bluuebunny/crossref_metadata_2025 huggingface dataset:
Apex predators and the facilitation of resource partitioning among mesopredators
Authors: Sivy Kelly J. , Pozzanghera Casey B. , Colson Kassidy E. , Mumma Matthew A. , Prugh Laura R.
Published: October 2017

Apex predators may influence carnivore communities through the suppression of competitively dominant mesopredators, however they also provide carrion subsidies that could influence foraging and competition among sympatric mesopredators when small prey is scarce. We assessed coyoteCanis latransand red foxVulpes vulpeswinter diet overlap and composition from scats collected in two study areas with 3‐fold difference in grey wolfCanis lupusdensity due to a wolf control program. We hypothesized that differences in diet composition would be driven by the use of carrion, and tested whether 1) apex predators facilitate resource overlap, or 2) apex predators facilitate resource partitioning. We estimated the available biomass of snowshoe hares and voles based on pellet density and vole capture rates in each study area. We used molecular analysis to confirm species identification of predator scats, and used microscopic evaluation of prey remains to analyze diet composition of 471 coyote and fox scats. Ungulate carrion, voles and snowshoe hares comprised 73% of coyote and fox diet, and differences in use of carrion and microtines accounted for nearly 60% of the dissimilarity in diet among these canids. Carrion was the top‐ranked item in the coyote diet in both study areas, whereas carrion use by red foxes declined 3‐fold in the study area with higher wolf and small prey abundance. Diet overlap tended to be lower and diet diversity tended to be higher where wolves were more abundant, though these trends were not statistically significant. Taken together, our findings indicate that carrion provisions could facilitate resource partitioning in mesocarnivore communities by alleviating exploitation competition for small mammals.
Predator foraging strategy mediates the effects of predators on local and emigrating prey
Authors: Warmbold Jerry W. , Wesner Jeff S.
Published: October 2017

Predation is a dominant structuring force in ecosystems, but its effects are almost always measured in the ecosystem of the predator. However, the effects of predators can potentially extend across ecosystem boundaries during ontogenetic niche shifts in prey. We compared the effects of fish predation on benthic versus emerging aquatic insects, and hypothesized that the relative effects of fish on these two stages of prey are mediated by fish foraging strategy (benthic versus water‐column feeders). Benthic‐feeding smallmouth buffalo reduced benthic insect biomass in the freshwater ecosystem by 89%, and reduced insect emergence to the terrestrial ecosystem by 65%. In contrast, water‐column feeding sunfish had no effect on benthic biomass in the freshwater ecosystem, but reduced emergence to the terrestrial ecosystem by 44% relative to the fishless control. When smallmouth and sunfish were combined in a substitutive design that kept total fish density the same as the single species treatments, their effects on benthic insects (50% reduction) were weaker than expected based on predictions from the single species treatments. In contrast, their combined effects on emergence (46% reduction) were additive. Tetragnathid spider densities increased during peak emergence, but did not respond to changes in emergence among treatments. These results demonstrate that the effects of fish on prey flux to the terrestrial ecosystem are not the same as their effects on benthic prey biomass in the aquatic ecosystem, and that this difference is likely mediated by foraging strategy.
Changes in paced signals may predict in‐hospital cardiac arrest
Authors: Attin Mina , Rosero Spencer Z. , Ding Jimmy , Nolan Scot , Tucker Rebecca
Published: October 2017

Background

An increasing number of patients with chronic illnesses have implanted cardiac rhythm devices such as pacemakers and implantable cardioverter‐defibrillators (ICDs). This study was conducted to identify potentially useful predictors of in‐hospital cardiac arrest (I‐HCA) within paced electrocardiogram (ECG) signals from cardiovascular patients with implanted medical devices.

Methods

In this retrospective study of 17 subjects, full‐disclosure ECG traces prior to the time of documented I‐HCA were analyzed to determine R‐R intervals and QRS durations (QRSd).

Results

Ventricular paced QRSd prolongation was observed prior to I‐HCA in 10/16 (63%) subjects. QRSd was significantly greater immediately preceding cardiac arrest than during each of the 8 hours prior to cardiac arrest (P < 0.05). Heart rate changes (measured using standard deviation) within 15 minutes of cardiac arrest were significantly greater in subjects with pulseless electrical activity (PEA)/asystolic arrest compared to those with cardiac arrests due to ventricular tachycardia/ventricular fibrillation (VT/VF) (10.13 vs 3.31; P  =  0.024). Significant differences over the 8 hours preceding cardiac arrest in heart rate (74 vs 86 beats/min; P  =  0.002) and QRS duration (172 ms vs 137 ms; P < 0.001) were observed between subjects with initial rhythms of VT/VF and those with initial rhythms of PEA/asystole.

Conclusions

Patterns of diagnostic ECG features can be extracted from the telemetry data of patients with implanted medical devices prior to adverse events including I‐HCA. The detection of these significant changes might have an immediate prognostic impact on the timely treatment of some patients at risk of adverse events.
Sputum TWEAK expression correlates with severity and degree of control in non‐eosinophilic childhood asthma
Authors: Kim Soo Yeon , Kim Jong Deok , Sol In Suk , Kim Min Jung , Kim Mi Na , Hong Jung Yeon , Kim Hye Ran , Kim Yoon Hee , Lee Yong Ju , Kim Kyung Won , Sohn Myung Hyun
Published: October 2017

Background

Tumor necrosis factor‐like weak inducer of apoptosis (TWEAK) is known to play a role in the pathogenesis of various inflammatory diseases. However, no study has been performed on childhood asthma.

Methods

Ninety‐five children with asthma and 78 controls aged 5‐18 years were included. Sputum induction, pulmonary function test (PFT), and methacholine challenge test were performed. The subjects were divided into the eosinophilic airway (EA) and non‐EA (NEA) groups based on sputum analysis and into the high and low TWEAK groups according to the TWEAK cutoff level (263.0 pg/mL). TWEAK in induced sputum supernatant was measured through enzyme‐linked immunosorbent assay.

Results

Children with asthma had higher TWEAK levels than healthy controls (493.0 [157.1‐904.3] vs 118.2 (67.5‐345.5) pg/mL, P < .001). Sputum TWEAK levels were significantly correlated with PFT parameters reflecting airway obstruction. This association was particularly prominent in subjects with NEA inflammation. Significant differences in FEF25‐75 (maximum mid‐expiratory flow, % predicted; P = .017), AX (reactance area; P < .001), R5‐R20 (difference between resistance at 5 and 20 Hz; P = .025), and X5 (reactance at 5 Hz, % predicted; P < .001) were noted between the high and low TWEAK groups within the NEA group. Sputum TWEAK level also showed significant positive correlations with asthma severity (r = .358, P = .001) and control status (r = .470, P < .001), distinctively in subjects with NEA inflammation.

Conclusions

Airway TWEAK may play a role in small airway inflammation especially in children with non‐eosinophilic asthma.
Sustained tachyarrhythmia in children younger than 1 year of age: Six year single‐center experience
Authors: Tunca Sahin Gulhan , Ozturk Erkut , Kasar Taner , Guzeltas Alper , Ergul Yakup
Published: October 2017

Background

The aim of this study was to evaluate the results of non‐operational sustained tachyarrhythmia in patients <1 year of age at the present center.

Methods

Between November 2010 and November 2016, the demographic characteristics, type and localization of the tachyarrhythmia, echocardiographic findings, and medical and/or ablation therapy for patients <1 year of age with sustained tachyarrhythmia were evaluated.

Results

Of 99 patients, 91 had sustained supraventricular tachycardia, and eight had sustained ventricular tachycardia. The median age was 30 days (range, 1–350 days), and the median weight was 4.2 kg (range, 2–13 kg). The common symptoms were palpitation and restlessness (n = 49, 49.5%), or the tachycardia was detected during routine inspection (n = 25, 25.3%) or fetal echocardiography (n = 11, 11.1%). Nineteen individuals (19%) had left ventricular (LV) dysfunction on first echocardiography. Twenty individuals had congenital heart disease. Common diagnoses were Wolff‐Parkinson‐White syndrome (n = 27), focal atrial tachycardia (n = 10), permanent junctional reciprocating tachycardia(n = 6), and atrial flutter (n = 6). Seventeen patients underwent medical therapy combined with cardioversion. The most commonly used abortive and acute therapy agents were adenosine, esmolol, and amiodarone. The most common combination therapy was propranolol and amiodarone, followed by a propranolol and propafenone combination. Nine individuals were treated with catheter ablation due to either resistance to medical therapy or LV dysfunction.

Conclusions

Tachyarrhythmias in children <1 year of age are mostly caused by accessory pathways and require multidrug therapy. Catheter ablation is an effective alternative therapy in the case of resistance to medical therapy and/or LV dysfunction.
Visually enhanced education and immunization perceptions in low‐income parents
Authors: Papapchrisanthou Michelle M. , Loman Deborah G.
Published: October 2017

Objective

Despite immunizations being an effective health promotion intervention, about 28% of children are not up‐to‐date on the combined seven‐vaccine series by 35 months of age in the United States. Identifying innovative techniques to increase immunization literacy is crucial to the health and well‐being of children.

Design and Sample

Based on the theory of multimedia learning, this study examined whether the use of visually enhanced education (VEE) positively impacted parental perception of immunization effectiveness, perceived knowledge of disease, comfort with immunization decision making, and satisfaction with the provider. Forty parents of infants 4–14 days old that could read English.

Intervention

Parents completed a questionnaire with 12 items in four categories during the initial visit (4–14 days old) before VEE and at the second visit (17–37 days later) after the second VEE session had been completed.

Results

A paired sample t test revealed a significant increase in two of the four categories (i.e., perceived knowledge of the disease [t(37) = 8.73, p = .000] and satisfaction with the provider [t(37) = 2.68, p = .011]. Cohen's effect size value suggested high practical significance in one of the four categories (i.e., perceived knowledge of disease d = 1.31, d = 1.42, d = 1.18, d = 1.05, d = 1.12). Cronbach's alpha for the 12 items was 0.852.

Conclusions

VEE may be an innovative technique for improving parental immunization health literacy and increasing parent‐professional communication about immunizations.
Small but attractive: female‐biased nectar production and floral visitors in a dimorphic shrub
Authors: Cervantes C. , Alvarez A. , Cuevas E.
Published: October 2017

In sexually dimorphic species, hermaphrodite flowers in gynodioecious species or male flowers in dioecious species are often larger and produce more nectar than their conspecific female flowers. As a consequence, hermaphrodite or male flowers frequently receive more pollinator visits.

Sex ratio, flower size, floral display, nectar production and floral visits were evaluated in two natural populations of Fuchsia thymifolia, a morphologically gynodioecious but functionally subdioecious insect‐pollinated shrub.

Sex ratio did not differ from the expected 1:1 in the two studied populations. As expected, hermaphrodite flowers were larger than female flowers, but in contrast to the general pattern, hermaphrodite flowers did not produce nectar or produced much less than female flowers. Flower visitors were flies (68%) and bumblebees (24%), both of which showed a preference for female flowers. No sex difference was detected in either flower longevity or floral display across the flowering season.

Higher nectar production by females may attract more pollinators, and may be a strategy to enhance female reproductive success in this species. Finally, floral dimorphism and insect preferences did not seem to hamper the maintenance of sub‐dioecy or prevent the evolution of dioecy in F. thymifolia.
Social Constraint and Self‐Doubt: Mechanisms of Social Network influence on Resistance to Persuasion
Authors: Levitan Lindsey Clark
Published: October 2017

Those around us have a profound influence on our political attitudes and attitude strength, such that people whose social networks include a variety of perspectives have weaker, less deeply entrenched attitudes than those who are surrounded by like‐minded others. In particular, those embedded in attitudinally heterogeneous networks are more open to changing their views. The nature and mechanisms of this network influence on openness to attitude change remain unclear. A survey experiment examines two mechanisms proposed by prior literature: (1) social doubt triggered by network members' dissent and (2) social constraint to maintain similar attitudes. It also provides some data on the more commonly assumed mechanism, (3) information exchange. Results strongly support social constraint and are mixed on social doubt. This contrasts with the theoretical emphasis of much previous interdisciplinary social network research, which has focused primarily on information exchange, to the detriment of other mechanisms. Findings also indicate that like‐minded social network members solidify attitudes at least as much as dissent erodes them, suggesting that prior emphasis on the influence of heterogeneous rather than attitudinally congruent networks is overstated. Implications for political movements are discussed.
Haptic augmented skin surface generation toward telepalpation from a mobile skin image
Authors: Kim K.
Published: October 2017

Background/purpose

Very little is known about the methods of integrating palpation techniques to existing mobile teleskin imaging that delivers low quality tactile information (roughness) for telepalpation. However, no study has been reported yet regarding telehaptic palpation using mobile phone images for teledermatology or teleconsultations of skincare.

Methods

This study is therefore aimed at introducing a new algorithm accurately reconstructing a haptic augmented skin surface for telehaptic palpation using a low‐cost clip‐on microscope simply attached to a mobile phone. Multiple algorithms such as gradient‐based image enhancement, roughness‐adaptive tactile mask generation, roughness‐enhanced 3D tactile map building, and visual and haptic rendering with a three‐degrees‐of‐freedom (DOF) haptic device were developed and integrated as one system.

Results

Evaluation experiments have been conducted to test the performance of 3D roughness reconstruction with/without the tactile mask. The results confirm that reconstructed haptic roughness with the tactile mask is superior to the reconstructed haptic roughness without the tactile mask. Additional experiments demonstrate that the proposed algorithm is robust against varying lighting conditions and blurring. In last, a user study has been designed to see the effect of the haptic modality to the existing visual only interface and the results attest that the haptic skin palpation can significantly improve the skin exam performance.

Conclusion

Mobile image‐based telehaptic palpation technology was proposed, and an initial version was developed. The developed technology was tested with several skin images and the experimental results showed the superiority of the proposed scheme in terms of the performance of haptic augmentation of real skin images.
Sensitive skin in Korean population: An epidemiological approach
Authors: Kim Y. R. , Cheon H. I. , Misery L. , Taieb C. , Lee Y. W.
Published: October 2017

Background/Purpose

Sensitive skin is characterized by uncomfortable sensations in response to multiple factors that do not normally have irritant properties. We used an epidemiological approach to evaluate the prevalence and characteristics of sensitive skin in a Korean population, and compared the results with those of populations from other countries.

Methods

A representative nationwide sample of 1000 Koreans aged ≥15 years was selected. The methodology used in this study (questionnaires) was the same as that used in similar studies conducted in other countries.

Results

Sensitive skin was present in 56.8% of the Koreans. The prevalence of sensitive skin was highest among countries such as the USA (44.6%), Europe (38.4%), Russia (39.7%), Brazil (34.2%), and Japan (54.5%). Participants with sensitive skin were more likely to accompany skin disorders than those with non‐sensitive skin (72.3% vs 38.0%; P < .001). Sensitive skin group were 2‐3 times more reactive to climatic and environmental factors, cosmetics, and food items than non‐sensitive skin group.

Conclusion

The prevalence of sensitive skin in Korea is the highest among countries in which such investigation has been conducted. The sensitive skin group appears more likely to experience dermatological reactions to unexpected factors than the non‐sensitive skin group.
Interpretation of low reactivity in the Abbott Architect rHTLV I/II assay
Authors: Tosswill J. H. C. , Taylor G. P.
Published: October 2017

Objective

The objective of this study is to reduce donor tissue wastage.

Aim

The aim of this study is to determine, in the case of the Abbott Architect rHTLV I/II assay, whether a signal/cut‐off (S/CO) ratio higher than the manufacturer's recommendation of 1·0 could be applied to diagnose significant HTLV‐1 seroreactivity.

Background

The detection of human T cell leukaemia virus type 1 (HTLV‐1) infection is primarily based on serology often utilising random access platforms. Although current assays have high sensitivity and specificity, in low‐prevalence regions, significant numbers of false‐positive reactions occur. A comprehensive follow‐up is difficult within the time frame of organ donation. This can lead to donor tissue wastage.

Methods

A retrospective analysis of 12 250 samples previously tested on the Abbott Architect rHTLV I/II platform and further tested by confirmatory serology/molecular detection to determine the sensitivity and positive predictive value in the S/CO ratio range was conducted.

Results

Where the sample S/CO ratio was >20 (n = 498), HTLV infection was confirmed in all but eight subjects. All of these eight had indeterminate confirmatory results, and none were found to be uninfected. Conversely, in the samples within the S/CO ratio range 1–4 (n = 271), no subject was subsequently found to be HTLV‐infected although HTLV infection could not be excluded in all cases, primarily due to lack of follow‐up samples (n = 60/271).

Conclusions

Samples with an S/CO ratio of <4·0 on the Abbott Architect rHTLV I/II platform represent a low risk of HTLV infection in the UK, and organs from such donors might reasonably be considered for transplantation, within the context of appropriate risk–benefit assessment.
Pre‐hospital transfusion of red blood cells in civilian trauma patients
Authors: Rehn M. , Weaver A. E. , Eshelby S. , Røislien J. , Lockey D. J.
Published: October 2017

Introduction

The current management of severely injured patients includes damage control resuscitation strategies that minimise the use of crystalloids and emphasise earlier transfusion of red blood cells (RBC) to prevent coagulopathy. In 2012, London's air ambulance (LAA) became the first UK civilian pre‐hospital service to routinely carry RBC to the trauma scene.

Objective

To investigate the effect of pre‐hospital RBC transfusion (phRTx) on overall blood product consumption.

Methods

A retrospective trauma database study compares before implementation with after implementation of phRTx in exsanguinating trauma patients transported directly to one major trauma centre. Pre‐hospital deaths were excluded. Univariate and multivariate Poisson regression analyses on data subject to multiple imputation were conducted.

Results

We included 137 and 128 patients in the before and after the implementation of phRTx groups, respectively. LAA transfused 304 RBC units (median 2, inter quartile range 1–3). We found a significant reduction in total RBC usage and reduced early use of platelets and fresh‐frozen plasma (FFP) after the implementation of phRTx in both univariate (P < 0·001) and multivariate analyses (P < 0·001). No immediate adverse transfusion reactions were identified.

Conclusion

Pre‐hospital trauma transfusion practice is feasible and associated with overall reduced RBC, platelets and FFP consumption.
The effect of fasting on gastrointestinal motility in healthy dogs as assessed by sonography
Authors: Sanderson Jillian J. , Boysen Søren R. , McMurray Jantina M. , Lee Albert , Stillion Jenefer R.
Published: October 2017

Objective

To evaluate the effect of fasting on gastrointestinal (GI) motility in healthy dogs, as detected by 2D ultrasound.

Design

Prospective observational study.

Setting

University Distributed Veterinary Learning Community.

Animals

Ten healthy client‐owned dogs.

Interventions

Dogs were fasted 24 hours following regular feeding. After this first feeding and during the 24 hour fasting period, 2D ultrasound was performed to detect sonographically visible GI contractions of the stomach, duodenum, and jejunum/ileum at T = 30 minutes, 6 hours, 12 hours, and 24 hours. Dogs were then fed a second meal after the 24‐hour fast and ultrasound was repeated 30 minutes later (T = 24.5 h). Each site was scanned twice at each time point. Each scan lasted 3 minutes. The results were averaged and then divided by 3 to determine contractions per minute. One‐way repeated measures ANOVA with post hoc Tukey's comparison test was used to detect statistical differences over time for each site examined.

Measurements and Main Results

The mean GI contraction rates in the stomach, duodenum, and jejunum/ileum at T12 and T24 were significantly lower than the GI contraction rates at T30, T3, T6, and T24.5 (P < 0.05). The mean GI contraction rates in the stomach, duodenum, and jejunum/ileum at T30, T3, T6, and T24.5 were not statistically different from each other.

Conclusions

Results of this study show that 2D sonography can be used to evaluate GI motility in dogs and that GI contraction rate decreases significantly in the stomach, duodenum, and jejunum/ileum after 12–24 hours of fasting.
Administration of platelet concentrates suspended in bicarbonated Ringer's solution in children who had platelet transfusion reactions
Authors: Kobayashi J. , Yanagisawa R. , Ono T. , Tatsuzawa Y. , Tokutake Y. , Kubota N. , Hidaka E. , Sakashita K. , Kojima S. , Shimodaira S. , Nakamura T.
Published: October 2017

Background and Objectives

Adverse reactions to platelet transfusions are a problem. Children with primary haematological and malignant diseases may experience allergic transfusion reactions (ATRs) to platelet concentrates (PCs), which can be prevented by giving washed PCs. A new platelet additive solution, using bicarbonated Ringer's solution and acid–citrate–dextrose formula A (BRS‐A), may be better for platelet washing and storage, but clinical data are scarce.

Materials and Methods

A retrospective cohort study for consecutive cases was performed between 2013 and 2017. For 24 months, we transfused washed PCs containing BRS‐A to children with primary haematological and malignant diseases and previous adverse reactions. Patients transfused with conventional PCs (containing residual plasma) were assigned as controls, and results were compared in terms of frequency of ATRs, corrected count increment (CCI) and occurrence of bleeding. We also studied children transfused with PCs washed by a different system as historical controls.

Results

Thirty‐two patients received 377 conventional PC transfusions. ATRs occurred in 12 (37·5%) patients from transfused with 18 (4·8%) bags. Thirteen patients, who experienced reactions to regular PCs in plasma, then received 119 transfusion bags of washed PCs containing BRS‐A, and none had ATRs to washed PCs containing BRS‐A. Before study period, six patients transfused 137 classical washed PCs with different platelet additive solution, under same indication, ATRs occurred in one (16·7%) patient from transfused with one (0·7%) bags. CCIs (24 h) in were lower with classical washed PCs (1·26 ± 0·54) compared to regular PCs in plasma (2·07 ± 0·76) (P < 0·001), but there was no difference between washed PCs containing BRS‐A (2·14 ± 0·77) and regular PCs (2·21 ± 0·79) (P = 0·769), and we saw no post‐transfusion bleeding.

Conclusion

Washed PCs containing BRS‐A appear to prevent ATRs without loss of transfusion efficacy in children with primary haematological and malignant diseases. Their efficacy should be further evaluated through larger prospective clinical trials.
Effects of carbon monoxide on early dysfunction and microangiopathy following GalT‐KO porcine pulmonary xenotransplantation in cynomolgus monkeys
Authors: Sahara Hisashi , Sekijima Mitsuhiro , Ariyoshi Yuichi , Kawai Akihiro , Miura Kohei , Waki Shiori , Nathan Louras , Tomita Yusuke , Iwanaga Takehiro , Nakano Kazuaki , Matsunari Hitomi , Date Hiroshi , Nagashima Hiroshi , Shimizu Akira , Yamada Kazuhiko
Published: October 2017

Background

Despite progress in the current genetic manipulation of donor pigs, most non‐human primates were lost within a day of receiving porcine lung transplants. We previously reported that carbon monoxide (CO) treatment improved pulmonary function in an allogeneic lung transplant (LTx) model using miniature swine. In this study, we evaluated whether the perioperative treatment with low‐dose inhalation of CO has beneficial effects on porcine lung xenografts in cynomolgus monkeys (cynos).

Methods

Eight cynos received orthotopic left LTx using either α‐1,3‐galactosyltransferase knockout (GalT‐KO; n = 2) or GalT‐KO with human decay accelerating factor (hDAF) (GalT‐KO/hDAF; n = 6) swine donors. These eight animals were divided into three groups. In Group 1 (n = 2), neither donor nor recipients received CO therapy. In Group 2 (n = 4), donors were treated with inhaled CO for 180‐minute. In Group 3 (n = 2), both donors and recipients were treated with CO (donor: 180‐minute; recipient: 360‐minute). Concentration of inhaled CO was adjusted based on measured levels of carboxyhemoglobin in the blood (15%‐20%).

Results

Two recipients survived for 3 days; 75 hours (no‐CO) and 80 hours (CO in both the donor and the recipient), respectively. Histology showed less inflammatory cell infiltrates, intravascular thrombi, and hemorrhage in the 80‐hour survivor with the CO treatment than the 75‐hours non‐CO treatment. Anti–non‐Gal cytotoxicity levels did not affect the early loss of the grafts. Although CO treatment did not prolong overall xeno lung graft survival, the recipient/donor CO treatment helped to maintain platelet counts and inhibit TNF‐α and IL‐6 secretion at 2 hours after revascularization of grafts. In addition, lung xenografts that were received recipient/donor CO therapy demonstrated fewer macrophage and neutrophil infiltrates. Infiltrating macrophages as well as alveolar epithelial cells in the CO‐treated graft expressed heme oxygenase‐1.

Conclusion

Although further investigation is required, CO treatment may provide a beneficial strategy for pulmonary xenografts.
Molecular Diagnostics of Arthroconidial Yeasts, Frequent Pulmonary Opportunists
Authors: Kaplan Engin , Al-Hatmi Abdullah M. S. , Ilkit Macit , Gerrits van den Ende A. H. G. , Hagen Ferry , Meis Jacques F. , de Hoog G. Sybren
Published: October 2017

Magnusiomyces capitatus
and
Saprochaete clavata
are members of the clade of arthroconidial yeasts that represent emerging opportunistic pulmonary pathogens in immunocompromised patients. Given that standard ribosomal DNA (rDNA) identification often provides confusing results, in this study, we analyzed 34 isolates with the goal of finding new genetic markers for classification using multilocus sequencing and amplified fragment length polymorphism (AFLP). The interspecific similarity obtained using rDNA markers (the internal transcribed spacer [ITS] and large subunit regions) was in the range of 96 to 99%, whereas that obtained using protein-coding loci (
Rbp2
,
Act
, and
Tef1α
) was lower at 89.4 to 95.2%. Ultimately,
Rbp2
was selected as the best marker for species distinction. On the basis of cloned ITS data, some strains proved to be misidentified in comparison with the identities obtained with phenotypic characters, protein sequences, and AFLP profiles, indicating that different copies of the ribosomal operon were present in a single species. Antifungal susceptibility testing revealed that voriconazole had the lowest MIC against
M. capitatus
, while amphotericin B had the lowest MIC against
S. clavata
. Both species exhibited
in vitro
resistance to fluconazole and micafungin.
Cryo-Electron Microscopy Structure of Porcine Deltacoronavirus Spike Protein in the Prefusion State
Authors: Shang Jian , Zheng Yuan , Yang Yang , Liu Chang , Geng Qibin , Tai Wanbo , Du Lanying , Zhou Yusen , Zhang Wei , Li Fang
Published: October 2017

Coronavirus spike proteins from different genera are divergent, although they all mediate coronavirus entry into cells by binding to host receptors and fusing viral and cell membranes. Here, we determined the cryo-electron microscopy structure of porcine deltacoronavirus (PdCoV) spike protein at 3.3-Å resolution. The trimeric protein contains three receptor-binding S1 subunits that tightly pack into a crown-like structure and three membrane fusion S2 subunits that form a stalk. Each S1 subunit contains two domains, an N-terminal domain (S1-NTD) and C-terminal domain (S1-CTD). PdCoV S1-NTD has the same structural fold as alpha- and betacoronavirus S1-NTDs as well as host galectins, and it recognizes sugar as its potential receptor. PdCoV S1-CTD has the same structural fold as alphacoronavirus S1-CTDs, but its structure differs from that of betacoronavirus S1-CTDs. PdCoV S1-CTD binds to an unidentified receptor on host cell surfaces. PdCoV S2 is locked in the prefusion conformation by structural restraint of S1 from a different monomeric subunit. PdCoV spike possesses several structural features that may facilitate immune evasion by the virus, such as its compact structure, concealed receptor-binding sites, and shielded critical epitopes. Overall, this study reveals that deltacoronavirus spikes are structurally and evolutionally more closely related to alphacoronavirus spikes than to betacoronavirus spikes; it also has implications for the receptor recognition, membrane fusion, and immune evasion by deltacoronaviruses as well as coronaviruses in general.

IMPORTANCE
In this study, we determined the cryo-electron microscopy structure of porcine deltacoronavirus (PdCoV) spike protein at a 3.3-Å resolution. This is the first atomic structure of a spike protein from the deltacoronavirus genus, which is divergent in amino acid sequences from the well-studied alpha- and betacoronavirus spike proteins. Here, we described the overall structure of the PdCoV spike and the detailed structure of each of its structural elements. Moreover, we analyzed the functions of each of the structural elements. Based on the structures and functions of these structural elements, we discussed the evolution of PdCoV spike protein in relation to the spike proteins from other coronavirus genera. This study combines the structure, function, and evolution of PdCoV spike protein and provides many insights into its receptor recognition, membrane fusion, and immune evasion.
Epistastic Interactions within the Junín Virus Envelope Glycoprotein Complex Provide an Evolutionary Barrier to Reversion in the Live-Attenuated Candid#1 Vaccine
Authors: York Joanne , Nunberg Jack H.
Published: October 2017

The Candid#1 strain of Junín virus was developed using a conventional attenuation strategy of serial passage in nonhost animals and cultured cells. The live-attenuated Candid#1 vaccine is used in Argentina to protect at-risk individuals against Argentine hemorrhagic fever, but it has not been licensed in the United States. Recent studies have revealed that Candid#1 attenuation is entirely dependent on a phenylalanine-to-isoleucine substitution at position 427 in the fusion subunit (GP2) of the viral envelope glycoprotein complex (GPC), thereby raising concerns regarding the potential for reversion to virulence. In this study, we report the identification and characterization of an intragenic epistatic interaction between the attenuating F427I mutation in GP2 and a lysine-to-serine mutation at position 33 in the stable signal peptide (SSP) subunit of GPC, and we demonstrate the utility of this interaction in creating an evolutionary barrier against reversion to the pathogenic genotype. In the presence of the wild-type F427 residue, the K33S mutation abrogates the ability of ectopically expressed GPC to mediate membrane fusion at endosomal pH. This defect is rescued by the attenuating F427I mutation. We show that the recombinant Candid#1 (rCan) virus bearing K33S GPC is viable and retains its attenuated genotype under cell culture conditions that readily select for reversion in the parental rCan virus. If back-mutation to F427 offers an accessible pathway to increase fitness in rCan, reversion in K33S-GPC rCan is likely to be lethal. The epistatic interaction between K33S and F427I thus may minimize the likelihood of reversion and enhance safety in a second-generation Candid#1 vaccine.

IMPORTANCE
The live-attenuated Candid#1 vaccine strain of Junín virus is used to protect against Argentine hemorrhagic fever. Recent findings that a single missense mutation in the viral envelope glycoprotein complex (GPC) is responsible for attenuation raise the prospect of facile reversion to pathogenicity. Here, we characterize a genetic interaction between GPC subunits that evolutionarily forces retention of the attenuating mutation. By incorporating this secondary mutation into Candid#1 GPC, we hope to minimize the likelihood of reversion and enhance safety in a second-generation Candid#1 vaccine. A similar approach may guide the design of live-attenuated vaccines against Lassa and other arenaviral hemorrhagic fevers.
Stability and Expression Levels of HLA-C on the Cell Membrane Modulate HIV-1 Infectivity
Authors: Parolini Francesca , Biswas Priscilla , Serena Michela , Sironi Francesca , Muraro Valentina , Guizzardi Elisabetta , Cazzoletti Lucia , Scupoli Maria Teresa , Gibellini Davide , Ugolotti Elisabetta , Biassoni Roberto , Beretta Alberto , Malnati Mauro , Romanelli Maria Grazia , Zipeto Donato
Published: October 2017

HLA-C expression is associated with a differential ability to control HIV-1 infection. Higher HLA-C levels may lead to better control of HIV-1 infection through both a higher efficiency of antigen presentation to cytotoxic T lymphocytes and the triggering of activating killer immunoglobulin-like receptors on NK cells, whereas lower levels may provide poor HIV-1 control and rapid progression to AIDS. We characterized the relative amounts of HLA-C heterotrimers (heavy chain/β2microglobulin [β2m]/peptide) and HLA-C free heavy chains on peripheral blood mononuclear cells (PBMCs) from healthy blood donors harboring both alleles with stable or unstable binding to β2m/peptide. We analyzed the stability of HLA-C heterotrimers of different allotypes and the infectivity of HIV-1 virions produced by PBMCs with various allotypes. We observed significant differences in HLA-C heterotrimer stability and in expression levels. We found that R5 HIV-1 virions produced by PBMCs harboring unstable HLA-C alleles were more infectious than those produced by PBMCs carrying the stable variants. We propose that HIV-1 infectivity might depend both on the amounts of HLA-C molecules and on their stability as trimeric complex. According to this model, individuals with low-expression HLA-C alleles and unstable binding to β2m/peptide might have worse control of HIV-1 infection and an intrinsically higher capacity to support viral replication.

IMPORTANCEFollowing HIV-1 infection, some people advance rapidly to AIDS while others have slow disease progression. HLA-C, a molecule involved in immunity, is a key determinant of HIV-1 control. Here we reveal how HLA-C variants contribute to the modulation of viral infectivity. HLA-C is present on the cell surface in two different conformations. The immunologically active conformation is part of a complex that includes β2microglobulin/peptide; the other conformation is not bound to β2microglobulin/peptide and can associate with HIV-1, increasing its infectivity. Individuals with HLA-C variants with a predominance of immunologically active conformations would display stronger immunity to HIV-1, reduced viral infectivity and effective control of HIV-1 infection, while subjects with HLA-C variants that easily dissociate from β2microglobulin/peptide would have a reduced immunological response to HIV-1 and produce more infectious virions. This study provides new information that could be useful in the design of novel vaccine strategies and therapeutic approaches to HIV-1.
Role of Granulocyte-Macrophage Colony-Stimulating Factor Production by T Cells duringMycobacterium tuberculosisInfection
Authors: Rothchild Alissa C. , Stowell Britni , Goyal Girija , Nunes-Alves Cláudio , Yang Qianting , Papavinasasundaram Kadamba , Sassetti Christopher M. , Dranoff Glenn , Chen Xinchun , Lee Jinhee , Behar Samuel M.
Published: October 2017

Mice deficient for granulocyte-macrophage colony-stimulating factor (GM-CSF−/−) are highly susceptible to infection withMycobacterium tuberculosis, and clinical data have shown that anti-GM-CSF neutralizing antibodies can lead to increased susceptibility to tuberculosis in otherwise healthy people. GM-CSF activates human and murine macrophages to inhibit intracellularM. tuberculosisgrowth. We have previously shown that GM-CSF produced by iNKT cells inhibits growth ofM. tuberculosis. However, the more general role of T cell-derived GM-CSF during infection has not been defined and how GM-CSF activates macrophages to inhibit bacterial growth is unknown. Here we demonstrate that, in addition to nonconventional T cells, conventional T cells also produce GM-CSF duringM. tuberculosisinfection. Early during infection, nonconventional iNKT cells and γδ T cells are the main source of GM-CSF, a role subsequently assumed by conventional CD4+T cells as the infection progresses.M. tuberculosis-specific T cells producing GM-CSF are also detected in the peripheral blood of infected people. Under conditions where nonhematopoietic production of GM-CSF is deficient, T cell production of GM-CSF is protective and required for control ofM. tuberculosisinfection. However, GM-CSF is not required for T cell-mediated protection in settings where GM-CSF is produced by other cell types. Finally, using anin vitromacrophage infection model, we demonstrate that GM-CSF inhibition ofM. tuberculosisgrowth requires the expression of peroxisome proliferator-activated receptor gamma (PPARγ). Thus, we identified GM-CSF production as a novel T cell effector function. These findings suggest that a strategy augmenting T cell production of GM-CSF could enhance host resistance againstM. tuberculosis.

IMPORTANCEMycobacterium tuberculosisis the bacterium that causes tuberculosis, the leading cause of death by any infection worldwide. T cells are critical components of the immune response toMycobacterium tuberculosis. While gamma interferon (IFN-γ) is a key effector function of T cells during infection, a failed phase IIb clinical trial and other studies have revealed that IFN-γ production alone is not sufficient to controlM. tuberculosis. In this study, we demonstrate that CD4+, CD8+, and nonconventional T cells produce GM-CSF duringMycobacterium tuberculosisinfection in mice and in the peripheral blood of infected humans. Under conditions where other sources of GM-CSF are absent, T cell production of GM-CSF is protective and is required for control of infection. GM-CSF activation of macrophages to limit bacterial growth requires host expression of the transcription factor PPARγ. The identification of GM-CSF production as a T cell effector function may inform future host-directed therapy or vaccine designs.
Genome-Wide Discovery of Genes Required for Capsule Production by Uropathogenic
Escherichia coli
Authors: Goh Kelvin G. K. , Phan Minh-Duy , Forde Brian M. , Chong Teik Min , Yin Wai-Fong , Chan Kok-Gan , Ulett Glen C. , Sweet Matthew J. , Beatson Scott A. , Schembri Mark A.
Published: October 2017

Uropathogenic
Escherichia coli
(UPEC) is a major cause of urinary tract and bloodstream infections and possesses an array of virulence factors for colonization, survival, and persistence. One such factor is the polysaccharide K capsule. Among the different K capsule types, the K1 serotype is strongly associated with UPEC infection. In this study, we completely sequenced the K1 UPEC urosepsis strain PA45B and employed a novel combination of a lytic K1 capsule-specific phage, saturated Tn
5
transposon mutagenesis, and high-throughput transposon-directed insertion site sequencing (TraDIS) to identify the complement of genes required for capsule production. Our analysis identified known genes involved in capsule biosynthesis, as well as two additional regulatory genes (
mprA
and
lrhA
) that we characterized at the molecular level. Mutation of
mprA
resulted in protection against K1 phage-mediated killing, a phenotype restored by complementation. We also identified a significantly increased unidirectional Tn
5
insertion frequency upstream of the
lrhA
gene and showed that strong expression of LrhA induced by a constitutive Pcl promoter led to loss of capsule production. Further analysis revealed loss of MprA or overexpression of LrhA affected the transcription of capsule biosynthesis genes in PA45B and increased sensitivity to killing in whole blood. Similar phenotypes were also observed in UPEC strains UTI89 (K1) and CFT073 (K2), demonstrating that the effects were neither strain nor capsule type specific. Overall, this study defined the genome of a UPEC urosepsis isolate and identified and characterized two new regulatory factors that affect UPEC capsule production.

IMPORTANCE
Urinary tract infections (UTIs) are among the most common bacterial infections in humans and are primarily caused by uropathogenic
Escherichia coli
(UPEC). Many UPEC strains express a polysaccharide K capsule that provides protection against host innate immune factors and contributes to survival and persistence during infection. The K1 serotype is one example of a polysaccharide capsule type and is strongly associated with UPEC strains that cause UTIs, bloodstream infections, and meningitis. The number of UTIs caused by antibiotic-resistant UPEC is steadily increasing, highlighting the need to better understand factors (e.g., the capsule) that contribute to UPEC pathogenesis. This study describes the original and novel application of lytic capsule-specific phage killing, saturated Tn
5
transposon mutagenesis, and high-throughput transposon-directed insertion site sequencing to define the entire complement of genes required for capsule production in UPEC. Our comprehensive approach uncovered new genes involved in the regulation of this key virulence determinant.
Sensory Repertoire of Bacterial Chemoreceptors
Authors: Ortega Álvaro , Zhulin Igor B. , Krell Tino
Published: October 2017

Chemoreceptors in bacteria detect a variety of signals and feed this information into chemosensory pathways that represent a major mode of signal transduction. The five chemoreceptors from
Escherichia coli
have served as traditional models in the study of this protein family. Genome analyses revealed that many bacteria contain much larger numbers of chemoreceptors with broader sensory capabilities. Chemoreceptors differ in topology, sensing mode, cellular location, and, above all, the type of ligand binding domain (LBD). Here, we highlight LBD diversity using well-established and emerging model organisms as well as genomic surveys. Nearly a hundred different types of protein domains that are found in chemoreceptor sequences are known or predicted LBDs, but only a few of them are ubiquitous. LBDs of the same class recognize different ligands, and conversely, the same ligand can be recognized by structurally different LBDs; however, recent studies began to reveal common characteristics in signal-LBD relationships. Although signals can stimulate chemoreceptors in a variety of different ways, diverse LBDs appear to employ a universal transmembrane signaling mechanism. Current and future studies aim to establish relationships between LBD types, the nature of signals that they recognize, and the mechanisms of signal recognition and transduction.
Does audit and feedback improve the adoption of recommended practices? Evidence from a longitudinal observational study of an emerging clinical network in Kenya
Authors: Gachau Susan , Ayieko Philip , Gathara David , Mwaniki Paul , Ogero Morris , Akech Samuel , Maina Michuki , Agweyu Ambrose , Oliwa Jacquie , Julius Thomas , Malla Lucas , Wafula James , Mbevi George , Irimu Grace , English Mike
Published: October 2017

Background

Audit and feedback (A&F) is widely used in healthcare but there are few examples of how to deploy it at scale in low-income countries. Establishing the Clinical Information Network (CIN) in Kenya provided an opportunity to examine the effect of A&F delivered as part of a wider set of activities to promote paediatric guideline adherence.

Methods

We analysed data collected from medical records on discharge for children aged 2–59 months from 14 Kenyan hospitals in the CIN. Hospitals joined CIN in phases and for each we analysed their initial 25 months of participation that occurred between December 2013 and March 2016. A total of 34 indicators of adherence to recommendations were selected for evaluation each classified by form of feedback (passive, active and none) and type of task (simple or difficult documentation and those requiring cognitive work). Performance change was explored graphically and using generalised linear mixed models with attention given to the effects of time and use of a standardised paediatric admission record (PAR) form.

Results

Data from 60 214 admissions were eligible for analysis. Adherence to recommendations across hospitals significantly improved for 24/34 indicators. Improvements were not obviously related to nature of feedback, may be related to task type and were related to PAR use in the case of documentation indicators. There was, however, marked variability in adoption and adherence to recommended practices across sites and indicators. Hospital-specific factors, low baseline performance and specific contextual changes appeared to influence the magnitude of change in specific cases.

Conclusion

Our observational data suggest some change in multiple indicators of adherence to recommendations (aspects of quality of care) can be achieved in low-resource hospitals using A&F and simple job aides in the context of a wider network approach.