3HOH-osmotic water fluxes and ultrastructure of an epithelial syncytium

1981 ◽  
Vol 61 (2) ◽  
pp. 107-114 ◽  
Author(s):  
D. A. Brodie ◽  
R. B. Podesta
Keyword(s):  
Water Fluxes ◽  
Osmotic Water

scholarly journals Tissue Sources and Blood Flow Limitations of Osmotic Water Transport Across the Peritoneum

1999 ◽  
Vol 10 (2) ◽  
pp. 347-353
Author(s):  
HAILU DEMISSACHEW ◽  
JOANNE LOFTHOUSE ◽  
MICHAEL F. FLESSNER
Keyword(s):  
Blood Flow ◽  
Water Transport ◽  
Water Flow ◽  
Water Flux ◽  
Hypertonic Solution ◽  
Water Fluxes ◽  
Volume Changes ◽  
Doppler Flowmetry ◽  
Chamber Volume ◽  
Osmotic Water

Abstract. Despite the daily use of hypertonic solutions to remove fluid from patients throughout the world who are undergoing peritoneal dialysis, the tissue sources of this water flow are unknown. To study this phenomenon in specific tissues, small plastic chambers were affixed to parietal and visceral surfaces of the peritoneum and were filled with either an isotonic or hypertonic solution. The volume changes over 60 to 90 min were determined and divided by the chamber area to yield the volume flux. The hypertonic solution produced a positive flux into the chamber of 0.6 to 1.1 μl/min per cm2 in all tissues tested. In contrast, the isotonic solution resulted in a net loss or an insignificant change in the chamber volume. Additional experiments tested the influence of blood flow on the hypertonic water flux during periods of control, reduced (50 to 80%), or postmortem (no) blood flow, as determined by laser Doppler flowmetry. With the exception of the liver, small but insignificant changes in the flux into the chamber were observed during the period of reduced flow; all water fluxes were markedly depressed during the postmortem period. It is concluded that both parietal and visceral tissues are sources of osmotically induced water flow into the cavity. Except for the liver, marked blood flow reductions have small but insignificant effects on osmotic water transport.

Asymmetry in osmotic response of frog gastric mucosa

1980 ◽  
Vol 238 (4) ◽  
pp. G298-G302
Author(s):  
L. Villegas
Keyword(s):  
Gastric Mucosa ◽  
Water Flux ◽  
Mucosal Surface ◽  
Ion Fluxes ◽  
Water Fluxes ◽  
Serosal Surface ◽  
Opposite Surface ◽  
Osmotic Water ◽  
Osmotic Response ◽  
Net Water Flux

The effects of hyperosmolality of the serosal and mucosal bathing solutions on the transmucosal net water and ion fluxes were studied in frog gastric mucosa. Addition of 100 mosM glucose to the solution at the serosal surface produces a reversed mucosal-to-serosal net water flux of 7.1 +/- 1.4 microliter . cm-2 . h-1. When added to the abolished spontaneous net water flux, this results in an increment in the net water flux of -17.8 +/- 1.4 microliter . cm-2 . h-1. Addition of the same amount of glucose to the solution at the mucosal surface produces an increment in the serosal-to-mucosal net water flux of 3.7 +/- 1.1 microliter . cm-2 . h-1 when the solution at the opposite surface was kept in 220 mosmol/kg H2O. Simultaneous increments of both solutions of 320 to 420 and 420 to 520 mosM changes the osmotic serosal-to-mucosal induced fluxes to 1.9 +/- 0.9 and 3.4 +/- 1.6 microliter . cm-2 . h-1, respectively. The initial spontaneous net water fluxes measured in 220, 320, and 420 mosM solutions were 11.3 +/- 0.9, 6.9 +/- 1.6, and -1.5 +/- 1.5 microliter . cm-2 . h-1. It is proposed that the osmotic water flux is asymmetric, independent of the solutions tonicities, and not significantly affected by the sweep of solutes at the mucosal surface.

Blood Composition and Osmoregulation in Ammocoete Larvae

1980 ◽  
Vol 37 (11) ◽  
pp. 1665-1679 ◽  
Author(s):  
Ron Morris
Keyword(s):  
Freshwater Species ◽  
Water Fluxes ◽  
Blood Composition ◽  
Uptake Mechanism ◽  
Water Turnover ◽  
Chloride Uptake ◽  
Osmotic Water ◽  
Lampetra Planeri ◽  
Osmoregulatory Mechanism ◽  
Transport Type

Ammocoetes of all species are typical stenohaline freshwater animals which are able to regulate their blood and tissue ions very efficiently although they live in a very dilute environment. They excrete osmotic water by a well-developed kidney, and water turnover is high. Nephron units are sequentially arranged and have similar differentiated segments to those of other freshwater vertebrates. Total ion loss is low so the kidney must conserve ions efficiently. Ion loss is compensated by an ion-uptake mechanism, probably located in the interplatelet area of the gills. Here, the cells contain a sodium carrier whose transport rate is regulated by internal and external sodium levels; also they have mechanisms for potassium and chloride uptake. Both the gills and kidney have ion transport type cells, but the skin does not. The gills are probably the main access route for water, ions, and lampricides. The freshwater mechanism of osmoregulation persists beyond metamorphosis and thereafter many lampreys become euryhaline, but ammocoetes are unable to osmoregulate in hypertonic solutions and show passive responses. The adults of anadromous species like Lampetra fluviatilis and Petromyzon marinus develop a marine osmoregulatory mechanism which is similar to that of marine teleosts, whilst freshwater species like the landlocked P. marinus of the Great Lakes and the dwarf brook lamprey, Lampetra planeri, show reduced capacities for osmoregulation in seawater.Key words: ammocoetes, lampreys, osmoregulation, blood composition, gills, ion fluxes, kidney, urine, water fluxes, ion compartments

Chloride and osmotic water permeabilities of isolated rabbit renal papillary surface epithelium

1989 ◽  
Vol 257 (2) ◽  
pp. F218-F224 ◽  
Author(s):  
R. K. Packer ◽  
J. M. Sands ◽  
M. A. Knepper
Keyword(s):  
Interstitial Fluid ◽  
Ussing Chamber ◽  
Surface Epithelium ◽  
Fluid Composition ◽  
Water Fluxes ◽  
Chloride Permeability ◽  
Osmotic Water ◽  
Solute Fluxes ◽  
Dilution Potential ◽  
Cl Permeability

The papillary surface epithelium (PSE) covers the mammalian renal papilla. It has been proposed that water or solute fluxes across the PSE might result in changes in urine or medullary interstitial fluid composition. To study osmotic water and chloride permeabilities, the PSE was dissected from underlying medullary tissue and mounted in a small Ussing chamber. Osmotic water permeability was low (14.2 +/- 3.0 microns/s) and was unaffected by 100 nM vasopressin added to the basolateral surface. In contrast, the PSE showed a substantial chloride permeability of 3.1 +/- 0.4 x 10(-5) cm/s that decreased reversibly to 2.2 +/- 0.3 x 10(-5) cm/s (P less than 0.01) with vasopressin. Vasopressin also reversibly increased the transepithelial resistance of the PSE from 87 +/- 9 to 106 +/- 13 omega.cm2 (P less than 0.02). Apical bumetanide (10(-6) M) had no significant effect on PSE chloride permeability. The apparent Na-Cl permeability ratio (0.75 +/- 0.01) calculated from dilution potential measurements was not affected significantly by vasopressin or apical bumetanide. We conclude that it is unlikely that physiologically significant osmotic water fluxes occur across the papillary surface epithelium. However, the NaCl permeability is sufficiently high that physiologically significant transepithelial NaCl fluxes could occur under conditions associated with reflux of urine backward from the papillary tip.

Emissions of porewater compounds and gases from the subaquatic sediment disposal site “rodewischhafen”, hamburg harbour

1998 ◽  
Vol 37 (6-7) ◽  
pp. 87-93 ◽  
Author(s):  
M. Kussmaul ◽  
A. Groengroeft ◽  
H. Koethe
Keyword(s):  
Water Surface ◽  
Disposal Site ◽  
Dredged Material ◽  
Water Fluxes ◽  
Gas Emissions ◽  
Fine Grained ◽  
Deposit Surface ◽  
Groundwater Samples ◽  
High Concentrations ◽  
Mud Deposit

In the year 1993 a confined and unused harbour basin was used to store 290,000 m3 of fine-grained dredged material from Hamburg harbour. About 70% of the deposit surface was water covered. The edge areas were above the water table and covered with reed. Emissions of dissolved compounds into the groundwater, as well as surface gas emissions were measured from 1994 to 1996. As indicators for water fluxes from the deposit we used NH4+ and HCO3− because of their high concentrations in mud porewater in comparison to groundwater. The average concentrations of NH4+ and HCO3− in the porewater increased during 2 years from 85 to 250 mg NH4+ 1−1 and from 2.0 to 3.1 g HCO3− 1−1, while the groundwater samples showed constant values of 8 mg NH4+ 1−1 and 0.7 g HCO3− 1−1. Furthermore, the average gas emissions over the water surface were 3.2 g CH4 m−2 d−1 and 0.8 g CO2 m−2 d−1. In contrast, no methane and 3.0 g CO2 m−2 d−1 were emitted from land areas. The results indicated, that there were no significant emissions of mud porewater compounds into the groundwater but high CH4-emissions over the water covered surface of the mud deposit.

scholarly journals Comparison of blue and green water fluxes for different land use classes in a semi-arid cultivated catchment using remote sensing

2021 ◽  
Vol 36 ◽  
pp. 100860
Author(s):  
Anna Msigwa ◽  
Hans C. Komakech ◽  
Elga Salvadore ◽  
Solomon Seyoum ◽  
Marloes L. Mul ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Green Water ◽  
Water Fluxes ◽  
Semi Arid

scholarly journals Photochemically induced cyclic morphological dynamics via degradation of autonomously produced, self-assembled polymer vesicles

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Chenyu Lin ◽  
Sai Krishna Katla ◽  
Juan Pérez-Mercader
Keyword(s):  
Morphological Evolution ◽  
Chemical Degradation ◽  
Chemical Mechanism ◽  
Giant Vesicles ◽  
Water Influx ◽  
Physico Chemical ◽  
Osmotic Water ◽  
Periodic Growth ◽  
Oxygen Conditions ◽  
Self Assembled

AbstractAutonomous and out-of-equilibrium vesicles synthesised from small molecules in a homogeneous aqueous medium are an emerging class of dynamically self-assembled systems with considerable potential for engineering natural life mimics. Here we report on the physico-chemical mechanism behind a dynamic morphological evolution process through which self-assembled polymeric structures autonomously booted from a homogeneous mixture, evolve from micelles to giant vesicles accompanied by periodic growth and implosion cycles when exposed to oxygen under light irradiation. The system however formed nano-objects or gelation under poor oxygen conditions or when heated. We determined the cause to be photoinduced chemical degradation within hydrated polymer cores inducing osmotic water influx and the subsequent morphological dynamics. The process also led to an increase in the population of polymeric objects through system self-replication. This study offers a new path toward the design of chemically self-assembled systems and their potential application in autonomous material artificial simulation of living systems.

scholarly journals Pseudo-streaming potentials in Necturus gallbladder epithelium. II. The mechanism is a junctional diffusion potential.

1992 ◽  
Vol 99 (3) ◽  
pp. 317-338 ◽  
Author(s):  
L Reuss ◽  
B Simon ◽  
C U Cotton
Keyword(s):  
Time Course ◽  
Bathing Solution ◽  
Intercellular Spaces ◽  
Similar Time ◽  
Streaming Potentials ◽  
Osmotic Water ◽  
Lateral Intercellular Spaces ◽  
Transepithelial Voltage ◽  
Time Courses ◽  
Good Agreement

The mechanisms of apparent streaming potentials elicited across Necturus gallbladder epithelium by addition or removal of sucrose from the apical bathing solution were studied by assessing the time courses of: (a) the change in transepithelial voltage (Vms). (b) the change in osmolality at the cell surface (estimated with a tetrabutylammonium [TBA+]-selective microelectrode, using TBA+ as a tracer for sucrose), and (c) the change in cell impermeant solute concentration ([TMA+]i, measured with an intracellular double-barrel TMA(+)-selective microelectrode after loading the cells with TMA+ by transient permeabilization with nystatin). For both sucrose addition and removal, the time courses of Vms were the same as the time courses of the voltage signals produced by [TMA+]i, while the time courses of the voltage signals produced by [TBA+]o were much faster. These results suggest that the apparent streaming potentials are caused by changes of [NaCl] in the lateral intercellular spaces, whose time course reflects the changes in cell water volume (and osmolality) elicited by the alterations in apical solution osmolality. Changes in cell osmolality are slow relative to those of the apical solution osmolality, whereas lateral space osmolality follows cell osmolality rapidly, due to the large surface area of lateral membranes and the small volume of the spaces. Analysis of a simple mathematical model of the epithelium yields an apical membrane Lp in good agreement with previous measurements and suggests that elevations of the apical solution osmolality elicit rapid reductions in junctional ionic selectivity, also in good agreement with experimental determinations. Elevations in apical solution [NaCl] cause biphasic transepithelial voltage changes: a rapid negative Vms change of similar time course to that of a Na+/TBA+ bi-ionic potential and a slow positive Vms change of similar time course to that of the sucrose-induced apparent streaming potential. We conclude that the Vms changes elicited by addition of impermeant solute to the apical bathing solution are pseudo-streaming potentials, i.e., junctional diffusion potentials caused by salt concentration changes in the lateral intercellular spaces secondary to osmotic water flow from the cells to the apical bathing solution and from the lateral intercellular spaces to the cells. Our results do not support the notion of junctional solute-solvent coupling during transepithelial osmotic water flow.

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