Impaired flow-induced arterial remodeling in DOCA-salt hypertensive rats

Arteries from young healthy animals respond to chronic changes in blood flow and blood pressure by structural remodeling. We tested whether the ability to respond to decreased (-90%) or increased (+100%) blood flow is impaired during the development of deoxycorticosterone acetate (DOCA)-salt hypertension in rats, a model for an upregulated endothelin-1 system. Mesenteric small arteries (MrA) were exposed to low blood flow (LF) or high blood flow (HF) for 4 or 7 weeks. The bioavailability of vasoactive peptides was modified by chronic treatment of the rats with the dual neutral endopeptidase (NEP)/endothelin-converting enzyme (ECE) inhibitor SOL1. After 3 or 6 weeks of hypertension, the MrA showed hypertrophic arterial remodeling (3 weeks: media cross-sectional area (mCSA): 10 +/- 1 x 10(3) to 17 +/- 2 x 10(3) mu m(2); 6 weeks: 13 +/- 2 x 10(3) to 24 +/- 3 x 10(3) mu m(2)). After 3, but not 6, weeks of hypertension, the arterial diameter was increased (empty set: 385 +/- 13 to 463 +/- 14 mu m). SOL1 reduced hypertrophy after 3 weeks of hypertension (mCSA: 6 x 10(3) +/- 1 x 10(3) mu m(2)). The diameter of the HF arteries of normotensive rats increased (empty set: 463 +/- 22 mu m) but no expansion occurred in the HF arteries of hypertensive rats (empty set: 471 +/- 16 mu m). MrA from SOL1-treated hypertensive rats did show a significant diameter increase (empty set: 419 +/- 13 to 475 +/- 16 mu m). Arteries exposed to LF showed inward remodeling in normotensive and hypertensive rats (mean empty set between 235 and 290 mu m), and infiltration of monocyte/ macrophages. SOL1 treatment did not affect the arterial diameter of LF arteries but reduced the infiltration of monocyte/ macrophages. We show for the first time that flow-induced remodeling is impaired during the development of DOCA-salt hypertension and that this can be prevented by chronic NEP/ECE inhibition. Hypertension Research (2012) 35, 1093-1101; doi:10.1038/hr.2012.94; published online 12 July 201

Reducing Overvoltage Problems with Active Power Curtailment - Simulation Results

High penetration levels of photovoltaic systems on low voltage electricity nets tend to lead to overvoltage problems. Currently, in the residential sector of the Belgian Flanders region, the only way to reduce those problems is by means of completely halting the inverter. This paper investigates the power quality improvements of a fixed method of gradual active power curtailment in order to minimize overvoltage problems, as well as a basic economic impact on the end user. The method is simulated on 3 models of existing low voltage feeders located in the northern region of Belgium. Results show that overvoltage problems are nullified and unbalance is improved. © 2013 IEEE.status: publishe

Standalone LV Distribution Network Voltage Control Mechanism

This paper describes a voltage stabilizing control mechanism using the available flexibility of smart devices within one household. The flexibility of all types of smart appliances is used, especially smart on/off devices. The main advantage of the developed control system is that it does not require a communication network between the different households, only locally available measurements, such as the household supply voltage, are taken into account. The control system will be rolled out in a real life pilot test. Simulation results point out that the amount of over and under voltage occurrences on average are lowered with 35%. © 2013 IEEE.status: publishe

Distributed Voltage Control Mechanism in Low-Voltage Distribution Grid Field Test

In this paper, we present a distributed voltage control mechanism that is being used in the large-scale field-test of the Linear project. The control system developed does not require a communication network between the different households. Only the locally measured household supply voltage is taken into account. The proposed control system is compatible with DSM infrastructure currently being developed, such as home gateways and smart meters. Moreover, the proposed control system can also be used as a fallback mechanism for other communication-based DSM control systems when communication fails or when the system has been compromised due to cyber security issues. Using Monte Carlo simulations on two accurately modeled field test grids and device models, the proposed approach and its various parameter set points are benchmarked against the optimal Dynamic Programming solution. Simulation results point out that on average the amount of over and under voltage occurrences can be lowered by more than 30 %e-onlystatus: publishe

Clinical aspects of chronic ENT inflammation in children.

In children, all ENT cavities are particularly prone to the development of chronic inflammation. This is due to many predisposing factors, of which the most common are unfavourable anatomy, absence of nasal blowing, day care attendance, allergy, immature immunity, gastro-oesophageal reflux and tobacco smoke exposure. The aim of this paper is to outline the most specific paediatric clinical aspects of chronic pharyngo-tonsillitis, rhinosinusitis, otitis media, adenoiditis and laryngotracheitis and the important influence that some of these pathologies exert on the others.Journal ArticleReviewSCOPUS: re.jinfo:eu-repo/semantics/publishe

Gait and Falls in Benign Paroxysmal Positional Vertigo:A Systematic Review and Meta-analysis

Background and Purpose: Benign paroxysmal positional vertigo (BPPV) is one of the most common vestibular disorders, and is treated effectively with particle repositioning maneuvers (PRM). The aim of this study was to assess the influence of BPPV and treatment effects of PRM on gait, falls, and fear of falling. Methods: Three databases and the reference lists of included articles were systematically searched for studies comparing gait and/or falls between (1) people with BPPV (pwBPPV) and controls and (2) pre- and posttreatment with PRM. The Joanna Briggs Institute critical appraisal tools were used to assess risk of bias. Results: Twenty of the 25 included studies were suitable for meta-analysis. Quality assessment resulted in 2 studies with high risk of bias, 13 with moderate risk, and 10 with low risk. PwBPPV walked slower and demonstrated more sway during tandem walking compared with controls. PwBPPV also walked slower during head rotations. After PRM, gait velocity during level walking increased significantly, and gait became safer according to gait assessment scales. Impairments during tandem walking and walking with head rotations did not improve. The number of fallers was significantly higher for pwBPPV than for controls. After treatment, the number of falls, number of pwBPPV who fell, and fear of falling decreased. Discussion and Conclusions: BPPV increases the odds of falls and negatively impacts spatiotemporal parameters of gait. PRM improves falls, fear of falling, and gait during level walking. Additional rehabilitation might be necessary to improve gait while walking with head movements or tandem walking

Dual neural endopeptidase/endothelin-converting [corrected] enzyme inhibition improves endothelial function in mesenteric resistance arteries of young spontaneously hypertensive rats

Background: Endothelin-1 (ET1) is a potent vasoconstrictor peptide with pro-mitogenic and pro-inflammatory properties and is therefore of interest in the development of endothelial dysfunction, endothelium-dependent flow-related remodeling, and hypertension-related remodeling. ET1 can be formed through cleavage of big ET1 by endothelin-converting enzyme (ECE) and neutral endopeptidase (NEP). Method: We investigated whether the dual NEP/ECE inhibitor SOL1 improves resistance artery function and structure in 12 weeks old spontaneously hypertensive rats (SHRs) and whether arterial structural responses to decreased (-90%) or increased (+100%) blood flow are impaired in young SHRs. To this end two groups of SHRs received chronic 4-week treatment at two different time points (4-8 and 8-12 weeks) prior to the experiment. We compared in-vitro effects of cyclo-oxygenase inhibition (1 mu mol/l indomethacine), nitric oxide synthase inhibition (100 mu mol/l N-omega-L-nitro arginine methyl ester), and stimulation of the endothelium by 0.001-10 mu mol/l acetylcholine (ACh) in isolated third-order mesenteric arteries of SHRs and aged-matched Wistar-Kyoto (WKY) rats. Results: SOL1 had no effect on blood pressure in SHRs or WKY rats. ACh caused biphasic effects in mesenteric arteries of SHRs. The contractile component (endothelium-derived contractile factor) was absent in WKY and abolished by acute indomethacin administration or chronic SOL1 treatment. Endothelium-derived nitric oxide-type responses did not differ in both strains and were not influenced by SOL1 treatment. Endothelium-derived hyperpolarizing factor-type responses were severely impaired in SHRs as compared to WKY rats and were normalized by chronic SOL1 treatment. In first-order mesenteric arteries, outward flow-induced remodeling was impaired in SHRs. Chronic SOL1 treatment did not restore this response. Conclusion: Thus chronic SOL1 treatment during the development of hypertension in SHRs has no effect on blood pressure but improves several aspects of endothelium-dependent vasomotor responses but not arterial remodeling