Only Hyperuricemia with Crystalluria,but not Asymptomatic Hyperuricemia,Drives Progression of Chronic Kidney Disease

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Workflow for Visualization of Neuroimaging Data with an Augmented Reality Device

Commercial availability of three-dimensional (3D) augmented reality (AR) devices has increased interest in using this novel technology for visualizing neuroimaging data. Here, a technical workflow and algorithm for importing 3D surface-based segmentations derived from magnetic resonance imaging data into a head-mounted AR device is presented and illustrated on selected examples: the pial cortical surface of the human brain, fMRI BOLD maps, reconstructed white matter tracts, and a brain network of functional connectivity.     

Mechanical behavior of fixation components for periprosthetic fracture surgery

BackgroundReliable periprosthetic fracture treatment needs detailed knowledge on the mechanical behavior of the fixation components used. The holding capacity of three conventional fixation components for periprosthetic fracture treatment was systematically investigated under different loading directions.MethodsLocking compression plates were fixed to a 7 cm long part of diaphyseal fresh frozen human femur with either a single 1.7 mm cerclage cable, a 5.0 mm monocortical or a bicortical locking screw (n = 5 per group). Constructs were loaded in lateral, torsional and axial direction with respect to the bone axis in a load-to-failure test. Corresponding stress distribution around the screw holes was analyzed by finite element modeling.FindingsBoth screw fixations revealed significantly higher stiffness and ultimate strength in axial compression and torsion compared to the cerclage (all P < 0.01). Ultimate strength in lateral loading and torsion was significantly higher for bicortical screws (mean 3968 N SD 657; mean 28.8 Nm SD 5.9) compared to monocortical screws (mean 2748 N SD 585; mean 14.4 Nm SD 5.7 Nm) and cerclages (mean 3001 N SD 252; mean 3.2 Nm SD 2.0) (P ≤ 0.04). Stress distribution around the screw hole varied according to the screw type and load direction.InterpretationFixation components may be combined according to their individual advantages to achieve an optimal periprosthetic fracture fixation.     

Amiodarone versus sotalol for the treatment of atrial fibrillation after open heart surgery: the Reduction in Postoperative Cardiovascular Arrhythmic Events (REDUCE) trial

Objectives

This prospective, randomized, double-blind, placebo-controlled study compared the efficacy and safety of amiodarone and sotalol in the prevention of atrial fibrillation (AF) following open heart surgery.

Background

The incidence of supraventricular arrhythmias following open heart surgery ranges from 20% to 40%, with AF being the most common. Both amiodarone and sotalol have been shown to be effective in reducing postoperative arrhythmias, but no direct comparison of these agents has been conducted.

Methods

A total of 160 patients were randomized, of whom 134 underwent coronary artery bypass graft surgery (CABG) alone, 17 underwent CABG and concomitant aortic valve replacement surgery (AVR), 9 underwent AVR only, and 1 patient's surgery was canceled. Patients with signs or symptoms of congestive heart failure (CHF), ejection fraction ≤30%, estimated creatinine clearance <30 mL/min, or serum creatinine ≥2.5 mg/dL were excluded. Patients were randomized to receive either sotalol 80 mg 2 times per day (n = 76) or intravenous amiodarone 15 mg/kg over 24 hours followed by oral amiodarone 200 mg 3 times per day (n = 83). Study drug was started at the time of surgery and continued for 7 days or until discharge, whichever came first.

Results

AF occurred in 17% of patients randomized to amiodarone and 25% of the patients randomized to sotalol (P = .21). However, the duration of AF was significantly shorter in amiodarone-treated patients (169 ± 224 min) compared to sotalol treated patients (487 ± 505 min; P = .04). In a subgroup analysis, the incidence of AF in patients undergoing AVR or CABG with AVR was significantly less with amiodarone (1/15, 7%) compared to sotalol (9/11, 82%) (P < .001). Blood pressure was lower immediately after surgery with amiodarone but comparable to sotalol at 24 hours. Of the hemodynamic indices measured, only stroke volume was significantly lower in patients randomized to sotalol at 24 hours (P = .035).

Conclusions

Amiodarone and sotalol share similar efficacy and safety in reducing postoperative AF. Hemodynamic effects were similar between both drugs at 24 hours, with the exception that stroke volume was lower in sotalol-treated patients. In patients undergoing more complex surgery, postoperative AF occurred more frequently with sotalol than with amiodarone.     

Factors associated with poor outcomes in patients with lupus nephritis

The objective of this study was to identify the factors associated with important clinical outcomes in a case-control study of 213 patients with lupus nephritis. Included were 47% Hispanics, 44% African Americans and 9% Caucasians with a mean age of 28 years. Fifty-four (25%) patients reached the primary composite outcome of doubling serum creatinine, end-stage renal disease or death during a mean follow-up of 37 months. Thirty-four percent African Americans, 20% Hispanics and 10% Caucasians reached the primary composite outcome (P < 0.05). Patients reaching the composite outcome had predominantly proliferative lupus nephritis (WHO classes: 30% III, 32% IV, 18% V and 5% II, P < 0.025) with higher activity index score (7 +/- 6 versus 5 +/- 5, P < 0.05), chronicity index (CI) score (4 +/- 3 versus 2 +/- 2 unit, P < 0.025), higher baseline mean arterial pressure (MAP) (111 +/- 21 versus 102 +/- 14 mmHg, P < 0.025) and serum creatinine (1.9 +/- 1.3 versus 1.3 +/- 1.0 mg/dL, P < 0.025), but lower baseline hematocrit (29 +/- 6 versus 31 + 5%, P < 0.025) and complement C3 (54 +/- 26 versus 65 + 33 mg/dL, P < 0.025) compared to controls. More patients reaching the composite outcome had nephrotic range proteinuria compared to controls (74% versus 56%, P < 0.025). By multivariate analysis, CI (hazard ratio [95% CI] 1.18 [1.07-1.30] per point), MAP (HR 1.02 [1.00-1.03] per mmHg), and baseline serum creatinine (HR 1.26 [1.04-1.54] per mg/dL) were independently associated with the composite outcome. We concluded that hypertension and elevated serum creatinine at the time of the kidney biopsy as well as a high CI are associated with an increased the risk for chronic renal failure or death in patients with lupus nephritis.     

Working memory and fear conditioning

Previous studies of associative learning implicate higher-level cognitive processes in some forms of classical conditioning. An ongoing debate is concerned with the extent to which attention and awareness are necessary for trace but not delay eye-blink conditioning [Clark, R. E. & Squire, L. R. (1998) Science 280, 77-81; Lovibond, P. F. & Shanks, D. (2002) J. Exp. Psychol. Anim. Behav. Processes 28, 38-42]. In trace conditioning, a short interval is interposed between the termination of the conditioned stimulus (CS) and the onset of the unconditioned stimulus (US). In delay conditioning, the CS and US overlap. We here investigate the extent to which human classical fear conditioning depends on working memory. Subjects had to carry out an n-back task, requiring tracking an item 1 or 2 back in a sequentially presented list of numbers, while simultaneously being tested for their ability to associate auditory cues with shocks under a variety of conditions (single-cue versus differential; delay versus trace; no task versus 0-, 1-, and 2-back). Differential delay conditioning proved to be more resilient than differential trace conditioning but does show a reduction due to task interference similar in slope to that found in trace conditioning. Explicit knowledge of the stimulus contingency facilitates but does not guarantee trace conditioning. Only the single-cue delay protocol shows conditioning during the more difficult working memory task. Our findings suggest that the larger the cognitive demands on the system, the less likely conditioning occurs. A postexperimental questionnaire showed a positive correlation between conditioning and awareness for differential trace conditioning extinction.