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Painful diabetic neuropathy (PDN) is a long-term complication of diabetes. Defining symptoms include mechanical allodynia (pain due to light pressure or touch) and morphine hyposensitivity. In our previous work using the streptozotocin (STZ)-diabetic rat model of PDN, morphine hyposensitivity developed in a temporal manner with efficacy abolished at 3 months post-STZ and maintained for 6 months post-STZ. As this time course mimicked that for the temporal development of hyposensitivity to the pain-relieving effects of the furoxan nitric oxide (NO) donor, PRG150 (3-methylfuroxan-4-carbaldehyde) in STZ-diabetic rats, we hypothesized that progressive depletion of endogenous NO bioactivity may underpin the temporal loss of morphine sensitivity in STZ-diabetic rats. Furthermore, we hypothesized that replenishment of NO bioactivity may restore morphine sensitivity in these animals. Diabetes was induced in male Dark Agouti rats by intravenous injection of STZ (85 mg/kg). Diabetes was confirmed on day 7 if blood glucose concentrations were ≥15 mmol/L. Mechanical allodynia was fully developed in the bilateral hindpaws by 3 weeks of STZ-diabetes in rats and this was maintained for the study duration. Morphine hyposensitivity developed in a temporal manner with efficacy abolished by 3 months post-STZ. Administration of dietary l-arginine (NO precursor) at 1 g/d to STZ-diabetic rats according to a 15-week prevention protocol initiated at 9 weeks post-STZ prevented abolition of morphine efficacy. When given as an 8-week intervention protocol in rats where morphine efficacy was abolished, dietary l-arginine at 1 g/d progressively rescued morphine efficacy and potency. Our findings implicate NO depletion in the development of morphine hyposensitivity in STZ-diabetic rats., (© 2017 John Wiley & Sons Australia, Ltd.)

Background: Physical activity and nutrition behaviors are important to reducing the prevalence of childhood obesity. Previous research has identified school-based interventions as effective strategies to improve physical activity and nutrition. However, the results are often mixed, and middle schoolers are an under-studied population. Objective: Our study aims to fill this gap by developing an after-school intervention to increase physical activity and fruit and vegetable consumption that is influenced by national guidelines and formative research. Methods: This study was an after-school, quasi-experimental study spanning 9 months. Enrollment began in September 2021 and continued on a rolling basis through February 2022. Weekly, middle schoolers were offered 2-3 physical activity sessions and 1 produce kit. Physical activity was measured using accelerometers and questionnaires. Nutrition behaviors were assessed using questionnaires, and physical literacy was assessed using researcher observations. Follow-up data collection occurred in December 2021 and in April 2022. Difference scores will be calculated and analyzed for each outcome variable. Results: The intervention started in September 2021 and will conclude in May 2022. Published study results are expected in late 2022. Conclusions: An increase in physical literacy, physical activity, and fruit and vegetable consumption is expected. If successful, future studies will focus on reach and sustainability. Lastly, this study may serve as a model for improving health outcomes in middle schools. [ABSTRACT FROM AUTHOR]