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In Drosophila, post-transcriptional gene silencing occurs when exogenous or endogenous double stranded RNA (dsRNA) is processed into small interfering RNAs (siRNAs) by Dicer-2 (Dcr-2) in association with a dsRNA-binding protein (dsRBP) cofactor called Loquacious (Loqs-PD). siRNAs are then loaded onto Argonaute-2 (Ago2) by the action of Dcr-2 with another dsRBP cofactor called R2D2. Loaded Ago2 executes the destruction of target RNAs that have sequence complementarity to siRNAs. Although Dcr-2, R2D2, and Ago2 are essential for innate antiviral defense, the mechanism of virus-derived siRNA (vsiRNA) biogenesis and viral target inhibition remains unclear. Here, we characterize the response mechanism mediated by siRNAs against two different RNA viruses that infect Drosophila. In both cases, we show that vsiRNAs are generated by Dcr-2 processing of dsRNA formed during viral genome replication and, to a lesser extent, viral transcription. These vsiRNAs seem to preferentially target viral polyadenylated RNA to inhibit viral replication. Loqs-PD is completely dispensable for silencing of the viruses, in contrast to its role in silencing endogenous targets. Biogenesis of vsiRNAs is independent of both Loqs-PD and R2D2. R2D2, however, is required for sorting and loading of vsiRNAs onto Ago2 and inhibition of viral RNA expression. Direct injection of viral RNA into Drosophila results in replication that is also independent of Loqs-PD. This suggests that triggering of the antiviral pathway is not related to viral mode of entry but recognition of intrinsic features of virus RNA. Our results indicate the existence of a vsiRNA pathway that is separate from the endogenous siRNA pathway and is specifically triggered by virus RNA. We speculate that this unique framework might be necessary for a prompt and efficient antiviral response.

Background: Large language models such as ChatGPT can produce increasingly realistic text, with unknown information on the accuracy and integrity of using these models in scientific writing. Methods: We gathered ten research abstracts from five high impact factor medical journals (n=50) and asked ChatGPT to generate research abstracts based on their titles and journals. We evaluated the abstracts using an artificial intelligence (AI) output detector, plagiarism detector, and had blinded human reviewers try to distinguish whether abstracts were original or generated. Results: All ChatGPT-generated abstracts were written clearly but only 8% correctly followed the specific journal's formatting requirements. Most generated abstracts were detected using the AI output detector, with scores (higher meaning more likely to be generated) of median [interquartile range] of 99.98% [12.73, 99.98] compared with very low probability of AI-generated output in the original abstracts of 0.02% [0.02, 0.09]. The AUROC of the AI output detector was 0.94. Generated abstracts scored very high on originality using the plagiarism detector (100% [100, 100] originality). Generated abstracts had a similar patient cohort size as original abstracts, though the exact numbers were fabricated. When given a mixture of original and general abstracts, blinded human reviewers correctly identified 68% of generated abstracts as being generated by ChatGPT, but incorrectly identified 14% of original abstracts as being generated. Reviewers indicated that it was surprisingly difficult to differentiate between the two, but that the generated abstracts were vaguer and had a formulaic feel to the writing. Conclusion: ChatGPT writes believable scientific abstracts, though with completely generated data. These are original without any plagiarism detected but are often identifiable using an AI output detector and skeptical human reviewers. Abstract evaluation for journals and medical conferences must adapt policy and practice to maintain rigorous scientific standards; we suggest inclusion of AI output detectors in the editorial process and clear disclosure if these technologies are used. The boundaries of ethical and acceptable use of large language models to help scientific writing remain to be determined.

Rationale: Current guidelines recommend patients with SARS-CoV-2 pneumonia receive empirical antibiotics for suspected bacterial superinfection based on weak evidence. Rates of ventilator-associated pneumonia (VAP) in clinical trials of patients with SARS-CoV-2 pneumonia are unexpectedly low. Objectives: We conducted an observational single center study to determine the prevalence and etiology of bacterial superinfection at the time of initial intubation and the incidence and etiology of subsequent bacterial VAP in patients with severe SARS-CoV-2 pneumonia. Methods: Bronchoscopic bronchoalveolar lavage (BAL) fluid samples from all patients with SARS-CoV-2 pneumonia requiring mechanical ventilation were analyzed using quantitative cultures and a multiplex polymerase chain reaction panel. Actual antibiotic use was compared with guideline-recommended therapy. Measurements and Main Results: We analyzed 386 BAL samples from 179 patients with SARS-CoV-2 pneumonia requiring mechanical ventilation. Bacterial superinfection within 48 hours of intubation was detected in 21% of patients. 72 patients (44.4%) developed at least one VAP episode (VAP incidence rate 45.2/1000 ventilator days); 15 (20.8%) of initial VAPs were caused by difficult-to-treat pathogens. Clinical criteria did not distinguish between patients with or without bacterial superinfection. BAL-based management was associated with significantly reduced antibiotic use compared with guideline recommendations. Conclusions: In patients with SARS-CoV-2 pneumonia requiring mechanical ventilation, bacterial superinfection at the time of intubation occurs in less than 25% of patients. Guidelinebased empirical antibiotic management at the time of intubation results in antibiotic overuse.

Background Veno‐venous extracorporeal membrane oxygenation (V‐V ECMO) support is increasingly used in the management of COVID‐19‐related acute respiratory distress syndrome (ARDS). However, the clinical decision‐making to initiate V‐V ECMO for severe COVID‐19 still remains unclear. In order to determine the optimal timing and patient selection, we investigated the outcomes of both COVID‐19 and non‐COVID‐19 patients undergoing V‐V ECMO support. Methods Overall, 138 patients were included in this study. Patients were stratified into two cohorts: those with COVID‐19 and non‐COVID‐19 ARDS. Results The survival in patients with COVID‐19 was statistically similar to non‐COVID‐19 patients ( p = .16). However, the COVID‐19 group demonstrated higher rates of bleeding ( p = .03) and thrombotic complications ( p < .001). The duration of V‐V ECMO support was longer in COVID‐19 patients compared to non‐COVID‐19 patients (29.0 ± 27.5 vs 15.9 ± 19.6 days, p < .01). Most notably, in contrast to the non‐COVID‐19 group, we found that COVID‐19 patients who had been on a ventilator for longer than 7 days prior to ECMO had 100% mortality without a lung transplant. Conclusions These findings suggest that COVID‐19‐associated ARDS was not associated with a higher post‐ECMO mortality than non‐COVID‐19‐associated ARDS patients, despite longer duration of extracorporeal support. Early initiation of V‐V ECMO is important for improved ECMO outcomes in COVID‐19 ARDS patients. Since late initiation of ECMO was associated with extremely high mortality related to lack of pulmonary recovery, it should be used judiciously or as a bridge to lung transplantation.

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Our aim was to construct and characterize 111 In-nuclear translocation sequence (NLS)-7G3, an Auger electron-emitting radioimmunotherapeutic agent that preferentially recognizes the expression of CD123 (interleukin-3 receptor [IL-3R] a-subchain) in the absence of CD131 (IL-3R b-subchain) displayed by leukemia stem cells. Methods: Monoclonal antibody 7G3 was modified with 13-mer peptides [CGYGPKKKRKVGG] harboring the NLS of SV-40 large T-antigen and with diethylenetriaminepentaacetic acid for labeling with 111 In. Immunoreactivity was evaluated in a competition radioligand binding assay and by flow cytometry. Nuclear localization of 111 In-NLS-7G3 was studied by cell fractionation in CD123 1 /CD131 2 acute myelogenous leukemia (AML)-3, -4, and -5 cells or in primary AML or normal leukocytes. Micro-SPECT was performed in nonobese diabetic (NOD)/severe combined immune deficient (SCID) mice engrafted subcutaneously with Raji-CD123 tumors or with disseminated AML-3 or -5 cells. The cytotoxicity of 111 In-NLS-7G3 on AML-5 cells was studied after 7 d in culture by trypan blue dye exclusion. DNA damage was assessed using the g-H2AX assay. Results: NLS-7G3 exhibited preserved CD123 immunoreactivity (affinity, 4.6 nmol/L). Nuclear importation of 111 In-NLS-7G3 in AML-3, -4, or -5 cells was specific and significantly higher than unmodified 111 In-7G3 and was greater in primary AML cells than in normal leukocytes. Rapid elimination of 111 In-NLS-7G3 in NOD/SCID mice prevented imaging of subcutaneous Raji-CD123 tumors. This phenomenon was Fc-dependent and IgG 2a isotype-specific and was overcome by the preadministration of excess IgG 2a or using 111 In-NLS-7G3 F(ab9) 2 fragments. AML-3 and -5 cells were engrafted into the bone marrow or spleen or at extramedullary sites in NOD/SCID mice. Micro-SPECT/CT with 111 In-NLS-7G3 F(ab9) 2 showed splenic involvement, whereas foci of disease were seen in the spine or femur or at extramedullary sites in the brain and lymph nodes using 111 In-NLS-7G3 IgG 2a . The viability of AML-5 cells was reduced by exposure in vitro to 111 In-NLS-7G3; this reduction was associated with an increase in unrepaired DNA double-strand breaks. Conclusion: 111 In-NLS-7G3 is a promising novel Auger electron-emitting radioimmunotherapeutic agent for AML aimed at the leukemia stem cell population. Micro-SPECT/CT was useful for visualizing the engraftment of leukemia in NOD/SCID mice.

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