ABSTRACT
【Objective】 To analyze the viability of 2 different blood screening strategies against SARS-CoV-2 in low risk populations, so as to provide references for the formulation of blood screening strategy. 【Methods】 Two screening strategies for antibodies against SARS-CoV-2 were adopted: 1) the total antibody were initially screened for all samples, and the antibody IgG and IgM were retested in those primary positive samples; 2) only antibody test of IgG and IgM for all samples. And SARS-CoV-2 nucleic acid was detected in parallel. Reactive samples was confirmed by neutralization test. The sensitivity, specificity and true positive rate of two strategies were calculated. 【Results】 None was positive for SARS-CoV-2 nucleic acid among 880 samples. Four truly positive samples were implicated in 9 (1.02%, 9/880) initially reactive samples in total antibody test; 3 in 26 (2.95%, 26/880) initially IgG or IgM reactive samples. 【Conclusion】 The first strategy is superior to the second strategy in the sensitivity and specificity, and is recommended for the detection of SARS-CoV-2 antibody in low risk populations.
ABSTRACT
ObjectivesThe prevalence of antibodies to SARS-CoV-2 among blood donors in China remains unknown. To reveal the missing information, we investigated the seroprevalence of SARS-CoV-2 antibodies among blood donors in the cities of Wuhan, Shenzhen, and Shijiazhuang of China. DesignCross-sectional study SettingThree blood centers, located in the central, south and north China, respectively, recruiting from January to April 2020. Participants38,144 healthy blood donors donated in Wuhan, Shenzhen and Shijiazhuang were enrolled, who were all met the criteria for blood donation during the COVID-19 pandemic in China. Main outcome measuresSpecific antibodies against SARS-CoV-2 including total antibody (TAb), IgG antibody against receptor-binding domain of spike protein (IgG-RBD) and nucleoprotein (IgG-N), and IgM. Pseudotype lentivirus-based neutralization test was performed on all TAb-positive samples. In addition, anonymous personal demographic information, including gender, age, ethnicity, occupation and educational level, and blood type were collected. ResultsA total of 519 samples from 410 donors were confirmed by neutralization tests. The SARS-CoV-2 seroprevalence among blood donors was 2.29% (407/17,794, 95%CI: 2.08% to 2.52%) in Wuhan, 0.029% (2/6,810, 95%CI: 0.0081% to 0.11%) in Shenzhen, and 0.0074% (1/13,540, 95%CI: 0.0013% to 0.042%) in Shijiazhuang, respectively. The earliest emergence of SARS-CoV-2 seropositivity in blood donors was identified on January 20, 2020 in Wuhan. The weekly prevalence of SARS-CoV-2 antibodies in Wuhans blood donors changed dynamically and were 0.08% (95%CI: 0.02% to 0.28%) during January 15 to 22 (before city lockdown), 3.08% (95%CI: 2.67% to 3.55%) during January 23 to April 7 (city quarantine period) and 2.33% (95%CI: 2.06% to 2.63%) during April 8 to 30 (after lockdown easing). Female and older-age were identified to be independent risk factors for SARS-CoV-2 seropositivity among donors in Wuhan. ConclusionsThe prevalence of antibodies to SARS-CoV-2 among blood donors in China was low, even in Wuhan city. According to our data, the earliest emergence of SARS-CoV-2 in Wuhans donors should not earlier than January, 2020. As most of the population of China remained uninfected during the early wave of COVID-19 pandemic, effective public health measures are still certainly required to block viral spread before a vaccine is widely available.
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Objective To explore the siqnificance of event related potential(ERP) N400 on stroke patients with aphasia and provide theoretical basis for clinical operations.Methods 29 stroke patients with aphasia(aphasia group) and 58 stroke patients without aphasia(control group) were selected,which were examined with N400.The latency and amplitude of N400 were compared between the two groups.Results The difference waves' latency and amplitude of aphasia group were longer and higher than those of control group.The difference had statistical significance (all P ＜ 0.05).Conclusion N400 is a significant marker for the language disturbance of aphasia patients.
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Objective To construct the recombinant rAAV2-hGAD65 vector and detect its function both in vitro and in vivo. Methods The cDNA of human glutamic acid decarboxylase 2 (hGAD65) gene, which was one of gamma-aminobutyric acid (GABA) synthetase, cloned by the method of RT-PCR, was subcloned into the adeno-associated virus (AAV) vector and formed the recombinant vector of AAV-hGAD65 (rAAV2-hGAD65). The recombinant vector was packaged by the AAV Helper-Free System and its titer was detected. The primary fibroblast, cultured from the rat lung, was transfected by the rAAV2-hGAD65. The expression of the hGAD65 in fibroblast was detected by immunohistochemical method and the level of GABA in the media was assayed by high performance liquid chromatograph (HPLC). In vivo, the hGAD65 was detected by immunohistochemical method in STN and the concentration of the GABA in the reticular part of substantia nigra (SNr) was assayed by HPLC after the rAAV2-hGAD65 was injected into the subthalamic nucleus (STN) by the stereotaxic method. Results The sequence of hGAD65 cDNA was in accordance with that in the Genebank. The amino acid sequence of hGAD65 had no mutation and the titer of rAAV2-hGAD65 was reached 4.5 ×10~(11) per milliliter. The efficiency of infection to the rat primary firoblasts was 80%, and the concentration of GABA in the media of fibroblasts was (45.66±6.07)nmol/L per liter. In vivo, hGAD65 could be detected in STN, and the concentrateion of the GABA in the SNr was increased from (5.66±1.07)nmol/g to (12.66±2.59)nmol/g.Conclusion The cDNA of hGAD65 was cloned by RT-PCR and the recombinant vector of rAAV2-hGAD65 was constructed. The AAV can infect the primary fibroblast in vitro and the hGAD65 can catalyse the glutamic acic to GABA. In vivo, the concentration of GABA in the SNr was heighten after the rAAV2-hGAD65 was injected into the STN.
ABSTRACT
The interlink,consistency and unity of all things is an important thought in traditional Chinese philosophy.Therefore,holism of human being and universe is the long-dominant thought in China.Traditional Chinese medicine(TCM)forms its theory based on this holism concept.From the perspect of history and philosophy,the difference between TCM and western medicine was discussed after retracting the influence of the holism of human being and universe on TCM.Holism of human being and universe has a profound impact on TCM,which also contributes to differences between TCM and western medicine.
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Objective To study the distribution of Nogo-A in the retina and the changes after the optic nerve(ON) injury in hamsters. Methods In this experiment,ON was crushed at 2?mm behind of the eyeball.After 3?d,5?d and 7?d post-axotomy,the Nogo antiserum immunoreactive staining on section of the retina was performed. Results Nogo was expressed at every layer of the retina with the strongest expression on 3?d post-axotomy.The numbers of Nogo-A positive RGCs decrease as the survived time increased.Conclusion Nogo-A in the retina is not unique secretion from the neuroglia.The change in the distribution and level of expressed of Nogo-A in the retina is correlated with time advancement after injured of ON.