The role of oxidative stress in neuromelanin synthesis in PC12 cells.

Previous research has indicated that neuromelanin (NM) is involved in the pathogenesis of Parkinson's disease (PD). Increased reactive oxygen species (ROS) generation in PD sufferers is thought to be related to enhanced tyrosine hydroxylase (TH) activity and NM production. However, few reports have confirmed this hypothesis. In this study, PC12 cells of all experiments were exposed to 50 µmol/L levodopa (l-DOPA) to generate a model for NM synthesis. Meanwhile, PC12 cells were treated with glucose oxidase (GO) at different concentrations to generate oxidative stress. Finally, cell viability, TH activity, and NM generation in PC12 cells were measured. The results showed that GO dose-dependently stimulated oxidative stress generation in PC12 cells. Moderate increases in oxidative stress enhanced the viability of PC12 cells. However, an excessive level of oxidative stress can lead to the degeneration of PC12 cells. Notably, in the surviving PC12 cells, ROS significantly increased the TH activity, and the NM production was also upregulated. Thus, oxidative stress may upregulate the synthesis of NM, which may be a result of the increased TH activity observed in response to the elevated ROS in l-DOPA-treated PC12 cells.

[Reconstruction of forearm function by fibular transfer with vascular anastomoses].

OBJECTIVE: To analyse and report the reconstruction of forearm function by fibular transfer with vascular anastomoses. METHODS: Fourteen cases of forearm function dismissed due to defects of bone were managed by fibular transfer with vascular anastomoses. RESULTS: All cases obtained satisfactory effects, and recovered their normal function. CONCLUSION: The vascularized fibular transfer is a good method to reconstruct the forearm function with defects of bone resulting from injury or tumor.