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hydrostatic pressure in blood

Allison P Anderson, Joseph S Butterfield, Prem S Subramanian, Torin K Clark
INTRODUCTION: Artificial gravity (AG) has been proposed as a countermeasure to spaceflight associated neuro-ocular syndrome (SANS). The etiology of SANS is unknown, but mimicking gravitational loading through AG may mitigate these negative adaptations. METHODS: Seventeen subjects (9M, 8F, 18-32 years) were analyzed in four experimental conditions: 1) Standing, 2) Supine, 3) AG with the center of rotation at the eye (AGEC), 4) AG with 2G's at the feet (AG2G). In both AG conditions, subjects were spun to produce 1G at their center of mass...
May 10, 2018: Journal of Applied Physiology
Franz Lahnsteiner, Manfred Kletzl
The study tested the efficiency of hydrostatic pressure triploidization methods for Salmo trutta f. lacustris and Salvelinus umbla and investigated the effects on survival rate, skeletal malformation, and on morphometrics and cellular composition of gills, spleen, liver, kidney, intestine, and blood. In Salmo trutta f. lacustris a 100% triploidy rate in combination with high larvae survival rate (80% in comparison to control) was obtained when treating eggs with a pressure of 66 × 103  kPa 360 °C temperature minutes (CTM) post fertilization for 5 min, in Salvelinus umbla with a similar pressure after 270 CTM...
April 24, 2018: Theriogenology
Olga Frlic, Alenka Seliškar, Aleksandra Domanjko Petrič, Rok Blagus, George Heigenhauser, Modest Vengust
General anesthesia (GA) can cause abnormal lung fluid redistribution. Pulmonary circulation transvascular fluid fluxes ( J VA ) are attributed to changes in hydrostatic forces and erythrocyte volume (EV) regulation. Despite the very low hydraulic conductance of pulmonary microvasculature it is possible that GA may affect hydrostatic forces through changes in pulmonary vascular resistance (PVR), and EV through alteration of erythrocyte transmembrane ion fluxes ( ion J VA ). Furosemide (Fur) was also used because of its potential to affect pulmonary hydrostatic forces and ion J VA ...
2018: Frontiers in Physiology
Heather Reilly, Louise M Lane, Mikel Egaña
PURPOSE: Age-related exercising leg blood flow (LBF) responses during dynamic knee-extension exercise and forearm blood flow responses during handgrip exercise are preserved in normally active men but attenuated in activity-matched women. We explored whether these age- and sex-specific effects are also apparent during isometric calf plantar-flexion incremental exercise. METHODS: Normally active young men (YM, n = 15, 24 ± 2 years), young women (YW, n = 8, 22 ± 1 years), older men (OM, n = 13, 70 ± 7 years) and older women (OW, n = 10, 64 ± 7 years) were tested...
March 3, 2018: European Journal of Applied Physiology
Monika Zielinska-Krawczyk, Rafal Krenke, Elzbieta M Grabczak, Richard W Light
Subatmospheric pleural pressure (Ppl), which is approximately -3 to -5 cmH2 O at functional residual capacity (FRC) makes pleura a unique organ in the human body. The negative Ppl is critical for maintaining the lungs in a properly inflated state and for proper blood circulation within the thorax. Significant and sudden pleural pressure changes associated with major pleural pathologies, as well as therapeutic interventions may be associated with life-threatening complications. The pleural pressure may show two different values depending on the measurement method applied...
March 2018: Respiratory Medicine
Fernando J Sialana, Gabriel Schneebauer, Ana Paunkov, Bernd Pelster, Gert Lubec
The swim bladder of a fish is a vital organ that with gas gland cells in the swim bladder wall enables key physiological functions including buoyancy regulation in the face of different hydrostatic pressures. Specific gas gland cells produce and secrete acidic metabolites into the blood in order to reduce the physical solubility of gases and blood gas transport capacity for regulating the volume of the swim bladder. Transcriptomic analyses have provided evidence at the RNA level but no specific studies at the protein level have been carried out so far...
April 2018: Proteomics
Daniel Schneditz, Georgios Sarikakis, Maria Kontodima, Notburga Sauseng
The aim of this study was to examine the relationship between hydrostatic trans-membrane pressure (TMPh ) and colloid osmotic pressure (COP) in low-flux (LF) and high-flux (HF) dialyzers. Hydrostatic pressures were measured in dialyzers distinguished by their ultrafiltration coefficient Kuf (16 and 85 mL/h/mm Hg) under constant dialysate flow and variable blood flow (Qb ) ranging from 0 to 400 mL/min using (i) alginate (70 kDa) dissolved in dialysate, (ii) diluted, undiluted, and concentrated plasma, or (iii) whole blood at different hematocrit, all in absence of ultrafiltration (UF)...
January 17, 2018: Artificial Organs
Femke Streijger, Kitty So, Neda Manouchehri, Ana Gheorghe, Elena B Okon, Ryan M Chan, Benjamin Ng, Katelyn Shortt, Mypinder S Sekhon, Donald E Griesdale, Brian K Kwon
Current clinical guidelines recommend elevating the mean arterial blood pressure (MAP) to increase spinal cord perfusion in patients with acute spinal cord injury (SCI). This is typically achieved with vasopressors such as norepinephrine (NE) and phenylephrine (PE). These drugs differ in their pharmacological properties and potentially have different effects on spinal cord blood flow (SCBF), oxygenation (PO2 ), and downstream metabolism after injury. Using a porcine model of thoracic SCI, we evaluated how these vasopressors influenced intraparenchymal SCBF, PO2 , hydrostatic pressure, and metabolism within the spinal cord adjacent to the injury site...
March 28, 2018: Journal of Neurotrauma
Chor Ho Jo, Sua Kim, Il Hwan Oh, Joon-Sung Park, Gheun-Ho Kim
BACKGROUND/AIMS: Altered pressure natriuresis is an important mechanism of hypertension, but it remains elusive at the molecular level. We hypothesized that in the kidney, tight junctions (TJs) may have a role in pressure natriuresis because paracellular NaCl transport affects interstitial hydrostatic pressure. METHODS: To assess the association of salt-sensitive hypertension with altered renal TJ protein expression, Dahl salt-sensitive (SS) and salt-resistant (SR) rats were put on an 8% NaCl-containing rodent diet for 4 weeks...
2017: Kidney & Blood Pressure Research
Ananya Tripathi, Yurie Obata, Pavel Ruzankin, Narwan Askaryar, Dan E Berkowitz, Jochen Steppan, Viachaslau Barodka
Background: Constant blood flow despite changes in blood pressure, a phenomenon called autoregulation, has been demonstrated for various organ systems. We hypothesized that by changing hydrostatic pressures in peripheral arteries, we can establish these limits of autoregulation in peripheral arteries based on local pulse wave velocity (PWV). Methods: Electrocardiogram and plethysmograph waveforms were recorded at the left and right index fingers in 18 healthy volunteers. Each subject changed their left arm position, keeping the right arm stationary...
2017: Frontiers in Physiology
Steven De Abreu, Liubov Amirova, Ronan Murphy, Robert Wallace, Laura Twomey, Guillemette Gauquelin-Koch, Veronique Raverot, Françoise Larcher, Marc-Antoine Custaud, Nastassia Navasiolava
Dry immersion (DI) is a Russian-developed, ground-based model to study the physiological effects of microgravity. It accurately reproduces environmental conditions of weightlessness, such as enhanced physical inactivity, suppression of hydrostatic pressure and supportlessness. We aimed to study the integrative physiological responses to a 3-day strict DI protocol in 12 healthy men, and to assess the extent of multi-system deconditioning. We recorded general clinical data, biological data and evaluated body fluid changes...
2017: Frontiers in Physiology
Po-Ling Kuo, Hao-Dinh Phung
Hepatic stellate cells (HSCs) play a crucial role in the development of liver fibrosis which is characterized by massive tissue scarring, elevated hepatic sinusoidal pressure, and portal hypertension. However, while a multitude of chemical factors have been investigated in the pathogenesis of liver fibrosis, physical factors such as elevated hydrostatic pressure and shear stress caused by blood flow in sinusoids remain unclear. In this study, we developed a three-dimensional (3D) cell culture microfluidic platform that mimics the physical environments of hepatic sinusoids to investigate the effects of elevated hydrostatic pressure on HSCs phenotypes...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
W Kang, A R Clark, M H Tawhai
Gravity and matched airway/vascular tree geometries are both hypothesized to be key contributors to ventilation-perfusion (V̇/Q̇) matching in the lung, but their relative contributions are challenging to quantify experimentally. We used a structure-based model to conduct an analysis of the relative contributions of tissue deformation (the "Slinky" effect), other gravitational mechanisms (weight of blood and gravitational gradient in tissue elastic recoil), and matched airway and arterial tree geometry to V̇/Q̇ matching and therefore to total lung oxygen exchange...
January 1, 2018: Journal of Applied Physiology
Benjamin Frey, Michael Rückert, Lisa Deloch, Paul F Rühle, Anja Derer, Rainer Fietkau, Udo S Gaipl
Ionizing radiation is often regarded as an element of danger. But, danger responses on the cellular and molecular level are often beneficial with regard to the induction of anti-tumor immunity and for amelioration of inflammation. We outline how in dependence of radiation dose and fraction, radiation itself-and especially in combination with immune modulators-impacts on the innate and adaptive immune system. Focus is set on radiation-induced changes of the tumor cell phenotype and the cellular microenvironment including immunogenic cancer cell death...
November 2017: Immunological Reviews
Femke Streijger, Kitty So, Neda Manouchehri, Seth Tigchelaar, 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...
December 15, 2017: Journal of Neurotrauma
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
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
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
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
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 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...
October 1, 2017: Journal of Applied Physiology
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