Objective To construct a lentiviral vector delivering the Nicastrin (NCT) gene-targeted short hairpin RNA (shRNA) and determine gene-silencing efficiency of the vector in the human immortalized keratinocyte cell line HaCaT,and to construct a NCT gene-silenced HaCaT cell model to lay an experimental foundation for subsequently studying effects of NCT gene silencing on biological behavior of keratinocytes.Methods Three NCT gene-targeted shRNAs were designed and inserted into the pGLV3/ H1/GFP + Puro vector to construct three recombinant plasmids,which were then confirmed by sequencing.Recombinant plasmids combined with lentivirus packaging plasmids were co-transfected into 293T cells to obtain lentivirus particles,and the virus titer was determined.Cultured HaCaT cells were divided into 3 groups:blank group receiving no treatment,negative control group infected with the empty vector LV3-shNC,interference groups infected with lentivirus NCT-shRNA1,-shRNA2,-shRNA3,respectively.Flow cytometry was performed to determine transfection efficiency,and real-time fluorescence-based quantitative PCR (qRT-PCR) and Western blot analysis were conducted to determine efficiency of target gene silencing in HaCaT cells,so as to select the most efficient interference sequence.Results Sequencing analysis indicated that recombinant lentiviral vector NCT-shRNA was constructed successfully.After co-transfection of recombinant plasmids and lentivirus packaging plasmids into 293T cells,the titer of recombinant lentivirus particles was about 109 TU/ml.Flow cytometry showed that the transfection efficiency was greater than 95％.qRT-PCR revealed that the NCT mRNA expression was obviously down-regulated in the interference group compared with the negative control group,and NCT-shRNA1 was the most efficient sequence with interference efficiency being 75％.Western blot analysis showed that the inhibition rate of NCT protein expression was 71.7％ in the shRNA1 group compared with the negative control group.Conclusion The most efficient NCT-shRNA interference sequence is screened out,and the recombinant lentiviral vector NCT-shRNA and an NCT gene-silenced HaCaT cell model are both constructed successfully.

Adolescent ; Adult ; Bone Screws ; Child ; External Fixators ; Female ; Femoral Neck Fractures ; surgery ; Femoral Neoplasms ; complications ; surgery ; Hip Fractures ; surgery ; Humans ; Male

Objective To explore predictive factors of severe community-acquired pneumonia (CAP) complicated with respiratory failure (RF) and to develop and internally validate a clinical prediction model. Methods A retrospective study was conducted on 350 patients with severe CAP admitted to Tianyou Hospital Affiliated to Wuhan University of Science and Technology from September 2022 to December 2024. Patients were randomly divided into a training set (n＝245) and a validation set (n＝105) in a 7∶3 ratio, and further categorized into RF and non-RF groups. LASSO regression was applied to optimize variable selection. Multivariate logistic analysis was used to construct the prediction model, followed by internal validation. Results Univariate regression analysis identified male, hypertension, diabetes, coronary heart disease, age, CURB-65 score, white blood cell count, neutrophil count, C-reactive protein (CRP), serum amyloid A, procalcitonin, and hospital stay as risk factors for RF in severe CAP, while albumin level was a protective factor. LASSO regression selected CURB-65 score, albumin level, and CRP for inclusion in the final model. The area under the receiver operating characteristic curve was 0.903 in the training set and 0.919 in the validation set. Calibration curve analysis demonstrated excellent agreement between predicted and observed probabilities in both sets, and Hosmer-Lemeshow goodness-of-fit tests indicated no significant deviations. Threshold probabilities ranged from 0.01 to 0.99 in both training and validation sets. Conclusions CURB-65 score, albumin level, and CRP are independent predictors of RF in severe CAP. The clinical prediction model based on these factors exhibits strong discrimination, calibration, goodness-of-fit, and clinical utility.