Objectives: Methohexital, a barbiturate anesthetic commonly used for electroconvulsive therapy (ECT), possesses dose-dependent anticonvulsant properties, and its use can interfere with effective seizure therapy in patients with high seizure thresholds. Ketamine, an N-methyl-d-aspartate antagonist with epileptogenic properties not broadly used for ECT inductions, is a commonly used induction agent for general anesthesia. Recent studies suggest that the use of ketamine is effective in allowing successful ECT treatment in patients with high seizure thresholds without an increase in adverse effects.
View Article and Find Full Text PDFQuorum sensing triggers virulence factor expression in medically important bacterial pathogens in response to a density-dependent increase in one or more autoinducing pheromones. Here, we show that phagocyte-derived oxidants target these autoinducers for inactivation as an innate defense mechanism of the host. In a skin infection model, expression of phagocyte NADPH oxidase, myeloperoxidase, or inducible nitric oxide synthase was critical for defense against a quorum-sensing pathogen, Staphylococcus aureus, but not for defense against a quorum sensing-deficient mutant.
View Article and Find Full Text PDFStaphylococcus aureus undergoes a density-dependent conversion in phenotype from tissue-adhering to tissue-damaging and phagocyte-evading that is mediated in part by the quorum-sensing operon, agr, and its effector, RNAIII. Contributions of host factors to this mechanism for regulating virulence have not been studied. We hypothesized that fibrinogen, as a component of the inflammatory response, could create spatially constrained microenvironments around bacteria that increase density independently of bacterial numbers and thus potentiate quorum-sensing-dependent virulence gene expression.
View Article and Find Full Text PDFIntegrin ligation activates both cell adhesion and signal transduction, in part through reorganization of the actin cytoskeleton. Plastins (also known as fimbrins) are actin-crosslinking proteins of the cortical cytoskeleton present in all cells and conserved from yeast to mammals. Here we show that plastin-deficient polymorphonuclear neutrophils (PMN) are deficient in killing the bacterial pathogen Staphylococcus aureus in vivo and in vitro, despite normal phagocytosis.
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