Apport du scanner thoracique dans le dépistage des cas suspects de COVID-19 au Service d'imagerie médicale du Centre Hospitalier et Universitaire (CHU) de Libreville - Gabon / Contribution of chest ct-scan in the screening of suspected cases of COVID-19 at the Medical Imaging Department

Objectifs.Evaluer l'apport de la TDM thoracique dans le diagnostic de la COVID-19 chez les patients suspects en prenant comme référence le Test RT ­PCR et secondairement déterminer les anomalies scanographiques caractéristiques associés au Test RT ­PCR.Matériels etméthodes.Il s'est agi d'une étude rétrospective, descriptive à visée analytique, menée au service d'imagerie du CHU de Libreville. Aux vues de la disponibilité des dossiers nous avons exploité ceux de la période d'activité de mars à juin 2020, soit une période quatre mois. Cette étude a inclus tous les patients ayant une infection à COVID-19 confirmée par la réaction de polymérase en chaine en temps réel (RT ­PCR), après écouvillonnages nasal et/ou pharyngé et / ou les signes typiques de la pneumonie à COVID-19. Pour déterminer les anomalies scanographiques caractéristiques de la COVID-19 associées au test RT ­PCR nous avons comparé 25 patients avec un test RT ­PCR négatifs et 119 patients avec un test RT ­PCR positifs. Une valeur de p < 0,05 était considérée comme significative. La sensibilité de la TDM thoracique a été calculée à l'aide de la relation, Sensibilité=VP/ (VP+FN), (VP : vrai positif de la TDM : TDM positive et test RT PCR positif ; et le FN : Faux négatif de la TDM : TDM négative et test RT PCR positif). L'analyse statistique a été rendu possible grâce au logiciel SPSS 25. Résultats. En régression logistique multivariée, les anomalies scanographiques caractéristiques de la COVID-19 positivement associés à un test RT ­PCR positif étaient :verre dépoliOR = 33,236, IC95% [6,939 ­59,192], p=0,0001), la condensation alvéolaire (OR = 8,093 [1,488 ­44,013]; p=0,016). La sensibilité du scanner thoracique pour le diagnostic de la COVID-19, chez les patients suspects était de 93,2%, la spécificité de 64,2% avec une valeur prédictive positive de 90,2% et une valeur prédictive négative de 73,0%.Conclusion.Le diagnostic scanographique de la COVID-19 chez les patients suspects est aisé avec une bonne sensibilité et spécificité. La présence des anomalies scanographiques caractéristiques à type de verre dépoli et de condensation alvéolaire est associéeà un test RT ­PCR positif

Objective. Evaluate the contribution of Thoracic CT in the diagnosis of COVID-19 in suspected patients by taking the RT ­PCR Test as a reference and secondarily determine the impact of the RT ­PCR Test on characteristic scan abnormalities, in the service of thoracic imaging at Libreville University Hospital.Materials and methods. This was a retrospective, descriptive study with an analytical aim. In view of the availability of files, we used those from the period of activity from March to June 2020, i.e. a four-month period. To determine the impact of the RT ­PCR test on characteristic scan abnormalities, we compared 25 patients with negative RT ­PCR and 119 patients with negative RT ­PCR. A value of p < 0.05 was considered significant. The sensitivity of chestCT was calculated using the relationship, Sensitivity=VP/(VP+FN), (VP: true positive of CT: positive CT and positive RT PCR test; and FN: False negative CT: negative CT and positive RT PCR test). Statistical analysis was made possible using SPSS 25 software.Results. In multivariate logistic regression, CT abnormalities characteristic of COVID-19 were positively associated with a positive RT ­PCR: ground glass, (OR = 33.236, 95% CI [6.939 ­59.192], p = 0.0001), condensation alveolar (OR = 8.093 [1.488 ­44.013]; p = 0.016). The sensitivity of chest CT for the diagnosis of COVID-19 in suspected patients was 93.2%, the specificity of 64.2% with a positive predictive value of 90.2% and a negative predictive value of 73. 0%.Conclusion. CT diagnosis of COVID-19 in suspected patients is easy with good sensitivity and specificity. The presence of characteristic scan abnormalities such as ground glass and alveolar condensation is associated with a positive RT ­PCR tes

The time to negative conversion among adult COVID-19 patients on Chronic Hemodialysis admitted at the Philippine General Hospital — A retrospective cohort study

Objectives@#In the Philippines, patients on chronic hemodialysis with COVID-19 remain admitted in hospitals despite clinical recovery because most free-standing dialysis units require proof of negative conversion via Reverse Transcriptase – Polymerase Chain Reaction (RT-PCR). This study aims to determine the time to negative conversion of COVID-19 RT-PCR testing among adult patients on chronic hemodialysis with COVID-19 admitted at the Philippine General Hospital (PGH) and bring insight in using the symptom or time-based procedure as recommended by local guideline, and ultimately, to ensure delivery of adequate hemodialysis despite being infected with COVID-19, shorten isolation period, and conserve resources especially in resource-limited settings.@*Methods@#This is a retrospective cohort study on all adult patients on chronic hemodialysis who were admitted in PGH after the diagnosis of COVID-19 by RT-PCR between March 2020 and February 2021. Descriptive statistics was used in summarizing the data.@*Results@#A total of 90 patients on chronic hemodialysis who tested positive for COVID-19 via RT-PCR admitted at PGH were included in the study. Most of these patients had moderate COVID-19 at 53.3%. The median number of days from onset of symptoms to clinical recovery was 14.5 days. The median time to first negative conversion was 18 days. Most of these patients had negative conversion at the second week. The correlation coefficient between time to clinical recovery and negative conversion was 0.214. @*Conclusion@#Among adult patients on chronic hemodialysis who were admitted in PGH after the diagnosis of COVID-19, the time to negative conversion was longer compared to the time to clinical recovery with a very weak correlation between the two.

Detection of arboviruses in Aedes aegypti through transovarian analysis: A study in Goiânia, Goiás

Abstract Background: Arboviral diseases are a group of infectious diseases caused by viruses transmitted by arthropods, mainly mosquitoes. These diseases, such as those caused by the dengue (DENV), Zika (ZIKV), chikungunya (CHIKV), and yellow fever (YFV) viruses, have a significant impact worldwide. In this context, entomological surveillance plays a crucial role in the control and prevention of arboviruses by providing essential information on the presence, distribution, and activity of vector mosquitoes. Based on entomological surveillance, transovarian transmission provides information regarding the maintenance and dissemination of arboviruses. The objective of this study was to detect these arboviruses in Goiânia, Goiás, and analyze the occurrence of transovarian transmission. Methods: Aedes aegypti eggs were collected from different regions of Goiânia and cultivated under controlled laboratory conditions until the emergence of adult mosquitoes. Adult females were grouped into pools containing their heads and thoraxes. These pools were subsequently evaluated using reverse-transcription quantitative polymerase chain reaction (RT-qPCR) assay. Results: A total of 157 pools (N=1570) were analyzed, with two pools testing positive for CHIKV and one pool testing positive for ZIKV, indicating that the offspring resulting from transovarian transmission are potentially infectious. Conclusions: In summary, the demonstration of the vertical transmission mechanisms of CHIKV and ZIKV in A. aegypti serves as an alert to health authorities, as these diseases are still underreported, and their primary urban vector has likely acquired this capacity, contributing to the dissemination of these infections.

Cuantificación de la expresión del gen amo-A en poblaciones bacterianas y archaeales presentes en muestras de suelos de un lote arrocero caracterizado por ambientes

El ciclo del nitrógeno representa uno de los procesos biogeoquímicos más importantes para los ecosistemas terrestres y acuáticos. Las comunidades microbianas desempeñan un papel crucial en los procesos de transformación del nitrógeno en el suelo, ya que participan en diversas etapas como la nitrificación, de gran importancia para la producción agrícola. Dentro de los marcadores moleculares más utilizados para evaluar la actividad de poblaciones microbianas oxidantes de amonio se han considerado ampliamente los genes que codifican enzimas claves como la subunidad A de la actividad amonio monooxigenasa (AMO). Sin embargo, no se comprende completamente si la expresión de esta enzima tiene relación directa con el rendimiento de los cultivos. En este contexto, se evaluó la expresión del gen amo-A de comunidades bacterianas y archaeales presentes en un lote arrocero previamente caracterizado por ambientes. Para cuantificar la abundancia de arqueas y bacterias oxidantes de amonio, (AOA y AOB, respectivamente) se emplearon las técnicas de PCR en tiempo real (RT-qPCR) y PCR digital (RT-dPCR). En este trabajo se encontró a través del análisis de datos metagenómicos que hubo una mayor presencia de AOB en las muestras de suelo rizosférico mientras que las AOA fueron predominantes en las muestras de suelo de soporte "bulk", sin embargo, no se detectó la expresión del gen amo-A asociada a la comunidad de bacterias en las muestras de suelo analizadas. Por otra parte, no se presentaron diferencias entre los transcritos del gen amo-A asociados a la comunidad de AOA de los ambientes caracterizados. Además, la expresión de transcritos no estuvo relacionada con alguna de las propiedades químicas evaluadas. Finalmente, las estrategias de cuantificación para RT-qPCR (plásmido y templete) resultaron ser homólogas y funcionales para identificar la expresión del gen amo-A de AOA, mientras que la técnica de RT-dPCR fue más precisa para el análisis de la comunidad de AOB y AOA.

The nitrogen cycle represents one the most important biogeochemical process for terrestrial and aquatic ecosystems. Microbial communities play a crucial role in the processes of transformation of soil nitrogen in the, since they participate in various stages such as nitrification, which is of great importance for agricultural production. Among the most used molecular markers to assess ammonium oxidizing microbial populations activity have been considered widely the genes encoding key enzymes such as ammonium monooxygenase (AMO) subunit A. However, it is not fully understood whether the expression of this enzyme is directly related to the crop yield. In this context, this research work evaluated the expression of the amo-A gene of bacterial and archaeal communities present in a rice field previously characterized by environments. Real-time PCR (RT-qPCR) and digital PCR (RT-dPCR) techniques were used to quantify the abundance of archaea and ammonium-oxidizing bacteria (AOA and AOB, respectively). In this work it was found that in the analysis of metagenomic data there was a greater presence of AOB in rhizospheric soil samples while AOA were predominant in bulk soil samples, however, the expression of the amo-A gene was not detected. associated with the community of bacteria in the soil samples analyzed. On the other hand, it was found that the transcripts of the amo-A gene of the AOA community did not present differences between the characterized environments. Furthermore, the expression of transcripts is not related to any of the chemical properties evaluated. Finally, the quantification strategies for RT-qPCR (plasmid and quenching) turned out to be homologous and functional to identify the expression of the AOA amo-A gene, while the RT-dPCR technique was more precise for the analysis of the community of AOB and AOA.

Estudio comparativo entre un test de antígeno y la prueba de la reacción en cadena de la polimerasa en tiempo real (RT-PCR) para el diagnóstico de infección por COVID-19 en pediatría / Comparative study between an antigen test and the reverse transcription-polymerase chain reaction (RT-PCR) test for the diagnosis of COVID-19 in pediatrics

Introducción. La pandemia por COVID-19 ha puesto de manifiesto la necesidad de pruebas diagnósticas rápidas. La prueba de referencia es la reacción en cadena de la polimerasa en tiempo real (RT-PCR). Requiere un equipo y personal capacitado, y su resultado puede llevar un tiempo de espera prolongado. El sistema BD Veritor® es el método rápido cromatográfico utilizado para la detección del antígeno del coronavirus de tipo 2 del síndrome respiratorio agudo grave, en individuos sintomáticos. El objetivo primario del siguiente trabajo es evaluar sensibilidad y especificidad del test de antígeno (TA) comparadas con la RT-PCR en población pediátrica. Población y métodos. Estudio prospectivo, de prueba diagnóstica. Se incluyó a todo menor de 17 años en los primeros 5 días de inicio de síntomas, que consultó desde julio de 2021 hasta febrero de 2022. Se calculó un mínimo de 300 muestras para lograr una precisión de ± 8,76 % y de ± 3,68 % para sensibilidad y especificidad respectivamente. Se analizaron en paralelo las muestras por ambas metodologías. Resultados. De 316 muestras pareadas, 33 fueron positivas por ambos métodos; 6 fueron positivas solo por RT-PCR. La especificidad del TA fue del 100 %; la sensibilidad, del 84,6 %, con un valor predictivo positivo y negativo del 100 % y del 98 % respectivamente. Conclusiones. El TA demostró ser útil en el diagnóstico de pacientes pediátricos con COVID-19 en los primeros 5 días de inicio de síntomas, aunque aquellos con TA negativo y alta sospecha clínica deberían confirmar su resultado con la RT-PCR.

Introduction. The COVID-19 pandemic has brought to light the need for rapid diagnostic tests. The gold standard test is reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR requires equipment and trained personnel, and results may take a long waiting time. The BD Veritor® System is a rapid chromatographic method used for the detection of severe acute respiratory syndrome coronavirus 2 antigen in symptomatic individuals. The primary objective of this study is to assess the sensitivity and specificity of the antigen test (AT) compared to the RT-PCR in the pediatric population. Population and methods. Prospective study with a diagnostic test. All children younger than 17 years in the first 5 days of symptom onset, who consulted between July 2021 and February 2022, were included. A minimum of 300 specimens was estimated to achieve an accuracy of ±8.76% and ±3.68% for sensitivity and specificity, respectively. Specimens were analyzed in parallel using both methodologies. Results. Of 316 paired samples, 33 were positive by both methods; 6 were positive only by RT-PCR. The specificity of the AT was 100%; sensitivity was 84.6%, with a positive and negative predictive value of 100% and 98%, respectively. Conclusions. The AT proved to be useful in the diagnosis of pediatric patients with COVID-19 in the first 5 days of symptom onset, although those with a negative AT and high clinical suspicion should confirm their result with a RT-PCR.

Material genético do SARS-CoV-2 em superfícies de equipamentos utilizados na prática de atividades físicas / Genetic material of SARS-CoV-2 on the surface of equipment used in the practice of physical activities

A humanidade foi impactada por uma Pandemia que expôs a população ao contato com um vírus de elevado contágio e com o índice de letalidade alarmante. Este estudo objetivou avaliar a possibilidade da persistência de material genético do SARS-CoV-2 na superfície dos equipamentos de estabelecimentos de prática de atividades físicas indoor e outdoor. Foram coleta das amostras de equipamentos utilizados para a prática de exercícios físicos em cinco academias, cinco praças e entre os frequentadores desses ambientes. Aplicou-se a técnica RT-PCR para a detecção doRNA do SARS-CoV-2 e posterior análise dos resultadose foi detectada a existência de partículas de RNA viral do SARS-CoV-2 em 48,57% das amostras coletadas dos equipamentos das academias e 12,85% das amostras coletadas nas praças, evidenciando uma incidência menor em equipamentos utilizados em locais abertos em todas as áreas comparadas.Além disso, constatou-se que 35,7% dos participantes do estudo testaram positivo para COVID-19.Os casos positivos para COVID-19 detectados apresentaram sintomas classificados como levesa moderados e uma recuperação rápida.A presença de material genético nos equipamentos,por sua vez, leva-nos a perceber a importância da higienização adequada das superfícies, como forma de prevenção.

Humanity was impacted by a Pandemic that exposed the population to contact with a highly contagious virus with an alarming lethality rate. The present study aimed to evaluate the possibility of the persistence of genetic material from SARS-CoV-2 on the surface of equipment used to practice indoor and outdoor physical activities. A sample of equipment used for the practice of physical activity was collected in five gyms and five squares and among the regulars of these environments. The RT-PCR technique was applied to detect the RNA of SARS-CoV-2 and subsequent analysis of the results. The existence of SARS-CoV-2 viral RNA particles was detected in 48.57% of the samples collected from gym equipment and 12.85% of the samples collected in squares, evidencing a lower incidence in equipment used in open spaces in all areas compared and it was found that 35.7% of the study participants tested positive for COVID-19. The positive cases for COVID-19 detected, had symptoms classified as mild to moderate and a quick recovery. The presence of genetic material in the equipment, in turn, leads us to realize the importance of proper cleaning of surfaces, as a form of prevention.

Molecular detection of SARS-CoV-2 in Argentina: Evaluation of alternative diagnostic tools for the decentralization of the diagnosis

Abstract The rocketing number of COVID-19 cases highlighted the critical role that diagnostic tests play in medical and public health decision-making to contain and mitigate the SARS-CoV-2 pandemic. This study reports the evaluation and implementation of different tests for the molecular detection of SARS-CoV-2 in the central region of Argentina. We evaluated 3 real time RT-PCR kits (GeneFinder COVID-19 Plus RealAmp Kit, DisCoVery SARS-CoV-2 RT-PCR Detection Kit and WGene SARS-CoV-2 RT Detection), 2 nucleic acid extraction methods [MagaBio plus Virus DNA/RNA Purification Kit II (BioFlux), 35-min vs. 9-min, a pre-analytical reagent (FlashPrep®) and 2 isothermal amplification tests (Neokit Plus and ELA CHEMSTRIP®). The order according to the best performance of the 3 real-time RT-PCR kits evaluated was: DisCoVery > GeneFinderTM> WGene. The 2 RNA extraction methods showed similar good results: MagaBio plus Virus RNA Purification Kit II (BioFlux) 9-min was selected due to its faster performance. FlashPrep® reagent showed excellent results to perform direct RNA detection. Isothermal amplification assays showed acceptable sensitivity and specificity values (>80%), except in samples with Ct> 30. Our data show optimal real time RT-PCR kits and alternative molecular methods for SARS-CoV-2 diagnostic. These alternative assays proved to be aceptable.

Resumen La explosión de casos de COVID-19 resaltó el papel fundamental que desempeñan las pruebas de diagnóstico en la toma de decisiones médicas y de salud pública para contener y mitigar la pandemia de SARS-CoV-2. Este estudio reporta la evaluación y la implementación de diferentes test para la detección molecular de SARS-CoV-2 en la región central de Argentina. Evaluamos tres kits de RT-PCR en tiempo real (GeneFinder COVID-19 Plus RealAmp Kit, DisCoVery SARS-CoV-2 RT-PCR Detection Kit y WGene SARS-CoV-2 RT Detection), dos métodos de extracción de ácidos nucleicos (MagaBio plus Virus DNA/RNA Purification Kit II [BioFlux, 35-min vs. 9-min), un reactivo pre-analítico (FlashPrep®) y dos test de amplificación isotérmica (Neokit Plus and ELA CHEMSTRIP®). El orden de rendimiento de los tres kits de RT-PCR en tiempo real evaluados fue el siguiente: DisCoVery GeneFinder™ WGene. Los dos métodos de extracción de RNA mostraron buenos y similares resultados; se seleccionó MagaBio plus Virus RNA Purification Kit II (BioFlux) 9-min debido a su rápido tiempo de procesamiento. El reactivo FlashPrep® mostró excelentes resultados para realizar detección directa de RNA. Los ensayos de amplificación isotérmica mostraron valores de sensibilidad y de especificidad aceptables (80%), excepto en muestras con Ct 30. Nuestros resultados muestran kits de RT-PCR en tiempo real óptimos, como así también métodos moleculares alternativos para el diagnóstico de SARS-CoV-2 que resultan aceptables para su uso en contextos adversos, de descentralización y en diferentes escenarios epidemiológicos, para la detección rápida y precisa del SARS-CoV-2.

Improvement of bovine pestiviral diagnosis by the development of a cost-effective method for detecting viral RNA in fresh specimens and samples spotted in filter papers / Optimización del diagnóstico de Pestivirus bovinos mediante el desarrollo de una metodología económica para detectar ARN viral en muestras frescas y fijadas en papeles de filtro

Abstract Bovine pestiviruses are the causative agents of bovine viral diarrhea, a disease thatcauses severe economic losses in cattle. The aim of this study was to improve their diagnosisby developing a RT-qPCR to detect bovine pestiviruses A, B and H; and to set up a protocolfor collecting, shipping and preserving bovine pestiviral RNA on filter papers. The developedRT-qPCR showed high sensitivity in detecting these viruses in different matrices: viral stocks,semen and serum samples. With regard to the possibility of using the technique to test serumpools, it was possible to identify a positive serum sample within a pool containing 30 sera.In addition to evaluating the qPCR from fresh samples, the use of filter papers to sow bovinesamples was analyzed. The sampling method on two different filter papers using bovine blooddrops was a useful alternative for diagnostic purposes and allowed to preserve pestiviral RNAfor up to 12 months under refrigeration.

Resumen Los Pestivirus bovinos son los agentes causales de la diarrea viral bovina, una enfermedad que genera importantes pérdidas económicas en el ganado vacuno. El objetivo de este trabajo fue mejorar su diagnóstico mediante el desarrollo de una RT-qPCR para detectar los Pestivirus bovinos A, B y H y disenar un protocolo de recolección, envío y conservación de ARN viral en papeles de filtro. La RT-qPCR desarrollada demostró alta sensibilidad en la detección de estos virus en diferentes matrices: stock viral, suero y semen. Respecto de la posibilidad de usar la técnica para testear pools de suero, fue posible identificar un suero positivo dentro de un pool compuesto por 30 sueros. Además de evaluar la qPCR en muestras frescas, se analizó el uso de papeles de filtro para sembrar muestras de bovinos. La metodología de toma de muestras en dos tipos de papeles de filtro usando gotas de sangre fue una alternativa útil para el diagnóstico y permitió conservar ARN viral por hasta 12 meses a temperaturas de refrigeración.

Real-world outcomes and complications of different surgical approaches for significant submacular haemorrhages

Purpose: To evaluate the outcomes and complications after different surgical management of cases with significant sumacular hemorrhage (SMH) of size more than 4 disc diameter (DD). Methods: It was a retrospective interventional study. All consecutive 103 cases of significant SMHs were treated by vitrectomy and divided into three groups. In Group A (<4 weeks, confined to the macula or extending inferiorly, n = 62), vitrectomy, subretinal cocktail of tissue plasminogen activator (tPA), antivascular endothelial growth factor, and air with SF6 gas; in Group B (4–8 weeks, extending beyond macula, n = 31), subretinal tPA followed by SMH drainage either by retinotomy (Group B?1, n = 17) or by temporal 180?degree retinectomy (Group B?2, n = 14) with silicone oil (SO) tamponade; and in Group C (>8 weeks, extending beyond macula, n = 10), SMH removal with autologous retinal pigment epithelium (RPE)?Choroid patch graft transplantations with SO tamponade were performed. Parameters evaluated were best corrected visual acuity (BCVA), Optos, optical computerized tomography, and ultrasonography as required. Results: Significant visual improvement was seen from mean preoperative to mean postoperative BCVA in Group A (P < 0.001), Group B (P < 0.001), and Group C (P < 0.001). Postoperative complications were recurrent SMH (4.84% vs 12.90% vs 10%), vitreous hemorrhage (6.45%, GroupA), hyphema (4.84% vs 12.90% vs 10%), hypotony (nil vs 3.23% vs 20%), macular hole formation (6.45%, Group A), epiretinal membrane (16.13%, Group B), and retinal detachment (3.23%, Group A and 10%, Group C). Conclusion: Surgical approaches for significant submacular hemorrhage are visually awarding, though certain specific complications may arise

ASSOCIATION OF SERUM FERRITIN IN POST COVID-19 ANAEMIC PATIENTS TREATED WITH UMBILICAL CORD BLOOD AND HAEMATINICS.

COVID-19 patients commonly present with lower respiratory symptoms with other systemic involvement. Haematological manifestation such as low haemoglobin, thrombocytopenia, lymphocytopenia also common in COVID19 patients. In this study, we investigated prevalence, association with serum ferritin in post COVID-19 anaemic patients, after human umbilical cord blood transfusion in relation to control group. Among 155 COVID-19 RT-PCR positive patients 36 (23%) was anaemic. In our study 18 patients was transfused human umbilical cord blood, 12 patients were treated with haematinics and 6 patients denied taking any of the above. In most cases anaemia was moderate to severe that may be due to inflammation or due to pre-existing iron deficiency.Umbilical cord blood transfusion to post COVID -19 patients for the treatment of anaemia because of the unique composition of UCB. Haematological analysis and serum ferritin estimation reflecting the treatment out come in post COVID-19 anaemic patients. There was a difference between the dependent variable's serum ferritin (p <.001) in anaemic COVID-19 patients. In conclusion, our result highlight serum ferritin is widely used in diagnosis and monitoring of COVID-19 disease.

Lactic Acid Inhibits the Cytotoxicity of NK-92 Cells via Activating the Lactate Receptor GPR81

Aims: Lactate acid functions as not only an energy source but a signaling molecule through the lactate receptor GPR81 under physiological conditions. However, the pathological role of lactic acid in the tumor microenvironment remains unclear, particularly for immune cells. Methodology: NK-92 cells were treated with L-lactic acid solutions at final concentrations of 10, 20, 30, and 40 mM, and its cell viability and cytotoxicity on A549 cells and A375 cells were evaluated by CCK8 assay and crystal violet assay, respectively. Furthermore, qPCR was used to assess the expression of GPR81 and cytotoxicity-related genes in NK-92 cells treated with antagonist and agonist. And their relationship between lactate/GPR81 pathway and cytotoxicity-related genes were analyzed by Pearson’s correlation. Results: The viability of NK-92 cells was inhibited by L-lactic acid with increasing concentration. Additionally, the cytotoxic activity against tumor cells of NK-92 cells treated with L-lactic acid decreased with increasing concentration. Moreover, qPCR results demonstrated that GPR81 can be activated by lactic acid or agonist (3,5-DHBA) and downregulate the expression cytotoxicity-related genes which included FASLG gene(Fas Ligand),TNF-? gene(Tumor necrosis factor-?), INFG gene (Interferon-?), RPF1 gene (Perforin 1), GZMA gene (Granzyme A), GZMB gene (Granzyme B), GZMH gene (Granzyme H), GAMK gene (Granzyme K) and GZMM gene (Granzyme M). And the expression of GPR81 returned to near-control level when treated with L-lactic acid in the presence of antagonist (3-OBA), the expression of cytotoxicity-related genes did as well. Pearson’s correlation analysis of cytotoxicity-related genes with GPR81 revealed that their correlation coefficient seems negative. Conclusion: Lactic acid can activate the GPR81 to downregulate the expression of cytotoxicity-related genes, subsequently lower the cytotoxicity of NK-92 cells.

SARS-CoV-2 antigen detection in deceased bodies: implications for infection prevention

Background & objectives: High transmissibility of the SARS-CoV-2 has significant implications on healthcare workers’ safety, preservation, handling, transportation and disposal of the deceased bodies. The objective of this study was to detect SARS-CoV-2 antigen in nasopharyngeal samples and its implications in handling and care of COVID-19 deceased bodies. Methods: A study was conducted at a dedicated COVID-19 centre on deceased individuals from April to December 2020. Rapid antigen test (RAT) and reverse transcription (RT)-PCR was compared on all the SARS-CoV-2 positive cadavers recruited in the study. Results: A total of 115 deceased individuals were included in the study. Of these, 79 (68.7%) were male and 36 (31.3%) were female and majority were in the age group of 51-60 yr [31 (27%)]. SARS-CoV-2 antigen test was positive in 32 (27.8%) and negative in 83 (72.1%) individuals. The mean time interval between deaths to the sample collection was 13.2 h with interquartile range of eight to 20 h. Reverse transcription (RT)-PCR was used as the reference test and 24 (20.9%) cases were true positive; 93.6 per cent [95% confidence interval (CI) 88.8-98.4%] sensitivity, 45.2 per cent (95% CI 35.5-55%) specificity, 60.2 per cent (95% CI 50.6-69.8%) positive predictive value and 88.8 per cent (95% CI 82.7-95%) negative predictive value of antigen test was computed. Interpretation & conclusions: SARS-CoV-2 antigen test was positive beyond 19 h in COVID-19 deceased individuals. Antigen test was found to be highly sensitive in the deceased. Patients, suspected of having died due to COVID-19, can be screened by this method. As infectiousness of the virus in the deceased bodies cannot be directly concluded from either the antigen or RT-PCR test, yet possible transmission cannot be completely ruled out. Strict infection control measures need to be followed during the handling and clearance of COVID-19 cadavers.

Optimización del control interno de calidad de RT-PCR en tiempo real para detección cualitativa de SARS-CoV-2

Objetivo: Optimizar el control interno de calidad de RT-PCR en tiempo real para detección cualitativa de SARS-CoV-2, utilizando los valores Cq de controles negativos y positivos. Material y método: Estudio prospectivo-longitudinal. La muestra estuvo constituida por 143 valores Cq para los controles negativos de alicuotado y extracción, así como para el control positivo. Se analizó la distribución normal de los valores Cq mediante la prueba de Anderson-Darling (AD) y se aplicaron pruebas de aleatoriedad. Se calculó límites de control a partir de 51 valores Cq, para luego, mediante gráficas de control, monitorizar 92 valores Cq obtenidos desde noviembre del 2020 hasta marzo del 2021. Se evaluó aceptación de lote e índices Cpk como indicadores de optimización. Los cálculos se hicieron con el programa Minitab. Resultados: Se aceptaron los lotes de valores Cq y se obtuvieron índices Cpk superiores a 1.33 para los tres tipos de control. Discusión: No existen estudios publicados que apliquen control estadístico de calidad a la detección cualitativa de SARS-CoV-2. Conclusiones: Es posible utilizar los valores Cq de los controles para optimizar el control interno de calidad de RT-PCR en tiempo real para detección cualitativa de SARS-CoV-2, como si se tratara de una técnica de tipo cuantitativo.

Objective: To optimize the internal quality control of real-time RT-PCR for the qualitative detection of SARS-CoV-2, using the Cq values ​​of negative and positive controls. Material and method : Prospective-longitudinal study. The sample consisted of 143 Cq values for the negative aliquot and extraction controls, as well as for the positive control. The normal distribution of Cq values ​​was analyzed using the Anderson-Darling (AD) test and randomness tests were applied. Control limits were calculated from 51 Cq values, and then, using control charts, to monitor 92 Cq values ​​obtained from November 2020 to March 2021. Lot acceptance and Cpk indices were evaluated as optimization indicators. The calculations were made with the Minitab program. Results: The batches of Cq values ​​were accepted and Cpk indices higher than 1.33 were obtained for the three types of control. Discussion : There are no published studies that apply statistical quality control to the qualitative detection of SARS-CoV-2. Conclusions : It is possible to use the Cq values ​​of the controls to optimize the internal quality control of real-time RT-PCR for qualitative detection of SARS-CoV-2, as if it were a quantitative technique.

Uma análise dos principais diagnósticos de Sars-cov-2 disponíveis no Brasil: uma revisão de literatura / Diagnosis and main types of coronavirus in humans: a narrative review / Diagnóstico y principales tipos de coronavirus en humanos: una revisión narrativa

Introdução: Com a emergência do SARS-CoV-2 foi disponibilizado uma grande quantidade de ferramentas de diagnóstico. Neste contexto, a falta de vacina, de tratamento e o grande número de casos graves e morte, possibilitou a aprovação emergencial de diversos testes, que ainda necessitam de estudos populacionais para seu registro definitivo. Objetivo: Realizar uma revisão de literatura para avaliar as metodologias de diagnóstico disponíveis no Brasil, de acordo com a realidade local de saúde, explorando o momento epidemiológico a complexidade do teste e a finalidade da sua aplicação. Metodologia: Trata-se de um estudo bibliográfico, descritivo do tipo revisão de literatura. Foram utilizadas as seguintes bases de dados científicos para buscas: PUBMED, MEDLINE, LILACS E COCHRANE LIBRARY, através de descritores selecionados na plataforma DECS. Resultados: O cenário de diversos ensaios, baseados em diferentes metodologias, como os testes baseados em RNA viral, em detecção de antígenos virais ou de anticorpos, associados ao conhecimento da história natural do vírus, possibilita uma análise crítica do melhor diagnóstico de acordo com a clínica do paciente, os epidemiológicos, o objetivo do diagnóstico e a acurácia do ensaio. Atualmente, há mudança no padrão imunológico da população e a descrição de tipos e subtipos de SARS-CoV-2 com mudanças gênicas, que podem levar a mudanças na acurácia diagnóstica ou a re-emergência em surtos de doença grave. Conclusão: Ainda é incerto o caminho evolutivo da história natural da Covid-19 e os ensaios diagnósticos estão em diferentes estágios de desenvolvimento, validação e produção e cada tipo de teste tem suas próprias vantagens e desvantagens distintas inerentes a plataforma tecnológica de origem e uma combinação de tipos de testes usados em momentos diferentes pode ser útil para a condução clínica dos pacientes e no controle da pandemia por SARS-CoV-2.

Introduction: With the emergence of SARS-CoV-2, a large number of diagnostic tools were made available. In this context, the lack of vaccine, treatment and the large number of severe cases and death, allowed the emergency approval of several tests, which still require population studies for their definitive registration. Objective: To carry out a literature review to evaluate the diagnostic methodologies available in Brazil, according to the local health reality, exploring the epidemiological moment, the complexity of the test and the purpose of its application. Methodology: This is a bibliographic, descriptive study of the literature review type. The following scientific databases were used for searches: PUBMED, MEDLINE, LILACS AND COCHRANE LIBRARY, through selected descriptors on the DECS platform. Results: The scenario of several tests, based on different methodologies, such as tests based on viral RNA, on detection of viral antigens or antibodies, associated with knowledge of the natural history of the virus, allows a critical analysis of the best diagnosis according to the patient's clinical, epidemiological, diagnostic objective and assay accuracy. Currently, there is a change in the immune pattern of the population and the description of types and subtypes of SARS-CoV-2 with genetic changes, which can lead to changes in diagnostic accuracy or the re-emergence in outbreaks of severe disease. Conclusion: The evolutionary path of the natural history of Covid-19 is still uncertain and diagnostic assays are at different stages of development, validation and production and each type of test has its own distinct advantages and disadvantages inherent in the technology platform of origin and a combination of types of tests used at different times can be useful for the clinical management of patients and in the control of the SARS-CoV-2 pandemic.

Introducción: Con la aparición del SARS-CoV-2, se dispuso de un gran número de herramientas diagnósticas. En este contexto, la falta de vacuna, tratamiento y el gran número de casos graves y muerte, permitieron la aprobación de urgencia de varias pruebas, que aún requieren estudios poblacionales para su registro definitivo. Objetivo: Realizar una revisión bibliográfica para evaluar las metodologías diagnósticas disponibles en Brasil, de acuerdo con la realidad sanitaria local, explorando el momento epidemiológico, la complejidad de la prueba y la finalidad de su aplicación. Metodología: Se trata de un estudio bibliográfico, descriptivo, del tipo revisión de literatura. Para las búsquedas se utilizaron las siguientes bases de datos científicas PUBMED, MEDLINE, LILACS Y COCHRANE LIBRARY, a través de descriptores seleccionados en la plataforma DECS. Resultados: El escenario de varias pruebas, basadas en diferentes metodologías, como pruebas basadas en el ARN viral, en la detección de antígenos virales o anticuerpos, asociado al conocimiento de la historia natural del virus, permite un análisis crítico del mejor diagnóstico de acuerdo con la clínica del paciente, epidemiológica, objetivo diagnóstico y precisión de la prueba. Actualmente, hay un cambio en el patrón inmunológico de la población y la descripción de tipos y subtipos de SARS-CoV-2 con cambios genéticos, que pueden conducir a cambios en la precisión diagnóstica o la reaparición en brotes de enfermedad grave. Conclusiones: El camino evolutivo de la historia natural del Covid-19 es aún incierto y los ensayos de diagnóstico se encuentran en diferentes etapas de desarrollo, validación y producción y cada tipo de prueba tiene sus propias ventajas y desventajas distintas inherentes a la plataforma tecnológica de origen y una combinación de tipos de pruebas utilizadas en diferentes momentos puede ser útil para el manejo clínico de los pacientes y en el control de la pandemia de SARS- CoV-2.

Accuracy of a raw saliva-based COVID-19 RT-LAMP diagnostic assay

ABSTRACT The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic demanded rapid diagnosis to isolate new COVID-19 cases and prevent disease transmission. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) rapidly became the gold standard for diagnosis. However, due to the high cost and delay of the results, other types of diagnosis were implemented, such as COVID-19 Ag Rapid Tests and Reverse Transcription Technique followed by Loop-Mediated isothermal Amplification (RT-LAMP). In this work, we validated the use of RT-LAMP in saliva samples rather than nasopharyngeal swabs, as the collection is more comfortable. First, we selected 5 primer sets based on the limit of detection for SARS-CoV-2 RNA, then validated their sensitivity and specificity in patient samples. A total of 117 samples were analyzed by fluorometric RT-LAMP and compared with qRT-PCR results. Our results show that the use of a high-sensitive primer ORF1-a, together with a low-sensitive primer set Gene E (time to threshold of 22.9 and 36.4 minutes, respectively, using 200 copies of viral RNA), achieved sensitivity in purified RNA from saliva samples of 95.2% (95% CI 76.1-99.8) with 90.5% specificity (95% CI 69.6-98.8) (n = 42).As RNA purification increases the turnaround time, we tested the outcome of RT-LAMP utilizing raw saliva samples without purification. The test achieved a sensitivity of 81.8% (95% CI 59.7-94.8) and a specificity of 90.9% (95% CI 70.8-98.8). As a result, the accuracy of 92.9% (95% CI 80.5-98.5) in purified RNA-saliva samples was lowered to an acceptable level of 86.4% (95% CI 72.6-94.8) in raw saliva. Although mass vaccination has been implemented, new strains and low vaccination progress helped to spread COVID-19. This study shows that it is feasible to track new COVID-19 cases in a large population with the use of raw saliva as sample in RT-LAMP assay which yields accurate results and offers a less invasive test.

Comparative analysis of Respiratory Syncytial Virus frequency rates and viral load in different patient cohorts in a University Hospital in São Paulo, Brazil, over an eight-year period (2005-2013)

Abstract Respiratory Syncytial Virus (RSV) poses a global health concern, particularly affecting young children, the elderly, and immunosuppressed individuals. RSV viral load is essential for understanding transmission, disease severity, prevention, and treatment. This retrospective study aimed to analyze the frequency rates and viral loads of RSV infections in different patient cohorts and age groups over an eight-year period in a university hospital in São Paulo, Brazil. This study analyzed 1380 Immunocompetent (IC) and Immunosuppressed (IS) patients with acute respiratory tract infections. IC included patients with chronic Heart Disease (HD), Primary Care service recipients (PC), and a subgroup suspected of having Severe Acute Respiratory Syndrome caused by Influenza A (H1N1)pdm09 virus (SARS H1N1). IS comprised transplant patients and those with HIV infection. Respiratory samples were collected between February 2005 and October 2013, with RSV detection and viral load quantification (Log10 copies of RNA/mL) using RT-qPCR. Overall RSV infection rate was 17.3 %, with higher rates in children (23.9 %) than in adults (12.9 %), particularly in children under two years of age (28.2 %). Children in the SARS H1N1 and PC subgroups had higher infection rates (16.4 % and 34.9 %, respectively), with the highest rate in PC children aged 1 to < 2 years (45.45 %). Adults with HD had a significantly higher frequency rate (27.83 %) than those in the SARS H1N1 (2.65 %) and IS (15.16 %) subgroups and higher hospitalization rate among adults under 65 years. RSV viral load ranged from 2.43 to 10.15 Log10 RNA copies/mL (mean ± SD 5.82 ± 2.19), with hospitalized patients exhibiting significantly higher viral loads (7.34 ± 1.9) than outpatients (4.38 ± 1.89). Elderly bone marrow transplant patients also had significantly higher viral loads (7.57 ± 2.41) than younger adults (5.12 ± 1.87). This study provides insights into the RSV infection patterns in different patient cohorts in Brazil. Further investigations are needed to understand susceptibility and risk factors associated with RSV infection. In conclusion, high RSV viral load among hospitalized patients could serve as a surrogate marker of disease severity. Additionally, patients with chronic heart disease deserve greater attention regarding complications associated with RSV infection.

Mapping of SARS-CoV-2 in Waldeyer's lymphatic ring and visceral biopsies: the age and the illness duration's impact

Abstract Objective: To study the impact of age and the interval between disease diagnosis and death on the organotropism of SARS-CoV-2. Method: Patients underwent post-mortem biopsies from lungs, Waldeyer ring, heart, liver, kidneys and bone marrow between 2020-2021. SARS-CoV-2 organotropism was mapped by using molecular RT-PCR analyses for SARS-CoV2 targeting the Envelope gene (E), the RNA Polymerase Gene (RdRp), and the Nucleocapsid gene (N). Statistical and linear regression analysis was performed to study the impact of age and illness duration in SARS-CoV-2 organotropism. Results: We performed 158 postmortem biopsies in 21 patients, with a mean age of 76 years old. The mean interval between the diagnosis of the infection to the death was 23 days. The RNA of the SARS-CoV-2 was detected in 100% of lung biopsies, 76%-82% of Waldeyer's ring biopsies, 55% of heart biopsies, 40% of kidney biopsies, 33% of liver and 25% of bone marrow biopsies. Patients who died before the day 9, presented extensive visceral dissemination of SARS-CoV-2 RNA. Most of the patients older than 80 years (90%) presented visceral dissemination of SARS-CoV-2 RNA, while among younger patients, only 3/11 patients presented visceral dissemination of the virus. The relationship between "age" and "illness duration" and multitropism of the virus was statistically significant (p< 0.001). Conclusion: Disease interval and age were factors that were significantly associated with RT-PCR positive results in multiple organs. Critical COVID-19 patients have multiorganic viral dissemination in early stages. In the critical older patients, multiorganic viral dissemination is the rule. Level of evidence: 4. Case Series.

Clinical significance of LncRNA-MIAT as a non-invasive diagnostic marker of nonHodgkin's lymphoma associated with occult hepatitis C virus infection

Aims: the current research aimed to investigate LncRNA-MIAT in patients with nonHodgkin lymphoma (NHL) and to assess its correlation with clinicopathological features and treatment protocols of NHLs among Egyptian patients with Occult hepatitis C virus (HCV) infection (OCI). Patients & Methods: This study was conducted on 20 patients with NHL and 30 healthy subjects as the control group. All subjects were screened for HCV-RNA in both plasma and PBMCs. RT-PCR determined lncRNA-MIAT. Results: lncRNA-MIAT relative expression level was upregulated in NHL groups (2.73±0.86) compared to controls (1.06±0.07), P ˂0.001*. Among NHL, patients with OCI (3.2±0.63) had significantly higher levels of lncRNA-MIAT compared to HCV (2.6±1.08) and non-HCV (2.4±0.4), P ˂0.001*. Additionally, the relative expression levels of lncRNA-MIAT were significantly positively correlated with laboratory and clinicopathological features of NHL. Interestingly, concerning the treatment of DLBCLNHL, there were significantly higher levels of lncRNA-MIAT in no treatment subgroup (n=10, 3.31±0.95) compared to successfully treated subgroups [CHOP (n=7, 1.58±0.34) and R-CHOP (n=3, 11.16±0.21), P ˂0.001* Conclusions: lncRNA-MIAT level was upregulated in NHL patients, particularly patients with OCI. Thus, circulatory lncRNA-MIAT may serve as a promising non-invasive diagnostic marker for NHL associated with OCI

Delayed SARS-COV-2 clearance in infected persons in Ghana

Objective: This study aimed to determine the duration of SARS-CoV-2 clearance in persons in Ghana. The research question was whether the duration of virus clearance in Ghana matched the 14 days recommended by the World Health Organization (WHO); this had direct implications for transmission, which was key in managing the COVID-19 pandemic. Design: This was a retrospective analytical study. Setting: All facilities that submitted clinical specimens to Noguchi Memorial Institute for Medical Research (NMIMR) for SARS-CoV-2 diagnosis between March to June 2020 were included in the study. Interventions: Samples from 480 persons who tested positive for SARS-CoV-2 by RT-PCR from March to June 2020 at NMIMR and submitted at least two follow-up samples were retrospectively analysed. Individuals with two consecutive negative RT-PCR retesting results were considered to have cleared SARS-CoV-2. Results: The median time from the initial positive test to virus clearance was 20 days (IQR: 5-56 days). This was six days longer than the WHO-recommended 14 days, after which infected persons could be de-isolated. Sputum and nasopharyngeal swabs proved more sensitive for detecting viral RNA as the infection progressed. At a significance level of 0.05, age and sex did not seem to influence the time to SARS-CoV-2 clearance. Conclusions: The median time to SARS-CoV-2 clearance in this study was 20 days, suggesting that SARS-CoV-2 infected persons in Ghana take longer to clear the virus. This finding calls for further investigations into whether patients who remain PCR positive continue to be infectious and inform isolation practices in Ghana.

Risque de transmission de certains arbovirus à travers le don de sang à Bamako / Risk of transmission of certain arbovirus through blood donation in the city of Bamako

Introduction. Au Mali, le dépistage de certains virus tels que la dengue, Zika et la fièvre de la vallée du Rift n'est pas systématique au centre national de transfusion sanguine (CNTS). Le risque peut être considérable en raison de leurs courtes périodes de virémie asymptomatique dans la population dont l'incidence est variable et parfois extrêmement élevée. Cette étude avait pour objectif d'explorer la possibilité de transmission de certains arbovirus à travers le don de sang au CNTS de Bamako. Méthodes. Il s'agissait d'une étude transversale, de juillet 2019 à juin 2020 à Bamako. Au total deux cents (200) donneurs de sang du CNTS ont été inclus. Les examens ont été réalisés au Centre d'Infectiologie Charles Mérieux (CICM) de Bamako avec le dépistage du génome des virus responsables de la Dengue, de la fièvre de la Vallée du Rift, et du Zika à l'aide de la technique de la RT-PCR en temps réel. Le Test de Dépistage Rapide (TDR) a été utilisé pour la détection des anticorps IgG et IgM spécifiques de la Dengue. Résultats. Le sexe masculin représente 84% (168/200). Le TDR a détecté 4,5% (9/200) de Dengue IgG positifs et aucun cas de Dengue IgM positif. La technique de RT-PCR n'a détecté aucun des trois virus. Conclusion. Cette étude prouve que le risque de transmission de certains arbovirus à travers le don de sang existe, mais il semble être minime au CNTS de Bamako

Background. In Mali, screening for certain viruses such as dengue, Zika, and Rift Valley fever is not systematic at the national blood transfusion center (CNTS). The risk can be considerable due to their short periods of asymptomatic viremia in the population with variable and sometimes extremely high incidence. The objective of this study was to explore the possibility of transmission of certain arboviruses through blood donation at the CNTS of Bamako. Methods. This was a cross-sectional study, from July 2019 to June 2020 in Bamako. A total of two hundred (200) blood donors from the CNTS were included. The examinations were performed at the Centre d'Infectiologie Charles Mérieux (CICM) in Bamako with the screening of the genome of viruses responsible for Dengue, Rift Valley fever, and Zika using the real-time RT-PCR technique. The Rapid Screening Test (RST) was used for the detection of Dengue-specific IgG and IgM antibodies. Results. Male sex represented 84% (168/200). The RDT detected 4.5% (9/200) of IgG positive Dengue and no IgM positive Dengue cases. The RT-PCR technique did not detect any of the three viruses. Conclusion. This study proves that the risk of transmission of certain arboviruses through blood donation exists, but it seems to be minimal at the CNTS of Bamako.