B and δ11B biogeochemical cycle in a beech forest developed on a calcareous soil: Pools, fluxes, and forcing parameters.

Rock weathering and biological cycling hold the development and sustainability of continental ecosystems, yet the interdependence of macro- and micro-nutrients biogeochemical cycles and their implications for ecosystem functioning remains unclear, despite being of particular importance in the context of global changes. This study focuses on the stocks, fluxes and processes constituting the biogeochemical cycle of boron. Vegetation, soils and solutions were monitored for a full year in a temperate beech forest developed on calcareous soil. Despite an overwhelmingly large B pool in soils, this study points to limited influence of weathering emphasizing the importance of vegetation cycling on this site. The biological imprint on the B cycle is marked by (1) a strong 11B enrichment of solutions compared to the mineral source and (2) systematic correlations observed between B and other strongly recycled elements in all water samples. B isotopes are fractionated within the beech stand with higher values in leaves (23.5‰) and lower in fine roots (-11.7‰), suggesting that the light 10B isotope is preferentially assimilated during plant growth. B isotopic data are consistent with a Rayleigh-like behaviour during xylem transfer leading to an 11B enrichment in the higher parts of the trees, putting internal B transfer as the main driver of the large range of isotopic compositions between plant tissues. B apparent isotopic fractionations are observed in the annually produced biomass and total beech stand, albeit with different values: αxylem-biomass = 0.980 ± 0.009 and 0.990 ± 0.002, respectively, suggesting 11B transfer from old to new tissue. The developed model also points to an isotopic fractionation factor during B uptake much higher than previously evaluated (0.979 < αuptake < 0.994). Overall, this study demonstrates that B isotopes appear as a promising tracer of soil-plant interactions with particular emphasis on tree adaptation to B bioavailability in soil.

Assessment of the bioavailability and depuration of uranium, cesium and thorium in snails (Cantareus aspersus) using kinetics models.

Uranium ore waste has led to soil contamination that may affect both environmental and soil health. To analyze the risk of metal transfer, metal bioavailability must be estimated by measuring biological parameters. Kinetic studies allow taking into account the dynamic mechanisms of bioavailability, as well as the steady state concentration in organisms necessary to take into account for relevant risk assessment. In this way, this work aims to model the snail accumulation and excretion kinetics of uranium (U), cesium (Cs) and thorium (Th). Results indicate an absence of Cs and Th accumulation showing the low bioavailability of these two elements and a strong uranium accumulation in snails related to the levels of soil contamination. During the depuration phase, most of the uranium ingested was excreted by the snails. After removing the source of uranium by soil remediation, continued snails excretion of accumulated uranium would lead to the return of their initial internal concentration, thus the potential trophic transfer of this hazardous element would stop.

[Cognitive remediation therapy for children: literature data and clinical application in a child and adolescent psychiatry department]. / Thérapie par remédiation cognitive chez les enfants : données de la littérature et application clinique dans un service de psychiatrie de l'enfant et de l'adolescent.

The hypothesis of cerebral plasticity in psychiatric disorders has encouraged clinicians to develop cognitive remediation therapy (CRT), a new therapeutic approach based on attention, memory, planning, and mental flexibility tasks. The first cognitive remediation programs were developed and validated for adults with schizophrenia and were shown to have a positive impact on executive functions as well as on quality of life. In children and adolescents, researchers emphasized the existence of executive dysfunction in neurodevelopmental disorders such as autistic spectrum disorder, attention deficit disorder, and eating disorders. For these disorders, neuropsychological studies suggest that memory, planning, attention and mental flexibility are impaired. Despite the paucity of studies on cognitive remediation (CR) in children, preliminary results have suggested, as in adults with schizophrenia, good compliance and optimization of executive functioning. Consequently, programs dedicated to young subjects were developed in English-speaking countries, and the Department of Child and Adolescent Psychiatry of Sainte Anne Hospital (Paris) developed a new CR program for children with attention deficit disorder, academic problems, or eating disorders. These programs complete the field of CRT proposed by Sainte Anne Hospital's Remediation and Psychosocial Rehabilitation Reference Center, initially designed for adults with schizophrenia. Our team used and adapted validated tools such as Delahunty and Wykes's CRT program (translated and validated in French by Amado and Franck) and Lindvall and Lask's CRT Resource Pack. One program was developed for an adolescent with anorexia nervosa and applied to the subject and her family, but the purpose of this paper is to present a CR approach for children with attention deficit disorder or academic disorder, a 6-month program based on paper-pencil tasks and board and card games. The team was trained in different kinds of cognitive remediation, and the program was applied by a clinical nurse with the supervision of a child and adolescent psychiatrist and the department's neuropsychologists. Paper-pencil tasks were adapted from the CRT program for adults; the card and board games used were geometric figures, illusions, Rush Hour(®), Set(®), Jungle Speed(®), Color Addict(®), etc. These games are available in stores and the program can be applied at home, which helps families set aside their preoccupations with their child's academic performance. Diagnostic and neuropsychological evaluations were done before the beginning of the therapy and repeated at the end of the 6-month program. This program does not ignore the metapsychological impact of the therapy, and work on self-esteem is also done. The presence of the therapist is necessary, which seems better than a computer program, which cannot encourage the young subject in the same personalized and empathetic way. We therefore conducted the first clinical feasibility trial of cognitive remediation in young subjects and present a clinical case of a 6-year-old boy with attention deficit disorder and academic disorder. The results of neuropsychological evaluations before and after therapy suggest improvement in executive functions and better self-esteem. Satisfaction for the boy and his family was high. Even if these results need to be replicated, cognitive remediation appears to be a new therapeutic tool, complementary to classical approaches used in childhood psychiatric disorders. The Department of Child and Adolescent Psychiatry will submit this program to a research program conducted by the National Health Department to study the impact of this approach in a controlled study.

Arteriolar renin and vascular effects of angiotensin II in juxtamedullary nephrons.

The SJMNs made accessible in the in vitro juxtamedullary nephron preparation possess an arteriolar renin and Ang II distribution similar to other nephron populations; renin-rich cells prevail in the JAA. Physiological studies have documented that exogenous Ang II constricts both pre- and postglomerular vessels of SJMNs. However, Ang II predominantly increases afferent resistance along the JAA. A functional interaction between Ang II and prostaglandins is likely to occur in preglomerular vessels and deserves further assessment. An additive, functional interaction was demonstrated between Ang II and autoregulation in afferent arterioles. Calcium channel blockers interfere with Ang II-induced constriction only in preglomerular vessels of SJMNs.

[Demonstration of direct vasoconstrictive effect of cyclosporin on glomeruli isolated from human kidney]. / Mise en évidence de l'effet vasoconstricteur direct de la cyclosporine sur glomérules isolés de rein humain.

Cyclosporin (CsA), a potent immunosuppressive agent, can induce severe renal damage, characterized by lesions in the tubulo interstitial region and decreased renal function. Isolated glomeruli can be considered as a fruitful model to evidence the direct effect of drugs at the level of glomerular structures. The present study aims to evidence, in this model, vasoactive response of isolated human renal glomeruli induced by different CsA concentrations. Area changes of such isolated glomeruli can be assessed by a semi-automatic morphometric method, using a video-camera device coupled with a microprocessor (Biocom 2000). Experiments are done under double bind conditions. CsA-induced decrease in glomeruli area is dose- and time-dependent. CsA effect is rapid in that glomerular area is significantly decreased even after 5 min. incubation; vasoconstrictive effect is more important (and maximum) after 10 min. incubation; significant decrease can be noted with 10(-7) M (-11.41%) and 10(-6) M (-10.26%). In conclusion, the isolated glomerulus model allows us to demonstrate the direct vasoconstrictive effect of CsA, that can in part explain the renal functional changes and the acute renal failure often described in human clinic.