Quantitative determination of the electron beam radiation dose for SARS-CoV-2 inactivation to decontaminate frozen food packaging.

The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from cold-chain foods to frontline workers poses a serious public health threat during the current global pandemic. There is an urgent need to design concise approaches for effective virus inactivation under different physicochemical conditions to reduce the risk of contagion through viral contaminated surfaces of cold-chain foods. By employing a time course of electron beam exposure to a high titer of SARS-CoV-2 at cold-chain temperatures, a radiation dose of 2 â€‹kGy was demonstrated to reduce the viral titer from 104.5 to 0 median tissue culture infectious dose (TCID50)/mL. Next, using human coronavirus OC43 (HCoV-OC43) as a suitable SARS-CoV-2 surrogate, 3 â€‹kGy of high-energy electron radiation was defined as the inactivation dose for a titer reduction of more than 4 log units on tested packaging materials. Furthermore, quantitative reverse transcription PCR (RT-qPCR) was used to test three viral genes, namely, E, N, and ORF1ab. There was a strong correlation between TCID50 and RT-qPCR for SARS-CoV-2 detection. However, RT-qPCR could not differentiate between the infectivity of the radiation-inactivated and nonirradiated control viruses. As the defined radiation dose for effective viral inactivation fell far below the upper safe dose limit for food processing, our results provide a basis for designing radiation-based approaches for the decontamination of SARS-CoV-2 in frozen food products. We further demonstrate that cell-based virus assays are essential to evaluate the SARS-CoV-2 inactivation efficiency for the decontaminating strategies.

A Landscape Study on COVID-19 Immunity at the Single-Cell Level.

Since 2019, the coronavirus (COVID-19) has outbroken continuously, spreading internationally and threatening the public health. However, it was unknown how the disorder at the single-cell level was associated with the pathogenesis of COVID-19. This study presented the disorders of macrophages, epithelial cells, CD8+ T cells, and natural killer (NK) cells at the single-cell level in the courses of COVID-19 and analyzed the immune response to cytokine storm. Compared with the healthy group, patients with COVID-19 had higher proportions of macrophages and lower proportions of T and NK cells, especially proportions of macrophages and epithelial cells with an increase during patients' conditions from mild to severe. This study suggested that there were high levels of pro-inflammatory and chemokine expressions in cells of COVID-19 and analyzed cell subsets to explore its changes and pathways. It was worth noting that several subsets of macrophages, epithelial cells, CD8 T cells, and NK cells were involved in inflammation pathways, including interleukin-17 (IL-17) signaling pathway and tumor necrosis factor (TNF) signaling pathway. Moreover, the pathways interacting COVID-19 and cytokine receptor with each other were remarkably enriched. In addition, these cell subsets played important roles in inflammation, and their abnormal functions may cause COVID-19. In conclusion, this study provided an immune outlook for COVID-19 at the single-cell level and revealed different pathways in immune response of COVID-19 single cells.

Bisphenol chemicals disturb intestinal homeostasis via Notch/Wnt signaling and induce mucosal barrier dysregulation and inflammation.

Emerging evidence has shown that bisphenol A (BPA) can exert adverse effects on intestinal barrier in rodents, but little is known about its underlying mechanisms. We previously found BPA and its substitute bisphenol F (BPF) disrupted Notch signaling and altered intestinal histological structures in Xenopus laevis tadpoles. The present study aimed to determine whether BPA and BPF could affect intestinal homeostasis via Notch/Wnt signaling and induce intestinal barrier dysregulation in adult mammals, given the fundamental roles of the two conserved signaling pathways in intestinal homeostasis and regulation of intestinal barrier. We found that following 7-day administration with BPA or BPF through drinking water at the reference dose of 50 µg/kg/d and no observed adverse effect level of 5 mg/kg/d (NOAEL) of BPA, adult male mice displayed no alterations at histological and cellular levels in colons, but high dose of both BPA and BPF downregulated the expression of Notch- and Wnt-related genes as well as key genes responsible for intestinal homeostasis. When administration was extended to 14 days, all treatments significantly suppressed the expression of all tested Notch- and Wnt-related genes; correspondingly, administrated colons exhibited downregulated expression of key genes responsible for intestinal homeostasis and reduced cell proliferation in crypts. Importantly, all treatments suppressed secretory cell differentiation, reduced mucin protein levels and downregulated expression of tight junction markers, implicating mucosal barrier dysregulation. Furthermore, inflammatory cell infiltration and upregulated expression of inflammatory cytokine genes in colons, coupled with increased serum inflammatory cytokine levels, were observed in all treatments. All results show that both BPA and BPF at the reference dose disrupted Notch/Wnt signaling and intestinal homeostasis, thereby leading to mucosal barrier dysregulation and intestinal inflammation in mice. This is the first study revealing the adverse influences of BPF on mammal intestines and underlying mechanisms for bisphenol-caused intestinal injury.

Plasma gp96 is a Novel Predictive Biomarker for Severe COVID-19.

Early and effective identification of severe coronavirus disease 2019 (COVID-19) may allow us to improve the outcomes of associated severe acute respiratory illness with fever and respiratory symptoms. This study analyzed plasma concentrations of heat shock protein gp96 in nonsevere (including mild and typical) and severe (including severe and critical) patients with COVID-19 to evaluate its potential as a predictive and prognostic biomarker for disease severity. Plasma gp96 levels that were positively correlated with interleukin-6 (IL-6) levels were significantly elevated in COVID-19 patients admitted to the hospital but not in non-COVID-19 patients with less severe respiratory impairment. Meanwhile, significantly higher gp96 levels were observed in severe than nonsevere patients. Moreover, the continuous decline of plasma gp96 levels predicted disease remission and recovery, whereas its persistently high levels indicated poor prognosis in COVID-19 patients during hospitalization. Finally, monocytes were identified as the major IL-6 producers under exogenous gp96 stimulation. Our results demonstrate that plasma gp96 may be a useful predictive and prognostic biomarker for disease severity and outcome of COVID-19. IMPORTANCE Early and effective identification of severe COVID-19 may allow us to improve the outcomes of associated severe acute respiratory illness with fever and respiratory symptoms. Some heat shock proteins (Hsps) are released during oxidative stress, cytotoxic injury, and viral infection and behave as danger-associated molecular patterns (DAMPs). This study analyzed plasma concentrations of Hsp gp96 in nonsevere and severe patients with COVID-19. Significantly higher plasma gp96 levels were observed in severe than those in nonsevere patients, and its persistently high levels indicated poor prognosis in COVID-19 patients. The results demonstrate that plasma gp96 may be a useful predictive and prognostic biomarker for disease severity and outcome of COVID-19.

Tocilizumab treatment for COVID-19 patients: a systematic review and meta-analysis.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has killed over 2.5 million people worldwide, but effective care and therapy have yet to be discovered. We conducted this analysis to better understand tocilizumab treatment for COVID-19 patients. MAIN TEXT: We searched major databases for manuscripts reporting the effects of tocilizumab on COVID-19 patients. A total of 25 publications were analyzed with Revman 5.3 and R for the meta-analysis. Significant better clinical outcomes were found in the tocilizumab treatment group when compared to the standard care group [odds ratio (OR) = 0.70, 95% confidential interval (C): 0.54-0.90, P = 0.007]. Tocilizumab treatment showed a stronger correlation with good prognosis among COVID-19 patients that needed mechanical ventilation (OR = 0.59, 95% CI, 0.37-0.93, P = 0.02). Among stratified analyses, reduction of overall mortality correlates with tocilizumab treatment in patients less than 65 years old (OR = 0.68, 95% CI: 0.60-0.77, P < 0.00001), and with intensive care unit patients (OR = 0.62, 95% CI: 0.55-0.70, P < 0.00001). Pooled estimates of hazard ratio showed that tocilizumab treatment predicts better overall survival in COVID-19 patients (HR = 0.45, 95% CI: 0.24-0.84, P = 0.01), especially in severe cases (HR = 0.58, 95% CI 0.49-0.68, P < 0.00001). CONCLUSIONS: Our study shows that tocilizumab treatment is associated with a lower risk of mortality and mechanical ventilation requirement among COVID-19 patients. Tocilizumab may have substantial effectiveness in reducing mortality among COVID-19 patients, especially among critical cases. This systematic review provides an up-to-date evidence of potential therapeutic role of tocilizumab in COVID-19 management.

Identification of Potential Early Diagnostic Biomarkers of Sepsis.

OBJECTIVE: The goal of this article was to identify potential biomarkers for early diagnosis of sepsis in order to improve their survival. METHODS: We analyzed differential gene expression between adult sepsis patients and controls in the GSE54514 dataset. Coexpression analysis was used to cluster coexpression modules, and enrichment analysis was performed on module genes. We also analyzed differential gene expression between neonatal sepsis patients and controls in the GSE25504 dataset, and we identified the subset of differentially expressed genes (DEGs) common to neonates and adults. All samples in the GSE54514 dataset were randomly divided into training and validation sets, and diagnostic signatures were constructed using least absolute shrink and selection operator (LASSO) regression. The key gene signature was screened for diagnostic value based on area under the receiver operating characteristic curve (AUC). STEM software identified dysregulated genes associated with sepsis-associated mortality. The ssGSEA method was used to quantify differences in immune cell infiltration between sepsis and control samples. RESULTS: A total of 6316 DEGs in GSE54514 were obtained spanning 10 modules. Module genes were mainly enriched in immune and metabolic responses. Screening 51 genes from among common genes based on AUC > 0.7 led to a LASSO model for the training set. We obtained a 25-gene signature, which we validated in the validation set and in the GSE25504 dataset. Among the signature genes, SLC2A6, C1ORF55, DUSP5 and RHOB were recognized as key genes (AUC > 0.75) in both the GSE54514 and GSE25504 datasets. SLC2A6 was identified by STEM as associated with sepsis-associated mortality and showed the strongest positive correlation with infiltration levels of Th1 cells. CONCLUSION: In summary, our four key genes may have important implications for the early diagnosis of sepsis patients. In particular, SLC2A6 may be a critical biomarker for predicting survival in sepsis.

Comprehensive Identification of Key Genes Involved in Development of Diabetes Mellitus-Related Atherogenesis Using Weighted Gene Correlation Network Analysis.

Coronary heart disease (CHD) is common in patients with diabetes mellitus (DM), however, the relevant mechanism remains elusive. The whole blood gene expression profiles of healthy control, patients with DM, patients with DM and CHD (DMCHD) were used to performed weight gene correlation network analysis (WGCNA) to identify the gene modules associated with DM-related atherogenesis. The candidate module was significantly involved in immune- and T cell activity-related biological process. GSEA results suggested that lysosome and apoptosis were enriched in DM and DMCHD samples. The protein-protein-KEGG pathway network may reveal the potential transcriptional regulatory network involving in DM-related atherosclerosis. Nineteen genes (RTKN, DCP1B, PDZD4, CACNA2D2, TSEN54, PVRIG, PLEKHF1, NKG7, ZAP70, NUDCD3, SLAMF6, CCDC107, NAG6, ZDHHC14, EOMES, VIL2, WDR54, DMAP1, and PMPCA) were considered as DM-related atherogenesis genes (DRAGs). The Gene Set Variation Analysis (GSVA) score of the DRAG set gradually increased in the control, DM and DMCHD. ROC curve analysis showed that ZAP70, TSEN54, and PLEKHF1 may be potential blood circulation biomarkers for DMCHD in patients with DM. In conclusion, we identified nineteen hallmark genes involving in DM-related atherogenesis and constructed a potential transcriptional regulatory network involving in DM-related atherosclerosis.

Bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers in wild frogs.

To investigate bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers (PBDEs) in amphibians, we collected adult frogs (Rana limnocharis) from a rice field in an e-waste recycling site in China. We found that ∑PBDEs in the whole frogs and various tissues (brain, liver, testis and egg) ranged from 17.10 to 141.11 ng g(-1) wet weight. Various tissues exhibited a similar PBDE congener profile, which was characterized by intermediate brominated congeners (BDE-99 and BDE-153) as the largest contributors, with less lower brominated congeners (BDE-28 and BDE-47) and higher brominated congeners (BDE-209). The maternal transfer capacity of PBDEs declined with the increase in bromine numbers of PBDE congeners. We suggest that the bromine atom number (the molecular size, to some degree) might be a determining factor for the maternal transport of a PBDE congener rather than K(ow) (Octanol-Water partition coefficient), which expresses a compound's lipophilicity. ∑PBDEs concentrations in frogs decreased over time during a depuration period of 54 days when these wild frogs were brought to the lab from the e-waste recycling site. The half-life of ∑PBDEs was 35 days, with about 14 days for BDE-47, and 36 and 81 days for BDE-99 and BDE-153, respectively. The data shows that the elimination of PBDEs has no essential difference from aquatic and terrestrial species.

Thyroid disruption by technical decabromodiphenyl ether (DE-83R) at low concentrations in Xenopus laevis.

Decabromodiphenyl ether (decaBDE), as a flame retardant, is widely produced and used. To study the thyroid disruption by technical decaBDE at low concentrations, Xenopus laevis tadpoles were exposed to technical decaBDE mixture DE-83R (1-1000 ng/L) in water from stage 46/47 (free swimming larvae, system of Nieuwkoop and Faber) to stage 62. DE-83R at concentration of 1000 ng/L significantly delayed the time to metamorphosis (presented by forelimb emergence, FLE). Histological examination showed that DE-83R at all tested concentrations caused histological alterations - multilayer follicular epithelial cell and markedly increased follicle size accompanied by partial colloid depletion and increase in the peripheral colloid vacuolation, in thyroid glands. All tested concentrations of DE-83R also induced a down-regulation of thyroid receptor mRNA expression. These results demonstrated that technical decaBDE disrupted the thyroid system in X. laevis tadpoles. Analysis of polybrominated diphenyl ethers (PBDEs) (sum of 39 congeners) in X. laevis indicated that mean concentrations of total PBDEs in X. laevis exposed to 1, 10, 100, 1000 ng/L were 11.0, 128.1, 412.1, 1400.2 ng/g wet weight, respectively. Considering that PBDEs burden ofX. laevis tadpoles was close to PBDEs levels in amphibians as reported in previous studies, our study has raised new concerns for thyroid disruption in amphibians of technical decaBDE at environmentally relevant concentrations.

Determination of environmentally relevant exposure concentrations of polybrominated diphenyl ethers for in vitro toxicological studies.

Toxicological studies at environmentally relevant concentrations are essential for understanding ecotoxic and health risks of pollutants such as polybrominated diphenyl ethers (PBDEs). However, no information is available on what exposure levels of PBDEs in vitro studies are environmentally relevant. We exposed MCF-7, HepG2, H295R and PC12 cells to BDE-47, and measured BDE-47 concentrations in the cells after exposure. We also used the percentile method to summarize literature data on environmental exposure levels of biotic tissues to PBDEs. The exposure concentration that resulted in a BDE-47 burden in cells close to the 90th percentile of PBDEs levels in tissues was assigned as the upper limit for the environmentally relevant concentration. Exposure to 1nM BDE-47 resulted in PBDEs burdens in MCF-7, HepG2 and H295R cells close to the 90th percentile but PBDEs burdens in PC12 cells were higher than the 90th percentile. In consideration of the high exposure levels in PBDE-polluted areas, we concluded that the highest environmentally relevant exposure concentration of PBDEs in culture media should be approximately 10nM for MCF-7, HepG2 and H295R cells, and<10nM for PC12 cells. These results provide an approximate reference for setting environmentally relevant exposure concentrations of PBDEs for studies in vitro.