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BackgroundWe aim to investigate the profile of acute antibody response in COVID-19 patients, and provide proposals for the usage of antibody test in clinical practice. MethodsA multi-center cross-section study (285 patients) and a single-center follow-up study (63 patients) were performed to investigate the feature of acute antibody response to SARS-CoV-2. A cohort of 52 COVID-19 suspects and 64 close contacts were enrolled to evaluate the potentiality of the antibody test. ResultsThe positive rate for IgG reached 100% around 20 days after symptoms onset. The median day of seroconversion for both lgG and IgM was 13 days after symptoms onset. Seroconversion of IgM occurred at the same time, or earlier, or later than that of IgG. IgG levels in 100% patients (19/19) entered a platform within 6 days after seroconversion. The criteria of IgG seroconversion and > 4-fold increase in the IgG titers in sequential samples together diagnosed 82.9% (34/41) of the patients. Antibody test aided to confirm 4 patients with COVID-19 from 52 suspects who failed to be confirmed by RT-PCR and 7 patients from 148 close contacts with negative RT-PCR. ConclusionIgM and IgG should be detected simultaneously at the early phase of infection. The serological diagnosis criterion of seroconversion or the >; 4-fold increase in the IgG titer is suitable for a majority of COVID-19 patients. Serologic test is helpful for the diagnosis of SARS-CoV-2 infection in suspects and close contacts.
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Objective: To study the regulatory mechanism of Nac-1 on the self-renewal of neural stem/progenitor cells (NSPCs). Methods: The expression level of Nac-1 was detected by using ESCs-derived NSPCs as the cell model. RNA interference was used to reduce the expression of Nac-1; the interference efficiency was detected by quantitative RT-PCR and Western blot. The proliferation and apoptosis of NSPCs were detected by cell counting and flow cytometry. Luciferase assay was used to detect the transcriptional regulation of Nac-1 on c-Myc. Results: Nac-1 was highly expressed in NSPCs, and its mRNA level decreased by 77% after differentiation. Compared with that in the control group, the mRNA level of Nac-1 in the NSPCs of the experimental group was significantly decreased, and the interference efficiency was 69% and 66%, respectively. NSPCs with Nac-1 knockdown showed slow proliferation, increased apoptosis and tended to differentiate, and the mRNA level of c-Myc decreased by 46% and 57% in two Nac-1 knockdown groups, respectively. Luciferase assay showed that the transcriptional activity of c-Myc promoter decreased by 24% and 36%, respectively, suggesting that Nac-1 could regulate the promoter activity of c-Myc gene. Conclusion: Nac-1 can promote the proliferation of NSPCs and inhibit their differentiation by regulating the transcription of c-Myc.
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OBJECTIVE@#To investigate the incidence and risk factors of delirium after spinal surgery in elderly patients.@*METHODS@#A retrospective analysis was performed on 436 patients with spinal surgery from January 2016 to November 2018. According to delirium occurrancy after the operation, 436 cases were divided into two groups:delirium group and non-delirium group. Body mass index(BMI), history of diabetes, history of coronary heart disease, history of chronic obstructive pulmonary disease (COPD), preoperative white blood cell count, preoperative erythrocyte volume, preoperative hemoglobin level, operation mode, operation time, anesthesia time, American Association of Anesthesiologists(ANA)(ASA) score, cardiac function grading(NYHA), intraoperative blood loss, intraoperative blood transfusion, intraoperative fentanyl, propofol and Dizocine dosage, postoperative white blood cell count, postoperative erythrocyte volume, postoperative hemoglobin level, postoperative electrolytes (sodium, potassium) and univariate logistic regression analysis were used to analyze the risk factors. The independent risk factors were further investigated by multivariate Logistic regression analysis.@*RESULTS@#Among 436 cases, 112 elderly patients had postoperative delirium, the incidence of delirium was about 25.68%. The age, preoperative leukocyte count, erythrocyte specific volume, postoperative hemoglobin level in delirium group and non-delirium group were measured. There were significant differences in the postoperative sodium concentration, anesthesia time, ASA score, cardiac function grading, blood loss during operation, postoperative use of Dizocine, history of diabetes, history of coronary heart disease and history of COPD (2, the use of Dizocine analgesic and the patients with COPD are the independent risk factors of postoperative delirium.
