Do polymethylmethacrylate particles stimulate bone resorption of mature osteoclasts in vitro?
Treatment of mature osteoclasts with PMMA particles resulted in an elevated number of TRAP-positive cells. This persisted over a longer period of time than at the other stages of osteoclast development, and there was also a greater increase in bone resorption.
Results indicate that catecholamines' degradation products possessing methoxy (-OCH3) groups can rapidly inhibit in vitro and ex vivo epinephrine-induced platelet aggregation. The inhibitory effects of methoxy phenolic derivatives on epinephrine-induced platelet aggregation may possibly be attributed to their free radical scavenging properties. There is substantial evidence to conclude that an internal rapid autoregulation of epinephrine-induced platelet aggregation, caused by its metabolic degradation products, takes place in vivo.