Traitements nématicides et peuplement de nématodes parasites de la canne à sucre au Burkina Faso : 1. Repousses

International audienceNematicides and nematode community parasitic on sugarcane in Burkina Faso. 1. Ratoon cane Triadic analysis of three ways tables provides a means for studying the effect of nematicide treatments applied on sugarcane ratoons upon nematodes populations dynamics, by taking into account the between-plots variability of nematodes numbers. Only fumigation applied before planting has markedly reduced the size of the community. The treatments applied in ratoons next years has only a moderate effect upon nematode multiplication. For al! the treatments that we have compared, the size of the community tends to increase from ratoon to ratoon. Oxamyl, carbofuran and aldicarb, employed in ratoon, modify the balance between endoparasitic populations; their application is followed by the formation of a community dominated by Meloidogyne and Pratylenchus at the end of the crop. However, on the control, after the second ratoon the populations of Paratylenchus, Hoplo/aimus and Heterodera become more important than the populations of Meloidogyne and Pratylenchus. Helicotylenchus is more influenced by seasonal fluctuations than by treatments.L'analyse triadique de tableaux multiples a permis d'extraire les contraintes imposées à la dynamique des populations de nématodes par l'application de traitements nématicides sur des repousses de canne à sucre, sans éliminer la variabilité interparcellaire. Seule la fumigation effectuée avant la plantation a provoqué une baisse importante du volume du peuplement. Les traitements appliqués les années suivantes en repousse n'affectent que modérément la multiplication des nématodes. Dans toutes les séquences de traitements comparées, le volume du peuplement a tendance à s'accroître au fil des repousses. Oxamyl, carbofuran et aldicarbe, employés en repousse, modifient l'équilibre entre les populations d'endoparasites; ils conduisent à la constitution d'un peuplement dominé par Meloidogyne et Pratylenchus en fin de cycle. Par contre sur le témoin, à partir de la seconde repousse, les populations de Paratylenchus, Hoplolaimus et Heterodera deviennent plus importantes que celles de Meloidogyne et Pratylenchus. Helicotylenchus est plus affecté par les fluctuations saisonnières que par les traitements

Artifacts associated with the measurement of oxidized DNA bases.

In this paper we review recent aspects of the measurement of oxidized DNA bases, currently a matter of debate. There has long been an interest in the determination of the level of oxidized bases in cellular DNA under both normal and oxidative stress conditions. In this respect, the situation is confusing because variations that may be as large as two orders of magnitude have been reported for the yield of the formation of 8-oxo-7,8-dihydroguanine (8-oxoGua) in similar DNA samples. However, recent findings clearly show that application of several assays like gas chromatography-mass spectrometry (GC-MS) and -32P--postlabeling may lead to a significant overestimation of the level of oxidized bases in cellular DNA. In particular, the silylation step, which is required to make the samples volatile for the GC-MS analysis, has been shown to induce oxidation of normal bases at the level of about one oxidized base per 10(4) normal bases. This has been found to be a general process that applies in particular to 8-oxoGua, 8-oxo-7, 8-dihydroadenine,5-hydroxycytosine, 5-(hydroxymethyl)uracil, and 5-formyluracil. Interestingly, prepurification of the oxidized bases from DNA hydrolysate prior to the derivatization reaction prevents artefactual oxidation. Under these conditions, the level of oxidized bases measured by GC-MS is similar to that obtained by HPLC associated with electrochemical detection (HPLC-EC). It should be added that the level of 8-oxo-7,8-dihydro-2;-deoxyguanosine in control cellular DNA has been found to be about fivefold lower than in earlier HPLC-EC measurements by using appropriate conditions of extraction and enzymatic digestion of DNA. Similar conclusions were reached by measuring formamidopyrimidine-DNA glycosylase sensitive sites as revealed by the single cell gel electrophoresis (comet) assay

African-American patients with cancer Talking About Clinical Trials (TACT) with oncologists during consultations: evaluating the efficacy of tailored health messages in a randomised controlled trial—the TACT study protocol

Introduction Low rates of accrual of African-American (AA) patients with cancer to therapeutic clinical trials (CTs) represent a serious and modifiable racial disparity in healthcare that impedes the development of promising cancer therapies. Suboptimal physician–patient consultation communication is a barrier to the accrual of patients with cancer of any race, but communication difficulties are compounded with AA patients. Providing tailored health messages (THM) to AA patients and their physician about CTs has the potential to improve communication, lower barriers to accrual and ameliorate health disparities. Objective (1) Demonstrate the efficacy of THM to increase patient activation as measured by direct observation. (2) Demonstrate the efficacy of THM to improve patient outcomes associated with barriers to AA participation. (3) Explore associations among preconsultation levels of: (A) trust in medical researchers, (B) knowledge and attitudes towards CTs, (C) patient-family member congruence in decision-making, and (D) involvement/information preferences, and group assignment. Methods and analysis First, using established methods, we will develop THM materials. Second, the efficacy of the intervention is determined in a 2 by 2 factorial randomised controlled trial to test the effectiveness of (1) providing 357 AA patients with cancer with THM with 2 different ‘depths’ of tailoring and (2) either providing feedback to oncologists about the patients\u27 trial THM or not. The primary analysis compares patient engaged communication in 4 groups preconsultation and postconsultation. Ethics and dissemination This study was approved by the Virginia Commonwealth University Institutional Review Board. To facilitate use of the THM intervention in diverse settings, we will convene ‘user groups’ at 3 major US cancer centres. To facilitate dissemination, we will post all materials and the implementation guide in publicly available locations

Palaeoceanographic implications of new and revised bio-chronostratigraphic constraints from the Profitis Ilias Unit (Rhodes, Greece)

Middle Oxfordian-early Kimmeridgian radiolaria, extracted from the top of radiolarites of Profitis Ilias unit (Rhodes island), suggest that the latter are essentially Middle Jurassic in age and the overlying siliceous shales Late Jurassic. The previously identified Calpionellid horizon at the top of Profitis Ilias siliceous marls is now regarded as early Valanginian in age. The above chronostratigraphic constraints allow tentative correlations to be made between Profitis Ilias and Pindos-Olonos sedimentary units. Finally, the palaeoceanographic significance of the studied series in Rhodes and potentially similar pelagic sequences in the Marmaris area of Turkey are discussed

Dextran sulfate enhances the level of an oxidative DNA damage biomarker, 8-oxo-7,8-dihydro-2'-deoxyguanosine, in rat colonic mucosa.

International audienceDextran sodium sulfate (DSS) given in drinking water can induce colonic inflammation and produce colorectal tumors in rodents, although it is not directly genotoxic. The hypothesis that DSS can produce free radicals and induce oxidative DNA damage in colonic mucosa has been tested. In rats fed for 2 days with water containing 3% and 6% DSS, colonic inflammation manifestations were recorded and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), a major biomarker of oxidative DNA damage, was assayed in colonic mucosa. As compared with control rats given pure water, inflammatory manifestations were seen in rats given DSS. At the same time, 8-oxodGuo levels in colonic mucosa were doubled (P < 0.001). These results suggest that formation of oxidative DNA damage in colonic mucosa depends on inflammation and maybe on the production of reactive oxygen species. This study shows that DSS can induce oxidative DNA damage within only 2 days, which could explain in part its carcinogenic properties

Toward the understanding of DNA fluorescence : The singlet excimer of cytosine

By using the multiconfigurational second-order perturbation method CASPT2, including corrections for the basis set superposition error, the lowest-singlet excited state of the face-to-face π-stacked cytosine homodimer is revealed to be bound by about half an eV, being the source of an emissive feature consistent with the observed redshifted [email protected] [email protected] [email protected] [email protected]

Evaluating research impact: The development of a research for impact tool

© 2016 Tsey, Lawson, Kinchin, Bainbridge, McCalman, Watkin, Cadet-James and Rossetto. Introduction: This paper examines the process of developing a Research for Impact Tool in the contexts of general fiscal constraint, increased competition for funding, perennial concerns about the over-researching of Aboriginal and Torres Strait Islander issues without demonstrable benefits as well as conceptual and methodological difficulties of evaluating research impact. The aim is to highlight the challenges and opportunities involved in evaluating research impact to serve as resource for potential users of the research for impact tool and others interested in assessing the impact of research. Materials and methods: A combination of literature reviews, workshops with researchers, and reflections by project team members and partners using participatory snowball techniques. Results: Assessing research impact is perceived to be difficult, akin to the so-called "wicked problem," but not impossible. Heuristic and collaborative approach to research that takes the expectations of research users, research participants and the funders of research offers a pragmatic solution to evaluating research impact. The logic of the proposed Research for Impact Tool is based on the understanding that the value of research is to create evidence and/or products to support smarter decisions so as to improve the human condition. Research is, therefore, of limited value unless the evidence created is used to make smarter decisions for the betterment of society. A practical way of approaching research impact is, therefore, to start with the decisions confronting decision makers whether they are government policymakers, industry, professional practitioners, or households and the extent to which the research supports them to make smarter policy and practice decisions and the knock-on consequences of doing so. Embedded at each step in the impact planning and tracking process is the need for appropriate mix of expertise, capacity enhancement, and collaborative participatory learning-by-doing approaches. Discussion: The tool was developed in the context of Aboriginal and Torres Strait Islander research but the basic idea that the way to assess research impact is to start upfront with the information needs of decisions makers is equally applicable to research in other settings, both applied (horizontal) and basic (vertical) research. The tool will be further tested and evaluated with researchers over the next 2 years (2016/17). The decision by the Australian Government to include 'industry engagement' and 'impact' as additions to the Excellence in Research for Australia (ERA) quality measures from 2018 makes the Research for Impact Tool a timely development. The wider challenge is to engage with major Australian research funding agencies to ensure consistent alignment and approaches across research users, communities, and funders in evaluating impact