage at room temperature. Statistical analysis was performed by one-way ANOVA and paired t-tests (a: 0.05). Results: All materials were particle-filled vinyl-polysiloxane composites with different elemental composition. C, O and Si were found at highest concentration in all products, whereas Al, Na, Mg, Ti and Ca were additionally detected. Curing efficiency measurements ranked the products in three statistically homogeneous groups (OFR, EXB, OBT > FTS, RMB > BMC, STB) at all time intervals, except OFR which at 5 and 10 min was ranked in the second group. In all products, a statistically significant increase in %S max values was found in comparison with %S at setting time. Strain saturation was reached by all materials at different time intervals, except from BMC and OBT. Hardness differences were detected among materials for the same time interval and between time intervals per material. Significance: Differences among materials were detected regarding the properties tested, which may imply variations in their clinical performance. © 2012 Academy of Dental Materials. All rights reserved

Building a Social Platform Using FLOSS to Support Collaborative Communities: The ReWeee Case Study

Part 6: OSS ReusabilityInternational audienceIn this paper we present the development of a collaborative community using exclusively open source software. After the definition of the functional requirements of the project, we focus on finding specific software components to satisfy these requirements. The intention was to minimize the development effort and labor, relying on open source software. As a result, the platform was developed writing less than 10% of the required code and reusing more than 20 software components, not counting the software dependencies. The new components developed form our contribution to the community