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Jadomycins are natural products biosynthesized by the bacteria Streptomyces venezuelae which kill drug-sensitive and multidrug-resistant breast cancer cells in culture. Currently, the mechanisms of jadomycin cytotoxicity are poorly understood; however, reactive oxygen species (ROS)–induced DNA cleavage is suggested based on bacterial plasmid DNA cleavage studies. The objective of this study was to determine if and how ROS contribute to jadomycin cytotoxicity in drug-sensitive MCF7 (MCF7-CON) and taxol-resistant MCF7 (MCF7-TXL) breast cancer cells. As determined using an intracellular, fluorescent, ROS-detecting probe, jadomycins B, S, SPhG, and F dose dependently increased intracellular ROS activity 2.5- to 5.9-fold. Cotreatment with the antioxidant N-acetyl cysteine lowered ROS concentrations to below baseline levels and decreased the corresponding cytotoxic potency of the four jadomycins 1.9- to 3.3-fold, confirming a ROS-mediated mechanism. Addition of CuSO4 enhanced, whereas addition of the Cu(II)-chelator d-penicillamine reduced, the ROS generation and cytotoxicity of each jadomycin. Specific inhibitors of the antioxidant enzymes, superoxide dismutase 1, glutathione S-transferase, and thioredoxin reductase, but not catalase, enhanced jadomycin-mediated ROS generation and anticancer activity. In conclusion, the results indicate that jadomycin cytotoxicity involves the generation of cytosolic superoxide via a Cu(II)-jadomycin reaction, a mechanism common to all jadomycins tested and observed in MCF7-CON and drug-resistant MCF7-TXL cells. The superoxide dismutase 1, glutathione, and peroxiredoxin/thioredoxin cellular antioxidant enzyme pathways scavenged intracellular ROS generated by jadomycin treatment. Blocking these antioxidant pathways could serve as a strategy to enhance jadomycin cytotoxic potency in drug-sensitive and multidrug-resistant breast cancers.

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Background: Ambulatory medication reconciliation can reduce the frequency of medication discrepancies and may also reduce adverse drug events. Patients receiving dialysis are at high risk for medication discrepancies because they typically have multiple comorbid conditions, are taking many medications, and are receiving care from many practitioners. Little is known about the potential benefits of ambulatory medication reconciliation for these patients. Objectives: To determine the number, type, and potential level of harm associated with medication discrepancies identified through ambulatory medication reconciliation and to ascertain the views of community pharmacists and family physicians about this service. Methods: This retrospective cohort study involved patients initiating hemodialysis who received ambulatory medication reconciliation in a hospital renal program over the period July 2014 to July 2016. Discrepancies identified on the medication reconciliation forms for study patients were extracted and categorized by discrepancy type and potential level of harm. The level of harm was determined independently by a pharmacist and a nurse practitioner using a defined scoring system. In the event of disagreement, a nephrologist determined the final score. Surveys were sent to 52 community pharmacists and 44 family physicians involved in the care of study patients to collect their opinions and perspectives on ambulatory medication reconciliation. Results: Ambulatory medication reconciliation was conducted 296 times for a total of 147 hemodialysis patients. The mean number of discrepancies identified per patient was 1.31 (standard deviation 2.00). Overall, 30% of these discrepancies were deemed to have the potential to cause moderate to severe patient discomfort or clinical deterioration. Survey results indicated that community practitioners found ambulatory medication reconciliation valuable for providing quality care to dialysis patients. Conclusions: This study has provided evidence that ambulatory medication reconciliation can increase patient safety and potentially prevent adverse events associated with medication discrepancies.

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