Author Correction: Superluminal motion of a relativistic jet in the neutron-star merger GW170817.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Superluminal motion of a relativistic jet in the neutron-star merger GW170817.

The binary neutron-star merger GW1708171 was accompanied by radiation across the electromagnetic spectrum2 and localized2 to the galaxy NGC 4993 at a distance3 of about 41 megaparsecs from Earth. The radio and X-ray afterglows of GW170817 exhibited delayed onset4-7, a gradual increase8 in the emission with time (proportional to t0.8) to a peak about 150 days after the merger event9, followed by a relatively rapid decline9,10. So far, various models have been proposed to explain the afterglow emission, including a choked-jet cocoon4,8,11-13 and a successful-jet cocoon4,8,11-18 (also called a structured jet). However, the observational data have remained inconclusive10,15,19,20 as to whether GW170817 launched a successful relativistic jet. Here we report radio observations using very long-baseline interferometry. We find that the compact radio source associated with GW170817 exhibits superluminal apparent motion between 75 days and 230 days after the merger event. This measurement breaks the degeneracy between the choked- and successful-jet cocoon models and indicates that, although the early-time radio emission was powered by a wide-angle outflow8 (a cocoon), the late-time emission was most probably dominated by an energetic and narrowly collimated jet (with an opening angle of less than five degrees) and observed from a viewing angle of about 20 degrees. The imaging of a collimated relativistic outflow emerging from GW170817 adds substantial weight to the evidence linking binary neutron-star mergers and short γ-ray bursts.

A mildly relativistic wide-angle outflow in the neutron-star merger event GW170817.

GW170817 was the first gravitational-wave detection of a binary neutron-star merger. It was accompanied by radiation across the electromagnetic spectrum and localized to the galaxy NGC 4993 at a distance of 40 megaparsecs. It has been proposed that the observed γ-ray, X-ray and radio emission is due to an ultra-relativistic jet being launched during the merger (and successfully breaking out of the surrounding material), directed away from our line of sight (off-axis). The presence of such a jet is predicted from models that posit neutron-star mergers as the drivers of short hard-γ-ray bursts. Here we report that the radio light curve of GW170817 has no direct signature of the afterglow of an off-axis jet. Although we cannot completely rule out the existence of a jet directed away from the line of sight, the observed γ-ray emission could not have originated from such a jet. Instead, the radio data require the existence of a mildly relativistic wide-angle outflow moving towards us. This outflow could be the high-velocity tail of the neutron-rich material that was ejected dynamically during the merger, or a cocoon of material that breaks out when a jet launched during the merger transfers its energy to the dynamical ejecta. Because the cocoon model explains the radio light curve of GW170817, as well as the γ-ray and X-ray emission (and possibly also the ultraviolet and optical emission), it is the model that is most consistent with the observational data. Cocoons may be a ubiquitous phenomenon produced in neutron-star mergers, giving rise to a hitherto unidentified population of radio, ultraviolet, X-ray and γ-ray transients in the local Universe.

Magnetospherically driven optical and radio aurorae at the end of the stellar main sequence.

Aurorae are detected from all the magnetized planets in our Solar System, including Earth. They are powered by magnetospheric current systems that lead to the precipitation of energetic electrons into the high-latitude regions of the upper atmosphere. In the case of the gas-giant planets, these aurorae include highly polarized radio emission at kilohertz and megahertz frequencies produced by the precipitating electrons, as well as continuum and line emission in the infrared, optical, ultraviolet and X-ray parts of the spectrum, associated with the collisional excitation and heating of the hydrogen-dominated atmosphere. Here we report simultaneous radio and optical spectroscopic observations of an object at the end of the stellar main sequence, located right at the boundary between stars and brown dwarfs, from which we have detected radio and optical auroral emissions both powered by magnetospheric currents. Whereas the magnetic activity of stars like our Sun is powered by processes that occur in their lower atmospheres, these aurorae are powered by processes originating much further out in the magnetosphere of the dwarf star that couple energy into the lower atmosphere. The dissipated power is at least four orders of magnitude larger than what is produced in the Jovian magnetosphere, revealing aurorae to be a potentially ubiquitous signature of large-scale magnetospheres that can scale to luminosities far greater than those observed in our Solar System. These magnetospheric current systems may also play a part in powering some of the weather phenomena reported on brown dwarfs.

Coding of COPD Exacerbations and the Implications on Clinical Practice, Audit and Research.

International Classification of Disease 10 (ICD-10) codes record hospital admissions. We aimed to measure the accuracy of COPD exacerbation (ECOPD) codes and examine coding practices for COPD exacerbation.Prospective screening and ICD-10 codes were used to identify potential ECOPD within the DECAF internal validation cohort. Two coding searches were performed. The first search identified patients with an ECOPD discharge code, and a second, broad search was developed to identify all clinically confirmed ECOPD.717 of 1,122 (64%) patients with an ECOPD code had confirmed ECOPD. Common reasons for misclassification in the 405 patients who did not have an ECOPD included: lack of obstructive spirometry to diagnose COPD; and hospital admission due to progressive malignancy, asthma or cardiovascular disease. The broad search identified an additional 297 patients with ECOPD missed by the ECOPD codes. The vast majority of this group had pneumonia complicating ECOPD.ECOPD codes are insufficiently reliable to identify patients with clinically confirmed ECOPD for the purposes of audit or research. Search strategies should include pneumonia codes, specialist review of medical notes and spirometry confirmation of COPD.

An evaluation of methods for the isolation of nontuberculous mycobacteria from patients with cystic fibrosis, bronchiectasis and patients assessed for lung transplantation.

BACKGROUND: RGM medium is an agar-based, selective culture medium designed for the isolation of nontuberculous mycobacteria (NTM) from the sputum of patients with cystic fibrosis (CF). We evaluated RGM medium for the detection of NTM in patients with CF (405 samples), bronchiectasis (323 samples) and other lung diseases necessitating lung transplantation (274 samples). METHODS: In total, 1002 respiratory samples from 676 patients were included in the study. Direct culture on RGM medium, with incubation at two temperatures (30 °C and 37 °C), was compared with conventional culture of decontaminated samples for acid-fast bacilli (AFB) using both a solid medium (Löwenstein-Jensen medium) and a liquid medium (the Mycobacterial Growth Indicator Tube; MGIT). RESULTS: For all three patient groups, significantly more isolates of NTM were recovered using RGM medium incubated at 30 °C than by any other method (sensitivity: 94.6% vs. 22.4% for conventional AFB culture; P < 0.0001). Significantly more isolates of Mycobacterium abscessus complex were isolated on RGM at 30 °C than by AFB culture (sensitivity: 96.1% vs. 58.8%; P < 0.0001). The recovery of Mycobacterium avium complex was also greater using RGM medium at 30 °C compared to AFB culture (sensitivity: 83% vs. 70.2%), although this difference was not statistically significant and a combination of methods was necessary for optimal recovery (P = 0.21). CONCLUSIONS: In the largest study of RGM medium to date, we reaffirm its utility for isolation of NTM from patients with CF. Furthermore; we show that it also provides an effective tool for culture of respiratory samples from patients with bronchiectasis and other lung diseases.

Magnetic conjugated polymer nanoparticles doped with a europium complex for biomedical imaging.

Self-assembling conjugated polymer nanoparticles containing PVK and PLGA-PEG as a matrix polymer were doped with both a luminescent rare-earth complex and magnetic nanoparticles (SPIONs), giving rise to materials that are both luminescent and magnetic. Nanoparticle sizes ranged from 80-110 nm without SPIONs and showed an increase in size (200-1000 nm) with additional SPION content (11-54%). Quantum yields (QYs) of 24% and 18% were measured for systems without and with 11% SPIONs, respectively. Optical properties were stable and suitable for biological imaging applications.

The PEARL score predicts 90-day readmission or death after hospitalisation for acute exacerbation of COPD.

BACKGROUND: One in three patients hospitalised due to acute exacerbation of COPD (AECOPD) is readmitted within 90 days. No tool has been developed specifically in this population to predict readmission or death. Clinicians are unable to identify patients at particular risk, yet resources to prevent readmission are allocated based on clinical judgement. METHODS: In participating hospitals, consecutive admissions of patients with AECOPD were identified by screening wards and reviewing coding records. A tool to predict 90-day readmission or death without readmission was developed in two hospitals (the derivation cohort) and validated in: (a) the same hospitals at a later timeframe (internal validation cohort) and (b) four further UK hospitals (external validation cohort). Performance was compared with ADO, BODEX, CODEX, DOSE and LACE scores. RESULTS: Of 2417 patients, 936 were readmitted or died within 90 days of discharge. The five independent variables in the final model were: Previous admissions, eMRCD score, Age, Right-sided heart failure and Left-sided heart failure (PEARL). The PEARL score was consistently discriminative and accurate with a c-statistic of 0.73, 0.68 and 0.70 in the derivation, internal validation and external validation cohorts. Higher PEARL scores were associated with a shorter time to readmission. CONCLUSIONS: The PEARL score is a simple tool that can effectively stratify patients' risk of 90-day readmission or death, which could help guide readmission avoidance strategies within the clinical and research setting. It is superior to other scores that have been used in this population. TRIAL REGISTRATION NUMBER: UKCRN ID 14214.

Validation of the DECAF score to predict hospital mortality in acute exacerbations of COPD.

BACKGROUND: Hospitalisation due to acute exacerbations of COPD (AECOPD) is common, and subsequent mortality high. The DECAF score was derived for accurate prediction of mortality and risk stratification to inform patient care. We aimed to validate the DECAF score, internally and externally, and to compare its performance to other predictive tools. METHODS: The study took place in the two hospitals within the derivation study (internal validation) and in four additional hospitals (external validation) between January 2012 and May 2014. Consecutive admissions were identified by screening admissions and searching coding records. Admission clinical data, including DECAF indices, and mortality were recorded. The prognostic value of DECAF and other scores were assessed by the area under the receiver operator characteristic (AUROC) curve. RESULTS: In the internal and external validation cohorts, 880 and 845 patients were recruited. Mean age was 73.1 (SD 10.3) years, 54.3% were female, and mean (SD) FEV1 45.5 (18.3) per cent predicted. Overall mortality was 7.7%. The DECAF AUROC curve for inhospital mortality was 0.83 (95% CI 0.78 to 0.87) in the internal cohort and 0.82 (95% CI 0.77 to 0.87) in the external cohort, and was superior to other prognostic scores for inhospital or 30-day mortality. CONCLUSIONS: DECAF is a robust predictor of mortality, using indices routinely available on admission. Its generalisability is supported by consistent strong performance; it can identify low-risk patients (DECAF 0-1) potentially suitable for Hospital at Home or early supported discharge services, and high-risk patients (DECAF 3-6) for escalation planning or appropriate early palliation. TRIAL REGISTRATION NUMBER: UKCRN ID 14214.

Red-emitting protein-coated conjugated polymer nanoparticles.

Red emitting materials are desirable in biology due to the transparency of certain biological tissues at these wavelengths. Here, we report the synthesis of aqueous dispersions of amphiphilic protein (hydrophobin) capped red-emitting cyano-substituted poly(p-phenylenevinylene) conjugated polymer nanoparticles (CPNs) and their use in labeling live mammalian (HeLa) cells.

A mildly relativistic radio jet from the otherwise normal type Ic supernova 2007gr.

The class of type Ic supernovae have drawn increasing attention since 1998 owing to their sparse association (only four so far) with long duration gamma-ray bursts (GRBs). Although both phenomena originate from the core collapse of a massive star, supernovae emit mostly at optical wavelengths, whereas GRBs emit mostly in soft gamma-rays or hard X-rays. Though the GRB central engine generates ultra-relativistic jets, which beam the early emission into a narrow cone, no relativistic outflows have hitherto been found in type Ib/c supernovae explosions, despite theoretical expectations and searches. Here we report radio (interferometric) observations that reveal a mildly relativistic expansion in a nearby type Ic supernova, SN 2007gr. Using two observational epochs 60 days apart, we detect expansion of the source and establish a conservative lower limit for the average apparent expansion velocity of 0.6c. Independently, a second mildly relativistic supernova has been reported. Contrary to the radio data, optical observations of SN 2007gr indicate a typical type Ic supernova with ejecta velocities approximately 6,000 km s(-1), much lower than in GRB-associated supernovae. We conclude that in SN 2007gr a small fraction of the ejecta produced a low-energy mildly relativistic bipolar radio jet, while the bulk of the ejecta were slower and, as shown by optical spectropolarimetry, mildly aspherical.

Evidence against solar influence on nuclear decay constants.

The hypothesis that proximity to the Sun causes variation of decay constants at permille level has been tested and disproved. Repeated activity measurements of mono-radionuclide sources were performed over periods from 200 days up to four decades at 14 laboratories across the globe. Residuals from the exponential nuclear decay curves were inspected for annual oscillations. Systematic deviations from a purely exponential decay curve differ from one data set to another and are attributable to instabilities in the instrumentation and measurement conditions. The most stable activity measurements of alpha, beta-minus, electron capture, and beta-plus decaying sources set an upper limit of 0.0006% to 0.008% to the amplitude of annual oscillations in the decay rate. Oscillations in phase with Earth's orbital distance to the Sun could not be observed within a 10-6 to 10-5 range of precision. There are also no apparent modulations over periods of weeks or months. Consequently, there is no indication of a natural impediment against sub-permille accuracy in half-life determinations, renormalisation of activity to a distant reference date, application of nuclear dating for archaeology, geo- and cosmochronology, nor in establishing the SI unit becquerel and seeking international equivalence of activity standards.

Employment in adults with cystic fibrosis.

BACKGROUND: Chronic ill-health may significantly impact on an individual's ability to work. This not only relates to disease severity but also to psychosocial factors such as illness perception and coping strategies. AIMS: To explore the factors associated with employment status in adults with cystic fibrosis (CF). METHODS: Subjects recruited from adult CF clinics in Aberdeen, Birmingham and Newcastle completed questionnaires assessing health-related quality of life (HRQoL), workplace productivity (presenteeism) and employment. Clinical data indicative of disease severity were also recorded. RESULTS: A total of 254 subjects were recruited, 41 from Aberdeen, 63 from Birmingham and 150 from Newcastle. Sixty-five per cent of subjects were in employment or education. If employed/self-employed, median hours worked was 37.3h/week. Forty per cent reported stopping a job due to CF; 47% felt CF had affected career choice and 24% changed duties because of CF. Ten per cent had taken a pay cut and 23% reported workplace discrimination due to CF. Multivariate modelling demonstrated that employment status was independently associated with educational attainment, centre and the HRQoL domains of role and health perception and is independent of clinical parameters of disease severity. CONCLUSIONS: Adults with CF reported that CF impacted on their ability to work. Employment appeared to be most strongly associated with educational attainment, locality and HRQoL domains and not clinical parameters of severity. Specific guidance is needed for both adults with CF and potential employers, with appropriate targeted interventions aimed at improving health perceptions and coping strategies.

The impact of dietary calcium intake and vitamin D status on the effects of zoledronate.

UNLABELLED: We investigated whether baseline dietary calcium intake or vitamin D status modified the effects of zoledronate. Neither variable influenced the effect of zoledronate on bone mineral density, bone turnover, or risk of acute phase reaction, suggesting that co-administration of calcium and vitamin D supplements with zoledronate may not always be necessary. INTRODUCTION: Calcium and vitamin D supplements are often co-administered with bisphosphonates, but it is unclear whether they are necessary for therapeutic efficacy or minimizing side effects of bisphosphonates. We investigated whether baseline dietary calcium intake or vitamin D status modified the effect of zoledronate on bone mineral density (BMD) or bone turnover at 1 year, or the risk of acute phase reactions (APR). METHODS: Data were pooled from two trials of zoledronate in postmenopausal women without vitamin D deficiency in which calcium and vitamin D were not routinely administered. The cohort (zoledronate n = 154, placebo n = 68) was divided into subgroups by baseline dietary calcium intake (<800 vs. ≥800 mg/day) and vitamin D status [25-hydroxyvitamin D (25OHD) <50 vs. ≥50 nmol/L, and <75 nmol/L vs. ≥75 nmol/L] and treatment × subgroup interactions tested. RESULTS: There were 52, 86, and 36 % of the zoledronate group and 64, 94, and 46 % of the placebo group that had dietary calcium intake ≥800 mg/day, 25OHD ≥50 nmol/L, and 25OHD ≥75 nmol/L, respectively. There were no significant interactions between treatment and either baseline dietary calcium or baseline vitamin D status for lumbar spine BMD, total hip BMD, the bone turnover markers P1NP and ß-CTx, or the risk of an APR. There was also no three-way interaction between baseline dietary calcium intake, baseline vitamin D status, and treatment for any of these variables. CONCLUSIONS: Baseline dietary calcium intake and vitamin D status did not alter the effects of zoledronate, suggesting that co-administration of calcium and vitamin D with zoledronate may not be necessary for individuals not at risk of marked vitamin D deficiency.

Dyspnoea severity and pneumonia as predictors of in-hospital mortality and early readmission in acute exacerbations of COPD.

BACKGROUND: Rates of mortality and readmission are high in patients hospitalised with acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In this population, the prognostic value of the Medical Research Council Dyspnoea Scale (MRCD) is uncertain, and an extended MRCD (eMRCD) scale has been proposed to improve its utility. Coexistent pneumonia is common and, although the CURB-65 prediction tool is used, its discriminatory value has not been reported. METHODS: Clinical and demographic data were collected on consecutive patients hospitalised with AECOPD. The relationship of stable-state dyspnoea severity to in-hospital mortality and 28-day readmission was assessed. The discriminatory value of CURB-65, MRCD and eMRCD, in the prediction of in-hospital mortality, was assessed and compared. RESULTS: 920 patients were recruited. 10.4% died in-hospital and 19.1% of the 824 survivors were readmitted within 28 days of discharge. During their stable state prior to admission, 34.2% of patients were too breathless to leave the house. Mortality was significantly higher in pneumonic than in non-pneumonic exacerbations (20.1% vs 5.8%, p<0.001). eMRCD was a significantly better discriminator than either CURB-65 or the traditional MRCD scale for predicting in-hospital mortality, and was a stronger prognostic tool than CURB-65 in the subgroup of patients with pneumonic AECOPD. CONCLUSIONS: The severity of dyspnoea in the stable state predicts important clinical outcomes in patients hospitalised with AECOPD. The eMRCD scale identifies a subgroup of patients at a particularly high risk of in-hospital mortality and is a better predictor of mortality risk than CURB-65 in exacerbations complicated by pneumonia.

Volatile biomarkers of Pseudomonas aeruginosa in cystic fibrosis and noncystic fibrosis bronchiectasis.

AIMS: The purpose of this study was to determine whether volatile organic compounds specific to Pseudomonas aeruginosa could be detected in clinical sputum specimens. METHODS AND RESULTS: Patients were recruited from specialist bronchiectasis and cystic fibrosis clinics. The gold standard for diagnosing Ps. aeruginosa infection was a positive sputum culture. About 72 sputum headspace samples taken from patients at risk of or known to have prior Ps. aeruginosa infection were analysed by solid phase micro-extraction mass spectrometry. 2-nonanone was a marker in Ps. aeruginosa in sputum headspace gas with sensitivity of 72% and specificity of 88%. A combination of volatile compounds, a sputum library of 17 compounds with 2-nonanone, increased sensitivity in the detection of Ps. aeruginosa to 91% with specificity of 88%. CONCLUSIONS: In contrast to the 48-hour turnaround for classical microbiological culture, these results were available within 1-2 h. These data demonstrate the potential for rapid and accurate diagnosis of Ps. aeruginosa infection from sputum samples. SIGNIFICANCE AND IMPACT OF THE STUDY: 2-Nonanone is a compound requiring further study in the exhaled breath as it may improve diagnostic of Ps. aeruginosa infection when combined with other reported volatile markers.

Cost-Effectiveness of Dementia Prevention Interventions.

BACKGROUND: Assessment of cost-effectiveness of interventions to address modifiable risk factors associated with dementia requires estimates of long-term impacts of these interventions which are rarely directly available and must be estimated using a range of assumptions. OBJECTIVES: To test the cost-effectiveness of dementia prevention measures using a methodology which transparently addresses the many assumptions required to use data from short-term studies, and which readily incorporates sensitivity analyses. DESIGN: We explore an approach to estimating cost-effective prices which uses aggregate data including estimated lifetime costs of dementia, both financial and quality of life, and incorporates a range of assumptions regarding sustainability of short- term gains and other parameters. SETTING: The approach is addressed in the context of the theoretical reduction in a range of risk factors, and in the context of a specific small-scale trial of an internet-based intervention augmented with diet and physical activity consultations. MEASUREMENTS: The principal outcomes were prices per unit of interventions at which interventions were cost-effective or cost-saving. RESULTS: Taking a societal perspective, a notional intervention reducing a range of dementia risk-factors by 5% was cost-effective at $A460 per person with higher risk groups at $2,148 per person. The on-line program costing $825 per person was cost-effective at $1,850 per person even if program effect diminished by 75% over time. CONCLUSIONS: Interventions to address risk factors for dementia are likely to be cost-effective if appropriately designed, but confirmation of this conclusion requires longer term follow-up of trials to measure the impact and sustainability of short-term gains.

Effect of portable noninvasive ventilation on thoracoabdominal volumes in recovery from intermittent exercise in patients with COPD.

We previously showed that use of portable noninvasive ventilation (pNIV) during recovery periods within intermittent exercise improved breathlessness and exercise tolerance in patients with COPD compared with pursed-lip breathing (PLB). However, in a minority of patients recovery from dynamic hyperinflation (DH) was better with PLB, based on inspiratory capacity. We further explored this using Optoelectronic Plethysmography to assess total and compartmental thoracoabdominal volumes. Fourteen patients with COPD (means ± SD) (FEV1: 55% ± 22% predicted) underwent, in a balanced order sequence, two intermittent exercise protocols on the cycle ergometer consisting of five repeated 2-min exercise bouts at 80% peak capacity, separated by 2-min recovery periods, with application of pNIV or PLB in the 5 min of recovery. Our findings identified seven patients showing recovery in DH with pNIV (DH responders) whereas seven showed similar or better recovery in DH with PLB. When pNIV was applied, DH responders compared with DH nonresponders exhibited greater tidal volume (by 0.8 ± 0.3 L, P = 0.015), inspiratory flow rate (by 0.6 ± 0.5 L/s, P = 0.049), prolonged expiratory time (by 0.6 ± 0.5 s, P = 0.006), and duty cycle (by 0.7 ± 0.6 s, P = 0.007). DH responders showed a reduction in end-expiratory thoracoabdominal DH (by 265 ± 633 mL) predominantly driven by reduction in the abdominal compartment (by 210 ± 494 mL); this effectively offset end-inspiratory rib-cage DH. Compared with DH nonresponders, DH responders had significantly greater body mass index (BMI) by 8.4 ± 3.2 kg/m2, P = 0.022 and tended toward less severe resting hyperinflation by 0.3 ± 0.3 L. Patients with COPD who mitigate end-expiratory rib-cage DH by expiratory abdominal muscle recruitment benefit from pNIV application.NEW & NOTEWORTHY Compared with the pursed-lip breathing technique, acute application of portable noninvasive ventilation during recovery from intermittent exercise improved end-expiratory thoracoabdominal dynamic hyperinflation (DH) in 50% of patients with COPD (DH responders). DH responders, compared with DH nonresponders, exhibited a reduction in end-expiratory thoracoabdominal DH predominantly driven by the abdominal compartment that effectively offset end-expiratory rib cage DH. The essential difference between DH responders and DH nonresponders was, therefore, in the behavior of the abdomen.

Ionic currents in intimal cultured synoviocytes from the rabbit.

Hyaluronan, a joint lubricant and regulator of synovial fluid content, is secreted by fibroblast-like synoviocytes lining the joint cavity, and secretion is greatly stimulated by Ca(2+)-dependent protein kinase C. This study aimed to define synoviocyte membrane currents and channels that may influence synoviocyte Ca(2+) dynamics. Resting membrane potential ranged from -30 mV to -66 mV (mean -45 ± 8.60 mV, n = 40). Input resistance ranged from 0.54 GΩ to 2.6 GΩ (mean 1.28 ± 0.57 GΩ; ν = 33). Cell capacitance averaged 97.97 ± 5.93 pF. Voltage clamp using C(s+) pipette solution yielded a transient inward current that disappeared in Ca(2+)-free solutions and was blocked by 1 µM nifedipine, indicating an L-type calcium current. The current was increased fourfold by the calcium channel activator FPL 64176 (300 nM). Using K(+) pipette solution, depolarizing steps positive to -40 mV evoked an outward current that showed kinetics and voltage dependence of activation and inactivation typical of the delayed rectifier potassium current. This was blocked by the nonspecific delayed rectifier blocker 4-aminopyridine. The synoviocytes expressed mRNA for four Kv1 subtypes (Kv1.1, Kv1.4, Kv1.5, and Kv1.6). Correolide (1 µM), margatoxin (100 nM), and α-dendrotoxin block these Kv1 subtypes, and all of these drugs significantly reduced synoviocyte outward current. The current was blocked most effectively by 50 nM κ-dendrotoxin, which is specific for channels containing a Kv1.1 subunit, indicating that Kv1.1 is critical, either as a homomultimeric channel or as a component of a heteromultimeric Kv1 channel. When 50 nM κ-dendrotoxin was added to current-clamped synoviocytes, the cells depolarized by >20 mV and this was accompanied by an increase in intracellular calcium concentration. Similarly, depolarization of the cells with high external potassium solution caused an increase in intracellular calcium, and this effect was greatly reduced by 1 µM nifedipine. In conclusion, fibroblast-like synoviocytes cultured from the inner synovium of the rabbit exhibit voltage-dependent inward and outward currents, including Ca(2+) currents. They thus express ion channels regulating membrane Ca(2+) permeability and electrochemical gradient. Since Ca(2+)-dependent kinases are major regulators of synovial hyaluronan secretion, the synoviocyte ion channels are likely to be important in the regulation of hyaluronan secretion.

Assessment of sample handling practices on microbial activity in sputum samples from patients with cystic fibrosis.

AIM: The aim of this study was to quantitatively and qualitatively assess the effect of sample storage on the metabolically active microbial community found in sputum samples from patients with cystic fibrosis (CF). METHODS: Sputum samples were collected and split in two equal aliquots one of which was immersed in RNAlater and refrigerated immediately, the second stored at room temperature for 24 h and RNAlater was subsequently added. mRNA was extracted, and RT-PCR-DGGE and qPCR analysis of the bacterial and fungal communities was carried out. RESULTS: Significant differences in the bacterial communities between the two protocols were observed but there were no significant difference seen in the fungal community analyses. Analysis by qPCR demonstrated that room temperature storage gave statistically significant increases in eubacteria and Pseudomonas spp. and a statistically significant decrease in those of Haemophilus influenzae. CONCLUSIONS: The analysis of metabolically active microbial communities from CF sputum using molecular techniques indicated that samples should be stored at 4 degrees C upon addition of RNAlater to obtain an accurate depiction of the CF lung microbiota. Also, storing respiratory samples at room temperature may cause an over representation of Pseudomonas aeruginosa and mask the presence of other clinically significant organisms.