Background and Aims Chronic hepatitis B (CHB) and nonalcoholic fatty liver disease are increasingly observed together in clinical practice, and development of nonalcoholic steatohepatitis (NASH) represents another leading cause of liver‐related morbidity and mortality. Our aims were to determine whether biopsy‐proven NASH impacts clinical outcomes in CHB patients and assess prognostic risk factors. Approach and Results CHB patients attending two tertiary centers in North America and Europe over 13 years with available clinical and biopsy data were included. Patients were categorized as no‐NASH or probable/definite NASH based on standardized histological assessment. Clinical events (death, decompensation, transplant, and hepatoma) were evaluated, and Kaplan‐Meier survival estimates and Cox proportional hazards regression were used to analyze the incidence of events. There were 1,089 CHB patients, classified as no‐NASH (n = 904, 83%) or NASH (n = 185, 17%), with 52 (6%) versus 27 (15%) experiencing outcome events during follow‐up, respectively. In the multivariable analysis adjusting for age, sex, hepatitis B e antigen serostatus, and diabetes, the presence of NASH and concomitant advanced fibrosis (AF) was significantly associated with clinical outcomes (hazard ratio [95% confidence interval], 4.8 [2.6‐9.0], P < 0.01) when compared to absence of NASH and AF (reference). NASH and AF were associated with a greater risk of outcomes compared to AF (P = 0.01) or NASH alone (P < 0.01). Of the three histological determinants of NASH, ballooning and inflammation, but not steatosis, were independently associated with clinical outcomes (P < 0.05) in place of NASH. NASH was significantly associated with increased risk of hepatocellular carcinoma and death (P < 0.01) but not decompensation (P = 0.33). Conclusions In our large combined tertiary center cohort, patients with concomitant NASH and CHB had more AF and shorter time to development of liver‐related outcomes or death compared to patients with CHB alone. Among patients with AF, superimposed NASH predicted poorer clinical outcomes.

The dynamics of SARS-CoV-2 replication and shedding in humans remain poorly understood. We captured the dynamics of infectious virus and viral RNA shedding during acute infection through daily longitudinal sampling of 60 individuals for up to 14 days. By fitting mechanistic models, we directly estimated viral expansion and clearance rates, and overall infectiousness for each individual. Significant person-to-person variation in infectious virus shedding suggests that individual-level heterogeneity in viral dynamics contributes to superspreading. Viral genome loads often peaked days earlier in saliva than in nasal swabs, indicating strong tissue compartmentalization and suggesting that saliva may serve as a superior sampling site for early detection of infection. Viral loads and clearance kinetics of Alpha (B.1.1.7) and previously circulating non-variant of concern viruses were mostly indistinguishable, indicating that the enhanced transmissibility of this variant cannot be simply explained by higher viral loads or delayed clearance. These results provide a high-resolution portrait of SARS-CoV-2 infection dynamics and implicate individual-level heterogeneity in infectiousness in superspreading.

Background Serial screening is critical for restricting spread of SARS-CoV-2 by facilitating the timely identification of infected individuals to interrupt transmission chains. The variation in sensitivity of different diagnostic tests at different stages of infection has not been well documented. Methods This is a longitudinal study of 43 adults newly infected with SARS-CoV-2. All participants provided daily samples for saliva and nasal swab RTqPCR, Quidel SARS Sofia antigen FIA, and live virus culture. Results We show that both RTqPCR and the Quidel SARS Sofia antigen FIA peak in sensitivity during the period in which live virus is detected in nasal swabs, but the sensitivity of RTqPCR tests rises more rapidly prior to this period. We also estimate the sensitivities of RTqPCR and antigen tests as a function of testing frequency. Conclusions RTqPCR tests are more effective than antigen tests at identifying infected individuals prior to or early during the infectious period and thus for minimizing forward transmission (given timely results reporting). All tests showed &gt;98% sensitivity for identifying infected individuals if used at least every three days. Daily screening using antigen tests can achieve ~90% sensitivity for identifying infected individuals while they are viral culture positive.

Genome editing of human induced pluripotent stem cells (iPSCs) is instrumental for functional genomics, disease modeling, and regenerative medicine. However, low editing efficiency has hampered the applications of CRISPR–Cas9 technology in creating knockin (KI) or knockout (KO) iPSC lines, which is largely due to massive cell death after electroporation with editing plasmids. Here, we report that the transient delivery of BCL-XL increases iPSC survival by ∼10-fold after plasmid transfection, leading to a 20- to 100-fold increase in homology-directed repair (HDR) KI efficiency and a 5-fold increase in non-homologous end joining (NHEJ) KO efficiency. Treatment with a BCL inhibitor ABT-263 further improves HDR efficiency by 70% and KO efficiency by 40%. The increased genome editing efficiency is attributed to higher expressions of Cas9 and sgRNA in surviving cells after electroporation. HDR or NHEJ efficiency reaches 95% with dual editing followed by selection of cells with HDR insertion of a selective gene. Moreover, KO efficiency of 100% can be achieved in a bulk population of cells with biallelic HDR KO followed by double selection, abrogating the necessity for single cell cloning. Taken together, these simple yet highly efficient editing strategies provide useful tools for applications ranging from manipulating human iPSC genomes to creating gene-modified animal models.

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Single-cell RNA sequencing (scRNA-seq) has become a very powerful technology for biomedical research and is becoming much more affordable as methods continue to evolve, but it is unknown how reproducible different platforms are using different bioinformatics pipelines, particularly the recently developed scRNA-seq batch correction algorithms. We carried out a comprehensive .

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Metabolic dysfunction-associated fatty liver disease increases risk of adverse outcomes in patients with chronic hepatitis B