Arsenic field test kits based on solid-phase fluorescence filter effect induced by silver nanoparticle formation.

Millions of people worldwide are affected by naturally occurring arsenic in groundwater. The development of a low-cost, highly sensitive, portable assay for rapid field detection of arsenic in water is important to identify areas for safe wells and to help prioritize testing. Herein, a novel paper-based fluorescence assay was developed for the on-site analysis of arsenic, which was constructed by the solid-phase fluorescence filter effect (SPFFE) of AsH3-induced the generation of silver nanoparticles (AgNPs) toward carbon dots. The proposed SPFFE-based assay achieves a low arsenic detection limit of 0.36 µg/L due to the efficient reduction of Ag+ by AsH3 and the high molar extinction coefficient of AgNPs. In conjunction with a smartphone and an integrated sample processing and sensing platform, field-sensitive detection of arsenic could be achieved. The accuracy of the portable assay was validated by successfully analyzing surface and groundwater samples, with no significant difference from the results obtained through mass spectrometry. Compared to other methods for arsenic analysis, this developed system offers excellent sensitivity, portability, and low cost. It holds promising potential for on-site analysis of arsenic in groundwater to identify safe well locations and quickly obtain output from the global map of groundwater arsenic.

Portable purge and trap-microplasma optical emission spectrometric device for field detection of iodine in water.

Iodine is essential for human growth and can enter the body through food, water, and air. Analyzing its presence in the environment is crucial for ensuring healthy human development. However, current large-scale instruments have limitations in the field analysis of iodine. Herein, a miniaturized purge and trap point discharge microplasma optical emission spectrometric (P&T-µPD-OES) device was developed for the field analysis of iodine in water. Volatile iodine molecules were produced from total inorganic iodine (TII) through a basic redox reaction under acidic conditions, then the purge and trap module effectively separated and preconcentrated iodine molecules. The iodine molecules were subsequently atomized and excited by the integrated point discharge microplasma and an iodine atomic emission line at 206.24 nm was monitored by the spectrometer. Under optimal conditions, this proposed method had a detection limit of 16.2 µg L-1 for iodine and a precision better than 4.8%. Besides, the accuracy of the portable device was validated by successful analysis of surface and groundwater samples and a comparison of the mass spectrometry method. This proposed portable, low-power device is expected to support rapid access to iodine levels and distribution in water.

Single cell multi-omics of fibrotic kidney reveal epigenetic regulation of antioxidation and apoptosis within proximal tubule.

BACKGROUND: Until now, there has been no particularly effective treatment for chronic kidney disease (CKD). Fibrosis is a common pathological change that exist in CKD. METHODS: To better understand the transcriptional dynamics in fibrotic kidney, we make use of single-nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq) and single-cell RNA sequencing (scRNA-seq) from GEO datasets and perform scRNA-seq of human biopsy to seek possible transcription factors (TFs) regulating target genes in the progress of kidney fibrosis across mouse and human kidneys. RESULTS: Our analysis has displayed chromatin accessibility, gene expression pattern and cell-cell communications at single-cell level in kidneys suffering from unilateral ureteral obstruction (UUO) or chronic interstitial nephritis (CIN). Using multimodal data, there exists epigenetic regulation producing less Sod1 and Sod2 mRNA within the proximal tubule which is hard to withstand oxidative stress during fibrosis. Meanwhile, a transcription factor Nfix promoting the apoptosis-related gene Ifi27 expression found by multimodal data was validated by an in vitro study. And the gene Ifi27 upregulated by in situ AAV injection within the kidney cortex aggravates kidney fibrosis. CONCLUSIONS: In conclusion, as we know oxidation and apoptosis are traumatic factors during fibrosis, thus enhancing antioxidation and inhibiting the Nfix-Ifi27 pathway to inhibit apoptosis could be a potential treatment for kidney fibrosis.

Urokinase-based lock solutions for catheter salvage: A case of an upcoming kidney transplant recipient.

Catheter-related bloodstream infection (CRBSI) is a significant complication among patients on haemodialysis (HD) who are dependent on a central venous catheter (CVC) for an extended period. Catheter removal as first-line treatment can induce accelerated venous access site depletion in patients on HD who rely on it to survive. It is possible to retain the catheter in stable patients without septic syndrome while administering systemic antibiotics and antibiotic lock therapy. Herein, we report the case of a patient on HD with CRBSI who was successfully treated with intravenous levofloxacin- and urokinase-based antibiotic lock, without catheter removal prior to kidney transplantation. The use of urokinase in combination with antibiotics in lock solutions for treating catheter infections is rare. We verified the physical compatibility of levofloxacin and urokinase by visual inspection, turbidimetric measurements, and particle count. To our knowledge, this was a rare case demonstrating the effective use of urokinase and levofloxacin in a catheter lock for CRBSI in a patient on HD. Considering the need for highly concentrated antimicrobials and the availability of various antibiotics, the compatibility and stability of the lock solution is a matter of concern. Further studies are warranted to assess the stability and compatibility of various antibiotics in combination with urokinase.

The impact of long-term exposure to ambient air pollution in patients undergoing peritoneal dialysis: A cohort study in China.

There is increasing evidence for an association of air pollutants and the incidence of chronic kidney disease, and the progression to end stage kidney disease (ESKD). Despite the global expansion of peritoneal dialysis (PD), the impact of environmental and climatic factors in PD patients has not been studied in detail. We aimed to assess the association of long-term residential exposure to air pollutants, with patient survival and incidence of hospitalizations. This was a cohort study of all prevalent ESKD patients who were stable on PD therapy for more than 90 days in our PD center from 2013/01/01 to 2018/12/31. The enrolled patients were followed until death, cessation of PD, loss to follow-up, or 2018/12/31. Time-varying pollutant exposures were modeled as the key time-dependent variables. We used time-dependent Cox model to evaluate the risk of mortality and hospitalizations associated with air pollutant exposures adjusted for potential confounders. A total of 886 subjects who meets inclusion criteria with 27,024 patient-months were modeled. Over a mean follow-up of 30.5 ± 21.3 months, we ascertained 246 cases of death and 2611 cases of hospital admission. Significant hazard ratios (HRs) were observed for all four air pollutants including PM2.5 (hazard ratio [HR] 1.27, 95% confidence interval [95%CI] 1.05-1.54), PM10 (HR 1.31, 95%CI 1.04-1.65), NO2 (HR 1.45, 95%CI 1.02-2.06), and SO2 (HR 1.20, 95%CI 1.10-1.32) in fully adjusted model, corresponding to per interquartile range µg/m3 increase of air pollutant concentrations for mortality, and non-significant HRs for incidence of hospitalization. Non-linear associations with respect to different air pollutants were observed in models for all-cause mortality and recurrent hospitalization. The estimates for mortality were significantly higher in certain groups of patients. Our findings suggest long-term exposure to ambient air pollution was associated with higher risk of all-cause mortality in PD patients, but the association with incidence of hospitalizations was less clear.

Large vessel vasculitis with rare presentation of acute rhabdomyolysis: A case report and review of literature.

BACKGROUND: Musculoskeletal involvement in primary large vessel vasculitis (LVV), including giant cell arteritis and Takayasu's arteritis (TAK), tends to be subacute. With the progression of arterial disease, patients may develop polyarthralgia and myalgias, mainly involving muscle stiffness, limb/jaw claudication, cold/swelling extremities, etc. Acute development of rhabdomyolysis in addition to aortic aneurysm is uncommon in LVV. Herein, we report a rare case of LVV with the first presentation of acute rhabdomyolysis. CASE SUMMARY: A 70-year-old Asian woman suffering from long-term low back pain was hospitalized due to limb claudication, dark urine and an elevated creatine kinase (CK) level. After treatment with fluid resuscitation and antibiotics, the patient remained febrile. Her workup showed persistent elevated levels of inflammatory markers, and imaging studies revealed an aortic aneurysm. A decreasing CK was evidently combined with elevated inflammatory markers and negativity for anti-neutrophilic cytoplasmic antibodies. LVV was suspected and confirmed by magnetic resonance angiography and positron emission tomography with 18F-fluorodeoxyglucose/computed tomography. With a favourable response to immunosuppressive treatment, her symptoms resolved, and clinical remission was achieved one month later. However, after failing to follow the tapering schedule, the patient was readministered 25 mg/d prednisolone due to disease relapse. Follow-up examinations showed decreased inflammatory markers and substantial improvement in artery lesions after 6 mo of treatment. At the twelve-month follow-up, she was clinically stable and maintained on corticosteroid therapy. CONCLUSION: An exceptional presentation of LVV with acute rhabdomyolysis is described in this case, which exhibited a good response to immunosuppressive therapy, suggesting consideration for a differential diagnosis when evaluating febrile patients with myalgia and elevated CK. Timely use of high-dose steroids until a diagnosis is established may yield a favourable outcome.

Short- and long-range interactions in the HIV-1 5' UTR regulate genome dimerization and packaging.

RNA dimerization is the noncovalent association of two human immunodeficiency virus-1 (HIV-1) genomes. It is a conserved step in the HIV-1 life cycle and assumed to be a prerequisite for binding to the viral structural protein Pr55Gag during genome packaging. Here, we developed functional analysis of RNA structure-sequencing (FARS-seq) to comprehensively identify sequences and structures within the HIV-1 5' untranslated region (UTR) that regulate this critical step. Using FARS-seq, we found nucleotides important for dimerization throughout the HIV-1 5' UTR and identified distinct structural conformations in monomeric and dimeric RNA. In the dimeric RNA, key functional domains, such as stem-loop 1 (SL1), polyadenylation signal (polyA) and primer binding site (PBS), folded into independent structural motifs. In the monomeric RNA, SL1 was reconfigured into long- and short-range base pairings with polyA and PBS, respectively. We show that these interactions disrupt genome packaging, and additionally show that the PBS-SL1 interaction unexpectedly couples the PBS with dimerization and Pr55Gag binding. Altogether, our data provide insights into late stages of HIV-1 life cycle and a mechanistic explanation for the link between RNA dimerization and packaging.

The short isoform of the host antiviral protein ZAP acts as an inhibitor of SARS-CoV-2 programmed ribosomal frameshifting.

Programmed ribosomal frameshifting (PRF) is a fundamental gene expression event in many viruses, including SARS-CoV-2. It allows production of essential viral, structural and replicative enzymes that are encoded in an alternative reading frame. Despite the importance of PRF for the viral life cycle, it is still largely unknown how and to what extent cellular factors alter mechanical properties of frameshift elements and thereby impact virulence. This prompted us to comprehensively dissect the interplay between the SARS-CoV-2 frameshift element and the host proteome. We reveal that the short isoform of the zinc-finger antiviral protein (ZAP-S) is a direct regulator of PRF in SARS-CoV-2 infected cells. ZAP-S overexpression strongly impairs frameshifting and inhibits viral replication. Using in vitro ensemble and single-molecule techniques, we further demonstrate that ZAP-S directly interacts with the SARS-CoV-2 RNA and interferes with the folding of the frameshift RNA element. Together, these data identify ZAP-S as a host-encoded inhibitor of SARS-CoV-2 frameshifting and expand our understanding of RNA-based gene regulation.

RNA Structures and Their Role in Selective Genome Packaging.

To generate infectious viral particles, viruses must specifically select their genomic RNA from milieu that contains a complex mixture of cellular or non-genomic viral RNAs. In this review, we focus on the role of viral encoded RNA structures in genome packaging. We first discuss how packaging signals are constructed from local and long-range base pairings within viral genomes, as well as inter-molecular interactions between viral and host RNAs. Then, how genome packaging is regulated by the biophysical properties of RNA. Finally, we examine the impact of RNA packaging signals on viral evolution.

MAFG-AS1 aggravates the progression of pancreatic cancer by sponging miR-3196 to boost NFIX.

BACKGROUND: A host of researches have demonstrated the regulation of long non-coding RNAs (lncRNAs) in the progression of pancreatic cancers (PC). In this study, our main task was to analyze the function of MAF bZIP transcription factor G antisense RNA 1 (MAFG-AS1) in PC. METHODS: RT-qPCR measured gene expression. Functional experiments, including EdU assay, flow cytometry analysis, TUNEL assay and transwell assay, assessed the biological changes of PC cells. RNA pull down assay, luciferase reporter assay and RIP assay verified the interaction between RNAs. RESULTS: MAFG-AS1 was lowly expressed in normal pancreatic samples but up-regulated in PC tissues and cell lines. Besides, MAFG-AS1 silence suppressed cell proliferation and migration whereas promoted cell apoptosis in PC. Mechanism assays verified that miR-3196 could bind with MAFG-AS1. Moreover, miR-3196 was discovered to be lowly expressed in PC cell lines, and its overexpression inhibited PC cell growth and migration. Importantly, nuclear factor I X (NFIX), overexpressed in PC cell lines, was validated to be positively modulated by MAFG-AS1 through absorbing miR-3196. Moreover, overexpression of NFIX could countervail the restraining effects of MAFG-AS1 knockdown on the growth and migration of PC cells. CONCLUSION: MAFG-AS1 had an oncogenic function in the progression of PC via regulating miR-3196/NFIX pathway, and decreasing MAFG-AS1 expression could attenuate PC progression.

IL-1ß Enhances the Antiviral Effect of IFN-α on HCV Replication by Negatively Modulating ERK2 Activation.

Chronic hepatitis C infection is a leading cause of liver cirrhosis, which is linked to chronic hepatic inflammation. While there are multiple studies detailing the proinflammatory role of interleukin-1ß (IL-1ß) in HCV-induced inflammasome signaling, the antiviral capacity of this cytokine has not been adequately investigated in the context of HCV infection or other members of Flaviridae. Our data indicated that IL-1ß alone does not inhibit HCV replication, yet when in combination with IFN-α, it can boost the anti-HCV activity of IFN-α, which is mediated by augmented STAT1 tyrosine 701 phosphorylation. Through signaling inhibitor screening, we found that ERK2 kinase is directly linked to the enhanced activation of the STAT1 complex. Our study found that IL-1ß negatively affects ERK2 phosphorylation, which suggests that IL-1ß-mediated STAT1 tyrosine 701 phosphorylation employed kinase machinery of ERK2 other than JNK or P38 kinase. Our results identify IL-1ß as a proinflammatory cytokine possessing wide spectrum synergistic antiviral capability via enhancing IFN-α-induced interferon-stimulated genes (ISGs) expression. A more nuanced understanding of the antiviral mechanisms of this important cytokine could facilitate the development of new therapeutic options.

Neuralized E3 Ubiquitin Protein Ligase 3 Is an Inducible Antiviral Effector That Inhibits Hepatitis C Virus Assembly by Targeting Viral E1 Glycoprotein.

Hepatitis C virus (HCV) infection is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV can be sensed by host innate immunity to induce expression of interferons (IFNs) and a number of antiviral effectors. In this study, we found HCV infection induced the expression of neuralized E3 ubiquitin protein ligase 3 (NEURL3), a putative E3 ligase, in a manner that requires the involvement of innate immune sensing but is independent of the IFN action. Furthermore, we showed that NEURL3 inhibited HCV infection while it had little effect on other RNA viruses, including Zika virus (ZIKV), dengue virus (DENV), and vesicular stomatitis virus (VSV). Mechanistic studies demonstrated that NEURL3 inhibited HCV assembly by directly binding HCV envelope glycoprotein E1 to interfere with the E1/E2 heterodimerization, an important prerequisite for virion morphogenesis. Finally, we showed that knockout of NEURL3 significantly enhanced HCV infection. In summary, we identified NEURL3 as a novel inducible antiviral host factor that suppresses HCV assembly. Our results not only shed new insight into how host innate immunity acts against HCV but also revealed a new important biological function for NEURL3.IMPORTANCE The exact biological function of NEURL3, a putative E3 ligase, remains largely unknown. In this study, we found that NEURL3 could be upregulated upon HCV infection in a manner dependent on pattern recognition receptor-mediated innate immune response. NEURL3 inhibits HCV assembly by directly binding viral E1 envelope glycoprotein to disrupt its interaction with E2, an action that requires its Neuralized homology repeat (NHR) domain but not the RING domain. Furthermore, we found that NEURL3 has a pangenotypic anti-HCV activity and interacts with E1 of genotypes 2a, 1b, 3a, and 6a but does not inhibit other closely related RNA viruses, such as ZIKV, DENV, and VSV. To our knowledge, our study is the first report to demonstrate that NEURL3 functions as an antiviral host factor. Our results not only shed new insight into how host innate immunity acts against HCV, but also revealed a new important biological function for NEURL3.

[Photometric micro-titration model of DPPH radicals scavenging activity and its application].

In the present paper, the stoichiometric ratio (R) for the interreaction of DPPH radicals with the antoxidant was employed as a evaluation index for DPPH radicals scavenging activity of antioxidants. This evaluation index was related only with the stoichiometric relationship between DPPH radicals and the antioxidant, not the relationship with the initial DPPH amount and the volume of sample, which could offer a solution for the problem of poor comparability of EC50 under different conditions. A novel photometric micro-titration method was proposed for the determination of the stoichiometric ratio (R) for the interreaction of DPPH radicals with the antoxidant. The titration equation was established based on the absorbance difference (deltaA) of DPPH radicals in the titration process and the added amount of antoxidant. The stoichiometric ratio (R) for the reaction of DPPH radicals with the addition amount of antoxidant was determined by the titration equation obtained, while, the DPPH median elimination concentration (EC50) of antoxidant can be calculated by the stoichiometric ratio (R). The above photometric micro-titration model was verified using rutin as DPPH radicals scavenger. As experiment results, the stoichiometric ratio (R) of DPPH radicals to rutin was determined to be in the range of 1.817-1.846. The calculated value of EC50 was 1.196 x 10(-3), 2.392 x 10(-3), 4.819 x 10(-3) and 7.292 x 10(-3) mg x mL(-1) for 1.12 x 10(-7), 2.24 x 10(-7), 4.48 x 10(-7) and 6.72 x 10(-7) mol of the additon amount of DPPH radicals, respectively. The proposed method has better precision and reliability with smaller amount of sample than conventional method. While, the obtained stoichiometric ratio value (R) of rutin was employed to calculate the rutin median elimination concentration for DPPH EC50) according to the conditions as reported in the literatures, and the calculated results were consistent with that reported in the literatures.

Investigation of analytical performance for rapidly synergistic cloud point extraction of trace amounts of copper combined with spectrophotometric determination.

In this work, an improved preconcentration method named as rapidly synergistic cloud point extraction (RS-CPE) was established for copper preconcentration and determination. Non-ionic surfactant Triton X-100 (TX-100) was used as extractant. Octanol worked as cloud point revulsant and synergic reagent, which successfully decreased the cloud point temperature (CPT) of TX-100 to realize the room temperature (about 20°C) CPE without heating. The established RS-CPE pretreatment was simple, rapid and effective. Compared with traditional CPE (about 40 min for heating, incubation and cooling), the extraction time of the proposed method was very short (1 min). The improved extraction technique RS-CPE was combined with traditional spectrophotometer to improve the analytical performance and expand the application of spectrophotometric determination. The influence factors relevant to RS-CPE, such as concentrations of TX-100 and octanol, concentration of chelating agent, pH, conditions of phase separation, salt effect, environmental temperature and instrumental conditions, were studied in detail. Under the optimal conditions, the limit of detection (LOD) for copper was 0.4 µg L(-1), with sensitivity enhancement factor (EF) of 18. The proposed method was applied to the determination of trace copper in real samples and certified samples with satisfactory analytical results.

[Preparation of a 96-microwell plate DNA diagnostic chip for detection of foodborne bacteria and its application in an incident of food poisoning].

OBJECTIVE: To develop a 96-microwell plate DNA diagnostic chip for simultaneous detection of 9 major foodborne bacteria. METHODS: Type-specific PCR primers labeled with biotin and oligonucleotide probes were designed according to the conservative genes of 9 major foodborne bacteria Staphylococcus aureus, Salmonella spp., Escherichia coli O157:H7 (Stx1 and Stx2), Shigella spp., Listeria monocytogenes, Bacillus cereus, Yersinia enterocolitica, Vibrio cholerae and Vibrio parahaemolyticus. A one-tube multiplex PCR system for simultaneous amplification of these bacteria was established, and the DNA probes were spotted and immobilized in the wells of the plate in 5x5 array format. Stable hybridization system between PCR products and oligonucleotide probes in the microwell was established after condition optimization. Alkaline phosphatase-conjugated streptavidin and NBT/BCIP were used to detect the hybridized PCR products. RESULTS: Twenty standard bacteria strains were used to validate the 96 microwell plate DNA diagnostic chip and highly specific and stable experiment results were obtained. Using this chip assay, the causal pathogen Staphylococcus aureus was identified within 12 h after the sampling from an incident of food poisoning, and the result was consistent with that obtained using conventional bacterial culture and biochemical identification. CONCLUSION: The novel 96 microwell plate DNA diagnostic chip allows rapid, accurate, automated and high-throughput bacterial detection and is especially valuable for quick response to such public health emergencies as food poisoning.

[One-step multiplex RT-PCR for rapid screening of type A, B and novel A (H1N1) influenza viruses].

OBJECTIVE: To developed a multiplex RT-PCR assay for simultaneous screening of type A, B and novel A (H1N1) influenza viruses. METHODS: Two pairs of universal primers in were designed for amplifying the M gene and NS gene of type A and B influenza viruses, respectively. A pair of specific primers of HA gene was designed to detect novel A (H1N1) influenza virus. A one-step method was used to establish the multiplex RT-PCR system. A blinded experiment was carried out to validate the accuracy of this assay in comparison with the results of real-time fluorescence RT-PCR. The clinical practicability and efficacy of this assay was also evaluated. RESULTS: The RT-PCR products were analyzed using agarose gel electrophoresis, which yielded distinct bands of the target fragments without non-specific reactions, suggesting the high efficiency and specificity of the multiplex RT-PCR. Blinded study of 50 samples demonstrated a concordance rate of 100%. CONCLUSION: This multiplex RT-PCR assay allows one-step simultaneous detection of type A, B and novel A (H1N1) influenza viruses rapidly and accurately, and provides a valuable low-cost screening technique for influenza epidemic monitoring and early diagnosis.