Rational protein engineering to enhance MHC-independent T cell receptors.

Chimeric antigen receptor (CAR)-based therapies have pioneered synthetic cellular immunity but remain limited in their long-term efficacy. Emerging data suggest that dysregulated CAR-driven T cell activation causes T cell dysfunction and therapeutic failure. To re-engage the precision of the endogenous T cell response, we designed MHC-independent T cell receptors (miTCRs) by linking antibody variable domains to TCR constant chains. Using predictive modeling, we observed that this standard "cut and paste" approach to synthetic protein design resulted in myriad biochemical conflicts at the hybrid variable-constant domain interface. Through iterative modeling and sequence modifications we developed structure-enhanced miTCRs which significantly improved receptor-driven T cell function across multiple tumor models. We found that 41BB costimulation specifically prolonged miTCR T cell persistence and enabled improved leukemic control in vivo compared to classic CAR T cells. Collectively, we have identified core features of hybrid receptor structure responsible for regulating function.

Hepatic artery infusion pump (HAIP) therapy in combination with targeted delivery of IL-12 for patients with metastatic colorectal cancer or intrahepatic cholangiocarcinoma: a phase II trial protocol.

Background: Treatment of advanced liver tumors remains challenging. Although immune checkpoint inhibition has revolutionized treatment for many cancers, responses in colorectal liver metastases and biliary tract cancers remain suboptimal. Investigation into additional immunomodulatory therapies for these cancers is needed. Interleukin-12 (IL-12) is a pro-inflammatory cytokine with robust anti-tumor activity, but systemic adverse effects largely terminated therapeutic development of recombinant human IL-12 (rhIL-12). PDS01ADC is a novel human monoclonal antibody (NHS76) conjugated to two IL-12 heterodimers with established safety in phase I trials. The NHS76 antibody specifically targets histone/DNA complexes which are accessible only in regions of cell death and this antibody has been shown to accumulate locally in tumors. Methods: Patients with unresectable metastatic colorectal cancer (mCRC) or unresectable intrahepatic cholangiocarcinoma (ICC) will receive synchronization of subcutaneous PDS01ADC with floxuridine delivered via a hepatic artery infusion pump (HAIP). The primary outcome measured in this study will be overall response rate as measured by Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Secondary outcomes measured in this study will include hepatic and non-hepatic progression-free survival (PFS), overall survival, and safety of PDS01ADC combination therapy with HAIP. Discussion: Poor clinical response of these liver tumors to immunotherapy is likely due to various factors, including poor immune infiltrate into the tumor and immunosuppression by the tumor microenvironment. By exploiting the tumor cell death induced by HAIP locoregional therapy in combination with systemic chemotherapy, PDS01ADC is poised to modulate the tumor immune microenvironment to improve outcomes for patients undergoing HAIP therapy. Trial Registration: ClinicalTrials.gov (ID NCT05286814 version 2023-10-18); https://clinicaltrials.gov/study/NCT05286814?term=NCT05286814&rank=1.

Progressive Choriocapillaris Changes on Optical Coherence Tomography Angiography Correlate With Stage Progression in AMD.

Purpose: We investigated the association between inner choroid flow deficit percentage (IC-FD%) using swept-source optical coherence tomography angiography (SS-OCTA) and progression of AMD. Methods: Retrospective, observational study including 64 eyes (42 participants) with early or intermediate AMD at baseline. Participants had two or more consecutive swept-source optical coherence tomography angiography covering a period of at least 18 months. Demographics, visual acuity, and AMD staging based on Beckman classification were reviewed. OCT was analyzed for hyperreflective foci, subretinal drusenoid deposits, hyporeflective drusen cores, and subfoveal choroidal thickness. IC-FD% was measured within the central 3- and 6-mm using a 16-µm slab, after compensation and binarization (Phansalkar method). Mixed-effects Cox regression models assessed the association between imaging biomarkers and AMD progression. Results: During follow-up (37 ± 9 months), 4 eyes with early AMD (31%) progressed to intermediate AMD and 30 (59%) eyes with intermediate AMD developed late AMD (19 geographic atrophy; 11 wet AMD). Baseline hyporeflective drusen core was associated with geographic atrophy development (P < 0.01), whereas greater IC-FD% (3-mm) was associated with wet AMD (P = 0.03). Time-varying analysis showed that faster subfoveal choroidal thickness reduction and IC-FD% (6-mm) increase were associated with geographic atrophy onset (P < 0.05), whereas IC-FD% (3-mm) increase was associated with wet AMD (P = 0.03). Notably, greater IC-FD% increases in the 3 mm (area under the curve = 0.72) and 6 mm (area under the curve = 0.89) were better predictive of wet AMD and geographic atrophy development, respectively. Conclusions: Our longitudinal IC-FD% assessment emphasizes the role of progressive choriocapillaris changes as a biomarker for AMD progression. Our findings support that widespread choriocapillaris alterations (6 mm) may precede progression to geographic atrophy, whereas more central choriocapillaris loss (3 mm) may provide an ischemic stimulus for wet AMD.

RNA-sequencing reveals differential fibroblast responses to bleomycin and pneumonectomy.

Pulmonary fibrosis is characterized by pathological accumulation of scar tissue in the lung parenchyma. Many of the processes that are implicated in fibrosis, including increased extracellular matrix synthesis, also occur following pneumonectomy (PNX), but PNX instead results in regenerative compensatory growth of the lung. As fibroblasts are the major cell type responsible for extracellular matrix production, we hypothesized that comparing fibroblast responses to PNX and bleomycin (BLM) would unveil key differences in the role they play during regenerative versus fibrotic lung responses. RNA-sequencing was performed on flow-sorted fibroblasts freshly isolated from mouse lungs 14 days after BLM, PNX, or sham controls. RNA-sequencing analysis revealed highly similar biological processes to be involved in fibroblast responses to both BLM and PNX, including TGF-ß1 and TNF-α. Interestingly, we observed smaller changes in gene expression after PNX than BLM at Day 14, suggesting that the fibroblast response to PNX may be muted by expression of transcripts that moderate pro-fibrotic pathways. Itpkc, encoding inositol triphosphate kinase C, was a gene uniquely up-regulated by PNX and not BLM. ITPKC overexpression in lung fibroblasts antagonized the pro-fibrotic effect of TGF-ß1. RNA-sequencing analysis has identified considerable overlap in transcriptional changes between fibroblasts following PNX and those overexpressing ITPKC.

Deeper and stronger North Atlantic Gyre during the Last Glacial Maximum.

Subtropical gyre (STG) depth and strength are controlled by wind stress curl and surface buoyancy forcing1,2. Modern hydrographic data reveal that the STG extends to a depth of about 1 km in the Northwest Atlantic, with its maximum depth defined by the base of the subtropical thermocline. Despite the likelihood of greater wind stress curl and surface buoyancy loss during the Last Glacial Maximum (LGM)3, previous work suggests minimal change in the depth of the glacial STG4. Here we show a sharp glacial water mass boundary between 33° N and 36° N extending down to between 2.0 and 2.5 km-approximately 1 km deeper than today. Our findings arise from benthic foraminiferal δ18O profiles from sediment cores in two depth transects at Cape Hatteras (36-39° N) and Blake Outer Ridge (29-34° N) in the Northwest Atlantic. This result suggests that the STG, including the Gulf Stream, was deeper and stronger during the LGM than at present, which we attribute to increased glacial wind stress curl, as supported by climate model simulations, as well as greater glacial production of denser subtropical mode waters (STMWs). Our data suggest (1) that subtropical waters probably contributed to the geochemical signature of what is conventionally identified as Glacial North Atlantic Intermediate Water (GNAIW)5-7 and (2) the STG helped sustain continued buoyancy loss, water mass conversion and northwards meridional heat transport (MHT) in the glacial North Atlantic.

Targeting CEBPA to restore cellular identity and tissue homeostasis in pulmonary fibrosis.

Fibrosis in the lung is thought to be driven by epithelial cell dysfunction and aberrant cell-cell interactions. Unveiling the molecular mechanisms of cellular plasticity and cell-cell interactions is imperative to elucidate lung regenerative capacity and aberrant repair in pulmonary fibrosis. By mining publicly available RNA-seq datasets, we identified loss of CCAAT enhancer-binding protein alpha (CEBPA) as a candidate contributor to idiopathic pulmonary fibrosis (IPF). We used conditional knockout mice, scRNA-seq, lung organoids, small-molecule inhibition and novel gene manipulation methods to investigate the role of CEBPA in lung fibrosis and repair. Long term (6 month+) of Cebpa loss in AT2 cells caused spontaneous fibrosis and increased susceptibility to bleomycin-induced fibrosis. Cebpa knockout in these mice significantly decreased AT2 cell numbers in the lung and reduced expression of surfactant homeostasis genes, while increasing inflammatory cell recruitment as well as upregulating S100a8/a9 in AT2 cells. In vivo treatment with an S100A8/A9 inhibitor alleviated experimental lung fibrosis. Restoring CEBPA expression in lung organoids ex vivo and during experimental lung fibrosis in vivo rescued CEBPA deficiency-mediated phenotypes. Our study establishes a direct mechanistic link between CEBPA repression, impaired AT2 cell identity, disrupted tissue homeostasis, and lung fibrosis.

Shiga toxin-producing Escherichia coli O157:H7 outbreak associated with school field trips at a farm animal exhibit-Tennessee, September-October 2023.

AIMS: In October 2023, the Tennessee Department of Health identified an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157:H7 infections among elementary school students who attended school field trips to the same farm animal exhibit. Our aim was to determine STEC source and prevent additional illnesses by initiating epidemiologic, laboratory and environmental investigations. METHODS AND RESULTS: We identified cases using laboratory-based surveillance and by surveying caregivers of children who attended the exhibit. Probable cases were defined as illness with abdominal cramps or diarrhoea after attendance; confirmed cases were laboratory-confirmed STEC infection in an attendee or household contact. A site visit was conducted, and event organizers were interviewed. Human stool, animal faeces and environmental samples were tested for STEC O157:H7 by real-time polymerase chain reaction (PCR), culture and whole-genome sequencing (WGS). Approximately 2300 elementary school students attended the animal exhibit during 2 days. Field trip activities included contact with different farm animal species, drinking pasteurized milk outside animal enclosures and eating lunch in a separate building onsite. We received survey responses from 399 caregivers for 443 (19%) animal exhibit attendees. We identified 9 confirmed and 55 probable cases with illness onset dates during 26 September to 12 October. Seven children aged 1-7 years were hospitalized. Four children aged 1-6 years experienced haemolytic uraemic syndrome; none died. Laboratory testing identified STEC O157:H7 by culture from eight human stool samples with 0-1 allele difference by WGS. Three environmental samples had Shiga toxin (stx 2) genes detected by PCR, but no STEC isolates were recovered by culture. CONCLUSIONS: This is the largest reported STEC O157:H7 outbreak associated with an animal exhibit in Tennessee. We identified opportunities for educating school staff, event organizers and families about zoonotic disease risks associated with animal contact and published prevention measures.

Identification of core techniques that enhance genome editing of human T cells expressing synthetic antigen receptors.

Genome editing technologies have seen remarkable progress in recent years, enabling precise regulation of exogenous and endogenous genes. These advances have been extensively applied to the engineering of human T lymphocytes, leading to the development of practice changing therapies for patients with cancer and the promise of synthetic immune cell therapies for a variety of non-malignant diseases. Many distinct conceptual and technical approaches have been used to edit T-cell genomes, however targeted assessments of which techniques are most effective for manufacturing, gene editing and transgene expression are rarely reported. Through extensive comparative evaluation, we identified methods that most effectively enhance engineering of research-scale and pre-clinical T-cell products at critical stages of manufacturing.

Decreased Macular Choriocapillaris Perfusion Correlates with Contrast Sensitivity Function in Dry Age-related Macular Degeneration.

PURPOSE: To investigate the relationships between contrast sensitivity (CS), choriocapillaris perfusion and other structural optical coherence tomography (OCT) biomarkers in dry age-related macular degeneration (AMD). DESIGN: Cross-sectional, observational study. PARTICIPANTS: One hundred AMD eyes (22 early, 52 intermediate and 26 late) from 74 patients and 45 control eyes from 37 age-similar subjects. METHODS: All participants had visual acuity (VA) assessment, quantitative contrast sensitivity function (qCSF) testing, macular OCT, and 6x6-mm swept-source OCT angiography (OCTA) scans on the same day. OCT volumes were analyzed for subretinal drusenoid deposits and hyporeflective drusen cores, and to measure thickness of the outer nuclear layer (ONL). OCTA scans were utilized to calculate drusen volume, inner choroid flow deficit percentage (IC-FD%), and to measure the area of choroidal hypertransmission defects (HTD). IC-FD% was measured from a 16 µm-thick choriocapillaris slab after compensation and binarization with Phansalkar's method. Generalized linear mixed-effects models were used to evaluate the associations between functional and structural variables. MAIN OUTCOME MEASURES: To explore the associations between qCSF-measured CS, ICFD% and various AMD imaging biomarkers. RESULTS: AMD exhibited significantly reduced qCSF metrics eyes across all stages compared to controls. Univariate analysis revealed significant associations between various imaging biomarkers, reduced qCSF metrics and VA in both groups. Multivariate analysis confirmed that higher IC-FD% in the central 5 mm was significantly associated with decreases in all qCSF metrics in AMD eyes (ß= -0.74 to -0.25, all p<0.05), but not with VA (p>0.05). ONL thickness in the central 3 mm correlated with both VA (ß= 2.85, p<0.001) and several qCSF metrics (ß= 0.01-0.90, all p<0.05), especially in AMD eyes. Further, larger HTD areas were associated with decreased VA (ß=-0.89, p<0.001) and reduced CS at low-intermediate frequencies across AMD stages (ß= -0.30 to -0.29, p<0.001). CONCLUSIONS: The significant association between IC-FD% in the central 5 mm and qCSF-measured CS reinforces the hypothesis that decreased macular choriocapillaris perfusion contributes to visual function changes in AMD, which are more pronounced in CS than in VA.

The peak viscosity of decaying foam with natural drainage and coarsening.

Studying the change in foam viscosity during foam decay, a spontaneous and inevitable process, is of fundamental and practical interest across many applications, ranging from the froth in a cup of coffee to the carbon sequestration in deep geological reservoirs. However, standard rheological measurements impose several experimental constraints, such as the narrow sample confinement and the long initial setup time, interfering with the natural conditions for foam decay. Here, we perform fast and in situ measurements on decaying foam immediately after its generation in a wide column, measuring the viscosity by vibrational probes and measuring the foam structure by optical imaging. We successfully capture the changes during the transition from the drainage-dominated stage to the coarsening-dominated stage. The viscosity reaches its maximum at the crossover point, elucidating the competing effects of drainage and coarsening. The viscosity peaks magnitude and position are influenced by the gas solubility and diffusion coefficient. The phenomena are quantitatively explained by the film-shearing model. Our findings provide the foundation for enhancing foam stability and performance, improving the efficiency of foam-based applications.

Novel requirements for HAP2/GCS1-mediated gamete fusion in Tetrahymena.

The ancestral gamete fusion protein, HAP2/GCS1, plays an essential role in fertilization in a broad range of taxa. To identify factors that may regulate HAP2/GCS1 activity, we screened mutants of the ciliate Tetrahymena thermophila for behaviors that mimic Δhap2/gcs1 knockout phenotypes in this species. Using this approach, we identified two new genes, GFU1 and GFU2, whose products are necessary for membrane pore formation following mating type recognition and adherence. GFU2 is predicted to be a single-pass transmembrane protein, while GFU1, though lacking obvious transmembrane domains, has the potential to interact directly with membrane phospholipids in the cytoplasm. Like Tetrahymena HAP2/GCS1, expression of GFU1 is required in both cells of a mating pair for efficient fusion to occur. To explain these bilateral requirements, we propose a model that invokes cooperativity between the fusion machinery on apposed membranes of mating cells and accounts for successful fertilization in Tetrahymena's multiple mating type system.

Spatial Single-cell Analysis Decodes Cortical Layer and Area Specification.

The human cerebral cortex, pivotal for advanced cognitive functions, is composed of six distinct layers and dozens of functionally specialized areas1,2. The layers and areas are distinguished both molecularly, by diverse neuronal and glial cell subtypes, and structurally, through intricate spatial organization3,4. While single-cell transcriptomics studies have advanced molecular characterization of human cortical development, a critical gap exists due to the loss of spatial context during cell dissociation5,6,7,8. Here, we utilized multiplexed error-robust fluorescence in situ hybridization (MERFISH)9, augmented with deep-learning-based cell segmentation, to examine the molecular, cellular, and cytoarchitectural development of human fetal cortex with spatially resolved single-cell resolution. Our extensive spatial atlas, encompassing 16 million single cells, spans eight cortical areas across four time points in the second and third trimesters. We uncovered an early establishment of the six-layer structure, identifiable in the laminar distribution of excitatory neuronal subtypes by mid-gestation, long before the emergence of cytoarchitectural layers. Notably, while anterior-posterior gradients of neuronal subtypes were generally observed in most cortical areas, a striking exception was the sharp molecular border between primary (V1) and secondary visual cortices (V2) at gestational week 20. Here we discovered an abrupt binary shift in neuronal subtype specification at the earliest stages, challenging the notion that continuous morphogen gradients dictate mid-gestation cortical arealization6,10. Moreover, integrating single-nuclei RNA-sequencing and in situ whole transcriptomics revealed an early upregulation of synaptogenesis in V1-specific Layer 4 neurons, suggesting a role of synaptogenesis in this discrete border formation. Collectively, our findings underscore the crucial role of spatial relationships in determining the molecular specification of cortical layers and areas. This work not only provides a valuable resource for the field, but also establishes a spatially resolved single-cell analysis paradigm that paves the way for a comprehensive developmental atlas of the human brain.

An analysis of double-quantum coherence ESR in an N-spin system: Analytical expressions and predictions.

Electron spin resonance pulsed dipolar spectroscopy (PDS) has become popular in protein 3D structure analysis. PDS studies yield distance distributions between a pair or multiple pairs of spin probes attached to protein molecules, which can be used directly in structural studies or as constraints in theoretical predictions. Double-quantum coherence (DQC) is a highly sensitive and accurate PDS technique to study protein structures in the solid state and under physiologically relevant conditions. In this work, we have derived analytical expressions for the DQC signal for a system with N-dipolar coupled spin-1/2 particles in the solid state. The expressions are integrated over the relevant spatial parameters to obtain closed form DQC signal expressions. These expressions contain the concentration-dependent "instantaneous diffusion" and the background signal. For micromolar and lower concentrations, these effects are negligible. An approximate analysis is provided for cases of finite pulses. The expressions obtained in this work should improve the analysis of DQC experimental data significantly, and the analytical approach could be extended easily to a wide range of magnetic resonance phenomena.

"Hang Ups, Let Downs, Bad Breaks, Setbacks": Impact of Structural Socioeconomic Racism and Resilience on Cognitive Change Over Time for Persons Racialized as Black.

Introduction: Older adults racialized as Black experience higher rates of dementia than those racialized as White. Structural racism produces socioeconomic challenges, described by artist Marvin Gaye as "hang ups, let downs, bad breaks, setbacks" that likely contribute to dementia disparities. Robust dementia literature suggests socioeconomic factors may also be key resiliencies. Methods: We linked state-level data reflecting the racialized landscape of economic opportunity across the 20th Century from the U.S. Census (1930-2010) with individual-level data on cognitive outcomes from the U.S. Health and Retirement Study participants racialized as Black. A purposive sample of participants born after the Brown v. Board ruling (born 1954-59) were selected who completed the modified Telephone Interview for Cognitive Status between 2010 and 2020 (N=1381). We tested associations of exposure to structural racism and resilience before birth, and during childhood, young-adulthood, and midlife with cognitive trajectories in mid-late life using mixed-effects regression models. Results: Older adults born in places with higher state-level structural socioeconomic racism experienced a more rapid cognitive decline in later life compared to those with lower levels of exposure. In addition, participants born in places with higher levels of state-level structural socioeconomic resilience experienced slower cognitive change over time than their counterparts. Discussion: These findings reveal the impact of racist U.S. policies enacted in the past that influence cognitive health over time and dementia risk later in life.

High-throughput measurement of elastic moduli of microfibers by rope coiling.

There are many fields where it is of interest to measure the elastic moduli of tiny fragile fibers, such as filamentous bacteria, actin filaments, DNA, carbon nanotubes, and functional microfibers. The elastic modulus is typically deduced from a sophisticated tensile test under a microscope, but the throughput is low and limited by the time-consuming and skill-intensive sample loading/unloading. Here, we demonstrate a simple microfluidic method enabling the high-throughput measurement of the elastic moduli of microfibers by rope coiling using a localized compression, where sample loading/unloading are not needed between consecutive measurements. The rope coiling phenomenon occurs spontaneously when a microfiber flows from a small channel into a wide channel. The elastic modulus is determined by measuring either the buckling length or the coiling radius. The throughput of this method, currently 3,300 fibers per hour, is a thousand times higher than that of a tensile tester. We demonstrate the feasibility of the method by testing a nonuniform fiber with axially varying elastic modulus. We also demonstrate its capability for in situ inline measurement in a microfluidic production line. We envisage that high-throughput measurements may facilitate potential applications such as screening or sorting by mechanical properties and real-time control during production of microfibers.

Are there sex differences in oxytocin and vasopressin V1a receptors ligand binding affinities?

BACKGROUND: There is substantial evidence for sex differences in the functioning of one of the most common receptor systems; G protein-coupled receptors (GPCRs). There are many points along the GPCR-mediated molecular signaling pathway at which males and females may differ, one of the first of which, chronologically, is in the stability of the interaction between the ligand and the receptor, or its binding affinity. Here we investigate the binding affinities of oxytocin (OT) and vasopressin (AVP) at the oxytocin receptor (OTR) and the vasopressin V1a receptor (V1aR), both of which are present in numerous in brain regions associated with social behavior. METHOD: In order to investigate sex- and estrous cycle-dependent differences in ligand-receptor binding affinity, male (n = 6) Syrian hamsters (Mesocricetus auratus), females on the day of estrus (E females, n = 6), and females on the second day of diestrus (D2 females n = 6) were chosen for study. Brains from hamsters were mounted on slides and competition and saturation binding assays were conducted. RESULTS: We report a remarkable similarity in the binding affinities of OT and AVP in males and females. Small differences were detected, however, in receptor and ligand specificity in females depending on whether they were in the estrous or diestrous stage of their ovulatory cycle. CONCLUSION: These data suggest that sex differences in binding affinity are not a likely source of the many sex differences that have been observed in the effects of OT and AVP in hamsters and other species.

The crystal structure of bacteriophage λ RexA provides novel insights into the DNA binding properties of Rex-like phage exclusion proteins.

RexA and RexB function as an exclusion system that prevents bacteriophage T4rII mutants from growing on Escherichia coli λ phage lysogens. Recent data established that RexA is a non-specific DNA binding protein that can act independently of RexB to bias the λ bistable switch toward the lytic state, preventing conversion back to lysogeny. The molecular interactions underlying these activities are unknown, owing in part to a dearth of structural information. Here, we present the 2.05-Å crystal structure of the λ RexA dimer, which reveals a two-domain architecture with unexpected structural homology to the recombination-associated protein RdgC. Modelling suggests that our structure adopts a closed conformation and would require significant domain rearrangements to facilitate DNA binding. Mutagenesis coupled with electromobility shift assays, limited proteolysis, and double electron-electron spin resonance spectroscopy support a DNA-dependent conformational change. In vivo phenotypes of RexA mutants suggest that DNA binding is not a strict requirement for phage exclusion but may directly contribute to modulation of the bistable switch. We further demonstrate that RexA homologs from other temperate phages also dimerize and bind DNA in vitro. Collectively, these findings advance our mechanistic understanding of Rex functions and provide new evolutionary insights into different aspects of phage biology.

Restoration of virulence in the attenuated Candid#1 vaccine virus requires reversion at both positions 168 and 427 in the envelope glycoprotein GPC.

Live-attenuated virus vaccines provide long-lived protection against viral disease but carry inherent risks of residual pathogenicity and genetic reversion. The live-attenuated Candid#1 vaccine was developed to protect Argentines against lethal infection by the Argentine hemorrhagic fever arenavirus, Junín virus. Despite its safety and efficacy in Phase III clinical study, the vaccine is not licensed in the US, in part due to concerns regarding the genetic stability of attenuation. Previous studies had identified a single F427I mutation in the transmembrane domain of the Candid#1 envelope glycoprotein GPC as the key determinant of attenuation, as well as the propensity of this mutation to revert upon passage in cell culture and neonatal mice. To ascertain the consequences of this reversion event, we introduced the I427F mutation into recombinant Candid#1 (I427F rCan) and investigated the effects in two validated small-animal models: in mice expressing the essential virus receptor (human transferrin receptor 1; huTfR1) and in the conventional guinea pig model. We report that I427F rCan displays only modest virulence in huTfR1 mice and appears attenuated in guinea pigs. Reversion at another attenuating locus in Candid#1 GPC (T168A) was also examined, and a similar pattern was observed. By contrast, virus bearing both revertant mutations (A168T+I427F rCan) approached the lethal virulence of the pathogenic Romero strain in huTfR1 mice. Virulence was less extreme in guinea pigs. Our findings suggest that genetic stabilization at both positions is required to minimize the likelihood of reversion to virulence in a second-generation Candid#1 vaccine.IMPORTANCELive-attenuated virus vaccines, such as measles/mumps/rubella and oral poliovirus, provide robust protection against disease but carry with them the risk of genetic reversion to the virulent form. Here, we analyze the genetics of reversion in the live-attenuated Candid#1 vaccine that is used to protect against Argentine hemorrhagic fever, an often-lethal disease caused by the Junín arenavirus. In two validated small-animal models, we find that restoration of virulence in recombinant Candid#1 viruses requires back-mutation at two positions specific to the Candid#1 envelope glycoprotein GPC, at positions 168 and 427. Viruses bearing only a single change showed only modest virulence. We discuss strategies to genetically harden Candid#1 GPC against these two reversion events in order to develop a safer second-generation Candid#1 vaccine virus.

Extensive Endolaser During Vitrectomy for Primary Rhegmatogenous Retinal Detachment Is Associated With Epiretinal Membrane Formation.

BACKGROUND AND OBJECTIVE: Epiretinal membrane (ERM) formation, a common complication following pars plana vitrectomy (PPV) for primary rhegmatogenous retinal detachment (RRD) repair, is associated with vision loss and metamorphopsias. Although laser retinopexy is generally associated with ERM formation, the correlation between the extent of laser treatment and ERM formation during PPV is not well established. The aim of this study was to identify risk factors associated with ERM formation including extend of endolaser retinopexy after PPV for primary RRD. PATIENTS AND METHODS: A retrospective, observational case series of 181 consecutive patients (185 eyes) who underwent PPV for primary RRD repair by a single surgeon was performed. Charts were reviewed by two independent reviewers, and de-identified data including patient characteristics and intraoperative findings such as number of laser spots placed were recorded. RESULTS: Postoperative ERM formation occurred in 75 eyes (40.5%) of which 68 (90.6%) were Stage 1, two (2.6%) were Stage 2, three (4%) were Stage 3, and two (2.6%) were Stage 4. Only one patient required secondary PPV for visually significant ERM. Patients with ERM had significantly more laser spots compared with patients with no ERM, with a mean of 807 and 519 laser spots respectively (95% CI: 387.6 to -187.3; P < 0.0001). Univariable analysis identified ≥750 endolaser spots (odds ratio [OR] = 4.0, 95% CI: 2.0 to 8.4; P < 0.0001), ≥4 retinal tears (OR = 2.8, 95%: CI 1.4 to 6.4; P = 0.005), and female sex (OR = 2.0, 95% CI: 1.1 to 3.7; P = 0.02) as significantly associated factors. After adjusting for potential confounding factors (ie, age, sex, macula status, lattice degeneration, length of symptoms, vitreous hemorrhage, number of endolaser spots, number of retinal tears) in multivariable logistic regression, ≥ 750 endolaser spots (OR = 2.4; P = 0.04) and female sex (OR = 2.4; P = 0.03) persisted as significant independent factors. CONCLUSIONS: Our study identified ≥ 750 laser spots and female sex as independent risk factors for ERM formation following PPV for RRD with an OR of 2.4 each. Although the incidence of ERM formation was generally high (40.5%), only one case required secondary PPV with ERM peeling, and visual outcomes were comparable between patients with and without ERM at final follow up. While endolaser photocoagulation is critical for successful RRD repair, consideration of the risk of ERM formation with extensive laser exposure is warranted. [Ophthalmic Surg Lasers Imaging Retina 2024;55:326-333.].

Rural Friendship Bench: A qualitative study in Zaka district, Zimbabwe.

BACKGROUND: We piloted the Friendship Bench-an evidence-based, urban-area task sharing intervention for common mental disorders-in rural Zimbabwe. The intervention combines problem solving therapy with income generating activities. This study sought to understand the intervention's implementation in terms of acceptability, feasibility, and sustainability as well as local attitudes towards mental wellbeing in rural Zimbabwe. METHODS: Using four separate semi-structured interview guides, we conducted in-depth interviews (N = 32) with patients (n = 9), village health workers (n = 12), nurses (n = 6), and community leaders (n = 5). We analyzed our data using thematic analysis with a diverse coding team using an integrative deductive-inductive approach. RESULTS: Five themes emerged: 1) explanatory models for mental illness, 2) clinical workflow and emphasis on documentation, 3) positive feedback about the Friendship Bench, 4) accessibility, and 5) feasibility. CONCLUSION: In its current format, our intervention was acceptable but neither feasible nor sustainable. Sociocultural context is critical in the development of rural task sharing interventions for mental health. We thus recommend a robust pilot and adaptation phase when scaling task sharing interventions in rural sub-Saharan Africa to elevate community voices, leverage existing social structures, and embed interventions as deeply into communities as possible.