摘要
Objective:To evaluate the long-term impact of three different outdoor activity intervention strategies on the prevalence of myopia among school-aged children in China.Methods:Cross-sectional data from the Refractive Error Study in Children (RESC) on the baseline prevalence of myopia and 10-year longitudinal data from the Guangzhou Twin Eye Study (GTES) on the baseline incidence of myopia were utilized.The effect size of outdoor activity intervention was derived from longitudinal data of the Guangzhou Outdoor Activity Longitudinal Study (GOALS). Three intervention strategies were proposed: intervention for children in grades 1 to 6 (Strategy A), intervention for children in grades 1 to 3 (Strategy B), and intervention for children from the last year of kindergarten to grade 3 (Strategy C). Outdoor activity interventions across all strategies included an extra 40 minutes of daily outdoor activity time.Simulated analyses assumed that the prevalence of myopia would decrease with declining incidence and increasing school grade, and the degree of myopia among highly myopic children would decrease with delayed myopia onset.This study was approved by the Ethics Committee of Zhongshan Ophthalmic Center (No.2006-5).Results:With prolonged intervention time, the overall prevalence of myopia in children showed a significant declining trend.After 5 years of implementation, Strategy A resulted in a decrease in myopia prevalence from 34.67% to 25.71%, which decreased to 24.89% after 10 years, with an average annual reduction of 0.98%.Strategies B and C had similar long-term effects, with myopia prevalence after 10 years being 26.00% and 26.20% respectively, with an average annual reductions of 0.87% and 0.85%.Strategy A yielded the greatest reduction in myopia severity, with a decrease of -5.94 D after 5 years and -5.88 D after 10 years in the initial 15-year-old highly myopic individuals.Strategy B followed with -6.08 D and -6.02 D after 5 and 10 years, respectively.Conclusions:Implementing intensified outdoor activity intervention among children in grades 1 to 6 may be the recommended strategy to reduce the overall prevalence of myopia in regions with high rates of myopia among school-aged children.
摘要
The protective effect of vitamin E and the change in activity of enzymes at hepatic injury by carbon tetrachloride(CCl_4) were studied with histochcmical methods. 60 rats were devided into three groups(A,B,C). The group A was untreated control; the animals of group B and C were injected(i. m.) with 0.9% NaCl 1 ml/100g or vitamin E 1 ml/100g body weight qd for 7 days respectively and then treated with 30% CCl_4 0.05ml/l00g by adding to the solution of NaCl or vitamin E from 8th to 14th days. On the 15th day, rats were sacrificed for histochemical study of the liver parenchyma. The results showed that the activity of SDH, G-6-Pase, ATPase, 5-NT or AcP in liver lobules of groups B and C animals were changed conspicuously after treatment with CCl_4. The quantitative histochemistry of SDH and G-6-Pase was also consistent with these results. The activity of SDH, G-6-Pase, ATPase and 5-NT were inhibited, but of AcP was elevated. As compared with those in the rats of group A, the changes however in group B appeared more obviously than those in group C. The results indicated that CCl_4 of the given dose induced acute damage in liver cells, while vitamin E had important protective effect against acute liver damag induced by CCl_4.
摘要
68 NIH Mice (24-25g) were divided into three groups. Group A was normal control, group B was treated with 54% alcohol in the beverages 0.25ml/per day, and group C was administrated 54% alcohol mixed with folic acid 0.25ml/per day. The histochemical reaction and ultrastructural changes in liver were observed. The reaction of glycogen (PAS reaction), Mg-ATPase SDH LDH G-6-Pasc and ACP was demonstrated respectively by Chayen's, Wachstein-Meisel, Lojda, Bancroft's method, and some procedures of these techniques were modified. The results showed that under the protection effect of acid folic, the regularities seemed to be present in the changes of the following histochemical reactions in the liver cells of the group C (treaded by acid folic) the PAS reaction and the activities of Mg-ATPase SDH LDH G-6-Pase were similar to the group A and apparently higher than that in group B. The activities of ACP were lower those in group B(P