The Inflammatory Response and Cardiac Repair After Myocardial Infarction

One of the most important therapeutic targets of current cardiology practice is to determine optimal strategies for the minimization of myocardial necrosis and optimization of cardiac repair following an acute myocardial infarction. Myocardial necrosis after acute myocardial infarction induces complement activation and free radical generation, triggering a cytokine cascade initiated by tumor necrosis factor-alpha (TNF-α) release. When reperfusion of the infarcted area is initiated, intense inflammation follows. Chemokines, cytokines and the complement system play an important role in recruiting neutrophils in the ischemic and reperfused myocardium. Cytokines promote adhesive interactions between leukocytes and endothelial cells, resulting in transmigration of inflammatory cells into the site of injury. The recruited neutrophils have potent cytotoxic effects through the release of proteolytic enzymes, and they interact with adhesion molecules on cardiomyocytes. In spite of the potential injury, reperfusion enhances cardiac repair; this may be related to the inflammatory response. Monocyte chemoattractant protein (MCP)-1 is upregulated in reperfused myocardium and can induce monocyte recruitment in the infarcted area. Monocyte subsets play a role in phagocytosis of dead cardiomyocytes and in granulation tissue formation. In addition, the transforming growth factor (TGF)-β plays a crucial role in cardiac repair by suppressing inflammation. Resolution of inflammatory infiltration, containment of inflammation and the reparative response affecting the infarcted area are essential for optimal infarct healing. Here, we review the current literature on the inflammatory response and cardiac repair after myocardial infarction

Effects of kinetics of adsorption and coalescence on continuous foam concentration of proteins

Foam concentration is an adsorptive bubble separation technique in which soluble surface active substances can be concentrated from dilute solution by preferential adsorption at the gas-liquid interface generated by a rising ensemble of bubbles. It was possible to concentrate BSA and $\beta$-casein from 0.01-0.1 wt% and 0.01-0.05 wt% respectively in a continuous foam column because of their surface activity. Enrichments ranged from 1.5-10 and recoveries from 10-30%. The effects of kinetics of adsorption of protein, feed concentration, gas velocity, bubble size, foam height, coalescence, pH and ionic strength on the performance of a foam concentration column were investigated. Gas velocity was varied between 0.13-0.26 cm/s, bubble size between 0.08-0.12 cm, foam height ranged from 7-32 cm, pool height between 2-40 cm, pH from 3-7 and ionic strength from 0.002-0.1 M. Protein enrichment was higher for larger bubble sizes, larger foam heights, lower feed concentrations and smaller gas velocities. A minimum enrichment was found at an intermediate pool height because of opposing effects of kinetics of adsorption and coalescence. Bubble size was minimum at pI of BSA leading to minimum enrichment. Enrichments were insensitive to ionic strength in the range of 0.002-0.1 M. A model for the hydrodynamics of the foam bed was developed accounting for the kinetics of adsorption as well as coalescence. Kinetics of adsorption of proteins was described in terms of surface hydrophobicity, surface pressure and electrostatic interactions. A surface equation of state for globular protein was developed to predict the variation of surface pressure with surface concentration. Coalescence frequencies were evaluated from the experimental measurements of mean bubble size versus foam height using image analysis. Model predicted an upper bound for protein enrichment when only coalescence was accounted for; whereas model predictions accounting only for kinetics of adsorption provided lower bound. Combined effects of coalescence and kinetics of adsorption resulted in a minimum enrichment at an intermediate pool height. Model predictions of protein enrichment at a feed concentration of 0.1 wt% compared well with the experimental data for different pool heights, bubble sizes, gas velocities, foam heights and pH excepting at very low pool heights

Is there nowhere else where we can meet? The postcolonial woman writer and political fiction

The focus of this dissertation is the post-colonial woman who is seen as a plurality or as part of a continuum, in which she moves in various positions, depending on what ideology is imposed on her. The novels of Nadine Gordimer, Nayantara Sahgal and Buchi Emecheta are all concerned with the post-colonial woman, as well as with fragmentation, marginality, displacement and dialogic discourse; with fracture or fission in their narratives; and with female exploitation. Yet Gordimer\u27s main concern is with racial conflicts, Sahgal\u27s with religious strife, and Emecheta\u27s with gender problems. Primarily, all three novelists represent repressed or subaltern figures as presences that are revealed through interactions between various voices, gaps in dominant discourse, overlay, and constant displacement. As regards the alienated elite, the three novelists represent her as an isolated figure who assimilates through sex or social awareness or writing, but who is only partially integrated with patriarchal society. The three novelists also choose several different ways in which to describe how alternate worlds are visualized by post-colonial women. In general, they appear as quests for alternate identities within the genre of family romances, and are accompanied by visions involving a revised sense of identity. Despite these visions, the alternate worlds are largely unachievable. Also, all three novelists examine the actual nature of the new world created by revolution. It is described as a world in crisis in which women become boundary markers of social change. However, all three novelists fail to problematize the role of class in creating each crisis. In conclusion, the post-colonial woman appears to be an ambivalent figure because her position in society is constantly displaced, her voice is always resisting imperial hegemony and her discourse constantly shifts and evolves. She is at once elite and powerless, at once subversive and exploitative