https://www.selleckchem.com/products/clozapine-n-oxide.html To assess changes in optic nerve sheath diameter (ONSD) at high altitude and in acute mountain sickness (AMS). Cochrane Library, EMBASE, Google Scholar and PubMed were searched for articles published from their inception to 31st of July 2020. Outcome measures were mean changes of ONSD at high altitude and difference in ONSD change between subjects with and without AMS. Meta-regressions were conducted to investigate the relation of ONSD change to altitude and time spent at that altitude. Eight studies with 248 participants comparing ONSD from sea level to high altitude, and five studies with 454 participants comparing subjects with or without AMS, were included. ONSD increased by 0.14 mm per 1000 m after adjustment for time (95% CI 0.10 to 0.18; p<0.01). Restricted cubic spline regression revealed an almost linear relation between ONSD change and time within 2 days. ONSD was greater in subjects with AMS (mean difference=0.47; 95% CI 0.14 to 0.80; p=0.01; I =89.4%). Our analysis shows that ONSD changes correlate with altitude and tend to increase in subjects with AMS. Small study number and high heterogeneity are the limitations of our study. Further large prospective studies are required to verify our findings. Our analysis shows that ONSD changes correlate with altitude and tend to increase in subjects with AMS. Small study number and high heterogeneity are the limitations of our study. Further large prospective studies are required to verify our findings. To examine (1) if tobacco retail outlets (TROs) closer to middle and high schools have more tobacco advertisements than TROs farther away and (2) the potential impact of two place-based tobacco control strategies on tobacco advertisements a simulated ban of TROs (1) within 1000ft of schools and (2) within 500 ft of other TROs. TROs within half-mile of 53 middle and high schools in the four largest Metropolitan areas in Texas were audited for all tobacco m