New diagnostic EEG markers of the Alzheimer’s disease using visibility graph

A new chaos–wavelet approach is presented for electroencephalogram (EEG)-based diagnosis of Alzheimer’s disease (AD) employing a recently developed concept in graph theory, visibility graph (VG). The approach is based on the research ideology that nonlinear features may not reveal differences between AD and control group in the band-limited EEG, but may represent noticeable differences in certain sub-bands. Hence, complexity of EEGs is computed using the VGs of EEGs and EEG sub-bands produced by wavelet decomposition. Two methods are employed for computation of complexity of the VGs: one based on the power of scale-freeness of a graph structure and the other based on the maximum eigenvalue of the adjacency matrix of a graph. Analysis of variation is used for feature selection. Two classifiers are applied to the selected features to distinguish AD and control EEGs: a Radial Basis Function Neural Network (RBFNN) and a two-stage classifier consisting of Principal Component Analysis (PCA) and the RBFNN. After comprehensive statistical studies, effective classification features and mathematical markers were discovered. Finally, using the discovered features and a two-stage classifier (PCA-RBFNN), a high diagnostic accuracy of 97.7% was obtained.     

Distribution of Malassezia species in patients with psoriasis and healthy individuals in Tehran, Iran

Background: Psoriasis is a non‐contagious disorder that affects the skin as red scaly patches. Although the role of Malassezia species in the pathogenesis of psoriasis is still not fully understood, it is thought that these lipophilic yeasts might be a trigger factor in the exacerbation of psoriatic lesions. Methods: Using culture in a specific medium followed by the polymerase chain reaction‐restriction fragment length polymorphism method, the presence of Malassezia species in the skin of 110 patients with psoriasis was compared with that in a control group of 123 healthy patients. Results: The recovery rate of Malassezia species from the skin of patients with psoriasis was significantly lower than that in the controls. In both psoriatic and healthy skin, Malassezia globosa was isolated as the predominant species. In psoriatic patients, the rate of colonization of Malassezia furfur and Malassezia restricta was almost twice that in the controls, whereas M. globosa was isolated more frequently from healthy individuals than from patients. Conclusions: Considering the higher lipase activity secretion by M. furfur in comparison with other Malassezia species, the enzymatic release of arachidonic acid and its metabolites by M. furfur may exacerbate the inflammatory and hyperproliferative changes observed in psoriasis.     

Editor's Choice: Medication-indication knowledge bases: a systematic review and critical appraisal

Objective Medication-indication information is a key part of the information needed for providing decision support for and promoting appropriate use of medications. However, this information is not readily available to end users, and a lot of the resources only contain this information in unstructured form (free text). A number of public knowledge bases (KBs) containing structured medication-indication information have been developed over the years, but a direct comparison of these resources has not yet been conducted.Material and Methods We conducted a systematic review of the literature to identify all medication-indication KBs and critically appraised these resources in terms of their scope as well as their support for complex indication information.Results We identified 7 KBs containing medication-indication data. They notably differed from each other in terms of their scope, coverage for on- or off-label indications, source of information, and choice of terminologies for representing the knowledge. The majority of KBs had issues with granularity of the indications as well as with representing duration of therapy, primary choice of treatment, and comedications or comorbidities.Discussion and Conclusion This is the first study directly comparing public KBs of medication indications. We identified several gaps in the existing resources, which can motivate future research.     

Erythropoietin attenuates motor impairments induced by bilateral renal ischemia/reperfusion in rats

Neurologic sequelae remain a common and destructive problem in patients with acute kidney injury. The objective of this study was to evaluate the possible neuroprotective effect of erythropoietin (EPO) on motor impairments following bilateral renal ischemia (BRI) in two time points after reperfusion: short term (24 h) and long term (1 week). Male Wistar rats underwent BRI or sham surgery. EPO or saline administration was performed 30 min before surgery (1000 U/kg, i.p.). Explorative behaviors and motor function of the rats were evaluated by open field, rotarod, and wire grip tests. Plasma concentrations of blood urea nitrogen (BUN) and creatinine (Cr) were significantly enhanced in BRI rats 24 h after reperfusion. BRI group had only an increased level of BUN but not Cr 1 week after reperfusion. Impairment of balance function by BRI was not reversed by EPO 24 h after reperfusion, but counteracted 7 days after renal ischemia. Muscle strength had no significant differences between the groups. BRI group had a decrease in locomotor activity, and EPO could not reverse this reduction in both time points of the experiment. Although EPO could not be offered as a potential neuroprotective agent in the treatment of motor dysfunctions induced by BRI, it could be effective against balance dysfunction 1 week after renal ischemia.     

Percutaneous implantation of the Edwards SAPIEN™ pulmonic valve: initial results in the first 22 patients

Background

Percutaneous pulmonary valve implantation (PPVI) was introduced in 2000 as an interventional procedure for the treatment of right ventricular outflow tract (RVOT) dysfunction. The new Edwards SAPIEN^? pulmonic valve has reached CE certification at the end of 2010 thus offering an attractive alternative with extended sizes (23 and 26 mm) to the conventional Melody^® valve (sizes 18, 20 and 22 mm).

Patients

Over a 1-year period, PPVI using the Edwards SAPIEN^? pulmonic valve was performed in 22 patients using a standardized procedure. Primary diagnosis was tetralogy of Fallot (n = 11), pulmonary atresia (n = 2), Truncus arteriosus (n = 3), TGA/PS-Rastelli (n = 1), Ross surgery (n = 2), double outlet right ventricle (n = 2) and absent pulmonary valve syndrome (n = 1). The character of the RVOT for PPVI was transannular patch (n = 4), bioprosthesis (n = 2), homograft (n = 5) and Contegra^® conduit (n = 11). The leading hemodynamic problem consisted of a pulmonary stenosis (PS) (n = 2), pulmonary regurgitation (PR) (n = 11) and a combined PS/PR lesion (n = 9).

Results

In 21/22 patients, PPVI was performed successfully (10 × 23 and 11 × 26 mm). There were 9 female and 13 male patients; the mean age was 21.7 years (range 6–83 years), the mean length was 162 cm (range 111–181 cm) and the weight 56.5 kg (range 20–91 kg). Invasive data showed a decrease of RV-systolic pressure from 61.2 mmHg (±23.1) to 41.2 mmHg (±8.6) and reduction of RV–PA gradient from 37.3 mmHg (±23.2) to 6.9 mmHg (±5.3). The PA-systolic pressure increased from 25.8 mmHg (±8.6) to 33.9 mmHg (±9.3) as did the PA diastolic pressure (from 6.0 mmHg (±5.6) to 14.6 mmHg (±4.3). There was a substantial reduction of pulmonary regurgitation from before (none/trivial n = 0, mild n = 2, mode rate n = 9, severe n = 11) to after PPVI (none/trivial n = 20, mild n = 1). During the short-term follow-up of 5.7 months there was no change in the immediate results.

Conclusion

PPVI using the Edwards SAPIEN^? pulmonic valve can be performed safely in a wide range of patients with various diagnoses and underlying pathology of the RVOT and enables the restoration of an adult-size RVOT diameter. Although the immediate and short-term results seem promising, the long-term effects and safety have to be assessed in further clinical follow-up studies.