Multicenter Randomized Double-Blind, Placebo-Controlled Trial GORTEC (Groupe Oncologie Radiotherapie Tete et Cou) 2009-01 Evaluating the Effect of the Regenerating Agent on Radiodermatitis of Head and Neck Cancer Patients.

Concomitant cetuximab and radiation therapy (RT) can induce severe radiodermatitis in patients with head and neck cancer (HNC). OTD70DERM, a regenerating agent (RGTA), is a structural and functional analogue of glycosaminoglycans. Preclinical studies have shown that topical RGTA can markedly reduce radiation-induced mucosal and cutaneous toxicities without tumor protection. The present study aimed to evaluate the effect of topical RGTA on radiodermatitis in patients with HNC undergoing RT and cetuximab, for whom RT-induced skin reactions are frequent and/or severe. The primary endpoint was the incidence of grade ≥2 radiodermatitis. We performed a multicenter, randomized, double-blind, placebo-controlled trial of patients with newly diagnosed HNC undergoing conventionally fractionated RT (70 Gy in 35 fractions) and weekly cetuximab. Patients were randomized 1:1 to receive topical OTD70DERM or placebo on irradiated skin once daily. The National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0, was used to evaluate radiodermatitis (photographs of radiation zone). The Dermatology Life Quality Index score was also evaluated. All the skin reactions seen on the photographs were scored independently by 2 outside experts. Of the 76 randomized patients (38 in each arm), 72 were available for the final radiodermatitis evaluation (37 in the RGTA arm and 35 in the placebo arm). No significant difference was observed concerning the incidence or duration of grade ≥2 radiodermatitis between the 2 arms (81% for RGTA vs 80% for placebo; P=.9). Also, no significant difference was found between the 2 arms regarding grade ≥2 radiodermatitis evaluated by the 2 experts using the photographs of 68 patients (76% vs 74%; P=.78). Finally, no significant difference was found in the Dermatology Life Quality Index score (score >10, 15% vs 20%; P=.45). Despite the good preclinical rationale, RGTA did not reduce the incidence and severity of radiodermatitis in patients with HNC

Changes in specific leaf area of dominant plants in temperate grasslands along a 2500-km transect in northern China

Abstract Specific leaf area (SLA) is a key trait with great ecological importance as it correlates with whole plant growth. We aimed to investigate how SLA varies with environmental factors at a geographical scale in temperate grasslands. We measured SLA and mass-based leaf nitrogen content (N mass) of four dominant plant genera along a 2500 km climatic gradient in northern China grassland, and correlated SLA with mean annual precipitation (MAP), mean annual temperature (MAT), soil nitrogen concentration (soil N), soil C:N and N mass. Climate accounts much more for SLA variation than soil variables for Stipa, Cleistogens and Carex. SLA of Stipa is negatively associated with MAP and soil N, while positively with MAT, but Cleistogenes and Carex show the opposite. For Leymus, soil N promotes SLA and accounts for largest fraction of SLA variation. Overall, SLA was positively correlated with N mass in semi-arid regions, but not significant in arid regions. The genus-dependent responses of SLA may have consequences on ecosystem functioning, thus may help to predict the community composition and ecosystem functions under future climate scenario. The finding of SLA-N mass trade-off and its susceptibility to precipitation will advance our understanding on plant resource use strategies

Seasonal Variation in the Capacity for Plant Trait Measures to Predict Grassland Carbon and Water Fluxes

There is a need for accurate predictions of ecosystem carbon (C) and water fluxes in field conditions. Previous research has shown that ecosystem properties can be predicted from community abundance-weighted means (CWM) of plant functional traits and measures of trait variability within a community (FDvar). The capacity for traits to predict carbon (C) and water fluxes, and the seasonal dependency of these trait-function relationships has not been fully explored. Here we measured daytime C and water fluxes over four seasons in grasslands of a range of successional ages in southern England. In a model selection procedure, we related these fluxes to environmental covariates and plant biomass measures before adding CWM and FDvar plant trait measures that were scaled up from measures of individual plants grown in greenhouse conditions. Models describing fluxes in periods of low biological activity contained few predictors, which were usually abiotic factors. In more biologically active periods, models contained more predictors, including plant trait measures. Field-based plant biomass measures were generally better predictors of fluxes than CWM and FDvar traits. However, when these measures were used in combination traits accounted for additional variation. Where traits were significant predictors their identity often reflected seasonal vegetation dynamics. These results suggest that database derived trait measures can improve the prediction of ecosystem C and water fluxes. Controlled studies and those involving more detailed flux measurements are required to validate and explore these findings, a worthwhile effort given the potential for using simple vegetation measures to help predict landscape-scale fluxes

Contrasting responses in leaf nutrient-use strategies of two dominant grass species along a 30-yr temperate steppe grazing exclusion chronosequence

Grazing exclusion practices can be promising restoration techniques where ecosystem degradation follows from rapidly increasing grazing pressure, as widely observed in northern Chinese grasslands. However, the mechanisms of plant-soil interactions responsible for nutrient cycling restoration remain unclear. We examined the functional response of the two most dominant grass species with contrasting nutrient economies to a grazing exclusion chronosequence varying greatly in soil moisture and extractable N and P. The relative biomass of the nutrient acquisitive species Leymus chinensis increased while that of the nutrient conservative Stipa grandis decreased across the chronosequence. Leymus chinensis displayed increasing leaf nutrient concentration and decreasing nutrient resorption with time since grazing exclusion for both N and P. In contrast, S. grandis showed decreasing leaf N and P concentrations and largely stable nutrient resorption. These differences in plasticity, with respect to nutrient stoichiometry and resorption, suggest contrasting abilities of these two dominant species to compete for soil resources and/or differences in their affinity to the changing forms of soil available N and P likely occurring along the restoration gradient. Ecosystem trajectory of change after grazing exclusion appears therefore largely dependent on the nutrient use strategies of co-occurring dominant grassland species