Comparison of histological characteristics of two experimental mouse abdominal aortic aneurysm models / 西安交通大学学报(医学版)

【Objective】 To compare the histological characteristics of porcine pancreatic elastase （PPE） induced abdominal aortic aneurysms （AAA） and angiotensin Ⅱ （AngⅡ） induced AAA in mice. 【Methods】 In the PPE group， the mouse abdominal aorta segment from the infrarenal abdominal aorta to the iliac artery was isolated and its branch arteries were ligated to avoid leakage during PPE perfusion. We perfused the isolated aorta segment with a PPE solution at a concentration of 1.5 U/mL for 5 min and then closed the abdominal cavity. The diameter of the abdominal aorta was measured before and 14 days after the surgery， and the perfusion segment of the arteries was collected at day 14 after the surgery. The histological characteristics of the aneurysm were analyzed and graded by histological and immunohistochemical methods. In the AngⅡ group， ten apolipoprotein E knockout mice were prepared， and AngⅡ [1 000 ng/(kg·min)] was infused with osmotic pumps for 28 days. The aorta was separated and the aneurysm aorta segment was analyzed. The wild type mice were used as normal health controls. 【Results】 In the PPE group， the diameter of the PPE perfused aorta segments increased and was significantly larger than the basal diameter ［（0.52±0.02） mm vs. （1.23±0.11） mm］ at day 14 after surgery. All the ten mice developed AAA after PPE application. The histological results showed typical pathological features of AAA in PPE perfused mice， such as elastic fiber breakage， smooth muscle exhaustion， and increased inflammation. Six of the ten mice developed aneurysms after AngⅡ infusion （6/10）. The aneurysms/dilatations were mostly in the suprarenal abdominal aorta， but also in the thoracic aorta and aortic arch. The histology analysis showed that the formation of arterial dissection was common after AngⅡ infusion， and the typical vascular “false lumen” was found. The breakage of elastic fibers， the exhaustion of smooth muscle damage， and the inflammatory response were not as typical as the PPE model in AngⅡ perfused animals. 【Conclusion】 The histological characteristics of PPE induced AAA are very typical and well present the inflammatory process in the development of aneurysm. The AngⅡ model is suitable for the study of aneurysms combined with aortic dissection. Both models have their own advantages and can complement each other.

Application of time series model in prediction of nosocomial infection for cancer patients / 中华传染病杂志

Objective:To investigate the applicability of time series model in predicting incidence of nosocomial infection in a cancer center in Shanghai, and to provide the references for early warning and prevention.Methods:The nosocomial infection data of inpatients of a tertiary oncology hospital in Shanghai from 2013 to 2018 were collected. The autoregressive integrated moving average (ARIMA) model and the exponential smoothing model were established by SPSS 22.0 expert modeler. The fitting predictions were compared between these two time series models to select the optimal one. The nosocomial infection data from January 2019 to June 2019 were used to test the predictive effect of the model.Results:A total of 379 477 cancer inpatients were studied, 3 170 of which acquired nosocomial infection and the incidence was 0.84% from 2013 to 2018. Additive Holt-Winters method exponential smoothing model was the better model with R2of 0.82. Using this model, the predicted value fitted well with observed value from January 2019 to June 2019, and the mean relative percentage error was 15.22%. Conclusion:Additive Holt-Winters method exponential smoothing model could be used to fit and predict the tendency of nosocomial infection among cancer patients, which can provide reference for surveillance of nosocomial infection in oncology hospitals.

Maximum entropy model versus remote sensing-based methods for extract-ing Oncomelania hupensis snail habitats / 中国血吸虫病防治杂志

Objective To explore the technique of maximum entropy model for extracting Oncomelania hupensis snail habi?tats in Poyang Lake zone. Methods The information of snail habitats and related environment factors collected in Poyang Lake zone were integrated to set up the maximum entropy based species model and generate snail habitats distribution map. Two Land?sat 7 ETM+remote sensing images of both wet and drought seasons in Poyang Lake zone were obtained,where the two indices of modified normalized difference water index(MNDWI)and normalized difference vegetation index(NDVI)were applied to ex?tract snail habitats. The ROC curve,sensitivities and specificities were applied to assess their results. Furthermore,the impor?tance of the variables for snail habitats was analyzed by using Jackknife approach. Results The evaluation results showed that the area under receiver operating characteristic curve(AUC)of testing data by the remote sensing?based method was only 0.56, and the sensitivity and specificity were 0.23 and 0.89 respectively. Nevertheless,those indices above?mentioned of maximum en?tropy model were 0.876,0.89 and 0.74 respectively. The main concentration of snail habitats in Poyang Lake zone covered the northeast part of Yongxiu County,northwest of Yugan County,southwest of Poyang County and middle of Xinjian County,and the elevation was the most important environment variable affecting the distribution of snails,and the next was land surface tem?perature(LST). Conclusions The maximum entropy model is more reliable and accurate than the remote sensing?based meth?od for the sake of extracting snail habitats,which has certain guiding significance for the relevant departments to carry out mea?sures to prevent and control high?risk snail habitats.

Endemic situation trend of schistosomiasis in Guichi District of Chizhou City，Anhui Province，1991-2011 / 中国血吸虫病防治杂志

@#Objective To understand the epidemical patterns of schistosomiasis in Guichi District of Chizhou City，Anhui Province，in order to provide the reference for schistosomiasis control. Methods The annual data of schistosomiasis endemic situation in Guichi District from 1991 to 2011 were collected. The descriptive analysis was first conducted to describe the changes of schistosomiasis in local residents and the status of Oncomelania hupensis. An autoregressive integrated moving average （ARIMA）model was applied to fit and predict the tendency of schistosomiasis incidence in this region. Results The humanmorbidity increased with the increasing of the areas with snail habitats（P < 0.05），and four peaks（in 1992，1995，2005，2008）were detected. The difference of the area with snails among different types of snail habitats was statistically significant（F = 256.79，P < 0.05）. ARIMA（1，1，1）was determined to be the optimal model for analyzing the morbidity of schistosomiasis，and the short⁃term forecast of the morbidity in Guichi District from 2012 to 2015 showed that the predicted values were 0.017%，0.007%，0.012%，and 0.010%，respectively. Conclusions The endemic situation of schistosomiasis in Guichi District is controlled relatively well in the past two decades. However，the surveillance in the lake and marshland regions should be strengthened continuously to prevent the rebounding of the schistosomiasis endemic situation.