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Brain tissue oxygen

Ashraf Al Tayar, Amr Abouelela, Khaja Mohiuddeen
INTRODUCTION: Shock, defined as a state of tissue hypoperfusion and the tissues reperfusion, is the main goal of management of shock. Increase in central venous saturation (CvSo2) and decrease in blood lactate level are useful in assessment of adequacy of tissue perfusion. Near-infrared spectroscopy is a noninvasive way to observe real-time changes in regional cerebral saturation and has been used in patients with different brain diseases. There is a small body of literature suggesting that cerebral regional oxygen saturation (CrSo2) monitoring added a value in assessment and management of intensive care unit (ICU) patients...
November 10, 2016: Journal of Critical Care
Juan A Ardura, Verónica Alonso, Pedro Esbrit, Peter A Friedman
Reactive Oxygen Species (ROS) increase during aging, potentially affecting many tissues including brain, heart, and bone. ROS alter signaling pathways and constitute potential therapeutic targets to limit oxidative damaging effects in aging-associated diseases. Parathyroid hormone receptors (PTHR) are widely expressed and PTH is the only anabolic therapy for osteoporosis. The effects of oxidative stress on PTHR signaling and trafficking have not been elucidated. Here, we used Fluorescence Resonance Energy Transfer (FRET)-based cAMP, ERK, and calcium fluorescent biosensors to analyze the effects of ROS on PTHR signaling and trafficking by live-cell imaging...
November 28, 2016: Biochemical and Biophysical Research Communications
Laura Terraneo, Paola Bianciardi, Ashok Malavalli, Gnel Mkrtchyan, Stephanie N Spann, Jeff Lohman, Michele Samaja, Kim D Vandegriff
Haemoglobin (Hb)-based oxygen carriers are under consideration as oxygen therapeutics. Their effect on apoptosis is critical, because the onset of pro-apoptotic pathways may lead to tissue damage. MP4OX, a polyethylene glycol-conjugated human Hb preserves the baseline level of neuron apoptosis with respect to sham. Here we develop a method for measuring Hb extravasation in brain. We exchange transfused rats by haemorrhaging 50% of their blood with simultaneous, isovolemic replacement with Hextend (negative control), MP4OX, or αα-cross-linked Hb...
December 1, 2016: Artificial Cells, Nanomedicine, and Biotechnology
Menno R Germans, Hieronymus D Boogaarts, R Loch Macdonald
Ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, and traumatic brain injury-all have in common early brain injury due to brain tissue destruction, reduced cerebral blood flow and oxygen delivery, and overall substantial morbidity and mortality. The pathophysiology of brain tissue damage likely includes common cellular mechanisms. Neuroprotection has seldom, if ever, been shown to reduce early brain injury. Secondary brain injury develops after these conditions due to macroscopic events such as increased intracranial pressure and reduced cerebral blood flow, as well as cellular processes including vascular damage, inflammation, and apoptotic/necrotic cell death...
December 2016: Seminars in Neurology
Charles L Francoeur, Margaret Pain, Stephan A Mayer
The field of neurocritical care has evolved tremendously in recent years, a development explained vastly by the advent of neurophysiological monitoring. From basic intracranial pressure measurements to brain tissue oxygenation, microdialysis, cerebral blood flow (CBF), and surface and intracortical electroencephalography (EEG), our ability to detect and control physiologic endpoints of brain function in comatose patients has grown substantially. The integration of these data gave birth to the concept of multimodality monitoring (MMM)...
December 2016: Seminars in Neurology
Fernanda Moreira Lopes, Sergiane Souza Caldas, Ednei Gilberto Primel, Carlos Eduardo da Rosa
It has been demonstrated that glyphosate-based herbicides are toxic to animals. In the present study, reactive oxygen species (ROS) generation, antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO), as well as the activity and expression of the acetylcholinesterase (AChE) enzyme, were evaluated in Danio rerio males exposed to 5 or 10 mg/L of glyphosate for 24 and 96 h. An increase in ACAP in gills after 24 h was observed in the animals exposed to 5 mg/L of glyphosate. A decrease in LPO was observed in brain tissue of animals exposed to 10 mg/L after 24 h, while an increase was observed in muscle after 96 h...
December 1, 2016: Zebrafish
Geetika Garg, Sandeep Singh, Abhishek Kumar Singh, Syed Ibrahim Rizvi
Metformin, a biguanide, is a widely used anti-diabetic drug which inhibits gluconeogenesis and is used to treat hyperglycemia in type 2 diabetes. Through activation of AMPK pathway, metformin also mimics caloric restriction health benefits. Aging causes substantial molecular to morphological changes in brain, the brain cells being more susceptible towards oxidative stress mediated damages due to the presence of high lipid content and higher oxygen consumption. Wistar rats (naturally aged and D Galactose induced rat model) were supplemented with metformin (300 mg/kg b...
November 29, 2016: Rejuvenation Research
Linhui Yu, Ying Wu, Jeff F Dunn, Kartikeya Murari
We propose a single fiber optical system for monitoring tissue oxygen saturation (sO2) based on continuous-wave reflectance spectroscopy in the visible wavelengths. The system is designed for measurements in deep brain structures by stereotaxically implanting the 200 μm-core fiber probe into the tissue of interest. Monte Carlo (MC) simulations were used to estimate the measurement tissue volume between 0.02-0.03 mm(3). Experiments in an optical phantom indicated the system had a root mean squared error (RMSE) of 4...
November 1, 2016: Biomedical Optics Express
Phong Phan, David Highton, Jonathan Lai, Martin Smith, Clare Elwell, Ilias Tachtsidis
We present a multi-channel, multi-distance broadband near-infrared spectroscopy (NIRS) system with the capability of measuring changes in haemoglobin concentrations (Δ[HbO2], Δ[HHb]), oxidation state of cytochrome-c-oxidase (Δ[oxCCO]) and tissue oxygen saturation (TOI) in the adult human brain. The main components of the instrument are two customized spectrographs and two light sources. Each spectrograph is lens-based to improve light throughput, has a grating enhanced to optimise reflection in the near-infrared (NIR) spectral region and uses a front illuminated cooled CCD camera (-70° C) with a square chip dimension of 12...
November 1, 2016: Biomedical Optics Express
Adrien Lücker, Timothy W Secomb, Bruno Weber, Patrick Jenny
OBJECTIVE: Oxygen transport to parenchymal cells occurs mainly at the microvascular level, and depends on convective red blood cell (RBC) flux, which is proportional in an individual capillary to the product of capillary hematocrit and red blood cell velocity. This study investigates the relative influence of these two factors on tissue oxygen partial pressure (PO2 ). METHODS: A simple analytical model is used to quantify the respective influences of hematocrit, RBC velocity and flow on tissue oxygenation around capillaries...
November 28, 2016: Microcirculation: the Official Journal of the Microcirculatory Society, Inc
Nicolas Dzamko, Amanda Gysbers, Gayathri Perera, Anita Bahar, Amrita Shankar, Jianqun Gao, YuHong Fu, Glenda M Halliday
Inflammation is likely a key contributor to the pathogenesis of Parkinson's disease (PD), a progressively debilitating neurodegenerative disease that is accompanied by a pathological accumulation of the α-synuclein protein in a staged manner through the brain. What leads to the accumulation of α-synuclein in PD and how this relates to inflammatory pathways, however, is not entirely clear. Toll-like receptor (TLR) signaling is a major pathway mediating inflammation and, in particular, TLR2 is increasingly being implicated in PD...
November 25, 2016: Acta Neuropathologica
Jan Malik, Jaroslav Kudlicka, Jana Lachmanova, Anna Valerianova, Katarina Rocinova, Magdalena Bartkova, Vladimir Tesar
BACKGROUND: Cognitive deficit is a common problem in end-stage renal disease (ESRD) patients. Ultrafiltration and hemodialysis lead to profound hemodynamic changes. The aim of this pilot study was to describe brain and hand oxygenation values in ESRD patients and their changes during hemodialysis. METHODS: Twenty-seven patients treated by chronic hemodialysis and 17 controls patients of the same age were included in the study. Regional saturation of oxygen (SrO2) was measured at the brain frontal lobe and at the hand with dialysis access using the INVOS 5100C...
November 22, 2016: Journal of Vascular Access
B Lemasson, N Pannetier, N Coquery, Ligia S B Boisserand, Nora Collomb, N Schuff, M Moseley, G Zaharchuk, E L Barbier, T Christen
In this study, we evaluated an MRI fingerprinting approach (MRvF) designed to provide high-resolution parametric maps of the microvascular architecture (i.e., blood volume fraction, vessel diameter) and function (blood oxygenation) simultaneously. The method was tested in rats (n = 115), divided in 3 models: brain tumors (9 L, C6, F98), permanent stroke, and a control group of healthy animals. We showed that fingerprinting can robustly distinguish between healthy and pathological brain tissues with different behaviors in tumor and stroke models...
November 24, 2016: Scientific Reports
Gareth Morris, Premysl Jiruska, John G R Jefferys, Andrew D Powell
Highlights Simultaneous epileptiform LFPs and single-cell activity can be recorded in the membrane chamber.Interneuron firing can be linked to epileptiform high frequency activity.Fast ripples, unique to chronic epilepsy, can be modeled in ex vivo tissue from TeNT-treated rats. Traditionally, visually-guided patch clamp in brain slices using submerged recording conditions has been required to characterize the activity of individual neurons. However, due to limited oxygen availability, submerged conditions truncate fast network oscillations including epileptiform activity...
2016: Frontiers in Neuroscience
Wolf-Dieter Heiss, Olivier Zaro Weber
The concept of the ischemic penumbra was formulated based on animal experiments showing functional impairment and electrophysiological disturbances with decreasing flow to the brain below defined values (the threshold for function) and irreversible tissue damage with blood supply further decreased (the threshold for infarction). The perfusion range between these thresholds was termed "penumbra", and restitution of flow above the functional threshold was able to reverse the deficits without permanent damage...
November 22, 2016: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Alexander Caicedo, Carolina Varon, Borbala Hunyadi, Maria Papademetriou, Ilias Tachtsidis, Sabine Van Huffel
Clinical data is comprised by a large number of synchronously collected biomedical signals that are measured at different locations. Deciphering the interrelationships of these signals can yield important information about their dependence providing some useful clinical diagnostic data. For instance, by computing the coupling between Near-Infrared Spectroscopy signals (NIRS) and systemic variables the status of the hemodynamic regulation mechanisms can be assessed. In this paper we introduce an algorithm for the decomposition of NIRS signals into additive components...
2016: Frontiers in Physiology
Jingyuan E Chen, Gary Glover, Hesamoddin Jahanian
Recently, emerging studies have demonstrated the existence of brain resting state (RS) spontaneous activity at frequencies higher than the conventional 0.1 Hz. A few groups utilizing accelerated acquisitions have reported persisting signals beyond 1 Hz, which seems too high to be accommodated by the sluggish hemodynamic process underpinning blood-oxygen-level dependent contrasts (the upper limit of the canonical model is ~ 0.3 Hz). It is thus questionable whether the observed high-frequency (HF) functional connectivity (FC) originates from alternative mechanisms (e...
November 22, 2016: Brain Connectivity
Rania Abutarboush, Biswajit K Saha, Saad H Mullah, Francoise G Arnaud, Ashraful Haque, Chioma Aligbe, Georgina Pappas, Charles R Auker, Richard M McCarron, Paula F Moon-Massat, Anke H Scultetus
Oxygen-carrying perfluorocarbon (PFC) fluids have the potential to increase tissue oxygenation during hypoxic states and to reduce ischemic cell death. Regulatory approval of oxygen therapeutics was halted due to concerns over vasoconstrictive side effects. The goal of this study was to assess the potential vasoactive properties of Perftoran by measuring brain pial arteriolar diameters in a healthy rat model. Perftoran, crystalloid (saline) or colloid (Hextend) solutions were administered as four sequential 30 min intravenous (IV) infusions, thus allowing an evaluation of cumulative dose-dependent effects...
November 18, 2016: Journal of Functional Biomaterials
Héloïse Auger, Louis Bherer, Étienne Boucher, Richard Hoge, Frédéric Lesage, Mathieu Dehaes
Fitness is known to have beneficial effects on brain anatomy and function. However, the understanding of mechanisms underlying immediate and long-term neurophysiological changes due to exercise is currently incomplete due to the lack of tools to investigate brain function during physical activity. In this study, we used time-domain near infrared spectroscopy (TD-NIRS) to quantify and discriminate extra-cerebral and cerebral hemoglobin concentrations and oxygen saturation (SO2) in young adults at rest and during incremental intensity exercise...
October 1, 2016: Biomedical Optics Express
Laurent Chazalviel, Jean-Eric Blatteau, Nicolas Vallée, Jean-Jacques Risso, Stéphane Besnard, Jacques H Abraini
Normobaric oxygen (NBO) and hyperbaric oxygen (HBO) are emerging as a possible co-treatment of acute ischemic stroke. Both have been shown to reduce infarct volume, to improve neurologic outcome, to promote endogenous tissue plasminogen activator-induced thrombolysis and cerebral blood flow, and to improve tissue oxygenation through oxygen diffusion in the ischemic areas, thereby questioning the interest of HBO compared to NBO. In the present study, in order to investigate and compare the oxygen diffusion effects of NBO and HBO on acute ischemic stroke independently of their effects at the vascular level, we used acute brain slices exposed to oxygen and glucose deprivation, an ex vivo model of brain ischemia that allows investigating the acute effects of NBO (partial pressure of oxygen (pO2) = 1 atmospheres absolute (ATA) = 0...
July 2016: Medical Gas Research
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