bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of Conserved E2 Residue W420 in Receptor Binding and Hepatitis C Virus Infection
Authors: Cowton Vanessa M. , Angus Allan G. N. , Cole Sarah J. , Markopoulou Christina K. , Owsianka Ania , Dunlop James I. , Gardner Deborah E. , Krey Thomas , Patel Arvind H. 
Published: June 2016

ABSTRACT
Hepatitis C virus (HCV) enters cells via interactions with several host factors, a key one being that between the viral E2 envelope glycoprotein and the CD81 receptor. We previously identified E2 tryptophan residue 420 (W420) as an essential CD81-binding residue. However, the importance of W420 in the context of the native virion is unknown, as those previous studies predate the infectious HCV cell culture (cell culture-derived HCV [HCVcc]) system. Here, we introduced four separate mutations (F, Y, A, or R) at position 420 within the infectious HCVcc JFH-1 genome and characterized their effects on the viral life cycle. While all mutations reduced E2-CD81 binding, only two (W420A and W420R) reduced HCVcc infectivity. Further analyses of mutants with hydrophobic residues (F or Y) found that interactions with the receptors SR-BI and CD81 were modulated, which in turn determined the viral uptake route. Both mutant viruses were significantly less dependent on SR-BI, and its lipid transfer activity, for virus entry. Furthermore, these viruses were resistant to the drug erlotinib, which targets epidermal growth factor receptor (EGFR) (a host cofactor for HCV entry) and also blocks SR-BI-dependent high-density lipoprotein (HDL)-mediated enhancement of virus entry. Together, our data indicate a model where an alteration at position 420 causes a subtle change in the E2 conformation that prevents interaction with SR-BI and increases accessibility to the CD81-binding site, in turn favoring a particular internalization route. These results further show that a hydrophobic residue with a strong preference for tryptophan at position 420 is important, both functionally and structurally, to provide an additional hydrophobic anchor to stabilize the E2-CD81 interaction.

IMPORTANCE
Hepatitis C virus (HCV) is a leading cause of liver disease, causing up to 500,000 deaths annually. The first step in the viral life cycle is the entry process. This study investigates the role of a highly conserved residue, tryptophan residue 420, of the viral glycoprotein E2 in this process. We analyzed the effect of changing this residue in the virus and confirmed that this region is important for binding to the CD81 receptor. Furthermore, alteration of this residue modulated interactions with the SR-BI receptor, and changes to these key interactions were found to affect the virus internalization route involving the host cofactor EGFR. Our results also show that the nature of the amino acid at this position is important functionally and structurally to provide an anchor point to stabilize the E2-CD81 interaction.
Structure and Genome Release Mechanism of the Human Cardiovirus Saffold Virus 3
Authors: Mullapudi Edukondalu , Nováček Jiří , Pálková Lenka , Kulich Pavel , Lindberg A. Michael , van Kuppeveld Frank J. M. , Plevka Pavel 
Published: June 2016

ABSTRACT

In order to initiate an infection, viruses need to deliver their genomes into cells. This involves uncoating the genome and transporting it to the cytoplasm. The process of genome delivery is not well understood for nonenveloped viruses. We address this gap in our current knowledge by studying the uncoating of the nonenveloped human cardiovirus Saffold virus 3 (SAFV-3) of the family
Picornaviridae
. SAFVs cause diseases ranging from gastrointestinal disorders to meningitis. We present a structure of a native SAFV-3 virion determined to 2.5 Å by X-ray crystallography and an 11-Å-resolution cryo-electron microscopy reconstruction of an “altered” particle that is primed for genome release. The altered particles are expanded relative to the native virus and contain pores in the capsid that might serve as channels for the release of VP4 subunits, N termini of VP1, and the RNA genome. Unlike in the related enteroviruses, pores in SAFV-3 are located roughly between the icosahedral 3- and 5-fold axes at an interface formed by two VP1 and one VP3 subunit. Furthermore, in native conditions many cardioviruses contain a disulfide bond formed by cysteines that are separated by just one residue. The disulfide bond is located in a surface loop of VP3. We determined the structure of the SAFV-3 virion in which the disulfide bonds are reduced. Disruption of the bond had minimal effect on the structure of the loop, but it increased the stability and decreased the infectivity of the virus. Therefore, compounds specifically disrupting or binding to the disulfide bond might limit SAFV infection.

IMPORTANCE
A capsid assembled from viral proteins protects the virus genome during transmission from one cell to another. However, when a virus enters a cell the virus genome has to be released from the capsid in order to initiate infection. This process is not well understood for nonenveloped viruses. We address this gap in our current knowledge by studying the genome release of
Human Saffold virus 3
. Saffold viruses cause diseases ranging from gastrointestinal disorders to meningitis. We show that before the genome is released, the Saffold virus 3 particle expands, and holes form in the previously compact capsid. These holes serve as channels for the release of the genome and small capsid proteins VP4 that in related enteroviruses facilitate subsequent transport of the virus genome into the cell cytoplasm.
Role for the αV Integrin Subunit in Varicella-Zoster Virus-Mediated Fusion and Infection
Authors: Yang Edward , Arvin Ann M. , Oliver Stefan L. 
Published: June 2016

ABSTRACT
Varicella-zoster virus (VZV) is an alphaherpesvirus that causes varicella and herpes zoster. Membrane fusion is essential for VZV entry and the distinctive syncytium formation in VZV-infected skin and neuronal tissue. Herpesvirus fusion is mediated by a complex of glycoproteins gB and gH-gL, which are necessary and sufficient for VZV to induce membrane fusion. However, the cellular requirements of fusion are poorly understood. Integrins have been implicated to facilitate entry of several human herpesviruses, but their role in VZV entry has not yet been explored. To determine the involvement of integrins in VZV fusion, a quantitative cell-cell fusion assay was developed using a VZV-permissive melanoma cell line. The cells constitutively expressed a reporter protein and short hairpin RNAs (shRNAs) to knock down the expression of integrin subunits shown to be expressed in these cells by RNA sequencing. The αV integrin subunit was identified as mediating VZV gB/gH-gL fusion, as its knockdown by shRNAs reduced fusion levels to 60% of that of control cells. A comparable reduction in fusion levels was observed when an anti-αV antibody specific to its extracellular domain was tested in the fusion assay, confirming that the domain was important for VZV fusion. In addition, reduced spread was observed in αV knockdown cells infected with the VZV pOka strain relative to that of the control cells. This was demonstrated by reductions in plaque size, replication kinetics, and virion entry in the αV subunit knockdown cells. Thus, the αV integrin subunit is important for VZV gB/gH-gL fusion and infection.

IMPORTANCE
Varicella-zoster virus (VZV) is a highly infectious pathogen that causes chickenpox and shingles. A common complication of shingles is the excruciating condition called postherpetic neuralgia, which has proven difficult to treat. While a vaccine is now available, it is not recommended for immunocompromised individuals and its efficacy decreases with the recipient's age. These limitations highlight the need for new therapies. This study examines the role of integrins in membrane fusion mediated by VZV glycoproteins gB and gH-gL, a required process for VZV infection. This knowledge will further the understanding of VZV entry and provide insight into the development of better therapies.
Changes in HIV-1 Capsid Stability Induced by Common Cytotoxic-T-Lymphocyte-Driven Viral Sequence Mutations
Authors: Schommers P. , Martrus G. , Matschl U. , Sirignano M. , Lütgehetmann M. , Richert L. , Hope T. J. , Fätkenheuer G. , Altfeld M. 
Published: June 2016

ABSTRACT
HIV-1-infected individuals with protective HLA class I alleles exhibit better control of viremia and slower disease progression. Virus control in these individuals has been associated with strong and potent HIV-1-specific cytotoxic-T-lymphocyte (CTL) responses restricted by protective HLA alleles, but control of viremia also occurs in the presence of selected CTL escape mutations. CTL escape mutations restricted by protective HLA class I molecules are frequently located in the conserved p24 Gag sequence of HIV-1 that encodes the conical capsid core and have been suggested to reduce viral replication capacity. In this study, the consequences of well-described CTL-associated p24 Gag sequence mutations for HIV-1 capsid stability were assessed using a cyclosporine (CsA) washout assay. The frequently occurring HLA-B57- and HLA-B27-associated CTL escape mutations T242N and R264K resulted in delayed capsid uncoating, suggesting modulation of capsid stability. The described compensatory mutations L268M and S173A observed in R264K viruses reconstituted the capsid-uncoating half-time. Interestingly, capsid stability was correlated with infectivity. Taken together, these data demonstrate that CTL-driven escape mutations within p24 Gag restricted by protective HLA class I alleles have a significant impact on capsid stability that might contribute to the persistent control of viral replication observed despite viral escape from CTL responses.

IMPORTANCE
Sequence mutations within p24 Gag selected by CTL responses restricted by protective HLA class I alleles have been associated with reduced viral fitness. However, the precise mechanisms underlying the reduced viral replication capacity and lower viral loads associated with these mutations remain unclear. Here, we demonstrate that dominant HLA-B27-associated CTL escape mutations within HIV-1 capsid lead to enhanced capsid rigidity, providing a possible mechanism for the reduced viral fitness of these variants.
Evidence that Receptor Destruction by the Sendai Virus Hemagglutinin-Neuraminidase Protein Is Responsible for Homologous Interference
Authors: Goto Hideo , Ohta Keisuke , Matsumoto Yusuke , Yumine Natsuko , Nishio Machiko 
Published: June 2016

ABSTRACT
Receptor destruction has been considered one of the mechanisms of homologous Sendai virus (SeV) interference. However, direct evidence of receptor destruction upon virus infection and its relevance to interference is missing. To investigate a precise mechanism of homologous interference, we established SeV persistently infected cells. The persistently infected cells inhibited superinfection by homologous SeV but supported replication of human parainfluenza virus 2 (hPIV2) and influenza A virus (IAV). We confirmed that SeV particles could not attach to or penetrate the infected cells and that the hemagglutinin-neuraminidase (HN) protein of SeV was involved in the interference. Lectin blot assays showed that the α2,3-linked sialic acids were specifically reduced in the SeV-infected cells, but the level of α2,6-linked sialic acids had not changed. As infection with IAV removed both α2,3- and α2,6-linked sialic acids, especially α2,3-linked sialic acids, IAV-infected cells inhibited superinfection of SeV. These results provide concrete evidence that destruction of the specific SeV receptor, α2,3-linked sialic acids, is relevant to homologous interference by SeV.

IMPORTANCE
Viral interference is a classically observed phenomenon, but the precise mechanism is not clear. Using SeV interference, we provide concrete evidence that reduction of the α2,3-linked sialic acid receptor by the HN of SeV is closely related with viral interference. Since SeV infection resulted in decrease of only α2,3-linked sialic acids, IAV, which also utilized α2,6-linked sialic acids to initiate infection, superinfected the SeV-infected cells. In contrast, SeV could not superinfect the IAV-infected cells because both α2,3- and α2,6-linked sialic acids were removed. These results indicate that receptor destruction critically contributes to viral interference.
Factors associated with prolonged length of stay following cardiac surgery in a major referral hospital in Oman: a retrospective observational study
Authors: Almashrafi Ahmed , Alsabti Hilal , Mukaddirov Mirdavron , Balan Baskaran , Aylin Paul 
Published: June 2016

ObjectivesTwo objectives were set for this study. The first was to identify factors influencing prolonged postoperative length of stay (LOS) following cardiac surgery. The second was to devise a predictive model for prolonged LOS in the cardiac intensive care unit (CICU) based on preoperative factors available at admission and to compare it against two existing cardiac stratification systems.DesignObservational retrospective study.SettingsA tertiary hospital in Oman.ParticipantsAll adult patients who underwent cardiac surgery at a major referral hospital in Oman between 2009 and 2013.Results30.5% of the patients had prolonged LOS (≥11 days) after surgery, while 17% experienced prolonged ICU LOS (≥5 days). Factors that were identified to prolong CICU LOS were non-elective surgery, current congestive heart failure (CHF), renal failure, combined coronary artery bypass graft (CABG) and valve surgery, and other non-isolated valve or CABG surgery. Patients were divided into three groups based on their scores. The probabilities of prolonged CICU LOS were 11%, 26% and 28% for group 1, 2 and 3, respectively. The predictive model had an area under the curve of 0.75. Factors associated with prolonged overall postoperative LOS included the body mass index, the type of surgery, cardiopulmonary bypass machine use, packed red blood cells use, non-elective surgery and number of complications. The latter was the most important determinant of postoperative LOS.ConclusionsPatient management can be tailored for individual patient based on their treatments and personal attributes to optimise resource allocation. Moreover, a simple predictive score system to enable identification of patients at risk of prolonged CICU stay can be developed using data that are routinely collected by most hospitals.
Consumer concerns about paracetamol: a retrospective analysis of a medicines call centre
Authors: Lau Stephanie M , McGuire Treasure M , van Driel Mieke L 
Published: June 2016

ObjectivesTo identify consumer information needs about paracetamol, the most commonly used analgesic and antipyretic worldwide.DesignRetrospective analysis of medicines questions from the public.SettingAustralian consumer medicines call centre.ParticipantsCallers to National Prescribing ServiceMedicines Linebetween September 2002 and June 2010 (n=123 217).Main outcome measuresEnquiry profile: demographics, enquiry type and concurrent medicines included in paracetamol calls; question themes derived from subset of call narratives.ResultsParacetamol comprised part of the enquiry in 5.2% of calls (n=6367). The caller age distribution for paracetamol calls was skewed towards a younger cohort, with 45.2% made by those aged 25–44 vs 37.5% in ‘rest of calls’. Significantly more paracetamol-related calls were made for a child (23.7%) compared with ‘rest of calls’ (12.7%, p<0.001). The most frequent concurrently asked about medicines were codeine (11%, n=1521) and ibuprofen (6.4%, n=884). Questions underpinned by paracetamol risk (interaction, use in pregnancy/lactation or other safety concerns) predominated (55.8%). When individual paracetamol enquiry types were compared with ‘rest of calls’, efficacy was most frequent (24.9% vs 22.8%); however, interaction (21.5% vs 14.8%), administration (15.5% vs 11%) and pregnancy/lactation (13.8% vs 8.3%) categories were more prevalent for paracetamol calls (all p<0.001). Enquiry type frequency also varied by patient age group, with questions about administration more common in younger groups and efficacy dominating in those over 45. Narrative analysis of over-represented paracetamol enquiry types showed specific concerns relevant to life stages: young children, those of reproductive age and the elderly.ConclusionsConsumers have many concerns about the use of paracetamol that may be under-recognised by healthcare providers, with the nature of enquiries differing across life stages. These concerns are not adequately addressed by available consumer information. Improving access to targeted information about paracetamol would promote the safe and effective use of this common medicine.
Visualising variation in mortality rates across the life course and by sex, USA and comparator states, 1933–2010
Authors: Vanderbloemen Laura , Dorling Danny , Minton Jonathan 
Published: June 2016

BackgroundPrevious research showed that younger adult males in the USA have, since the 1950s, died at a faster rate than females of the same age. In this paper, we quantify this difference, and explore possible explanations for the differences at different ages and in different years.MethodsUsing data from the Human Mortality Database (HMD), the number of additional male deaths per 10 000 female deaths was calculated for each year from 1933 to 2010, and for each year of age from 0 to 60 years, for the USA, and a number of other countries for comparison. The data were explored visually using shaded contour plots.ResultsGender differences in excess mortality have increased. Coming of age (between the ages of 15 and 25 years of age) is especially perilous for men relative to women now compared with the past in the USA; the visualisations highlight this change as important.ConclusionsSex differences in mortality risks at various ages are not static. While women may today have an advantage when it comes to life expectancy, in the USA, this has greatly increased since the 1930s. Just as young adulthood for women has been made safer through safer antenatal and childbirth practices, changes in public policy can make the social environment safer for men.
The association of grip strength from midlife onwards with all-cause and cause-specific mortality over 17 years of follow-up in the Tromsø Study
Authors: Strand Bjørn Heine , Cooper Rachel , Bergland Astrid , Jørgensen Lone , Schirmer Henrik , Skirbekk Vegard , Emaus Nina 
Published: June 2016

BackgroundGrip strength has consistently been found to predict all-cause mortality rates. However, few studies have examined cause-specific mortality or tested age differences in these associations.MethodsIn 1994, grip strength was measured in the population-based Tromsø Study, covering the ages 50–80 years (N=6850). Grip strength was categorised into fifths, and as z-scores. In this cohort study, models with all-cause mortality and deaths from specific causes as the outcome were performed, stratified by sex and age using Cox regression, adjusting for lifestyle-related and health-related factors.ResultsDuring 17 years of follow-up, 2338 participants died. A 1 SD reduction in grip strength was associated with HR=1.17 (95% CI 1.12 to 1.22) for all-cause mortality in a model adjusted for age, gender and body size. This association was similar across all age groups, in men and women, and robust to adjustment for a range of lifestyle-related and health-related factors. Results for deaths due to cardiovascular disease (CVD), respiratory diseases and external causes resembled those for all-cause mortality, while for cancer, the association was much weaker and not significant after adjustment for lifestyle-related and health-related factors.ConclusionsWeaker grip strength was associated with increased all-cause mortality rates, with similar effects on deaths due to CVD, respiratory disease and external causes, while a much weaker association was observed for cancer-related deaths. These associations were similar in both genders and across age groups, which supports the hypothesis that grip strength might be a biomarker of ageing over the lifespan.
Effects of new urban motorway infrastructure on road traffic accidents in the local area: a retrospective longitudinal study in Scotland
Authors: Olsen Jonathan R , Mitchell Richard , Mackay Daniel F , Humphreys David K , Ogilvie David 
Published: June 2016

BackgroundThe M74 motorway extension, Glasgow, opened in June 2011. One justification for construction was an expectation that it would reduce road traffic accidents (RTAs) on local non-motorway roads. This study evaluated the impact of the extension on the number of RTAs, stratifying by accident severity.MethodsData for the period 1997–2014 were extracted from a UK database of reported RTAs involving a personal injury. RTA severity was defined by the level of injury: minor, severe or fatal. RTAs were assigned to (1) the local area surrounding the motorway extension, (2) a comparator area surrounding an existing motorway or (3) a control area elsewhere in the conurbation. Interrupted time-series regression with autoregressive integrated moving average (ARIMA) errors was used to determine longitudinal between-area differences in change in the number of RTAs, which might indicate an intervention effect.ResultsGlasgow and surrounding local authorities saw a 50.6% reduction in annual RTAs (n: 5901 to 2914) between 1997 and 2014. In the intervention area, the number of recorded RTAs decreased by 50.7% (n: 758 to 374), and that of fatal/severe RTAs by 57.4% (n: 129 to 55), with similar reductions in the comparator/control areas. The interrupted time-series analysis showed no significant between-area differences in temporal trends. The reduction of pedestrian casualties was attenuated in the intervention area relative to Glasgow and surrounding authorities.ConclusionsReduction in RTAs was not associated with the motorway extension. Our findings suggest that in planning future investment, it should not be taken for granted that new road infrastructure alone will reduce RTAs in local areas. Urbanisation is proceeding rapidly worldwide, and evidence of infrastructure changes is lacking; this novel study provides important findings for future developments.