6 research outputs found
Extensions of Markov Chain Marginal Bootstrap
No full text92 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2003.The Markov chain marginal bootstrap (MCMB) is a new bootstrap method proposed by He and Hu (2002) for constructing confidence intervals or regions based on likelihood equations. It is designed to ease the computational burden of bootstrap in high-dimensional problems. It differs from the usual bootstrap methods in two aspects: a set of p one-dimensional equations is solved in place of a p-dimensional system of equations for each bootstrap estimate of the parameter; the resulting estimates form a Markov chain rather than an independent sequence of realizations. This thesis proposes two modifications to extend the use of MCMB to more general models and estimators. The first modification is a transformation of the parameter space, which reduces high autocorrelation of the resulting MCMB chains, and improves on the efficiency and stability of the procedure. The second is a transformation of the estimating equations, which extends the use of MCMB beyond the likelihood-based estimators. Through examples and Monte Carlo simulations, the transformations proposed in this thesis are shown to be valuable and sometimes necessary for successful applications of MCMB to linear and nonlinear models.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD
Differential metabolic responses to pluronic in MDR and non-MDR cells: A novel pathway for chemosensitization of drug resistant cancers
No full textReduced cardiac output is associated with decreased mitochondrial efficiency in the non-ischemic ventricular wall of the acute myocardial-infarcted dog.
Full text linkCardiogenic shock is the leading cause of death among patients hospitalized with acute myocardial infarction (MI). Understanding the mechanisms for acute pump failure is therefore important. The aim of this study is to examine in an acute MI dog model whether mitochondrial bio-energetic function within non-ischemic wall regions are associated with pump failure. Anterior MI was produced in dogs via ligation of left anterior descending (LAD) coronary artery, that resulted in an infract size of about 30% of the left ventricular wall. Measurements of hemodynamic status, mitochondrial function, free radical production and mitochondrial uncoupling protein 3 (UCP3) expression were determined over 24 h period. Hemodynamic measurements revealed a > 50% reduction in cardiac output at 24 h post infarction when compared to baseline. Biopsy samples were obtained from the posterior non-ischemic wall during acute infarction. ADP/O ratios for isolated mitochondria from non-ischemic myocardium at 6 h and 24 h were decreased when compared to the ADP/O ratios within the same samples with and without palmitic acid (PA). GTP inhibition of (PA)-stimulated state 4 respiration in isolated mitochondria from the non-ischemic wall increased by 7% and 33% at 6 h and 24 h post-infarction respectively when compared to sham and pre-infarction samples. This would suggest that the mitochondria are uncoupled and this is supported by an associated increase in UCP3 expression observed on western blots from these same biopsy samples. Blood samples from the coronary sinus measured by electron paramagnetic resonance (EPR) methods showed an increase in reactive oxygen species (ROS) over baseline at 6 h and 24 h post-infarction. In conclusion, mitochondrial bio-energetic ADP/O ratios as a result of acute infarction are abnormal within the non-ischemic wall. Mitochondria appear to be energetically uncoupled and this is associated with declining pump function. Free radical production may be associated with the induction of uncoupling proteins in the mitochondria
