The clinical features and immune responses of asymptomatic individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have not been well described. We studied 37 ...asymptomatic individuals in the Wanzhou District who were diagnosed with RT-PCR-confirmed SARS-CoV-2 infections but without any relevant clinical symptoms in the preceding 14 d and during hospitalization. Asymptomatic individuals were admitted to the government-designated Wanzhou People's Hospital for centralized isolation in accordance with policy
. The median duration of viral shedding in the asymptomatic group was 19 d (interquartile range (IQR), 15-26 d). The asymptomatic group had a significantly longer duration of viral shedding than the symptomatic group (log-rank P = 0.028). The virus-specific IgG levels in the asymptomatic group (median S/CO, 3.4; IQR, 1.6-10.7) were significantly lower (P = 0.005) relative to the symptomatic group (median S/CO, 20.5; IQR, 5.8-38.2) in the acute phase. Of asymptomatic individuals, 93.3% (28/30) and 81.1% (30/37) had reduction in IgG and neutralizing antibody levels, respectively, during the early convalescent phase, as compared to 96.8% (30/31) and 62.2% (23/37) of symptomatic patients. Forty percent of asymptomatic individuals became seronegative and 12.9% of the symptomatic group became negative for IgG in the early convalescent phase. In addition, asymptomatic individuals exhibited lower levels of 18 pro- and anti-inflammatory cytokines. These data suggest that asymptomatic individuals had a weaker immune response to SARS-CoV-2 infection. The reduction in IgG and neutralizing antibody levels in the early convalescent phase might have implications for immunity strategy and serological surveys.
Abstract
Background
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel β-coronavirus, causes severe pneumonia and has spread throughout the globe rapidly. The disease associated ...with SARS-CoV-2 infection is named coronavirus disease 2019 (COVID-19). To date, real-time reverse-transcription polymerase chain reaction (RT-PCR) is the only test able to confirm this infection. However, the accuracy of RT-PCR depends on several factors; variations in these factors might significantly lower the sensitivity of detection.
Methods
In this study, we developed a peptide-based luminescent immunoassay that detected immunoglobulin (Ig)G and IgM. The assay cutoff value was determined by evaluating the sera from healthy and infected patients for pathogens other than SARS-CoV-2.
Results
To evaluate assay performance, we detected IgG and IgM in the sera from confirmed patients. The positive rate of IgG and IgM was 71.4% and 57.2%, respectively.
Conclusions
Therefore, combining our immunoassay with real-time RT-PCR might enhance the diagnostic accuracy of COVID-19.
A peptide-based magnetic chemiluminescence enzyme immunoassay for the detection of SARS-CoV-2 antibodies was developed; 71.4% (197 of 276) and 57.2% (158 of 276) of the COVID-19 inpatients were positive for IgG and IgM against SARS-CoV-2.
Tumor-infiltrating immune cells are present in various malignant tumors, but their clinical significance in gastric cancer (GC) remains unclear. This study aimed to investigate the prognostic ...significance of tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs).
Using a prospective database containing 401 cases of GC, we evaluated TIL (cluster of differentiation 8 (CD8) expression) and TAM (cluster of differentiation 68 (CD68) expression) statuses via immunohistochemical staining.
Compared with CD8+ TIL-negative cases (n = 196, 48.6%), CD8+ TIL-positive cases (n = 205, 51.1%) showed significantly better recurrence-free survival (RFS) log-rank p<0.001; multivariate HR: 0.372; 95% confidence interval (CI): 0.239-0.579, p<0.001. In contrast, compared with CD68+ TAM-negative cases (n = 217, 54.1%), CD68+ TAM-positive cases (n = 184, 45.9%) had significantly poor RFS log-rank p<0.001; multivariate HR: 2.182; 95% CI: 1.435-3.318, p<0.001. Thus, patients with a positive CD8+ TIL and negative CD68+ TAM status exhibited significantly increased RFS. Multivariate analysis demonstrated that CD8+ TILs and CD68+ TAMs may serve as independent prognostic markers for RFS. Incorporating CD8+ TIL and CD68+ TAM statuses into the AJCC TNM system generated a predictive model with better predictive accuracy for RFS. More importantly, patients with a positive TIL and negative TAM status showed a tendency of improved RFS after postoperative adjuvant chemotherapy (PAC). Similar results were obtained by overall survival (OS) analysis.
CD8+ TIL and CD68+ TAM statuses were identified as independent prognostic factors that may be integrated into the current TNM staging system to refine risk stratification and to better predict the survival benefit from PAC in patients with GC.
The current controlled trial was registered at ClinicalTrials.gov (ID: NCT02327481 ) on December 30, 2014.
Low‐cost Si‐based anode materials with excellent electrochemical lithium storage present attractive prospects for lithium‐ion batteries (LIBs). Herein, porous Si‐Cu3Si‐Cu microsphere@C composites are ...designed and prepared by means of an etching/electroless deposition and subsequent carbon coating. The composites show a core–shell structure, with a porous Si/Cu microsphere core surrounded by the N‐doped carbon shell. The Cu and Cu3Si nanoparticles are embedded inside porous silicon microspheres, forming the porous Si/Cu microsphere core. The microstructure and lithium storage performance of porous Si‐Cu3Si‐Cu microsphere@C composites can be effectively tuned by changing electroless deposition time. The Si‐Cu3Si‐Cu microsphere@C composite prepared with 12 min electroless deposition delivers a reversible capacity of 627 mAh g−1 after 200 cycles at 2 A g−1, showing an enhanced lithium storage ability. The superior lithium storage performance of the Si‐Cu3Si‐Cu microsphere@C composite can be ascribed to the improved electronic conductivity, enhanced mechanical stability, and better buffering against the large volume change in the repeated lithiation/delithiation processes.
Sharing a shell: Porous Si‐Cu3Si‐Cu microsphere@C core–shell composites fabricated by an etching/electroless deposition and subsequent carbon coating show excellent lithium storage performance.
Abstract
Background
Coronavirus disease 2019 (COVID-19) is a global pandemic with no licensed vaccine or specific antiviral agents for therapy. Little is known about the longitudinal dynamics of ...severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–specific neutralizing antibodies (NAbs) in patients with COVID-19.
Methods
Blood samples (n = 173) were collected from 30 patients with COVID-19 over a 3-month period after symptom onset and analyzed for SARS-CoV-2–specific NAbs using the lentiviral pseudotype assay, coincident with the levels of IgG and proinflammatory cytokines.
Results
SARS-CoV-2–specific NAb titers were low for the first 7–10 days after symptom onset and increased after 2–3 weeks. The median peak time for NAbs was 33 days (interquartile range IQR, 24–59 days) after symptom onset. NAb titers in 93.3% (28/30) of the patients declined gradually over the 3-month study period, with a median decrease of 34.8% (IQR, 19.6–42.4%). NAb titers increased over time in parallel with the rise in immunoglobulin G (IgG) antibody levels, correlating well at week 3 (r = 0.41, P < .05). The NAb titers also demonstrated a significant positive correlation with levels of plasma proinflammatory cytokines, including stem cell factor (SCF), TNF-related apoptosis-inducing ligand (TRAIL), and macrophage colony-stimulating factor (M-CSF).
Conclusions
These data provide useful information regarding dynamic changes in NAbs in patients with COVID-19 during the acute and convalescent phases.
In this paper, a novel, low-complexity motion vector processing algorithm at the decoder is proposed for motion-compensated frame interpolation or frame rate up-conversion. We address the problems of ...having broken edges and deformed structures in an interpolated frame by hierarchically refining motion vectors on different block sizes. Our method explicitly considers the reliability of each received motion vector and has the capability of preserving the structure information. This is achieved by analyzing the distribution of residual energies and effectively merging blocks that have unreliable motion vectors. The motion vector reliability information is also used as a prior knowledge in motion vector refinement using a constrained vector median filter to avoid choosing identical unreliable one. We also propose using chrominance information in our method. Experimental results show that the proposed scheme has better visual quality and is also robust, even in video sequences with complex scenes and fast motion.
The effectiveness of control measures to contain coronavirus disease 2019 (COVID-19) in Wanzhou, China was assessed. Epidemiological data were analyzed for 183 confirmed COVID-19 cases and their ...close contacts from five generations of transmission of severe acute respiratory syndrome coronavirus 2 throughout the entire COVID-19 outbreak in Wanzhou. Approximately 67.2% and 32.8% of cases were symptomatic and asymptomatic, respectively. Asymptomatic and presymptomatic transmission accounted for 75.9% of the total recorded transmission. The reproductive number was 1.64 (95% confidence interval: 1.16-2.40) for G1-to-G2 transmission, decreasing to 0.31-0.39 in later generations, concomitant with implementation of rigorous control measures. Substantially higher infection risk was associated with contact within 5 d after the infectors had been infected, frequent contact and ≥8 h of contact duration. The spread of COVID-19 was effectively controlled in Wanzhou by breaking the transmission chain through social distancing, extensive contact tracing, mass testing and strict quarantine of close contacts.
Background and Aims
The mechanism underlying HCC metastasis remains unclear, many oncogenes are known to regulate this process. However, the role of alternative splicing (AS) in pro‐metastatic HCC is ...poorly understood.
Approach and Results
By performing RNA sequencing on nine pairs of primary HCC tissues with extrahepatic metastasis (EHMH) and nine pairs of metastasis‐free HCC (MFH) tissues, we depicted the AS landscape in HCC and found a higher frequency of AS events in EHMH compared with MFH. Moreover, 28 differentially expressed splicing regulators were identified in EHMH compared with MFH. Among these, DEAD‐box RNA helicase 17 (DDX17) was significantly up‐regulated in EHMH and was strongly associated with patient outcome. Functional studies indicated that DDX17 knockout inhibited the degradation of the extracellular matrix, and diminished the invasive ability of HCC cells. A significant reduction in lung metastasis induced by DDX17 deficiency was also demonstrated in a diethylnitrosamine‐induced DDX17HKO mouse model. Mechanistically, high DDX17 induced intron 3 retention of PXN‐AS1 and produced a transcript (termed PXN‐AS1‐IR3). The transcript PXN‐AS1‐IR3 acted as an important promoter of HCC metastasis by inducing MYC transcription activation via recruiting the complex of testis expressed 10 and p300 to the MYC enhancer region, which led to transcriptional activation of several metastasis‐associated downstream genes. Finally, the PXN‐AS1‐IR3 level was significantly higher in serum and HCC tissues with extrahepatic metastasis.
Conclusions
DDX17 and PXN‐AS1‐IR3 act as important metastatic promoters by modulating MYC signaling, suggesting that DDX17 and PXN‐AS1‐IR3 may be potential prognostic markers for metastatic HCC.
PDF
