Ouabain stimulates activation of various signaling cascades such as protein kinase B (Akt) and Extracellular-signaling-regulated kinase 1/2 (ERK 1/2) in various cell lines. Retinoic acid (RA) is commonly used to induce neuroblastoma differentiation in cultures. Upon RA administration, human neuroblastoma cell line, SK-N-SH demonstrated neurite extensions, which is an indicator of neuronal cell differentiation. Here we report that ouabain-induced signaling is altered under the action of 1 μM RA in human neuroblastoma SK-N-SH cells. RA increased the expression of p110α subunit of phosphoinositide 3-kinase (PI3K), Akt and β1 subunit of Na+/K+-ATPase. Ouabain activated Akt and ERK 1/2 in differentiated SK-N-SH cells; this effect was not observed in non-differentiated SK-N-SH cells. Long-term incubation of non-differentiated SK-N-SH with 1 μM ouabain led to a decrease in the number of cells; this effect was reduced in differentiated SK-N-SH cells. Taken together, these results suggest that ouabain leads to cell death in neuroblastoma cells rather than neuronal cells due to the different response to ouabain manifested by activation of Akt and ERK 1/2. Highlights • RA increases the expression of p110α subunit of PI3K, Akt and β1 subunit of Na+/K+-ATPase• Ouabain induces activation of Akt and ERK 1/2 in differentiated SK-N-SH cells but not in non-differentiated cells• 1 μM ouabain leads to a decrease in the number of cells in non-differentiated SK-N-SH• Reduction of ouabain-induced cell death in differentiated SK-N-SH

Children’s fear of a car accident occurring to parents or themselves has been used as a concrete example to illustrate one of the symptoms of anxiety disorders such as separation anxiety and generalized anxiety. However, its usage across countries may be questionable where the prevalence of this specific type of injury differs. This cross-sectional study compares samples from seven diverse European countries (Bulgaria, Germany, Italy, Lithuania, Netherlands, Romania, Turkey) to see if an environmental exposure, car accident death rate per 100,000 people (country-wide from WHO data), is associated with children’s self-report of car accident fears. In this study, 6–11 year-old children were surveyed by a diagnostic instrument (Dominic Interactive) about several situations and asked if they believed they were similar to a fictional child depicted in said situations. Mothers were surveyed for additional sociodemographic information. Multivariable logistic regression was used to adjust for covariates including mother’s age, mother’s education, single parenting, and mother’s professional inactivity. We report a monotonic relationship between higher car accident death rates and the prevalence of children reporting fear of parent’s or own accident. Relative to a reference of 3.9 deaths per 100,000 people, children’s odds of reporting fear of parent’s accident ranged from 1.99 (95% CI 1.51–2.61) times to 4.84 (95% CI 3.68–6.37) times as the risk of death by car accident increased across countries. A similar result arose from fear of child’s own accident, with significant ORs ranging from 1.91 (95% CI 1.53–2.40) to 2.68 (95% CI 2.07–3.47) alongside increased death rates. Given that reporting of these fears accompanies correspondingly high accident death rates, the pertinence of using fear of car accidents as an illustration for some diagnostic item for mental disorders cross-nationally appears to be an issue.

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