F-18-fluorodeoxyglucose positron emission tomography combined with CT in critically ill patients with suspected infection

Contains fulltext : 88623.pdf (publisher's version ) (Closed access)PURPOSE: To assess the value of F-18-fluorodeoxyglucose positron emission tomography (FDG-PET) combined with CT in critically ill patients suspected of having an infection. METHODS: FDG-PET CT scans requested for evaluation of a suspected infection or inflammatory process in critically ill, mechanically ventilated patients were analyzed (blinded for the final clinical diagnosis) and compared with clinical follow-up. RESULTS: Thirty-five FDG-PET/CT scans performed in 33 ICU patients (28 adults and 5 children), median age 58 years (range 1 month-72 years), were analyzed. Twenty-one FDG-PET/CT scans were true positive. Three FDG-PET/CT scans were considered false positive, in one case leading to additional diagnostic procedures (specificity 79%). Additionally, 11 true negatives were found (sensitivity 100%), leading to an overall accuracy of 91%. CONCLUSIONS: FDG-PET/CT scanning is of additional value in the evaluation of suspected infection in critically ill patients in whom conventional diagnostics did not lead to a diagnosis. Apart from the high accuracy, in this study it appeared that, in addition to conventional diagnostic techniques that were routinely performed, a normal FDG-PET/CT ruled out important infections requiring prolonged antibiotic therapy or drainage. Since sensitivity is lower in highly metabolic active tissues (e.g., endocarditis, meningitis), the FDG-PET/CT scan is not suited to detect infections in these tissues.01 maart 201

Hofstadter butterflies of carbon nanotubes: Pseudofractality of the magnetoelectronic spectrum

The electronic spectrum of a two-dimensional square lattice in a perpendicular magnetic field has become known as the Hofstadter butterfly [Hofstadter, Phys. Rev. B 14, 2239 (1976).]. We have calculated quasi-one-dimensional analogs of the Hofstadter butterfly for carbon nanotubes (CNTs). For the case of single-wall CNTs, it is straightforward to implement magnetic fields parallel to the tube axis by means of zone folding in the graphene reciprocal lattice. We have also studied perpendicular magnetic fields which, in contrast to the parallel case, lead to a much richer, pseudofractal spectrum. Moreover, we have investigated magnetic fields piercing double-wall CNTs and found strong signatures of interwall interaction in the resulting Hofstadter butterfly spectrum, which can be understood with the help of a minimal model. Ubiquitous to all perpendicular magnetic field spectra is the presence of cusp catastrophes at specific values of energy and magnetic field. Resolving the density of states along the tube circumference allows recognition of the snake states already predicted for nonuniform magnetic fields in the two-dimensional electron gas. An analytic model of the magnetic spectrum of electrons on a cylindrical surface is used to explain some of the results.Comment: 14 pages, 12 figures update to published versio

Extended preservation and effect of nitric oxide production in liver transplantation

Liver transplantation (Ltx) has become a routine procedure for patients with end-stage liver disease. Despite ongoing progress on short- and long-term graft survival, primary dysfunction (PDF) remains a major problem. PDF is significantly associated with the duration of cold ischemia- and, possibly, with reperfusion-related injury. Nitric oxide (NO) has many physiological functions and plays an important role in modulating tissue injury. However, the mechanism of NO action in ischemia/reperfusion injury after Ltx is thus far unknown. In this study we investigated the role of inducable NO synthase (iNOS) in the liver after preservation with UW solution using the orthotopic Ltx model in the rat. Male Brown Norway rats were used for the Ltx procedure. After donor hepatectomy, livers were stored on ice-cold UW solution for 24 or 40 h and subsequently transplanted. A control group consisted of rats with Ltx after less than 1 h storage. Posttransplant blood samples were taken at 48 h to determine standard parameters for liver injury (aspartate transaminase, lactate dehydrogenase). Liver biopsies were obtained for detection of expression of iNOS (western blot) 24 and 48 h posttransplant. We observed that a preservation time of 24 h in UW solution presents no problem for graft survival after Ltx in rats with some brain function and in healthy animals. After 40 h preservation, liver damage is obvious and graft survival reduced, indicating the limits of cold storage may be within reach. With longer preservation times, more NOs was detected in liver tissue. This finding suggests that NO has a role in ischemia/reperfusion-related injury. Current intervention with NOS inhibitors will reveal whether NO has a negative or a positive effect on graft survival after Ltx.</p

Making big steps in trajectories

We consider the solution of initial value problems within the context of hybrid systems and emphasise the use of high precision approximations (in software for exact real arithmetic). We propose a novel algorithm for the computation of trajectories up to the area where discontinuous jumps appear, applicable for holomorphic flow functions. Examples with a prototypical implementation illustrate that the algorithm might provide results with higher precision than well-known ODE solvers at a similar computation time

Transpulmonary thermodilution cardiac output measurement is not affected by severe pulmonary oedema: a newborn animal study

Editor&apos;s key points † The effect of pulmonary oedema on reliability of transpulmonary thermodilution cardiac output measurement was investigated. † Cardiac output was measured in newborn lambs in the presence of increased extravascular lung water. † Measurement of cardiac output by transpulmonary thermodilution is not affected by severe pulmonary oedema in a newborn lamb model. Background. The transpulmonary thermodilution (TPTD) technique is widely used in clinical practice for measuring cardiac output (CO). This study was designed to investigate the influence of various levels of pulmonary oedema on the reliability of CO measurements by the TPTD method

Dental side effects of long-term obstructive sleep apnea therapy:a 10-year follow-up study

OBJECTIVES: Patients with obstructive sleep apnea (OSA) are usually treated with either mandibular advancement device (MAD) or continuous positive airway pressure (CPAP) therapy. The objective of this study is to evaluate changes in dental occlusion associated with long-term MAD and CPAP therapy. MATERIALS AND METHODS: Data from 14 OSA patients using MAD and 17 OSA patients using CPAP therapy were evaluated at baseline, 2-year and 10-year follow-up. Changes in dental occlusion were analyzed from dental plaster casts with a digital sliding caliper. RESULTS: At 2-year follow-up, MAD therapy resulted in significant dental changes when compared with baseline values. In MAD therapy, overjet and overbite decreased with 1.1 ± 1.8 mm and 1.1 ± 1.2 mm respectively. With CPAP therapy overjet and overbite decreased significantly with 0.2 ± 0.5 mm and 0.3 ± 0.5 mm, respectively. Both groups also showed significant changes in molar occlusion. After a 10-year follow-up, significant and more pronounced changes were seen in overjet and overbite. In MAD therapy, overjet and overbite decreased with 3.5 ± 1.5 mm and 2.9 ± 1.5 mm respectively when compared with baseline values. In CPAP therapy, overjet and overbite decreased with 0.7 ± 1.5 mm and 0.8 ± 1.4 mm respectively when compared with baseline values. CONCLUSIONS: This study demonstrates that MAD and CPAP therapy result in significant changes in dental occlusion. These changes appear progressive and more pronounced with MAD compared to CPAP therapy. CLINICAL RELEVANCE: Long-term OSA treatment results in significant dental side effects that may progress over time. Informed consent is fundamental before starting MAD treatment and individualized long-term follow-up is of eminent importance

Alkaline phosphatase for treatment of sepsis-induced acute kidney injury: a prospective randomized double-blind placebo-controlled trial

Introduction: To evaluate whether alkaline phosphatase (AP) treatment improves renal function in sepsis-induced acute kidney injury (AKI), a prospective, double-blind, randomized, placebo-controlled study in critically ill patients with severe sepsis or septic shock with evidence of AKI was performed.Methods: Thirty-six adult patients with severe sepsis or septic shock according to Systemic Inflammatory Response Syndrome criteria and renal injury defined according to the AKI Network criteria were included. Dialysis intervention was standardized according to Acute Dialysis Quality Initiative consensus. Intravenous infusion of alkaline phosphatase (bolus injection of 67.5 U/kg body weight followed by continuous infusion of 132.5 U/kg/24 h for 48 hours, or placebo) starting within 48 hours of AKI onset and followed up to 28 days post-treatment. The primary outcome variable was progress in renal function variables (endogenous creatinine clearance, requirement and duration of renal replacement therapy, RRT) after 28 days. The secondary outcome variables included changes in circulating inflammatory mediators, urinary excretion of biomarkers of tubular injury, and safety.Results: There was a significant (P = 0.02) difference in favor of AP treatment relative to controls for the primary outcome variable. Individual renal parameters showed that endogenous creatinine clearance (baseline to Day 28) was significantly higher in the treated group relative to placebo (from 50 ± 27 to 108 ± 73 mL/minute (mean ± SEM) for the AP group; and from 40 ± 37 to 65 ± 30 mL/minute for placebo; P = 0.01). Reductions in RRT requirement and duration did not reach significance. The results in renal parameters were supported by significantly more pronounced reductions in the systemic markers C-reactive protein, Interleukin-6, LPS-binding protein and in the urinary excretion of Kidney Injury Molecule-1 and Interleukin-18 in AP-treated patients relative to placebo. The Drug Safety Monitoring Board did not raise any issues throughout the trial.Conclusions: The improvements in renal function suggest alkaline phosphatase is a promising new treatment for patients with severe sepsis or septic shock with AKI.Trial Registration: www.clinicaltrials.gov: NCTNCT00511186. © 2012 Pickkers et al.; licensee BioMed Central Ltd