Tumor Necrosis Factora

Tumor necrosis factor-a (TNF-a) is a major proinflammatory cytokine secreted in increased amounts by macrophages and endothelial cells in situations linked pulmonary edema formation, such as pneumonia, sepsis, systemic inflammation and injury. TNF-a has been implicated in endothelial cell activation, endothelial cell death by apop-tosis, and increased vascular permeability. The mechanisms by which TNF-a triggers endothelial barrier disruption include contraction of the intracellular actin microfilaments and formation of inter-cellular gaps that parallel in time the development of trans-endothelial permeability [2]. The rearrangement of the actin-based cytoskeleton is the result of actin-myosin movement, which, as in muscle cells, follows the phosphorylation of the myosin light chains. TNF-a induces significant actin microfilaments contraction via myosin light chain phosphorylation, a reaction catalyzed by both myosin light chain kinase (MLCK) and Rho kinase. However, inhibition of either enzyme does not prevent TNF-a-induced endothelial barrier dysfunction [2], suggesting that MLCK-independent microfilament changes and/or other cytoskeletal structures, such as intermediate filaments, microtubules, and adherens junctions, may be involved.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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