733 research outputs found

    Evaluation of house price models using an ECM approach: The case of the Netherlands

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    Evaluation of house price models using an ECM approach: The case of the Netherlands

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    Este estudo apresenta uma abordagem raramente discutida no âmbito das finanças públicas, expondo a ideia de que o processo de endividamento é composto por um fator permanente e outro transitório. Com isso, o objetivo émensurar a parte permanente e a parte transitória do endividamento dos municípios brasileiros nos anos de 1989 a 2012. Para isso, é utilizado um método que pode ser aplicado em séries não estacionárias e não lineares, chamado de decomposição em modos empíricos. Os resultados indicam que a composição do processo de endividamento dos municípios é, em grande parte, formada pelo fator transitório da dívida, em outras palavras, os governos municipais vêm expandindo suas dívidas de modo geral em seus respectivos ciclos orçamentários.This study presents an approach rarely discussed in the ambit of public finances,exposing the idea that the process of indebtedness is composed by permanent and transitoryfactors. With this, the objective was to measure the permanent part and the transitory partof the indebtedness of Brazilian municipalities in the years 1989 to 2012. For this, a methodthat can be applied in non-stationary and non-linear series is called Decomposition inEmpirical Modes. The results indicate that the composition of the process of indebtednessof the municipalities is largely formed by the transitory factor of the debt, in other words,the municipal governments have been expanding their debts generally in their respectivebudgets cycles

    The canine chronic atrioventricular block model in cardiovascular preclinical drug research

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    Ventricular cardiac arrhythmia is a life threating condition arising from abnormal functioning of many factors in concert. Animal models mirroring human electrophysiology are essential to predict and understand the rare pro- and anti-arrhythmic effects of drugs. This is very well accomplished by the canine chronic atrioventricular block (CAVB) model. Here we summarize canine models for cardiovascular research, and describe the development of the CAVB model from its beginning. Understanding of the structural, contractile and electrical remodelling processes following atrioventricular (AV) block provides insight in the many factors contributing to drug-induced arrhythmia. We also review all safety pharmacology studies, efficacy and mechanistic studies on anti-arrhythmic drugs in CAVB dogs. Finally, we compare pros and cons with other in vivo preclinical animal models. In view of the tremendous amount of data obtained over the last 100 years from the CAVB dog model, it can be considered as man's best friend in preclinical drug research. LINKED ARTICLES: This article is part of a themed issue on Preclinical Models for Cardiovascular disease research (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.5/issuetoc

    Late Na+Current Inhibition by Ranolazine Reduces Torsades de Pointes in the Chronic Atrioventricular Block Dog Model

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    ObjectivesThis study investigated whether ranolazine reduces dofetilide-induced torsades de pointes (TdP) in a model of long QT syndrome with down-regulated K+currents due to hypertrophic remodeling in the dog with chronic atrioventricular block (cAVB).BackgroundRanolazine inhibits the late Na+current (INaL) and is effective against arrhythmias in long QT3 syndromes despite its blocking properties of the rapid component of delayed rectifying potassium current.MethodsRanolazine was administered to cAVB dogs before or after TdP induction with dofetilide and electrophysiological parameters were determined including beat-to-beat variability of repolarization (BVR). In single ventricular myocytes, effects of ranolazine were studied on INaL, action potential duration, and dofetilide-induced BVR and early afterdepolarizations.ResultsAfter dofetilide, ranolazine reduced the number of TdP episodes from 10 ± 3 to 3 ± 1 (p < 0.05) and partially reversed the increase of BVR with no abbreviation of the dofetilide-induced QT prolongation. Likewise, pre-treatment with ranolazine, or using lidocaine as a specific Na+channel blocker, attenuated TdP, but failed to prevent dofetilide-induced increases in QT, BVR, and ectopic activity. In cAVB myocytes, ranolazine suppressed dofetilide-induced early afterdepolarizations in 25% of cells at 5 μmol/l, in 75% at 10 μmol/l, and in 100% at 15 μmol/l. At 5 μmol/l, ranolazine blocked 26 ± 3% of tetrodotoxin-sensitive INaL, and 49 ± 3% at 15 μmol/l. Despite a 54% reduction of INaLamplitude in cAVB compared with control cells, INaLinhibition by 5 μmol/l tetrodotoxin equally shortened relative action potential duration and completely abolished dofetilide-induced early afterdepolarizations.ConclusionsDespite down-regulation of INaLin remodeled cAVB hearts, ranolazine is antiarrhythmic against drug-induced TdP. The antiarrhythmic effects are reflected in concomitant changes of BVR

    High-Septal Pacing Reduces Ventricular Electrical Remodeling and Proarrhythmia in Chronic Atrioventricular Block Dogs

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    ObjectivesThis study was designed to analyze the relevance of ventricular activation patterns for ventricular electrical remodeling after atrioventricular (AV) block in dogs.BackgroundBradycardia is thought to be the main contributor to ventricular electrical remodeling after complete AV block. However, an altered ventricular activation pattern or AV dyssynchrony may also contribute.MethodsFor 4 weeks, AV block dogs were either paced from the high-ventricular septum near the His bundle at lowest captured rate (n = 9, high-septal pacing [HSP]) or kept at idioventricular rate without controlled activation (n = 14, chronic AV block [CAVB]). Multiple electrocardiographic and electrophysiological parameters were measured under anesthesia at 0 and 4 weeks. Proarrhythmia was tested at 4 weeks by IKrblock (25 μg/kg dofetilide intravenous).ResultsAt 0 weeks, the 2 groups were comparable, whereas after 4 weeks of similar bradycardia, QT duration at unpaced conditions had increased from 300 ± 5 to 395 ± 18 ms in CAVB (+32 ± 6%) and from 307 ± 8 ms to 357 ± 11 ms in HSP (+17 ± 4%; p < 0.05). Frequency dependency of repolarization was less steep in HSP compared to CAVB dogs after 4 weeks remodeling. Beat-to-beat variability of repolarization, a proarrhythmic parameter, increased only in CAVB from 0 to 4 weeks. Torsades de pointes arrhythmias were induced at 4 weeks in 44% HSP versus 78% CAVB dogs (p = 0.17). Cumulative duration of arrhythmias per inducible dog was 87 ± 36 s in CAVB and 30 ± 21 s in HSP (p < 0.05).ConclusionsHigh-septal pacing reduces the magnitude of ventricular electrical remodeling and proarrhythmia in AV block dogs, suggesting a larger role for altered ventricular activation pattern in the generation of ventricular electrical remodeling than previously assumed

    QT interval variability in body surface ECG: measurement, physiological basis, and clinical value: position statement and consensus guidance endorsed by the European Heart Rhythm Association jointly with the ESCWorking Group on Cardiac Cellular Electrophysiology

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    This consensus guideline discusses the electrocardiographic phenomenon of beat-to-beat QT interval variability (QTV) on surface electrocardiograms. The text covers measurement principles, physiological basis, and clinical value of QTV. Technical considerations include QT interval measurement and the relation between QTV and heart rate variability. Research frontiers of QTV include understanding of QTV physiology, systematic evaluation of the link between QTV and direct measures of neural activity, modelling of the QTV dependence on the variability of other physiological variables, distinction between QTV and general T wave shape variability, and assessing of the QTV utility for guiding therapy. Increased QTV appears to be a risk marker of arrhythmic and cardiovascular death. It remains to be established whether it can guide therapy alone or in combination with other risk factors. QT interval variability has a possible role in non-invasive assessment of tonic sympathetic activity

    Experimental Mapping of the Canine KCNJ2 and KCNJ12 Gene Structures and Functional Analysis of the Canine KIR2.2 ion Channel

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    For many model organisms traditionally in use for cardiac electrophysiological studies, characterization of ion channel genes is lacking. We focused here on two genes encoding the inward rectifier current, KCNJ2 and KCNJ12, in the dog heart. A combination of RT-PCR, 5′-RACE, and 3′-RACE demonstrated the status of KCNJ2 as a two exon gene. The complete open reading frame (ORF) was located on the second exon. One transcription initiation site was mapped. Four differential transcription termination sites were found downstream of two consensus polyadenylation signals. The canine KCNJ12 gene was found to consist of three exons, with its ORF located on the third exon. One transcription initiation and one termination site were found. No alternative splicing was observed in right ventricle or brain cortex. The gene structure of canine KCNJ2 and KCNJ12 was conserved amongst other vertebrates, while current GenBank gene annotation was determined as incomplete. In silico translation of KCN12 revealed a non-conserved glycine rich stretch located near the carboxy-terminus of the KIR2.2 protein. However, no differences were observed when comparing dog with human KIR2.2 protein upon ectopic expression in COS-7 or HEK293 cells with respect to subcellular localization or electrophysiological properties
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