Involvement of the actin cytoskeleton and p21rho-family GTPases in the pathogenesis of the human protozoan parasite Entamoeba histolytica

It has been estimated that infection with the enteric protozoan parasite Entamoeba histolytica kills more than 50,000 people a year. Central to the pathogenesis of this organism is its ability to directly lyse host cells and cause tissue destruction. Amebic lesions show evidence of cell lysis, tissue necrosis, and damage to the extracellular matrix. The specific molecular mechanisms by which these events are initiated, transmitted, and effected are just beginning to be uncovered. In this article we review what is known about host cell adherence and contact-dependent cytolysis. We cover the involvement of the actin cytoskeleton and small GTP-binding proteins of the p21rho-family in the process of cell killing and phagocytosis, and also look at how amebic interactions with molecules of the extracellular matrix contribute to its cytopathic effects

Argumentation in Foreign Policy Settings

This is a study of argumentation in three different kinds of high level, confidential, foreign policy settings: a collegial setting, a bureaucratic setting, and a bargaining setting. The causal and value assertions of the participants were coded using the detailed records of these three settings. The data show to be inadequate a defense/ attack model of argumentation in which the participants support their own arguments to make them resistant to attack, while attacking the weak spots in others'stated positions. In fact, there are few assertions which are supported by specific evidence, almost no mutually supported causal arguments, and the assertions which were attacked were no less emphasized than the assertions which were not attacked. More in accord with the data is the novel-arguments approach in which the key factor in persuasive argumentation is the development of arguments which others have not already taken into account.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67391/2/10.1177_002200277702100410.pd