To observe the dynamic change of parasites in the brains of BALB/c mice infected with Angiostrongylus cantonensis in order to explore its possible mechanism of pathogenesis', BALB/c mice infected with the III stage larvae of A.cantonensis were observed and killed in different times after infection. The number and distribution of parasites in the brains of the infected mice were observed microscopically and macroscopically. It was found that the larvae of A.cantonensis were distributed in the cerebrum and cerebellum of mice in accordance with the rule of parasitization of worms in the host, i.e.multiplication at first and then dropping in number. And the places where the parasites located were damaged due to mechanical action or inflammatory reactions. The time of onset of symptoms, such as ataxia and twitch was coincided with the dynamic changes in the brains of the infected mice.

Objective To study the effect of de novo donor-specific antigen (DSA) on transplant heart function and recipient survival after heart transplantation.Methods 195 recipients went through heart transplantion from March 2013 to January 2016 in our center,13 patients with preoperative panel reactive antibody (PRA) and 10 patients suffered from in-hospital death were exclude from this study,and the actual number of patients enrolled in this study was 172.By detecting HLA typing and DSA,recipients were divided into DSA positive group,anti-HLA antigen positive but DSA negative group (DSA negative group) and anti-HLA negative group.Cardiac dysfunction,coronary heart disease and cardiovascular death were recorded as cardiac events during the follow-up period.By analyzing the cardiac events rate among 3 groups,the relationship between DSA and cardiac events was acknowledged.Results The mean follow-up period of all patients was (1.3 ± 0.8) years.Among 172 patients,6 were positive for DSA (3.4％).In the DSA positive group,66％ of DSA were directed at HLA Ⅱ,mainly against HLA-DQ,1 developed only anti-HLA I antibody,1 developed both anti-HLA Ⅰ and Ⅱ antibody.The median developing time of DSA was (256 ± 125) days,and the distribution was centralized in the first half year.84％ of patients in DSA positive group were witnessed cardiac events.One patient was diagnosed as coronary heart disease and received PCI at 145th days after DSA was developed.Four out of 6 patients experienced cardiac dysfunction with median developing time of (54 ± 13) days,and the cardiac function restored after treatment with immunosuppression modification,high-dose glucocorticoid and IVIG.In the DSA negative PRA positive group,the incidence of cardiac events was 13％.There was one cardiovascular death,and 2 cases of cardiac dysfunction.In the HLA antigen negative group,the incidence of cardiac events was 4％.Cox regression analysis revealed that DSA could be seen as an independent risk factor in leading to cardiac events and affecting mid-long term survival of recipients (P =0.02).Significant difference was observed in Kaplan-Meier analysis among 3 groups (P＜0.001).Conclusion DSA has strong impact on outcome after heart transplantation.Routine surveillance and appropriate treatment should be attached to DSA.