Stroke is an important cause for childhood disability and death.Its risk factors and pathophysiological processes have significant differences with the adult patients.The common risk factors for pediatric arterial ischemic stroke (AIS) include cerebral arteriopathy,cardiac diseases,blood system and metabolic diseases,infection,and genetic factors.The clinical manifestations of AIS are different because of the age,underlying cause,and location of stroke.After a full examination,some risk factors or precipitating factors can be identified in more than 90％ of children with AIS,and thus emphasizing the importance of comprehensive diagnosis and evaluation.Although a number of clinical guidelines for pediatric stroke have been published,its evidence base is rather weak.Therefore,the present treatment mainly bases upon the expert consensus and the conclusions from the adult stroke studies.This article reviews the epidemiology,risk factors,clinical evaluation,managment and outcome of pediatric AIS.

AIM:To explore the changes and significance of Kupffer cells in the process of tree shrew chroni -cally infected with hepatitis B virus (HBV).METHODS:The animals were divided into 3 groups.Group A consists of 6 tree shrews that were identified as persistently infected with HBV;group B consists of 3 tree shrews that were suspected as persistently infected with HBV;group C consists of 4 tree shrews that were not inoculated with HBV and were applied as normal controls.Liver biopsies were collected regularly from all animals , and the Kupffer cells were isolated , purified and primarily cultured.The techniques of flow cytometry , immunohistochemistry, lysosomal fluorescent probe staining and real-time RT-PCR were applied to determine the number and function of these Kupffer cells .RESULTS: The result showed that the count and proportion of CD 163+cells in group A were significantly higher than those in group B and group C ( P<0.05).Meanwhile, the fluorescence intensity levels of lysosomal , the number of lysozyme-positive cells and the mRNA ex-pression level of TNF-αin the Kupffer cells in group A were significantly lower than those in group B and group C ( P<0.05).CONCLUSION:Kupffer cells may play a regulatory role during host’s chronic HBV infection.