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1.
Iran J Pathol ; 19(2): 170-176, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39118794

RESUMEN

Background & Objective: Providing equitable access to good quality, timely, and affordable laboratory testing has always been a top priority for the Ministry of Health and Medical Education (MoH-ME) and the Reference Health Laboratory (RHL). Considering the significant role of medical laboratories in disease surveillance, RHL developed a strategic plan to manage laboratory services during the COVID-19 pandemic based on the "Strategic Framework for strengthening health laboratory services, 2016-2020" proposed by the World Health Organization (WHO). This article describes the steps taken to establish the strategic framework in Iran. Methods: Firstly, a National Laboratory Committee was formed in MoH-ME and a situation analysis was conducted to explore the strengths, weaknesses, opportunities, and threats in different components of our laboratory system. Gaps and resources needed to address those gaps were determined; then, RHL outlined operational processes and mechanisms for monitoring the activities. Results: The WHO strategic roadmap and its six strategic goals concerning leadership, quality, human resources, safety and security, laboratory networking, and rational use of laboratory testing, helped us to promote national laboratory services in accordance with health system requirements in the COVID-19 pandemic. Conclusion: The establishment of a national molecular laboratory network with more than 500 laboratories from different sectors may result in timely access to countrywide laboratory services and would be beneficial for future COVID-19 and/or other viral outbreaks. Continual evaluation of the COVID-19 laboratories' performance, production of PCR test kits by the local manufacturers, and development of a platform for virtual training would be other accomplishments that Iran achieved in coping with the recent pandemic.

2.
Indian J Med Microbiol ; 51: 100687, 2024 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-39074768

RESUMEN

PURPOSE: The study aims to compare random-access NeuMoDx values with artus qPCR values to validate the accuracy of NeuMoDx as an alternative to qPCR and provide an equation to convert copies/ml to IU/ml measurements. METHODS: A total of 95 samples, including 61 transplant patient samples (n = 23 urine, n = 38 plasma) as the study group, 28 BKPyV-free samples as the control group, and six quality control samples, were included. One-Way ANOVA, Pearson correlation, Bland-Altman, Passing-Bablok, Deming regression analyses were used for statistical evaluation. RESULTS: Of 95 samples, 46 (48 %) were positive with NeuMoDx, while 40 (42 %) were positive with artus qPCR. Both techniques were statistically similar (p > 0.05). Deming correlation analysis (r = 0.9590), Passing Bablok and Bland Altman analyses demonstrated a strong correlation between NeuMoDx and artus values. The equation that provides the conversion between NeuMoDx and artus qPCR values was NeuMoDx= (1.12965 x artus qPCR) - 0.55016. BKPyV infections remain a concern for transplant patients globally, and effective new diagnostic methods are required. CONCLUSIONS: Consistency between the results of NeuMoDx and qPCR confirms that NeuMoDx may be a valuable alternative for detecting BKPyV to prevent viral propagation. Our findings may allow converting copy/ml results to IU/ml for diagnosing and monitoring BKPyV infections in transplant patients.

3.
BMC Pulm Med ; 24(1): 366, 2024 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-39080682

RESUMEN

BACKGROUND: Severe COVID-19 carries a high morbidity and mortality. Previous studies have shown an association between COVID-19 severity and SARS-CoV-2 viral load (VL). We sought to measure VL in multiple compartments (urine, plasma, lower respiratory tract) in patients admitted to the intensive care unit (ICU) with severe COVID-19 pneumonia and correlate with clinical outcomes. METHODS: Plasma, urine, and endotracheal aspirate (ETA) samples were obtained on days 1, 3, 7, 14, and 21 from subjects admitted to the ICU with severe COVID-19. VL was measured via reverse transcriptase polymerase chain reaction. Clinical data was collected from the electronic health record. Grouped comparisons were performed using Student's t-test or 1-way ANOVA. Linear regression was used to correlate VL from different compartments collected at the same time. Logistic regression was performed to model ventilator-freedom at 28 days as a function of peak plasma VL. RESULTS: We enrolled 57 subjects with severe COVID-19 and measured VL in plasma (n = 57), urine (n = 25), and ETA (n = 34). Ventilator-associated pneumonia developed in 63% of subjects. 49% of subjects were viremic on study day 1. VL in plasma and ETA both significantly decreased by day 14 (P < 0.05), and the two were weakly correlated on study day 1 (P = 0.0037, r2 = 0.2343) and on all study days (P < 0.001, r2 = 0.2211). VL were not detected in urine. While no associations were observed with peak ETA VL, subjects with higher peak plasma VL experienced a greater number of respiratory complications, including ventilator-associated pneumonia and fewer ventilator-free and hospital-free days. There was no association between VL in either plasma or ETA and mortality. In viremic patients, plasma VL was significantly lower in subjects that were ICU-free and ventilator-free (P < 0.05), with trends noted for hospital-freedom, ventilator-associated pneumonia, and survival to discharge (P < 0.1). By logistic regression, plasma VL was inversely associated with ventilator-freedom at 28 days (odds ratio 0.14, 95% confidence interval 0.02-0.50). CONCLUSIONS: Elevated SARS-CoV-2 VL in the plasma but not in the lower respiratory tract is a novel biomarker in severe COVID-19 for respiratory complications.


Asunto(s)
COVID-19 , Unidades de Cuidados Intensivos , SARS-CoV-2 , Carga Viral , Viremia , Humanos , COVID-19/complicaciones , Masculino , Femenino , Persona de Mediana Edad , Anciano , Índice de Severidad de la Enfermedad , Neumonía Asociada al Ventilador/epidemiología , Neumonía Asociada al Ventilador/virología , Adulto
4.
Food Chem ; 460(Pt 1): 140573, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-39053273

RESUMEN

Loop-mediated isothermal amplification (LAMP) is a rapid and sensitive nucleic acid testing method for pathogen detection, yet the absence of a straightforward readout strategy remains challenging. We've successfully designed polyethyleneimine-stabilized gold nanoclusters (PEI-AuNCs) as a cationic AuNCs indicator tailored for distinguishing LAMP results, enabling direct visual inspection under UV light. Positive LAMP reactions with PEI-AuNCs, in combination with magnesium pyrophosphate crystals, yield red-fluorescent bulk precipitates visible to the naked eye. To address contamination concerns, we introduced a one-pot reaction by incorporating AuNCs into the lid recess. This one-pot LAMP assay demonstrates exceptional detection capability, identifying Salmonella enterica at concentrations as low as 101 CFU/mL within approximately 50 min, excluding nucleic acid extraction. The platform's versatility, achieved through customizable primers, positions it as a promising molecular diagnostic tool for rapid and visual pathogen detection across scientific disciplines.

5.
Talanta ; 278: 126487, 2024 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-39002258

RESUMEN

Early screening for pathogens is crucial during pandemic outbreaks. Nucleic acid testing (NAT) is a valuable method for keeping pathogens from spreading. However, the long detection time and large size of the instruments involved significantly limited the efficiency of detection. This work described an integrated NAT microsensor that facilitated rapid and extremely sensitive detection based on nucleic acid amplification (NAA) on a chip. The biochip consisted of two layers incorporating a heater, a thermometer, an interdigital electrode (IDE) and a reaction chamber. The Pt electrode based heater and thermometer were utilized to maintain a specific temperature for the sample in the chamber. The thermometer exhibited a good linear correlation with a sensitivity of 9.36 Ω/°C and the heater achieved a heating efficiency of approximately 6.5 °C/s. Multiple ions were released during NAA, resulting in a decrease in the impedance of the amplification system solution. A large signal of impedance was generated by the released ions due to its linear correlation with the logarithm of the ion concentration. With this detection principle, IDE was employed for real-time monitoring of the in-chip reaction system impedance and NAA process. Specific nucleic acids from two pathogens (SARS-CoV-2, Vibrio vulnificus) were detected with this microsensor. The samples were qualitatively analyzed on microchip within 3 min, with a limit of detection (LOD) of 103 copies/µL. The proposed sensor presented several advantages, including reduced NAT time and increased sensitivity. Consequently, it has shown significant potential in rapid and high-quality nucleic acid testing for the field of epidemic prevention.


Asunto(s)
Técnicas Biosensibles , Impedancia Eléctrica , Técnicas de Amplificación de Ácido Nucleico , SARS-CoV-2 , Técnicas Biosensibles/métodos , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/genética , Técnicas de Amplificación de Ácido Nucleico/métodos , Humanos , Límite de Detección , Electrodos , Dispositivos Laboratorio en un Chip , COVID-19/diagnóstico , COVID-19/virología , Prueba de Ácido Nucleico para COVID-19/métodos , Prueba de Ácido Nucleico para COVID-19/instrumentación , ARN Viral/análisis , ARN Viral/genética
6.
Sensors (Basel) ; 24(13)2024 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-39001045

RESUMEN

Nucleic acid tests are key tools for the detection and diagnosis of many diseases. In many cases, the amplification of the nucleic acids is required to reach a detectable level. To make nucleic acid amplification tests more accessible to a point-of-care (POC) setting, isothermal amplification can be performed with a simple heating source. Although these tests are being performed in bulk reactions, the quantification is not as accurate as it would be with digital amplification. Here, we introduce the use of the vibrating sharp-tip capillary for a simple and portable system for tunable on-demand droplet generation. Because of the large range of droplet sizes possible and the tunability of the vibrating sharp-tip capillary, a high dynamic range (~2 to 6000 copies/µL) digital droplet loop-mediated isothermal amplification (ddLAMP) system has been developed. It was also noted that by changing the type of capillary on the vibrating sharp-tip capillary, the same mechanism can be used for simple and portable DNA fragmentation. With the incorporation of these elements, the present work paves the way for achieving digital nucleic acid tests in a POC setting with limited resources.


Asunto(s)
Técnicas de Amplificación de Ácido Nucleico , Técnicas de Amplificación de Ácido Nucleico/métodos , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Técnicas Biosensibles/métodos , Técnicas Biosensibles/instrumentación , Vibración , Sistemas de Atención de Punto , Humanos , Ácidos Nucleicos/análisis , ADN/análisis , ADN/genética , ADN/química
7.
Adv Sci (Weinh) ; 11(28): e2403120, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38728591

RESUMEN

The DNA-guided (gDNA) Argonaute from Thermus thermophilus (TtAgo) has little potential for nucleic acid detection and gene editing due to its poor dsDNA cleavage activity at relatively low temperature. Herein, the dsDNA cleavage activity of TtAgo is enhanced by using 2'-fluorine (2'F)-modified gDNA and developes a novel nucleic acid testing strategy. This study finds that the gDNA with 2'F-nucleotides at the 3'-end (2'F-gDNA) can promote the assembly of the TtAgo-guide-target ternary complex significantly by increasing its intermolecular force to target DNA and TtAgo, thereby providing ≈40-fold activity enhancement and decreasing minimum reaction temperature from 65 to 60 °C. Based on this outstanding advance, a novel nucleic acid testing strategy is proposed, termed FAST, which is performed by using the 2'F-gDNA/TtAgo for target recognition and combining it with Bst DNA polymerase for nucleic acid amplification. By integrating G-quadruplex and Thioflavin T, the FAST assay achieves one-pot real-time fluorescence analysis with ultra-sensitivity, providing a limit of detection up to 5 copies (20 µL reaction mixture) for miR-21 detection. In summary, an atom-modification-based strategy has been developed for enhancing the cleavage activity of TtAgo efficiently, thereby improving its practicability and establishing a TtAgo-based nucleic acid testing technology with ultra-sensitivity and high-specificity.


Asunto(s)
ADN , Thermus thermophilus , Thermus thermophilus/genética , Thermus thermophilus/metabolismo , ADN/genética , ADN/metabolismo , ADN/química , Proteínas Argonautas/metabolismo , Proteínas Argonautas/genética , Ácidos Nucleicos/metabolismo , Ácidos Nucleicos/genética , Flúor/química
8.
Anal Chim Acta ; 1311: 342720, 2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-38816155

RESUMEN

BACKGROUND: The monkeypox virus (MPXV) is a linear double-stranded DNA virus with a large genome that causes tens of thousands of infections and hundreds of deaths in at least 40 countries and regions worldwide. Therefore, timely and accurate diagnostic testing could be an important measure to prevent the ongoing spread of MPXV and widespread epidemics. RESULTS: Here, we designed multiple sets of primers for the target region of MPXV for loop-mediated isothermal amplification (LAMP) detection and identified the optimal primer set. Then, the specificity in fluorescent LAMP detection was verified using the plasmids containing the target gene, pseudovirus and other DNA/RNA viruses. We also evaluated the sensitivity of the colorimetric LAMP detection system using the plasmid and pseudovirus samples, respectively. Besides, we used monkeypox pseudovirus to simulate real samples for detection. Subsequent to the establishment and introduction of a magnetic beads (MBs)-based nucleic acid extraction technique, an integrated device was developed, characterized by rapidity, high sensitivity, and remarkable specificity. This portable system demonstrated a visual detection limit of 137 copies/mL, achieving sample-to-answer detection within 1 h. SIGNIFICANCE: The device has the advantages of integration, simplicity, miniaturization, and visualization, which help promote the realization of accurate, rapid, portable, and low-cost testing. Meanwhile, this platform could facilitate efficient, cost-effective and easy-operable point-of-care testing (POCT) in diverse resource-limited settings in addition to the laboratory.


Asunto(s)
Colorimetría , Monkeypox virus , Técnicas de Amplificación de Ácido Nucleico , Colorimetría/métodos , Colorimetría/instrumentación , Técnicas de Amplificación de Ácido Nucleico/métodos , Monkeypox virus/genética , Monkeypox virus/aislamiento & purificación , Límite de Detección , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Diagnóstico Molecular/instrumentación
9.
Biosens Bioelectron ; 259: 116403, 2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-38776802

RESUMEN

Robust encapsulation and controllable release of biomolecules have wide biomedical applications ranging from biosensing, drug delivery to information storage. However, conventional biomolecule encapsulation strategies have limitations in complicated operations, optical instability, and difficulty in decapsulation. Here, we report a simple, robust, and solvent-free biomolecule encapsulation strategy based on gallium liquid metal featuring low-temperature phase transition, self-healing, high hermetic sealing, and intrinsic resistance to optical damage. We sandwiched the biomolecules with the solid gallium films followed by low-temperature welding of the films for direct sealing. The gallium can not only protect DNA and enzymes from various physical and chemical damages but also allow the on-demand release of biomolecules by applying vibration to break the liquid gallium. We demonstrated that a DNA-coded image file can be recovered with up to 99.9% sequence retention after an accelerated aging test. We also showed the practical applications of the controllable release of bioreagents in a one-pot RPA-CRISPR/Cas12a reaction for SARS-COV-2 screening with a low detection limit of 10 copies within 40 min. This work may facilitate the development of robust and stimuli-responsive biomolecule capsules by using low-melting metals for biotechnology.


Asunto(s)
Técnicas Biosensibles , Transición de Fase , SARS-CoV-2 , Técnicas Biosensibles/métodos , SARS-CoV-2/aislamiento & purificación , COVID-19/virología , Galio/química , Humanos , ADN/química , Sistemas CRISPR-Cas , Cápsulas/química
10.
J Clin Virol ; 173: 105688, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38776575

RESUMEN

Respiratory pathogens, such as SARS-CoV-2 and influenza A/B, can cause severe illnesses in susceptible individuals. This research evaluated a novel digital microfluidic point-of-care testing platform designed to detect 23 pathogens, comparing its performance to conventional laboratory-based nucleic acid tests. The platform integrates nucleic acid extraction and amplification processes for rapid detection with only 2 min of hands-on time. Performance assays demonstrated that the platform has high sensitivity (87 %-100 %) and specificity (99 %-100 %) for the detection of the evaluated 3 viruses. Additionally, the platform can be adapted for the detection of other respiratory pathogens, aiding in the early diagnosis of respiratory diseases, identifying the source of an outbreak or epidemic, and curbing the spread of the disease.


Asunto(s)
COVID-19 , Virus de la Influenza A , Virus de la Influenza B , Gripe Humana , Pruebas en el Punto de Atención , SARS-CoV-2 , Sensibilidad y Especificidad , Humanos , Gripe Humana/diagnóstico , Gripe Humana/virología , COVID-19/diagnóstico , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/genética , Virus de la Influenza B/aislamiento & purificación , Virus de la Influenza B/genética , Virus de la Influenza A/aislamiento & purificación , Virus de la Influenza A/genética , Microfluídica/métodos , Microfluídica/instrumentación , Sistemas de Atención de Punto
11.
Front Public Health ; 12: 1366431, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38601498

RESUMEN

Background: When employing the transcription-mediated amplification method for screening blood donors, there are some non-discriminatory reactive results which are screening assay reactive but HBV-DNA discriminatory assay negative. This raises concerns regarding the possibility of false positives among donors, which may lead to permanent deferral of blood donors and affect blood supply. This study aimed to elucidate the infection status of these non-discriminatory reactive blood donors and develop and validate a model to predict individualized hepatitis B status to establish an optimal screening strategy. Methods: Supplementary tests were conducted on initial non-discriminating reactive donations to determine their HBV infection status, including repeat testing, viral load, serological marker detection, and follow-up. Primary clinical variables of the donors were recorded. Based on the Akaike information criterion, a stepwise forward algorithm was used to identify the predictive factors for information and construct a predictive model. The optimal screening strategy was determined through cost-effectiveness analysis. Results: At the Blood Center of Zhejiang Province, 435 cases of initial non-discriminatory reactive donations were collected over two successive periods and sub-categorized through repeated testing into the following three groups: non-repeated positive group, non-discriminated positive group, and non-repeated HBV-DNA positive group. The HBV discriminatory rate increased after repeated testing (110/435, 25.29%). According to supplementary tests, the HBV-DNA positivity rate was 65.52% (285/435), and occult HBV infection was a significantly different among groups (χ2 = 93.22, p < 0.01). The HBV serological markers and viral load in the non-repeated positive group differed from those in the other two groups, with a lower viral load and a higher proportion of false positives. The predictive model constructed using a stepwise forward algorithm exhibited high discrimination, good fit, high calibration, and effectiveness. A cost-effectiveness analysis indicated that utilizing repeated discriminatory testing and the predictive model is an extremely beneficial screening approach for non-discriminatory reactive blood donors. Conclusion: Nearly two-third (65.52%) of the non-discriminatory reactive blood donors were HBV-DNA positive. Our innovative approach of constructing a predictive model as a supplementary screening strategy, combined with repeated discriminatory experiments, can effectively identify the infection status of non-discriminatory reactive blood donors, thereby increasing the safety of blood transfusions.


Asunto(s)
Virus de la Hepatitis B , Hepatitis B , Humanos , Virus de la Hepatitis B/genética , Hepatitis B/diagnóstico , Hepatitis B/epidemiología , Hepatitis B/prevención & control , Donantes de Sangre , ADN Viral/análisis , ADN Viral/genética , China/epidemiología
12.
Adv Sci (Weinh) ; 11(21): e2309557, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38516754

RESUMEN

Digital PCR (dPCR) holds immense potential for precisely detecting nucleic acid markers essential for personalized medicine. However, its broader application is hindered by high consumable costs, complex procedures, and restricted multiplexing capabilities. To address these challenges, an all-in-one dPCR system is introduced that eliminates the need for microfabricated chips, offering fully automated operations and enhanced multiplexing capabilities. Using this innovative oscillation-induced droplet generation technique, OsciDrop, this system supports a comprehensive dPCR workflow, including precise liquid handling, pipette-based droplet printing, in situ thermocycling, multicolor fluorescence imaging, and machine learning-driven analysis. The system's reliability is demonstrated by quantifying reference materials and evaluating HER2 copy number variation in breast cancer. Its multiplexing capability is showcased with a quadruplex dPCR assay that detects key EGFR mutations, including 19Del, L858R, and T790M in lung cancer. Moreover, the digital stepwise melting analysis (dSMA) technique is introduced, enabling high-multiplex profiling of seven major EGFR variants spanning 35 subtypes. This innovative dPCR system presents a cost-effective and versatile alternative, overcoming existing limitations and paving the way for transformative advances in precision diagnostics.


Asunto(s)
Neoplasias de la Mama , Humanos , Neoplasias de la Mama/genética , Neoplasias de la Mama/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Reproducibilidad de los Resultados , Reacción en Cadena de la Polimerasa/métodos , Patología Molecular/métodos , Receptores ErbB/genética , Variaciones en el Número de Copia de ADN/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/diagnóstico , Receptor ErbB-2/genética , Reacción en Cadena de la Polimerasa Multiplex/métodos , Mutación , Femenino
13.
Diagn Microbiol Infect Dis ; 109(2): 116240, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38547799

RESUMEN

Occult HBV infection (OBI) remains a potential threat for blood safety. The prevalence of OBI was investigated in a blood donation center of Chinese PLA General Hospital to improve HBV blood safety. 229446 samples from blood donors were screened by two different enzyme-linked immunosorbent assay (ELISA) kits. 78 samples were HBV DNA positive among 212134 ELISA nonreactive donor samples. The prevalence of OBI was 0.04% (76/212134). Ten samples of OBI were permitted by the donors' content for further research, and all of these were below 200IU/mL, and six of these were below 20IU/mL(6/10,60%). Genotype B and genotype C was 20% (2/10) and 80% (8/10), respectively. 16 amino acid mutations were detected in the S region of OBI, included three mutations in MHR region of S. The prevalence of OBI is rare in this donation center. These mutations we found may contribute to the multifactorial occurrence of OBI.


Asunto(s)
Donantes de Sangre , ADN Viral , Genotipo , Virus de la Hepatitis B , Hepatitis B , Humanos , Donantes de Sangre/estadística & datos numéricos , Hepatitis B/epidemiología , Hepatitis B/virología , Prevalencia , Virus de la Hepatitis B/genética , Virus de la Hepatitis B/aislamiento & purificación , Beijing/epidemiología , Masculino , Adulto , Femenino , ADN Viral/genética , ADN Viral/sangre , Persona de Mediana Edad , Mutación , Adulto Joven , Ensayo de Inmunoadsorción Enzimática , China/epidemiología , Adolescente
14.
Qual Health Res ; : 10497323241233438, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38477095

RESUMEN

In the context of the global COVID-19 pandemic, this study focuses on Chinese university students, employing graphic elicitation as a qualitative research method to analyze their hand-drawn paintings and related descriptions. Augmented by A/r/tography and metacognitive methods, the research aims to unveil the participants' collective memory, as well as the perspectives and responses of these students to policies related to the pandemic. By specifically examining this particular demographic, the study incorporates Fairclough's ethical theory, applying deontological ethics, consequentialist ethics, and virtue ethics to establish a comprehensive framework for evaluating adjustments to pandemic response policies. This research not only enhances our understanding of how these university students perceive and adapt to COVID-19 policies but also provides valuable insights for decision-makers. The particular methodology, combining graphic elicitation and metacognitive research, contributes to policy assessment and ethical analysis, offering a nuanced perspective on the interplay between individual perceptions, policy responses, and ethical considerations amid the complexities of a public health crisis.

15.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 55(1): 183-189, 2024 Jan 20.
Artículo en Chino | MEDLINE | ID: mdl-38322527

RESUMEN

Objective: To develop a catalytic hairpin assembly (CHA)-based fluorescent assay for the detection of the target RNA of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), so as to realize the rapid nucleic acid testing of SARS-CoV-2. Methods: A 24-nt segment of the SARS-CoV-2 nucleocapsid protein gene (N gene, NC_045512.2) was chosen as the target RNA and the hairpin motif 1 (H1) and hairpin motif 2 (H2) were designed based on the principle of CHA reaction. The H1 motif was labelled with a fluorophore group as well as a quencher group. When the target RNA was added to the hairpin motifs, CHA reaction was triggered at room temperature (25 ℃), which led to the amplification of fluorescence signal, thereby enabling the rapid detection of the target RNA. After the optimization of the hairpin motifs and the experimental conditions, the sensitivity and the specificity of the testing method were measured to evaluate its performance. Results: We successfully constructed a CHA-based fluorescent assay specifically for the target RNA of SARS-CoV-2. With this method, testing could be completed at room temperature within 30 min. This testing method exhibited excellent specificity and could be used to accurately distinguish the perfectly-matched target RNA from the target RNA with single-base mutations. In addition, the testing method demonstrated good sensitivity, with a detection limit of 50 pmol/L. Conclusion: The proposed assay enables the simple and rapid detection of the SARS-CoV-2 target RNA with excellent sensitivity and specificity, showing great promise for further optimization and subsequent clinical application for the rapid detection of SARS-CoV-2 nucleic acid.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , Sensibilidad y Especificidad , ARN , Técnicas de Amplificación de Ácido Nucleico/métodos
16.
Heliyon ; 10(1): e23700, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38187298

RESUMEN

In the past three years, waves of COVID-19 infections have emerged one after another, and may enter a small-scale wave-like recurrent epidemic pattern in the future. When COVID-19 infections occur in small-scale, how to efficiently detect and prevent the disease has become the main problem. In this study, based on the characteristics of the Omicron variant and China's pandemic prevention and control strategies, the following three nucleic acid testing scenarios were simulated: scenario 1 (baseline scenario) included conducting nucleic acid testing at administrative region; scenario 2 included conducting nucleic acid testing at the community; and scenario 3 included conducting nucleic acid testing at the health facility closest to households. The model calibration showed that the baseline scenario was consistent with the actual transmission scenario of the disease. The simulation results revealed that compared with scenario 1, the cumulative cases in scenarios 2 and 3 were reduced by 9.52 % and 46.83 %, respectively. Compared with scenario 2, the cumulative cases in scenario 3 were reduced by 41.23 %. Thus, adopting nucleic acid testing measures at the household level can effectively limit the spread of COVID-19 and should be given a priority when local emergency occurs in the future.

17.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-1024980

RESUMEN

【Objective】 To analyze the correlation between the distribution interval of minipool nucleic acid testing(NAT) positive CT value and the resolution rate, so as to improve the retest model and reduce residual risk of blood transfusion. 【Methods】 The resolution testing results by Cobas S201 system of our blood center from January 2017 to December 2021 were retrospective analyzed, and the retest model was developed based on the distribution interval of CT values. For minipool NAT HBV positive samples from March 2022 to March 2023, synchronous detection was conducted by Cobas S201 and Panther detection system, and the detection results were statistically analyzed. 【Results】 From 2017 to 2021, 474 were minipool NAT positive, among which 324 were HBV positive, accounting for 68.35%. From 2017 to 2020, the proportion of HBV positive per year was significantly higher than that of HCV and HIV(P40, with the resolution rate at 95.8%, 56.5% and 14.8% respectively(P40, 36

18.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-1029944

RESUMEN

A 11-year old female patient with severe thalassemia, receipt a lentivirus-based cell and gene therapy (CGT) therapy in Shenzhen Children′s Hosptial on July 27th, 2021. At the two follow-up visits after discharge, patient were continuously tested positive for HIV screening through HIV Ag/Ab Combo assay (chemiluminescence Immunoassay), and the viral load results of HIV-1 nucleic acid testing (NAT) were both>5 000 copies/ml. The patient can be diagnosed with HIV infection according to the National Guideline for Detection of HIV/AIDS(2020 Revised Edition). The thorough investigation findings and supplementary experiment results indicated that the false-positive HIV-1 NAT results was caused by cross-reactivity between the target sites detected by conventional HIV-1 NAT reagents and the lentiviral vectors fragments integrated into the genome of patient′s hematopoietic stem/progenitor cells. In conclusion, it is important for laboratories to select appropriate HIV-1 NAT testing platforms which won′t cause cross-reactivity for the testing of samples from patients who have been treated with HIV-derived vectors. It is also recommended to design and develop NAT testing platforms with multiple target regions labeled by different fluorescents for HIV NAT supplementation experiment to reduce the risk of false-positive diagnoses of HIV infection.

19.
ACS Sens ; 8(12): 4716-4727, 2023 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-38011515

RESUMEN

Human immunodeficiency virus (HIV) is a significant problem to consider as it can lead to acquired immune deficiency syndrome (AIDS). Fortunately, AIDS is manageable through antiretroviral therapy (ART). However, frequent viral load monitoring is needed to monitor the effectiveness of the therapy. The current reverse transcription-polymerase chain reaction (RT-PCR) viral load monitoring is highly effective, but is challenged by being resource-intensive and inaccessible, and its turnaround time does not meet demand. An unmet need exists for an affordable, rapid, and user-friendly point-of-care device that could revolutionize and ensure therapeutic effectiveness, particularly in resource-limited settings. In this work, we explored a point-of-care HIV viral load device to address this need. This device can perform streamlined plasma separation, viral RNA extraction, and real-time reverse transcription loop-mediated isothermal amplification (RT-LAMP) semiquantitative testing in an ultracompact device. We developed an absorption-based membrane plasma separation method suitable for finger-prick blood samples, achieving an efficiency of 80%. We also designed a syringe-based RNA extraction method for on-site plasma processing with a viral recovery efficiency of 86%. We created a portable device with a smartphone interface for real-time semiquantitative RT-LAMP, which is useful for monitoring viral load. The device uses lyophilized reagents, processed with our lyophilization method, which remain stable for 16 weeks. The device can accurately categorize viral load into low, medium, and high categories with 95% accuracy. We believe this point-of-care HIV self-test device, offering convenience and long-term storage, could aid patients in home-based ART treatment monitoring.


Asunto(s)
Síndrome de Inmunodeficiencia Adquirida , Infecciones por VIH , VIH-1 , Humanos , Sistemas de Atención de Punto , Carga Viral/métodos
20.
Emerg Infect Dis ; 29(12): 2559-2561, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37885051

RESUMEN

We analyzed wastewater samples from 14 aircraft arriving in Denmark directly from China during January 9-February 12, 2023. Wastewater from 11 aircraft was SARS-CoV-2-positive by PCR; 6 predominantly contained BQ.1 and XBB.1 subvariants. Wastewater-based surveillance can contribute to public health monitoring of SARS-CoV-2 and other emerging infectious agents.


Asunto(s)
COVID-19 , Humanos , COVID-19/epidemiología , SARS-CoV-2/genética , Aguas Residuales , China/epidemiología , Aeronaves , Dinamarca/epidemiología
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