Objective:To validate five-year risk prediction models for atherosclerotic cardiovascular di-sease (ASCVD) in a contemporary rural Northern Chinese population.Methods: Totally 6 489 rural adults aged 40 to 79 years without clinical ASCVD were enrolled at baseline between June and August 2010, and followed up through January 2017.Expected prediction risk using the China-PAR (prediction for ASCVD risk in China) model was compared with the pooled cohort equations (PCE) reported in the American College of Cardiology / American Heart Association guideline.Kaplan-Meier analysis was used to obtain the observed ASCVD event (including nonfatal myocardial infarction, coronary heart disease death, nonfatal or fatal stroke) rate at 5 years, and the expected-observed ratios were calculated to eva-luate overestimation or underestimation in the cohort.The participants in the cohort were divided into 4 categories (<5.0%, 5.0%-7.4%, 7.5%-9.9%, and ≥10.0%) for comparisons based on ASCVD prediction risk.The models were assessed by discrimination C statistic, calibration χ2, and calibration charts and plots for illustration as well.Results: Over an average 5.82 years of follow-up in this validation cohort with 6 489 rural Chinese participants, 955 subjects developed a first ASCVD event.Recalibrated China-PAR model overestimated ASCVD events by 22.2% in men and 33.1% in women, while the overestimations were much higher for recalibrated PCE as 67.3% in men and 53.1% in women.Gender-specific China-PAR model had C statistics of 0.696 (95%CI, 0.669-0.723) for men and 0.709 (95%CI, 0.690-0.728) for women, which were similar to those of 0.702 (95%CI, 0.675-0.730) for men and 0.714 (95%CI, 0.695-0.733) for women in the PCE.Calibration χ2 values in China-PAR were 17.2 and 54.2 for men and women, respectively;however, the PCE showed poorer ca-libration (χ2=192.0 for men and χ2=181.2 for women).In addition, the calibration charts and plots illustrated good agreement between the observations and the predictions only in the China-PAR model, especially for men.Conclusion: In this validation cohort of rural Northern Chinese adults, the China-PAR model had better performance of five-year ASCVD risk prediction than the PCE, indicating that recalibrated China-PAR model might be an appropriate tool for risk assessment and primary prevention of ASCVD in China.

Objective To explore the value of improved CT perfusion in delineation of brain arteriovenous malformation(AVM) target for stereotactic radiosurgery.Methods 22 patients diagnosed with AVM by DSA were included in this study.14 cases of AVM were detected from initial symptoms of intracereb.ral hemorrhage,of which 4 cases were given immediate intracranial hematoma evacuation,then in 3 cases postoperative embolization was performed,and other 10 cases received conservative treatment including 3 cases treated by embolization.8 cases of AVM were detected from initial symptoms of epilepsy or headache,without surgery or embolization treatment.In all patients,the improved CT perfusion and MRA examinations were performed before treatment to evaluate the diagnostic efficacy of different methods in AVM.Results The interference rates of hemorrhage and granulation tissue on MRA images were 27.3 ％ and 54.5 ％,respectively,while those on enhanced CT and improved CT perfusion images were 0 ％.The interference rate of embolization material on enhanced CT and improved CT perfusion images was 27.3％,while that on MRA images were 0％.The contrast-enhancement rates of MRA,CT and improved CT perfusion images were 4 5.5 ％,5 4.5 ％ and 7 2.7 ％,respectively.Conclusion Improved CT perfusion technique is helpful in delineation of brain AVM target for stereotactic radiosurgery in patients with AVM combined with intracerebral hemorrhage or postoperative patients.

Objective To investigate the toxic effect of the carboxyl-terminal peptide of β-amyloid precursor protein (APPC31) on Neuro2a cells as well as its role in the toxic process in Neuro2a cells induced by Aβ42 in vitro.Methods The plasmid vector and the APPC31 construct were transiently transfected into Neuro2a cells respectively by lipofectamine 2000.The viability of the cells was measured by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay at 48 h after transfection,and their morphocytology was observed by 4', 6-diamidino-2-phenylindole (DAPI) nucleus staining.Afterword different constructs including vector, WTAPP695, APP( D664A), the amino-terminal peptide of β-amyloid precursor protein (APP△C31) and APPC31 were transiently transfected into Neuro2a cells respectively via the same method.At 24 h after transfection Aβ42 was added into the culture medium of Neuro2a cells with the desired concentration for another 24 h for cell studies.The viabihty and morphocytology of the cells were measured by using the MTT assay and DAPI nucleus staining, respectively.Results When incubated in the absence of Aβ42, the viability of cells transfected with vector and APPC31construct were 0.81 ±0.10 and 0.88 ±0.12 respectively, and accordingly there was no significant difference between the these two groups (t = - 0.78, P = 0.48 ); meanwhile no obvious cell nuclear morphological changes of apoptosis or death occurred.However when incubated in the presence of Aβ42, the viability of cells transfected with vector, WTAPP695, APP( D664A), APP△C31 and APPC31 constructs were 0.82 ±0.01, 0.78 ±0.03, 0.55 ±0.04, 0.81 ±0.04, 0.78 ±0.02 and 0.54 ±0.02 respectively.The viability of cells transfected with WTAPP construct and APPC31 construct decreased significantly ( F = 47.53, P ＜0.05) compared with the control group, meanwhile cells displayed condensed nuclear and even nuclear fragmentation.Conclusions In vitro, over-expression of a certain level of APPC31 in Neuro2a cells fails in causing cell death, but this short peptide enhances cytotoxicity induced by Aβ42 in Neuro2a cells.Thus,these results provide the experimental basis for the further explication of the pathogenesis of Alzheimer's disease.