Application of Electroencephalography to the Study of Cognitive and Brain Functions in Schizophrenia

The electroencephalogram (EEG) recorded from the human scalp is widely used to study cognitive and brain functions in schizophrenia. Current research efforts are primarily devoted to the assessment of event-related potentials (ERPs) and event-related oscillations (EROs), extracted from the ongoing EEG, in patients with schizophrenia and in clinically unaffected individuals who, due to their family history and current mental status, are at high risk for developing schizophrenia. In this article, we discuss the potential usefulness of ERPs and EROs as genetic vulnerability markers, as pathophysiological markers, and as markers of possible ongoing progressive cognitive and cortical deterioration in schizophrenia. Our main purpose is to illustrate that these neurophysiological measures can offer valuable quantitative biological markers of basic pathophysiological mechanisms and cognitive dysfunctions in schizophrenia, yet they may not be specific to current psychiatry's diagnosis and classification. These biological markers can provide unique information on the nature and extent of cognitive and brain dysfunction in schizophrenia. Moreover, they can be utilized to gain deeper theoretical insights into illness etiology and pathophysiology and may lead to improvements in early detection and more effective and targeted treatment of schizophrenia. We conclude by addressing several key methodological, conceptual, and interpretative issues involved in this research field and by suggesting future research directions

Dry friction during sliding of AA1050 on AA2024 at elevated temperature

The friction development between Aluminium AA1050 and Dural AA2024 is studied. Continuous full surface rotational sliding experiments of AA1050 over AA2024 were performed at temperatures between 150 and 350 °C and at contact pressures between 2 and 15 MPa. The required torque was measured as function of rotation angle. A model is set up for the evolution of the friction coefficient, which takes into account temperature, normal pressure and sliding distance. Validation of the model is done by implementation in a finite element program and reproduction of observed behaviour

Lichaamseigen marihuana: inspiratie voor geneesmiddelenonderzoek

Molecular Physiolog

Tandheelkundige radiologie: wet- en regelgeving

Sinds de ontdekking van röntgenstraling is medische beeldvorming een van de belangrijkste toepassingen. In de loop der jaren is door ervaring en wetenschappelijk inzicht de kennis van schadelijke effecten van straling op weefsel aanzienlijk vergroot. Dit heeft geleid tot de International Commission on Radiological Protection (ICRP), de instantie die thans als het gezaghebbendst wordt beschouwd op het gebied van informatie over straling en stralingsbescherming. De stralingswetgeving is in de meeste landen gebaseerd op de 3 uitgangspunten van de ICRP: rechtvaardiging, ALARA en dosislimieten. Voor de Nederlandse situatie is dat deKernenergieweten het Besluit stralingsbescherming. Voor de praktische uitvoering hiervan is de praktijkrichtlijn Radiologie (van de KNMT) beschikbaar. Door te werken volgens de praktijkrichtlijn voldoen tandartsen aan de wettelijke voorschriften, maar nog belangrijker is dat zij dan röntgendiagnostiek kunnen toepassen op een wijze die veilig is voor henzelf, het tandheelkundig team, de patiënten en alle andere bezoekers van de praktijk

The Endocannabinoid Anandamide : Metabolism & Neuroprotection

Marijuana is an extract of the Cannabis sativa and is the most used illegal drug in the world. Public debate centres upon the possible legalization of marijuana for recreational and therapeutic uses. DELTA-exp.9-Tetrahydrocannabinol (THC), the main psychoactive compound in marijuana, exerts its action by binding to G-protein-coupled membrane receptors, i.e. the cannabinoid CB1 and CB2 receptors. The biochemical and pharmacological actions of THC are mimicked by an endogenous lipid termed anandamide [N-arachidonoylethanolamine,5Z,8Z,11Z,14Z-eicosatetraenoyl-N-(2-hydroxyethyl)-amine]. Together with 2-arachidonoylglycerol, anandamide represents a class of endogenous ligands for CB receptors, i.e. the endocannabinoids. The CB receptors, endocannabinoids and proteins for theid biosynthesis and inactivation constitute the endocannabinoid system. The am of the research described in this thesis was to study a) the metabolism of anandamide in human cells and brain tissue, b) the interaction of its oxygenated metabolites with the proteins of the endocannabinoid system, and c) the role of the endocannabinoid system in in vivo neurodegeneration. nchapter 2 of this thesis, we have shown that the life span of anandamide in human brain and cells in culture is limited by a rapid inactivation process consisting of two steps, i.e. a translocation into the cell via a transporter protein, followed by a cleavage by the enzyme fatty acid amide hydrolase [FAAH] (Maccarrone et al., J. Biol. Chem., 1998, 273, 32332-32339). Endocannabinoids are not only inactivated via FAAH, but are also oxygenated by other enzymes such as lipoxygenases. In chapter 3, we have described the synthesis of various oxygenated metabolites of anandamide and 2-AG and characterized their cannabinoid properties (Van der Stelt et al., J. Med. Chem., 2002, 45, 3709-3720) The oxygenated metabolites were shown to competitively inhibit FAAH. Furthermore, depending on the position of the hydroxyl group in the metabolites, they were able to selectively bind to the CB1 or CB2 receptor. The metabolites did not interfere with anandamide uptake into the cell. These results indicate that small changes in the chemical structure of anandamide can lead to the generation of novel compounds which can specifically interact with each of the proteins of the endogenous cannabinoid system. With Molecular Dynamics simulations we have tried to identify the essential structural elements of anandamide, which are necessary for the interaction with the CB1 receptor. The endocannabinoid system is implicated in the regulation of various processes, such as learning, memory, pain and appetite. Its involvement in pathophysiological conditions is less clear, but we have shown in chapters 4, 5 and 6 that THC and anandamide can protect rat brain against neurodegenerative insults in vivo (Van der Stelt et al., J. of Neurosci., 2001, 21, 8765-8771; Van der Stelt et al., J. of Neurosci., 2001, 21, 6475-6479; Van der Stelt et al., Mol. Neurobiol., 2002, in press). We demonstrated that THC and anandamide could significantly reduce the volume of cytotoxic edema in neonatal rats in the acute phase after the intrastriatal injection with the Na+/K+-ATPase inhibitor ouabain. The effect of THC was antagonized by blocking the CB1 receptor with SR141716A, whereas the reduction in cellular swelling by anandamide was insensitive to this CB1 receptor antagonist. After seven days the infarct volume in THC- and anandamide-treated rats was ~40% and ~64%, respectively, smaller compared to control animals. When assessed at this time point, the neuroprotective actions of both anandamide and THC were abolished by SR141716A. A CB1-receptor mediated reduction in calcium influx and a reduced glutamate release are thought to be responsible for the neuroprotection in the hippocampus, striatum and cortex. In summary, the results reported in this thesis indicate that agonists of CB1 receptors might be useful to enhance the neurological outcome after acute brain damage. If the extent of neuronal damage is not too large, inhibitors of endocannabinoid clearance may prove to be suitable leads for drug development, because they have probably limited side effects, e.g. psychotropic activit

Plan de negocio de una empresa de compra y venta de vehículos

Mi objetivo personal a la hora de realizar este proyecto es considerar algún problema o necesidad que exista en la sociedad actualmente, o pueda existir en los próximos años, y tratar de desarrollar una idea de negocio que esté relacionada con ello. En este caso, el problema considerado es la acumulación de vehículos parados, que van a generar las restricciones de tráfico que se están imponiendo debido a los altos niveles de contaminación en las grandes ciudades de los países desarrollados. Se considera que esto generará un decrecimiento del valor de estos vehículos en estos países. Durante el proyecto, se expone este problema, y se desarrollan todos los apartados del plan de negocio, que nos permitirán decidir si es viable o no, ya que este es el objetivo principal del proyecto. La idea principal del negocio, a grandes rasgos, es realizar compras de vehículos en Madrid, para posteriormente venderlos a Nigeria, dado el gran potencial de mercado que existe en el país.Ingeniería en Tecnologías Industriale