Objective To evaluate the the protectice effect of dexmedetomidine combined limb remote ischemic postcondition on alleviating focal cerebral ischemic reperfusion injury in rats .Methods 48 healthy adult male SD rats were randomly divided into 4 groups(n= 12) :control group(C) ,limb remote ischemic postcondition group(R) and dexmedetomidine postconditioning group(D) and combination group(R/D) .The rat model of focal cerebral ischemic reperfusion injury was induced by middle cerebral artery oc‐clusion(MCAO) .The group C only received MCAO ,the left femoral artery was isolated without blocking ;the group R received 120 min brain ischemia ,the left femoral artery was occluded by 3 cycles of 10 min occlusion/10 min reperfusion before brain reperfu‐sion ;the group D received dexmedetomidine 3 μg/kg by intraperitoneal injection before brain reperfusion .The group R/D combined the above two kinds of processing method .The neurologic function was evaluated at 24 h of reperfusion and then the rats were sac‐rificed at 48 h of reperfusion .The brain was removed for determining the cerebral infarct volume .Results The neurologic function scores after 24 h reperfusion in the group D ,R and R/D were superior to those in the group C (P< 0 .01) .The rat cerebral infarct volume percentages after 48 h reperfusion in the group D ,R and R/D were significantly lower than those in the group C ( P <0 .01) .The infarct area volume percentage in the group R/D was significantly lower than that in the group R ,the difference showed statitistical significance(P< 0 .01) .The infarct volume percentage in group R/D was significantly decreased compared with the group D(P< 0 .05) .Conclusion Both dexmedetomidine and limb remote ischemic postcondition can attenuate the focal cerebral is‐chemic reperfusion injury in rats .Their combination can significantly reduce the cerebral infarction volume and has synergic protec‐tion effect .

Objective To assess the association between exposure to prenatal outdoor air pollution and preterm birth to provide evidence in setting up programs for prevention on premature birth.Methods Case-control studies regarding association between pregnant exposure to outdoor air pollution and preterm birth were collected.Data were analyzed with Stata 12.0.Results Ten articles including 48 556 cases and 548 495 controls were qualified for inclusion.Results from Meta-analyses showed pooled ORs for exposure to NO2,PM10,CO,PM2.5,and NO during the entire pregnancy were 0.960 (95％CI:0.935-0.985),1.068 (95％CI:1.035-1.103),1.122 (95％CI:1.078-1.168),1.110 (95％ CI:1.043-1.181) and 0.994 (95％ CI:0.973-1.016).Association between air pollution and preterm birth varied with the periods of exposure.Pooled ORs for NO2,PM10 and SO2 exposure during the first trimester were 1.117 (95％CI:1.052-1.186),0.968 (95％CI:0.812-1.153) and 1.258 (95％CI:0.758-2.089).Pooled ORs for NO2,PM10,SO2 exposure during the second trimester were 1.000 (95％ CI:0.982-1.019),1.127 (95％ CI:0.896-1.416) and 0.977 (95％CI:0.711-1.342).Pooled ORs for NO2,PM10,SO2 exposure during the third trimester were 1.006 (95％CI:1.002-1.010),1.053 (95％CI:0.973-1.139) and 1.003 (95％CI:1.000-1.006).Conclusion Exposures to PM10,CO and PM2.5 during the entire pregnancy,to NO2 during the first trimester,or to NO2 and SO2 during the third trimester were associated with preterm births.