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Substance use disorders are prevalent, causing extensive morbidity and mortality worldwide. Evidence-based treatments are of low to moderate effect size. Growth in the neurobiological understanding of addiction (e.g., craving) along with technological advancements in neuromodulation have enabled an evaluation of neurosurgical treatments for substance use disorders. Deep brain stimulation (DBS) involves surgical implantation of leads into brain targets and subcutaneous tunneling to connect the leads to a programmable implanted pulse generator (IPG) under the skin of the chest. DBS allows direct testing of neurobiologically-guided hypotheses regarding the etiology of substance use disorders in service of developing more effective treatments. Early studies, although with multiple limitations, have been promising. Still the authors express caution regarding implementation of DBS studies in this population and emphasize the importance of safeguards to ensure patient safety and meaningful study results. In this perspectives article, we review lessons learned through the years of planning an ongoing trial of DBS for methamphetamine use disorder. [ABSTRACT FROM AUTHOR]

In healthy individuals, regulatory T cells (Tregs) suppress self-reactive lymphocytes to prevent autoimmune disease; however, in cancer patients, Tregs also serve a protumorigenic function, as their presence in the tumor microenvironment interferes with the ability of other lymphocytes to target and eliminate cancer cells. Because the progression of cancer is largely determined by the interactions between particular lymphocytes and cancer cells, higher concentrations of Tregs correspond with shorter lifespans among cancer patients after diagnosis. Evidence shows that the removal of Tregs can enhance the anti-tumor immune response. Moreover, the depletion of Tregs is even considered an effective cancer immunotherapy treatment strategy for certain cancers. Other forms of treatment include exercise, which has been reported to reduce the risk of cancer recurrence and mortality, as well as regulate and deter the growth of tumors. Because of the effects reported from these treatment methods, the notion that exercise indirectly combats cancer by influencing specific lymphocytes became an idea of interest. This research is concerned with the effect of exercise on regulatory T cell populations in the tumors and spleens of tumor-bearing rats. It was hypothesized that exercise decreases the proliferation of Treg cells in the tumor microenvironment and lymphoid tissue. For this study, tumor and spleen samples were collected from sedentary and exercised cohorts of rats with breast cancer. Subsequently, CD25 antibody, Foxp3 antibody, and Hoechst dye were applied to the tissues so that samples could be visualized using fluorescence microscopy to identify Tregs. Overall trends in the data suggest that exercise reduces Treg cell count in both the tumors and spleens of individuals, thereby limiting the extent to which Tregs can suppress the anti-tumor immune response in cancer patients. Implementing a larger sample size, CD24 antibodies, confocal microscopy, and flow cytometry in future studies would enable stronger conclusions to be drawn in regards to the effect of exercise on Treg populations in cancer patients. Further examination of the interactions between cancerous cells and various lymphocytes may greatly contribute to the development of more efficacious cancer treatment strategies in the future. [ABSTRACT FROM AUTHOR]