Causes and Risk of Stroke: the Rotterdam Study

It is not easy to imagine that the essence of our being is enclosed in a single organ: the brain. In addition to its miraculous function, also the immensely delicate anatomical and chemical structure of the brain is astounding. In order to maintain its structure and function, the brain needs a constant supply of blood. If the blood flow is interrupted by the occlusion of an artery, the affected part of the brain immediately stops functioning. The brain tissue becomes irreversibly damaged within seconds and the area of irreversible brain damage expands in the course of several hours, resulting in what is called an ischemic stroke (figure 1). A hemorrhagic stroke occurs when blood leaks from an artery into the brain, which has the same detrimental effect on brain tissue as ischemia. Strokes usually take patients completely by surprise. In the normal brain, the input from all of our senses is collected, thoughts and emotions arise, and all voluntary body actions are initiated and coordinated, therefore all these functions can be affected by a stroke. For example, a patient who has a stroke may become unable to utter or understand language, become paralyzed on one side of the body, experience half-sided blindness or difficulties with swallowing, and his or her personality may change dramatically

Voltammetric investigation of the complexation equilibria in the presence of a low level of supporting electrolyte Part 1: Steady-state current-potential curves for inert complexes

The use of microelectrodes for voltammetric investigations of the complexation equilibria at very low concentrations of supporting electrolyte allows the risk of competitive complexation or contamination to be avoided, makes the activities of the species involved closer to their concentrations (which facilitates comparisons with the spectroscopic results) and finally, allows the concentrations of the species to be varied over a broader range. This paper presents the calculations of the steady-state currents for a wide range of complexes that are inert on the experimental time scale, and reports the influence of the concentration of the electroinactive ionic species on the limiting currents. Also, for a number of cases the variation of halfwave potential with the ligand concentration, resulting from changes in the ohmic drop, is given. It is assumed that only one species (the complex or the uncomplexed form) is electroactive; if this is the complex, it may or may not change the number of ligands. The theoretical results were obtained either employing the Myland-Oldham theory extended in this paper or by digital simulation. The results of calculations show that the magnitude of the changes in the steady-state limiting current on complexation depends on the type of complexation equilibrium, the type of the change in the reactant charge number in the electrode process, and the complex formation constant. In a number of situations migrational effects are negligibly small and no special treatment is necessary, despite the lack of supporting electrolyte. In other cases, where migration is significant, the relations between the measured steady-state limiting current and the complex formation constant ß are given in the form of fitted equations that can be used to obtain ß from appropriate experimental data

Analyzing generic and branded substitution patterns in the Netherlands using prescription data

BACKGROUND: As in other societies, pharmaceutical expenditures in the Netherlands are rising every year. As a consequence, needs for cost control are often expressed. One possible solution for cost control could come through increasing generic substitution by pharmacists. We aim to analyse the extent and nature of substitution in recent years and estimate the likelihood of generic or branded substitution in Dutch pharmacies in relation to various characteristics. METHODS: We utilized a linked prescription dataset originating from a general practitioner (GP) and a pharmacy database, both from the northern Netherlands. We selected specific drugs of interest, containing about 55,000 prescriptions from 15 different classes. We used a crossed generalized linear mixed model to estimate the effects that certain patient and pharmacy characteristics as well as timing have on the likelihood that a prescription will eventually be substituted by the pharmacist. RESULTS: Generic substitution occurred at 25% of the branded prescriptions. Generic substitution was more likely to occur earlier in time after patent expiry and to patients that were older and more experienced in their drug use. Individually owned pharmacies had a lower probability of generic substitution compared to chain pharmacies. Oppositely, branded substitution occurred in 10% of generic prescriptions and was positively related to the patients' experience in branded use. Individually owned pharmacies were more likely to substitute a generic drug to a branded compared to other pharmacies. Antidepressant and PPI prescriptions were less prone to generic and more prone to branded substitution. CONCLUSION: Analysis of prescription substitution by the pharmacist revealed strong relations between substitution and patient experience on drug use, pharmacy status and timing. These findings can be utilised to design further strategies to enhance generic substitution

Effect of Anesthesia on Microelectrode Recordings During Deep Brain Stimulation Surgery:A Narrative Review

Deep brain stimulation (DBS) is an effective surgical treatment for patients with various neurological and psychiatric disorders. Clinical improvements rely on careful patient selection and accurate electrode placement. A common method for target localization is intraoperative microelectrode recording (MER). To facilitate MER, DBS surgery is traditionally performed under local or regional anesthesia. However, sedation or general anesthesia is sometimes needed for patients who are unable to tolerate the procedure fully awake because of severe motor symptoms, psychological distress, pain, or other forms of discomfort. The effect of anesthetic drugs on MER is controversial but likely depends on the type and dose of a particular anesthetic agent, underlying disease, and surgical target. In this narrative review, we provide an overview of the current literature on the anesthetic drugs most often used for sedation and anesthesia during DBS surgery, with a focus on their effects on MERs

P363 Assessment of patients with knee or hip osteoarthritis in primary care setting: The arpege survey

Objective: Estimate cost-effectiveness of vaccination against hepatitis A virus (HAV) for children of ethnic minorities in Amsterdam. Background: Pharmaco-economic analysis is relevant for motivating reimbursement of vaccination costs in the framework of a programmatic approach to vaccination of ethnic minorities. Design: Pharmaco-economic modeling. Method: In cost-effectiveness analysis, costs, benefits and health gains were estimated for a large-scale HAV-vaccination for children of Turkish and Maroccan origin. Analysis was performed from the societal perspective, as recommended in the Dutch guidelines for pharmaco-economic research. This implies that indirect costs of production losses are included in the analysis. Cost-effectiveness was expressed in net costs per adult HAV-infection averted in incremental and aggregate analysis. Incremental analysis compares targeted vaccination with the current limited-scale HAV-vaccination that exists, whereas aggregate analysis compares targeted vaccination with the sheer absence of vaccination. Results: Net aggregate costs of targeted HAV-vaccination for Turkish and Maroccan children in Amsterdam amounts to E 61.000. Cost-effectiveness was estimated, in aggregate and incremental analysis, at E 13.500 and 11.100 respectively per adult HAV-infection averted. Uni- and multivariate sensitivity analyses show that major impact on cost-effectiveness may be expected from reductions in the vaccine price through economies of scale. Probabilistic sensitivity analysis indicates possible large fluctuations in cost-effectiveness from I year to another, related to varying incidence of disease. Conclusion: HAV-vaccination for children from ethnic minorities in Amsterdam is not cost saving, but may have a favourable cost-effectiveness. Such a vaccination program fits into the recent Dutch policy of specific vaccinations directed at groups of ethnic minorities, such as for hepatitis B. (C) 2003 Elsevier Ltd. All rights reserved

Betekenis van de land- en tuinbouw voor de welvaart in West-Nederland

De land- en tuinbouw voorziet niet alleen in agrarische producten maar ook in natuur, landschap en cultuurhistorie. In dit onderzoek staat dit brede belang van de land- en tuinbouw in de regio West-Nederland centraal. Uit het onderzoek is naar voren gekomen dat het agrocomplex, waar de land- en tuinbouw deel van uitmaakt, 7,2% van de toegevoegde waarde van West-Nederland genereert, oftewel 10,9 miljard euro. Het aandeel van het agrocomplex in de werkgelegenheid van West-Nederland is 8,2%, oftewel 212.400 arbeidskrachten. Natuur, landschap en cultuurhistorie in agrarische gebieden leveren diverse baten. Deze baten komen veelal terecht bij actorgroepen anders dan de land- en tuinbouwers. Voorbeelden van dergelijke baten zijn een aantrekkelijke woon- en recreatieomgeving. Verder biedt het bollentoerisme, dat sterk gerelateerd is aan de land- en tuinbouwgebieden van de Bollenstreek, werk aan 1.000 arbeidskrachten en een jaarlijkse toegevoegde waarde van minstens 30 miljoen euro. Daarnaast zijn agrarische gebieden belangrijk voor flora en fauna, zoals trek- en weidevogels. Indien de land- en tuinbouw zou verdwijnen, dan heeft dat gevolgen voor al die actorgroepen die op enigerlei wijze zijn verbonden met natuur, landschap en cultuurhistorie in agrarische gebieden

Assessing the feasibility of stationary-phase-assisted modulation for two-dimensional liquid-chromatography separations

Two-dimensional liquid chromatography (2DLC) offers great separation power for complex mixtures. The frequently encountered incompatibility of two orthogonal separation systems, however, makes its application complicated. Active-modulation strategies can reduce such incompatibility issues considerably. Stationary-phase-assisted modulation (SPAM) is the most-common of these techniques, but also the least robust due to the major disadvantage that analytes may elute prematurely. The range of liquid chromatography (LC) applications continues to expand towards ever more complex mixtures. Retention modelling is increasingly indispensable to comprehend and develop LC separations. In this research, a tool was designed to assess the feasibility of applying SPAM in 2DLC. Several parameters were investigated to accurately predict isocratic retention of analytes on trap columns under dilution-flow conditions. Model parameters were derived from scanning-gradient experiments performed on analytical columns. The trap-to-trap repeatability was found to be similar to the prediction error. Dead volumes for the trap columns could not be accurately determined through direct experimentation. Instead, they were extrapolated from dead-volume measurements on analytical columns. Several known retention models were evaluated. Better predictions were found using the quadratic model than with the log-linear (“linear-solvent-strength”) model. Steep scanning gradients were found to result in inaccurate predictions. The impact of the dilution flow on the retention of analytes proved less straightforward than anticipated. Under certain conditions dilution with a weaker eluent was found to be counter productive. A tool was developed to quantify the effect of the dilution flow and to predict whether SPAM could be applied in specific situations. For nine different analytes under 36 different sets of conditions and with three different modulation times, the SPAM tool yielded a correct assessment in more than 95% of all cases (less than 5% false positives plus false negatives)

Objective Evaluation of the Somatogravic Illusion from Flight Data of an Airplane Accident

(1) Background: It is difficult for accident investigators to objectively determine whether spatial disorientation may have contributed to a fatal airplane accident. In this paper, we evaluate three methods to reconstruct the possible occurrence of the somatogravic illusion based on flight data recordings from an airplane accident. (2) Methods: The outputs of two vestibular models were compared with the “standard” method, which uses the unprocessed gravito-inertial acceleration (GIA). (3) Results: All three methods predicted that the changing orientation of the GIA would lead to a somatogravic illusion when no visual references were available. However, the methods were not able to explain the first pitch-down control input by the pilot flying, which may have been triggered by the inadvertent activation of the go-around mode and a corresponding pitch-up moment. Both vestibular models predicted a few seconds delay in the illusory tilt from GIA due to central processing and sensory integration. (4) Conclusions: While it is difficult to determine which method best predicted the somatogravic illusion perceived during the accident without data on the pilot’s pitch perception, both vestibular models go beyond the GIA analysis in taking into account validated vestibular dynamics, and they also account for other vestibular illusions. In that respect, accident investigators would benefit from a unified and validated vestibular model to better explain pilot actions in accidents related to spatial disorientation