Unconjugated bilirubin (UCB) is a neurotoxic degradation product of heme. Its toxic effects include induction of apoptosis, and ultimately neuronal cell death. However, at low concentrations, UCB is a potent antioxidant that may protect cells and tissues against oxidative stress by neutralizing toxic metabolites such as reactive oxygen species (ROS).
View Article and Find Full Text PDFComplement, an important effector mechanism of the immune system, is an enzymatic cascade of approx. 30 serum proteins leading to the amplification of a specific humoral response. It can be activated through the classical or alternative pathways, or through the mannose-binding lectin pathway.
View Article and Find Full Text PDFBiologically active molecules, that is pharmaceuticals and other chemical substances, exert their therapeutic and/or toxic effects by complex interactions with their biological targets/active sites. This review discusses the factors and processes governing the kinetics and effects of active molecules at their cellular targets, the chain of events leading to clinical effects, and the crosstalk between regulatory pathways controlling these processes. Special attention is given to the discussion of effects of a single drug or other chemical on multiple targets, to the interaction of multiple ligands with a single target/receptor and the effects of single ligand-target complexes on multiple signal transduction pathways, and to the control of physiological functions, such as regulation of blood glucose levels, by numerous primary mechanisms acting on different cellular targets.
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