The use of fibre optic sensing technology with intraluminal impedance catheter for functional gastrointestinal motility disorders

Author accepted manuscript made available with permission from Engineers Australia.We present a composite impedance fibre optic manometry catheter for monitoring functional gastrointestinal disorders (FGID). The catheter uses a dual lumen silicone extrusion to separate each technology and has been validated in ex-vivo animal models

Ascending excitatory neural pathways modulate slow phasic myogenic contractions in the isolated human colon

This is the accepted version of the following article: [Carbone, S. E., Dinning, P. G., Costa, M., Spencer, N. J., Brookes, S. J. H. and Wattchow, D. A. (2013), Ascending excitatory neural pathways modulate slow phasic myogenic contractions in the isolated human colon. Neurogastroenterology & Motility, 25: 670–e510.], which has been published in final form at [http://dx.doi.org/10.1111/nmo.12129]. In addition, authors may also transmit, print and share copies with colleagues, provided that there is no systematic distribution of the submitted version, e.g. posting on a listserve, network or automated delivery.Background In animal models, enteric reflex pathways have potent effects on motor activity; their roles have been much less extensively studied in human gut. The aim of this study was to determine if ascending excitatory interneuronal pathways can modulate spontaneous phasic contractions in isolated preparations of human colonic circular muscle. Methods Human colonic preparations were cut into T shapes, with vertical bar of the ‘T’ pharmacologically isolated. Electrical stimulation and the nicotinic agonist, 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), were applied to the isolated region and circular muscle contractile activity was measured from the cross-bar of the T, more than 10 mm orally from the region of stimulation. Key Results The predominant form of spontaneous muscle activity consisted of tetrodotoxin-resistant, large amplitude, slow phasic contractions (SPCs), occurring at average intervals of 124 ± 68 s. Addition of a high concentration of hexamethonium (1 mmol L-1) to the superfusing solution significantly increased the interval between SPCs to 278.1 ± 138.3 s (P < 0.005). Focal electrical stimulation more than 10 mm aboral to the muscle recording site advanced the onset of the next SPC, and this effect persisted in hexamethonium. However, the effect of electrical stimulation was blocked by tetrodotoxin (TTX, 1 µmol L-1). Application of the nicotinic agonist DMPP (1 mmol L-1) to the aboral chamber often stimulated a premature SPC (n = 4). Conclusions & Inferences The major form of spontaneous contractility in preparations of human colonic circular muscle is SPCs, which are myogenic in origin. Activation of ascending excitatory neural pathways, which involve nicotinic receptors, can modulate the timing of SPCs and thus influence human colonic motility.Australian National Health & Medical Research Counci

Prominent Role Of Platelets In The Formation Of Circulating Neutrophil-red Cell Heterocellular Aggregates In Sickle Cell Anemia.

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Activation of intestinal spinal afferent endings by changes in intra‐mesenteric arterial pressure

Author manuscript made available following 12 month embargo from date of publication (25 June 2015) in accordance with publisher copyright policy.KEY POINTS: A major class of mechano-nociceptors to the intestine have mechanotransduction sites on extramural and intramural arteries and arterioles ('vascular afferents'). These sensory neurons can be activated by compression or axial stretch of vessels. Using isolated preparations we showed that increasing intra-arterial pressure, within the physiological range, activated mechano-nociceptors on vessels in intact mesenteric arcades, but not in isolated arteries. This suggests that distortion of the branching vascular tree is the mechanical adequate stimulus for these sensory neurons, rather than simple distension. The same rises in pressure also activated intestinal peristalsis in a partially capsaicin-sensitive manner indicating that pressure-sensitive vascular afferents influence enteric circuits. The results identify the mechanical adequate stimulus for a major class of mechano-nociceptors with endings on blood vessels supplying the gut wall; these afferents have similar endings to ones supplying other viscera, striated muscle and dural vessels. ABSTRACT: Spinal sensory neurons innervate many large blood vessels throughout the body. Their activation causes the hallmarks of neurogenic inflammation: vasodilatation through the release of the neuropeptide calcitonin gene-related peptide and plasma extravasation via tachykinins. The same vasodilator afferent neurons show mechanical sensitivity, responding to crushing, compression or axial stretch of blood vessels - responses which activate pain pathways and which can be modified by cell damage and inflammation. In the present study, we tested whether spinal afferent axons ending on branching mesenteric arteries ('vascular afferents') are sensitive to increased intravascular pressure. From a holding pressure of 5 mmHg, distension to 20, 40, 60 or 80 mmHg caused graded, slowly adapting increases in firing of vascular afferents. Many of the same afferent units showed responses to axial stretch, which summed with responses evoked by raised pressure. Many vascular afferents were also sensitive to raised temperature, capsaicin and/or local compression with von Frey hairs. However, responses to raised pressure in single, isolated vessels were negligible, suggesting that the adequate stimulus is distortion of the arterial arcade rather than distension per se. Increasing arterial pressure often triggered peristaltic contractions in the neighbouring segment of intestine, an effect that was mimicked by acute exposure to capsaicin (1 μm) and which was reduced after desensitisation to capsaicin. These results indicate that sensory fibres with perivascular endings are sensitive to pressure-induced distortion of branched arteries, in addition to compression and axial stretch, and that they contribute functional inputs to enteric motor circuits

Characterization of Esophageal Physiology Using Mechanical State Analysis

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution and reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.The esophagus functions to transport swallowed fluids and food from the pharynx to the stomach. The esophageal muscles governing bolus transport comprise circular striated muscle of the proximal esophagus and circular smooth muscle of the distal esophagus. Longitudinal smooth muscle contraction provides a mechanical advantage to bolus transit during circular smooth muscle contraction. Esophageal striated muscle is directly controlled by neural circuits originating in the central nervous system, resulting in coordinated contractions. In contrast, the esophageal smooth muscle is controlled by enteric circuits modulated by extrinsic central neural connections resulting in neural relaxation and contraction. The esophageal muscles are modulated by sensory information arising from within the lumen. Contraction or relaxation, which changes the diameter of the lumen, alters the intraluminal pressure and ultimately inhibits or promotes flow of content. This relationship that exists between the changes in diameter and concurrent changes in intraluminal pressure has been used previously to identify the "mechanical states" of the circular muscle; that is when the muscles are passively or actively, relaxing or contracting. Detecting these changes in the mechanical state of the muscle has been difficult and as the current interpretation of esophageal motility is based largely upon pressure measurement (manometry), subtle changes in the muscle function during peristalsis can be missed. We hypothesized that quantification of mechanical states of the esophageal circular muscles and the pressure-diameter properties that define them, would allow objective characterization of the mechanisms that govern esophageal peristalsis. To achieve this we analyzed barium swallows captured by simultaneous videofluoroscopy and pressure with impedance recording. From these data we demonstrated that intraluminal impedance measurements could be used to determine changes in the internal diameter of the lumen comparable with measurements from videofluoroscopy. Our data indicated that identification of mechanical state of esophageal muscle was simple to apply and revealed patterns consistent with the known neural inputs activating the different muscles during swallowing

Fatores motivacionais para a prática do futebol de campo em jovens atletas

Objetivo: a analisar os fatores motivacionais para adesão e prática do futebol de campo em jovens atletas de um município do interior do Rio Grande do Sul. Método: fizeram parte da amostra todos os jovens participantes de uma escolinha de futebol amador, partindo das categorias Sub-10 até a Sub-17 que aceitaram participar do estudo voluntariamente. Como instrumento de coleta de dados utilizou um questionário sobre caracterização sociodemográfico, Inventário de Motivação para a Prática Desportiva e um questionário sobre os principais motivos da adesão ao futebol. Para analisar os dados utilizou-se a estatística descritiva. Resultados: os resultados demonstraram que a distribuição econômica das famílias dos atletas estavam distribuídas nos extratos B2, C1, C2 e D-E, tinham como principal influência para a adesão ao futebol os amigos e o desejo de ser um jogador profissional. As motivações para a prática de futebol de campo estavam relacionadas principalmente às dimensões Rendimento Esportivo e Saúde. Considerações finais: evidenciou-se que os jovens atletas têm maior envolvimento no futebol por fatores intrínsecos, como, a vontade de vencer e de conseguir ter uma melhora a cada dia, devido a competitividade que esse esporte gera em cada etapa da vida

Measurement of Muscular Activity Associated With Peristalsis in the Human Gut Using Fiber Bragg Grating Arrays

Author version made available under Publisher copyright policy.Diagnostic catheters based on fibre Bragg gratings (FBG’s) are proving to be highly effective for measurement of the muscular activity associated with peristalsis in the human gut. The primary muscular contractions that generate peristalsis are circumferential in nature; however, it has long been known that there is also a component of longitudinal contractility present, acting in harmony with the circumferential component to improve the overall efficiency of material movement. We report on the development of, and latest results from, catheter based sensors capable of detecting both forms of muscular activity. While detection of the circumferential contractions has been possible using solid state, hydraulic, and pneumatic sensor arrays in the oesophagus and anorectum, FBG based devices allow access into the complex and convoluted regions of the gut below the stomach. We report early results from FBG catheters used during trials of novel therapies in patients with both slow transit constipation and faecal incontinence. In addition, there have been relatively few reports on the measurement or inference of longitudinal contractions in humans. This is due to the lack of a viable recording technique suitable for real-time in-vivo measurement of this type of activity over extended lengths of the gut. We report preliminary data on the detection of longitudinal motion in lengths of excised mammalian colon using an FBG technique that should be viable for similar detection in humans. The longitudinal sensors have been combined with pressure sensing elements to form a composite catheter that allows the relative phase between the two components to be detected. The output of both types of catheter has been validated using digital video mapping in an ex-vivo animal preparation using lengths of rabbit ileum

Accurate Atmospheric Parameters at Moderate Resolution Using Spectral Indices: Preliminary Application to the MARVELS Survey

Studies of Galactic chemical and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (Teff, [Fe/H] and log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in observing large samples, which makes the stellar characterization difficult due to the high degree of blending of spectral features. While most surveys use spectral synthesis, in this work we employ an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving power (R~12,000). We have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices and, through the comparison of those with values calculated with pre-determined calibrations, derive the atmospheric parameters of the stars. The calibrations were built using a sample of 309 stars with precise stellar parameters obtained from the analysis of high-resolution FEROS spectra. A validation test of the method was conducted with a sample of 30 MARVELS targets that also have reliable atmospheric parameters from high-resolution spectroscopic analysis. Our approach was able to recover the parameters within 80 K for Teff, 0.05 dex for [Fe/H] and 0.15 dex for log g, values that are lower or equal to the typical external uncertainties found between different high-resolution analyzes. An additional test was performed with a subsample of 138 stars from the ELODIE stellar library and the literature atmospheric parameters were recovered within 125 K for Teff, 0.10 dex for [Fe/H] and 0.29 dex for log g. These results show that the spectral indices are a competitive tool to characterize stars with the intermediate resolution spectra.Comment: Accepted for publication in AJ. Abstract edited to comply with arXiv standards regarding the number of character

Integrating Fronthaul and Backhaul Networks: Transport Challenges and Feasibility Results

In Press / En PrensaIn addition to CPRI, new functional splits have been defined in 5G creating diverse fronthaul transport bandwidth and latency requirements. These fronthaul requirements shall be fulfilled simultaneously together with the backhaul requirements by an integrated fronthaul and backhaul transport solution. In this paper, we analyze the technical challenges to achieve an integrated transport solution in 5G and propose specific solutions to address these challenges. These solutions have been implemented and verified with commercially available equipment. Our results confirm that an integrated fronthaul and backhaul transport dubbed Crosshaul can meet all the requirements of 5G fronthaul and backhaul in a cost-efficient manner.Special thanks to the 5G-Crosshaul and 5G-TRANSFORMER team, in particular to Jaime Jose Garcia Reinoso, Chenguang Lu, Daniel Cederholm and Jakub Kocur who helped during the experimentation. This work has been partially funded by the EU H2020 project "5G-TRANSFORMER: 5G Mobile Transport Platform for Verticals" (grant no. 761536)