Acknowledgements
The authors thank the patients for their participation in this study. The authors also thank the staff at the Massachusetts Institute of Technology, Nuclear Reactor Laboratory: L. Hu, J. Maro, J. Che, and J. Idell. Funding was provided by the Digiovanni ALS Research Fund at MGH. R. H. Brown's ALS research program receives generous support from the ALS Therapy Alliance, the Angel Fund, the de Bourgknecht Fund for ALS research, Project ALS and the National Institute for Neurological Disorders and Stroke at the N. I. H. The authors express their gratitude to Merrill Cohen for many useful discussions related to toxicity and measurements of vanadium.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.