Determination of Trace Copper in Water Samples by Anodic Stripping Voltammetry at Gold Microelectrode

The applicability of gold microelectrode of 25 mu m diameter for electrochemical determination of trace copper ions (Cu(2+)) in water samples by anodic stripping voltammetry (ASV) has been demonstrated. The analysis of Cu(2+) at gold microelectrode includes two steps. Cu(2+) ions are firstly reduced and accumulated on the microelectrode surface during an accumulation step, then oxidized during the positive potential sweep. Due to the rapid mass transporting and low background current of gold microelectrode, low detection limit (0.3 nM) and wide linear range (1.0-90 nM) can be obtained. The practical application of gold microelectrode was verified by determination of trace level of Cu(2+) in tap water, lake water and commercial drinking water samples

An Epigenomic Approach to Improving Response to Neoadjuvant Cisplatin Chemotherapy in Bladder Cancer

Bladder cancer is among the five most common cancers diagnosed in the Western world and causes significant mortality and morbidity rates in affected patients. Therapeutic options to treat the disease in advanced muscle-invasive bladder cancer (MIBC) include cystectomy and chemotherapy. Neoadjuvant cisplatin-based combination chemotherapy is effective in MIBC; however, it has not been widely adopted by the community. One reason is that many patients do not respond to neoadjuvant chemotherapy, and no biomarker currently exists to identify these patients. It is also not clear whether a strategy to sensitize chemoresistant patients may exist. We sought to identify cisplatin-resistance patterns in preclinical models of bladder cancer, and test whether treatment with the epigenetic modifier decitabine is able to sensitize cisplatin-resistant bladder cancer cell lines. Using a screening approach in cisplatin-resistant bladder cancer cell lines, we identified dysregulated genes by RNA sequencing (RNAseq) and DNA methylation assays. DNA methylation analysis of tumors from 18 patients receiving cisplatin-based chemotherapy was used to confirm in vitro results. Cisplatin-resistant bladder cancer cells were treated with decitabine to investigate epigenetic sensitization of resistant cell lines. Our results show that HOXA9 promoter methylation status is associated with response to cisplatin-based chemotherapy in bladder cancer cell lines and in metastatic bladder cancer. Bladder cancer cells resistant to cisplatin chemotherapy can be sensitized to cisplatin by the DNA methylation inhibitor decitabine. Our data suggest that HOXA9 promoter methylation could serve as potential predictive biomarker and decitabine might sensitize resistant tumors in patients receiving cisplatin-based chemotherapy