Quercetin, kaempferol and biapigenin fromhypericum perforatum are neuroprotective against excitotoxic insults

In the present study we investigated the effects of phenolic compounds present in Hypericum perforatum against neuronal excitotoxicity and mitochondrial dysfunction. Quercetin, kaempferol and biapigenin significantly reduced neuronal death caused by 100 microM kainate plus 100 microM N-methyl-D-aspartate. The observed neuroprotection was correlated with prevention of delayed calcium deregulation and with the maintenance of mitochondrial transmembrane electric potential. The three compounds were able to reduce mitochondrial lipid peroxidation and loss of mitochondrial transmembrane electric potential caused by oxidative stress induced by ADP plus iron. Moreover, biapigenin was also able to significantly affect mitochondrial bioenergetics and decrease the capacity of mitochondria to accumulate calcium. Taken together, the results suggest that the neuroprotective action induced by quercetin and kaempferol are mainly mediated by antioxidant effects, whereas biapigenin mainly affects mitochondrial bioenergetics and calcium uptake.     

Incidence and Predictors of Permanent Pacemaker Requirement after Transcatheter Aortic Valve Implantation with a Self‐Expanding Bioprosthesis

Background: Previous reports have suggested the occurrence of cardiac conduction disorders and permanent pacemaker (PPM) requirement after transcatheter aortic valve implantation (TAVI). Based on a single‐center experience, we aim to assess the incidence of postprocedural conduction disorders, need for PPM, and its determinants after TAVI with a self‐expanding bioprosthesis. Methods: From August 2007 to October 2009, 32 consecutive patients underwent TAVI with the Medtronic CoreValve (MCV) System (Medtronic Inc., Minneapolis, MN, USA). Three patients paced at baseline and two cases of procedure‐related mortality were excluded. We analyzed the 12‐lead electrocardiogram at baseline, immediately after procedure and at discharge. Requirements for PPM were documented and potential clinical, electrophysiological, echocardiographic, and procedural predictors of PPM requirement were studied. Results: After TAVI, eight patients (29.6%) required PPM implantation due to high‐grade atrioventricular (AV) block. The prevalence of left bundle branch block increased from 13.8% to 57.7% directly after implantation (P = 0.001). Need for PPM was correlated to the depth of prosthesis implantation (r = 0.590; P = 0.001). At a cutoff point of 10.1 mm, the likelihood of pacemaker could be predicted with 87.5% sensitivity and 74% specificity and a receiver operator characteristic curve area of 0.86 ± 0.07 (P = 0.003). Of the seven patients with preexisting right bundle branch block (RBBB), four (57.1%) required PPM implantation after TAVI. Conclusions: High‐grade AV block requiring PPM implantation is a common complication following TAVI and could be predicted by a deeper implantation of the prosthesis. Patients with preexisting RBBB also seem to be at risk for the development of high‐grade AV block and subsequent pacemaker implantation. (PACE 2010; 1364–1372)     

The Validation and Assessment of Machine Learning: A Game of Prediction from High-Dimensional Data

In applied statistics, tools from machine learning are popular for analyzing complex and high-dimensional data. However, few theoretical results are available that could guide to the appropriate machine learning tool in a new application. Initial development of an overall strategy thus often implies that multiple methods are tested and compared on the same set of data. This is particularly difficult in situations that are prone to over-fitting where the number of subjects is low compared to the number of potential predictors. The article presents a game which provides some grounds for conducting a fair model comparison. Each player selects a modeling strategy for predicting individual response from potential predictors. A strictly proper scoring rule, bootstrap cross-validation, and a set of rules are used to make the results obtained with different strategies comparable. To illustrate the ideas, the game is applied to data from the Nugenob Study where the aim is to predict the fat oxidation capacity based on conventional factors and high-dimensional metabolomics data. Three players have chosen to use support vector machines, LASSO, and random forests, respectively.     

Zinc and Vitamin A in Liver of Foetuses and Infants

ABSTRACT. The association of zinc and vitamin A levels was studied in liver of foetuses and infants which were stillborn or died of various causes between the age of 26 weeks of gestation up to 16 weeks post-partum. No correlation between zinc and vitamin A was observed ( r =0.07). Although smaller infants had more hepatic vitamin A than larger infants no significant difference was observed between these groups for liver zinc values.     

Associative processes disorders in schizophrenia

This paper tries to approach and systematize knowledge about the character of associative process disorders in schizophrenia. In considering schizophrenia as an illness composed of various symptoms which may lead to different clinical progress, the paper is mainly focused on disorganization of thinking and, consequently, speaking and communication disorders. Authors reviewed various concept of pathogenesis and course of associative process disorders in schizophrenic patients. Special attention was paid to a connectionist model of disturbed associations. This model originates from cognitive psychology and assumes that concepts are represented as networks in the mental lexicon. Following from this model, a hypothesis was presented, claiming that disturbed associations in schizophrenia may be related to abnormalities in semantic networks. Results of research, supporting this hypothesis, were referred. Moreover, authors tried to describe the relationship between associative processes disorders in schizophrenia and abnormalities in neurophysiological (event--related potentials) and neuropathological (MRI) examinations. At least hypotheses describing the role of neurotransmission disorders was presented.     

Aetiology of chronic suppurative lung disease

Forty one (1%) of 4000 children referred for respiratory disease had chronic suppurative lung disease not due to cystic fibrosis. Further investigations showed congenital malformations in six (15%), primary ciliary dyskinesia syndrome in seven (17%), 11 had immunological abnormalities (27%), and two bronchiectasis due to aspiration (5%). Therefore the underlying cause for the disease was found in 63%. Identification of predisposing causes may facilitate prevention of further bronchial damage.