Explore the vast range of titles available.

Background A growing body of evidence suggests that use of race terms in spirometry reference equations underestimates disease burden in Black populations, which may lead to disparities in pulmonary disease outcomes. Data on asthma-specific health consequences of using race-adjusted spirometry are lacking. Methods We performed a secondary analysis of 163 children from two observational asthma studies to determine the frequencies of participants with ppFEV1 < 80% (consistent with uncontrolled asthma) or ppFEV1 ≥ 80% using race-specific (GLI-African American or Caucasian) vs. race-neutral (GLI-Global) spirometry and their alignment with indicators of asthma control (Asthma Control Test™, ACT). Comparisons of mean ppFEV1 values were conducted using Wilcoxon matched-pairs signed-rank tests. Two group comparisons were conducted using Wilcoxon rank-sum tests. Results Data from 163 children (100 Black, 63 White) were analyzed. Mean ppFEV 1 was 95.4% (SD 15.8) using race-specific spirometry and 90.4% (16.3) using race-neutral spirometry (p < 0.0001). Among 54 Black children with uncontrolled asthma (ACT ≤ 19), 20% had ppFEV1 < 80% using race-specific spirometry compared to 40% using race-neutral spirometry. In Black children with controlled asthma (ACT > 19), 87% had ppFEV1 ≥ 80% using race-specific compared to 67% using race-neutral spirometry. Children whose ppFEV1 changed to ≤ 80% with race-neutral spirometry had lower FEV1/FVC compared to those whose ppFEV1 remained ≥ 80% [0.83 (0.07) vs. 0.77 (0.05), respectively; p = 0.04], suggesting greater airway obstruction. Minimal changes in alignment of ppFEV1 with ACT score were observed for White children. Conclusions Use of race-specific reference equations in Black children may increase the risk of inappropriately labeling asthma as controlled.

Many Gram-negative bacteria, including causative agents of dysentery, plague, and typhoid fever, rely on a type III secretion system – a multi-membrane spanning syringe-like apparatus – for their pathogenicity. The cytosolic ATPase complex of this injectisome is proposed to play an important role in energizing secretion events and substrate recognition. We present the 3.3 Å resolution cryo-EM structure of the enteropathogenic Escherichia coli ATPase EscN in complex with its central stalk EscO. The structure shows an asymmetric pore with different functional states captured in its six catalytic sites, details directly supporting a rotary catalytic mechanism analogous to that of the heterohexameric F 1 /V 1 -ATPases despite its homohexameric nature. Situated at the C-terminal opening of the EscN pore is one molecule of EscO, with primary interaction mediated through an electrostatic interface. The EscN-EscO structure provides significant atomic insights into how the ATPase contributes to type III secretion, including torque generation and binding of chaperone/substrate complexes. Many Gram-negative bacteria rely on a type III secretion system (T3SS) for their pathogenicity. Here authors present the cryo-EM structure of the E.coli T3SS ATPase-central stalk complex, which forms a homohexameric, asymmetric pore with different functional states.

The pathway for the biosynthesis of the bacterial cell wall is one of the most prolific antibiotic targets, exemplified by the widespread use of β-lactam antibiotics. Despite this, our structural understanding of class A penicillin binding proteins, which perform the last two steps in this pathway, is incomplete due to the inherent difficulty in their crystallization and the complexity of their substrates. Here, we determine the near atomic resolution structure of the 83 kDa class A PBP from Escherichia coli , PBP1b, using cryogenic electron microscopy and a styrene maleic acid anhydride membrane mimetic. PBP1b, in its apo form, is seen to exhibit a distinct conformation in comparison to Moenomycin-bound crystal structures. The work herein paves the way for the use of cryoEM in structure-guided antibiotic development for this notoriously difficult to crystalize class of proteins and their complex substrates. Our structural understanding of class A penicillin binding proteins is incomplete due to the difficulty in their crystallization and the complexity of their substrates. Here, authors determine the structure of the 83 kDa class A PBP from Escherichia coli , PBP1b, using cryogenic electron microscopy and a styrene maleic acid anhydride membrane mimetic.

Background Although M. pneumoniae (M. pneumoniae) infections have been associated with various extrapulmonary manifestations, there have been very few documented cases of thrombotic events in pediatrics, and none to our knowledge with such extensive involvement as the patient described here. We aim to contribute to the urgency of discovering the mechanism of the coagulopathy associated with M. pneumoniae infections. Case presentation This 10-year-old boy was admitted after 2 weeks of fever, sore throat, worsening cough, and progressive neck and back pain. During hospitalization, he developed clots in several different organs: bilateral pulmonary emboli, cardiac vegetations, multiple splenic infarcts, and deep venous thromboses in three of four extremities. He was treated with long-term antibiotics and anticoagulation, and fully recovered. Conclusions This is the first case known to us of a child with an extensive number of thrombotic events in multiple anatomic sites associated with M. pneumoniae infection. The mechanism by which M. pneumoniae infection is related to thrombotic events is not fully understood, but there is evidence that the interplay between the coagulation pathways and the complement cascade may be significant. This patient underwent extensive investigation, and was found to have significant coagulopathy, but minimal complement abnormalities. By better understanding the mechanisms involved in complications of M. pneumoniae infection, the clinician can more effectively investigate the progression of this disease saving time, money, morbidity, and mortality.

The bacterial injectisome is a syringe-shaped macromolecular nanomachine utilized by many pathogenic Gram-negative bacteria, including the causative agents of plague, typhoid fever, whooping cough, sexually transmitted infections and major nosocomial infections. Bacterial proteins destined for self-assembly and host-cell targeting are translocated by the injectisome in a process known as type III secretion (T3S). The core structure is the ~4 MDa needle complex (NC), built on a foundation of three highly oligomerized ring-forming proteins that create a hollow scaffold spanning the bacterial inner membrane (IM) (24-mer ring-forming proteins PrgH and PrgK in the Salmonella enterica serovar Typhimurium Salmonella pathogenicity island 1 (SPI-1) type III secretion system (T3SS)) and outer membrane (OM) (15-mer InvG, a member of the broadly conserved secretin pore family). An internalized helical needle projects from the NC and bacterium, ultimately forming a continuous passage to the host, for delivery of virulence effectors. Here, we have captured snapshots of the entire prototypical SPI-1 NC in four distinct needle assembly states, including near-atomic resolution, and local reconstructions in the absence and presence of the needle. These structures reveal the precise localization and molecular interactions of the internalized SpaPQR ‘export apparatus’ complex, which is intimately encapsulated and stabilized within the IM rings in the manner of a nanodisc, and to which the PrgJ rod directly binds and functions as an initiator and anchor of needle polymerization. We also describe the molecular details of the extensive and continuous coupling interface between the OM secretin and IM rings, which is remarkably facilitated by a localized 16-mer stoichiometry in the periplasmic-most coupling domain of the otherwise 15-mer InvG oligomer. Cryo-EM imaging of the needle complex of the SPI-1 type III secretion system from Salmonella enterica serovar Typhimurium at different stages of complex assembly elucidates how needle assembly initiation is regulated and how the inner membrane and outer membrane rings of the complex interact, even with apparently incompatible symmetries.

Decentralized trial designs can improve accessibility and continuity of research participation by enabling remote data collection. This manuscript describes our team's experiences with remote data collection to identify acute asthma exacerbations in a clinical study as well as practical insights that support the continued optimization of remote methodologies. In this 12-month observational study, adolescents aged 12-21 years with persistent asthma and ≥1 exacerbation in the prior 24 months completed an initial in-person visit followed by monthly virtual visits. Participants used home spirometry, app-based symptom tracking, smart inhalers to monitor lung function and short-acting beta agonist (SABA) use, and self-collection of nasal epithelial lining fluid (NELF) samples. Exacerbations were defined by symptom/SABA thresholds or ≥20% FEV decline. Forty participants enrolled; 73% completed all visits. Median adherence to performance of daily spirometry and symptom surveys was 44% and 38%, respectively. Seventy-eight percent experienced ≥1 exacerbation. Of 132 alerts, 80% represented true exacerbations, primarily due to ≥20% FEV decline; erroneous alerts were linked to software errors and poor spirometry technique. Sixty-six NELF sample sets were collected and 50 were analyzed. Cytokine concentrations did not differ significantly between clinic-collected and self-collected samples. Technical challenges included device connectivity issues, erroneous alerts, and shipping delays. Decentralized study designs with remote data collection requires further study as a means of conducting clinical research in asthma that increases participant accessibility, representation and generalizability of trial results. This approach presents numerous challenges and requires further optimization to address adherence, technical complexity, and staff burden while maintaining scientific rigor.

We identified a stem cell donor with chromosomally integrated human herpesvirus (HHV)–6 and monitored the recipient for HHV-6 after transplantation. The appearance and subsequent increase in HHV-6 load paralleled engraftment and an increase in white blood cell count. Fluorescent in situ hybridization analysis showed integrated HHV-6 on chromosome band 17p13.3 in the donor and in the recipient after transplantation but not in the recipient before transplantation. The increase in viral load due to the genetic transmission of integrated HHV-6 could have been misinterpreted as substantial active infection and, thus, led to the administration of toxic antiviral therapy. We suggest that the confounding influence of integration be considered in laboratory investigations associating HHV-6 with disease

Polarized fluorescence microscopy is used to investigate the orientation of nucleoporins tagged with GFP within the nuclear pore complex in live yeast and mammalian cells, by analyzing the anisotropy pattern of the fluorophore. This approach can be applied to study other protein assemblies. The nuclear pore complex (NPC) perforates the nuclear envelope to facilitate selective transport between nucleus and cytoplasm. The NPC is composed of multiple copies of ∼30 different proteins, termed nucleoporins, whose arrangement within the NPC is an important unsolved puzzle in structural biology. Various alternative models for NPC architecture have been proposed but not tested experimentally in intact NPCs. We present a method using polarized fluorescence microscopy to investigate nucleoporin orientation in live yeast and mammalian cells. Our results support an arrangement of both yeast Nic96 and human Nup133–Nup107 in which their long axes are approximately parallel to the nuclear envelope plane. The method we developed can complement X-ray crystallography and electron microscopy to generate a high-resolution map of the entire NPC, and may be able to monitor nucleoporin rearrangements during nucleocytoplasmic transport and NPC assembly. This strategy can also be adapted for other macromolecular machines.

Human epidermal growth factor receptor 2 (HER2) is a receptor tyrosine kinase that plays an oncogenic role in breast, gastric and other solid tumors. However, anti-HER2 therapies are only currently approved for the treatment of breast and gastric/gastric esophageal junction cancers and treatment resistance remains a problem. Here, we engineer an anti-HER2 IgG1 bispecific, biparatopic antibody (Ab), zanidatamab, with unique and enhanced functionalities compared to both trastuzumab and the combination of trastuzumab plus pertuzumab (tras + pert). Zanidatamab binds adjacent HER2 molecules in trans and initiates distinct HER2 reorganization, as shown by polarized cell surface HER2 caps and large HER2 clusters, not observed with trastuzumab or tras + pert. Moreover, zanidatamab, but not trastuzumab nor tras + pert, elicit potent complement-dependent cytotoxicity (CDC) against high HER2-expressing tumor cells in vitro. Zanidatamab also mediates HER2 internalization and downregulation, inhibition of both cell signaling and tumor growth, antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP), and also shows superior in vivo antitumor activity compared to tras + pert in a HER2-expressing xenograft model. Collectively, we show that zanidatamab has multiple and distinct mechanisms of action derived from the structural effects of biparatopic HER2 engagement. The success of HER2-targeted cancer therapy is limited by treatment resistance. Here, the authors engineer an anti-HER2 biparatopic antibody with multiple mechanisms of action including induction of HER2 clustering to trigger complement dependent cytotoxicity, signal inhibition, antibody dependent cellular cytotoxicity and phagocytosis.

Cytomegalovirus end-organ disease can be prevented by giving ganciclovir when viraemia is detected in allograft recipients. Values of viral load correlate with development of end-organ disease and are moderated by pre-existing natural immunity. Our aim was to determine whether vaccine-induced immunity could do likewise. We undertook a phase-2 randomised placebo controlled trial in adults awaiting kidney or liver transplantation at the Royal Free Hospital, London, UK. Exclusion criteria were pregnancy, receipt of blood products (except albumin) in the previous 3 months, and simultaneous multiorgan transplantation. 70 patients seronegative and 70 seropositive for cytomegalovirus were randomly assigned from a scratch-off randomisation code in a 1:1 ratio to receive either cytomegalovirus glycoprotein-B vaccine with MF59 adjuvant or placebo, each given at baseline, 1 month and 6 months later. If a patient was transplanted, no further vaccinations were given and serial blood samples were tested for cytomegalovirus DNA by real-time quantitative PCR (rtqPCR). Any patient with one blood sample containing more than 3000 cytomegalovirus genomes per mL received ganciclovir until two consecutive undetectable cytomegalovirus DNA measurements. Safety and immunogenicity were coprimary endpoints and were assessed by intention to treat in patients who received at least one dose of vaccine or placebo. This trial is registered with ClinicalTrials.gov, NCT00299260. 67 patients received vaccine and 73 placebo, all of whom were evaluable. Glycoprotein-B antibody titres were significantly increased in both seronegative (geometric mean titre 12 537 (95% CI 6593–23 840) versus 86 (63–118) in recipients of placebo recipients; p<0·0001) and seropositive (118 395; 64 503–217 272) versus 24 682 (17 909–34 017); p<0·0001) recipients of vaccine. In those who developed viraemia after transplantation, glycoprotein-B antibody titres correlated inversely with duration of viraemia (p=0·0022). In the seronegative patients with seropositive donors, the duration of viraemia (p=0·0480) and number of days of ganciclovir treatment (p=0·0287) were reduced in vaccine recipients. Although cytomegalovirus disease occurs in the context of suppressed cell-mediated immunity post-transplantation, humoral immunity has a role in reduction of cytomegalovirus viraemia. Vaccines containing cytomegalovirus glycoprotein B merit further assessment in transplant recipients. National Institute of Allergy and Infectious Diseases, Grant R01AI051355 and Wellcome Trust, Grant 078332. Sponsor: University College London (UCL).