Viral shedding dynamics reveals sputum as a reliable and cost-saving specimen for SARS-CoV-2 diagnosis within the first 10 days since symptom onset: A prospective cohort study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome virus (SARS-CoV-2) is challenging global public health, due to an increasing demand for testing and the shortage of diagnostic supplies. Nasopharyngeal swab (NPS) is considered the optimal sample for SARS-CoV2 diagnosis and sputum (SPT) has been proposed as an economic alternative. However, the temporal concordance of diagnosis in NPS and SPT has not been addressed. METHODS: Through a longitudinal study we compared the shedding dynamics of SARS-CoV-2 RNA evaluated by RT-qPCR in serially collected SPT and NPS obtained from 82 ambulatory and hospitalized patients during acute infection and convalescence. The concordance during the follow-up and cost analysis between both collected specimens was evaluated. FINDINGS: We analyzed 379 samples, 177 NPS and 202 SPT. The highest proportion of positive samples was detected within the first 15 days after the symptoms onset. The median time of positivity was higher for NPS (median= 25 days) than SPT (median= 21 days). There was no significant difference in the median RT-qPCR CT values between both sample types. The temporal categorization of matched-paired samples indicated substantial correlation (r=0.6023) and substantial agreement (87.23%) during the first ten days since symptoms onset (kappa = 0.697). A cost analysis demonstrated a significant saving when the SPT specimen was used. INTERPRETATION: Sputum is a feasible and cost-saving alternative to NPS, providing an equivalent value for the detection and follow-up of SARS-CoV-2 RNA.

Salmon cells SHK-1 internalize infectious pancreatic necrosis virus by macropinocytosis.

We have previously shown that infectious pancreatic necrosis virus (IPNV) enters the embryo cell line CHSE-214 by macropinocytosis. In this study, we have extended our investigation into SHK-1 cells, a macrophage-like cell line derived from the head kidney of Atlantic salmon, the most economically important host of IPNV. We show that IPNV infection stimulated fluid uptake in SHK-1 cells above the constitutive macropinocytosis level. In addition, upon infection of SHK-1 cells, IPNV produced several changes in actin dynamics, such as protrusions and ruffles, which are important features of macropinocytosis. We also observed that the Na+/H+ pump inhibitor EIPA blocked IPNV infection. On the other hand, IPNV entry was independent of clathrin, a possibility that could not be ruled out in CHSE 214 cells. In order to determine the possible role of accessory factors on the macropinocytic process, we tested several inhibitors that affect components of transduction pathways. While pharmacological intervention of PKI3, PAK-1 and Rac1 did not affect IPNV infection, inhibition of Ras and Rho GTPases as well as Cdc42 resulted in a partial decrease in IPNV infection. Further studies will be required to determine the signalling pathway involved in the macropinocytosis-mediated entry of IPNV into its target cells.

Variabilidad en la determinación del estado de HER2 por inmunohistoquímica en Chile / The Chilean experience of variability in the assessment of HER2 status using immunohistochemistry

Introducción: La determinación del estado del gen HER2 en el cáncer de mama es un marcador pronóstico, predictivo y de decisión terapéutica que requiere ser realizado con una técnica exacta. Objetivo: Evaluar la variabilidad de la determinación del estado del HER2 por técnica inmunohistoquímica (IHQ) en laboratorios chilenos. Pacientes y métodos: Se analizaron 221 biopsias con cáncer de mama invasivo provenientes de 41 laboratorios nacionales para determinar el estado del HER2 por hibridación in situ fluorescente (FISH). Un total de 201 biopsias permitieron análisis. El estado del HER2 se determinó por IHQ y FISH en forma estandarizada de acuerdo con las recomendaciones de la American Society of Clinical Oncology y el College of American Pathologists. Estos resultados fueron comparados con los informes de IHQ provenientes de los diferentes laboratorios. Resultados: La variabilidad de la evaluación del estado de HER2 en laboratorios nacionales es similar a lo descrito en la literatura internacional: llega al 19,7% cuando se compara con una técnica IHQ estandarizada y alcanza el 26,9% cuando se compara con FISH. La tasa de falsos positivos en IHQ es del 15,7 y del 25,6% comparados con FISH. Conclusiones: Este estudio confirma la necesidad de que los laboratorios chilenos que realicen la determinación del estado del HER2 cuenten con una técnica IHQ validada con estrictos controles de calidad interno y externo, y que empleen procedimientos técnicos y de interpretación estandarizados según recomendaciones internacionales para una correcta decisión terapéutica(AU)

Background: HER2 gene status in breast cancer is an important prognostic marker and therefore must be assessed using an accurate technique. Objective: To assess the variability in the evaluation of HER2 status using immunohistochemistry (IHC) in Chilean laboratories. Patients and methods: We analyzed 221 biopsies of invasive breast cancer from 41 laboratories nationwide, assessing HER2 status by Fluorescent In Situ Hybridization (FISH). Analysis was possible in 201of the biopsies. The HER2 status was determined by IHC and FISH in a standardized way in accordance with the recommendations of the American Society of Clinical Oncology and the College of American Pathologists (ASCO/CAP). The results were compared with IHC reports from different laboratories. Results: The variability of the assessment of HER2 status in the 41 laboratories is similar to that reported in the literature. In comparison with standardized IHC technique, variability was 19.7% but reached 25.9% when compared to FISH. The rate of false positives in IHC is 15.7% and 25.6% when compared to FISH. Conclusions: This study confirms that, in order to make the correct therapeutic decision, the IHC technique used in the assessment of HER2 status should undergo stringent internal and external quality controls. Technical and interpretative procedures should be standardized according to international recommendations(AU)