Labile zinc concentration and free copper ion activity in the rhizosphere of forest soils.

Water-soluble and acid-extractable Cu and Zn, water-soluble organic carbon (WSOC), pH, differential pulse anodic stripping voltammetry-labile Zn (ZnL), Zn2+ activity (Windemere humic aqueous model [WHAM]; http://chess.ensmp.fr/ chemsites.html), and Cu2+ activity with an ion-selective electrode were compared between the rhizosphere and the bulk components of nine acidic forest sites from southeastern Canada. At all sites, the WSOC contents were higher in the rhizosphere than in the bulk component. Acidity was also higher in the rhizosphere, although pH differences were significant at only five sites. The concentrations of Zn in water extracts and ZnL contents (at six sites) were higher in the rhizosphere, whereas acid-extractable Zn was only marginally increased in the rhizosphere. Calculations with WHAM indicated that free Zn2+ ion activities were higher in the rhizosphere than in the bulk soil but that the fraction of total dissolved Zn in water extracts that is present as free Zn2+ did not differ significantly between the two components. The concentration of Cu in the water extract was higher in the rhizosphere for all sites, but acid-extractable Cu levels did not differ. The fraction of water-soluble Cu present as Cu2+ was higher in the bulk soil, although Cu2+ activities did not significantly vary with proximity to roots. These results showed that the processes acting in the rhizosphere of forest soils strongly affected the concentrations of dissolved Zn and Cu and that this microenvironment should be considered when estimating the bioavailability and the ecological risks of metals in soils.

[Qualitative assessment of the multidisciplinary tumor board in breast cancer]. / Evaluation qualitative de la réunion de concertation pluridisciplinaire de cancérologie mammaire.

The optimal care for breast cancers requires at a given time that several practitioners meet regularly around the file of the patient and attend a multidisciplinary meeting (MDM). Such an initiative is not recent. The multidisciplinary approach has been applied for several years in numerous comprehensive cancer centres, and noteworthy but not exclusively in the 20 regional cancer centres. Recommendations on the organization of the MDM were published by the National Institute of the Cancer and relieved by each regional cancer networks according to the Cancer Plan of 2003. Beyond these general recommendations, the purpose of this work was to analyse the impact of the MDM on the appraisal of the professional practices. Two retrospective surveys were carried out in 2005 and in 2006 at the regional cancer centre of Reims each of them during the first 6 months of the year. They lead to a double evaluation at the same moment of the organization of the MDM (delays, exhaustiveness of the file presentation, multidisciplinary approach, and modalities of application of the clinical recommendations by the MDM). The authors suggest, from the observed results, that MDM in breast cancer research may be strongly adapted for a fine and relevant assessment of the professional practices. The specific indicators presented in this study need further discussions and will probably evolve. However and considering the important improvement observed in the clinical daily practice following the presentation of these data within the Institute Jean Godinot, the authors suggest the implementation of a similar evaluation in a small number of voluntary health care centres in order to share various experiences and validate the process.