OBJECTIVE Osmotic gradient-induced volume change and sarcolemmal water permeability of cardiac myocytes were evaluated to characterize the mechanism of water flux across the plasma membranes. METHODS Cell surface dimensions were measured from isolated guinea-pig and rat ventricular myocytes by digital videomicroscopy, and membrane hydraulic conductivity (L(p)) was obtained by analyzing the ti...

Normal nervous system function is critically dependent on the balance of water and ions in the extracellular space (ECS). Pathological reduction in brain interstitial osmolarity results in osmotically-driven flux of water into cells, causing cellular edema which reduces the ECS and increases neuronal excitability and risk of seizures. Astrocytes are widely considered to be particularly suscepti...

Corneal thickness changes were measured on human subjects who wore gel lenses that varied in center thickness. Using these measurements and the results of an earlier study in which changes in corneal thickness were monitored on human corneas exposed to oxygen tensions below that in air, we showed that the oxygen tension under most contact lenses varies from 0 to 25 mm Hg which produces a corres...

Maintenance of corneal hydration is dependent on the active transport properties of the corneal endothelium. We tested the hypothesis that lactic acid efflux, facilitated by buffering, is a component of the endothelial fluid pump. Rabbit corneas were perfused with bicarbonate-rich (BR) or bicarbonate-free (BF) Ringer of varying buffering power, while corneal thickness was measured. Perfusate wa...

The role of swelling-activated currents in cell volume regulation is unclear. Currents elicited by swelling rabbit ventricular myocytes in solutions with 0.6-0.9x normal osmolarity were studied using amphotericin perforated patch clamp techniques, and cell volume was examined concurrently by digital video microscopy. Graded swelling caused graded activation of an inwardly rectifying, time-indep...

This study examined the mechanism of swelling for high acyl (HA) gellan gum and impacts on hydrogel mechanical properties release a model drug (glucose). Controlling material entrapped drugs during use in aqueous environments, such as stomach or bodily fluids, are crucial designing functional applications. Swelling HA was controlled by varying osmotic environment with salts solvents, effects ge...

Following treatment with ultraviolet radiation, human red cells leak cations at accelerated rates which depend on the radiation dose. With one exception (initial Na efflux), these accelerated cation fluxes fit the Ussing flux-ratio criterion for passive diffusion. Na efflux is transiently high, but with time falls to the value expected on the basis of the other cation fluxes. An equation based ...

Articular cartilage exhibits complex mechano-electrochemical behaviour due to its anisotropy, inhomogeneity and material non-linearity. In this work, the thickness and radial dependence of cartilage properties are incorporated into a 3D mechano-electrochemical model to explore the relevance of heterogeneity in the behaviour of the tissue. The model considers four essential phenomena: (i) osmoti...

Neurons and glia experience rapid fluctuations in transmembrane solute and water fluxes during normal brain activity. Cell volume must be regulated under these conditions to maintain optimal neural function. Almost nothing is known, however, about how brain cells respond to volume challenges induced by changes in transmembrane solute flux. As such, we characterized the volume-regulatory mechani...

Damage induced in low-k porous organosilicate glass SiCOH dielectric films by exposure to an electron cyclotron resonance ECR plasma was investigated. The effects of charged-particle bombardment and vacuum ultraviolet radiation were separated. Flux measurements showed that the ECR plasma has a greater photon flux in the vacuum ultraviolet VUV range than in the UV range. Damage was measured by e...