Effect of fire on a monodominant floating mat of Cyperus giganteus Vahl in a neotropical wetland.

The rhizomatous Cyperus giganteus, abundant in the Pantanal wetland, can dominate extense floodable areas as monodominant communities. The Jacadigo lake has a large area of C. giganteus, where we performed an evaluation on community structure during two months in 2010, before it was hit by a wildfire which top-killed the vegetation, compared to ten months post-fire. We utilized 40 plots of 1m × 1m, along permanent trails, assessing two strata: the upper, near the inflorescence of adult plants, and the lower, close to the water level. Our results show that fire does not affect dominance of C. giganteus, as it maintained the same cover as before fire; species richness is not much altered either - 28 before fire and 34 thereafter. Fire changed the floristic composition, due to the annual variation of species and the ability of some plants to colonize gaps and to regrow after fire from underground organs and seeds. The stratification of the vegetation with characteristic species of upper and lower strata was similar after fire.

Can pre-liver transplantation renal insufficiency using a creatinine clearance calculator predict long-term survival?

INTRODUCTION: Renal insufficiency can be associated with poor long-term survival of liver transplant recipients. OBJECTIVE: The objective of this study was to study renal insufficiency observed pretransplantation and its long-term impact after liver transplantation. METHODS: We analyzed retrospectively an electronic database collected prospectively including transplant records from June 1994 to October 2010 using piggyback venous reconstruction. The exclusion criteria were chronic kidney disease, acute hepatic failure, children up to 12 years of age, and retransplantations. Renal insufficiency was defined by the creatinine clearance (CCr) calculated using the Cockcroft-Gault method. Patients were distributed into 3 groups: CCr >90, between 90 and 60, and >60 mL/min/1.73 m(2). The survival rate was calculated using the Kaplan-Meier method and proportional hazards Cox regression analysis using death and CCr as stratifying variables evaluated predictive factors for survival. The groups were compared using the Kruskal-Wallis test with significant differences at P < .05. RESULTS: Among the 305 patients those who showed preoperative and postoperative CCR of >90 were 187/59.9% and 82/26.3%, 60 to 90 were 77/24.7% and 74/23.7%, or <60 mL/min/1.73 m(2) were (41/13.1% and 149 (47.7%). Patients with preoperative CCr <60 mL/min/1.73 m(2) showed worse short- and long-term survivals as well as the longest intensive care unit and hospital stays (P = .034). The only predictive donor factor was age older than 40 years namely, the greatest hemotransfusion needs and postoperative liver and renal dysfunction (Chi square = 100.6064; P = .00001). The area under the curve (AUC) obtained using an receiver operating characteristic (ROC) analysis was 0.563 (95% CI 0.498-0.627) with a cut off of 30.25. CONCLUSION: Pre-liver transplantation renal insufficiency seemed to be a predictive factor for long-term survival.