Adaptations to iron deficiency: cardiac functional responsiveness to norepinephrine, arterial remodeling, and the effect of beta-blockade on cardiac hypertrophy.

BackgroundIron deficiency (ID) results in ventricular hypertrophy, believed to involve sympathetic stimulation. We hypothesized that with ID 1) intravenous norepinephrine would alter heart rate (HR) and contractility, 2) abdominal aorta would be larger and more distensible, and 3) the beta-blocker propanolol would reduce hypertrophy.Methods1) 30 CD rats were fed an ID or replete diet for 1 week or 1 month. Norepinephrine was infused via jugular vein; pressure was monitored at carotid artery. Saline infusions were used as a control. The pressure trace was analyzed for HR, contractility, systolic and diastolic pressures. 2) Abdominal aorta catheters inflated the aorta, while digital microscopic images were recorded at stepwise pressures to measure arterial diameter and distensibility. 3) An additional 10 rats (5 ID, 5 control) were given a daily injection of propanolol or saline. After 1 month, the hearts were excised and weighed.ResultsEnhanced contractility, but not HR, was associated with ID hypertrophic hearts. Systolic and diastolic blood pressures were consistent with an increase in arterial diameter associated with ID. Aortic diameter at 100 mmHg and distensibility were increased with ID. Propanolol was associated with an increase in heart to body mass ratio.ConclusionsID cardiac hypertrophy results in an increased inotropic, but not chronotropic response to the sympathetic neurotransmitter, norepinephrine. Increased aortic diameter is consistent with a flow-dependent vascular remodeling; increased distensibility may reflect decreased vascular collagen content. The failure of propanolol to prevent hypertrophy suggests that ID hypertrophy is not mediated via beta-adrenergic neurotransmission

Anaesthetic management of a patent ductus arteriosus (PDA) occlusion using an Amplatz canine duct occluder (ACDO) in a dog

Patent ductus arteriosus (PDA) is one of the most common diagnosed congenital disease in dogs that usually causes heart failure and death unless corrected at a young age. A 2.5-year-old female intact Coton de Tuléar was referred and diagnosed with a left to right shunt PDA. Closure of the PDA was performed via a minimally invasive approach by means of an Amplatz canine duct occluder device. In this case report, we describe a successful anaesthetic protocol that included premedication using a combination of acepromazine and methadone, induction with propofol and midazolam and maintenance with isoflurane in oxygen, as well as a lidocaine constant rate constant rate infusion for intraoperative analgesic and cardiovascular support. This protocol provided excellent intraoperative cardiopulmonary stability and a smooth and rapid recovery

Ylikuorman hallinta Diameter-protokollassa liikkuvuuden hallintaa varten

The purpose of this thesis is to develop an overload control solution for Diameter protocol traffic between the MME and HSS in the EPC. The solution is based on using overload information from HSSs and throttling the traffic as needed based on the information. Diameter message prioritization is used to enable ongoing trans- actions to succeed and thus reduce the overload. The performance of the solution is measured with four indicators measuring various aspects of the system's performance. Performance measurements are done via simulations and their results show a clear improvement in system performance when the solution is enabled.Työn tarkoituksena on kehittää ylikuormanhallintaratkaisu neljännen sukupolven matkapuhelinverkkojen ytimen EPC:n MME- ja HSS-verkkoelementtien väliselle Diameter-protokollan yli tapahtuvalle liikenteelle. Hallintaratkaisu perustuu HSS- elementin MME-elementille välittämään tietoon ylikuormasta ja siihen perustuvaan MME-elementin tarpeen vaatiessa tekemään liikenteen rajoittamiseen. Käynnissä olevien transaktioiden lähettämisen onnistuminen varmistetaan käyttämällä Diameter-sanomien priorisointia, mikä vähentää ylikuormaa, kun niitä ei tarvitse lähettää uudestaan. Ratkaisun suorituskykyä mittaamaan on kehitetty neljä eri osa-alueiden suorituskykyä kuvaavaa mittaria. Varsinainen suorituskyvyn mittaus on tehty toteuttamalla ratkaisua simuloiva sovellus ja simulaatioiden tulokset osoittavat järjestelmän suorituskyvyn selkeästi parantuneen ratkaisun ollessa käytössä

Self-Configuration and Self-Optimization Process in Heterogeneous Wireless Networks

Self-organization in Wireless Mesh Networks (WMN) is an emergent research area, which is becoming important due to the increasing number of nodes in a network. Consequently, the manual configuration of nodes is either impossible or highly costly. So it is desirable for the nodes to be able to configure themselves. In this paper, we propose an alternative architecture for self-organization of WMN based on Optimized Link State Routing Protocol (OLSR) and the ad hoc on demand distance vector (AODV) routing protocols as well as using the technology of software agents. We argue that the proposed self-optimization and self-configuration modules increase the throughput of network, reduces delay transmission and network load, decreases the traffic of HELLO messages according to network’s scalability. By simulation analysis, we conclude that the self-optimization and self-configuration mechanisms can significantly improve the performance of OLSR and AODV protocols in comparison to the baseline protocols analyzed

Combining social network analysis and the NATO Approach Space to define agility. Topic 2: networks and networking

This paper takes the NATO SAS-050 Approach Space, a widely accepted model of command and control, and gives each of its primary axes a quantitative measure using social network analysis. This means that the actual point in the approach space adopted by real-life command and control organizations can be plotted along with the way in which that point varies over time and function. Part 1 of the paper presents the rationale behind this innovation and how it was subject to verification using theoretical data. Part 2 shows how the enhanced approach space was put to use in the context of a large scale military command post exercise. Agility is represented by the number of distinct areas in the approach space that the organization was able to occupy and there was a marked disparity between where the organization thought it should be and where it actually was, furthermore, agility varied across function. The humans in this particular scenario bestowed upon the organization the levels of agility that were observed, thus the findings are properly considered from a socio-technical perspective

Failure phenomena in two-dimensional multi-fibre microcomposites, Part 2: A Raman spectroscopic study into the influence of inter-fibre spacing on stress concentrations

Raman spectroscopy is used to determine the influence of inter-fibre spacing on the stress concentration factor (SCF) resulting from a fibre break in a two-dimensional (2-D) carbon/epoxy microcomposite. Microcomposites with an inter-fibre spacing varying from 0.8–19.0 fibre diameters (f) have been investigated. The SCF was found to decrease from a value of 1.26 at an inter-fibre spacing of 0.8f to a value of 1.06 at an inter-fibre spacing of 10.4f. The experimentally found variation of SCF with inter-fibre spacing was compared to some analytical models available in the literature. It was found that none of the models is able to describe the experimental data adequately. The effect of the SCF on the failure process is also discussed. At relatively small inter-fibre spacings the SCF is sufficiently high to cause further fibre failure in neighbouring fibres resulting in alignment of fibre breaks. At increasing inter-fibre spacing the decrease in SCF results in a decreasing influence of the initial fibre break on the progressive fibre failure process and the failure process becomes more random

Oligodendrocytes, BK channels and the preservation of myelin

Oligodendrocytes wrap multiple lamellae of their membrane, myelin, around axons of the central nervous system (CNS), to improve impulse conduction. Myelin synthesis is specialised and dynamic, responsive to local neuronal excitation. Subtle pathological insults are sufficient to cause significant neuronal metabolic impairment, so myelin preservation is necessary to safeguard neural networks. Multiple sclerosis (MS) is the most prevalent demyelinating disease of the CNS. In MS, inflammatory attacks against myelin, proposed to be autoimmune, cause myelin decay and oligodendrocyte loss, leaving neurons vulnerable. Current therapies target the prominent neuroinflammation but are mostly ineffective in protecting from neurodegeneration and the progressive neurological disability. People with MS have substantially higher levels of extracellular glutamate, the main excitatory neurotransmitter. This impairs cellular homeostasis to cause excitotoxic stress. Large conductance Ca2+-activated K+ channels (BK channels) could preserve myelin or allow its recovery by protecting cells from the resulting excessive excitability. This review evaluates the role of excitotoxic stress, myelination and BK channels in MS pathology, and explores the hypothesis that BK channel activation could be a therapeutic strategy to protect oligodendrocytes from excitotoxic stress in MS. This could reduce progression of neurological disability if used in parallel to immunomodulatory therapies

Oligodendrocytes, BK channels and the preservation of myelin.

Oligodendrocytes wrap multiple lamellae of their membrane, myelin, around axons of the central nervous system (CNS), to improve impulse conduction. Myelin synthesis is specialised and dynamic, responsive to local neuronal excitation. Subtle pathological insults are sufficient to cause significant neuronal metabolic impairment, so myelin preservation is necessary to safeguard neural networks. Multiple sclerosis (MS) is the most prevalent demyelinating disease of the CNS. In MS, inflammatory attacks against myelin, proposed to be autoimmune, cause myelin decay and oligodendrocyte loss, leaving neurons vulnerable. Current therapies target the prominent neuroinflammation but are mostly ineffective in protecting from neurodegeneration and the progressive neurological disability. People with MS have substantially higher levels of extracellular glutamate, the main excitatory neurotransmitter. This impairs cellular homeostasis to cause excitotoxic stress. Large conductance Ca2 +-activated K + channels (BK channels) could preserve myelin or allow its recovery by protecting cells from the resulting excessive excitability. This review evaluates the role of excitotoxic stress, myelination and BK channels in MS pathology, and explores the hypothesis that BK channel activation could be a therapeutic strategy to protect oligodendrocytes from excitotoxic stress in MS. This could reduce progression of neurological disability if used in parallel to immunomodulatory therapies