Pretransplant Prediction of Posttransplant Survival for Liver Recipients with Benign End-Stage Liver Diseases: A Nonlinear Model

Background: The scarcity of grafts available necessitates a system that considers expected posttransplant survival, in addition to pretransplant mortality as estimated by the MELD. So far, however, conventional linear techniques have failed to achieve sufficient accuracy in posttransplant outcome prediction. In this study, we aim to develop a pretransplant predictive model for liver recipients ’ survival with benign end-stage liver diseases (BESLD) by a nonlinear method based on pretransplant characteristics, and compare its performance with a BESLD-specific prognostic model (MELD) and a generalillness severity model (the sequential organ failure assessment score, or SOFA score). Methodology/Principal Findings: With retrospectively collected data on 360 recipients receiving deceased-donor transplantation for BESLD between February 1999 and August 2009 in the west China hospital of Sichuan university, we developed a multi-layer perceptron (MLP) network to predict one-year and two-year survival probability after transplantation. The performances of the MLP, SOFA, and MELD were assessed by measuring both calibration ability and discriminative power, with Hosmer-Lemeshow test and receiver operating characteristic analysis, respectively. By the forward stepwise selection, donor age and BMI; serum concentration of HB, Crea, ALB, TB, ALT, INR, Na +; presence of pretransplant diabetes; dialysis prior to transplantation, and microbiologically proven sepsis were identified to be the optimal input features. The MLP, employing 18 input neurons and 12 hidden neurons, yielded high predictive accuracy, wit

Adapting sheep production to climate change

Apart from contributing to the climate change phenomenon, sheep production sys tem is also sensitive to its adverse impacts. This poses a great challenge for develop ing sheep sector around the world. Currently the economic viability of the sheep production system worldwide is jeopardized due to the devastating effects of cli mate change. Among the multiple climatic stresses faced by sheep, heat stress seems to hugely destabilize production efficiency of the animals. Heat stress jeopardizes the growth, wool, meat and milk production in sheep. Further, climate change leads to several vector borne diseases to sheep by compromising the immune status of the animals. The animal employs several adaptive mechanisms to maintain homeosta sis through behavioural, physiological, neuroendocrine, cellular and molecular responses to cope up to the existing climatic condition. Sheep also significantly contributes to climate change through enteric methane emission and manure man agement. Further, climate change can alter the rumen function and diet digestibility in sheep. Hence, enteric methane mitigation is of paramount importance to prevent both the climate change and dietary energy loss which may pave way for sustaining the economic return from these animals. Further, various other strategies are required to counter the detrimental effects of climate change on sheep production. The management strategies can be categorized as housing management, animal management and monitoring of climate, and these strategies are ultimately targeted to provide suitable microclimate for optimum sheep production. Nutritional inter ventions involving season-specific feeding and micronutrient supplementation may help the animal to sustain its production during adverse environmental conditions. Body condition scoring system developed specifically for sheep may help to opti mize economic return in sheep farms by minimizing the input costs. Finally, suffi cient emphasis must be given to develop appropriate adaptation strategies involving policymakers. These strategies include developing thermotolerant breeds using bio markers, ensured water availability, women empowerment, early warning system and capacity building programmes for all the stakeholders. These efforts may help in augmenting sheep production in the climate change scenario