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1.
Electron. j. biotechnol ; 52: 21-29, July. 2021. ilus, tab, graf
Article in English | LILACS | ID: biblio-1283484

ABSTRACT

BACKGROUND: Super-paramagnetic iron oxide nanoparticles (SPION) contain a chemotherapeutic drug and are regarded as a promising technique for improving targeted delivery into cancer cells. RESULTS: In this study, the fabrication of 5-fluorouracil (5-FU) was investigated with loaded Dextran (DEXSPION) using the co-precipitation technique and conjugated by folate (FA). These nanoparticles (NPs) were employed as carriers and anticancer compounds against liver cancer cells in vitro. Structural, magnetic, morphological characterization, size, and drug loading activities of the obtained FA-DEX-5-FUSPION NPs were checked using FTIR, VSM, FESEM, TEM, DLS, and zeta potential techniques. The cellular toxicity effect of FA-DEX-5-FU-SPION NPs was evaluated using the MTT test on liver cancer (SNU-423) and healthy cells (LO2). Furthermore, the apoptosis measurement and the expression levels of NF-1, Her-2/neu, c-Raf-1, and Wnt-1 genes were evaluated post-treatment using flow cytometry and RT-PCR, respectively. The obtained NPs were spherical with a suitable dispersity without noticeable aggregation. The size of the NPs, polydispersity, and zeta were 74 ± 13 nm, 0.080 and 45 mV, respectively. The results of the encapsulation efficiency of the nano-compound showed highly colloidal stability and proper drug maintenance. The results indicated that FA-DEX-5-FU-SPION demonstrated a sustained release profile of 5-FU in both phosphate and citrate buffer solutions separately, with higher cytotoxicity against SNU-423 cells than against other cells types. These findings suggest that FA-DEX-SPION NPs exert synergistic effects for targeting intracellular delivery of 5-FU, apoptosis induction, and gene expression stimulation. CONCLUSIONS: The findings proved that FA-DEX-5-FU-SPION presented remarkable antitumor properties; no adverse subsequences were revealed against normal cells.


Subject(s)
Humans , Carcinoma, Hepatocellular/drug therapy , Fluorouracil/administration & dosage , Liver Neoplasms/drug therapy , Polymers , Gene Expression/drug effects , Drug Delivery Systems , Apoptosis/drug effects , Reverse Transcriptase Polymerase Chain Reaction , Delayed-Action Preparations , Nanoparticles/administration & dosage , Magnetite Nanoparticles , Flow Cytometry
2.
Rev. ADM ; 78(2): 90-94, mar.-abr. 2021.
Article in Spanish | LILACS | ID: biblio-1247690

ABSTRACT

La biología molecular tiene mayor afinidad en las áreas de la salud, en odontología su principal aplicación ha sido en la identificación de microorganismos orales patógenos mediante el uso de secuencias genéticas específicas (ácido desoxirribonucleico [DNA], ácido ribonucleico [RNA] y proteínas). Las pruebas a nivel molecular se caracterizan por su rapidez, reproductibilidad, sensibilidad y especificidad de los microorganismos diana. El presente artículo de revisión bibliográfica servirá como herramienta para comprender los principios de las técnicas más destacadas como son: PCR estándar y RT-PCR en tiempo real, PCR con transcriptasa inversa, microarreglos y ensayo por inmunoabsorción ligado a enzimas (ELISA), además de sus ventajas y desventajas respecto a las pruebas convencionales (AU)


Molecular biology has a greater affinity in the areas of health. In dentistry, its main application has been the identification of pathogenic oral microorganisms, through the use of specific genetic sequences (deoxyribonucleic acid [DNA], ribonucleic acid [RNA] and proteins). Molecular tests are characterized by their rapidity, reproducibility, sensitivity and specificity of target microorganisms. This literature review article will serve as a tool to understand the principles of the most prominent techniques such as: Standard PCR, Real-time RT-PCR, Reverse transcriptase PCR, microarrays and Enzyme-linked immunosorbent assay (ELISA), in addition to their advantages and disadvantages with respect to conventional tests (AU)


Subject(s)
Humans , Sensitivity and Specificity , Diagnosis, Oral/methods , Molecular Biology , Mouth Diseases/diagnosis , Enzyme-Linked Immunosorbent Assay , Polymerase Chain Reaction , RNA-Directed DNA Polymerase , Reverse Transcriptase Polymerase Chain Reaction , Databases, Genetic
3.
Braz. arch. biol. technol ; 64: e21210292, 2021. tab, graf
Article in English | LILACS | ID: biblio-1278439

ABSTRACT

Abstract NADPH-cytochromeP450 reductase (CPR) is one of the most important components of the cytochrome P450 enzyme system. In this study, a gene encoding CPR (named EsCPR) was isolated from Eriocheir sinensis using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) methods. Analysis of the nucleotide sequence revealed a cDNA full-length of 3717 bp with an open reading frame of 2046 bp, a 5′-untranslated region of 42 bp, and a long 3′-untryganslated region of 1628bp, which encodes a protein of 681 amino acids with a predicted molecular weight of 30.7 kDa and an estimated pI of 4.82. The mature peptide shares amino acid of E. sinensis identity 82 % - 89 % to the CPR from Penaeus vannamei and Chionoecetes opilio. Tissues and developmental stage-dependent expression of EsCPR mRNA was investigated by real-time quantitative PCR. EsCPR mRNA was markedly expressed in the hepatopancreas and stomach. These results would provide valuable information for further study on the interactions between CPR and cytochrome P450 enzyme systems.


Subject(s)
NADPH-Ferrihemoprotein Reductase , Cloning, Organism , Brachyura , Gene Expression , Reverse Transcriptase Polymerase Chain Reaction
4.
Epidemiol. serv. saúde ; 30(2): e2020722, 2021. graf
Article in English, Portuguese | LILACS | ID: biblio-1249797

ABSTRACT

Objetivo: Analisar como a testagem da população influencia os indicadores de saúde usados para monitorar a pandemia de COVID-19 nos 50 países com maior número de casos diagnosticados. Métodos: Estudo ecológico sobre dados secundários, extraídos em 19/08/2020. Foram calculadas incidência acumulada, taxa de mortalidade, letalidade e proporção de testes positivos. Os dados foram descritos e apresentados graficamente, com o respectivo coeficiente de correlação de Spearman. Resultados: A taxa de testagem variou enormemente entre os países. A incidência acumulada e a proporção de testes positivos foram correlacionadas ao número de testes, enquanto a taxa de mortalidade e a letalidade apresentaram correlação baixa com esse indicador. Conclusão: A maioria dos países não testa o suficiente para garantir adequado monitoramento da pandemia, com reflexo na qualidade dos indicadores. A ampliação do número de testes é fundamental; porém, ela deve ser acompanhada de outras medidas, como isolamento de casos diagnosticados e rastreamento de contatos.


Objetivo: Analizar cómo el testeo poblacional influye en los indicadores de salud utilizados para monitorear la pandemia de COVID-19 en los 50 países con mayor número de casos diagnosticados. Métodos: Estudio ecológico, con datos secundarios, recogidos el 19/8/2020. Se calcularon la incidencia acumulada, la tasa de mortalidad, la letalidad y la proporción de pruebas positivas. Los datos fueron descritos y presentados gráficamente, con el respectivo Coeficiente de Correlación de Spearman. Resultados: La tasa de testeo varió enormemente entre los países. La incidencia acumulada y la proporción de pruebas positivas se correlacionaron con el número de pruebas, mientras que la tasa de mortalidad y de letalidad mostraron una baja correlación con este indicador. Conclusión: La mayoría de los países no realizan suficientes pruebas para garantizar un seguimiento adecuado de la pandemia, lo que se refleja en la calidad de los indicadores. La ampliación del número de pruebas es fundamental, y debe ir acompañada de aislamiento de casos y seguimiento de contactos.


Objective: To analyse how testing the population influences the health indicators used to monitor the COVID-19 pandemic in the 50 countries with the highest number of diagnosed cases. Methods:This was an ecological study using secondary data retrieved on 8/19/2020. Cumulative incidence, mortality rate, case-fatality rate, and proportion of positive tests were calculated. The data were described and presented graphically, with their respective Spearman Correlation Coefficients. Results: The testing rate varied enormously between countries. Cumulative incidence and the proportion of positive tests were correlated with the number of tests, while the mortality rate and case-fatality rate showed low correlation with this indicator. Conclusion: Most countries do not test enough to ensure adequate monitoring of the pandemic, and this is reflected in the quality of the indicators. Expanding the number of tests is essential, but it needs to be accompanied by other measures, such as isolation of diagnosed cases and contact tracing.


Subject(s)
Humans , Incidence , Coronavirus Infections/diagnosis , Coronavirus Infections/mortality , Coronavirus Infections/epidemiology , Laboratory Test/statistics & numerical data , Serologic Tests/statistics & numerical data , Global Health/statistics & numerical data , Health Status Indicators , Reverse Transcriptase Polymerase Chain Reaction , Pandemics/statistics & numerical data
5.
J. afr. imag. méd ; 13(1): 1-11, 2021. Tables, figures
Article in French | AIM | ID: biblio-1342827

ABSTRACT

Objectifs :Évaluer l'apport de la TDM thoracique dans le diagnostic des patients suspects de COVID-19en comparaison avec la technique de référence (RT-PCR) et déterminer l'impact médico-économique de la COVID-19 au service de radiologie du CHU de Fann. Matériels et méthodes: Il s'agissait d'une étude rétrospective, descriptive sur une période de 4 mois allant du 1er avril au 31 Juillet 2020, au service de radiologie du CHU de Fann.Ont été inclus les patients reçus pour suspicion clinique de COVID-19, qui avaient eu une TDM thoracique et un prélèvement naso-pharyngé par écouvillonnage pour RT-PCR, soit au total 314 patients. Nous avons étudié les données épidémiologiques, cliniques, les images évocatrices de COVID-19 (opacités en verre dépoli, condensation, topographie lésionnelle), existence ou non d'une embolie, les anomalies en faveur de surinfection, les lésions associées, l'impact sur la fréquentation des différentes modalités etl'impact sur les recettes. Résultats:L'âge médian était de 62 ans et le sex-ratio 1,61. La fièvre a été présente chez 7 patients (2,23%); la toux chez 17 patients (5,41%); la dyspnée chez 30 patients (9,55%) et un syndrome de détresse respiratoire chez 63 patients (20,07%). La clinique n'a pas été précisée chez 163 patients (51,91%). La TDM thoracique était normale chez 20 patients (6,37%), évocatrice de COVID-19 chez 274 patients (87,26%) et non évocatrice de COVID-19 chez 20 patients (6,37%). La RT-PCR était positive chez 125 patients soit 39,80%. La sensibilité et la spécificité de la TDM étaient respectivement de 91,2% et 15,34%. La valeur prédictive positive, la valeur prédictive négative et le taux de précision étaient respectivement de 42%, 72,5% et 45,5%. La baisse du taux de fréquentation était de 59% en radiographie standard, 55% en échographie, 24% au scanner et 87% en mammographie. Dans notre étude on a noté une baisse de 40% des recettes au second trimestre de 2020 comparativement au premier trimestre. Conclusion: La TDM thoracique a une bonne sensibilité pour le diagnostic de la COVID-19. De ce fait, elle peut être considérée comme un outil principal pour la détection des lésions pulmonaires évocatrices de pneumonie COVID-19. Les impacts médico-économiques de la COVID-19 ont été considérables.


Subject(s)
Humans , Male , Female , Mass Chest X-Ray , Reverse Transcriptase Polymerase Chain Reaction , COVID-19 , Senegal , Economics
6.
Article in English | WPRIM | ID: wpr-880352

ABSTRACT

BACKGROUND@#Arsenic is a developmental neurotoxicant. It means that its neurotoxic effect could occur in offspring by maternal arsenic exposure. Our previous study showed that developmental arsenic exposure impaired social behavior and serotonergic system in C3H adult male mice. These effects might affect the next generation with no direct exposure to arsenic. This study aimed to detect the social behavior and related gene expression changes in F2 male mice born to gestationally arsenite-exposed F1 mice.@*METHODS@#Pregnant C3H/HeN mice (F0) were given free access to tap water (control mice) or tap water containing 85 ppm sodium arsenite from days 8 to 18 of gestation. Arsenite was not given to F1 or F2 mice. The F2 mice were generated by mating among control F1 males and females, and arsenite-F1 males and females at the age of 10 weeks. At 41 weeks and 74 weeks of age respectively, F2 males were used for the assessment of social behavior by a three-chamber social behavior apparatus. Histological features of the prefrontal cortex were studied by ordinary light microscope. Social behavior-related gene expressions were determined in the prefrontal cortex by real time RT-PCR method.@*RESULTS@#The arsenite-F2 male mice showed significantly poor sociability and social novelty preference in both 41-week-old group and 74-week-old group. There was no significant histological difference between the control mice and the arsenite-F2 mice. Regarding gene expression, serotonin receptor 5B (5-HT 5B) mRNA expression was significantly decreased (p < 0.05) in the arsenite-F2 male mice compared to the control F2 male mice in both groups. Brain-derived neurotrophic factor (BDNF) and dopamine receptor D1a (Drd1a) gene expressions were significantly decreased (p < 0.05) only in the arsenite-F2 male mice of the 74-week-old group. Heme oxygenase-1 (HO-1) gene expression was significantly increased (p < 0.001) in the arsenite-F2 male mice of both groups, but plasma 8-hydroxy-2'-deoxyguanosine (8-OHdG) and cyclooxygenase-2 (COX-2) gene expression were not significantly different. Interleukin-1β (IL-1β) mRNA expression was significantly increased only in 41-week-old arsenite-F2 mice.@*CONCLUSIONS@#These findings suggest that maternal arsenic exposure affects social behavior in F2 male mice via serotonergic system in the prefrontal cortex. In this study, COX-2 were not increased although oxidative stress marker (HO-1) was increased significantly in arsnite-F2 male mice.


Subject(s)
Animals , Arsenic/toxicity , Arsenites/toxicity , Behavior, Animal/drug effects , Environmental Pollutants/toxicity , Female , Gene Expression/drug effects , Genetic Markers , Male , Maternal Exposure/adverse effects , Mice , Mice, Inbred C3H , Oxidative Stress/genetics , Prefrontal Cortex/drug effects , Pregnancy , Prenatal Exposure Delayed Effects/psychology , Reverse Transcriptase Polymerase Chain Reaction , Serotonin/metabolism , Social Behavior , Sodium Compounds/toxicity
7.
Acta Medica Philippina ; : 211-215, 2021.
Article in English | WPRIM | ID: wpr-876875

ABSTRACT

@#Objective. To determine the diagnostic accuracy of self-collected snorted and spit saliva in detecting COVID-19 using RT-PCR (ssRT-PCR) and lateral flow antigen test (ssLFA) versus nasopharyngeal swab RT-PCR (npRT-PCR). Methods. One hundred ninety-seven symptomatic subjects for COVID-19 testing in a tertiary hospital underwent snort-spit saliva self-collection for RT-PCR and antigen testing and nasopharyngeal swab for RT-PCR as reference. Positivity rates, agreement, sensitivity, specificity, and likelihood ratios were estimated. Results. Estimated prevalence of COVID-19 using npRT-PCR was 9% (exact 95% CI of 5.5% - 14.1%). A higher positivity rate of 13% in the ssRT-PCR assay suggested possible higher viral RNA in the snort-spit samples. There was 92.9% agreement between ssRT-PCR and npRT-PCR (exact 95% CI of 88.4% to 96.1%; Cohen’s Kappa of 0.6435). If npRT-PCR will be assumed as reference standard, the estimated Sensitivity was 83.3% (exact 95% CI of 60.8% to 94.2%), Specificity 93.9% (exact 95% CI of 89.3% to 96.5%), Positive predictive value of 57.7% (exact 95% CI of 38.9% to 74.5%), Negative predictive value of 98.2% (exact 95% CI of 95% to 99.4%), positive likelihood ratio of 3.65 (95% CI of 7.37 to 24.9), negative likelihood ratio of 0.178 (95% CI of 0.063 to 0.499). There was 84.84% agreement (95% exact CI of 79.1% to 89.5%; Cohen’s Kappa of 0.2356) between ssLFAvs npRT-PCR, sensitivity of 38.9% (exact 95% CI of 20.3% to 61.4%), specificity of 89.4% (exact 95% CI of 84.1% to 93.1%), PPV of 26.9% (95% CI of 13.7% to 46.1%), NPV of 93.6% (exact 95% CI of 88.8% to 96.4%), LR+ of 3.67 (95% CI of 1.79 - 7.51), LR – of 0.68 (95% CI of 0.47 - 0.99). Conclusion. Our data showed that snort-spit saliva RT-PCR testing had acceptable diagnostic performance characteristics and can potentially be used as an alternative to the standard nasopharyngeal/oropharyngeal swab RT-PCR test for COVID-19 in certain situations. However, our data also showed that snort-spit saliva antigen testing using lateral flow assay did not offer acceptable performance.


Subject(s)
Saliva , SARS-CoV-2 , Reverse Transcription , Reverse Transcriptase Polymerase Chain Reaction
8.
Mem. Inst. Oswaldo Cruz ; 116: e200443, 2021. tab, graf
Article in English | LILACS | ID: biblio-1154874

ABSTRACT

BACKGROUND The coronaviruses (CoVs) called the attention of the world for causing outbreaks of severe acute respiratory syndrome (SARS-CoV), in Asia in 2002-03, and respiratory disease in the Middle East (MERS-CoV), in 2012. In December 2019, yet again a new coronavirus (SARS-CoV-2) first identified in Wuhan, China, was associated with a severe respiratory infection, known today as COVID-19. This new virus quickly spread throughout China and 30 additional countries. As result, the World Health Organization (WHO) elevated the status of the COVID-19 outbreak from emergency of international concern to pandemic on March 11, 2020. The impact of COVID-19 on public health and economy fueled a worldwide race to approve therapeutic and prophylactic agents, but so far, there are no specific antiviral drugs or vaccines available. In current scenario, the development of in vitro systems for viral mass production and for testing antiviral and vaccine candidates proves to be an urgent matter. OBJECTIVE The objective of this paper is study the biology of SARS-CoV-2 in Vero-E6 cells at the ultrastructural level. METHODS In this study, we documented, by transmission electron microscopy and real-time reverse transcription polymerase chain reaction (RT-PCR), the infection of Vero-E6 cells with SARS-CoV-2 samples isolated from Brazilian patients. FINDINGS The infected cells presented cytopathic effects and SARS-CoV-2 particles were observed attached to the cell surface and inside cytoplasmic vesicles. The entry of the virus into cells occurred through the endocytic pathway or by fusion of the viral envelope with the cell membrane. Assembled nucleocapsids were verified inside rough endoplasmic reticulum cisterns (RER). Viral maturation seemed to occur by budding of viral particles from the RER into smooth membrane vesicles. MAIN CONCLUSIONS Therefore, the susceptibility of Vero-E6 cells to SARS-CoV-2 infection and the viral pathway inside the cells were demonstrated by ultrastructural analysis.


Subject(s)
Humans , Animals , Vero Cells/virology , Cytoplasmic Vesicles/virology , Cytopathogenic Effect, Viral , SARS-CoV-2/physiology , Chlorocebus aethiops , Nucleocapsid , Reverse Transcriptase Polymerase Chain Reaction , Microscopy, Electron, Transmission , Endocytosis , Endoplasmic Reticulum/virology , Virus Internalization , Real-Time Polymerase Chain Reaction
9.
Mem. Inst. Oswaldo Cruz ; 116: e200571, 2021. tab, graf
Article in English | LILACS | ID: biblio-1154878

ABSTRACT

Leishmania infantum chagasi is the causative agent and Lutzomyia longipalpis is the main vector of visceral leishmaniasis in the Americas. We investigated the expression of Leishmania genes within L. longipalpis after artificial infection. mRNAs from genes involved in sugar and amino acid metabolism were upregulated at times of high parasite proliferation inside the insect. mRNAs from genes involved in metacyclogenesis had higher expression in late stages of infection. Other modulated genes of interest were involved in immunomodulation, purine salvage pathway and protein recycling. These data reveal aspects of the adaptation of the parasite to the microenvironment of the vector gut and reflect the preparation for infection in the vertebrate.


Subject(s)
Animals , Psychodidae/parasitology , Leishmania infantum/genetics , Insect Vectors/parasitology , Leishmania/isolation & purification , Leishmaniasis, Visceral/transmission , Psychodidae/genetics , Brazil , Gene Expression , Reverse Transcriptase Polymerase Chain Reaction/methods , Leishmaniasis, Visceral/parasitology , Leishmaniasis, Visceral/epidemiology , Life Cycle Stages
10.
Rev. Soc. Bras. Med. Trop ; 54: e07792020, 2021. tab, graf
Article in English | LILACS | ID: biblio-1155583

ABSTRACT

Abstract INTRODUCTION Rio de Janeiro has hardly experienced coronavirus disease. METHODS Here, 87,442 reverse transcription polymerase chain reaction (RT-PCR) test results for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were reported among Rio de Janeiro residents (March to September 2020). RESULTS Overall, RT-PCR positivity of 44.6% decreased over time towards 20%. Positivity was greater among males (OR=1.22; 95%CI:1.19-1.26); Black (OR=1.10; 95%CI:1.02-1.19), Brown (OR=1.16; 95%CI:1.10-1.22), and indigenous people (OR=2.11; 95%CI:0.88-5.03) compared to Whites and increased with age; with epidemic spread from the capital to inland regions. CONCLUSIONS SARS-CoV-2 keeps spreading in Rio de Janeiro, and reopening of activities may fuel the epidemic.


Subject(s)
Humans , Male , Coronavirus Infections , Betacoronavirus , Brazil/epidemiology , Incidence , Reverse Transcriptase Polymerase Chain Reaction
12.
Int. j. odontostomatol. (Print) ; 14(4): 540-543, dic. 2020.
Article in Spanish | LILACS | ID: biblio-1134534

ABSTRACT

RESUMEN: El coronavirus tipo 2, SARS-CoV-2, que causa la enfermedad denominada por la OMS como COVID-19, se ha expandido provocando una pandemia desde 2019, sin cura hasta la fecha. El mecanismo de transmisión del SARS-CoV-2 entre humanos es mediante las secreciones generadas durante la respiración y estornudos, presentándose con un período de incubación desde 1 a 14 días. Se describen fiebre, tos y astenia como los síntomas más habituales. El diagnóstico definitivo se logra a través de la correlación entre la presentación clínica y exámenes complementarios, pero en la actualidad, el método de muestreo de preferencia para el diagnóstico de SARS-CoV-2 es mediante una muestra de nasofaringe, en donde se analiza la presencia de material genético viral por medio de RT-PCR. Debido a las complicaciones en la obtención de la muestra, tanto para el personal sanitario como para el paciente, se ha implementado la muestra de saliva con finalidad diagnóstica, como un método que proporciona una detección rápida, simple y no invasiva de la infección viral. Esta alternativa diagnóstica podría entregar información respecto a la patogenia de la enfermedad, permitiendo el manejo y control de pacientes positivos. El siguiente artículo, tiene por objetivo realizar una comparación entre las tomas de muestra de saliva y de nasofaringe para el diagnóstico de SARS-CoV-2, mediante la prueba de reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR).


SUMMARY: The type 2 coronavirus, SARS-CoV-2, named by the WHO like COVID-19, has expanded causing a pandemic since 2019, with no cure to date. The mechanism of transmission of SARS-CoV-2 between humans is through secretions generated during breathing and sneezing, presenting with an incubation period range from 1 - 14 days. Fever, cough, and fatigue are described as the most common symptoms. The definitive diagnosis is achieved through the correlation between the clinical presentation and the complementary exams, but at present, the preferred sampling method for the diagnosis of SARS-CoV-2 is through a nasopharyngeal swab specimen, where it is analyzed the presence of viral genetic material by the RT-PCR. Due to the complications in obtaining the sample, both for health personnel and for the patient, the saliva sample has been implemented, as a method that provides rapid, simple and non-invasive detection of viral infection. This diagnostic alternative could provide information on the pathogenesis of the disease, the management and control of positive patients. The following article aims to make a comparison between the saliva and nasopharyngeal samples taken for the diagnosis of SARS-CoV-2, using the reverse transcription polymerase chain reaction test (RT-PCR).


Subject(s)
Saliva/virology , Coronavirus Infections/diagnosis , Reverse Transcriptase Polymerase Chain Reaction/methods , Betacoronavirus , Nasopharynx/virology , Coronavirus Infections/epidemiology , Clinical Laboratory Techniques
13.
Medwave ; 20(10)30-11-2020.
Article in English, Spanish | LILACS | ID: biblio-1145814

ABSTRACT

Introducción Los resultados del confinamiento obligatorio han sido perjudiciales en varios aspectos. No obstante, han surtido efecto en lograr el descenso de casos activos de COVID-19. Chile ha comenzado la desescalada y precisa conocer el mejor momento para poner fin a las restricciones. Objetivos Discutir las mejores condiciones y garantías para el fin del confinamiento obligatorio sobre la base de los casos nuevos, casos activos y positividad de exámenes de reacción en cadena de la polimerasa. Métodos Estudio basado en un modelo de tendencia con estimación de predicciones. Los datos de las variables de interés fueron sometidas a estudios de regresión lineal, con el objeto de determinar la curva que mejor explicaba los datos. Se estimó el coeficiente de determinación, la desviación estándar de y en x y el intervalo de confianza de la curva observada. Posteriormente, fue escogida la curva de tendencia en concordancia con las estimaciones de regresión. Resultados Se encontró que todas las variables dependientes tendían a disminuir con el tiempo de forma cuadrática, con excepción de la variable casos nuevos. En general, las estimaciones de coeficiente de determinación (R2) y error porcentual absoluto medio son satisfactorias, con excepción de la variable: número de exámenes de reacción en cadena de la polimerasa por día. Conclusiones Se deben tomar medidas graduales y cautelosas antes de poner fin al confinamiento obligatorio. En la actual desescalada, se deben aumentar los exámenes de reacción en cadena de la polimerasa diarios y mantener vigilancia en los indicadores de incidencia, prevalencia y positividad de dichos exámenes. La evidencia sugiere con cierto grado de confiabilidad que el confinamiento obligatorio podría levantarse de forma segura a contar del día 30 de agosto de 2020. Se deben hacer preparativos a largo plazo en contención de las futuras olas, es decir, una nueva alza de casos nuevos y activos luego del descenso.


Introduction The results of mandatory confinement have been detrimental in several respects. Nonetheless, they have resulted in reducing the number of active cases of COVID-19. Chile has begun the de-escalation and needs to know the best time to end the restrictions. Objective We discuss the best conditions and guarantees for the end of compulsory confinement. Methods This study is based on a trend model with prediction estimation. The data of the variables of interest were subjected to linear regression studies to determine the curve that best explained the data. The coefficient of determination, the standard deviation of y in x, and the confidence interval of the observed curve were estimated. The trend curve was chosen in accordance with the regression estimates. Outcomes It was found that all dependent variables tended to decrease over time in a quadratic fashion, except for the new cases variable. In general, the R2 and MAPE estimates are satisfactory, except for the variable number of PCR tests per day. Conclusions Gradual and cautious steps should be taken before ending mandatory confinement. In the current de-escalator, daily PCR tests should be increased, maintaining vigilance on indicators of incidence, prevalence, and positivity of PCR tests. Evidence suggests with some degree of confidence that mandatory confinement could be safely lifted as of August 30, 2020. Long-term preparations must be made to contain future waves of new cases.


Subject(s)
Pneumonia, Viral/prevention & control , Pneumonia, Viral/epidemiology , Quarantine/standards , Coronavirus Infections/prevention & control , Coronavirus Infections/epidemiology , Reverse Transcriptase Polymerase Chain Reaction/statistics & numerical data , Pandemics , Betacoronavirus , Confidence Intervals , Linear Models , Chile/epidemiology , Incidence , Prevalence , Reverse Transcriptase Polymerase Chain Reaction/trends
14.
Electron. j. biotechnol ; 48: 78-85, nov. 2020. ilus, tab
Article in English | LILACS | ID: biblio-1254957

ABSTRACT

BACKGROUND: Coconut tissues consist of a complex network of polysaccharides, proteins, polyphenols, and lipids that can bind to nucleic acids and pose difficulty in isolation. Certainly, a vigorous method is required to isolate high quality and quantity of RNA from such tissues for the purpose of downstream experiments. In this paper, we discuss a newly developed method for the Isolation of RNA from Complex Matrices (IRCM) method from coconut tissues. RESULTS: The method is robust, cheap, and efficient for the extraction of quality RNA in high quantities from the solid endosperm of stored and fresh coconut (150 µg/g FW with A260/280 = 1.89 and 247.5 µg/g FW with A260/280 = 1.91), coconut apple (263.8 µg/g FW with A260/280 = 1.97), and coconut bud (1052.5 µg/g FW with A260/280 = 2.00). The other well established methods, such as Method of RNA Isolation from Palm (MRIP), Cetyl Trimethyl Ammonium Bromide (CTAB), TRIZOL, and RNA plant kit failed to isolate quality RNA in appreciable quantities from the coconut tissues. Furthermore, the resultant RNA performed well in the downstream experiment, that is, RT-PCR for the production and amplification of cDNA. CONCLUSIONS: From the study, we concluded that the present method will play a vital role in the extraction of high quality RNA from complex matrices in a short time.


Subject(s)
RNA/isolation & purification , Cocos/genetics , Reverse Transcriptase Polymerase Chain Reaction
15.
Säo Paulo med. j ; 138(5): 422-432, Sept.-Oct. 2020. tab, graf
Article in English | LILACS, SES-SP | ID: biblio-1139724

ABSTRACT

ABSTRACT BACKGROUND: A positive real-time reverse-transcriptase polymerase chain reaction (RT-PCR) for SARS CoV-2, from nasopharyngeal swabs, is the current gold standard diagnostic test for this virus and has sensitivity of 60-70%. Some studies have demonstrated a significant number of false-negative RT-PCR tests while displaying significant tomographic findings, in the early days of symptoms of COVID-19. OBJECTIVE: To compare accuracy between RT-PCR and computed tomography (CT) for detecting COVID-19 in the first week of its symptoms during the pandemic. DESIGN AND SETTING: Systematic review of comparative studies of diagnostic accuracy within the Evidence-based Health Program of a federal university in São Paulo (SP), Brazil. METHODS: A systematic search of the relevant literature was conducted in the PubMed, EMBASE, Cochrane Library, CINAHL and LILACS databases, for articles published up to June 6, 2020, relating to studies evaluating the diagnostic accuracy of RT-PCR and chest CT for COVID-19 diagnoses. The QUADAS 2 tool was used for methodological quality evaluation. RESULTS: In total, 1204 patients with COVID-19 were evaluated; 1045 had tomographic findings while 755 showed positive RT-PCR for COVID-19. RT-PCR demonstrated 81.4% sensitivity, 100% specificity and 92.3% accuracy. Chest CT demonstrated 95.3% sensitivity, 43.8% specificity and 63.3% accuracy. CONCLUSION: The high sensitivity and detection rates shown by CT demonstrate that this technique has a high degree of importance in the early stages of the disease. During an outbreak, the higher prevalence of the condition increases the positive predictive value of CT. REGISTRATION NUMBER: DOI: 10.17605/OSF.IO/UNGHA in the Open Science Framework.


Subject(s)
Humans , Pneumonia, Viral/diagnosis , Tomography, X-Ray Computed , Coronavirus Infections/diagnosis , Reverse Transcriptase Polymerase Chain Reaction , Brazil , Sensitivity and Specificity , Clinical Laboratory Techniques/methods , Pandemics , Betacoronavirus , COVID-19 Vaccines , COVID-19 Testing , SARS-CoV-2 , COVID-19
16.
J. coloproctol. (Rio J., Impr.) ; 40(3): 253-260, July-Sept. 2020. tab, graf
Article in English | LILACS | ID: biblio-1134986

ABSTRACT

Abstract Ulcerative colitis is one of the IBDs. Its etiology and pathogenesis remain undefined with an interaction between environmental, genetic and immunological factors is the most accepted explanation. Several recent studies have examined microRNA expression in the peripheral blood and tissues from IBD patients. The study aims at assessing the expression of serum miR-16 in ulcerative colitis patients and its correlation with disease extent, activity and severity. It included 30 treatment naïve ulcerative colitis patients of different presentations. Serum miR-16 expression was assessed using reverse transcriptase quantitative real time PCR (RT-qPCR), and then correlated with that of a group of 20 healthy subjects to assess its role in diagnosis of ulcerative colitis. Also, it was correlated with disease extent (proctitis, left sided colitis, extensive colitis) and disease activity and severity indices (Truelove and Witts criteria, fecal calprotectin and UCEIS). Thirty ulcerative colitis patients were enrolled, 53% had mild, 37% had moderate, while 10% had severe disease. Concerning endoscopic extent, 8 had proctitis, 14 had left sided colitis and 8 had extensive colitis. Serum expression of miR-16 in the 30 patients were compared to that of the healthy control subjects. The patients' group showed median serum miR-16 expression of 1.91, 1.13 for the control group with a significant difference between both groups. Correlation between serum miR-16 expression with disease extent, activity and severity showed no significant relation. From the current study we can conclude that increased serum expression of miR-16 is associated with ulcerative colitis despite no significant relation to disease activity extent or severity.


Resumo A colite ulcerativa é uma das DII. Sua etiologia e patogênese permanecem indefinidas; a interação entre fatores ambientais, genéticos e imunológicos é a explicação mais aceita. Vários estudos recentes avaliaram a expressão de microRNA no sangue e tecidos periféricos em pacientes com DII. O presente estudo teve como objetivo avaliar a expressão do miR-16 sérico em pacientes com colite ulcerativa e sua correlação com a extensão, atividade e gravidade da doença. Foram incluídos 30 pacientes de colite ulcerativa, com diferentes apresentações, que ainda não haviam sido submetidos a nenhum tipo de tratamento. A expressão sérica de miR-16 foi avaliada usando transcrição reversa seguida de reação em cadeia da polimerase quantitativa (RT-qPCR) e, em seguida, correlacionada com a de um grupo de 20 indivíduos saudáveis para avaliar seu papel no diagnóstico de colite ulcerativa. Além disso, foi feita uma correlação com a extensão da doença (proctite, colite do lado esquerdo, colite extensa) e com os índices de atividade e gravidade da doença (critérios de Truelove e Witts, calprotectina fecal e UCEIS). Trinta pacientes com colite ulcerativa foram incluídos no estudo, classificada como leve em 53%, moderada em 37% e grave em 10%. Quanto à extensão endoscópica, oito apresentavam proctite, 14 apresentavam colite do lado esquerdo e oito apresentavam colite extensa. A expressão sérica de miR-16 nos 30 pacientes foi comparada à dos indivíduos controle saudáveis. No, grupo de pacientes, a expressão sérica de miR-16 foi de 1,91 (grupo controle: 1,13), uma diferença estatisticamente significativa entre os dois grupos. Não foi observada relação significativa entre a expressão sérica de miR-16 e a extensão, atividade e gravidade da doença. A partir do presente estudo, pode-se concluir que o aumento da expressão sérica do miR-16 está associado à colite ulcerativa, apesar de não haver relação significativa com a extensão ou gravidade da atividade da doença.


Subject(s)
Humans , Male , Female , Colitis, Ulcerative/genetics , Colitis, Ulcerative/pathology , MicroRNAs , Inflammatory Bowel Diseases , Reverse Transcriptase Polymerase Chain Reaction , Reverse Transcription , Real-Time Polymerase Chain Reaction
17.
Buenos Aires; IECS; 4 sept. 2020.
Non-conventional in Spanish | LILACS, BRISA | ID: biblio-1140941

ABSTRACT

CONTEXTO CLÍNICO: La enfermedad por el Coronavirus 2019 (COVID­19, por su sigla en inglés Coronavirus Disease 2019) es una enfermedad respiratoria de humanos producida por un nuevo coronavirus identificado con la sigla SARS-CoV-2. El 11 de marzo de 2020 la Organización Mundial de la Salud (OMS) declaro la COVID-19 como uma pandemia. Desde ese momento hasta el 30 agosto 2020 su circulación se ha reportado en más de 200 países reportándose más de 25.000.000 casos activos. La tasa de letalidad del COVID-19 a la fecha, sobre los casos cerrados es del 9% (846.000 muertes). El período de incubación de la infección por 2019­nCoV es de 2 a 14 días. La mayor parte de los contagios se producen persona a persona, siendo altamente transmisible. La clínica varía desde casos asintomáticos a cuadros febriles con tos y dificultad respiratoria, neumonía y distrés respiratorio. Debido a la falta de tratamiento o vacunas para la epidemia por COVID-19 se han establecido distintas medidas para evitar la propagación del virus y el auto cuidado de la gente como el distanciamento social, el lavado de manos o el uso de tapa bocas a nivel social. TECNOLOGÍA: La prueba Polimerasa Transcriptasa Inversa (RT- PCR) utiliza una enzima llamada RT que es capaz de convertir el ARN en ADN por retro transcripción dado que el virus SARS-CoV-2 no tiene ADN en su interior sino ARN. Se realiza en laboratorios con equipos especializados en tres tipos de muestras: el esputo, que es una secreción procedente de la nariz, la garganta o los bronquios; de un lavado bronco alveolar o aspirado traqueal (cuando sea posible) y/o hisopado de garganta o nariz. El sistema de PCR a tiempo real permite cuantificar la muestra, es decir, saber cuántas copias del virus hay por mililitro. OBJETIVO: El objetivo del presente informe es evaluar la evidencia disponible acerca de la utilidad de la evaluación diagnóstica preoperatoria para COVID-19. MÉTODOS: Se realizó una búsqueda en las principales bases de datos bibliográficas, en buscadores genéricos de internet, y financiadores de salud. Se priorizó la inclusión de revisiones sistemáticas (RS), ensayos clínicos controlados aleatorizados (ECAs), evaluaciones de tecnologías sanitarias (ETS), evaluaciones económicas y guías de práctica clínica (GPC) y recomendaciones de diferentes sistemas de salud. RESULTADOS: Se incluyeron una ETS y 14 GPC o recomendaciones, acerca del uso del cribado preoperatorio del SARS­CoV­ 2. CONCLUSIONES: No se encontró evidencia de la eficacia ni la seguridad de la implementación de la evaluación diagnostica preoperatoria para la detección del SARS-CoV-2 / COVID-19. Las recomendaciones sobre la evaluación prequirúrgica con PCR en tiempo real para pacientes asintomáticos son heterogéneas y dependen de los niveles de casos a nivel nacional, políticas en cada institución para la creación de protocolos específicos para la evaluación de pacientes quirúrgicos consensuados com las normativas sobre COVID-19. La Sociedad de Argentina de Cirugía sugiere que ante la necesidad de una cirugía urgente testear a todos los pacientes que cumplan los criterios de caso sospechosos o contacto estrecho de COVID-19. En el caso de que un paciente con diagnóstico de COVID-19 requiera de una cirugía de urgencia, usar los protocolos de cada institución sobre sobre el manejo de casos COVID-19 en área quirúrgica médica y si es posible, se recomienda disponer de un quirófano específico sólo para pacientes COVID-19 positivos. También recomiendan que ante una curva en aumento de casos positivos suspender toda consulta y cirugía programada. Las asociaciones de cirugía de España, Australia, las asociaciones de cirujanos, anestesistas y financiadores privados de salud estadounidenses recomiendan el testeo prequirúrgico para COVID-19 en todo paciente que requiera cirugía electiva. En el caso de cirugías de urgencia evaluar la posibilidad de reprogramar la cirugía hasta tener el resultado del hisopado para COVID-19.


Subject(s)
Humans , Coronavirus Infections/diagnosis , Reverse Transcriptase Polymerase Chain Reaction/methods , Technology Assessment, Biomedical , Cost-Benefit Analysis
18.
Rev. argent. salud publica ; 12(Suplemento Covid-19): 1-7, 23 de Julio 2020.
Article in Spanish | LILACS, BINACIS, ARGMSAL | ID: biblio-1145389

ABSTRACT

El manejo de las infecciones virales respiratorias, tanto a nivel nacional como a nivel mundial, requiere resultados científicos de calidad. La reacción en cadena de la polimerasa de transcriptasa inversa (rRT-PCR, por su sigla en inglés) es considerada el "patrón de oro" para detectar el genoma del nuevo coronavirus 2 (SARS-CoV-2), agente causal de la enfermedad por el nuevo coronavirus (COVID-19) sobre todo en la fase aguda de la infección. Su uso es controvertido fuera de un contexto de exposición viral. El objetivo del presente trabajo es analizar escollos encontrados durante la detección del genoma del SARS-CoV-2 que pueden producir resultados falsos. Los falsos negativos de rRT-PCR pueden deberse al momento y la eficacia de la toma de la muestra, la congelación, el almacenamiento y la descongelación, y a la inactivación térmica de la virulencia. Además, las señales retardadas de los controles internos invalidan la negatividad. Por otra parte, las muestras con escaso material biológico llevan a conclusiones negativas falsas, por lo que determinar un umbral (número mínimo de células epiteliales) contribuirá a reducirlas. Sin embargo, la mayoría de los kits detectan ADN humano, pero no fueron calibrados para cuantificar carga celular. Los ácidos ribonucleicos nucleares (ARN) virales adheridos a guantes, tubos y gorros, -entre otros elementos-, son fuente de falsos positivos. Las farmacopeas sugieren que la contaminación externa se controle en series de 100 muestras con al menos una representatividad del 10%. Si se extrapola esta aproximación al laboratorio de análisis clínicos, en lugar de uno se deberían procesar al menos 10 controles negativos contiguos a 10 positivos cada 100 pruebas. Mejorar la detección por rRT-PCR implica un aumento de al menos 20% en el costo de los reactivos, por lo que se necesitan recursos adicionales.


Subject(s)
Coronavirus Infections , Reverse Transcriptase Polymerase Chain Reaction , False Negative Reactions , False Positive Reactions
19.
Brasília; s.n; maio 2020.
Non-conventional in Portuguese | LILACS, BRISA | ID: biblio-1099659

ABSTRACT

INTRODUÇÃO: O coronavírus da Síndrome Respiratória Aguda Grave 2 (abreviado para SARSCoV-2, do inglês Severe Acute Respiratory Syndrome Coronavirus 2), anteriormente conhecido como novo coronavírus (2019-nCoV), é um agente zoonótico recémemergente que surgiu em dezembro de 2019, em Wuhan, China, causando manifestações respiratórias, digestivas e sistêmicas, que se articulam no quadro clínico da doença denominada COVID-19 (do inglês Coronavirus Disease 2019). Ainda não há informações robustas sobre a história natural da doença, tampouco sobre as medidas de efetividade para o manejo clínico dos casos de infecção pelo COVID19, restando ainda muitos detalhes a serem esclarecidos. No entanto, sabe-se que o vírus tem alta transmissibilidade e provoca uma síndrome respiratória aguda que varia de casos leves ­ cerca de 80% ­ a casos muito graves com insuficiência respiratória - entre 5% e 10% dos casos ­, os quais requerem tratamento especializado em unidades de terapia intensiva (UTI). Sua letalidade varia, principalmente, conforme a faixa etária. TECNOLOGIA: Os testes de diagnóstico para a COVID-19 se destacaram na pandemia de coronavírus em andamento como uma ferramenta essencial para rastrear a propagação da doença. Uma ampla gama de testes diagnósticos para o SARS-CoV-2 está disponível comercialmente, alguns dos quais receberam autorizações para uso por várias agências reguladoras nacionais. Com as informações da sequência genética devidamente identificadas, os testes de diagnóstico baseados na detecção da sequência viral por reação em cadeia da polimerase com transcriptase reversa (RT-PCR) ou plataformas de sequenciamento logo se tornaram disponíveis. Isso permitiu a confirmação do diagnóstico e melhores estimativas da atividade da infecção, que vêm aumentando em velocidades alarmantes. Para a detecção mais sensível de SARS-CoV, MERS-CoV e SARS-CoV-2, recomendavam-se a coleta e o teste de amostras respiratórias superiores e inferiores. O diagnóstico de casos suspeitos era confirmado por testes de RNA com RT-PCR em tempo real ou sequenciamento de próxima geração. Foi demonstrado que o RNA viral poderia ser detectado a partir do swab nasal e faríngeo, lavagem broncoalveolar e plasma sanguíneo usando RT-PCR direcionado ao gene do vírus (5). O padrão-ouro para diagnóstico laboratorial da COVID-19 é a reação da transcriptase reversa, seguida de reação em cadeia da polimerase (RT-PCR) para amostras coletadas no trato respiratório superior ou inferior. OBJETIVO: O objetivo deste relatório é analisar a acurácia dos testes diagnósticos registrados na Agência Nacional de Vigilância Sanitária (ANVISA) até a presente data. METODOLOGIA: foi realizada uma busca por diagnósticos para COVID-19 com registros vigentes na ANVISA. Para tal, foram utilizados os termos "COVID 19", SARS e coronavírus no campo de consulta de registro de produtos para saúde no site da Agência (https://consultas.anvisa.gov.br/#/saude/). Os passos para acesso ao banco de dados de produtos diagnósticos na ANVISA são: 1) consulta produtos; 2) consulta a banco de dados; 3) produtos para a saúde e 4) pesquisa de produtos para a saúde registrados. CONCLUSÕES: A ANVISA já avaliou mais de 120 pedidos de registro de produtos para testagens relacionadas à COVID-19 desde o dia 18 de março. A maior parte das petições aguarda complementação de informações por parte das empresas e outras estão sendo analisadas com prioridade. O tempo médio para avaliação dos registros na ANVISA gira em torno de 15 dias. Atualmente, mais da metade dos registros concedidos diz respeito a testes rápidos para anticorpos. Até a presente data, foram registrados 64 testes para diagnóstico da COVID-19, sendo 15 deles moleculares. O teste de polymerase chain reaction em tempo real (RT-PCR) para identificação de SARS-CoV-2 é um teste de elevada sensibilidade e especificidade, ainda que os doentes com maior carga viral possam ter maior probabilidade de um teste positivo. Os testes moleculares baseados em RNA exigem instalações laboratoriais específicas com níveis restritos de biossegurança e técnica. A sensibilidade e especificidade dos testes sorológicos variaram entre os fabricantes. É importante destacar que uma baixa sensibilidade do teste diagnóstico pode resultar em uma maior probabilidade de detectar falsos-negativos, o que poderia interferir principalmente em casos de indivíduos assintomáticos. Em geral, a sensibilidade dos testes foi superior a 85% e a especificidade, superior a 94%. Os testes sorológicos medem a quantidade de dois anticorpos (IgG e IgM) que o organismo produz quando entra em contato com um invasor. Contudo, o desenvolvimento da resposta de um anticorpo à infecção pode ser dependente do hospedeiro e levar tempo. No caso de SARS-CoV-2, estudos iniciais sugerem que a maioria dos pacientes se converte entre 7 e 11 dias após a exposição ao vírus, embora alguns pacientes possam desenvolver anticorpos mais cedo. Devido a esse atraso natural, o teste de anticorpos pode não ser útil no cenário de uma doença aguda (11). Os testes de anticorpos para SARS-CoV-2 podem facilitar (i) o rastreamento de contatos (os testes baseados em RNA também podem ajudar); (ii) a vigilância sorológica nos níveis local, regional, estadual e nacional; e (iii) a identificação de quem já teve contato com o vírus e, portanto, pode (se houver imunidade protetora) ser imune (11,12). Alguns conjuntos de reagentes para testes sorológicos foram autorizados pela ANVISA em caráter emergencial devido à gravidade da situação e à necessidade de ampliar a testagem da população, mas a validação desses reagentes pelos laboratórios é fundamental, uma vez que poucos trabalhos conseguiram ser publicados até o momento. As aprovações estão de acordo com a Resolução da Diretoria Colegiada (RDC) 348/2020, que define os critérios e os procedimentos extraordinários e temporários para tratamento de petições de registro de medicamentos, produtos biológicos e produtos para diagnóstico in vitro, e mudança pós-registro de medicamentos e produtos biológicos em virtude da emergência de saúde pública internacional decorrente do novo coronavírus. Na RDC, para registro de testes diagnósticos, a ausência de qualquer estudo de desempenho ou restrição de dados deve ser justificada por motivações técnicas que permitam a avalição da confiabilidade dos resultados e da efetividade diagnóstica do produto. Os registros concedidos nas condições dessa Resolução terão a validade de um ano, exceto para situações em que a avaliação da estabilidade seja apresentada por comparação com produtos similares e os demais critérios descritos no Regulamento sejam atendidos. Nesse caso, poderão ter a concessão regular de validade de registro de produtos para saúde por um período de 10 anos. Em resumo, as duas categorias de testes para SARS-CoV-2 podem ser úteis nesse surto, pois, eventualmente, a coleta de múltiplas amostras, regiões e em tempos diferentes durante a evolução da doença pode ser necessária para o diagnóstico da COVID-19.


Subject(s)
Humans , Enzyme-Linked Immunosorbent Assay/instrumentation , Chromatography, Affinity/instrumentation , Fluorescent Antibody Technique/instrumentation , Coronavirus Infections/diagnosis , Reverse Transcriptase Polymerase Chain Reaction/instrumentation , Technology Assessment, Biomedical , Health Evaluation
20.
Rev. chil. infectol ; 37(3): 276-280, jun. 2020. tab, graf
Article in English | LILACS | ID: biblio-1126120

ABSTRACT

Abstract The global shortage of reagents and kits for nucleic acid extraction and molecular detection of SARS-CoV-2 requires new cost-effective strategies for the diagnosis of suspected COVID-19 cases, especially in countries that need to increase detection capacity. Pooled nucleic acid testing has been extensively used as a cost-effective strategy for HIV, HepB, HepC and influenza. Also, protocols dispensing of RNA extraction appears as an attractive option for detection of SARS-CoV-2. In this study, we found that pooling of 5 samples showed that CT variations were in the range of 1.0-4,5 units, with less likelihood of a false negative result. Results of the sample without nucleic acid ex-traction, was unsatisfactory, with a significant increase in CT values, and thus for risk of a false negative result. In conclusion, pooling nasopharyngeal samples with both automated and manual extraction proved reliable, and thus a potential efficient alternative for the diagnosis of suspected COVID-19 in developing countries.


Resumen La escasez mundial de reactivos para la extracción de ácidos nucleicos y la detección molecular de SARS-CoV-2 requiere de nuevas estrategias de mayor rendimiento para el diagnóstico de casos sospechosos de COVID-19, especialmente en países que necesitan aumentar su capacidad diagnóstica. La detección de ácidos nucleicos en muestras agrupadas o pool testing se ha utilizado ampliamente como una estrategia costo-efectiva para el VIH, hepatitis B, hepatitis C e influenza. Adicionalmente, los protocolos que no requieren extracción de ARN aparecen como una opción para la detección de SARS-CoV-2. En este trabajo, presentamos los resultados de una estrategia detección de SARS-CoV-2 en muestras agrupadas, que incluye diferentes métodos de extracción de ARN que puede ser una estrategia atractiva para los países en desarrollo. La agrupación de 5 muestras mostró variaciones CT en el rango de 1,0 a 4,5 unidades, con una baja probabilidad de obtener falsos negativos, a diferencias de los resultados agregando muestras agrupadas directamente en la reacción de amplificación de SARS-CoV-2. En conclusión, la agrupación de muestras nasofaríngeas, demostró ser un método confiable y, por lo tanto, una alternativa para aumentar el rendimiento en el diagnóstico de COVID-19 para países en desarrollo.


Subject(s)
Humans , Pneumonia, Viral/diagnosis , Coronavirus Infections/diagnosis , Pandemics , RNA, Viral , Clinical Laboratory Techniques , Reverse Transcriptase Polymerase Chain Reaction , Developing Countries
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