Standardization of isothermal microcalorimetry in urinary tract infection detection by using artificial urine

Purpose: Isothermal microcalorimetry (IMC) has recently been reported as a new method to rapidly detect urinary tract pathogens (UTP). However, further application of microcalorimetry in the clinical setting requires a standardized procedure. An important step toward such standardization is to use a reproducible growth medium. In this study, we investigated the potential of artificial urine in combination with microcalorimetry for detection of common UTP. Methods: A microcalorimeter equipped with 48 channels was used. Detection was accomplished, and growth was monitored for four bacterial strains in artificial urine at 37°C by measuring metabolic heat flow (μW=μJ/s) as a function of time. The strains were Escherichia coli, Proteus mirabilis, Enterococcus faecalis, and Staphylococcus aureus. Result: Bacterial growth was detected after 3-32h with decreasing inoculums down to 1CFU. The gram-negative strains grew and were detected faster than their gram-positive counterparts. The growth rates the different strains were 0.75±0.11 for E. coli, 0.74±0.10 for E. faecalis, 1.31±0.04 for P. mirabilis, and 0.56±0.20 for S. aureus. The shape of individual heat flow curves was characteristic for each species independent of its initial concentration. Conclusions: IMC allows rapid detection of UTP in artificial urine. Clearly, different heat flow patterns enable accurate pathogen differentiation. UTP detection after only 4h is realistic. The rapid detection of UTP tested in standardized artificial urine proves the diagnostic potential of IMC and warrants further microcalorimetric studies in the clinical setting of urinary tract infection

Microbial biofilm formation and catheter-associated bacteriuria in patients with suprapubic catheterisation

Purpose: Catheter-associated bacteriuria (CAB) with transurethral catheters is almost inevitable. Suprapubic catheters (SPCs) are widely considered to decrease the risk of CAB. However, SPCs are implants similarly prone to microbial biofilm formation. The spectrum of colonising pathogens has not been investigated. The aim of this prospective study was: (1) to assess the diversity of microbial suprapubic catheter colonisation (MSPCC), (2) to identify risk factors and (3) to investigate its association with CAB and catheter-associated urinary tract infection (CA-UTI). Methods: A total of 218 SPCs from 112 patients were studied. Urine specimens were obtained after device replacement or removal. Sonication was performed to dislodge adherent microorganisms. Data of patient sex, age, indwelling time, and underlying disease were recorded. Results: Sonicate-fluid culture (SFC) detected MSPCC in 95%. Increasing indwelling time correlated with MSPCC (p<0.05). Negative SFC was more frequent when antibiotic prophylaxis was applied at time of catheter placement (15 vs. 2%, p<0.05). Most commonly isolated were Enterobacteriaceae (45.8%), followed by Enterococcus spp. (25.7%) and Pseudomonas aeruginosa (10.3%). CAB and CA-UTI were observed in 95 and 11%, respectively. Conclusions: This study provides the first analysis of MSPCC. Indwelling time increases, whereas antibiotic prophylaxis decreases the risk of MSPCC. The spectrum of pathogens is comparable to the one obtained from urethral catheter biofilms. Urine specimens could not demonstrate the microbial diversity of MSPCC. SPCs are not preferable to urethral catheters to reduce CAB. Whether the risk of CA-UTI could be minimised by SPCs remains to be clarifie

Comparison of the roll-plate and sonication techniques in the diagnosis of microbial ureteral stent colonisation: results of the first prospective randomised study

Background: Microbial ureteral stent colonisation (MUSC) is one leading risk factor for complications associated with ureteral stent placement. As MUSC remains frequently undetected by standard urine cultures, its definitive diagnosis depends on microbiological investigation of the stent. However, a standard reference laboratory technique for studying MUSC is still lacking. Materials and methods: A total of 271 ureteral stents removed from 199 consecutive patients were investigated. Urine samples were obtained prior to device removal. Stents were divided into four parts. Each part was separately processed by the microbiology laboratory within 6h. Ureteral stents were randomly allocated to roll-plate or sonication, respectively, and analysed using standard microbiological techniques. Demographic and clinical data were prospectively collected using a standard case-report form. Results: Overall, roll-plate showed a higher detection rate of MUSC compared with sonication (35 vs. 28%, p<0.05) and urine culture (35 vs. 8%, p<0.05). No inferiority of Maki's technique was observed even when stents were stratified according to indwelling time below or above 30days. Compared with roll-plate, sonication commonly failed to detect Enterococcus spp., coagulase-negative staphylococci (CoNS) and Enterobacteriaceae. In addition, sonication required more hands-on time, more equipment and higher training than roll-plate in the laboratory. Conclusions: This prospective randomised study demonstrates the superiority of Maki's roll-plate technique over sonication in the diagnosis of MUSC and that urine culture is less sensitive than both methods. The higher detection rate, simplicity and cost-effectiveness render roll-plate the methodology of choice for routine clinical investigation as well as basic laboratory researc

Quantified HI Morphology I: Multi-Wavelengths Analysis of the THINGS Galaxies

Galaxy evolution is driven to a large extent by interactions and mergers with other galaxies and the gas in galaxies is extremely sensitive to the interactions. One method to measure such interactions uses the quantified morphology of galaxy images. Well-established parameters are Concentration, Asymmetry, Smoothness, Gini, and M20 of a galaxy image. Thus far, the application of this technique has mostly been restricted to restframe ultra-violet and optical images. However, with the new radio observatories being commissioned (MeerKAT, ASKAP, EVLA, WSRT/APERTIF, and ultimately SKA), a new window on the neutral atomic hydrogen gas (HI) morphology of a large numbers of galaxies will open up. The quantified morphology of gas disks of spirals can be an alternative indicator of the level and frequency of interaction. The HI in galaxies is typically spatially more extended and more sensitive to low-mass or weak interactions. In this paper, we explore six morphological parameters calculated over the extent of the stellar (optical) disk and the extent of the gas disk for a range of wavelengths spanning UV, Optical, Near- and Far-Infrared and 21 cm (HI) of 28 galaxies from The HI Nearby Galaxy Survey (THINGS). Though the THINGS sample is small and contains only a single ongoing interaction, it spans both non-interacting and post-interacting galaxies with a wealth of multi-wavelength data. We find that the choice of area for the computation of the morphological parameters is less of an issue than the wavelength at which they are measured. The signal of interaction is as good in the HI as in any of the other wavelengths in which morphology has been used to trace the interaction rate to date, mostly star-formation dominated ones (near- and far-ultraviolet). The Asymmetry and M20 parameters are the ones which show the most promise as tracers of interaction in 21 cm line observations.Comment: 16 pages, 11 figure, table 1, accepted by MNRAS, appendix not include

An Observational Estimate for the Mean Secular Evolution Rate in Spiral Galaxies

We have observationally quantified the effect of gravitational torques on stars in disk galaxies due to the stellar distribution itself and explored whether these torques are efficient at transporting angular momentum within a Hubble Time. We derive instantaneous torque maps for a sample of 24 spiral galaxies, based on stellar mass maps that were derived using the pixel-by-pixel mass-to-light estimator by Zibetti, Rix and Charlot. In conjunction with an estimate of the rotation velocity, the mass maps allow us to determine the torque-induced instantaneous angular momentum flow across different radii, resulting from the overall stellar distributions for each galaxy in the sample. By stacking the sample, which effectively replaces a time average by an ensemble average, we find that the torques due to the stellar disk act to transport angular momentum outward over much of the disk (within 3 disk scale lengths). The strength of the ensemble-averaged gravitational torques within one disk scale length have a timescale of ~ 4 Gyr for angular momentum redistribution. This study is the first to observationally determine the strength of torque-driven angular momentum flow of stars for a sample of spiral galaxies, providing an important empirical constraint on secular evolution. (abridged)Comment: 24 pages, 18 Figures A high resolution version of this paper can be found at http://www.mpia-hd.mpg.de/~foyle/papers/MN-09-1350-MJ.pd

The Tumultuous Formation of the Hubble Sequence at z > 1 Examined with HST/WFC3 Observations of the Hubble Ultra Deep Field

We examine in this paper a stellar mass selected sample of galaxies at 1 < z < 3 within the Hubble Ultra Deep Field, utilising WFC3 imaging to study the rest-frame optical morphological distribution of galaxies at this epoch. We measure how apparent morphologies (disk, elliptical, peculiar) correlate with physical properties, such as quantitative structure and spectral-types. One primary result is that apparent morphology does not correlate strongly with stellar populations, nor with galaxy structure at this epoch, suggesting a chaotic formation history for Hubble types at z > 1. By using a locally defined definition of disk and elliptical galaxies based on structure and spectral-type, we find no true ellipticals at z > 2, and a fraction of 3.2+/-2.3% at 1.5 < z < 2. Local counterparts of disk galaxies are at a similar level of 7-10%, much lower than the 75% fraction at lower redshifts. We further compare WFC3 images with the rest-frame UV view of galaxies from ACS imaging, showing that galaxies imaged with ACS that appear peculiar often contain an `elliptical' like morphology in WFC3. We show through several simulations that this larger fraction of elliptical-like galaxies is partially due to the courser PSF of WFC3, and that the `elliptical' class very likely includes early-type disks. We also measure the merger history for our sample using CAS parameters, finding a redshift evolution increasing with redshift, and a peak merger fraction of ~30% at z~2 for the most massive galaxies with M_*> 10^{10} M_sol, consistent with previous results from ACS and NICMOS. We compare our results to semi-analytical model results and find a relatively good agreement between our morphological break-down and the predictions. Finally, we argue that the peculiars, ellipticals and peculiar ellipticals have similar properties, suggesting similar formation modes, likely driven by major mergers.Comment: 21 pages, submitted to MNRA

Data and 2D scaling relations for galaxies in Abell 1689: a hint of size evolution at z~0.2

{abridged} We present imaging and spectroscopy of Abell 1689 (z=0.183) from GEMINI/GMOS-N and HST/ACS. We measure integrated photometry from the GMOS g' and r' images (for 531 galaxies) and surface photometry from the HST F625W image (for 43 galaxies) as well as velocities and velocity dispersions from the GMOS spectra (for 71 galaxies). We construct the Kormendy relation (KR), Faber-Jackson relation (FJR) and colour-magnitude relation (CMR) for early-type galaxies in Abell 1689 using this data and compare them to those of the Coma cluster. We measure the intrinsic scatter of the CMR in Abell 1689 to be 0.054 \pm 0.004 mag which places degenerate constraints on the ratio of the assembly timescale to the time available (beta) and the age of the population. Making the assumption that galaxies in Abell 1689 will evolve into those of Coma over an interval of 2.26 Gyr breaks this degeneracy and limits beta to be > 0.6 and the age of the red sequence to be > 5.5 Gyr (formed at z > 0.55). Without corrections for size evolution but accounting for magnitude cuts and selection effects, the KR & FJR are inconsistent and disagree at the 2 sigma level regarding the amount of luminosity evolution in the last 2.26 Gyr. However, after correcting for size evolution the KR & FJR show similar changes in luminosity (0.22 \pm 0.11 mag) that are consistent with the passive evolution of the stellar populations from a single burst of star formation 10.2 \pm 3.3 Gyr ago (z = 1.8+inf-0.9). Thus the changes in the KR, FJR & CMR of Abell 1689 relative to Coma all agree and suggest old galaxy populations with little or no synchronisation in the star formation histories. Furthermore, the weak evidence for size evolution in the cluster environment in the last 2.26 Gyr places interesting constraints on the possible mechanisms at work, favouring harassment or secular processes over merger scenarios.Comment: Accepted for publication in MNRA

Impact of Cold Ischemia Time on Outcomes of Deceased Donor Kidney Transplantation:An Analysis of a National Registry

Background: Cold ischemia time (CIT) is known to impact kidney graft survival rates. We compare the impact of CIT on graft failure and mortality in circulatory death versus brain death donor kidneys and how it relates to donor age.Methods: We used the prospective Dutch Organ Transplantation Registry to include 2153 adult recipients of brain death (n = 1266) and circulatory death (n = 887) donor kidneys after static cold storage from transplants performed between 2005 and 2012. CIT was modeled nonlinearly with splines. Associations and interactions between CIT, donor type, donor age, 5-year (death-censored) graft survival, and mortality were evaluated.Results: The median CIT was 16.2 hours (interquartile range 12.8-20), ranging from 3.4 to 44.7 hours for brain death and 4.7 to 46.6 hours for circulatory death donor kidneys. At &gt;12 hours of CIT, we observed an increased risk of graft failure in kidneys donated after circulatory death versus after brain death. This risk rose significantly at &gt;22 hours of CIT (hazard ratio 1.45; 95% confidence interval, 1.01-2.49; P = 0.043). Kidneys that came from 60-year-old circulatory death donors demonstrated elevated hazard risk at 19 hours of CIT, a shorter timeline than that for kidneys that came from brain death donors of the same age (hazard ratio 1.33; 95% confidence interval, 1.00-1.78; P = 0.045). The additional harmful effects of increased CIT in kidneys from circulatory-death donors were also found for death-censored graft failure but did not affect mortality rates in any significant way.Conclusions: The findings support the hypothesis that prolonged cold ischemia is more harmful for circulatory death donor kidneys that have already been subjected to a permissible period of warm ischemia. Efforts should be made to reduce CIT, especially for older circulatory death donor kidneys.</p

Multi wavelength study of the gravitational lens system RXS J1131-1231: II Lens model and source reconstruction

High angular resolution images of the complex gravitational lens system RXS J1131-1231 (a quadruply imaged AGN with a bright Einstein ring) obtained with the Advanced Camera for Surveys and NICMOS instruments onboard the Hubble Space Telescope are analysed to determine the lens model and to reconstruct the host galaxy. Results: 1- Precise astrometry and photometry of the four QSO lensed images (A-D) and of the lensing galaxy (G) are obtained. They are found in agreement with an independent study presented in a companion paper. The position and colours of the X object seen in projection close to the lens are found to be only compatible with a satellite galaxy associated with the lens. 2- The Singular Isothermal Ellipsoid plus external shear provides a good fit of the astrometry of images A-D. The positions of extended substructures are also well reproduced. However an octupole (m=4) must be added to the lens potential in order to reproduce the observed lens position, as well as the IB/IC point-like image flux ratio. The ellipticity and orientation of the mass quadrupole are found similar to those of the light distribution, fitted by a Sersic profile. The lens (z=0.295) is found to be a massive elliptical in a rich environment and showing possible evolution with respect to z=0. 3- The host galaxy (z=0.658) is found to be a substantially magnified (M ~ 9) luminous Seyfert 1 spiral galaxy. The angular resolution is sufficient to see regions where stars are intensively forming. Interaction with a closeby companion is also observed. 4- Finally, in the case of RXS J1131-1231, extended lensed structures do not help much in constraining the lens model.Comment: 17 pages, 6 figures, accepted in Astronomy and Astrophysics; improved Latex processing. Version with full resolution figures available at http://www.astro.ulg.ac.be/~claesken/lens1131_II.pd

Criteria for and Appropriateness of Renal Transplantation in Elderly Patients With End-Stage Renal Disease : A Literature Review and Position Statement on Behalf of the European Renal Association-European Dialysis and Transplant Association Descartes Working Group and European Renal Best Practice

During the last 20 years, waiting lists for renal transplantation (RT) have grown significantly older. However, elderly patients (ie ≥65 years of age) are still more rarely referred or accepted to waiting lists and, if enlisted, have less chances of actually receiving a kidney allograft, than younger counterparts. In this review, we looked at evidence for the benefits and risks of RT in the elderly trying to answer the following questions: Should RT be advocated for elderly patients? What should be the criteria to accept elderly patients on the waiting list for RT? What strategies might be used to increase the rate of RT in waitlisted elderly candidates? For selected elderly patients, RT was shown to be superior to dialysis in terms of patient survival. Virtually all guidelines recommend that patients should not be deemed ineligible for RT based on age alone, although a short life expectancy generally might preclude RT. Concerning the assessment of comorbidities in the elderly, special attention should be paid to cardiac evaluation and screening for malignancy. Comorbidity scores and frailty assessment scales might help the decision making on eligibility. Psychosocial issues should also be evaluated. To overcome the scarcity of organ donors, elderly RT candidates should be encouraged to consider expanded criteria donors and living donors, as alternatives to deceased standard criteria donors. It has been demonstrated that expanded criteria donor RT in patients 60 years or older is associated with higher survival rates than remaining on dialysis, whereas living donor RT is superior to all other options.Peer reviewe