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Introduction: Pulmonary and extrapulmonary manifestations have been described after infection with SARS-CoV-2, the causative agent of coronavirus disease 2019 (COVID-19). The virus is known to persist in multiple organs due to its tropism for several tissues. However, previous reports were unable to provide definitive information about whether the virus is viable and transmissible. It has been hypothesized that the persisting reservoirs of SARS-CoV-2 in tissues could be one of the multiple potentially overlapping causes of long COVID. Methods: In the present study, we investigated autopsy materials obtained from 21 cadaveric donors with documented first infection or reinfection at the time of death. The cases studied included recipients of different formulations of COVID-19 vaccines. The aim was to find the presence of SARS-CoV-2 in the lungs, heart, liver, kidneys, and intestines. We used two technical approaches: the detection and quantification of viral genomic RNA using RT-qPCR, and virus infectivity using permissive in vitro Vero E6 culture. Results: All tissues analyzed showed the presence of SARS-CoV-2 genomic RNA but at dissimilar levels ranging from 1.01 × 102 copies/mL to 1.14 × 108 copies/mL, even among those cases who had been COVID-19 vaccinated. Importantly, different amounts of replication-competent virus were detected in the culture media from the studied tissues. The highest viral load were measured in the lung (≈1.4 × 106 copies/mL) and heart (≈1.9 × 106 copies/mL) samples. Additionally, based on partial Spike gene sequences, SARS-CoV-2 characterization revealed the presence of multiple Omicron sub-variants exhibiting a high level of nucleotide and amino acid identity among them. Discussion: These findings highlight that SARS-CoV-2 can spread to multiple tissue locations such as the lungs, heart, liver, kidneys, and intestines, both after primary infection and after reinfections with the Omicron variant, contributing to extending knowledge about the pathogenesis of acute infection and understanding the sequelae of clinical manifestations that are observed during post-acute COVID-19.
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Background: The high COVID-19 dissemination rate demands active surveillance to identify asymptomatic, presymptomatic, and oligosymptomatic (APO) SARS-CoV-2-infected individuals. This is of special importance in communities inhabiting closed or semi-closed institutions such as residential care homes, prisons, neuropsychiatric hospitals, etc., where risk people are in close contact. Thus, a pooling approach-where samples are mixed and tested as single pools-is an attractive strategy to rapidly detect APO-infected in these epidemiological scenarios. Materials and Methods: This study was done at different pandemic periods between May 28 and August 31 2020 in 153 closed or semi-closed institutions in the Province of Buenos Aires (Argentina). We setup pooling strategy in two stages: first a pool-testing followed by selective individual-testing according to pool results. Samples included in negative pools were presumed as negative, while samples from positive pools were re-tested individually for positives identification. Results: Sensitivity in 5-sample or 10-sample pools was adequate since only 2 Ct values were increased with regard to single tests on average. Concordance between 5-sample or 10-sample pools and individual-testing was 100% in the Ct ≤ 36. We tested 4,936 APO clinical samples in 822 pools, requiring 86-50% fewer tests in low-to-moderate prevalence settings compared to individual testing. Conclusions: By this strategy we detected three COVID-19 outbreaks at early stages in these institutions, helping to their containment and increasing the likelihood of saving lives in such places where risk groups are concentrated.
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The detection of SARS-CoV-2 and its implication in the diagnosis of COVID-19 have been highly debated in the pandemic. Access to molecular diagnosis and its target population was essential in the public policy. The objective of this study was to evaluate the cost / benefit of detecting SARS-CoV-2 in asymptomatic close contacts using different molecular diagnostic tests. 51 close contacts of people with a diagnosis of SARS-CoV-2 confirmed by RTqPCR, classified by Ct (<20, between 20 and 30 and> 30), were studied in public hospitals in Province of Buenos Aires. Of all contacts studied, 15.7% were confirmed for SARS-CoV-2, there were no contacts of cases with Ct> 30 positive. The number of positive contacts of cases with Ct <20 was significantly higher than that of cases with Cts> 20. Samples with Cts <20 were associated with an estimated viral load of 1 to 4 orders of magnitude difference with Ct ranges> 20. 13.7% of positive close contacts were from cases with Ct <20. When studying positive samples with confirmed diagnosis by PCR, corresponding to EW1 of 2021, only 19.35% corresponded to samples with Cts <20 and 50.7% with Cts between 20 and 30. From these data it is shown that with the close contact test we could detect only 3.7% of cases. The effort by the public health system for this strategy, with low predictive power, may have a negative effect on the fulfillment of the isolation of contacts and could generate a delay in the results of suspected cases, without contributing significantly to controlling the pandemic.
La detección de SARS-CoV-2 y su implicancia en el diagnóstico de COVID-19 han sido muy debatidos en la pandemia. El acceso al diagnóstico molecular y su población destinataria fue parte esencial de las políticas públicas. El objetivo de este estudio fue evaluar el costo/beneficio de la detección de SARS-CoV-2 en contactos estrechos asintomáticos mediante el uso de distintas pruebas de diagnóstico molecular. Se estudiaron 51 contactos estrechos de personas con diagnóstico de SARS-CoV-2 confirmado por RTqPCR, clasificadas por Ct (<20, entre 20 y 30 y >30) en hospitales públicos de la Provincia de Buenos Aires. Del total de contactos estudiados el 15,7% resultó confirmado para SARS-CoV-2, no hubo contactos de casos con Ct>30 positivos. La cantidad de contactos positivos de casos con Ct<20 fue significativamente mayor que la de casos con Cts>20. Las muestras con Cts<20 se asociaron a una carga viral estimada de entre 1 a 4 órdenes de magnitud de diferencia con los rangos de Ct >20. Un 13,7% de contactos estrechos positivos fueron de casos con Ct<20. Al estudiar muestras positivas con diagnóstico confirmado por PCR, correspondientes a la SE1 del 2021, sólo un 19,35% correspondían a muestras con Cts<20 y un 50,7% con Cts entre 20 y 30. A partir de estos datos se muestra que con el testeo de contactos estrechos podríamos detectar sólo un 3,7% de casos. El esfuerzo por parte del sistema de salud pública para esta estrategia, con bajo poder predictivo, puede tener un efecto negativo para el cumplimiento del aislamiento de los contactos y podría generar una demora en los resultados de los casos sospechosos, sin aportar significativamente a controlar la pandemia.
A detecção de SARS-CoV-2 e sua implicação no diagnóstico de COVID-19 têm sido altamente debatidos na pandemia. O acesso ao diagnóstico molecular e à sua população-alvo era parte essencial das políticas públicas. O objetivo deste estudo foi avaliar o custo / benefício da detecção da SARS-CoV-2 em contatos próximos assintomáticos usando diferentes testes de diagnóstico molecular. 51 contatos próximos de pessoas com diagnóstico de SARS-CoV-2 confirmado pelo RTqPCR, classificados pelo Ct (<20, entre 20 e 30 e> 30), foram estudados em hospitais públicos da Província de Buenos Aires. Do total de contatos estudados, 15,7% foram confirmados para SARS-CoV-2, não houve contato de casos com Ct> 30 positivo. O número de contatos positivos de casos com Ct <20 foi significativamente maior que o de casos com Ct> 20. As amostras com Cts <20 foram associadas a uma carga viral estimada de 1 a 4 ordens de diferença de magnitude com intervalos de Ct> 20. 13,7% dos contatos próximos positivos eram de casos com Ct <20. Ao estudar amostras positivas com diagnóstico confirmado por PCR, correspondentes a EW1 de 2021, apenas 19,35% corresponderam a amostras com Cts <20 e 50,7% com Cts entre 20 e 30. A partir desses dados, mostra-se que com o teste de contato próximo poderíamos detectar apenas 3,7% dos casos. O esforço do sistema público de saúde por essa estratégia, com baixo poder preditivo, pode repercutir negativamente no cumprimento do isolamento dos contatos e pode gerar atraso nos resultados dos casos suspeitos, sem contribuir significativamente para o controle da pandemia.
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Rac1 GTPase has long been recognized as a critical regulatory protein in different cellular and molecular processes involved in cancer progression, including acute myeloid leukemia. Here we show the antitumoral activity of ZINC69391 and 1A-116, two chemically-related Rac1 pharmacological inhibitors, on a panel of four leukemic cell lines representing different levels of maturation. Importantly, we show that the main mechanism involved in the antitumoral effect triggered by the Rac1 inhibitors comprises the induction of the mitochondrial or intrinsic apoptotic pathway. Interestingly, Rac1 inhibition selectively induced apoptosis on patient-derived leukemia cells but not on normal mononuclear cells. These results show the potential therapeutic benefits of targeting Rac1 pathway in hematopoietic malignancies.
