Regulation of cardiac microRNAs induced by aerobic exercise training during heart failure

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Multivariate analysis for selecting animals for experimental research

Background Several researchers seek methods for the selection of homogeneous groups of animals in experimental studies, a fact justified because homogeneity is an indispensable prerequisite for casualization of treatments. The lack of robust methods that comply with statistical and biological principles is the reason why researchers use empirical or subjective methods, influencing their results. Objective To develop a multivariate statistical model for the selection of a homogeneous group of animals for experimental research and to elaborate a computational package to use it. Methods The set of echocardiographic data of 115 male Wistar rats with supravalvular aortic stenosis (AoS) was used as an example of model development. Initially, the data were standardized, and became dimensionless. Then, the variance matrix of the set was submitted to principal components analysis (PCA), aiming at reducing the parametric space and at retaining the relevant variability. That technique established a new Cartesian system into which the animals were allocated, and finally the confidence region (ellipsoid) was built for the profile of the animals’ homogeneous responses. The animals located inside the ellipsoid were considered as belonging to the homogeneous batch; those outside the ellipsoid were considered spurious. Results The PCA established eight descriptive axes that represented the accumulated variance of the data set in 88.71%. The allocation of the animals in the new system and the construction of the confidence region revealed six spurious animals as compared to the homogeneous batch of 109 animals. Conclusion The biometric criterion presented proved to be effective, because it considers the animal as a whole, analyzing jointly all parameters measured, in addition to having a small discard rate.

A possible increase of activity of endothelial l-arginine/nitric oxide pathway in aortas of diet-induced obesity rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of chronic stress and high-fat diet on metabolic and nutritional parameters in Wistar rats

Objective: The aim of this study was assess the role of chronic stress on the metabolic and nutritional profile of rats exposed to a high-fat diet. Materials and methods: Thirty-day-old male Wistar rats (70-100 g) were distributed into four groups: normal-diet (NC), chronic stress (St), high-fat diet (HD), and chronic stress/high-fat diet (HD/St). Stress consisted at immobilization during 15 weeks, 5 times per week, 1h per day; and exposure to the high-fat diet lasted 15 weeks. Nutritional and metabolic parameters were assessed. The level of significance was 5%. Results: The HD group had final body weight, total fat, as well as insulin and leptin increased, and they were insulin resistant. The St and HD/St had arterial hypertension and increased levels of corticosterone. Stress blocked the effects of the high-fat diet. Conclusion: Chronic stress prevented the appearance of obesity. Our results help to clarify the mechanisms involved in metabolic and nutritional dysfunction, and contribute to clinical cases linked to stress and high-fat diet.

Aerobic training attenuates nicotinic acethylcholine receptor changes in the diaphragm muscle during heart failure

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Chronic Stress Improves the Myocardial Function without Altering L-type Ca+2 Channel Activity in Rats

Background: Chronic stress is associated with cardiac remodeling; however the mechanisms have yet to be clarified. Objective: The purpose of this study was test the hypothesis that chronic stress promotes cardiac dysfunction associated to L-type calcium Ca2+ channel activity depression. Methods: Thirty-day-old male Wistar rats (70 - 100 g) were distributed into two groups: control (C) and chronic stress (St). The stress was consistently maintained at immobilization during 15 weeks, 5 times per week, 1h per day. The cardiac function was evaluated by left ventricular performance through echocardiography and by ventricular isolated papillary muscle. The myocardial papillary muscle activity was assessed at baseline conditions and with inotropic maneuvers such as: post-rest contraction and increases in extracellular Ca2+ concentration, in presence or absence of specific blockers L-type calcium channels. Results: The stress was characterized for adrenal glands hypertrophy, increase of systemic corticosterone level and arterial hypertension. The chronic stress provided left ventricular hypertrophy. The left ventricular and baseline myocardial function did not change with chronic stress. However, it improved the response of the papillary muscle in relation to positive inotropic stimulation. This function improvement was not associated with the L-type Ca2+ channel. Conclusion: Chronic stress produced cardiac hypertrophy; however, in the study of papillary muscle, the positive inotropic maneuvers potentiated cardiac function in stressed rats, without involvement of L-type Ca2+ channel. Thus, the responsible mechanisms remain unclear with respect to Ca2+ influx alterations. (Arq Bras Cardiol 2012;99(4):907-914)

Gutachten zu den ökologischen Anforderungen an das Inverkehrbringen von Produkten erstattet dem Bundesamt für Umwelt BAFU

Das schweizerische Verfassungsrecht belässt dem Gesetzgeber einen hinreichenden Spielraum, Massnahmen bezüglich der Inverkehrsetzung von importierten Produkten nach Massgabe von Anforderungen an die Produktionsbedingungen im Exportland (Production and Process Methods, PPMs) im Bereich der untersuchten Produkte (Palmöl, Soya, biogene Treibstoffe, Textilien, Baumwolle) im Rahmen eines Bundesgesetzes zu erlassen. Der Gestaltungsspielaum bemisst sich im einzelnen nach den detaillierten Bestimmungen des WTO Rechts. Dabei steht die Förderung freiwilliger Labels und von internationalen Standards für Best Practices im Vordergrund. Es schliesst indessen auch einseitige Import- restriktionen auf Grund von PPMs nicht aus, soweit vorgängig durchgeführte Verhand- lungen mit den Exportstaaten nicht zielführend sind und freiwillige Massnahmen nicht genügen. Das kann vor allem im Rohstoffhandel und im Konzernhandel (intrafirm trade) zutreffen. Die Regelungen unterliegen einer Verhältnismässigkeitsprüfung und sie dürfen sich nicht zum Schutze der einheimischen Industrie auswirken. Das GATT-recht erlaubt auch zollrechtliche Massnahmen als Mittel und Anreiz zur Förderung von Best Practices im Exportstaat. Das Freihandelsabkommen Schweiz-EU folgt den gleichen Grundsätzen, schliesst indessen zollrechtliche Massnahmen bezüglich der erfassten Produkte aus. Das Bundesgesetz über die Beseitigung technischer Handelshemmnisse verlangt die Anpassung an EU-rechtliche PPM Standards, soweit diese bestehen. Damit werden auch Spannungen im Rahmen des Freihandelsabkommens vermieden. Das THG erlaubt aber auch die ein- seitige Entwicklung von Best Practices und damit die Schaffung von Anreizen für die Ent- wicklung internationaler Standards. Das Cassis-de-Dijon Prinzip findet vorliegend keine unmittelbare Anwendung. Die hier behandelten Importregelungen beschränken sich auf die Rohstoffe und die unmittelbar daraus gewonnenen Basisprodukte. Sie lassen sich nicht auf verarbeitete Produkte übertragen. Diese können nur im Rahmen einer internationalen Harmonisierung miteinbezogen werden, welche alle Stufen der Verarbeitungsskette zu erfassen vermögen. Dies kann im Alleingang nicht erreicht werden.