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Objective@#To investigate the urine methyl tert-butyl ether (MTBE) level of a primary school students in Changping District, Beijing, and analysis the effect factors, give the advice if the MTBE is eligibility as an exposure biomarker of automobile exhaust.@*Methods@#Using the panel study, randomly selected 20 sixthgrade students (10 male and 10 female) from Zhixing School in Changping district, Beijing, from June 7th to 13th, 2018. All participants completed a questionnaire for collecting demographic and geographic information and daily activities. All participants were given guidance to repeatedly collected urine samples 3 times (8:00, 11:00 and 16:00 instant urien) a day for 7 days, totally 420 urine samples were collected. Urine MTBE were measured and the statistic significant of the Urine MTBE at different groups were evaluated.@*Results@#MTBE were detected in all 420 urine samples of primary school students, the geometric mean of creatinine-corrected MTBE exposure level in 8:00, 11:00 and 16:00 instant urine were 0.12, 0.12 and 0.12 mg/g creatinine, respectively. Urine MTBE concentration was statistical significant in different daily outdoor activity time, the distance of home address to the main road, and daily use time of air purification equipment in class(P=0.00, 0.04, 0.00).@*Conclusion@#There was a universal MTBE exposure among students in a primary school in Beijing, and the impact factors to exposure level were daily outdoor activity time, distance from home address to the closest main road, and daily use time of air purification equipment in class. This result indicate MTBE may be a valuable candidate for exposure biomarker of automobile exhaust, and more research should be done.
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Abstract: Introduction and aim. Hyponatremia is common in patients with decompensated cirrhosis and is associated with increased mortality. Tolvaptan, a vasopressor V2 receptor antagonist, can increase free wáter excretion, but its efficacy and safety in cirrhotic patients remain unclear. Material and methods. We studied the usage and safety of tolvaptan in cirrhotic patients in a real-life, non-randomized, multicenter prospective cohort study. Forty-nine cirrhotic patients with hyponatremia were treated with tolvaptan 15 mg daily, and 48 patients not treated with tolvaptan in the same period served as controls. Improvement in serum sodium level was defined as an increase in serum sodium from < 125 to ≥ 125 mmol/L or from 125-134 to ≥ 135 mmol/L on day 7. Results. Twenty-three (47%) patients in the tolvaptan group and 17 (35%) in the control group had normal serum sodium on day 7 (p = 0.25). Serum sodium improved in 30 (61%) patients in the tolvaptan group and 17 (35%) patients in the control group (p = 0.011). Adverse events occurred in 46-47% of patients in both groups, and tolvaptan was not associated with worsened liver function. No patient with normal serum sodium on day 7 died within 30 days of treatment, whereas 16% of those with persistent hyponatremia died (p = 0.0019). Conclusion. In conclusion, short-term tolvaptan treatment is safe and can improve serum sodium level in cirrhotic patients with hyponatremia. Normalization of serum sodium level is associated with better survival.