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https://www.readbyqxmd.com/read/28540405/mechanical-stimuli-modulate-intracellular-calcium-oscillations-a-pathological-model-without-chemical-cues
#1
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
#2
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...
May 24, 2017: Tissue Engineering. Part B, Reviews
https://www.readbyqxmd.com/read/28413031/matrix-metalloproteinases-in-remodeling-of-lower-extremity-veins-and-chronic-venous-disease
#3
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
#4
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 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 eu- and hyperglycemic conditions at baseline and after PUA lowering with febuxostat (FBX) for 8 weeks. Healthy controls (HC) were studied under normoglycemic conditions (n=24). PUA, GFR (inulin), effective renal plasma flow (ERPF, paraaminohippurate), BP and hemodynamic responses to an infusion of angiotensin II (assessment of intrarenal RAAS) were measured pre- and post-FBX...
April 13, 2017: Diabetes
https://www.readbyqxmd.com/read/28382948/high-hydrostatic-pressure-specifically-affects-molecular-dynamics-and-shape-of-low-density-lipoprotein-particles
#5
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
#6
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
#7
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
#8
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
#9
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
#10
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
#11
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
#12
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
https://www.readbyqxmd.com/read/28228405/inhibition-of-romk-blocks-macula-densa-tubuloglomerular-feedback-yet-causes-renal-vasoconstriction-in-anesthetized-rats
#13
Magali Araujo, William J Welch, Xiaoyan Zhou, Kathleen Sullivan, Shawn Walsh, Alexander Pasternak, Christopher S Wilcox
The Na+/K+/2Cl- cotransporter (NKCC2) on the loop of Henle is the site of action of furosemide. Since outer medullary potassium channel (ROMK) inhibitors prevent reabsorption by NKCC2, we tested the hypothesis that ROMK inhibition with a novel, selective ROMK inhibitor (Compound C) blocks tubuloglomerular feedback (TGF) and reduces vascular resistance. Loop perfusion of either ROMK inhibitor or furosemide caused dose-dependent blunting of TGF, but the response to furosemide was 10-fold more sensitive (IC50= 10-6M for furosemide and IC50=10-5M for Compound C)...
February 22, 2017: American Journal of Physiology. Renal Physiology
https://www.readbyqxmd.com/read/28209177/is-posture-related-craniospinal-compliance-shift-caused-by-jugular-vein-collapse-a-theoretical-analysis
#14
Manuel Gehlen, Vartan Kurtcuoglu, Marianne Schmid Daners
BACKGROUND: Postural changes are related to changes in cerebrospinal fluid (CSF) dynamics. While sitting up leads to a decrease in cranial CSF pressure, it also causes shifts in the craniospinal CSF volume and compliance distribution. We hypothesized that jugular vein collapse in upright posture is a major contributor to these shifts in CSF volume and compliance. METHODS: To test this hypothesis, we implemented a mathematical lumped-parameter model of the CSF system and the relevant parts of the cardiovascular system...
February 16, 2017: Fluids and Barriers of the CNS
https://www.readbyqxmd.com/read/28152535/the-blood-retinal-barrier-in-the-management-of-retinal-disease-euretina-award-lecture
#15
José Cunha-Vaz
Retinal diseases are the main causes of blindness in the Western world. Diabetic retinopathy and age-related macular degeneration continue to increase in prevalence and as main causes of vision loss. Intravitreal anti-VEGF and steroid injections have raised new expectations for their successful treatment. These agents act by stabilizing the blood-retinal barrier (BRB). Our group defined the BRB by identifying for the first time the tight junctions that unite retinal endothelial cells and are the basis for the inner BRB, an observation later confirmed in retinal pigment epithelial cells and in brain vessels...
2017: Ophthalmologica. Journal International D'ophtalmologie
https://www.readbyqxmd.com/read/28130834/evaluation-of-small-diameter-vascular-grafts-reconstructed-from-decellularized-aorta-sheets
#16
Jun Negishi, Yoshihide Hashimoto, Akitatsu Yamashita, Yongwei Zhang, Tsuyoshi Kimura, Akio Kishida, Seiichi Funamoto
Following small-diameter vascular grafting, blood vessels fail to retain excellent antithrombotic function and therefore require application of antithrombogenic drugs. We have previously reported early attachment of endothelial cells to the luminal surface of high hydrostatic pressure (HHP)-decellularized arteries after transplantation. In addition, the graft retained antithrombotic function by endothelialization and remained open for several weeks. To fabricate tube grafts of optimal size and shape for small-diameter vascular grafting, we evaluated decellularized porcine aorta sheets as a suitable antithrombogenic material...
May 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28017950/-effects-of-exercise-on-joints
#17
Hideki Moriyama
Joints are composed of several different tissues(cartilage, capsule, meniscus, and ligament), and articular cartilage plays an important role in maintaining mechanical competence during exercise. Weight-bearing exercise has several benefit, including improved blood and synovial fluid circulation in a given joint. Consistent moderate activities facilitate cycles of anabolism and catabolism. Mechanical stresses are crucial for the maintenance of the morphologic and functional integrity of articular cartilage...
2017: Clinical Calcium
https://www.readbyqxmd.com/read/28003847/in-vitro-protective-effect-of-phikud-navakot-extraction-on-erythrocyte
#18
Kanchana Kengkoom, Sumate Ampawong
Phikud Navakot (PN), Thai herbal remedy in National List of Essential Medicines, has been claimed to reduce many cardiovascular symptoms especially dizziness and fainting. Apart from blood supply, erythrocyte morphology, in both shape and size, is one of the main consideration factors in cardiovascular diseases and may be affected by vascular oxidative stress. However, little is known about antioxidative property of PN on erythrocyte to preserve red blood cell integrity. In this study, 1,000 μM hydrogen peroxide-induced oxidative stress was conducted on sheep erythrocyte...
2016: Evidence-based Complementary and Alternative Medicine: ECAM
https://www.readbyqxmd.com/read/27799072/fluid-and-ion-transfer-across-the-blood-brain-and-blood-cerebrospinal-fluid-barriers-a-comparative-account-of-mechanisms-and-roles
#19
REVIEW
Stephen B Hladky, Margery A Barrand
The two major interfaces separating brain and blood have different primary roles. The choroid plexuses secrete cerebrospinal fluid into the ventricles, accounting for most net fluid entry to the brain. Aquaporin, AQP1, allows water transfer across the apical surface of the choroid epithelium; another protein, perhaps GLUT1, is important on the basolateral surface. Fluid secretion is driven by apical Na(+)-pumps. K(+) secretion occurs via net paracellular influx through relatively leaky tight junctions partially offset by transcellular efflux...
October 31, 2016: Fluids and Barriers of the CNS
https://www.readbyqxmd.com/read/27605583/the-gomez-equations-and-renal-hemodynamic-function-in-kidney-disease-research
#20
Petter Bjornstad, Marko Škrtić, Yuliya Lytvyn, David M Maahs, Richard J Johnson, David Z I Cherney
Diabetic kidney disease (DKD) remains the leading cause of end-stage renal disease. A major challenge in preventing DKD is the difficulty in identifying high-risk patients at an early, pre-clinical stage. Albuminuria and eGFR as measures of renal function in DKD research and clinical practice are limited by regression of one-third of patients with microalbuminuria to normoalbuminuria and eGFR is biased and imprecise in the normal-elevated range. Moreover, existing methods that are used to assess renal function do not give detailed insight into the location of the renal hemodynamic effects of pharmacological agents at the segmental level...
September 7, 2016: American Journal of Physiology. Renal Physiology
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