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Objective@#The aim of this study was to describe the distribution of neck-shoulder symptoms among middle school students, and to explore its influence factors.@*Methods@#A cross-sectional survey was conducted on 24 middle schools in Shenyang, Zhengzhou and Shenzhen by purposive sampling method. In each middle school, 3 to 4 classes were selected from each grade all the students in the selected class would be recruited to the survey to investigate the demographic characteristics, neck-shoulder symptoms, physical exercise time, academic stress, screen behavior, sedentary behavior and other information by questionnaire. A total of 10 566 questionnaires were issued and 10 270 valid questionnaires were withdrawn. The prevalence of neck-shoulder symptoms among students were compared by different characteristics. Logistic regression models were applied to examine influencing factors associated with neck-shoulder symptoms.@*Results@#The prevalence of neck-shoulder symptoms among middle school students was 19.2% (1 968/10 270), while it was 22.6% (1 137/5 039) among girls and 15.9% (831/5 231) among boys; the difference showed statistical significance (P<0.001). The prevalence of neck-shoulder symptoms was separately 13.3% (253/1 901) in seventh grade, 16.8% (326/1 942) in eighth grade, 18.5% (299/1 617) in ninth grade, 21.8% (417/1 915) in sophomore, 21.4% (345/1 611) in junior, 25.5% (328/1 284) in senior; the difference showed statistical significance (P<0.001). The multivariate logistic regression analysis showed that in the last 3 months, students who always playing mobile phone ≥40 min continuously (OR=4.66, 95%CI: 3.95-5.49), watching TV ≥40 min continuously (OR=4.01, 95%CI: 3.39-4.73), using computer ≥40 min continuously (OR=3.61, 95%CI: 3.09-4.23), doing homework ≥60 min continuously (OR=3.25, 95%CI: 2.79-3.79), the average daily sitting time ≥10 h (OR=4.95, 95%CI: 4.25-5.77), and always sitting ≥90 min continuously (OR=5.18, 95%CI: 4.42-6.06) were risk factors of neck-shoulder symptoms.@*Conclusion@#The prevalence of neck-shoulder symptoms was high among middle school students in China, especially girls in senior grades. Long time, high frequency video behaviors and sedentary behaviors were related to the occurrence of neck-shoulder symptoms among middle school students.
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Objective To observe the concentration changes of plasma cortisol ( Cor ) and adrenocorticotropic hormone( ACTH) in preterm infants with respiratory failure receiving ventilation treatment. Methods The 30 preterm in-fants with respiratory failure requiring mechanical ventilation were selected as the preterm group with respiratory failure, and 32 full term infants with respiratory failure in need of mechanical ventilation were selected as the term infant group with respiratory failure, and 52 preterm infants( preterm control group) and 17 full term infants( term control group) were selected as controls. All the cases were chosen from Neonatal Intensive Care Unit of Anhui Province Children′s Hospital during January to December 2014. The levels of plasma Cor and ACTH were measured and analyzed. Results (1) Cor level:on the 3rd day, the level of plasma Cor in the preterm group with respiratory failure was lower than that in the term group with respiratory failure[262. 50(162. 00-332. 50) nmol/L vs 531. 00(244. 75-644. 00) nmol/L], and higher than those in the preterm control group[199. 50(49. 05-388. 95) nmol/L] and term control group[120. 00(43. 90-191. 00) nmol/L], the differences were statistically significant(all P<0. 05). On the 7th day, the level of plasma Cor in the preterm group with respiratory failure was lower than that in the term group with respiratory failure[128. 00(65. 85-244. 00) nmol/L vs 222. 00 (131. 50-377. 85) nmol/L], the difference was statistically significant(P<0. 05). (2) ACTH level:on the 3rd day, the level of ACTH in the preterm group with respiratory failure was higher than those in the other groups[38. 20(25. 18-76. 65) pmol/L vs 24. 60(19. 03-38. 20) pmol/L vs 22. 30(14. 40-40. 60) pmol/L vs 24. 20(13. 90-45. 65) pmol/L], the differences were statistically significant(P<0. 05). On the 7th day, the concentration of ACTH in the preterm group with respiratory failure was lower than those in the term group with respiratory failure[16. 55(12. 78-31. 80) pmol/L vs 29. 85(18. 23-54. 65) pmol/L], and there were statistical differences(P<0. 05). Conclusions The newborns with respiratory failure were in criti-cal stress, the level of plasma Cor in the preterm infants with respiratory failure was lower than that of the term infants with respiratory failure, while the level of ACTH in the former was higher than that in the latter. And when the stress disap-peared, both of the plasma Cor and ACTH recovered to the normal level.
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Aim To discover the change of synaptic plasticity by supplementing DHA during development period in rats. Method We divided Wistar rats into two groups: fish oil group and control group. The fish oil rats were supplemented with fish oil(5?10~3 ml?g-1 body weight) by gavage daily. The control rat was supplemented with NS of the same dose. 90 days later, each rat was hippocampus of anaesthetized and LTP and LTD were recorded at hippocampus of the same rat. Result Compared to the control group, DHA group presented an obvious increase in PS LTP, while no changes were found in EPSP LTP. On the other hand,DHA group demonstrated an obvious canceling effect on both EPSP and PS LTD. Conclusion There exist effects on synaptic plasticity after supplement with DHA. It may be one of the factors that DHA improves learning and memory.