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.

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 investigate the clinical and genetic features of early-onset Alzheimer's disease(EOAD)and the characteristics of pathogenic mutations in probands and their families.Methods:Clinical and genetic features of three EOAD probands and their family members China were analyzed and summarized.Peripheral blood of three probands and their relatives was collected and the genes were detected by second generation sequencing(Next Generation Sequencing, NGS). Pathogenic mutations carried by the probands were identified by whole exome sequencing and then verified by Sanger sequencing in the probands and their families.Furthermore, the clinical and genetic characteristics of EOAD were discussed.Results:The first case was familial EOAD, with the heterozygous mutation c. 851C>T(p.P284L)in exon 8 of PSEN1.The second was also a case of familial EOAD, involving the heterozygous deletion mutation c. 497_499del(p.Ile167del)in exon 6 of PSEN1.In the third proband, there was no family history and the c. 626G>A(G209E)mutation was found in exon 7 of the PSEN1 gene.All three patients had memory loss as their first symptom, accompanied by clinical manifestations of slow movement, abnormal gait, unclear speech, bladder and bowel incontinence, psychiatric and other symptoms.Conclusions:These mutations represent additional mutation types and clinical manifestations in EOAD patients.Examining the genetic characteristics of PSEN1 in EOAD may contribute to the understanding of the pathogenesis, genetic classification and clinical diagnosis of EOAD.

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 summarize and analyze the clinical data of Chinese patients with colony-stimulating factor 1 receptor (CSF1R)-related leukoencephalopathy, and clarify the phenotypic and genetic characteristics of Chinese patients.Methods:Medical history of patients with CSF1R-related leukoencephalopathy diagnosed from April 1, 2018 to January 31, 2021 in the department of neurology of 22 hospitals in China was collected, and scores of Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment Scale (MoCA), magnetic resonance severity scale were evaluated. Group comparison was performed between male and female patients.Results:A total of 62 patients were included, and the male-female ratio was 1∶1.95. The age of onset was (40.35±8.42) years. Cognitive impairment (82.3%, 51/62) and motor symptoms (77.4%,48/62) were the most common symptoms. The MMSE and MoCA scores were 18.79±7.16 and 13.96±7.23, respectively, and the scores of two scales in male patients (22.06±5.31 and 18.08±5.60) were significantly higher than those in females (15.53±7.41 , t=2.954, P=0.006; 10.15±6.26, t=3.328 , P=0.003). The most common radiographic feature was bilateral asymmetric white matter changes (100.0%), and the magnetic resonance imaging severity scale score was 27.42±11.40, while the white matter lesion score of females (22.94±8.39) was significantly higher than that of males (17.62±8.74 , t=-2.221, P<0.05). A total of 36 CSF1R gene mutations were found in this study, among which c.2381T>C/p.I794T was the hotspot mutation that carried by 17.9% (10/56) of the probands. Conclusions:The core phenotypic characteristics of CSF1R-related leukoencephalopathy in China are progressive motor and cognitive impairment, with bilateral asymmetrical white matter changes. In addition, there exist gender differences clinically, with severer cognitive impairment and imaging changes in female patients. Thirty-six CSF1R gene mutations were found in this study, and c.2381T>C/p. I794T was the hotspot mutation.

Background Some studies have found that exposure to heavy metals significantly increases the risk of nonalcoholic fatty liver disease (NAFLD), and welding operators in automobile manufacturing enterprises are exposed to heavy metals in the working environment. Objective To analyze the prevalence and related factors of NAFLD in workers of an automobile company in Guangzhou. Methods From January 1 of 2023 to December 31 of 2023, 5463 workers of an automobile company in Guangzhou who participated in the physical examination in the Occupational Health Surveillance Centre of Guangzhou Occupational Disease Prevention and Treatment Hospital were selected as research subjects. The general data, laboratory examinations, B-ultrasound examinations, and other data of the subjects were obtained through the physical examination system. The exposed occupational hazards were identified based on the workplace hazard surveillance report provided by the automotive company. Logistic regression was used to analyze potential influencing factors of NAFLD, and stratified analysis was used to adjust confounding factors according to the stepwise model to evaluate the relationship between exposure to manganese and its inorganic compounds and NAFLD. Results A total of 2129 cases (38.97%) were reported positive NAFLD. The results of logistic regression analysis showed that women had a lower risk of NAFLD (OR=0.40, 95%CI: 0.25, 0.64), while age > 25 years old (OR=1.49, 95%CI: 1.39, 1.60), body mass index (BMI) ≥24 kg·m⁻² (OR=7.54, 95%CI: 6.46, 8.79), and elevated alanine aminotransferase (ALT) (OR=4.87, 95%CI: 3.73, 6.36), γ-glutamyl transpeptidase (γ-GGT) (OR=1.54, 95%CI: 1.17, 2.02), triglyceride (TG) (OR=3.47, 95%CI: 2.92, 4.14), and fasting blood glucose (OR=1.70, 95%CI: 1.32, 2.20) associated with a higher risk of NAFLD. NAFLD was positive in 39.40% of heavy metal exposed workers (701/1779). NAFLD was positive in 45.19% of workers exposed to manganese and its inorganic compounds (169/374), and among workers over 34 years old, exposure to manganese and its inorganic compounds (OR=1.79, 95%CI: 1.07, 2.97) significantly increased the prevalence of NAFLD. Conclusion The association between heavy metal exposure and NAFLD in workers of an automobile enterprise in Guangzhou is not significant, but age and gender are related to the prevalence of NAFLD. BMI, ALT, γ-GGT, TG, and fasting blood glucose are positively correlated with the prevalence of NAFLD. Exposure to manganese and its inorganic compounds in welding workers of the automobile enterprise is associated with elevated risk of the disease, and the prevalence of NAFLD is significantly increased in workers over 34 years old.