a b s t r a c tAn outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and its caused coronavirus disease 2019 has been reported in China since December 2019. More than 16% of patients developed acute respiratory distress syndrome, and the fatality ratio was about 1%-2%. No specific treatment has been reported. Herein, we examine the effects of Favipiravir (FPV) versus Lopinavir (LPV)/ritonavir (RTV) for the treatment of COVID-19. Patients with laboratory-confirmed COVID-19 who received oral FPV (Day 1: 1600 mg twice daily; Days 2-14: 600 mg twice daily) plus interferon (IFN)-a by aerosol inhalation (5 million U twice daily) were included in the FPV arm of this study, whereas patients who were treated with LPV/RTV (Days 1-14: 400 mg/100 mg twice daily) plus IFN-a by aerosol inhalation (5 million U twice daily) were included in the control arm. Changes in chest computed tomography (CT), viral clearance, and drug safety were compared between the two groups. For the 35 patients enrolled in the FPV arm and the 45 patients in the control arm, all baseline characteristics were comparable between the two arms. A shorter viral clearance time was found for the FPV arm versus the control arm (median (interquartile range, IQR), 4 (2.5-9) d versus 11 (8-13) d, P < 0.001). The FPV arm also showed significant improvement in chest imaging compared with the control arm, with an improvement rate of 91.43% versus 62.22% (P = 0.004). After adjustment for potential confounders, the FPV arm also showed a significantly higher improvement rate in chest imaging. Multivariable Cox regression showed that FPV was independently associated with faster viral clearance. In addition, fewer adverse reactions were found in the FPV arm than in the control arm. In this open-label nonrandomized control study, FPV showed significantly better treatment effects on COVID-19 in terms of disease progression and viral clearance; if causal, these results should be important information for establishing standard treatment guidelines to combat the SARS-CoV-2 infection.

Ras signaling plays an important role in erythropoiesis. Its function has been extensively studied in erythroid and nonerythroid cell lines as well as in primary erythroblasts, but inconclusive results using conventional erythroid colony-forming unit (CFU-E) assays have been obtained concerning the role of Ras signaling in erythroid differentiation. Here we describe a novel culture system that supports terminal fetal liver erythroblast proliferation and differentiation and that closely recapitulates erythroid development in vivo. Erythroid differentiation is monitored step by step and quantitatively by a flow cytometry analysis; this analysis distinguishes CD71 and TER119 doublestained erythroblasts into different stages of differentiation. To study the role of Ras signaling in erythroid differentiation, different H-ras proteins were expressed in CFU-E progenitors and early erythroblasts with the use of a bicistronic retroviral system, and their effects on CFU-E colony formation and erythroid differentiation were analyzed. Only oncogenic H-ras, not dominant-negative Hras, reduced CFU-E colony formation. Analysis of infected erythroblasts in our newly developed system showed that oncogenic H-ras blocks terminal erythroid differentiation, but not through promoting apoptosis of terminally differentiated erythroid cells. Rather, oncogenic H-ras promotes abnormal proliferation of CFU-E progenitors and early erythroblasts and supports their erythropoietin ( IntroductionWithin the fetal liver and the adult bone marrow, hematopoietic cells are formed continuously from a small population of pluripotent stem cells that generate progenitors committed to one or a few hematopoietic lineages. In the erythroid lineage, the earliest committed progenitors identified ex vivo are the slowly proliferating erythroid burst-forming units (BFU-Es). 1,2 These early BFU-E cells divide and further differentiate through the "mature" BFU-E stage into rapidly dividing erythroid colony-forming units (CFUEs). Neither of these 2 types of progenitors is identified by morphology but instead by the colonies they produce in colonyformation assays. BFU-E colonies take 15 days (human) or 7 to 10 days (mouse) to form in culture, whereas CFU-E colonies take 7 days (human) or 2 days (mouse). 1,2 CFU-E progenitors undergo 3 to 5 divisions as they differentiate through several morphologically defined stages: proerythroblasts, basophilic erythroblasts, polychromatophilic erythroblasts, and orthochromatophilic erythroblasts (OEs). Finally, the OEs extrude their nuclei (enucleation) and become reticulocytes, which further expel all organelles and detach from their microenvironment to form mature circulating erythrocytes. As erythroid differentiation proceeds, erythroblasts display a gradual decrease in cell size, increase in chromatin condensation, and increase in hemoglobin concentration. 3 Several cytokines and their receptors are important for erythroid differentiation. Among them, erythropoietin (Epo) and its specific receptor (EpoR) are crucial for pro...

The COVID-19 pandemic caused by the novel coronavirus SARS-CoV-2 has spread globally, with >52,000 cases in California as of May 4, 2020. Here we investigate the genomic epidemiology of SARS-CoV-2 in Northern California from late January to mid-March 2020, using samples from 36 patients spanning 9 counties and the Grand Princess cruise ship. Phylogenetic analyses revealed the cryptic introduction of at least 7 different SARS-CoV-2 lineages into California, including epidemic WA1 strains associated with Washington State, with lack of a predominant lineage and limited transmission between communities. Lineages associated with outbreak clusters in 2 counties were defined by a single base substitution in the viral genome. These findings support contact tracing, social distancing, and travel restrictions to contain SARS-CoV-2 spread in California and other states.

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