Syndrome of inappropriate anti-diuresis induces volume-dependent hypercalciuria

Hyponatremia is associated with bone demineralization. We hypothesized that, during hyponatremia, calciuria and calcium balance depend on volemic status. We evaluated calciuria in patients with hyponatremia, secondary to SIAD or hypovolemia. Patients with SIAD exhibited a volemic expansion that was associated with hypercalciuria. Calciuria was proportional to markers of volemia.

INTRODUCTION

Chronic mild hyponatremia has been associated with bone demineralization of unknown mechanisms. During chronic hyponatremia, arginine-vasopressin secretion can result from hypovolemia or from syndrome of inappropriate anti-diuresis (SIAD) that leads to a slightly volemic expansion. Since volemia determines renal calcium excretion and balance, we evaluated calcium homeostasis in patients with chronic hyponatremia, related to SIAD or to hypovolemia.

METHODS

We retrospectively included all patients referred to our Department between May 2006 and May 2014 for hyponatremia, resulting from SIAD or chronic hypovolemia. None had edema, cirrhosis, cardiac, or renal insufficiency. Exploration included estimation of volemia, extracellular fluid volume (ECFV) measurement with inulin, and calcium homeostasis.

RESULTS

In total, the SIAD and hypovolemic groups included 22 and 7 patients, respectively. The SIAD group exhibited signs of increased volemia: higher glomerular filtration rate, higher fractional excretion of uric acid, and lower plasma renin. ECFV exceeded that of the hypovolemic group and was above usual values. There was no difference between the two groups regarding plasma calcium, PTH, and vitamin D. However, in the SIAD group, calciuria was higher than in the hypovolemic group, reaching levels of hypercalciuria. Furthermore, there was a positive correlation between calciuria and markers of volemia.

CONCLUSIONS

Our results show that SIAD results in a volemic expansion tendency that is associated with a decrease in renal calcium reabsorption and thus hypercalciuria, whereas in the hypovolemic group, calciuria was not increased. Therefore, renal loss of calcium and bone demineralization in SIAD patients could be partly induced by volemic expansion.

Rifaximin-resistant Clostridium difficile strains isolated from symptomatic patients

BACKGROUND

Rifaximin has been proposed as an alternative treatment for specific cases of Clostridium difficile infection (CDI) and intestinal decontamination. Rifaximin-resistant C. difficile has occasionally been reported. Antibiotic susceptibility testing relies on anaerobic agar dilution (reference method), which is cumbersome and not routinely used. There is no commercial test for detection of resistance to rifaximin.

OBJECTIVES

To assess resistance to rifaximin by C. difficile and to evaluate the correlation between the results of the rifampicin E-test and susceptibility to rifaximin.

METHODS

We compared the in vitro susceptibility of clinical CDI isolates to rifaximin over a 6-month period using the agar dilution method with susceptibility to rifampicin using the E-test. All isolates were characterized using PCR-ribotyping. Clinical data were recorded prospectively.

RESULTS

We recovered 276 consecutive C. difficile isolates and found that 32.2% of episodes were caused by rifaximin-resistant strains. The MICs for rifaximin ranged from <0.0009-256 mg/L, with a geometric mean (GM) of 0.256 mg/L, an MIC_50/90 of 0.015/>256 mg/L. Rifaximin and rifampicin MICs were comparable, and all strains classed as resistant by agar dilution were correctly classified as resistant by E-test. The most common ribotypes were 001 (37.2%), 078/126 (14.3%), and 014 (12.0%). Ribotype 001 exhibited the highest MICs for rifaximin.

CONCLUSIONS

Resistance to rifaximin was common; resistance rates were higher in ribotype 001 strains. Susceptibility to rifaximin determined by agar dilution correlated with susceptibility to rifampicin determined using the E-test, including rifaximin-resistant strains. Our results suggest that the rifampicin E-test is a valid method for the prediction of rifaximin-resistant C. difficile.

Videofluoroscopic assessment of the pathophysiology of chronic poststroke oropharyngeal dysphagia

BACKGROUND AND PURPOSE

Oropharyngeal dysphagia (OD) is a major complaint following stroke, associated with poor clinical outcome and high mortality rates. We aimed at characterizing the kinematics of swallow response associated with unsafe swallowing in chronic poststroke patients with OD.

PATIENTS AND METHODS

Consecutive poststroke patients with a positive volume-viscosity swallow test for OD 3 months following stroke were studied by videofluoroscopy (VFS). Demographical and clinical factors and kinematics of swallow response were compared between those poststroke patients with safe swallow (penetration-aspiration scale, PAS≤2) and those with unsafe swallow (PAS≥3). Receiver operating characteristic (ROC) curves were drawn for laryngeal vestibule closure (LVC) time which predicts unsafe swallow.

RESULTS

We studied 73 poststroke patients (76.7±9.3 years, 53.4% male) by VFS (60.4% with impaired safety, PAS=4.47±1.44, and 95.9% with impaired efficacy of swallow). Poststroke patients with unsafe swallow presented a poorer functional (Rankin 2.2±1.6 vs 1.2±1.0, P<.012) and nutritional status (MNA-sf≤11, 34.2% vs 7.4%, P<.05) than poststroke patients with safe swallow. Poststroke patients with unsafe swallow presented a significant delay in LVC time (406.4±99.5 ms vs 318.9±80.4 ms; P<.05) and weaker tongue bolus propulsion forces (0.771±0.450 mJ vs 1.638±3.212 mJ; P=.043). LVC time ≥340 ms predicts unsafe swallow in chronic poststroke patients with a diagnostic accuracy of 0.78.

CONCLUSIONS

Impaired safety of swallow in chronic poststroke patients is caused by specific impairments in swallow response including delayed timing of airway protection mechanisms and weak tongue propulsion forces. Treatments aiming to restore swallowing function in poststroke patients with OD should be targeted to improve these critical biomechanical events.

First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process

The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190  GeV/c π^{-} beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3  GeV/c^{2} and 8.5  GeV/c^{2}. Within the experimental uncertainties, the observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of quantum chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. A recent COMPASS SIDIS measurement was obtained at a hard scale comparable to that of these DY results. This opens the way for possible tests of fundamental QCD universality predictions.

Single-dose rituximab in refractory lupus nephritis

BACKGROUND

Off-label use of rituximab in lupus nephritis is reported to be beneficial. While the optimal dose is unknown, the regimen of four intravenous doses of 375 mg/m(2) is commonly employed, despite expense and potential side-effects.

AIM

To investigate the response to single-dose rituximab, added to standard corticosteroids plus additional immunosuppressive agent, in refractory lupus nephritis.

METHODS

Consecutive consenting patients with refractory lupus nephritis despite steroids plus either cyclophosphamide, mycophenolate or azathioprine were enrolled in this ethics-approved, open-label, prospective study. After baseline assessment, patients received one intravenous infusion of 375 mg/m(2) rituximab. Clinical, biochemical and serological (DsDNA, complement) responses to this dose were analysed. Complete renal response (CR) was defined as normalisation of creatinine, albumin, proteinuria and urinary RBCs and partial response (PR) as ≥50% improvement in at least one parameter, without deterioration in others. B-cell depletion was defined as peripheral CD19 lymphocyte count ≤0.05 × 10(9) /L.

RESULTS

Fourteen patients were enrolled in the study. All were B-cell-depleted until 8 months post-dose. Eleven patients (79%) responded (2CR, 9PR) at a median time of 5 months, with a 6-month probability of renal response of 43%. Five patients (45%) relapsed at a median time of 17 months. DsDNA titres decreased in 69%. Side-effects were minimal.

CONCLUSIONS

Single-dose rituximab is effective in relapsed/refractory lupus nephritis. Longevity of B-cell depletion with single-dose rituximab is similar to that of four doses with potentially fewer side-effects.

Encouraging treatment algorithm for computer-assisted navigated total knee arthroplasty (TKA): A retrospective cohort analysis

OBJECTIVE

Navigated computer-assisted total knee arthroplasty (TKA) shows inconclusive mid- to long-term outcome results and is limited by increased costs, surgery-time and an additional learning curve. We introduced a treatment algorithm preserving computer-assisted TKA for patients with adipositas-per-magna, posttraumatic leg-deformities, osteosynthetic material in-situ or reduced preoperative X-ray quality.

METHODS

237 primary unilateral TKA were allocated based on the treatment concept described above. A retrospective pre- and postoperative radiological analysis was performed.

RESULTS

222 TKA (93.7%) were within 3° varus/valgus of mechanical-lower-limb axis (mean absolute deviation: 1.8° ± 1.3°).

CONCLUSION

This algorithm showed an excellent postoperative implantation-accuracy based on an accurate preoperative surgery-planning.

Sickness absence among peer-supported drivers after occupational trauma

Background

Psychological first aid is a common approach for providing support after potentially traumatic events (PTEs). In Germany, a peer support model is recommended by the German Statutory Accident Insurance (DGUV) to reduce sickness absence after occupational accidents, especially in public transportation. However, data on the effectiveness of peer support are very sparse.

Aims

To analyse whether peer support has an impact on sickness absence after work-related traumatic events in public transportation.

Methods

An analysis was conducted in two German public transportation corporations. Due to ethical requirements, we used a historical cohort study comparing peer support by colleagues (VAG-1), peer support at supervisor level (VGF) and a non-intervention group (VAG-0). The study period was from March 2003 to December 2012. We used a negative binominal regression model to estimate the relative risk associated with the interventions and potential confounders.

Results

A total of 259 incident PTEs in employees were observed. A regression analysis identified the severity of PTE (severe and fatal events), VGF and age as significant factors in predicting duration of post-event sickness absence. In a stratified analysis, the mode of peer support (VGF) and age predicted sickness absence for less severe PTEs but this was not significant for severe PTEs.

Conclusions

Severe and fatal PTEs had the strongest impact on sickness absence after PTEs. For less severe PTE, peer support provided by colleagues may be superior to supervisor support.

A community virtual ward model to support older persons with complex health care and social care needs

Background

Globally the older population is increasing rapidly. As a result there is an increase in frail older persons living within the community, with increased risks of a hospital admission and higher mortality and morbidity rates. Due to complexity of care, health care professionals face challenges in providing effective case management and avoiding unplanned admissions to hospital. A community virtual ward (CVW) model was developed to assist health care professionals to support older persons at home during periods of illness and/or functional decline.

Methods

A quantitative observational study was conducted to examine if a CVW model of care reduced unplanned hospital admissions and emergency department (ED) presentations in 54 patients over a 12-month period. The sign-rank test examined matched data on bed days, ED presentations, and unplanned hospital admissions pre- and post-CVW implementation. Other risk factors for admission to hospital were examined using the Mann–Whitney test pre-and post-CVW admission, including falls, living alone, and cognition. Correlations between hospital admission avoidances and unplanned hospital admissions and ED presentations were tested using Spearman’s ρ test.

Results

There was a reduction in ED presentations post-CVW admission (P<0.001), and median unscheduled admissions were reduced (P=0.001). Those living alone had a lower number of ED presentations (median 0.5, interquartile range 0–1) prior to admission in comparison to those living with a caregiver, with no differences observed during admission to CVW. For those who experienced a fall during CVW admission, the odds ratio (OR) of requiring long-term care doubled for each extra fall (OR =2.24, 95% CI 1.11 to 4.52, P=0.025). Reduced cognition was associated with an increased risk of ED presentations (ρ=0.292, P<0.05) but not associated with increased risks of unplanned hospital admissions (ρ=0.09, P=0.546). There were no significant correlations seen between admission avoidance and the number of unplanned hospital admissions or ED presentations.

Conclusion

Through an integrated approach to care, a CVW model in the care of older persons can reduce ED presentations and unplanned hospital admissions.

Expanding conceptualizations of harm reduction: results from a qualitative community-based participatory research study with people who inject drugs

Background

The perspectives of people who use drugs are critical in understanding why people choose to reduce harm in relation to drug use, what practices are considered or preferred in conceptualizations of harm reduction, and which environmental factors interfere with or support the use of harm reduction strategies. This study explores how people who inject drugs (PWID) think about harm reduction and considers the critical imperative of equity in health and social services delivery for this community.

Methods

This community-based participatory research study was conducted in a Canadian urban centre. Using a peer-based recruitment and interviewing strategy, semi-structured qualitative interviews were conducted by and with PWID. The Vidaview Life Story Board, an innovative tool where interviewers and participant co-construct a visual “life-scape” using a board, markers, and customized picture magnets, was used to facilitate the interviews. The topics explored included injection drug use and harm reduction histories, facilitators and barriers to using harm reduction strategies, and suggestions for improving services and supports.

Results

Twenty-three interviews with PWID (14 men and 9 women) were analysed, with a median age of 50. Results highlighted an expanded conceptualization of harm reduction from the perspectives of PWID, including motivations for adopting harm reduction strategies and a description of harm reduction practices that went beyond conventional health-focused concerns. The most common personal practices that PWID used included working toward moderation, employing various cognitive strategies, and engaging in community activities. The importance of social or peer support and improving self-efficacy was also evident. Further, there was a call for less rigid eligibility criteria and procedures in health and social services, and the need to more adequately address the stigmatization of drug users.

Conclusions

These findings demonstrated that PWID incorporate many personal harm reduction practices in their daily lives to improve their well-being, and these practices highlight the importance of agency, self-care, and community building. Health and social services are needed to better support these practices because the many socio-structural barriers this community faces often interfere with harm reduction efforts. Finally, “one size does not fit all” when it comes to harm reduction, and more personalized or de-medicalized conceptualizations are recommended.

Design of catheter radio frequency coils using coaxial transmission line resonators for interventional neurovascular MR imaging

BACKGROUND

It is technically challenging to design compact yet sensitive miniature catheter radio frequency (RF) coils for endovascular interventional MR imaging.

METHODS

In this work, a new design method for catheter RF coils is proposed based on the coaxial transmission line resonator (TLR) technique. Due to its distributed circuit, the TLR catheter coil does not need any lumped capacitors to support its resonance, which simplifies the practical design and construction and provides a straightforward technique for designing miniature catheter-mounted imaging coils that are appropriate for interventional neurovascular procedures. The outer conductor of the TLR serves as an RF shield, which prevents electromagnetic energy loss, and improves coil Q factors. It also minimizes interaction with surrounding tissues and signal losses along the catheter coil. To investigate the technique, a prototype catheter coil was built using the proposed coaxial TLR technique and evaluated with standard RF testing and measurement methods and MR imaging experiments. Numerical simulation was carried out to assess the RF electromagnetic field behavior of the proposed TLR catheter coil and the conventional lumped-element catheter coil.

RESULTS

The proposed TLR catheter coil was successfully tuned to 64 MHz for proton imaging at 1.5 T. B₁ fields were numerically calculated, showing improved magnetic field intensity of the TLR catheter coil over the conventional lumped-element catheter coil. MR images were acquired from a dedicated vascular phantom using the TLR catheter coil and also the system body coil. The TLR catheter coil is able to provide a significant signal-to-noise ratio (SNR) increase (a factor of 200 to 300) over its imaging volume relative to the body coil.

CONCLUSIONS

Catheter imaging RF coil design using the proposed coaxial TLR technique is feasible and advantageous in endovascular interventional MR imaging applications.

How realistic is a racehorse simulator?

Race jockey training is demanding and technical. Increased horse care costs and demands on time have led to greater availability and use of racehorse simulators during training. Little is known about the accuracy of the simulated movement and therefore how effective they are for developing the desired technique. We quantified and compared sacral rotation and displacement vectors for a racehorse simulator and a real galloping horse. A single inertial measurement unit was placed on the sacrum of six horses (horse) during a training gallop along an all-weather seven furlong gallop and on the highest speed setting 'four' on the simulator. Displacements were calculated in all three axes before being cut into cycles and analysed along with roll and pitch. Displacement and rotation amplitudes were extracted and compared for the horse and simulator. Horse sacral movement parameters were more varied than those recorded on the simulator. The real horse exhibited greater dorso-ventral, medio-lateral and roll amplitude but smaller cranio-caudal displacement amplitude and no difference in pitch amplitude. Displacement trajectory of the simulator when viewed laterally from the left side, was anticlockwise, the opposite direction to that of the real horse leaving the regular use of a simulator during jockey training under question. Use of the racehorse simulator is beneficial to develop specific fitness and to enable physical manipulation into the optimal position. Care must be taken to avoid any detrimental effects of training with the opposite movement trajectory to that experienced during a race. The programming of the simulators may benefit from adaptations to maximise their benefits.

Demonstration of Einstein-Podolsky-Rosen Steering Using Single-Photon Path Entanglement and Displacement-Based Detection

We demonstrate the violation of an Einstein-Podolsky-Rosen steering inequality developed for single-photon path entanglement with displacement-based detection. We use a high-rate source of heralded single-photon path-entangled states, combined with high-efficiency superconducting-based detectors, in a scheme that is free of any postselection and thus immune to the detection loophole. This result conclusively demonstrates single-photon entanglement in a one-sided device-independent scenario, and opens the way towards implementations of device-independent quantum technologies within the paradigm of path entanglement.