Recognition of specific sialoglycan structures by oral streptococci impacts the severity of endocardial infection.

Streptococcus gordonii and Streptococcus sanguinis are primary colonizers of the tooth surface. Although generally non-pathogenic in the oral environment, they are a frequent cause of infective endocarditis. Both streptococcal species express a serine-rich repeat surface adhesin that mediates attachment to sialylated glycans on mucin-like glycoproteins, but the specific sialoglycan structures recognized can vary from strain to strain. Previous studies have shown that sialoglycan binding is clearly important for aortic valve infections caused by some S. gordonii, but this process did not contribute to the virulence of a strain of S. sanguinis. However, these streptococci can bind to different subsets of sialoglycan structures. Here we generated isogenic strains of S. gordonii that differ only in the type and range of sialoglycan structures to which they adhere and examined whether this rendered them more or less virulent in a rat model of endocarditis. The findings indicate that the recognition of specific sialoglycans can either enhance or diminish pathogenicity. Binding to sialyllactosamine reduces the initial colonization of mechanically-damaged aortic valves, whereas binding to the closely-related trisaccharide sialyl T-antigen promotes higher bacterial densities in valve tissue 72 hours later. A surprising finding was that the initial attachment of streptococci to aortic valves was inversely proportional to the affinity of each strain for platelets, suggesting that binding to platelets circulating in the blood may divert bacteria away from the endocardial surface. Importantly, we found that human and rat platelet GPIbα (the major receptor for S. gordonii and S. sanguinis on platelets) display similar O-glycan structures, comprised mainly of a di-sialylated core 2 hexasaccharide, although the rat GPIbα has a more heterogenous composition of modified sialic acids. The combined results suggest that streptococcal interaction with a minor O-glycan on GPIbα may be more important than the over-all affinity for GPIbα for pathogenic effects

Distribution of O-Acetylated Sialic Acids among Target Host Tissues for Influenza Virus.

Sialic acids (Sias) are important glycans displayed on the cells and tissues of many different animals and are frequent targets for binding and modification by pathogens, including influenza viruses. Influenza virus hemagglutinins bind Sias during the infection of their normal hosts, while the encoded neuraminidases and/or esterases remove or modify the Sia to allow virion release or to prevent rebinding. Sias naturally occur in a variety of modified forms, and modified Sias can alter influenza virus host tropisms through their altered interactions with the viral glycoproteins. However, the distribution of modified Sia forms and their effects on pathogen-host interactions are still poorly understood. Here we used probes developed from viral Sia-binding proteins to detect O-acetylated (4-O-acetyl, 9-O-acetyl, and 7,9-O-acetyl) Sias displayed on the tissues of some natural or experimental hosts for influenza viruses. These modified Sias showed highly variable displays between the hosts and tissues examined. The 9-O-acetyl (and 7,9-) modified Sia forms were found on cells and tissues of many hosts, including mice, humans, ferrets, guinea pigs, pigs, horses, dogs, as well as in those of ducks and embryonated chicken egg tissues and membranes, although in variable amounts. The 4-O-acetyl Sias were found in the respiratory tissues of fewer animals, being primarily displayed in the horse and guinea pig, but were not detected in humans or pigs. The results suggest that these Sia variants may influence virus tropisms by altering and selecting their cell interactions. IMPORTANCE Sialic acids (Sias) are key glycans that control or modulate many normal cell and tissue functions while also interacting with a variety of pathogens, including many different viruses. Sias are naturally displayed in a variety of different forms, with modifications at several positions that can alter their functional interactions with pathogens. In addition, Sias are often modified or removed by enzymes such as host or pathogen esterases or sialidases (neuraminidases), and Sia modifications can alter those enzymatic activities to impact pathogen infections. Sia chemical diversity in different hosts and tissues likely alters the pathogen-host interactions and influences the outcome of infection. Here we explored the display of 4-O-acetyl, 9-O-acetyl, and 7,9-O-acetyl modified Sia forms in some target tissues for influenza virus infection in mice, humans, birds, guinea pigs, ferrets, swine, horses, and dogs, which encompass many natural and laboratory hosts of those viruses

Doxycycline versus prednisolone as an initial treatment strategy for bullous pemphigoid: a pragmatic non-inferiority randomised controlled trial

Background: Bullous pemphigoid (BP) is a blistering skin disorder with increased mortality. We tested whether a strategy of starting treatment with doxycycline conveys acceptable short-term blister control whilst conferring long-term safety advantages over starting treatment with oral corticosteroids. Methods: Pragmatic multi-centre parallel-group randomised controlled trial of adults with BP (≥3 blisters ≥2 sites and linear basement membrane IgG/C3) plus economic evaluation. Participants were randomised to doxycycline (200 mg/day) or prednisolone (0·5 mg/kg/day). Localised adjuvant potent topical corticosteroids (<30 g/week) was permitted weeks 1-3. The non-inferiority primary effectiveness outcome was the proportion of participants with ≤3 blisters at 6 weeks. We assumed that doxycycline would be 25% less effective than corticosteroids with a 37% acceptable margin of noninferiority. The primary safety outcome was the proportion with severe, life-threatening or fatal treatment-related adverse events by 52 weeks. Analysis used a regression model adjusting for baseline disease severity, age and Karnofsky score, with missing data imputed. Results: 132 patients were randomised to doxycycline and 121 to prednisolone from 54 UK and 7 German dermatology centres. Mean age was 77·7 years and 68.4% had moderate to severe baseline disease. For those starting doxycycline, 83/112 (74·1%) had ≤3 blisters at 6 weeks compared with 92/101 (91·1%) for prednisolone, a difference of 18·6% favouring prednisolone (upper limit of 90% CI, 26·1%, within the predefined 37% margin). Related severe, life-threatening and fatal events at 52 weeks were 18·5% for those starting doxycycline and 36·6% for prednisolone (mITT analysis), an adjusted difference of 19·0% (95% CI, 7·9%, 30·1%, p=0·001). Conclusions: A strategy of starting BP patients on doxycycline is non-inferior to standard treatment with oral prednisolone for short-term blister control and significantly safer long-term

Novel gene function revealed by mouse mutagenesis screens for models of age-related disease

Determining the genetic bases of age-related disease remains a major challenge requiring a spectrum of approaches from human and clinical genetics to the utilization of model organism studies. Here we report a large-scale genetic screen in mice employing a phenotype-driven discovery platform to identify mutations resulting in age-related disease, both late-onset and progressive. We have utilized N-ethyl-N-nitrosourea mutagenesis to generate pedigrees of mutagenized mice that were subject to recurrent screens for mutant phenotypes as the mice aged. In total, we identify 105 distinct mutant lines from 157 pedigrees analysed, out of which 27 are late-onset phenotypes across a range of physiological systems. Using whole-genome sequencing we uncover the underlying genes for 44 of these mutant phenotypes, including 12 late-onset phenotypes. These genes reveal a number of novel pathways involved with age-related disease. We illustrate our findings by the recovery and characterization of a novel mouse model of age-related hearing loss

P2Y2 receptor activation regulates the expression of acetylcholinesterase and acetylcholine receptor genes at vertebrate neuromuscular junctions

ABSTRACT At the vertebrate neuromuscular junction (nmj), ATP is known to be coreleased with acetylcholine from the synaptic vesicles. We have previously shown that the P2Y 1 receptor is localized at the nmj. Here, we extend the findings to show that another nucleotide receptor, P2Y 2 , is also localized there and with P2Y 1 jointly mediates trophic responses to ATP. The P2Y 2 receptor mRNA in rat muscle increased during development and peaked in adulthood. The P2Y 2 receptor protein was shown to become restricted to the nmjs during embryonic development, in chick and in rat. In both rat and chick myotubes, P2Y 1 and P2Y 2 are expressed, increasing with differentiation, but P2Y 4 is absent. The P2Y 2 agonist UTP stimulated there inositol trisphosphate production and phosphorylation of extracellular signal-regulated kinases, in a dose-dependent manner. These UTP-induced responses were insensitive to the P2Y 1 -specific antagonist MRS 2179 (2Ј-deoxy-N 6 -methyl adenosine 3Ј,5Ј-diphosphate diammonium salt). In differentiated myotubes, P2Y 2 activation induced expression of acetylcholinesterase (AChE) protein (but not control ␣-tubulin). This was shown to arise from AChE promoter activation, mediated by activation of the transcription factor Elk-1. Two Elk-1-responsive elements, located in intron-1 of the AChE promoter, were found by mutation to act in this gene activation initiated at the P2Y 2 receptor and also in that initiated at the P2Y 1 receptor. Furthermore, the promoters of different acetylcholine receptor subunits were also stimulated by application of UTP to myotubes. These results indicate that ATP regulates postsynaptic gene expressions via a common pathway triggered by the activation of P2Y 1 and P2Y 2 receptors at the nmjs

First Phase 1 Double-Blind, Placebo-Controlled, Randomized Rectal Microbicide Trial Using UC781 Gel with a Novel Index of Ex Vivo Efficacy

Objectives: Successful control of the HIV/AIDS pandemic requires reduction of HIV-1 transmission at sexually-exposed mucosae. No prevention studies of the higher-risk rectal compartment exist. We report the first-in-field Phase 1 trial of a rectally-applied, vaginally-formulated microbicide gel with the RT-inhibitor UC781 measuring clinical and mucosal safety, acceptability and plasma drug levels. A first-in-Phase 1 assessment of preliminary pharmacodynamics was included by measuring changes in ex vivo HIV-1 suppression in rectal biopsy tissue after exposure to product in vivo. Methods: HIV-1 seronegative, sexually-abstinent men and women (N = 36) were randomized in a double-blind, placebo-controlled trial comparing UC781 gel at two concentrations (0.1%, 0.25%) with placebo gel (1:1:1). Baseline, single-dose exposure and a separate, 7-day at-home dosing were assessed. Safety and acceptability were primary endpoints. Changes in colorectal mucosal markers and UC781 plasma drug levels were secondary endpoints; ex vivo biopsy infectibility was an ancillary endpoint. Results: All 36 subjects enrolled completed the 7-14 week trial (100% retention) including 3 flexible sigmoidoscopies, each with 28 biopsies (14 at 10 cm; 14 at 30 cm). There were 81 Grade 1 adverse events (AEs) and 8 Grade 2; no Grade 3, 4 or procedure-related AEs were reported. Acceptability was high, including likelihood of future use. No changes in mucosal immunoinflammatory markers were identified. Plasma levels of UC781 were not detected. Ex vivo infection of biopsies using two titers of HIV-1 BaL showed marked suppression of p24 in tissues exposed in vivo to 0.25% UC781; strong trends of suppression were seen with the lower 0.1% UC781 concentration. Conclusions: Single and 7-day topical rectal exposure to both concentrations of UC781 were safe with no significant AEs, high acceptability, no detected plasma drug levels and no significant mucosal changes. Ex vivo biopsy infections demonstrated marked suppression of HIV infectibility, identifying a potential early biomarker of efficacy. (Registered at ClinicalTrials.gov; #NCT00408538). © 2011 Anton et al

Energetic particle influence on the Earth's atmosphere

This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Preliminary Field Observations of Meadow Vole Preferences among Selected Apple Clones

Damage by voles has continued to be a major cause of tree mortality American orchards despite nearly universal use of herbicides and rodenticide. (1,7). To reduce damage done by voles in infested orchards, one valuable tool could be use of a stock system that voles found highly unattractive. Having such stock systems in place would be particularly valuable during periods when the orchardist could neither bait nor spray for control. A cooperative VPI/Cornell research project initiated in 1974 identified a few cultivars with relatively high levels of resistance to pine voles, as expressed in free-choice tests under laboratory conditions. This work also provided data suggesting that such resistances to pine vole were simple inherited in Malus(2.6). Apple growers have long held that certain cultivars were attacked preferentially by meadow voles; \u27Hibernal\u27 and Mailing 9 (M.9) have been reported to be especially severely attacked. We initiated the study reported here to determine whether Malus clones consistently rejected by pine voles in free-choice situations in the Winchester laboratory tests would be similarly rejected by meadow voles under orchard conditions at Geneva