The ongoing worldwide SARS-CoV-2 epidemic clearly has a tremendous influence on public health. Molecular detection based on oral swabs was used for confirmation of SARS-CoV-2 infection. However, high ...false negative rates were reported. We describe here the development of a point-of-care (POC) serological assay for the detection of IgG antibody against SARS-CoV-2. The principle of a lateral flow immunoassay strip (LFIAs) consists of fixing SARS-CoV-2 nucleocapsid protein to the surface of the strip and coupling anti-human IgG with colloidal gold nanoparticles (Au NPs). A series of parameters of this method were optimized, including the concentration of coating antigen, BSA blocking concentration and pH value for conjugation. The entire detection process took 15-20 min with a volume of 80 μL of the analyte solution containing 10 μL of serum and 70 μL sample diluent. The performance of the established assay was evaluated using serum samples of the clinically diagnosed cases of Coronavirus Disease 2019 (COVID-19). Our results indicated that the LFIAs for SARS-CoV-2 had satisfactory stability and reproducibility. As a result, our fast and easy LFIAs could provide a preliminary test result for physicians to make the correct diagnosis of SARS-CoV-2 infections along with alternative testing methods and clinical findings, as well as seroprevalence determination, especially in low-resource countries.
Last year, the novel coronavirus
disease (COVID-19) emerged in
Wuhan, and it has rapidly spread to many other countries and regions.
COVID-19 exhibits a strong human-to-human transmission infectivity
...and could cause acute respiratory diseases. Asymptomatic carriers
are able to infect other healthy persons, and this poses a challenge
for public health; the World Health Organization (WHO) has already
announced COVID-19 as a global pandemic. Nucleic acid testing, considered
as the current primary method for diagnosing COVID-19, might lead
to false negatives and is difficult to be applied for every suspected
patient because of the existence of asymptomatic carriers. Meanwhile,
detecting specific antibodies in blood, such as the IgM antibody,
against the SARS-CoV-2 virus is another choice for COVID-19 diagnosis,
as it is widely accepted that IgM is an important indicator in the
acute infection period. In this study, a colloidal gold nanoparticle-based
lateral-flow (AuNP-LF) assay was developed to achieve rapid diagnosis
and on-site detection of the IgM antibody against the SARS-CoV-2 virus
through the indirect immunochromatography method. For preparing AuNP-LF
strips, the SARS-CoV-2 nucleoprotein (SARS-CoV-2 NP) was coated on
an analytical membrane for sample capture, and antihuman IgM was conjugated
with AuNPs to form the detecting reporter. Optimization of AuNP-LF
assay was carried out by altering the pH value and the amount of antihuman
IgM. The performance of AuNP-LF assay was evaluated by testing serum
samples of COVID-19 patients and normal humans. The results were compared
with the real-time polymerase chain reaction. The sensitivity and
specificity of AuNP-LF assay were determined to be 100 and 93.3%,
respectively, and an almost perfect agreement was exhibited by Kappa
statistics (κ coefficient = 0.872). AuNP-LF assay showed outstanding
selectivity in the detection of IgM against the SARS-CoV-2 virus with
no interference from other viruses such as severe fever with thrombocytopenia
syndrome virus (SFTSV) and dengue virus (DFV). AuNP-LF assay was able
to achieve results within 15 min and needed only 10–20 μL
serum for each test. As a whole, in the light of its advantages such
as excellent specificity and stability, easy operation, low cost,
and being less time-consuming, AuNP-LF assay is a feasible method
for the diagnosis of COVID-19 in primary hospitals and laboratories,
especially in emergency situations in which numerous samples need
to be tested on time.
Although the fates of microplastics (0.1-5 mm in size) and nanoplastics (<100 nm) in marine environments are being increasingly well studied
, little is known about the behaviour of nanoplastics in ...terrestrial environments
, especially agricultural soils
. Previous studies have evaluated the consequences of nanoplastic accumulation in aquatic plants, but there is no direct evidence for the internalization of nanoplastics in terrestrial plants. Here, we show that both positively and negatively charged nanoplastics can accumulate in Arabidopsis thaliana. The aggregation promoted by the growth medium and root exudates limited the uptake of amino-modified polystyrene nanoplastics with positive surface charges. Thus, positively charged nanoplastics accumulated at relatively low levels in the root tips, but these nanoplastics induced a higher accumulation of reactive oxygen species and inhibited plant growth and seedling development more strongly than negatively charged sulfonic-acid-modified nanoplastics. By contrast, the negatively charged nanoplastics were observed frequently in the apoplast and xylem. Our findings provide direct evidence that nanoplastics can accumulate in plants, depending on their surface charge. Plant accumulation of nanoplastics can have both direct ecological effects and implications for agricultural sustainability and food safety.
Low back pain (LBP), as a leading cause of disability, is a common musculoskeletal disorder that results in major social and economic burdens. Recent research has identified inflammation and related ...signaling pathways as important factors in the onset and progression of disc degeneration, a significant contributor to LBP. Inflammatory mediators also play an indispensable role in discogenic LBP. The suppression of LBP is a primary goal of clinical practice but has not received enough attention in disc research studies. Here, an overview of the advances in inflammation-related pain in disc degeneration is provided, with a discussion on the role of inflammation in IVD degeneration and pain induction. Puncture models, mechanical models, and spontaneous models as the main animal models to study painful disc degeneration are discussed, and the underlying signaling pathways are summarized. Furthermore, potential drug candidates, either under laboratory investigation or undergoing clinical trials, to suppress discogenic LBP by eliminating inflammation are explored. We hope to attract more research interest to address inflammation and pain in IDD and contribute to promoting more translational research.
Bone metabolic disorders include osteolysis, osteoporosis, osteoarthritis and rheumatoid arthritis. Osteoblasts and osteoclasts are two major types of cells in bone constituting homeostasis. The ...imbalance between bone formation by osteoblasts and bone resorption by osteoclasts has been shown to have a direct contribution to the onset of these diseases. Recent evidence indicates that autophagy and mitophagy, the selective autophagy of mitochondria, may play a vital role in regulating the proliferation, differentiation and function of osteoblasts and osteoclasts. Several signaling pathways, including PINK1/Parkin, SIRT1, MAPK8/FOXO3, Beclin-1/BECN1, p62/SQSTM1, and mTOR pathways, have been implied in the regulation of autophagy and mitophagy in these cells. Here we review the current progress about the regulation of autophagy and mitophagy in osteoblasts and osteoclasts in these bone metabolic disorders, as well as the molecular signaling activated or deactivated during this process. Together, we hope to draw attention to the role of autophagy and mitophagy in bone metabolic disorders, and their potential as a new target for the treatment of bone metabolic diseases and the requirements of further mechanism studies.
Information overload often makes it difficult for consumers to identify helpful online product reviews through the traditional “helpful votes” function; therefore, it has become particularly ...important to efficiently identify helpful reviews. By differentiating search products from experience products, this research examines the impact of different measurements of review informativeness on review helpfulness, and proposes different classification thresholds to individually identify the helpfulness of online reviews for search products and for experience products, respectively. Further, our study applies machine learning algorithms to predict the performance of the classification based on our proposed review informativeness measurements and classification thresholds. All experiments were conducted using a dataset from JD.com, one of the largest online electronic marketplaces in China. Our results offer guidelines to design different helpfulness classification standards for search products and for experience products.
•Differences between search products and experience products moderate consumers' perception about review helpfulness.•We analyze how review informativeness affects review helpfulness by product type.•We confirm different classification thresholds for search and experience products.•Improved classification performance through our proposed variables and thresholds•Both the number of attributes and the average length of attributes measure review informativeness.
Using observed data sets from 1979 to 2006, the relationship between El Niño Modoki and spring rainfall over south China (SC) is investigated. Of particular interest is the difference in the ...influence on spring rainfall of typical El Niño events and the recently recognized El Niño Modoki events, which are characterized by distinct warm sea surface temperature anomalies (SSTA) in the central Pacific and weaker cold anomalies in the western and eastern parts of the basin. Associated with the SSTA, anomalous ascent occurs over the central Pacific and downward flow is observed over the eastern and western Pacific. The anomalous flow is associated with anomalous convergence in the upper troposphere over the western Pacific. SC is influenced by an anomalous anticyclonic circulation with prevailing northeasterly anomalies. The convective activity in SC becomes weaker, resulting in reduced rainfall. However, the situation is different in the case of El Niño, in terms of the influence on rainfall over SC. While El Niño Modoki events are accompanied by a significant reduction in rainfall over SC, there is enhanced rainfall associated with El Niño events. Moreover, there exists a strong asymmetry in the relationship between SC spring rainfall, typical El Niño–Southern Oscillation (ENSO) and ENSO Modoki events. It appears that these relationships are only statistically significant for positive events. The asymmetric influence of positive and negative in two ENSO phenomena may explain the difference in their respective relationships with spring rainfall over SC.
Key Points
We find El Nino Modoki has a strong influence on south China spring rainfall
The influence of ENSO on SC spring rainfall is positive
There exists an asymmetry in the relation of ENSO Modoki and SC rainfall
The concept of mesenchymal stem cells (MSCs) is becoming increasingly obscure due to the recent findings of heterogeneous populations with different levels of stemness within MSCs isolated by ...traditional plastic adherence. MSCs were originally identified in bone marrow and later detected in many other tissues. Currently, no cloning based on single surface marker is capable of isolating cells that satisfy the minimal criteria of MSCs from various tissue environments. Markers that associate with the stemness of MSCs await to be elucidated. A number of candidate MSC surface markers or markers possibly related to their stemness have been brought forward so far, including Stro-1, SSEA-4, CD271, and CD146, yet there is a large difference in their expression in various sources of MSCs. The exact identity of MSCs in vivo is not yet clear, although reports have suggested they may have a fibroblastic or pericytic origin. In this review, we revisit the reported expression of surface molecules in MSCs from various sources, aiming to assess their potential as MSC markers and define the critical panel for future investigation. We also discuss the relationship of MSCs to fibroblasts and pericytes in an attempt to shed light on their identity in vivo.
Huntington's disease (HD) is a neurodegenerative disorder caused by a mutation in the huntingtin (HTT) gene that results in the production of neurotoxic mutant HTT (mHTT) protein. Suppressing HTT ...production with antisense oligonucleotides (ASOs) is a promising treatment strategy for HD; however, the difficulty of delivering ASOs to deep brain structures is a major barrier for its clinical application. The glymphatic system of astrocytes involving aquaporin 4 (AQP-4) controls the entry of macromolecules from the cerebrospinal fluid into the brain. Mesenchymal stem cells (MSCs) target astrocytes to inhibit neuroinflammation. Here we examined the glymphatic distribution of ASO in the brain and the therapeutic potential of combining intravenously injection of mesenchymal stem cells (IV-MSC) and ASOs for the treatment of HD. Our results show that Cy3-labeled ASOs entered the brain parenchyma via the perivascular space following cisternal injection, but the brain distribution was significantly lower in AQP-4
as compared with wild-type mice. Downregulation of the AQP-4 M23 isoform was accompanied by decreased brain levels of ASOs in BACHD mice as well as an increase in astrogliosis and phosphorylation of nuclear factor κB (NF-κB) p65. IV-MSC treatment restored AQP-4 M23 expression, attenuated astrogliosis, and decreased NF-κB p65 phosphorylation; it also increased the brain distribution of ASOs and enhanced the suppression of mHTT in BACHD mice. These results suggest that modulating glymphatic activity using IV-MSC is a novel strategy for improving the potency of ASO in the treatment of HD.
Intervertebral disc (IVD) herniation and degeneration contributes significantly to low back pain (LBP), of which the molecular pathogenesis is not fully understood. Disc herniation may cause LBP and ...radicular pain, but not all LBP patients have disc herniation. Degenerated discs could be the source of pain, but not all degenerated discs are symptomatic. We previously found that disc degeneration and herniation accompanied by inflammation. We further found that anti‐inflammatory molecules blocked immune responses, alleviated IVD degeneration and pain. Based on our recent findings and the work of others, we hypothesize that immune system may play a prominent role in the production of disc herniation or disc degeneration associated pain. While the nucleus pulposus (NP) is an immune‐privileged organ, the damage of the physical barrier between NP and systemic circulation, or the innervation and vascularization of the degenerated NP, on one hand exposes NP as a foreign antigen to immune system, and on the other hand presents compression on the nerve root or dorsal root ganglion (DRG), which both elicit immune responses induced by immune cells and their mediators. The inflammation can remain for a long time at remote distance, with various types of cytokines and immune cells involved in this pain‐inducing process. In this review, we aim to revisit the autoimmunity of the NP, immune cell infiltration after break of physical barrier, the inflammatory activities in the DRG and the generation of pain. We also summarize the involvement of immune system, including immune cells and cytokines, in degenerated or herniated IVDs and affected DRG.
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