Viral envelope proteins fused to multiple distinct fluorescent reporters to probe receptor binding.

Enveloped viruses carry one or multiple proteins with receptor-binding functionalities. Functional receptors can be glycans, proteinaceous, or both; therefore, recombinant protein approaches are instrumental in attaining new insights regarding viral envelope protein receptor-binding properties. Visualizing and measuring receptor binding typically entails antibody detection or direct labeling, whereas direct fluorescent fusions are attractive tools in molecular biology. Here, we report a suite of distinct fluorescent fusions, both N- and C-terminal, for influenza A virus hemagglutinins and SARS-CoV-2 spike RBD. The proteins contained three or six fluorescent protein barrels and were applied directly to cells to assess receptor binding properties.

Real-world utilization of guideline-directed genetic testing in inherited cardiovascular diseases.

Background: Cardiovascular disease continues to be the leading cause of death globally. Clinical practice guidelines aimed at improving disease management and positively impacting major cardiac adverse events recommend genetic testing for inherited cardiovascular conditions such as dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), long QT syndrome (LQTS), hereditary amyloidosis, and familial hypercholesterolemia (FH); however, little is known about how consistently practitioners order genetic testing for these conditions in routine clinical practice. This study aimed to assess the adoption of guideline-directed genetic testing for patients diagnosed with DCM, HCM, LQTS, hereditary amyloidosis, or FH. Methods: This retrospective cohort study captured real-world evidence of genetic testing from ICD-9-CM and ICD-10-CM codes, procedure codes, and structured text fields of de-identified patient records in the Veradigm Health Insights Ambulatory EHR Research Database linked with insurance claims data. Data analysis was conducted using an automated electronic health record analysis engine. Patient records in the Veradigm database were sourced from more than 250,000 clinicians serving over 170 million patients in outpatient primary care and specialty practice settings in the United States and linked insurance claims data from public and private insurance providers. The primary outcome measure was evidence of genetic testing within six months of condition diagnosis. Results: Between January 1, 2017, and December 31, 2021, 224,641 patients were newly diagnosed with DCM, HCM, LQTS, hereditary amyloidosis, or FH and included in this study. Substantial genetic testing care gaps were identified. Only a small percentage of patients newly diagnosed with DCM (827/101,919; 0.8%), HCM (253/15,507; 1.6%), LQTS (650/56,539; 1.2%), hereditary amyloidosis (62/1,026; 6.0%), or FH (718/49,650; 1.5%) received genetic testing. Conclusions: Genetic testing is underutilized across multiple inherited cardiovascular conditions. This real-world data analysis provides insights into the delivery of genomic healthcare in the United States and suggests genetic testing guidelines are rarely followed in practice.

The smallest functional antibody fragment: Ultralong CDR H3 antibody knob regions potently neutralize SARS-CoV-2.

Cows produce antibodies with a disulfide-bonded antigen-binding domain embedded within ultralong heavy chain third complementarity determining regions. This "knob" domain is analogous to natural cysteine-rich peptides such as knottins in that it is small and stable but can accommodate diverse loops and disulfide bonding patterns. We immunized cattle with SARS-CoV-2 spike and found ultralong CDR H3 antibodies that could neutralize several viral variants at picomolar IC50 potencies in vitro and could protect from disease in vivo. The independent CDR H3 peptide knobs were expressed and maintained the properties of the parent antibodies. The knob interaction with SARS-CoV-2 spike was revealed by electron microscopy, X-ray crystallography, NMR spectroscopy, and mass spectrometry and established ultralong CDR H3-derived knobs as the smallest known recombinant independent antigen-binding fragment. Unlike other vertebrate antibody fragments, these knobs are not reliant on the immunoglobulin domain and have potential as a new class of therapeutics.

Applying Optical Tweezers with TIRF Microscopy to Quantify Physical Interactions Between Organelles in the Plant Endomembrane System.

Plant organelles are associated with each other through tethering proteins at membrane contact sites (MCS). Methods such as total internal reflection fluorescence (TIRF) optical tweezers allow us to probe organelle interactions in live plant cells. Optical tweezers (focused infrared laser beams) can trap organelles that have a different refractive index to their surrounding medium (cytosol), whilst TIRF allows us to simultaneously image behaviors of organelles in the thin region of cortical cytoplasm. However, few MCS tethering proteins have so far been identified and tested in a quantitative manner. Automated routines (such as setting trapping laser power and controlling the stage speed and distance) mean we can quantify organelle interactions in a repeatable and reproducible manner. Here we outline a series of protocols which describe laser calibrations required to collect robust data sets, generation of fluorescent plant material (Nicotiana tabacum, tobacco), how to set up an automated organelle trapping routine, and how to quantify organelle interactions (particularly organelle interactions with the endoplasmic reticulum). TIRF-optical tweezers enable quantitative testing of putative tethering proteins to reveal their role in plant organelle associations at MCS. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Microscope system set-up and stability Basic Protocol 2: Generation of transiently expressed fluorescent tobacco tissue by Agrobacterium-mediated infiltration Basic Protocol 3: Setting up an automated organelle trapping routine Basic Protocol 4: Quantifying organelle interactions.

When to Consider Lynch Syndrome in Non-Colon and Non-Endometrial Malignancies.

Lynch syndrome (LS) is a common genetic syndrome characterized by pathogenic mutations of DNA mismatch repair genes resulting in a hereditary predisposition to cancer. While typically associated with colonic and endometrial cancer, LS additionally influences the development of many other malignancies. The Amsterdam II and Revised Bethesda Guidelines are the established clinical criteria for diagnosing LS. These guidelines are based on the most general characteristics of LS and do not address specific characteristics of the less commonly LS-associated malignancies. For individuals that present initially with a non-colon and non-endometrial malignancy, recommendations and guidelines on when to consider screening for LS are limited. Therefore, it is essential that clinicians are familiar with distinct LS-associated patient- and tumor-specific characteristics, especially of the less common LS-associated cancers, so that LS's diagnosis is not missed. In this review article, we focus on extra-colonic and extra-endometrial LS-associated cancers, paying particular attention to any established or currently investigated cancer features that help raise suspicion for LS and potentially lead to its earlier diagnosis. This review will also discuss current guidelines specific to each LS-associated malignancy.

Association of Common Pediatric Surgeries With New Onset Chronic Pain in Patients 0-21 Years of Age in the United States.

Chronic pain (CP) is a major public health issue. While new onset CP is known to occur frequently after some pediatric surgeries, its incidence after the most common pediatric surgeries is unknown. This retrospective cohort study used insurance claims data from 2002 to 2017 for patients 0 to 21 years of age. The primary outcome was CP 90 to 365 days after each of the 20 most frequent surgeries in 5 age categories (identified using CP ICD codes). Multivariable logistic regression identified surgeries and risk factors associated with CP after surgery. A total of 424,590 surgical patients aged 0 to 21 were included, 22,361 of whom developed CP in the 90 to 365 days after surgery. The incidences of CP after surgery were: 1.1% in age group 0 to 1 years; 3.0% in 2 to 5 years; 5.6% in 6 to 11 years; 10.1% in 12 to 18 years; 9.9% in 19 to 21 years. Some surgeries and patient variables were associated with CP. Approximately 1 in 10 adolescents who underwent the most common surgeries developed CP, as did a striking percentage of children in other age groups. Given the long-term consequences of CP, resources should be allocated toward identification of high-risk pediatric patients and strategies to prevent CP after surgery. PERSPECTIVE: This study identifies the incidences of and risk factors for chronic pain after common surgeries in patients 0 to 21 years of age. Our findings suggest that resources should be allocated toward the identification of high-risk pediatric patients and strategies to prevent CP after surgery.

Induction of cross-neutralizing antibodies by a permuted hepatitis C virus glycoprotein nanoparticle vaccine candidate.

Hepatitis C virus (HCV) infection affects approximately 58 million people and causes ~300,000 deaths yearly. The only target for HCV neutralizing antibodies is the highly sequence diverse E1E2 glycoprotein. Eliciting broadly neutralizing antibodies that recognize conserved cross-neutralizing epitopes is important for an effective HCV vaccine. However, most recombinant HCV glycoprotein vaccines, which usually include only E2, induce only weak neutralizing antibody responses. Here, we describe recombinant soluble E1E2 immunogens that were generated by permutation of the E1 and E2 subunits. We displayed the E2E1 immunogens on two-component nanoparticles and these nanoparticles induce significantly more potent neutralizing antibody responses than E2. Next, we generated mosaic nanoparticles co-displaying six different E2E1 immunogens. These mosaic E2E1 nanoparticles elicit significantly improved neutralization compared to monovalent E2E1 nanoparticles. These results provide a roadmap for the generation of an HCV vaccine that induces potent and broad neutralization.

Structure of the hepatitis C virus E1E2 glycoprotein complex.

Hepatitis C virus (HCV) infection is a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma in humans and afflicts more than 58 million people worldwide. The HCV envelope E1 and E2 glycoproteins are essential for viral entry and comprise the primary antigenic target for neutralizing antibody responses. The molecular mechanisms of E1E2 assembly, as well as how the E1E2 heterodimer binds broadly neutralizing antibodies, remain elusive. Here, we present the cryo-electron microscopy structure of the membrane-extracted full-length E1E2 heterodimer in complex with three broadly neutralizing antibodies-AR4A, AT1209, and IGH505-at ~3.5-angstrom resolution. We resolve the interface between the E1 and E2 ectodomains and deliver a blueprint for the rational design of vaccine immunogens and antiviral drugs.

A clade C HIV-1 vaccine protects against heterologous SHIV infection by modulating IgG glycosylation and T helper response in macaques.

The rising global HIV-1 burden urgently requires vaccines capable of providing heterologous protection. Here, we developed a clade C HIV-1 vaccine consisting of priming with modified vaccinia Ankara (MVA) and boosting with cyclically permuted trimeric gp120 (CycP-gp120) protein, delivered either orally using a needle-free injector or through parenteral injection. We tested protective efficacy of the vaccine against intrarectal challenges with a pathogenic heterologous clade C SHIV infection in rhesus macaques. Both routes of vaccination induced a strong envelope-specific IgG in serum and rectal secretions directed against V1V2 scaffolds from a global panel of viruses with polyfunctional activities. Envelope-specific IgG showed lower fucosylation compared with total IgG at baseline, and most of the vaccine-induced proliferating blood CD4+ T cells did not express CCR5 and α4ß7, markers associated with HIV target cells. After SHIV challenge, both routes of vaccination conferred significant and equivalent protection, with 40% of animals remaining uninfected at the end of six weekly repeated challenges with an estimated efficacy of 68% per exposure. Induction of envelope-specific IgG correlated positively with G1FB glycosylation, and G2S2F glycosylation correlated negatively with protection. Vaccine-induced TNF-α+ IFN-γ+ CD8+ T cells and TNF-α+ CD4+ T cells expressing low levels of CCR5 in the rectum at prechallenge were associated with decreased risk of SHIV acquisition. These results demonstrate that the clade C MVA/CycP-gp120 vaccine provides heterologous protection against a tier2 SHIV rectal challenge by inducing a polyfunctional antibody response with distinct Fc glycosylation profile, as well as cytotoxic CD8 T cell response and CCR5-negative T helper response in the rectum.

Disparities in quality of life, social distress and employment outcomes in Australian cancer survivors.

PURPOSE: To examine how socio-demographic, comorbidities and information needs influence quality of life (QoL) outcomes of survivors of breast, colorectal, or prostate cancer, non-Hodgkin lymphoma or melanoma. METHODS: Cross-sectional postal survey with eligible participants identified through a population-based cancer registry. QoL outcomes were assessed by EQ-5D-5L, social difficulties index (SDI) and, for those employed at diagnosis, current employment. Regression analyses explored associations between outcome variables and cancer type, age, time since diagnosis, residential location, socio-economic disadvantage, comorbidities and unmet information needs. Mediation analyses examined whether comorbidities and information needs explained relationships between outcome variables and socio-economic disadvantage. RESULTS: 2115 survivors participated. Mean EQ-5D-5L scores (mean = 0.84) were similar to population averages and SDI scores were low for the entire sample (mean = 3.80). In multivariate analyses, being aged over 80, greater socio-economic disadvantage, comorbidities and unmet information needs decreased EQ-5D-5L scores. Higher SDI scores were associated with socio-economic disadvantage, comorbidities and unmet information needs. Not being employed was associated with being aged over 50, more comorbidities and socio-economic disadvantage. Comorbidities but not information needs partially mediated the impact of socio-economic disadvantage on EQ-5D-5L and SDI accounting for 17% and 14% of the total effect of socio-economic disadvantage respectively. Neither comorbidities nor information needs mediated the association between socio-economic disadvantage and employment outcomes. CONCLUSIONS: To improve quality of life, survivorship care should be better tailored to address the needs of individuals given their overall health and impact of comorbidities, their age and type of cancer and not simply time since diagnosis.

Single-molecule mechanical fingerprinting with DNA nanoswitch calipers.

Decoding the identity of biomolecules from trace samples is a longstanding goal in the field of biotechnology. Advances in DNA analysis have substantially affected clinical practice and basic research, but corresponding developments for proteins face challenges due to their relative complexity and our inability to amplify them. Despite progress in methods such as mass spectrometry and mass cytometry, single-molecule protein identification remains a highly challenging objective. Towards this end, we combine DNA nanotechnology with single-molecule force spectroscopy to create a mechanically reconfigurable DNA nanoswitch caliper capable of measuring multiple coordinates on single biomolecules with atomic resolution. Using optical tweezers, we demonstrate absolute distance measurements with ångström-level precision for both DNA and peptides, and using multiplexed magnetic tweezers, we demonstrate quantification of relative abundance in mixed samples. Measuring distances between DNA-labelled residues, we perform single-molecule fingerprinting of synthetic and natural peptides, and show discrimination, within a heterogeneous population, between different posttranslational modifications. DNA nanoswitch calipers are a powerful and accessible tool for characterizing distances within nanoscale complexes that will enable new applications in fields such as single-molecule proteomics.

Integrating 31-Gene Expression Profiling With Clinicopathologic Features to Optimize Cutaneous Melanoma Sentinel Lymph Node Metastasis Prediction.

National guidelines recommend sentinel lymph node biopsy (SLNB) be offered to patients with > 10% likelihood of sentinel lymph node (SLN) positivity. On the other hand, guidelines do not recommend SLNB for patients with T1a tumors without high-risk features who have < 5% likelihood of a positive SLN. However, the decision to perform SLNB is less certain for patients with higher-risk T1 melanomas in which a positive node is expected 5%-10% of the time. We hypothesized that integrating clinicopathologic features with the 31-gene expression profile (31-GEP) score using advanced artificial intelligence techniques would provide more precise SLN risk prediction. METHODS: An integrated 31-GEP (i31-GEP) neural network algorithm incorporating clinicopathologic features with the continuous 31-GEP score was developed using a previously reported patient cohort (n = 1,398) and validated using an independent cohort (n = 1,674). RESULTS: Compared with other covariates in the i31-GEP, the continuous 31-GEP score had the largest likelihood ratio (G2 = 91.3, P < .001) for predicting SLN positivity. The i31-GEP demonstrated high concordance between predicted and observed SLN positivity rates (linear regression slope = 0.999). The i31-GEP increased the percentage of patients with T1-T4 tumors predicted to have < 5% SLN-positive likelihood from 8.5% to 27.7% with a negative predictive value of 98%. Importantly, for patients with T1 tumors originally classified with a likelihood of SLN positivity of 5%-10%, the i31-GEP reclassified 63% of cases as having < 5% or > 10% likelihood of positive SLN, for a more precise, personalized, and clinically actionable SLN-positive likelihood estimate. CONCLUSION: These data suggest the i31-GEP could reduce the number of SLNBs performed by identifying patients with likelihood under the 5% threshold for performance of SLNB and improve the yield of positive SLNBs by identifying patients more likely to have a positive SLNB.

Chloroplasts alter their morphology and accumulate at the pathogen interface during infection by Phytophthora infestans.

Upon immune activation, chloroplasts switch off photosynthesis, produce antimicrobial compounds and associate with the nucleus through tubular extensions called stromules. Although it is well established that chloroplasts alter their position in response to light, little is known about the dynamics of chloroplast movement in response to pathogen attack. Here, we report that during infection with the Irish potato famine pathogen Phytophthora infestans, chloroplasts accumulate at the pathogen interface, associating with the specialized membrane that engulfs the pathogen haustorium. The chemical inhibition of actin polymerization reduces the accumulation of chloroplasts at pathogen haustoria, suggesting that this process is partially dependent on the actin cytoskeleton. However, chloroplast accumulation at haustoria does not necessarily rely on movement of the nucleus to this interface and is not affected by light conditions. Stromules are typically induced during infection, embracing haustoria and facilitating chloroplast interactions, to form dynamic organelle clusters. We found that infection-triggered stromule formation relies on BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED KINASE 1 (BAK1)-mediated surface immune signaling, whereas chloroplast repositioning towards haustoria does not. Consistent with the defense-related induction of stromules, effector-mediated suppression of BAK1-mediated immune signaling reduced stromule formation during infection. On the other hand, immune recognition of the same effector stimulated stromules, presumably via a different pathway. These findings implicate chloroplasts in a polarized response upon pathogen attack and point to more complex functions of these organelles in plant-pathogen interactions.

Prediction of Prolonged Opioid Use After Surgery in Adolescents: Insights From Machine Learning.

BACKGROUND: Long-term opioid use has negative health care consequences. Patients who undergo surgery are at risk for prolonged opioid use after surgery (POUS). While risk factors have been previously identified, no methods currently exist to determine higher-risk patients. We assessed the ability of a variety of machine-learning algorithms to predict adolescents at risk of POUS and to identify factors associated with this risk. METHODS: A retrospective cohort study was conducted using a national insurance claims database of adolescents aged 12-21 years who underwent 1 of 1297 surgeries, with general anesthesia, from January 1, 2011 to December 30, 2017. Logistic regression with an L2 penalty and with a logistic regression with an L1 lasso (Lasso) penalty, random forests, gradient boosting machines, and extreme gradient boosted models were trained using patient and provider characteristics to predict POUS (≥1 opioid prescription fill within 90-180 days after surgery) risk. Predictive capabilities were assessed using the area under the receiver-operating characteristic curve (AUC)/C-statistic, mean average precision (MAP); individual decision thresholds were compared using sensitivity, specificity, Youden Index, F1 score, and number needed to evaluate. The variables most strongly associated with POUS risk were identified using permutation importance. RESULTS: Of 186,493 eligible patient surgical visits, 8410 (4.51%) had POUS. The top-performing algorithm achieved an overall AUC of 0.711 (95% confidence interval [CI], 0.699-0.723) and significantly higher AUCs for certain surgeries (eg, 0.823 for spinal fusion surgery and 0.812 for dental surgery). The variables with the strongest association with POUS were the days' supply of opioids and oral morphine milligram equivalents of opioids in the year before surgery. CONCLUSIONS: Machine-learning models to predict POUS risk among adolescents show modest to strong results for different surgeries and reveal variables associated with higher risk. These results may inform health care system-specific identification of patients at higher risk for POUS and drive development of preventative measures.

Convergence of a common solution for broad ebolavirus neutralization by glycan cap-directed human antibodies.

Antibodies that target the glycan cap epitope on the ebolavirus glycoprotein (GP) are common in the adaptive response of survivors. A subset is known to be broadly neutralizing, but the details of their epitopes and basis for neutralization are not well understood. Here, we present cryoelectron microscopy (cryo-EM) structures of diverse glycan cap antibodies that variably synergize with GP base-binding antibodies. These structures describe a conserved site of vulnerability that anchors the mucin-like domains (MLDs) to the glycan cap, which we call the MLD anchor and cradle. Antibodies that bind to the MLD cradle share common features, including use of IGHV1-69 and IGHJ6 germline genes, which exploit hydrophobic residues and form ß-hairpin structures to mimic the MLD anchor, disrupt MLD attachment, destabilize GP quaternary structure, and block cleavage events required for receptor binding. Our results provide a molecular basis for ebolavirus neutralization by broadly reactive glycan cap antibodies.

Patient-reported outcomes in survivors of breast cancer one, three, and five years post-diagnosis: a cancer registry-based feasibility study.

INTRODUCTION AND AIMS: The burden of treatment toxicities in breast cancer requires longitudinal assessment of patient-centered outcomes. The current study aimed to assess the feasibility of collecting general and breast cancer-specific quality of life (QoL), ongoing symptoms and unmet needs, in patients identified from a population-based cancer registry, and to assess the contribution of demographic, disease, and care-related factors. METHODS: Eligible patients were identified from the Victorian Cancer Registry (Victoria, Australia) using the ICD-10 code C50, diagnosed during 2013, 2011, and 2009. Data included age, area of residence, cancer diagnosis, date of diagnosis, treatment modality, and staging. Patients completed a number of validated tools including the EQ-5D-5L and FACT-B, symptom items, and unmet needs. RESULTS: Of 1006 eligible patients, the overall response rate was 45.6%. Survivors 1 year post-diagnosis had significantly greater problems with pain or discomfort (59.2%) and with anxiety or depression (51.3%) compared with survivors 5 years post-diagnosis (45.1% with pain or discomfort, p < 0.05, and 32.7% with anxiety or depression, p < 0.01). For the 5 years group, pain or discomfort and anxiety or depression were significantly higher than for the general population (32.2% and 21.6%, respectively). Improved quality of life was found in those who did not receive chemotherapy (coefficient = 0.2269, p = 0.0409) and those who did not have a longstanding health condition (coefficient = 0.6342, p < 0.001). Poorer quality of life was associated with those who were not certain what was happening with their breast cancer (coefficient = - 0.3674, p = 0.0094) and those whose cancer had not been treated, had been treated but was still present, or had returned after treatment (coefficient = - 0.5314, p = 0.0136). Across the total cohort, women were bothered by changes in weight (21.3%) and concerned about the effects of stress on their cancer (19.6%). Fear of cancer recurrence was commonly reported and did not diminish over time (60.7%, 52.2%, and 56.9% at 1, 3, and 5 years, respectively). CONCLUSION: Collecting patient-reported outcomes from a population-based sample of breast cancer survivors was feasible. Physical symptoms and psychosocial issues are common and are persistent. Use of chemotherapy was the only treatment modality that significantly impacted on QoL.

The reaction of oleic acid monolayers with gas-phase ozone at the air water interface: the effect of sub-phase viscosity, and inert secondary components.

Organic films that form on atmospheric particulate matter change the optical and cloud condensation nucleation properties of the particulate matter and consequently have implications for modern climate and climate models. The organic films are subject to attack from gas-phase oxidants present in ambient air. Here we revisit in greater detail the oxidation of a monolayer of oleic acid by gas-phase ozone at the air-water interface as this provides a model system for the oxidation reactions that occur at the air-water interface of aqueous atmospheric aerosol. Experiments were performed on monolayers of oleic acid at the air-liquid interface at atmospherically relevant ozone concentrations to investigate if the viscosity of the sub-phase influences the rate of the reaction and to determine the effect of the presence of a second component within the monolayer, stearic acid, which is generally considered to be non-reactive towards ozone, on the reaction kinetics as determined by neutron reflectometry measurements. Atmospheric aerosol can be extremely viscous. The kinetics of the reaction were found to be independent of the viscosity of the sub-phase below the monolayer over a range of moderate viscosities, , demonstrating no involvement of aqueous sub-phase oxidants in the rate determining step. The kinetics of oxidation of monolayers of pure oleic acid were found to depend on the surface coverage with different behaviour observed above and below a surface coverage of oleic acid of ∼1 × 1018 molecule m-2. Atmospheric aerosol are typically complex mixtures, and the presence of an additional compound in the monolayer that is inert to direct ozone oxidation, stearic acid, did not significantly change the reaction kinetics. It is demonstrated that oleic acid monolayers at the air-water interface do not leave any detectable material at the air-water interface, contradicting the previous work published in this journal which the authors now believe to be erroneous. The combined results presented here indicate that the kinetics, and thus the atmospheric chemical lifetime for unsaturated surface active materials at the air-water interface to loss by reaction with gas-phase ozone, can be considered to be independent of other materials present at either the air-water interface or in the aqueous sub-phase.

Intramuscular progesterone in women with twins and a prior singleton spontaneous preterm birth.

BACKGROUND: Although the use of 17-alpha-hydroxyprogesterone caproate is one of the most commonly used strategies to reduce the risk of preterm birth since its approval by the Food and Drug Administration in 2011, there has been controversy recently that there may be no benefit associated with its use in singleton pregnancies in women with a prior history of spontaneous preterm birth. However, very few of these investigations evaluated the use of intramuscular progesterone in twin pregnancies. A few studies that used 17-alpha-hydroxyprogesterone caproate in twin pregnancies had mainly included unselected twin pregnancies. Although a twin pregnancy is independently associated with an increased likelihood of preterm birth, the primary indication for the use of supplemental progesterone in pregnancy is prior history of spontaneous preterm birth. Therefore, our investigation of weekly intramuscular progesterone in twin pregnancies with this birth history best addresses this question using a selected cohort. OBJECTIVE: To assess whether weekly 17-alpha-hydroxyprogesterone caproate prevents recurrent preterm birth in women with a current twin pregnancy and a prior singleton spontaneous preterm birth. STUDY DESIGN: This was a retrospective cohort study of women with twin pregnancy and a prior singleton spontaneous preterm birth in 2 institutions between January 2005 and December 2016. One group (intervention group) consisted of women who received weekly 17-alpha-hydroxyprogesterone caproate, whereas the other (control group) did not. The primary outcome was twin spontaneous preterm birth <34 weeks compared with odds ratio and adjusted odds ratio, adjusting for potential confounders. Secondary outcomes included composite neonatal morbidity such as respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, admission to the neonatal intensive care nursery, and fetal or neonatal death before hospital discharge. RESULTS: A total of 79 patients were included; 27 women received weekly 17-alpha-hydroxyprogesterone caproate and 52 did not. There were no statistically significant differences in maternal demographics except for age. Spontaneous preterm birth <34 weeks occurred in 16 patients (59%) in the intervention group vs 24 (46%) in the control group (odds ratio, 1.69; 95% confidence interval, 0.68-4.54). Composite neonatal morbidity occurred in 20 pregnancies (74%) in the intervention group and 41 pregnancies (79%) in the control group (odds ratio, 0.76; 95% confidence interval, 0.27-2.12). There remained no differences in outcomes after adjusting for potential confounders. CONCLUSION: In our study, weekly 17-alpha-hydroxyprogesterone caproate did not prevent spontaneous preterm birth or neonatal morbidity in women with twins and a prior singleton spontaneous preterm birth; however, further research with larger numbers and prospective design is needed.

A Strain-Specific Inhibitor of Receptor-Bound HIV-1 Targets a Pocket near the Fusion Peptide.

Disruption of viral fusion represents a viable, albeit under-explored, target for HIV therapeutics. Here, while studying the receptor-bound envelope glycoprotein conformation by cryoelectron microscopy (cryo-EM), we identify a pocket near the base of the trimer containing a bound detergent molecule and perform in silico drug screening by using a library of drug-like and commercially available molecules. After down-selection, we solve cryo-EM structures that validate the binding of two small molecule hits in very similar manners to the predicted binding poses, including interactions with aromatic residues within the fusion peptide. One of the molecules demonstrates low micromolar inhibition of the autologous virus by using a very rare phenylalanine in the fusion peptide and stabilizing the surrounding region. This work demonstrates that small molecules can target the fusion process, providing an additional target for anti-HIV therapeutics, and highlights the need to explore how fusion peptide sequence variations affect receptor-mediated conformational states across diverse HIV strains.