Effect of dexamethasone on intelligence and hearing in preterm infants: a meta-analysis

OBJECTIVE： A meta-analysis of published randomized controlled trials investigating the long- term effect of dexamethasone on the nervous system of preterm infants. DATA SOURCES： Online literature retrieval was conducted using The Cochrane Library （from January 1993 to June 2013）, EMBASE （from January 1980 to June 2013）, MEDLINE （from Janu- ary 1963 to June 2013）, OVID （from January 1993 to June 2013）, Springer （from January 1994 to June 2013） and Chinese Academic Journal Full-text Database （from January 1994 to June 2013）. Key words were preterm infants and dexamethasone in English and Chinese. STUDY SELECTION： Selected studies were randomized controlled trials assessing the effect of intravenous dexamethasone in preterm infants. The quality of the included papers was evaluated and those without the development of the nervous system and animal experiments were exclud- ed. Quality assessment was performed through bias risk evaluation in accordance with Cochrane Handbook 5.1.0 software in the Cochrane Collaboration. The homogeneous studies were analyzed and compared using Revman 5.2.6 software, and then effect model was selected and analyzed. Those papers failed to be included in the meta-analysis were subjected to descriptive analysis. MAIN OUTCOME MEASURES： Nervous system injury in preterm infants. RESULTS： Ten randomized controlled trials were screened, involving 1,038 subjects. Among them 512 cases received dexamethasone treatment while 526 cases served as placebo control group and blank control group. Meta-analysis results showed that the incidence of cerebral palsy, visual im- pairment and hearing loss in preterm infants after dexamethasone treatment within 7 days after birth was similar to that in the control group （RR = 1.47, 95%CI： 0.97-2.21; RR = 1.46, 95%CI： 0.97-2.20; RR = 0.80, 95%CI： 0.54-1.18; P 〉 0.05）, but intelligence quotient was significantly de- creased compared with the control group （MD = -3.55, 95%CI： -6.59 to -0.51; P = 0.02）. Prete rm infants treated with dexamethasone 7 days after birth demonstrated an incidence of cerebral palsy and visual impairment, and changes in intelligence quotient similar to those in the control group （RR = 1.26, 95%CI： 0.89-1.79; RR = 1.37, 95%CI： 0.73-2.59; RR = 0.53, 95%CI： 0.32-0.89; RR = 1.66, 95%CI： -4.7 to 8.01; P 〉 0.05）. However, the incidence of hearing loss was significantly increased compared with that in the control group （RR = 0.53, 95%CI： 0.32-0.89; P = 0.02）. CONCLUSION： Dexamethasone may affect the intelligence of preterm infants in the early stages after birth, but may lead to hearing impairment at later stages after birth. More reliable conclusions should be made through large-size, multi-center, well-designed randomized controlled trials.

Benefit Evaluation on the Control Mode for Typical Karst Rocky Desertification in Guizhou Province,China

Control mode for typical karst rocky desertification in Guizhou Province,China is selected as the research object.The ecological benefit,the social and economic benefit and the popularization prospect of mode are selected as evaluation indices.Evaluation index system of control modebenefits for karst rocky desertification is established.The Dingtan mode and the Wangjiazhai-Yangchangdong small watershed control mode are se-lected as evaluation objects.Preliminary assessment on the two modes are carried out by Analytic Hierarchy Process,grading evaluation,and com-prehensive evaluation method.Result shows that comprehensive score of Dingtan mode is 3.81,which is higher than the score of Wangjiazhai-Yangchangdong small watershed control mode(3.11).In the aspects of ecological benefit and social and economic benefit,Dingtan mode(4.83and 3.258) is superior than the Wangjiazhai-Yangchangdong small watershed control mode(3.38 and 2.531).In the aspect of popularization pros-pect of mode,score of Dingtan mode(3) is lower than that of Wangjiazhai-Yangchangdong small watershed control mode(3.333).Therefore,theevaluation index system has certain science and offers reference and guidance for the karst rocky desertification control in southwest China.

On emplacement ages of lam-proites in Zhenyuan County,Guizhou Province,China

Emplacement ages of lamproites that comprise lamproite and olivine lamproite in Zhenyuan County, Guizhou Province, China, have been constrained by the whole-rock Sm-Nd and Rb-Sr isochron methods and the whole rock K-Ar method. Intrusive activities of lamproites in the Sinantang area of Zhenyuan County, Guizhou Province, took place during the Late Cambrian, as indicated by the Sm-Nd isochron ages (t) = (503±17) (2σ) Ma and by the Rb-Sr isochron ages (t) = (501.2±4.6) (2σ) Ma. Intrusive activities of olivine lamproites at the Maping with Ⅱ -type diamond and Xitou in Zhenyuan County, Guizhou Province, took place from the Late Cambrian to the Early Ordovician, as evidenced by the Sm-Nd isochron ages (t) = (502±27) (2σ) Ma and by the Rb-Sr isochron age (t) = (502± 27) (2σ) Ma. This suggests that the upwelling hot materials derived from the deep mantle were emplaced from the Late Cambrian to the Early Ordovician (503-497 Ma), while the time terminal of cooling of the geothermal event of