Screen Time and Body Mass Index Among Children and Adolescents: A Systematic Review and Meta-Analysis.

Background: There is no summative quantitative study that report the difference in BMI in high screen user children and adolescents or give a difference in screen time in children and adolescents with obesity vs. children and adolescents without obesity. In the current meta-analysis we systematically summarized the association between obesity and screen time and meta-analyzed the results. Methods: A systematic search from Scopus, PubMed and Embase electronic databases. Studies that evaluated the association between screen time and obesity up to June 2021. Results: Results revealed that those at the highest screen time category had 0.7 kg/m2 higher BMI (WMD = 0.703; CI = 0.128, 1.278; P < 0.016; I 2 = 95.8%). Moreover, children and adolescents with obesity had a mean value of 0.313 h higher screen time compared with children and adolescents without obesity (WMD: 0.313; OR = 0.219, 0.407; P < 0.001; I 2 = 96%). The results of subgrouping showed that study quality, continent and sample size could reduce the heterogeneity values. No evidence of publication bias was reported according to visual asymmetry of funnel plots and the results of Begg's and Egger's tests. Conclusion: For the first time, the current systematic review and meta-analysis revealed a positive association between screen time and obesity among children and adolescents. Due to the cross-sectional design of the included studies, causal inference is impossible, therefore, further studies in separate analysis of both genders are suggested to better elucidate gender-specific results. Systematic Review Registration: [www.ClinicalTrials.gov], identifier [CRD4202123 3899].

Modulation of astrocyte activity and improvement of oxidative stress through blockage of NO/NMDAR pathway improve posttraumatic stress disorder (PTSD)-like behavior induced by social isolation stress.

BACKGROUND: It has been well documented that social isolation stress (SIS) can induce posttraumatic stress disorder (PTSD)-like behavior in rodents, however, the underlying mechanism is remained misunderstood. In the current study, we aimed to elucidate the role of NO/NMDAR pathway in PTSD-like behavior through modulating of astrocyte activity and improvement of oxidative stress. METHODS: Male NMRI mice were used to evaluate the memory function by using Morris water maze (MWM) and fear memory extinction by using freezing response. We used MK-801 (NMDAR-antagonist), L-NNA (NOS-inhibitor), NMDA (NMDAR-agonist), and L-arginine (NO-agent) to find a proper treatment. Also, immunohistochemistry, RT-PCR, and oxidative stress assays were used to evaluate the levels of astrocytes and oxidative stress. We used five mice in each experimental task. RESULTS: Our results revealed that SIS could induce learning and memory dysfunction as well as impairment of fear memory extinction in MWM and freezing response tests, respectively. Also, we observed that combined treatment including blockage of NOS (by L-NNA, 0.5 mg/kg) and NMDAR (by MK-801, 0.001 mg/kg) at subeffective doses could result in improvement of both memory and fear memory. In addition, we observed that SIS significantly increases the GFAP expression and astrocyte activity, which results in significant imbalance in oxidative stress. Coadministration of MK-801 and L-NNA at subeffective doses not only decreases the expression of GFAP, but also regulates the oxidative stress imbalance CONCLUSION: Based on these results, it could be hypothesized that blockage of NO/NMDAR pathway might be a novel treatment for PTSD-like behavior in animals by inhibiting the astrocyte and regulating oxidative stress level.

Investigating the Role of Brain Lateralization and Gender in Paranormal Beliefs.

INTRODUCTION: Brain lateralization is associated with human behavior. Therefore, this study aimed at investigating the effects of brain lateralization on the scores of paranormal beliefs. METHODS: The study population included 180 students of Sanandaj universities, Sanandaj City, Iran who were selected with convenience sampling method (100 left-brained males, 6 left-brained females, 56 both left- and right-brained males and 22 both left- and right-brained females). The research tools were the paranormal belief scale developed by Blackmore (1994), as well as the brain lateralization questionnaire (1985). RESULTS: The obtained findings suggested a significant difference between the left-brain and right-brained people in terms of paranormal beliefs. A significant difference was also found between the left-brained males and both left- and right-brained females in terms of paranormal beliefs. CONCLUSION: The paranormal beliefs of the left-brained cases were different from both left- and right-brained subjects, which can be seen between the left-brained males and both left- and right-brained females.