Effects of cell proliferation and cell death (apoptosis and necrosis) on the early stages of rat hepatocarcinogenesis

An experiment was performed to investigate whether, during regressionof the liver hyperplasia induced by a direct mitogen, apoptosisdifferentially affects replicated and non-replicated hepatocytes.After a single dose of the direct mitogen lead nitrate (LN),male Wistar rats were given repeated injections of tritiatedthymidine, and were killed either 3 days (time of maximal hepaticDNA increase) or 15 days (complete regression of the hyperplasia)after mitogen treatment. Determination of liver DNA radioactivitiesand labelling indices (LIs) at the two time points revealedan     

Human plasma fibronectin potentiates the mitogenic activity of platelet-derived growth factor and complements its wound healing effects

Integrin-mediated cell adhesion and growth factor stimuli are both required for optimal control of cell proliferation. In the context of skin injury, cell-derived fibronectin and platelet-derived growth factor play important roles in the stimulation of cell proliferation and migration, activities that are crucial to the healing process. To assess the ability of exogenously supplied plasma-derived fibronectin to stimulate wound repair and to study its ability to cooperate with platelet-derived growth factor-BB during healing, we devised a novel topical delivery formulation that allows the controlled release of both molecules to a wound. Using this topical formulation and the rabbit ear model of dermal wound healing, we show that plasma fibronectin is a potent stimulator of the wound healing process. We also show that administration of fibronectin and platelet-derived growth factor-BB in combination has additive wound healing effects. Finally, we report novel findings on the ability of soluble plasma fibronectin to potentiate the mitogenic effects of platelet-derived growth factor-BB in vitro. These findings not only show that optimal concentrations of exogenous fibronectin administered using an effective delivery system stimulate wound healing; they also suggest that PDGF-BB should be administered with fibronectin to achieve optimal therapeutic stimulation of wound healing.