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https://www.readbyqxmd.com/read/28844181/changes-in-pressure-hemodynamics-and-metabolism-within-the-spinal-cord-during-the-first-7-days-after-injury-using-a-porcine-model
#1
Femke Streijger, Kitty So, Neda Manouchehri, Jae H T Lee, Elena B Okon, Katelyn Shortt, So-Eun Kim, Kurt McInnes, Peter Cripton, Brian K Kwon
Traumatic spinal cord injury (SCI) triggers many perturbations within the injured cord, such as decreased perfusion, reduced tissue oxygenation, increased hydrostatic pressure, and disrupted bioenergetics. While much attention is directed to neuroprotective interventions that might alleviate these early pathophysiologic responses to traumatic injury, the temporo-spatial characteristics of these responses within the injured cord are not well documented. In this study, we utilized our Yucatan mini-pig model of traumatic SCI to characterize intraparenchymal hemodynamic and metabolic changes within the spinal cord for 1 week post-injury...
September 14, 2017: Journal of Neurotrauma
https://www.readbyqxmd.com/read/28820467/aquaporin-4-functionality-and-virchow-robin-space-water-dynamics-physiological-model-for-neurovascular-coupling-and-glymphatic-flow
#2
REVIEW
Tsutomu Nakada, Ingrid L Kwee, Hironaka Igarashi, Yuji Suzuki
The unique properties of brain capillary endothelium, critical in maintaining the blood-brain barrier (BBB) and restricting water permeability across the BBB, have important consequences on fluid hydrodynamics inside the BBB hereto inadequately recognized. Recent studies indicate that the mechanisms underlying brain water dynamics are distinct from systemic tissue water dynamics. Hydrostatic pressure created by the systolic force of the heart, essential for interstitial circulation and lymphatic flow in systemic circulation, is effectively impeded from propagating into the interstitial fluid inside the BBB by the tightly sealed endothelium of brain capillaries...
August 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28727900/head-midline-position-for-preventing-the-occurrence-or-extension-of-germinal-matrix-intraventricular-hemorrhage-in-preterm-infants
#3
REVIEW
Olga Romantsik, Maria Grazia Calevo, Matteo Bruschettini
BACKGROUND: Preterm birth is known to constitute the major risk factor for development of germinal matrix-intraventricular hemorrhage (GM-IVH). Head position may affect cerebral hemodynamics and thus may be involved indirectly in development of GM-IVH. Turning the head toward one side may functionally occlude jugular venous drainage on the ipsilateral side while increasing intracranial pressure and cerebral blood volume. Thus, it has been suggested that cerebral venous pressure is reduced and hydrostatic brain drainage improved if the patient is in supine midline position with the bed tilted 30°...
July 20, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28704262/effect-of-upper-body-position-on-arterial-stiffness-influence-of-hydrostatic-pressure-and-autonomic-function
#4
Elizabeth C Schroeder, Alexander J Rosenberg, Thessa I M Hilgenkamp, Daniel W White, Tracy Baynard, Bo Fernhall
OBJECTIVE: To evaluate changes in arterial stiffness with positional change and whether the stiffness changes are due to hydrostatic pressure alone or if physiological changes in vasoconstriction of the conduit arteries play a role in the modulation of arterial stiffness. METHODS: Thirty participants' (male = 15, 24 ± 4 years) upper bodies were positioned at 0, 45, and 72° angles. Pulse wave velocity (PWV), cardio-ankle vascular index, carotid beta-stiffness index, carotid blood pressure (cBP), and carotid diameters were measured at each position...
July 12, 2017: Journal of Hypertension
https://www.readbyqxmd.com/read/28674514/aspects-on-the-physiological-and-biochemical-foundations-of-neurocritical-care
#5
REVIEW
Carl-Henrik Nordström, Lars-Owe Koskinen, Magnus Olivecrona
Neurocritical care (NCC) is a branch of intensive care medicine characterized by specific physiological and biochemical monitoring techniques necessary for identifying cerebral adverse events and for evaluating specific therapies. Information is primarily obtained from physiological variables related to intracranial pressure (ICP) and cerebral blood flow (CBF) and from physiological and biochemical variables related to cerebral energy metabolism. Non-surgical therapies developed for treating increased ICP are based on knowledge regarding transport of water across the intact and injured blood-brain barrier (BBB) and the regulation of CBF...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28663380/bone-microvascular-flow-differs-from-skin-microvascular-flow-in-response-to-head-down-tilt
#6
Michelle Howden, Jamila H Siamwala, Alan R Hargens
Loss of hydrostatic pressures in microgravity may alter skin and bone microvascular flows in the lower extremities and may potentially reduce wound healing and bone fracture repair. The purpose of this study was to determine the rate at which skin and bone microvascular flows respond to head down tilt (HDT). We hypothesized that microvascular flows in tibial bone and overlying skin would increase at different rates during HDT. Tibial bone and skin microvascular flows were measured simultaneously using photoplethysmography (PPG) in a total of 17 subjects during sitting (control posture), supine, 6° HDT, 15° HDT, and 30° HDT postures in random order...
June 29, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28646097/highly-suggestive-preliminary-evidence-that-the-renal-interstitium-contracts-in%C3%A2-vivo
#7
Omar Flores-Sandoval, María Eugenia Sánchez-Briones, Juan F López-Rodríguez, Miriam Z Calvo-Turrubiartes, Lilia Llamazares-Azuara, Manuel Rodríguez-Martínez
To learn more about controlling renal interstitial hydrostatic pressure (RIHP), we assessed its response to renal medullary direct interstitial volume expansion (rmDIVE = 100 μL bolus infusion/30 sec). Three experimental series (S) were performed in hydropenic, anesthetized, right-nephrectomized, acute left renal-denervated and renal perfusion pressure-controlled rats randomly assigned to groups in each S. S1: Rats without hormonal clamp were contrasted before and after rmDIVE induced via 0.9% saline solution bolus (SS group) or 2% albumin in SS bolus (2% ALB + SS group)...
June 2017: Physiological Reports
https://www.readbyqxmd.com/read/28554506/bion-m-1-first-continuous-blood-pressure-monitoring-in-mice-during-a-30-day-spaceflight
#8
Alexander Andreev-Andrievskiy, Anfisa Popova, Jean-Christophe Lloret, Patrick Aubry, Anatoliy Borovik, Daria Tsvirkun, Olga Vinogradova, Eugeniy Ilyin, Guillemette Gauquelin-Koch, Claude Gharib, Marc-Antoine Custaud
Animals are an essential component of space exploration and have been used to demonstrate that weightlessness does not disrupt essential physiological functions. They can also contribute to space research as models of weightlessness-induced changes in humans. Animal research was an integral component of the 30-day automated Russian biosatellite Bion-M 1 space mission. The aim of the hemodynamic experiment was to estimate cardiovascular function in mice, a species roughly 3000 times smaller than humans, during prolonged spaceflight and post-flight recovery, particularly, to investigate if mice display signs of cardiovascular deconditioning...
May 2017: Life Sciences in Space Research
https://www.readbyqxmd.com/read/28540405/mechanical-stimuli-modulate-intracellular-calcium-oscillations-a-pathological-model-without-chemical-cues
#9
Yan Ru Wu, Yun Gyeong Kang, Ji Won Shin, Mi Jin Kim, Jung-Woog Shin
OBJECTIVE: To control the oscillatory behavior of the intracellular calcium ([Ca(2+)]i) concentration in endothelial cells via mechanical factors (i.e., various hydrostatic pressures) because [Ca(2+)]i in these cells is affected by blood pressure. RESULTS: Quantitative analyses based on real-time imaging showed that [Ca(2+)]i oscillation frequency and relative concentration increased significantly when 200 mm Hg pressure, mimicking hypertension, was applied for >10 min...
May 24, 2017: Biotechnology Letters
https://www.readbyqxmd.com/read/28463576/advances-in-application-of-mechanical-stimuli-in-bioreactors-for-cartilage-tissue-engineering
#10
Ke Li, Chunqiu Zhang, Lulu Qiu, Lilan Gao, Xizheng Zhang
Articular cartilage (AC) is the weight-bearing tissue in diarthroses. It lacks the capacity for self-healing once there are injuries or diseases due to its avascularity. With the development of tissue engineering, repairing cartilage defects through transplantation of engineered cartilage that closely matches properties of native cartilage has become a new option for curing cartilage diseases. The main hurdle for clinical application of engineered cartilage is how to develop functional cartilage constructs for mass production in a credible way...
August 2017: Tissue Engineering. Part B, Reviews
https://www.readbyqxmd.com/read/28413031/matrix-metalloproteinases-in-remodeling-of-lower-extremity-veins-and-chronic-venous-disease
#11
REVIEW
Yunfei Chen, Wei Peng, Joseph D Raffetto, Raouf A Khalil
The veins of the lower extremity are equipped with efficient wall, contractile vascular smooth muscle (VSM), and competent valves in order to withstand the high venous hydrostatic pressure in the lower limb and allow unidirectional movement of deoxygenated blood toward the heart. The vein wall structure and function are in part regulated by matrix metalloproteinases (MMPs). MMPs are zinc-dependent endopeptidases that are secreted as inactive pro-MMPs by different cells in the venous wall including fibroblasts, VSM, and leukocytes...
2017: Progress in Molecular Biology and Translational Science
https://www.readbyqxmd.com/read/28408434/renal-and-vascular-effects-of-uric-acid-lowering-in-normouricemic-patients-with-uncomplicated-type-1-diabetes
#12
Yuliya Lytvyn, Ronnie Har, Amy Locke, Vesta Lai, Derek Fong, Andrew Advani, Bruce A Perkins, David Z I Cherney
Higher plasma uric acid (PUA) levels are associated with lower glomerular filtration rate (GFR) and higher blood pressure (BP) in patients with type 1 diabetes (T1D). Our aim was to determine the impact of PUA lowering on renal and vascular function in patients with uncomplicated T1D. T1D patients (n = 49) were studied under euglycemic and hyperglycemic conditions at baseline and after PUA lowering with febuxostat (FBX) for 8 weeks. Healthy control subjects were studied under normoglycemic conditions (n = 24)...
July 2017: Diabetes
https://www.readbyqxmd.com/read/28382948/high-hydrostatic-pressure-specifically-affects-molecular-dynamics-and-shape-of-low-density-lipoprotein-particles
#13
M Golub, B Lehofer, N Martinez, J Ollivier, J Kohlbrecher, R Prassl, J Peters
Lipid composition of human low-density lipoprotein (LDL) and its physicochemical characteristics are relevant for proper functioning of lipid transport in the blood circulation. To explore dynamical and structural features of LDL particles with either a normal or a triglyceride-rich lipid composition we combined coherent and incoherent neutron scattering methods. The investigations were carried out under high hydrostatic pressure (HHP), which is a versatile tool to study the physicochemical behavior of biomolecules in solution at a molecular level...
April 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28373858/enhanced-cholinergic-activity-improves-cerebral-blood-flow-during-orthostatic-stress
#14
Jorge M Serrador, Roy Freeman
Cerebral blood flow (CBF) and consequently orthostatic tolerance when upright depends on dilation of the cerebral vasculature in the face of reduced perfusion pressure associated with the hydrostatic gradient. However, it is still unclear if cholinergic activation plays a role in this dilation. To determine if enhancing central cholinergic activity with the centrally acting acetylcholinesterase inhibitor, physostigmine would increase CBF when upright compared to the peripherally acting acetylcholinesterase inhibitor, neostigmine, or saline...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28357825/the-prevalence-of-electrocardiogram-abnormalities-in-professional-divers
#15
Ali Erdal Gunes, Maide Cimsit
BACKGROUND: The underwater environment presents physiological challenges for the cardiovascular, renal and pulmonary systems. Increases in external hydrostatic pressure reduce the capacity of the venous compartment and cause blood to move toward the lung. The aim of this study was to evaluate retrospectively electrocardiographic (ECG) changes in a cohort of professional divers. METHODS: Between January 2009 and January 2012, 225 randomly selected professional divers, 204 male (91%) and 21 female (9%) attended our clinic for their biannual diving medical assessment...
March 2017: Diving and Hyperbaric Medicine: the Journal of the South Pacific Underwater Medicine Society
https://www.readbyqxmd.com/read/28351041/mechanisms-of-retinal-fluid-accumulation-and-blood-retinal-barrier-breakdown
#16
REVIEW
José Cunha-Vaz
Macular edema is the swelling of the central portion of the human retina and it is associated with increased retinal thickness. It can be simply defined as an excess of fluid within the retinal tissue. It must be realized that the normal retina possesses a functional extracellular space. With regard to the extracellular volume of the retina, there have been few physiologic studies, but there are reported values of 24.8% for the cerebrum and 23.6% for the cerebellum. It is accepted that the retinal extracellular space is similar to the brain...
2017: Developments in Ophthalmology
https://www.readbyqxmd.com/read/28287428/an-experimental-study-of-the-effects-of-external-physiological-parameters-on-the-photoplethysmography-signals-in-the-context-of-local-blood-pressure-hydrostatic-pressure-changes
#17
Hongwei Yuan, Sven Poeggel, Thomas Newe, Elfed Lewis, Charusluk Viphavakit, Gabriel Leen
A comprehensive study of the effect of a wide range of controlled human subject motion on Photoplethysmographic signals is reported. The investigation includes testing of two separate groups of 5 and 18 subjects who were asked to undertake set exercises whilst simultaneously monitoring a wide range of physiological parameters including Breathing Rate, Heart Rate and Localised Blood Pressure using commercial clinical sensing systems. The unique finger mounted PPG probe equipped with miniature three axis accelerometers for undertaking this investigation was a purpose built in-house version which is designed to facilitate reproducible application to a wide range of human subjects and the study of motion...
March 10, 2017: Sensors
https://www.readbyqxmd.com/read/28273941/arterial-graft-with-elastic-layer-structure-grown-from-cells
#18
Utako Yokoyama, Yuta Tonooka, Ryoma Koretake, Taisuke Akimoto, Yuki Gonda, Junichi Saito, Masanari Umemura, Takayuki Fujita, Shinya Sakuma, Fumihito Arai, Makoto Kaneko, Yoshihiro Ishikawa
Shortage of autologous blood vessel sources and disadvantages of synthetic grafts have increased interest in the development of tissue-engineered vascular grafts. However, tunica media, which comprises layered elastic laminae, largely determines arterial elasticity, and is difficult to synthesize. Here, we describe a method for fabrication of arterial grafts with elastic layer structure from cultured human vascular SMCs by periodic exposure to extremely high hydrostatic pressure (HP) during repeated cell seeding...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28258771/acoustic-behavior-of-halobacterium-salinarum-gas-vesicles-in-the-high-frequency-range-experiments-and-modeling
#19
Emmanuel Cherin, Johan M Melis, Raymond W Bourdeau, Melissa Yin, Dennis M Kochmann, F Stuart Foster, Mikhail G Shapiro
Gas vesicles (GVs) are a new and unique class of biologically derived ultrasound contrast agents with sub-micron size whose acoustic properties have not been fully elucidated. In this study, we investigated the acoustic collapse pressure and behavior of Halobacterium salinarum gas vesicles at transmit center frequencies ranging from 12.5 to 27.5 MHz. The acoustic collapse pressure was found to be above 550 kPa at all frequencies, nine-fold higher than the critical pressure observed under hydrostatic conditions...
May 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28242827/postural-effects-on-cerebral-blood-flow-and-autoregulation
#20
Zachary K Garrett, James Pearson, Andrew W Subudhi
Cerebral autoregulation (CA) is thought to maintain relatively constant cerebral blood flow (CBF) across normal blood pressures. To determine if postural changes alter CA, we measured cerebral blood flow velocity (CBFv) in the middle cerebral arteries, mean arterial blood pressure (MABP), cardiac output (Q), and end-tidal carbon dioxide (PETCO2) in 18 healthy individuals (11 female and seven male; 26 ± 9 years) during repeated periods of supine and seated rest. Multiple regression was used to evaluate the influence of PETCO2, MABP, Q, and hydrostatic pressure on CBFv...
February 2017: Physiological Reports
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