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1.
Bioeng Transl Med ; 5(3): e10177, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-1898553

ABSTRACT

The Coronavirus-2019 (COVID-19) pandemic has put tremendous strain on healthcare systems worldwide. It is challenging for clinicians to differentiate COVID-19 from other acute respiratory tract infections via clinical symptoms because those who are infected display a wide range of symptoms. An effective, point-of-care (POC) diagnostic tool could mitigate healthcare system strain, protect healthcare professionals, and support quarantine efforts. We believe that a POC tool can be developed that would be rapid, easy to use, and inexpensive. It could be used in the home, in resource-limited areas, and even in clinical settings. In this article, we summarize the current state of COVID-19 diagnostic methods and make a case for an all-in-one, highly sensitive POC assay that integrates antibody detection, protein detection, and serum cytokine detection to diagnose COVID-19 infection. We believe this article will provide insights into the current state of diagnostics for COVID-19, and promote additional research and tool development that could be exceptionally impactful.

2.
J Anal Toxicol ; 46(4): 449-456, 2022 Apr 21.
Article in English | MEDLINE | ID: covidwho-1806445

ABSTRACT

Over the last 25 years, marijuana laws have been changing throughout the USA. California started legalizing medicinal marijuana in 1996 and has since continued to relax laws. Compared to Washington and Colorado, there are little data on how the changing laws have affected the cannabinoid detection rate in California. This paper looks at the prevalence of five cannabinoids (Δ9-tetrahydrocannabinol (THC), 11-hydroxy-tetrahydrocannabinol (hydroxy-THC), 11-nor-9-carboxy-tetrahydrocannabinol (carboxy-THC), cannabinol and cannabidiol) in Orange County, CA, from 2016 to 2019. From 2016 to 2017, after legalizing recreational marijuana, there was an increase in the presence of THC, carboxy-THC and hydroxy-THC in postmortem and major crime cases, consisting mostly of sexual assaults. However, driving under the influence of drugs (DUID) saw a slight decrease. In 2018, when shops could be licensed to sell marijuana to anyone over 21 years old, there was an increase seen in all five cannabinoids for DUID and postmortem cases. The age group from 21 to 30 years showed the most prevalent cannabinoid use in all case types for all years except in major crime cases in 2019, where <21 year-old age group was the most prevalent. Surprisingly, the >50-year-old group in death investigation cases was a close second in prevalence in all years, which differs from DUID and major crime cases.


Subject(s)
Cannabinoids , Cannabis , Hallucinogens , Cannabinol , Dronabinol , Forensic Toxicology , Prevalence , Substance Abuse Detection
3.
Klin Lab Diagn ; 65(11): 683-687, 2020 Dec 04.
Article in English | MEDLINE | ID: covidwho-1780382

ABSTRACT

A new original Russian test kit for the detection of IgG-antibodies to the causative agent of COVID-19 - coronavirus SARS-CoV-2 by the method of enzyme-linked immunosorbent assay (ELISA) on a solid-phase «ELISA-SARS-CoV-2-AT-G¼ has been developed. In comparative tests with similar test systems «Vitrotest® SARS-CoV-2 IgG¼ (Vitrotest, Ukraine) and «Anti-SARS-Cov-2 ELISA (IgG)¼ (EUROIMMUN AG, Germany) high diagnostic efficiency of the new test system was shown.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Serological Testing , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay , Immunoglobulin G/analysis , Clinical Laboratory Techniques , Humans , Plasma , Reagent Kits, Diagnostic
4.
Klin Lab Diagn ; 66(4): 210-212, 2021 Apr 17.
Article in English | MEDLINE | ID: covidwho-1780502

ABSTRACT

To study the diagnostic characteristics of test systems for detecting antibodies to SARS-Cov-2. We studied the diagnostic characteristics of two test systems for detecting antibodies to SARS-Cov-2, registered in the Russian Federation. The first test system is a kit for detecting total antibodies to SARS-Cov-2 using immunochemiluminescence analysis on the «Cobas e 411¼ analyzer («Roche Diagnostics¼, Germany). The second test system is a kit for detecting IgM and IgG to SARS-Cov-2 («Core Technology Co., Ltd¼, China) by immunochromatographic analysis. The biological material for the study was blood serum. We assessed: diagnostic sensitivity, diagnostic specificity, and predictive value of positive and negative results. In the test system for detecting total antibodies to SARS-CoV-2, using an IHLA, the diagnostic sensitivity and specificity were 100%; the predictive value of positive and negative results was 100%. In the test system for the detection of IgM and IgG to Sars-CoV-2, using IHA, diagnostic sensitivity for IgM and IgG were 100%; diagnostic specificity for IgM - 60%, for IgG - 72%; predictive value of a positive result for IgM - 60%, IgG - 68,18%; predictive value of negative results for IgM and IgG - 100%. The best diagnostic characteristics were found in the test system for the detection of total antibodies to SARS-Cov-2, which must be taken into account when deciding whether to purchase test systems for the detection of antibodies to SARS-Cov-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Humans , Immunoglobulin G , Immunoglobulin M , Russia , Sensitivity and Specificity , Serologic Tests
5.
J Nucl Med ; 62(11): 1631-1637, 2021 11.
Article in English | MEDLINE | ID: covidwho-1496930

ABSTRACT

In this study, we developed angiotensin-converting enzyme 2 (ACE2)-specific, peptide-derived 68Ga-labeled radiotracers, motivated by the hypotheses that ACE2 is an important determinant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) susceptibility and that modulation of ACE2 in coronavirus disease 2019 (COVID-19) drives severe organ injury. Methods: A series of NOTA-conjugated peptides derived from the known ACE2 inhibitor DX600 were synthesized, with variable linker identity. Since DX600 bears 2 cystine residues, both linear and cyclic peptides were studied. An ACE2 inhibition assay was used to identify lead compounds, which were labeled with 68Ga to generate peptide radiotracers (68Ga-NOTA-PEP). The aminocaproate-derived radiotracer 68Ga-NOTA-PEP4 was subsequently studied in a humanized ACE2 (hACE2) transgenic model. Results: Cyclic DX-600-derived peptides had markedly lower half-maximal inhibitory concentrations than their linear counterparts. The 3 cyclic peptides with triglycine, aminocaproate, and polyethylene glycol linkers had calculated half-maximal inhibitory concentrations similar to or lower than the parent DX600 molecule. Peptides were readily labeled with 68Ga, and the biodistribution of 68Ga-NOTA-PEP4 was determined in an hACE2 transgenic murine cohort. Pharmacologic concentrations of coadministered NOTA-PEP (blocking) showed a significant reduction of 68Ga-NOTA-PEP4 signals in the heart, liver, lungs, and small intestine. Ex vivo hACE2 activity in these organs was confirmed as a correlate to in vivo results. Conclusion: NOTA-conjugated cyclic peptides derived from the known ACE2 inhibitor DX600 retain their activity when N-conjugated for 68Ga chelation. In vivo studies in a transgenic hACE2 murine model using the lead tracer, 68Ga-NOTA-PEP4, showed specific binding in the heart, liver, lungs and intestine-organs known to be affected in SARS-CoV-2 infection. These results suggest that 68Ga-NOTA-PEP4 could be used to detect organ-specific suppression of ACE2 in SARS-CoV-2-infected murine models and COVID-19 patients.


Subject(s)
Angiotensin-Converting Enzyme 2 , Gallium Radioisotopes/chemistry , Peptides, Cyclic , Animals , Male , Mice , Positron-Emission Tomography , Tissue Distribution
6.
Viruses ; 12(12)2020 11 30.
Article in English | MEDLINE | ID: covidwho-1389520

ABSTRACT

Aptamers are short fragments of nucleic acids, DNA or RNA that have the ability to bind selected proteins with high specificity and affinity. These properties allow them to be used as an element of biosensors for the detection of specific proteins, including viral ones, which makes it possible to design valuable diagnostic tools. The influenza virus causes a huge number of human and animal deaths worldwide every year, and contributes to remarkable economic losses. In addition, in 2020, a new threat appeared-the SARS-Cov-2 pandemic. Both disease entities, especially in the initial stage of infection, are almost identical in terms of signs and symptoms. Therefore, a diagnostic solution is needed that will allow distinguishing between both pathogens, with high sensitivity and specificity; it should be cheap, quick and possible to use in the field, for example, in a doctor's office. All the mentioned properties are met by aptasensors in which the detection elements are specific aptamers. We present here the latest developments in the construction of various types of aptasensors for the detection of influenza virus. Aptasensor operation is based on the measurement of changes in electric impedance, fluorescence or electric signal (impedimetric, fluorescence and electrochemical aptasensors, respectively); it allows both qualitative and quantitative determinations. The particularly high advancement for detecting of influenza virus concerns impedimetric aptasensors.


Subject(s)
Aptamers, Nucleotide/therapeutic use , Biosensing Techniques , Influenza, Human/diagnosis , Orthomyxoviridae/isolation & purification , Aptamers, Nucleotide/genetics , COVID-19/diagnosis , Electric Impedance , Electrochemical Techniques , Fluorescence , Humans , SARS-CoV-2/isolation & purification
8.
Biotechnol Prog ; 37(2): e3112, 2021 03.
Article in English | MEDLINE | ID: covidwho-1384129

ABSTRACT

Angiotensin II (AngII), the effector peptide of the renin angiotensin system and has an important role in regulating cardiovascular hemodynamics and structure. AngII is an important biomarker for certain diseases that are associated with cardiovascular disorders, i.e., influenza, SARS-CoV-2, tumors, hypertension, etc. However, AngII presents in blood in very low concentrations and they are not stable due to their reactivity, therefore spontaneous detection of AngII is a big challenge. In this study, AngII-imprinted spongy columns (AngII-misc) synthesized for AngII detection from human serum, and characterized by surface area measurements (BET), swelling tests, scanning electron microscopy (SEM), FTIR studies. AngII binding studies were achieved from aqueous environment and maximum binding capacity was found as 0.667 mg/g. It was calculated that the AngII-miscs recognized AngII 8.27 and 14.25 times more selectively than competitor Angiotensin I and Vasopressin molecules. Newly produced AngII-misc binds 60.5 pg/g AngII from crude human serum selectively. It has a great potential for spontaneous detection of AngII from human serum for direct and critical measurements in serious diseases, that is, heart attacks, SARS-CoV-2, etc.


Subject(s)
Angiotensin II/blood , Molecularly Imprinted Polymers , Angiotensin II/isolation & purification , Biomarkers/blood , Humans , Protein Binding
9.
Front Genet ; 12: 618170, 2021.
Article in English | MEDLINE | ID: covidwho-1389158

ABSTRACT

The exponential growth of genome sequences available has spurred research on pattern detection with the aim of extracting evolutionary signal. Traditional approaches, such as multiple sequence alignment, rely on positional homology in order to reconstruct the phylogenetic history of taxa. Yet, mining information from the plethora of biological data and delineating species on a genetic basis, still proves to be an extremely difficult problem to consider. Multiple algorithms and techniques have been developed in order to approach the problem multidimensionally. Here, we propose a computational framework for identifying potentially meaningful features based on k-mers retrieved from unaligned sequence data. Specifically, we have developed a process which makes use of unsupervised learning techniques in order to identify characteristic k-mers of the input dataset across a range of different k-values and within a reasonable time frame. We use these k-mers as features for clustering the input sequences and identifying differences between the distributions of k-mers across the dataset. The developed algorithm is part of an innovative and much promising approach both to the problem of grouping sequence data based on their inherent characteristic features, as well as for the study of changes in the distributions of k-mers, as the k-value is fluctuating within a range of values. Our framework is fully developed in Python language as an open source software licensed under the MIT License, and is freely available at https://github.com/BiodataAnalysisGroup/kmerAnalyzer.

10.
Genome Biol ; 22(1): 169, 2021 06 03.
Article in English | MEDLINE | ID: covidwho-1388811

ABSTRACT

BACKGROUND: Rapid spread of SARS-CoV-2 has led to a global pandemic, resulting in the need for rapid assays to allow diagnosis and prevention of transmission. Reverse transcription-polymerase chain reaction (RT-PCR) provides a gold standard assay for SARS-CoV-2 RNA, but instrument costs are high and supply chains are potentially fragile, motivating interest in additional assay methods. Reverse transcription and loop-mediated isothermal amplification (RT-LAMP) provides an alternative that uses orthogonal and often less expensive reagents without the need for thermocyclers. The presence of SARS-CoV-2 RNA is typically detected using dyes to report bulk amplification of DNA; however, a common artifact is nonspecific DNA amplification, which complicates detection. RESULTS: Here we describe the design and testing of molecular beacons, which allow sequence-specific detection of SARS-CoV-2 genomes with improved discrimination in simple reaction mixtures. To optimize beacons for RT-LAMP, multiple locked nucleic acid monomers were incorporated to elevate melting temperatures. We also show how beacons with different fluorescent labels can allow convenient multiplex detection of several amplicons in "single pot" reactions, including incorporation of a human RNA LAMP-BEAC assay to confirm sample integrity. Comparison of LAMP-BEAC and RT-qPCR on clinical saliva samples showed good concordance between assays. To facilitate implementation, we developed custom polymerases for LAMP-BEAC and inexpensive purification procedures, which also facilitates increasing sensitivity by increasing reaction volumes. CONCLUSIONS: LAMP-BEAC thus provides an affordable and simple SARS-CoV-2 RNA assay suitable for population screening; implementation of the assay has allowed robust screening of thousands of saliva samples per week.


Subject(s)
COVID-19/diagnosis , RNA, Viral/genetics , SARS-CoV-2/isolation & purification , COVID-19 Testing , Humans , Molecular Diagnostic Techniques , Nucleic Acid Amplification Techniques , Nucleic Acid Probes/genetics , SARS-CoV-2/genetics , Saliva/virology , Sensitivity and Specificity
11.
mBio ; 12(2)2021 04 13.
Article in English | MEDLINE | ID: covidwho-1388457

ABSTRACT

Mammalian cells detect microbial molecules known as pathogen-associated molecular patterns (PAMPs) as indicators of potential infection. Upon PAMP detection, diverse defensive responses are induced by the host, including those that promote inflammation and cell-intrinsic antimicrobial activities. Host-encoded molecules released from dying or damaged cells, known as damage-associated molecular patterns (DAMPs), also induce defensive responses. Both DAMPs and PAMPs are recognized for their inflammatory potential, but only the latter are well established to stimulate cell-intrinsic host defense. Here, we report a class of DAMPs that engender an antiviral state in human epithelial cells. These DAMPs include oxPAPC (oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine), PGPC (1-palmitoyl-2-glutaryl phosphatidylcholine), and POVPC [1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphatidylcholine], oxidized lipids that are naturally released from dead or dying cells. Exposing cells to these DAMPs prior to vesicular stomatitis virus (VSV) infection limits viral replication. Mechanistically, these DAMPs prevent viral entry, thereby limiting the percentage of cells that are productively infected and consequently restricting viral load. We found that the antiviral actions of oxidized lipids are distinct from those mediated by the PAMP Poly I:C, in that the former induces a more rapid antiviral response without the induction of the interferon response. These data support a model whereby interferon-independent defensive activities can be induced by DAMPs, which may limit viral replication before PAMP-mediated interferon responses are induced. This antiviral activity may impact viruses that disrupt interferon responses in the oxygenated environment of the lung, such as influenza virus and SARS-CoV-2.IMPORTANCE In this work, we explored how a class of oxidized lipids, spontaneously created during tissue damage and unprogrammed cell lysis, block the earliest events in RNA virus infection in the human epithelium. This gives us novel insight into the ways that we view infection models, unveiling a built-in mechanism to slow viral growth that neither engages the interferon response nor is subject to known viral antagonism. These oxidized phospholipids act prior to infection, allowing time for other, better-known innate immune mechanisms to take effect. This discovery broadens our understanding of host defenses, introducing a soluble factor that alters the cellular environment to protect from RNA virus infection.


Subject(s)
Alarmins/pharmacology , Antiviral Agents/pharmacology , RNA Viruses/drug effects , Virus Internalization/drug effects , Virus Replication/drug effects , A549 Cells , Cell Death/drug effects , Humans , Immunity, Innate , Interferons/genetics , Interferons/metabolism , Kinetics , Pathogen-Associated Molecular Pattern Molecules/pharmacology , Phosphatidylcholines/pharmacology , RNA Viruses/physiology , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Vesiculovirus/drug effects , Vesiculovirus/physiology , Viral Load
13.
J Med Virol ; 93(9): 5481-5486, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1363685

ABSTRACT

As severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections continue, there is a substantial need for cost-effective and large-scale testing that utilizes specimens that can be readily collected from both symptomatic and asymptomatic individuals in various community settings. Although multiple diagnostic methods utilize nasopharyngeal specimens, saliva specimens represent an attractive alternative as they can rapidly and safely be collected from different populations. While saliva has been described as an acceptable clinical matrix for the detection of SARS-CoV-2, evaluations of analytic performance across platforms for this specimen type are limited. Here, we used a novel sensitive RT-PCR/MALDI-TOF mass spectrometry-based assay (Agena MassARRAY®) to detect SARS-CoV-2 in saliva specimens. The platform demonstrated high diagnostic sensitivity and specificity when compared to matched patient upper respiratory specimens. We also evaluated the analytical sensitivity of the platform and determined the limit of detection of the assay to be 1562.5 copies/ml. Furthermore, across the five individual target components of this assay, there was a range in analytic sensitivities for each target with the N2 target being the most sensitive. Overall, this system also demonstrated comparable performance when compared to the detection of SARS-CoV-2 RNA in saliva by the cobas® 6800/8800 SARS-CoV-2 real-time RT-PCR Test (Roche). Together, we demonstrate that saliva represents an appropriate matrix for SARS-CoV-2 detection on the novel Agena system as well as on a conventional real-time RT-PCR assay. We conclude that the MassARRAY® system is a sensitive and reliable platform for SARS-CoV-2 detection in saliva, offering scalable throughput in a large variety of clinical laboratory settings.


Subject(s)
COVID-19 Nucleic Acid Testing/standards , COVID-19/diagnosis , Diagnostic Tests, Routine/standards , RNA, Viral/genetics , SARS-CoV-2/genetics , Saliva/virology , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/standards , Benchmarking , COVID-19/virology , COVID-19 Nucleic Acid Testing/instrumentation , COVID-19 Nucleic Acid Testing/methods , Diagnostic Tests, Routine/instrumentation , Diagnostic Tests, Routine/methods , Humans , Limit of Detection , Nasopharynx/virology , Specimen Handling/standards , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/instrumentation , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods
14.
Nat Commun ; 12(1): 1087, 2021 02 17.
Article in English | MEDLINE | ID: covidwho-1333934

ABSTRACT

The introduction of immune checkpoint inhibitors has demonstrated significant improvements in survival for subsets of cancer patients. However, they carry significant and sometimes life-threatening toxicities. Prompt prediction and monitoring of immune toxicities have the potential to maximise the benefits of immune checkpoint therapy. Herein, we develop a digital nanopillar SERS platform that achieves real-time single cytokine counting and enables dynamic tracking of immune toxicities in cancer patients receiving immune checkpoint inhibitor treatment - broader applications are anticipated in other disease indications. By analysing four prospective cytokine biomarkers that initiate inflammatory responses, the digital nanopillar SERS assay achieves both highly specific and highly sensitive cytokine detection down to attomolar level. Significantly, we report the capability of the assay to longitudinally monitor 10 melanoma patients during immune inhibitor blockade treatment. Here, we show that elevated cytokine concentrations predict for higher risk of developing severe immune toxicities in our pilot cohort of patients.


Subject(s)
Immunotherapy/methods , Melanoma/therapy , Monitoring, Immunologic/methods , Spectrum Analysis, Raman/methods , Chemokine CX3CL1/immunology , Chemokine CX3CL1/metabolism , Cohort Studies , Cytokines/immunology , Cytokines/metabolism , Granulocyte Colony-Stimulating Factor/immunology , Granulocyte Colony-Stimulating Factor/metabolism , Granulocyte-Macrophage Colony-Stimulating Factor/immunology , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Humans , Immune Checkpoint Inhibitors/adverse effects , Immune Checkpoint Inhibitors/immunology , Immune Checkpoint Inhibitors/therapeutic use , Ipilimumab/adverse effects , Ipilimumab/immunology , Ipilimumab/therapeutic use , Melanoma/immunology , Melanoma/metabolism , Microscopy, Confocal/methods , Pilot Projects , Reproducibility of Results
15.
Transbound Emerg Dis ; 68(4): 1995-2004, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1331772

ABSTRACT

This study reports outbreak of a new disease caused by Staphylococcus pseudintermedius (S. pseudintermedius) in raccoon dogs. The disease occurred in a breeding farm of raccoon dogs in Guan County of Shandong Province in China in August of 2019. 47% (425/896) of the raccoon dogs showed some abnormal symptoms; 17.6% (75/425) of which had severe skin and soft tissue infections (SSTIs), dyspnoea and severe pathological lesions in lungs, livers, etc; and 4.2% (18/425) of which died within 4 weeks. The pathogen of the disease was identified as S. pseudintermedius by mass spectrometer detection, animal pathogenicity tests, microscopic examination and biochemical reaction tests. Its nucleotide homology of 16S rRNA gene was 100% with that of other published strains, and its genotype was between the American and Brazilian strains from other animals. The isolated S. pseudintermedius strain from the diseased raccoon dogs could cause ulceration and suppuration in the skins and severe pathological lesions not only in raccoon dogs, but also in mice; and it is confirmed as a methicillin-resistant S. pseudintermedius (MRSP) strain by the amplification of mecA gene; and 12 sensitive drugs were screened by drug sensitivity tests. Full attention should be paid to the great economic loss and the potential zoonotic risk caused by the S. pseudintermedius in raccoon dogs, and this study can provide a reference for the clinical diagnosis and treatment of this new disease.


Subject(s)
Dog Diseases , Raccoon Dogs , Staphylococcal Infections , Animals , Anti-Bacterial Agents/pharmacology , Disease Outbreaks/veterinary , Dog Diseases/epidemiology , Dogs , Mice , RNA, Ribosomal, 16S , Rodent Diseases , Staphylococcal Infections/epidemiology , Staphylococcal Infections/veterinary , Staphylococcus
16.
Nanomaterials (Basel) ; 10(8)2020 Jul 31.
Article in English | MEDLINE | ID: covidwho-1320600

ABSTRACT

A wearable and deformable graphene-based field-effect transistor biosensor is presented that uses aptamer-modified graphene as the conducting channel, which is capable of the sensitive, consistent and time-resolved detection of cytokines in human biofluids. Based on an ultrathin substrate, the biosensor offers a high level of mechanical durability and consistent sensing responses, while conforming to non-planar surfaces such as the human body and withstanding large deformations (e.g., bending and stretching). Moreover, a nonionic surfactant is employed to minimize the nonspecific adsorption of the biosensor, hence enabling cytokine detection (TNF-α and IFN-γ, significant inflammatory cytokines, are used as representatives) in artificial tears (used as a biofluid representative). The experimental results demonstrate that the biosensor very consistently and sensitively detects TNF-α and IFN-γ, with limits of detection down to 2.75 and 2.89 pM, respectively. The biosensor, which undergoes large deformations, can thus potentially provide a consistent and sensitive detection of cytokines in the human body.

17.
Vox Sang ; 116(6): 673-681, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1319364

ABSTRACT

BACKGROUND AND OBJECTIVES: During the ongoing pandemic of COVID-19, SARS-CoV-2 RNA was detected in plasma and platelet products from asymptomatic blood donors, raising concerns about potential risk of transfusion transmission, also in the context of the current therapeutic approach utilizing plasma from convalescent donors. The objective of this study was to assess the efficacy of amotosalen/UVA light treatment to inactivate SARS-CoV-2 in human plasma to reduce the risk of potential transmission through blood transfusion. METHODS: Pools of three whole-blood-derived human plasma units (630-650 ml) were inoculated with a clinical SARS-CoV-2 isolate. Spiked units were treated with amotosalen/UVA light (INTERCEPT Blood System™) to inactivate SARS-CoV-2. Infectious titres and genomic viral load were assessed by plaque assay and real-time quantitative PCR. Inactivated samples were subject to three successive passages on permissive tissue culture to exclude the presence of replication-competent viral particles. RESULTS: Inactivation of infectious viral particles in spiked plasma units below the limit of detection was achieved by amotosalen/UVA light treatment with a mean log reduction of >3·32 ± 0·2. Passaging of inactivated samples on permissive tissue showed no viral replication even after 9 days of incubation and three passages, confirming complete inactivation. The treatment also inhibited NAT detection by nucleic acid modification with a mean log reduction of 2·92 ± 0·87 PFU genomic equivalents. CONCLUSION: Amotosalen/UVA light treatment of SARS-CoV-2 spiked human plasma units efficiently and completely inactivated >3·32 ± 0·2 log of SARS-CoV-2 infectivity, showing that such treatment could minimize the risk of transfusion-related SARS-CoV-2 transmission.


Subject(s)
Furocoumarins/pharmacology , Plasma/virology , SARS-CoV-2/drug effects , SARS-CoV-2/radiation effects , Ultraviolet Therapy , Virus Inactivation , COVID-19/prevention & control , COVID-19/transmission , Humans , Transfusion Reaction/prevention & control , Treatment Outcome
18.
Analyst ; 146(12): 3908-3917, 2021 Jun 14.
Article in English | MEDLINE | ID: covidwho-1319050

ABSTRACT

The pandemic outbreak of the 2019 coronavirus disease (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is still spreading rapidly and poses a great threat to human health. As such, developing rapid and accurate immunodiagnostic methods for the identification of infected persons is needed. Here, we proposed a simple but sensitive on-site testing method based on spike protein-conjugated quantum dot (QD) nanotag-integrated lateral flow immunoassay (LFA) to simultaneously detect SARS-CoV-2-specific IgM and IgG in human serum. Advanced silica-core@dual QD-shell nanocomposites (SiO2@DQD) with superior luminescence and stability were prepared to serve as fluorescent nanotags in the LFA strip and guarantee high sensitivity and reliability of the assay. The performance of the SiO2@DQD-strip was fully optimized and confirmed by using 10 positive serum samples from COVID-19 patients and 10 negative samples from patients with other respiratory diseases. The practical clinical value of the assay was further evaluated by testing 316 serum samples (114 positive and 202 negative samples). The overall detection sensitivity and specificity reached 97.37% (111/114) and 95.54% (193/202), respectively, indicating the huge potential of our proposed method for the rapid and accurate detection of SARS-CoV-2-infected persons and asymptomatic carriers.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Antibodies, Viral , Humans , Immunoassay , Immunoglobulin G , Immunoglobulin M , Reproducibility of Results , SARS-CoV-2 , Sensitivity and Specificity , Silicon Dioxide
19.
J Am Med Inform Assoc ; 28(7): 1548-1554, 2021 Jul 14.
Article in English | MEDLINE | ID: covidwho-1310932

ABSTRACT

OBJECTIVE: Due to the COVID-19 pandemic, our daily habits have suddenly changed. Gatherings are forbidden and, even when it is possible to leave the home for health or work reasons, it is necessary to wear a face mask to reduce the possibility of contagion. In this context, it is crucial to detect violations by people who do not wear a face mask. MATERIALS AND METHODS: For these reasons, in this article, we introduce a method aimed to automatically detect whether people are wearing a face mask. We design a transfer learning approach by exploiting the MobileNetV2 model to identify face mask violations in images/video streams. Moreover, the proposed approach is able to localize the area related to the face mask detection with relative probability. RESULTS: To asses the effectiveness of the proposed approach, we evaluate a dataset composed of 4095 images related to people wearing and not wearing face masks, obtaining an accuracy of 0.98 in face mask detection. DISCUSSION AND CONCLUSION: The experimental analysis shows that the proposed method can be successfully exploited for face mask violation detection. Moreover, we highlight that it is working also on device with limited computational capability and it is able to process in real time images and video streams, making our proposal applicable in the real world.


Subject(s)
Automated Facial Recognition , COVID-19 , Deep Learning , Masks , Datasets as Topic , Female , Humans , Male
20.
Immunology ; 164(1): 135-147, 2021 09.
Article in English | MEDLINE | ID: covidwho-1295026

ABSTRACT

Detecting antibody responses during and after SARS-CoV-2 infection is essential in determining the seroepidemiology of the virus and the potential role of antibody in disease. Scalable, sensitive and specific serological assays are essential to this process. The detection of antibody in hospitalized patients with severe disease has proven relatively straightforward; detecting responses in subjects with mild disease and asymptomatic infections has proven less reliable. We hypothesized that the suboptimal sensitivity of antibody assays and the compartmentalization of the antibody response may contribute to this effect. We systematically developed an ELISA, optimizing different antigens and amplification steps, in serum and saliva from non-hospitalized SARS-CoV-2-infected subjects. Using trimeric spike glycoprotein, rather than nucleocapsid, enabled detection of responses in individuals with low antibody responses. IgG1 and IgG3 predominate to both antigens, but more anti-spike IgG1 than IgG3 was detectable. All antigens were effective for detecting responses in hospitalized patients. Anti-spike IgG, IgA and IgM antibody responses were readily detectable in saliva from a minority of RT-PCR confirmed, non-hospitalized symptomatic individuals, and these were mostly subjects who had the highest levels of anti-spike serum antibodies. Therefore, detecting antibody responses in both saliva and serum can contribute to determining virus exposure and understanding immune responses after SARS-CoV-2 infection.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Immunoglobulin M/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antigens, Viral/immunology , COVID-19/blood , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay , Humans , Saliva
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