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Osmolarity tonicity

Sujuan Xu, Shizheng Huang, Zhilin Luan, Tingyue Chen, Yuanyi Wei, Miaomiao Xing, Yaqing Li, Chunxiu Du, Bing Wang, Feng Zheng, Nanping Wang, Youfei Guan, Jan-Åke Gustafsson, Xiaoyan Zhang
Hypertonicity in renal medulla is critical for the kidney to produce concentrated urine. Renal medullary cells have to survive high medullary osmolarity during antidiuresis. Previous study reported that farnesoid X receptor (FXR), a nuclear receptor transcription factor activated by endogenous bile acids, increases urine concentrating ability by up-regulating aquaporin 2 expression in medullary collecting duct cells (MCDs). However, whether FXR is also involved in the maintenance of cell survival of MCDs under dehydration condition and hypertonic stress remains largely unknown...
May 8, 2018: Proceedings of the National Academy of Sciences of the United States of America
Lauren K Goodhead, Frances M MacMillan
Since the discovery of the composition and structure of the mammalian cell membrane, biologists have had a clearer understanding of how substances enter and exit the cell's interior. The selectively permeable nature of the cell membrane allows the movement of some solutes and prevents the movement of others. This has important consequences for cell volume and the integrity of the cell and, as a result, is of utmost clinical importance, for example in the administration of isotonic intravenous infusions. The concepts of osmolarity and tonicity are often confused by students as impermeant isosmotic solutes such as NaCl are also isotonic; however, isosmotic solutes such as urea are actually hypotonic due to the permeant nature of the membrane...
June 1, 2017: Advances in Physiology Education
Marc Lim, Andrew Dibble
The intrinsic osmolality of aqueous solutions of sodium salt antisense oligonucleotides (ASOs) has been studied to inform formulation practices, understand the molecular basis underlying the difference between theoretical and empirical results, and determine suitable measurement methods. It was found that regardless of nucleotide sequence, ASO concentration of ∼140mg/mL has isotonic osmolality of ∼290mOsm/kg water (SI unit: mmol osmotically-active particles/kg water), such that lower concentration formulations require excipients for tonicity adjustment...
December 30, 2016: International Journal of Pharmaceutics
Christos Argyropoulos, Helbert Rondon-Berrios, Dominic S Raj, Deepak Malhotra, Emmanuel I Agaba, Mark Rohrscheib, Zeid Khitan, Glen H Murata, Joseph I Shapiro, Antonios H Tzamaloukas
Disturbances in tonicity (effective osmolarity) are the major clinical disorders affecting cell volume. Cell shrinking secondary to hypertonicity causes severe clinical manifestations and even death. Quantitative management of hypertonic disorders is based on formulas computing the volume of hypotonic fluids required to correct a given level of hypertonicity. These formulas have limitations. The major limitation of the predictive formulas is that they represent closed system calculations and have been tested in anuric animals...
May 2, 2016: Curēus
Mehdi Rasouli
The terms osmotic pressure, osmotic coefficient, osmole, osmolarity, osmolality, effective osmolality and delta osmolality are formally defined. Osmole is unit of the amount of substance, one mole of nonionized impermeant solute is one osmole. Assuming an ideal solution, osmotic pressure (π) in mmHg is 19.3 times the osmolarity. Osmolarity is defined as the number of milliosmoles of the solutes per liter of solution. Suitable equations are presented for the rapid calculation of the osmolarity of different solutions...
August 2016: Clinical Biochemistry
Xin Zhao, Xiaojuan Yan, Yuanhu Liu, Ping Zhang, Xin Ni
Osmoreception is essential for systemic osmoregulation, a process to stabilize the tonicity and volume of the extracellular fluid through regulating the ingestive behaviour, sympathetic outflow and renal function. The sensation of osmotic changes by osmoreceptor neurons is mediated by ion channels that detect the change of osmolarity in extracellular fluid. However, the molecular identity of these channels remains mysterious. AtCSC1and OSCA1,two closely related paralogues from Arabidopsis, have been demonstrated to form hyperosmolarity activated ion channels, which makes their mammalian orthologues-the members of TMEM63 proteins, possible candidates for osmoreceptor transduction channel...
June 2016: Cell Biochemistry and Function
Sarah Libert, François Willermain, Célia Weber, Angélic Bryla, Dany Salik, Françoise Gregoire, Nargis Bolaky, Laure Caspers, Jason Perret, Christine Delporte
PURPOSE: Macular edema, a frequently encountered complication of diabetic retinopathy (DR), results from alterations of the blood retinal barrier (BRB) and leads to modifications of the retinal pigmented epithelium (RPE) functions. Osmolar changes of the surrounding medium could be responsible for modifications of the RPE functions leading to disturbance of retinal homeostasis. The expression, activation and function of the key hyperosmolar response factor Tonicity Enhancer Binding Protein (TonEBP also called nuclear factor of activated T-cell 5 - NFTA5) was investigated in ARPE-19 cells, derived from human RPE, in response to hyperosmolar stimulation...
2016: Molecular Vision
Rosalinda Madonna, Gaia Giovannelli, Pamela Confalone, Francesca Vera Renna, Yong-Jian Geng, Raffaele De Caterina
BACKGROUND: We tested the hypothesis that glucose-induced hyperosmolarity, occurring in diabetic hyperglycemia, promotes retinal angiogenesis, and that interference with osmolarity signaling ameliorates excessive angiogenesis and retinopathy in vitro and in vivo. METHODS AND RESULTS: We incubated human aortic (HAECs) and dermal microvascular endothelial cells (HMVECs) with glucose or mannitol for 24 h and tested them for protein levels and in vitro angiogenesis...
January 29, 2016: Cardiovascular Diabetology
Harald Seeger, Daniel Kitterer, Joerg Latus, Mark Dominik Alscher, Niko Braun, Stephan Segerer
A rise in osmotic concentration (osmolarity) activates the transcription factor Nuclear Factor of Activated T Cells 5 (NFAT5, also known as Tonicity-responsive Enhancer Binding Protein, TonEBP). This is part of a regulatory mechanism of cells adjusting to environments of high osmolarity. Under physiological conditions these are particularly important in the kidney. Activation of NFAT5 results in the modulation of various genes including some which promote inflammation. The osmolarity increases in patients with renal failure...
2015: BioMed Research International
Ian Henry Lambert, Maria Stine Enghoff, Marie-Luise Brandi, Else Kay Hoffmann
The aim of this project was to analyze the regulation of p53 expression in NIH3T3 fibroblasts under the influence of increasing hyperosmotic stress. Expression of p53 showed a biphasic response pattern in NIH3T3 cells under increasing osmotic stress (337 mOsm to 737 mOsm) with a maximum at 587 mOsm. Under isotonic conditions p53 expression increased after addition of the proteasome inhibitor MG132 indicating that cellular p53 levels in unperturbed cells is kept low by proteasomal degradation. However, under hypertonic conditions p53 synthesis as well as p53 degradation were significantly reduced and it is demonstrated that the increase in p53 expression observed when tonicity is increased from 337 to 587 mOsm reflects that degradation is more inhibited than synthesis, whereas the decrease in p53 expression at higher tonicities reflects that synthesis is more inhibited than degradation...
June 2015: Physiological Reports
Mark Rohrscheib, Helbert Rondon-Berrios, Christos Argyropoulos, Robert H Glew, Glen H Murata, Antonios H Tzamaloukas
Although disturbances of serum tonicity (effective osmolality) may have dire consequences, only surrogate indices of tonicity are available in practice. This report identifies the appropriate index for expressing clinical states of dystonicity. Serum sodium concentration ([Na]S) and osmolality ([Osm]S) may be incongruent. When the tonicity state shown by [Osm]S is higher than [Na]S and the difference between the 2 indices is caused by an excess of solute that distributes in total body water, tonicity is described by [Na]S...
June 2015: American Journal of the Medical Sciences
Seung Ah Cha, Byung Mun Park, Yu Jin Jung, Soo Mi Kim, Kyung Pyo Kang, Won Kim, Suhn Hee Kim
To understand the pathophysiology of ischemia/reperfusion (I/R) - induced acute kidney injury (AKI), the present study defined changes in renal function, plasma renotropic hormones and its receptors in the kidney 2, 5, or 7 days after 45 min-renal ischemia in rats. Blood urea nitrogen, plasma creatinine, and osmolarity increased 2 days after I/R injury and tended to return to control level 7 days after I/R injury. Decreased renal function tended to return to control level 5 days after I/R injury. However, plasma concentrations of atrial natriuretic peptide and renin did not change...
July 2015: Peptides
G T Lee, M D Price, C A Mejia, H L Galan, J A Arroyo
OBJECTIVES: To assess the concentrations of inositol and sorbitol, and determine the expression of related osmolyte factors [nuclear factor of activated T cells 5, also known as tonicity responsive binding protein (NFAT5/TonEBP); sodium myo-inositol transporter (SLC5A3); and aldose reductase] in placentas of pre-eclamptic (PE) patients and trophoblast BeWo cells subjected to hypertonic stress in vitro. STUDY DESIGN: Control and PE placentas were collected. BeWo cells were cultured and subjected to a hyperosmolar solution for 4h...
December 2014: European Journal of Obstetrics, Gynecology, and Reproductive Biology
Zariel I Johnson, Irving M Shapiro, Makarand V Risbud
Degeneration of the intervertebral disc is characterized by changes in proteoglycan status, loss of bound water molecules, decreased tissue osmotic pressure and a resulting mechanical failure of the disc. A similar spectrum of changes is evident in osteoarthritic articular cartilage. When healthy, resident cells in these skeletal tissues respond to applied mechanical loads by regulating their own osmotic state and the hydration of the extracellular matrix. The transcription factor Tonicity-Responsive Enhancer Binding Protein (TonEBP or NFAT5) is known to mediate the osmoadaptive response in these and other tissues...
November 2014: Matrix Biology: Journal of the International Society for Matrix Biology
Jan Sobczyński, Gro Smistad, Anne Bee Hegge, Solveig Kristensen
The influence of four Pluronics block copolymers (i.e. F68, P123, F127, and L44) on the aggregation and solubilization of five structurally related meso-tetraphenyl porphyrin photosensitizers (PS) as model compounds for use in Photodynamic Therapy of cancer (PDT) was evaluated. Interactions between the PSs and Pluronics were studied at micromolar concentration by means of UV-Vis absorption spectrometry and by kinematic viscosity (υ) and osmolarity measurements at millimolar concentrations. Pluronic micelles were characterized by size and zeta potential (ζ) measurements...
2015: Drug Development and Industrial Pharmacy
Jennifer M Reinhart, Misty R Yancey, Lisa M Pohlman, Thomas Schermerhorn
Spurious increase in erythrocyte mean corpuscular volume (MCV) on automated cell analyzers is a well-characterized lab error in hypertonic patients. A difference between automated and manual MCV (dMCV) greater than 2 fl has been shown to predict hypertonicity in humans. The purpose of this study was to investigate dMCV as a marker for serum hypertonicity in dogs and to examine the relationship between dMCV and three methods of estimating serum tonicity: measured (OsMM), calculated (OsMC), and calculated effective (OsMCE) osmolalities...
June 2014: Research in Veterinary Science
C Bonvehi, M Ardiaca, S Barrera, M Cuesta, A Montesinos
Prevalence of hyponatraemia has not been extensively studied in pet rabbits, and the reference data for calculated plasma tonicity and osmolarity are not available. This retrospective clinical study reports the prevalence of hyponatraemia, hyposmolarity and hypotonicity in ill pet rabbits (n=356). The relationship between sodium and glucose levels was studied (n=134). Mortality rates within seven days associated with different sodium levels were calculated in ill rabbits (n=322). Venous blood samples in lithium heparin were processed using iStat EC8+ cartridges...
May 31, 2014: Veterinary Record
Michael I Lindinger, Matthew J Leung, Thomas J Hawke
Mouse and rat skeletal muscles are capable of a regulatory volume increase (RVI) after they shrink (volume loss resultant from exposure to solutions of increased osmolarity) and that this RVI occurs mainly by a Na-K-Cl-Cotransporter (NKCC)-dependent mechanism. With high-intensity exercise, increased extracellular osmolarity is accompanied by large increases in extracellular [lactate⁻]. We hypothesized that large increases in [lactate⁻] and osmolarity augment the NKCC-dependent RVI response observed with a NaCl (or sucrose)-induced increase in osmolarity alone; a response that is dependent on lactate⁻ influx through monocarboxylate transporters (MCTs)...
2013: PloS One
Jeroen C H Leijten, Steffan D Bos, Ellie B M Landman, Nicole Georgi, Holger Jahr, Ingrid Meulenbelt, Janine N Post, Clemens A van Blitterswijk, Marcel Karperien
INTRODUCTION: Osteoarthritis is, at least in a subset of patients, associated with hypertrophic differentiation of articular chondrocytes. Recently, we identified the bone morphogenetic protein (BMP) and wingless-type MMTV integration site (WNT) signaling antagonists Gremlin 1 (GREM1), frizzled-related protein (FRZB) and dickkopf 1 homolog (Xenopus laevis) (DKK1) as articular cartilage's natural brakes of hypertrophic differentiation. In this study, we investigated whether factors implicated in osteoarthritis or regulation of chondrocyte hypertrophy influence GREM1, FRZB and DKK1 expression levels...
2013: Arthritis Research & Therapy
J A Donlon, A Rothstein
The steady state passive efflux of salt from human red blood cells was measured in various low ionic strength media in which the osmotic pressure ranged from 200 to 600 milliosmolar. Sucrose was used as the nonpenetrating nonelectrolyte. If the flux is plotted against the log of the salt concentration, the data for each tonicity can be fitted by three straight-line segments separated by two sharp inflections, one at low external salt concentrations (0.1 to 0.3mM), confirming observations of LaCelle and Rothstein, and a second at higher salt concentrations (20 to 50 mM)...
December 1969: Journal of Membrane Biology
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