Mechanisms of vasomotor sympathetic activity generation in the renovascular hypertension in Wistar rats

The renovascular arterial hypertension (AH) is associated with sympathetic hyperactivity and impaired baroreflex sensitivity determined by increase in circulating angiotensin II (Ang II). The aim of this thesis was to evaluate the role of oxidative stress in the generation and maintenance of the AH (2 Kidney – 1 Clip). Five series of experiments were performed in male Wistar. The results showed autonomic cardiovascular control changes characterized by increased sympathetic modulation in blood vessels, impaired baroreflex sensitivity and tachycardia from the fourth week. Furthermore, we observed that Ang II (via AT-1 receptor) and NO (produced by iNOS) in the rostral ventrolateral medulla (RVLM) are involved in the maintenance of AH and renal sympathetic nerve activity in the 2K-1C. Indeed, there is an imbalance between pro-oxidants and antioxidants in the RVL and hypothalamic paraventricular nucleus (PVN) of animals 2K-1C, because the increase in blood pressure (BP) and sympathetic hyperactivity was reversed in response to administration of the antioxidant (Tempol) into the RVLM and PVN. The over expression of CuZnSOD in the RVLM prevented the AH and reduced the production of superoxide in this region in 2K-1C. Furthermore, improved the impaired baroreflex sensitivity and inhibited the tachycardia observed from the fourth week of AH. Chronic Vitamin C treatment decreased BP and sympathetictactivation in hypertensive animals. In addition, reduced gene expression of subunits of NAD (P) H oxidase in the PVN and RVLM, but unchanged the expression of CuZnSOD. Oxidative stress also seems to influence the gene expression of AT-1 receptor, iNOS, nNOS, IL-1 â and Glut-1 in the PVN and RVL regions, because the treatment reduced the expression of these components. Based on our results, we suggest that the angiotensin system, NO and oxidative stress in the PVN and RVLM are involved in the maintenance of sympathetic tone and the AH 2K-1C. Oxidative stress in sympathetic premotor neurons is a major mechanism for the establishment and maintenance of Ang II – dependent hypertension.A Hipertensão arterial (HA) renovascular está associada com uma hiperatividade simpática e prejuízo na sensibilidade reflexa do barorreceptor determinadas por aumento na Angiotensina II (Ang II) circulante. O objetivo da presente Tese foi avaliar o papel do estresse oxidativo na geração e manutenção da HA 2 Rins-1Clipe. Ratos Machos Wistar foram utilizados em cinco séries de experimentos. Os resultados demonstraram uma alteração no controle autonômico cardíaco caracterizado por maior modulação simpática nos vasos, um prejuízo da sensibilidade reflexa do barorreceptor e taquicardia a partir da quarta semana. Além disso, observou-se que Ang II (via receptor AT-1) e o NO (produzido pela iNOS) na região rostro ventrolateral do bulbo (RVL), participam mantendo a HA e a atividade nervosa simpática renal em ratos 2R-1C. Evidenciou-se um desequilíbrio entre próoxidantes e antioxidantes, caracterizando um estado de estresse oxidativo nas regiões RVL e no núcleo paraventricular (PVN) dos animais 2R-1C, visto que o aumento de pressão arterial (PA) e a hiperatividade simpática são revertidos com a administração do antioxidante (Tempol) nessas regiões. A super expressão crônica de CuZnSOD na região RVL preveniu a HA e reduziu a produção de superóxidos nessa região em ratos 2R-1C. Além disso, melhorou a sensibilidade reflexa do barorreceptor e inibiu a taquicardia observada a partir da quarta semana de HA. O tratamento crônico com Vitamina C promoveu queda da PA e simpato-inibição nos animais hipertensos. Além disso, reduziu a expressão gênica das subunidades de NAD(P)H oxidase nas regiões RVL e PVN, mas não interferiu na expressão de CuZnSOD. O estresse oxidativo também parece influenciar na expressão gênica do receptor AT-1, iNOS, nNOS, IL-1 ƒÀ e Glut-1 nas regioes RVL e PVN, visto que o tratamento reduziu a expressao desses componentes. Baseado em nossos resultados, podemos sugerir que o sistema angiotensinergico, nitrergico e o estresse oxidativo nas regioes RVL e PVN estao envolvidos na manutencao do tonus simpatico e da HA 2R-1C. O estresse oxidativo em neuronios pre-motores do simpatico e um mecanismo essencial para o estabelecimento e manutencao da HA Ang II - dependente.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPESP: 05/60151-6CAPES/BEX: 3496/07-4TEDEBV UNIFESP: Teses e dissertaçõe

Revealing the role of the autonomic nervous system in the development and maintenance of Goldblatt hypertension in rats

Despite extensive use of the renovascular/Goldblatt model of hypertension-2K-1C, and the use of renal denervation to treat drug resistant hypertensive patients, autonomic mechanisms that underpin the maintenance of this hypertension are important yet remain unclear. Our aim was to analyse cardiovascular autonomic function by power spectral density analysis of both arterial pressure and pulse interval measured continuously by radio telemetry for 6 weeks after renal artery clipping. Mean arterial pressure increased from 106 +/- 5 to 185 +/- 2 mm Hg during 5 weeks post clipping when it stabilized. A tachycardia developed during the 4th week, which plateaued between weeks 5 and 6. the gain of the cardiac vagal baroreflex decreased immediately after clipping and continued to do so until the 5th week when it plateaued (from -2.4 +/- 0.09 to -0.8 +/- 0.04 bpm/mm Hg; P < 0.05). A similar time course of changes in the high frequency power spectral density of the pulse interval was observed (decrease from 13.4 +/- 0.6 to 8.3 +/- 0.01 ms(2); P < 0.05). There was an increase in both the very low frequency and low frequency components of systolic blood pressure that occurred 3 and 4 weeks after clipping, respectively. Thus, we show for the first time the temporal profile of autonomic mechanisms underpinning the initiation, development and maintenance of renovascular hypertension including: an immediate depression of cardiac baroreflex gain followed by a delayed cardiac sympathetic predominance; elevated sympathetic vasomotor drive occurring after the initiation of the hypertension but coinciding during its mid-development and maintenance. (C) 2014 the Authors. Published by Elsevier B.V.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)British Heart FoundationNIHUniv Bristol, Sch Physiol & Pharmacol, Bristol BS8 1TD, Avon, EnglandUniversidade Federal de São Paulo, UNIFESP, Dept Physiol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Physiol, BR-04023062 São Paulo, BrazilWeb of Scienc

Simulation–Optimization Modeling: A Survey and Potential Application in Reservoir Systems Operation

This paper presents a survey of simulation and optimization modeling approaches used in reservoir systems operation problems. Optimization methods have been proved of much importance when used with simulation modeling and the two approaches when combined give the best results. The main objective of this review article is to discuss simulation, optimization and combined simulation– optimization modeling approach and to provide an overview of their applications reported in literature. In addition to classical optimization techniques, application and scope of computational intelligence techniques, such as, evolutionary computa- tions, fuzzy set theory and artificial neural networks, in reservoir system operation studies are reviewed. Conclusions and suggestive remarks based on this survey are outlined, which could be helpful for future research and for system managers to decide appropriate methodology for application to their systems

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

The Amazon Tall Tower Observatory (ATTO): Overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It has already been changed significantly by human activities, and more pervasive change is expected to occur in the coming decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region, as human perturbations increase in the future. The Amazon Tall Tower Observatory (ATTO) has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at five to eight different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity). Aerosol optical, microphysical, and chemical measurements are being made above the canopy as well as in the canopy space. They include aerosol light scattering and absorption, fluorescence, number and volume size distributions, chemical composition, cloud condensation nuclei (CCN) concentrations, and hygroscopicity. In this paper, we discuss the scientific context of the ATTO observatory and present an overview of results from ecological, meteorological, and chemical pilot studies at the ATTO site. © Author(s) 2015

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

The leading conduct in renovascular hypertension

Introduction: The Renovascular hypertension (RH) is the leading cause of secondary hypertension. The main cause for RH is renal arterial stenosis and with early treatment is possible to reverse the clinical state. Therefore, the diagnosis and choice of a proper treatment are extremely important, especially in this pathology.Methodology: Thus, this paper aimed to conduct a narrative review, using articles from indexed journals and narrative and systematic reviews of Medline, SciELO and Cochrane CENTRAL databases, comparing comparing the use of stent in cirurgical intervention versus the use of medical drugs in the treatment of RH. Results: In none of the studies (RADAR, RAOOD) or systemic reviews or metaanalysee was observed the restoration of renal function. Discussion: The diseases occur due to decreased blood flow of the renal artery, usually by an atheroma plaque. The physiopathology of RH disease consists in the interaction between the renin-angiotensin-aldosterone system (RAAS), that when activated is responsible for sodium and volume retention, combined with other pressure systems such as Sympathetic Nervous System. RH treatment can be performed through drug therapy, mainly ACE inhibitors or through surgical intervention with stent placement. Conclusion: The conclusion observed was that the efficiency of the stent when combined with the use of pharmacos, obtaining an improvement in the clinical picture