Survival of Staphylococcus aureus on sampling swabs stored at different temperatures.

AIMS: To understand the impact of storage temperature on recovery of Staphylococcus aureus on sampling swabs. Staphylococcus aureus is a common cause of skin and soft tissue infections, but also causes a variety of life-threatening diseases. With a large pool of asymptomatic carriers and transmission that can occur even through indirect contact, mitigation efforts have had limited success. Swab sampling, followed by culturing, is a cornerstone of epidemiological studies, however, S. aureus viability on swabs stored at different temperatures has not been characterized. METHODS AND RESULTS: We determined survival rates on swabs stored at five different temperatures. Samples stored at -70°C had no decay over time while samples stored at higher temperatures showed an exponential decay in viability. Mortality rates were greatest for swabs stored at 37°C. Survival at intermediate temperatures (-20 to 20·5°C) did not differ significantly, however, we observed more variation at higher temperatures. CONCLUSIONS: To maximize recovery of S. aureus cells, samples should be stored at -70°C or processed for culturing without delay. SIGNIFICANCE AND IMPACT OF THE STUDY: Epidemiological studies of bacterial diseases are typically limited to determination of pathogen presence/absence, yet quantitative assessments of pathogen load and genetic diversity can provide insights into disease progression and severity, likelihood of transmission and adaptive evolutionary potential. For studies of S. aureus where time or access to a microbiology laboratory may delay culturing, deep freezing or timely culturing will maximize the degree to which sampling results reflect source status.

The C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization.

The cosmic microwave background (CMB) B-mode signal is potentially weaker than the diffuse Galactic foregrounds over most of the sky at any frequency. A common method of separating the CMB from these foregrounds is via pixel-based parametric-model fitting. There are not currently enough all-sky maps to fit anything more than the most simple models of the sky. By simulating the emission in seven representative pixels, we demonstrate that the inclusion of a 5 GHz data point allows for more complex models of low-frequency foregrounds to be fitted than at present. It is shown that the inclusion of the C-BASS data will significantly reduce the uncertainties in a number of key parameters in the modelling of both the galactic foregrounds and the CMB. The extra data allow estimates of the synchrotron spectral index to be constrained much more strongly than is presently possible, with corresponding improvements in the accuracy of the recovery of the CMB amplitude. However, we show that to place good limits on models of the synchrotron spectral curvature will require additional low-frequency data.

Constraining the Neutron Star Compactness: Extraction of the

The ^{23}Al(p,γ)^{24}Si reaction is among the most important reactions driving the energy generation in type-I x-ray bursts. However, the present reaction-rate uncertainty limits constraints on neutron star properties that can be achieved with burst model-observation comparisons. Here, we present a novel technique for constraining this important reaction by combining the GRETINA array with the neutron detector LENDA coupled to the S800 spectrograph at the National Superconducting Cyclotron Laboratory. The ^{23}Al(d,n) reaction was used to populate the astrophysically important states in ^{24}Si. This enables a measurement in complete kinematics for extracting all relevant inputs necessary to calculate the reaction rate. For the first time, a predicted close-lying doublet of a 2_{2}^{+} and (4_{1}^{+},0_{2}^{+}) state in ^{24}Si was disentangled, finally resolving conflicting results from two previous measurements. Moreover, it was possible to extract spectroscopic factors using GRETINA and LENDA simultaneously. This new technique may be used to constrain other important reaction rates for various astrophysical scenarios.

The devil's in the dosing: severe drug-induced liver injury in a hydroxychloroquine-naive patient with subacute cutaneous lupus erythematosus and porphyria cutanea tarda.

A 29-year-old woman with a 1.5 year history of photosensitive skin lesions on her hands presented with a malar rash, bullous lesions on her hands, and was diagnosed with subacute lupus erythematosus after serologies revealed a positive antinuclear antibody test (1:2560), and antibodies to Ro/SSA and dsDNA. Hydroxychloroquine (400 mg/day) was prescribed and the patient developed severe drug-induced liver injury. Biopsy of her bullous skin lesions was consistent with porphyria cutanea tarda, as were her serological and urinary exams. She was successfully treated with therapeutic phlebotomy. This case identifies porphyria cutanea tarda as an important differential diagnosis for the rheumatologist to consider when evaluating patients with bullous skin lesions. Hydroxychloroquine in lower doses is an effective treatment for porphyria cutanea tarda; at doses used to treat systemic lupus erythematosus and subacute cutaneous lupus, there is a potentially life-threatening complication of hepatotoxicity.

Driving Protein Conformational Changes with Light: Photoinduced Structural Rearrangement in a Heterobimetallic Oxidase.

The heterobimetallic R2lox protein binds both manganese and iron ions in a site-selective fashion and activates oxygen, ultimately performing C-H bond oxidation to generate a tyrosine-valine cross-link near the active site. In this work, we demonstrate that, following assembly, R2lox undergoes photoinduced changes to the active site geometry and metal coordination motif. Through spectroscopic, structural, and mass spectrometric characterization, the photoconverted species is found to consist of a tyrosinate-bound iron center following light-induced decarboxylation of a coordinating glutamate residue and cleavage of the tyrosine-valine cross-link. This process occurs with high quantum efficiencies (Φ = 3%) using violet and near-ultraviolet light, suggesting that the photodecarboxylation is initiated via ligand-to-metal charge transfer excitation. Site-directed mutagenesis and structural analysis suggest that the cross-linked tyrosine-162 is the coordinating residue. One primary product is observed following irradiation, indicating potential use of this class of proteins, which contains a putative substrate channel, for controlled photoinduced decarboxylation processes, with relevance for in vivo functionality of R2lox as well as application in environmental remediation.

Time-Resolved Investigations of Heterobimetallic Cofactor Assembly in R2lox Reveal Distinct Mn/Fe Intermediates.

The assembly mechanism of the Mn/Fe ligand-binding oxidases (R2lox), a family of proteins that are homologous to the nonheme diiron carboxylate enzymes, has been investigated using time-resolved techniques. Multiple heterobimetallic intermediates that exhibit unique spectral features, including visible absorption bands and exceptionally broad electron paramagnetic resonance signatures, are observed through optical and magnetic resonance spectroscopies. On the basis of comparison to known diiron species and model compounds, the spectra have been attributed to (µ-peroxo)-MnIII/FeIII and high-valent Mn/Fe species. Global spectral analysis coupled with isotopic substitution and kinetic modeling reveals elementary rate constants for the assembly of Mn/Fe R2lox under aerobic conditions. A complete reaction mechanism for cofactor maturation that is consistent with experimental data has been developed. These results suggest that the Mn/Fe cofactor can perform direct C-H bond abstraction, demonstrating the potential for potent chemical reactivity that remains unexplored.

Belatacept Combined With Transient Calcineurin Inhibitor Therapy Prevents Rejection and Promotes Improved Long-Term Renal Allograft Function.

Belatacept, a T cell costimulation blocker, demonstrated superior renal function, lower cardiovascular risk, and improved graft and patient survival in renal transplant recipients. Despite the potential benefits, adoption of belatacept has been limited in part due to concerns regarding higher rates and grades of acute rejection in clinical trials. Since July 2011, we have utilized belatacept-based immunosuppression regimens in clinical practice. In this retrospective analysis of 745 patients undergoing renal transplantation at our center, we compared patients treated with belatacept (n = 535) with a historical cohort receiving a tacrolimus-based protocol (n = 205). Patient and graft survival were equivalent for all groups. An increased rate of acute rejection was observed in an initial cohort treated with a protocol similar to the low-intensity regimen from the BENEFIT trial versus the historical tacrolimus group (50.5% vs. 20.5%). The addition of a transient course of tacrolimus reduced rejection rates to acceptable levels (16%). Treatment with belatacept was associated with superior estimated GFR (belatacept 63.8 mL/min vs. tacrolimus 46.2 mL/min at 4 years, p < 0.0001). There were no differences in serious infections including rates of cytomegalovirus or BK viremia. We describe the development of a costimulatory blockade-based strategy that ultimately allows renal transplant recipients to achieve calcineurin inhibitor-free immunosuppression.

Unexpected Relations of Historical Anthrax Strain.

In 1998, it was claimed that an 80-year-old glass tube intentionally filled with Bacillus anthracis and embedded in a sugar lump as a WWI biological weapon still contained viable spores. Today, genome sequencing of three colonies isolated in 1998 and subjected to phylogenetic analysis surprisingly identified a well-known B. anthracis reference strain isolated in the United States in 1981, pointing to accidental laboratory contamination.IMPORTANCE Next-generation sequencing and subsequent phylogenetic analyses are useful and reliable tools for the classification of recent and historical samples. The reliability of sequences obtained and bioinformatic algorithms has increased in recent years, and research has uncovered the identity of a presumed bioweapon agent as a contaminant.

Experimental and DFT Investigations Reveal the Influence of the Outer Coordination Sphere on the Vibrational Spectra of Nickel-Substituted Rubredoxin, a Model Hydrogenase Enzyme.

Nickel-substituted rubredoxin (NiRd) is a functional enzyme mimic of hydrogenase, highly active for electrocatalytic and solution-phase hydrogen generation. Spectroscopic methods can provide valuable insight into the catalytic mechanism, provided the appropriate technique is used. In this study, we have employed multiwavelength resonance Raman spectroscopy coupled with DFT calculations on an extended active-site model of NiRd to probe the electronic and geometric structures of the resting state of this system. Excellent agreement between experiment and theory is observed, allowing normal mode assignments to be made on the basis of frequency and intensity analyses. Both metal-ligand and ligand-centered vibrational modes are enhanced in the resonance Raman spectra. The latter provide information about the hydrogen bonding network and structural distortions due to perturbations in the secondary coordination sphere. To reproduce the resonance enhancement patterns seen for high-frequency vibrational modes, the secondary coordination sphere must be included in the computational model. The structure and reduction potential of the NiIIIRd state have also been investigated both experimentally and computationally. This work begins to establish a foundation for computational resonance Raman spectroscopy to serve in a predictive fashion for investigating catalytic intermediates of NiRd.

Fc-Silent Anti-CD154 Domain Antibody Effectively Prevents Nonhuman Primate Renal Allograft Rejection.

The advent of costimulation blockade provides the prospect for targeted therapy with improved graft survival in transplant patients. Perhaps the most effective costimulation blockade in experimental models is the use of reagents to block the CD40/CD154 pathway. Unfortunately, successful clinical translation of anti-CD154 therapy has not been achieved. In an attempt to develop an agent that is as effective as previous CD154 blocking antibodies but lacks the risk of thromboembolism, we evaluated the efficacy and safety of a novel anti-human CD154 domain antibody (dAb, BMS-986004). The anti-CD154 dAb effectively blocked CD40-CD154 interactions but lacked crystallizable fragment (Fc) binding activity and resultant platelet activation. In a nonhuman primate kidney transplant model, anti-CD154 dAb was safe and efficacious, significantly prolonging allograft survival without evidence of thromboembolism (Median survival time 103 days). The combination of anti-CD154 dAb and conventional immunosuppression synergized to effectively control allograft rejection (Median survival time 397 days). Furthermore, anti-CD154 dAb treatment increased the frequency of CD4+ CD25+ Foxp3+ regulatory T cells. This study demonstrates that the use of a novel anti-CD154 dAb that lacks Fc binding activity is safe without evidence of thromboembolism and is equally as potent as previous anti-CD154 agents at prolonging renal allograft survival in a nonhuman primate preclinical model.

Attribution of net carbon change by disturbance type across forest lands of the conterminous United States.

BACKGROUND: Locating terrestrial sources and sinks of carbon (C) will be critical to developing strategies that contribute to the climate change mitigation goals of the Paris Agreement. Here we present spatially resolved estimates of net C change across United States (US) forest lands between 2006 and 2010 and attribute them to natural and anthropogenic processes. RESULTS: Forests in the conterminous US sequestered -460 ± 48 Tg C year-1, while C losses from disturbance averaged 191 ± 10 Tg C year-1. Combining estimates of net C losses and gains results in net carbon change of -269 ± 49 Tg C year-1. New forests gained -8 ± 1 Tg C year-1, while deforestation resulted in losses of 6 ± 1 Tg C year-1. Forest land remaining forest land lost 185 ± 10 Tg C year-1 to various disturbances; these losses were compensated by net carbon gains of -452 ± 48 Tg C year-1. C loss in the southern US was highest (105 ± 6 Tg C year-1) with the highest fractional contributions from harvest (92%) and wind (5%). C loss in the western US (44 ± 3 Tg C year-1) was due predominantly to harvest (66%), fire (15%), and insect damage (13%). The northern US had the lowest C loss (41 ± 2 Tg C year-1) with the most significant proportional contributions from harvest (86%), insect damage (9%), and conversion (3%). Taken together, these disturbances reduced the estimated potential C sink of US forests by 42%. CONCLUSION: The framework presented here allows for the integration of ground and space observations to more fully inform US forest C policy and monitoring efforts.

Triggered self-assembly of magnetic nanoparticles.

Colloidal magnetic nanoparticles are candidates for application in biology, medicine and nanomanufacturing. Understanding how these particles interact collectively in fluids, especially how they assemble and aggregate under external magnetic fields, is critical for high quality, safe, and reliable deployment of these particles. Here, by applying magnetic forces that vary strongly over the same length scale as the colloidal stabilizing force and then varying this colloidal repulsion, we can trigger self-assembly of these nanoparticles into parallel line patterns on the surface of a disk drive medium. Localized within nanometers of the medium surface, this effect is strongly dependent on the ionic properties of the colloidal fluid but at a level too small to cause bulk colloidal aggregation. We use real-time optical diffraction to monitor the dynamics of self-assembly, detecting local colloidal changes with greatly enhanced sensitivity compared with conventional light scattering. Simulations predict the triggering but not the dynamics, especially at short measurement times. Beyond using spatially-varying magnetic forces to balance interactions and drive assembly in magnetic nanoparticles, future measurements leveraging the sensitivity of this approach could identify novel colloidal effects that impact real-world applications of these nanoparticles.

Adaptive considerations of temperature dependence of neuromuscular function in two species of summer- and winter-caught Crab (Carcinus maenas and Cancer pagurus).

The aim of this study was to determine seasonal differences in the temperature dependence of neuromuscular parameters of the dactylopodite walking leg closer muscle in two species of freshly caught summer and winter decapod crabs. The relatively stenothermal Cancer pagurus (Cp) and eurythermal Carcinus maenas (Cm) muscle resting potential (RP) hyperpolarised significantly with increasing experimental temperature. The muscle RP in Cm was seasonally dependent at acute temperatures above 20 °C whereas in Cp no seasonal effect was observed. The latent period of the muscle excitatory junction potential (EJP) following tonic motor nerve stimulation was significantly longer in winter-caught crabs in both species, although the effect was significantly more marked in Cp than Cm. Summer-caught Cp had larger excitatory junction potentials (EJPs) than did winter-caught crabs, a seasonal effect not seen in Cm. In contrast, marked seasonal differences were found in the EJP decay time constant in Cm having significantly longer time constants in winter-caught crabs, where no seasonal difference was found in Cp. These results suggest that different seasonal effects of neuromuscular parameters between Cm and Cp may reflect different strategies of response to their different seasonal temperature environments.

Remote surveillance after colorectal cancer surgery: an effective alternative to standard clinic-based follow-up.

AIM: Most colorectal cancer recurrences are asymptomatic and are detected through routine postoperative clinic surveillance programmes with associated investigations. However, attendance at these clinics has a financial cost and may be associated with an increase in patient anxiety and dissatisfaction. The results of a remote follow-up system developed for selected patients are reported. METHOD: A remote surveillance programme has been in place in our institution for over 9 years. Patients having elective and emergency treatment for colorectal cancer were enrolled. The timeliness of the investigation, detection of local recurrence and distant metastases and overall 5-year survival rates were determined. A cost review and patient satisfaction survey were performed. RESULTS: The programme was suitable for over 900 patients who had received surgery for colorectal cancer between 2004 and 2012, representing some 50% of the total number of patients treated in this period. Of these, 811 (90%) had investigations carried out on time. Five-year survival rates were comparable with national data. Cost-minimization analysis demonstrated a financial saving of 63% and a 75% reduction in clinic appointments. High levels of overall patient satisfaction (97%) were noted with the programme. CONCLUSION: A remote surveillance system after colorectal cancer surgery is a safe and cost-effective alternative to traditional clinic-based follow up and has high patient satisfaction.

Tacrolimus to Belatacept Conversion Following Hand Transplantation: A Case Report.

Vascularized composite allotransplantation (VCA) has emerged as a viable limb replacement strategy for selected patients with upper limb amputation. However, allograft rejection has been seen in essentially all reported VCA recipients indicating a requirement for substantial immunosuppressive therapy. Calcineurin inhibitors have served as the centerpiece agent in all reported cases, and CNI-associated complications associated with the broad therapeutic effects and side effects of calcineurin inhibitors have been similarly common. Recently, belatacept has been approved as a calcineurin inhibitor replacement in kidney transplantation, but to date, its use in VCA has not been reported. Herein, we report on the case of a hand transplant recipient who developed recurrent acute rejection with alloantibody formation and concomitant calcineurin inhibitor nephrotoxicity, all of which resolved upon conversion from a maintenance regimen of tacrolimus, mycophenolate mofetil and steroids to belatacept and sirolimus. This case indicates that belatacept may be a reasonable maintenance immunosuppressive alternative for use in VCA, providing sufficient prophylaxis from rejection with a reduced side effect profile, the latter being particularly relevant for nonlife threatening conditions typically treated by VCA.

The effect of intramedullary pin size and monocortical screw configuration on locking compression plate-rod constructs in an in vitro fracture gap model.

OBJECTIVE: To investigate the effect of intramedullary pin size in combination with various monocortical screw configurations on locking compression plate-rod constructs. METHODS: A synthetic bone model with a 40 mm fracture gap was used. Locking compression plates with monocortical locking screws were tested with no pin (LCP-Mono) and intramedullary pins of 20% (LCPR-20), 30% (LCPR-30) and 40% (LCPR-40) of intramedullary diameter. Locking compression plates with bicortical screws (LCP-Bi) were also tested. Screw configurations with two or three screws per fragment modelled long (8-hole), intermediate (6-hole), and short (4-hole) plate working lengths. Responses to axial compression, biplanar four-point bending and axial load-to-failure were recorded. RESULTS: LCP-Bi were not significantly different from LCP-Mono control for any of the outcome variables. In bending, LCPR-20 were not significantly different from LCP-Bi and LCP-Mono. The LCPR-30 were stiffer than LCPR-20 and the controls. The LCPR-40 constructs were stiffer than all other constructs. The addition of an intramedullary pin of any size provided a significant increase in axial stiffness and load to failure. This effect was incremental with increasing intramedullary pin diameter. As plate working length decreased there was a significant increase in stiffness across all constructs. CLINICAL SIGNIFICANCE: A pin of any size increases resistance to axial loads whereas a pin of at least 30% intramedullary diameter is required to increase bending stiffness. Short plate working lengths provide maximum stiffness. However, the overwhelming effect of intramedullary pin size obviates the effect of changing working length on construct stiffness.

Nitric oxide availability is increased in contracting skeletal muscle from aged mice, but does not differentially decrease muscle superoxide.

Reactive oxygen and nitrogen species have been implicated in the loss of skeletal muscle mass and function that occurs during aging. Nitric oxide (NO) and superoxide are generated by skeletal muscle and where these are generated in proximity their chemical reaction to form peroxynitrite can compete with the superoxide dismutation to hydrogen peroxide. Changes in NO availability may therefore theoretically modify superoxide and peroxynitrite activities in tissues, but published data are contradictory regarding aging effects on muscle NO availability. We hypothesised that an age-related increase in NO generation might increase peroxynitrite generation in muscles from old mice, leading to an increased nitration of muscle proteins and decreased superoxide availability. This was examined using fluorescent probes and an isolated fiber preparation to examine NO content and superoxide in the cytosol and mitochondria of muscle fibers from adult and old mice both at rest and following contractile activity. We also examined the 3-nitrotyrosine (3-NT) and peroxiredoxin 5 (Prx5) content of muscles from mice as markers of peroxynitrite activity. Data indicate that a substantial age-related increase in NO levels occurred in muscle fibers during contractile activity and this was associated with an increase in muscle eNOS. Muscle proteins from old mice also showed an increased 3-NT content. Inhibition of NOS indicated that NO decreased superoxide bioavailability in muscle mitochondria, although this effect was not age related. Thus increased NO in muscles of old mice was associated with an increased 3-NT content that may potentially contribute to age-related degenerative changes in skeletal muscle.

A mathematical model of the human metabolic system and metabolic flexibility.

In healthy subjects some tissues in the human body display metabolic flexibility, by this we mean the ability for the tissue to switch its fuel source between predominantly carbohydrates in the postprandial state and predominantly fats in the fasted state. Many of the pathways involved with human metabolism are controlled by insulin and insulin-resistant states such as obesity and type-2 diabetes are characterised by a loss or impairment of metabolic flexibility. In this paper we derive a system of 12 first-order coupled differential equations that describe the transport between and storage in different tissues of the human body. We find steady state solutions to these equations and use these results to nondimensionalise the model. We then solve the model numerically to simulate a healthy balanced meal and a high fat meal and we discuss and compare these results. Our numerical results show good agreement with experimental data where we have data available to us and the results show behaviour that agrees with intuition where we currently have no data with which to compare.