A mixed‐effect model for positive responses augmented by zeros

In this research article, we propose a class of models for positive and zero responses by means of a zero‐augmented mixed regression model. Under this class, we are particularly interested in studying positive responses whose distribution accommodates skewness. At the same time, responses can be zero, and therefore, we justify the use of a zero‐augmented mixture model. We model the mean of the positive response in a logarithmic scale and the mixture probability in a logit scale, both as a function of fixed and random effects. Moreover, the random effects link the two random components through their joint distribution and incorporate within‐subject correlation because of the repeated measurements and between‐subject heterogeneity. A Markov chain Monte Carlo algorithm is tailored to obtain Bayesian posterior distributions of the unknown quantities of interest, and Bayesian case‐deletion influence diagnostics based on the q‐divergence measure is performed. We apply the proposed method to a dataset from a 24hour dietary recall study conducted in the city of São Paulo and present a simulation study to evaluate the performance of the proposed methods. Copyright © 2015 John Wiley & Sons, Ltd.     

Recent US Case of Variant Creutzfeldt-Jakob Disease—Global Implications

Variant Creutzfeldt-Jakob disease (vCJD) is a rare, fatal prion disease resulting from transmission to humans of the infectious agent of bovine spongiform encephalopathy. We describe the clinical presentation of a recent case of vCJD in the United States and provide an update on diagnostic testing. The location of this patient’s exposure is less clear than those in the 3 previously reported US cases, but strong evidence indicates that exposure to contaminated beef occurred outside the United States more than a decade before illness onset. This case exemplifies the persistent risk for vCJD acquired in unsuspected geographic locations and highlights the need for continued global surveillance and awareness to prevent further dissemination of vCJD.     

Pulmonary injuries and cytokine levels after the intraperitoneal administration of pancreatic homogenates in rats.

INTRODUCTION: Our objective was to investigate the effects of the administration of pancreatic homogenates, with or without enzymatic activation, to healthy animals regarding cytokine serum levels and the development of pulmonary distress. MATERIAL AND METHODS: 106 male Wistar rats, divided into three groups, were studied: group A, intraperitoneal administration of homogenates activated with enterokinase; group B, homogenates without enterokinase; and group C, control group with administration of physiological saline solution. Each group was divided into 4 subgroups according to the time of sacrifice: 0, 2, 6 and 24 hours. We studied the pulmonary and pancreatic histology, serum parameters of renal and hepatic function, and serum levels of IL-1beta, IL-6 and TNFalpha. RESULTS: There was no mortality in any group. Pancreatic disorders in A and B groups were noted at 24 hours. These two groups had statistically significant higher transaminase serum levels than those of the control group, as well as statistically significant higher creatinine levels in group A. IL-1beta showed a statistically significant higher level at 6 h in both groups, A and B, but was higher in group A, which also exhibited significant pulmonary histologic damage with respect to controls at 6 h. CONCLUSIONS: The higher IL-1beta level in group A may result from production by peritoneal macrophages under the influence of homogenate enzymatic activation. This may be the reason for lung damage.