SEARCH · Search PubMed

Results for “OSMOSIS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources

PubMed1986

Effects of diabetes and insulin treatment on sorbitol and water of rat lenses.

Since increased lens sorbitol and osmotic swelling are central causative features of cataract in diabetic rats, the effects of insulin treatment on lens sorbitol, water, sodium, and potassium were studied. The sorbitol concentration in early stage diabetic lenses was greater than in normal ones by 83 mmol/kg water, and the lens water was greater by 1.3%. Sodium was greater by 9 mmol/kg water; potassium was less by the same amount so that the sum of sodium and potassium was not different. In insulin-treated diabetic lenses, the sorbitol was less than in untreated diabetic lenses by 39 mmol/kg water, and the lens water was not different. Insulin restored the potassium, but not the sodium, to normal concentration so that the sum of sodium and potassium was greater by 16 mmol/kg water. The differences in lens water were less than would be expected on the basis of osmosis due to differences in sorbitol and suggested that the lenses were able to maintain their water content within a narrow range by losing or gaining solutes to offset the differences in sorbitol.

Alloxan↗

PubMed1977

[Pyrogen-free sterile water for operative endoscopy (author's transl)].

In transurethral endoscopic operations we have maximal demands for the water conditions where, as in urology, for the diagnostic endoscopy one mostly uses sterile filtered but on principle hydrant water containing pyrogen. First the determinations of the order for drinking water and its possible consequences for irrigator systems are laid down. Water for injections like the irrigator water in operative endoscopy must conform to the demands in pharmacopoeia of the different countries. With the new combination of reverse osmosis system with an irrigator, hydrant water can be purified to pyrogen-free sterile water in the place of treatment.

Female↗

PubMed2000

Dialysis membranes for blood purification.

All of the artificial membranes in industrial use, such as a reverse-osmosis membrane, dialysis membrane, ultrafiltration membrane, microfiltration membrane and gas separation membrane, also have therapeutic applications. The most commonly used artificial organ is the artificial kidney, a machine that performs treatment known as hemodialysis. This process cleanses the body of a patient with renal failure by dialysis and filtration, simple physicochemical processes. Hemodialysis membranes are used to remove accumulated uremic toxins, excess ions and water from the patient via the dialysate, and to supply (deficit) insufficient ions from the dialysate. Dialysis membranes used clinically in the treatment of patients with renal failure account for by far the largest volume of membranes used worldwide; more than 70 million square meters are used a year. Almost all dialyzers now in use are of the hollow-fiber type. A hollow-fiber dialyzer contains a bundle of approximately 10000 hollow fibers, each with an inner diameter of about 200 microm when wet. The membrane thickness is about 20-45 microm, and the length is 160-250 mm. The walls of the hollow fibers function as the dialysis membrane. Various materials, including cellulose-based materials and synthetic polymers, are used for dialysis membranes. This paper reviews blood purification, hemodialysis and dialysis membranes.

Biocompatible Materials↗

PubMed2000

Differentiation of ion-associated and osmotically driven water transport in canine airways.

We hypothesized that water transport associated with fluxes of Na(+) and Cl(-) across airway epithelium coexists and is distinct from osmotically driven water transport. To investigate this, we anesthetized and mechanically ventilated dogs (n = 8) with warm humid air. The trachea of each dog was sequentially challenged with 250-mOsm and 950-mOsm mannitol aerosols given 30 min apart. Respiratory tract fluid output (RTFO) was collected at the posterior commissure at 6-min intervals. The percentages of mannitol in the RTFO were determined with fluorescent tracers and were subtracted from the RTFO to give airway secretory output (ASO). Unbound [Na(+)] and [Cl(-)] in the RTFO were measured. Following the 250-mOsm mannitol challenge, the ASO as well as its Na(+) and Cl(-) contents increased. Following the 950-mOsm challenge, there was a further increase in ASO without any further increases in Na(+) and Cl(-) contents. Increased mucociliary transport accounted for only part of the increase in ASO. These data are consistent with the hypothesis that net water transport into the airway lumen is the vectorial sum of the water fluxes associated with actively driven intracellular Na(+) and Cl(-) transport and the water flux due to osmosis.

Aerosols↗

PubMed2005

Electric field-assisted deposition of nanowires on carbon nanotubes for nanoelectronics and sensor applications.

Manipulation and control of matter at the nanoscale and atomic scale levels are crucial for the success of nanoscale sensors and actuators. The ability to control and synthesize multilayer structures using carbon nanotubes that will enable the building of electronic devices within a nanotube is still in its infancy. In this paper, we present results on selective electric field-assisted deposition of metals on carbon nanotubes realizing metallic nanowire structures. Silver and platinum nanowires have been fabricated using this approach for their applications in chemical sensing as catalytic materials to sniff toxic agents and in the area of biomedical nanotechnology for construction of artificial muscles. Electric field-assisted deposition allows the deposition of metals with a high degree of selectivity on carbon nanotubes by manipulating the charges on the surface of the nanotubes and forming electrostatic double-layer supercapacitors. Deposition of metals primarily occurred due to electrochemical reduction, electrophoresis, and electro-osmosis inside the walls of the nanotube. SEM and TEM investigations revealed silver and platinum nanowires between 10 nm and 100 nm in diameter. The present technique is versatile and enables the fabrication of a host of different types of metallic and semiconducting nanowires using carbon nanotube templates for nanoelectronics and a myriad of sensor applications.

Biosensing Techniques↗

PubMed1984

Radiography of healing dialysis osteodystrophy.

Characteristic skeletal changes of dialysis bone disease associated with multiple fractures were found in ten patients on prolonged regular (high aluminium) haemodialysis. A subsequent prospective investigation with serial radiography demonstrated healing approximately twelve months after a changed treatment regime. The treatment used was deionized or reverse osmosis water dialysis and renal transplantation. The typical osteomalacic and osteosclerotic changes and particularly metaphyseal sclerosis were found to be associated with more rapid clinical healing, whereas secondary hyperparathyroidism indicated delayed healing. It is suggested that plasma aluminium imbalance may lead to disturbance of bone formation with fractures, while healing is associated with normal serum aluminium levels and is manifested radiologically by osteosclerosis, particularly in the metaphyses.

Adult↗

PubMed1991

Processes for water reclamation.

Water treatments fall into two broad classes; those that remove or destroy specific classes of pollutants, i.e. color, metal ions, hardness, sediment, bacteria, etc., and those that remove water from nearly all of the pollutants. The first class includes sedimentation, biological treatment by microbes, chemical precipitation, adsorption on active carbon or ion exchange resins, and disinfection. The second class includes distillation, freezing and reverse osmosis (RO). The first class are the least expensive in terms of energy and have a long history of successful use on a large scale to reclaim water containing sewage. Most of the second group are energy intensive and have been used primarily on a moderate scale. All processes, except disinfection, leave a residual sludge or brine that contains a substantial quantity of water. Many of the problems of treating waste water for reuse on Earth stem from the fact that waste water carries pathogenic organisms from one location to another and may spread disease over long distances. In a closed group, such as in a Space Station, there are so many other routes for transfer of microorganisms, i.e. in the air, on surfaces, by hand-to-mouth, that undue emphasis on disinfection of water is inappropriate. Successful examples of water reuse on Earth are reviewed in terms of their possible application in space.

Carbon↗

PubMed1997

Membrane attack induced by HlyA, a pore-forming toxin of Vibrio cholerae.

Determining the activity of purified toxins has generally provided the basis for establishing their role in the host-pathogen relationship. The bacterial genus Vibrio produces a number of exotoxins in addition to cholera toxin, including haemolysin A (HlyA; Vibrio cholerae) and thermostable direct haemolysin (TDH; Vibrio parahaemolyticus), both of which possess membrane-targeting cytolytic activity. The action of HlyA has been analyzed using protocols previously applied to TDH: lysis and flux experiments on human erythrocytes showed that HlyA similarly causes lysis after cell swelling (by colloid osmosis) due to an elevation of cation permeability. However, kinetic measurements of flux, haemolysis and cation selectivity showed that HlyA and TDH form pores with distinct and characteristic features.

Adult↗

PubMed2003

Amino acids modulate ion transport and fluid secretion by insect Malpighian tubules.

Insect haemolymph typically contains very high levels of free amino acids. This study shows that amino acids can modulate the secretion of ions and water by isolated Malpighian tubules of Rhodnius prolixus and Drosophila melanogaster. Secretion rates of Rhodnius tubules in amino-acid-free saline increase after addition of serotonin to a peak value, then slowly decline to a plateau. Addition of glutamine, glutamate or aspartate to such tubules increases secretion rates dramatically relative to the controls in amino-acid-free saline, and these increases are sustained for 1-2 h. Seven other amino acids have more modest stimulatory effects, whereas lysine and arginine are inhibitory. Secreted fluid pH and Na(+) concentration increase and K(+) concentration decreases in response to glutamine. Pre-incubation of unstimulated tubules in saline solutions containing amino acids followed by stimulation with serotonin in amino-acid-free saline shows that the effects of amino acids far outlast the duration of exposure to them. Amino acids do not appear to be important as metabolites in Rhodnius tubules, nor do they act to draw significant amounts of water into the lumen by osmosis. Significant stimulation of fluid secretion can be achieved by physiological levels of particular amino acids, whereas those amino acids that inhibit fluid secretion only do so at concentrations much above those at which they occur naturally in the haemolymph. Secretion rates of unstimulated or stimulated Drosophila tubules are increased by pre-incubation in saline solutions containing glutamine or methionine or by continuous exposure to glutamine, methionine or tyrosine. Cysteine dramatically inhibited fluid secretion by Drosophila tubules, but only at concentrations well above the physiological range. We suggest that the amino acids probably function as compatible intracellular osmolytes that are necessary for sustained secretion at high rates by the Malpighian tubules.

Amino Acids↗

PubMed2005

Plasma aluminium: a redundant test for patients on dialysis?

BACKGROUND: Aluminium toxicity as a cause of dementia, osteodystrophy and anaemia in patients receiving renal dialysis was first described in the 1970s and led to the regular monitoring of aluminium in plasma and dialysate water. However, aluminium phosphate binders have now been replaced by calcium-based binders or sevelamer and reverse osmosis (RO) water is used in the preparation of dialysate fluid. This has reduced the exposure of dialysis patients to aluminium and it is therefore opportune to review aluminium monitoring in patients undergoing regular renal dialysis. METHODS: Plasma and water aluminium results were audited over the period January 2000-January 2004, with results obtained from nine renal dialysis units in the UK. Patients with a plasma aluminium concentration in the toxic range (>3.7 micromol/L) were followed up by contacting the relevant consultant. RESULTS: Plasma aluminium results were collected on 1626 patients over the four-year period (mean=0.47 micromol/L, median=0.3 micromol/L, range 0.07-30.26 micromol/L, n=5918). Forty-six patients had an aluminium concentration >3.7 micromol/L and nine were not retested. Only three patients had a repeat aluminium concentration >2.2 micromol/L, one being a result of desferrioxamine treatment, with no further clinical information available on the other two. All renal units are using RO water to prepare dialysate and aluminium-based phosphate binders are no longer prescribed. Only one of 212 RO water aluminium concentrations measured was >10 microg/L. Patients with clinical symptoms of overt aluminium toxicity were not identified in this population. CONCLUSION: The role of aluminium monitoring in long-term renal dialysis patients needs re-evaluation. Regular monitoring of plasma aluminium may not be required, but should be considered in any patient showing signs or symptoms of aluminium toxicity or exposed to a contaminated water supply. It is more important that RO water supplies are maintained and monitored. Environmental aluminium as a source of sample contamination should be considered and eliminated during blood collection and sample processing.

Aluminum↗

PubMed1998

Genetic control of fission yeast cell wall synthesis: the genes involved in wall biogenesis and their interactions in Schizosaccharomyces pombe.

The fungal cell wall is an essential structure which protects cells from various environmental stresses such as hyper- or hypo-osmosis, and endows them with specific morphology in response to their life or cell division cycle. In addition, the cell wall has a variety of enzymatic activities per se, which are required for nutritional uptake, secretion, and cell adhesion including mating processes. In addition to these cytological interests, clinical demands to clarify the regulatory mechanisms of cell wall synthesis have been increasing, since the cell wall is a unique and effective target of antifungal agents. However, the molecular mechanisms are poorly understood at present, although the role of several signal transduction pathways have recently been implicated in regulation. In this review, the author focuses on genes and their interactions which are involved in fission yeast cell wall biogenesis.

Animals↗

PubMed2000

Saline solutions: the quest for fresh water.

Despite steady advances in the technology, desalination remains one of the most expensive ways to produce potable water. But as water scarcity forces communities to find new sources of drinking water, scientists are developing innovations that may soon make desalination a reasonable option for many more communities. The newest approach to desalination is membrane systems, which include reverse osmosis and electrodialysis systems. Current research seeks to make these systems more effective and less likely to produce environmentally hazardous by-products. Many facilities use traditional distillation to desalinate water, and efforts are being made to combine membranes and distillation for more efficient systems.

Fresh Water↗

PubMed1999

TCE treatment pasta-bilities.

Monsanto's "Lasagna" process uses layers of treatment zones spaced between buried electrodes to remove trichloroethylene (TCE) from contaminated soil and groundwater. TCE is used primarily as a metal degreaser as well as in products such as dyes, printing ink, and paint. TCE can eventually make its way into the environment and is prevalent in the water and soil of industrialized nations. Although TCE breaks down in a few days when released into the atmosphere, it degrades much more slowly in soil, taking months or years. Moreover, it is often broken down by microbes into toxic substances such as vinylidene chloride (a suspected human carcinogen) and vinyl chloride (a known human carcinogen). The Lasagna process is based on the principle of electro-osmosis, in which an electric current draws water from low--permeability soils such as clays, silts, and fine sands. To remove TCE from contaminated soils, Monsanto scientists added layers of filtering media, which attack the contaminant as it is pulled from electrode to electrode. The technology has been tested at the Paducah Gaseous Diffusion Plant in western Kentucky, where it removed over 98% of TCE from contaminated soil.

Humans↗

PubMed1994

Determination of the kinetics of Na+/H+ exchange in platelets using the Coulter S-plus cell counter.

Cell swelling, as measured by electronic cell sizing, is a good indicator of the Na+/H+ exchange activation. In this study the kinetic properties of the Na+/H+ exchanger were determined with the aid of the Coulter S-Plus VI D haematological cell counter. Cell swelling was measured in platelets suspended in Na-propionate medium. The rapid entry and intracellular dissociation of propionic acid induces activation of the exchanger, and in turn the uptake of water by osmosis. The fractional volume increase measured by the Coulter S-Plus was dependent on the external Na-concentration, with Km = 86 mmol/l. Saturation was reached at a propionate concentration of 140 mmol/l. Inhibition by amiloride was dose-dependent with Ki = 24 mumol/l. The activity of the exchanger was not modified by ouabain. These data are generally consistent with those published in previous reports, and indicate that automated haematological analysers are appropriate for the study of this aspect of platelet function.

Amiloride↗

PubMed2000

Biochemical and hematological changes in low-level aluminum intoxication.

The aim of this study was to investigate the biochemical and hematological changes in patients on routine hemodialysis treatment when they were accidentally exposed to moderately high serum aluminum concentrations during a period of time of less than four months. We studied the changes in biochemical and hematological measurements in 33 patients on dialysis in our hospital before and during the exposure to about 0.85 pmol/l of aluminum in dialysis water due to a malfunction of the reverse osmosis system of water purification. Patients showed a decrease in the hemoglobin concentration from 115+/-12.4 g/l to 108+/-12.2 g/l (p=0.026) and in the mean corpuscular hemoglobin concentration from 5.15+/-0.22 to 5.02+/-0.30 mmol/l (p=0.014). Ferritin was decreased from 243+/-192 microg/l to 196+/-163 microg/l (p=0.047) and transferrin saturation from 0.20+/-0.06 to 0.15+/-0.07 (p=0.004). Biochemical measurements related to calcium-phosphate metabolism did not change. Otherwise, all patients showed an increase in serum aluminum from 0.56+/-0.44 to 1.63+/-0.52 micromol/l (p<0.001). No differences were detected in serum aluminum between patients receiving and not receiving oral aluminum salts. Even moderately high aluminum concentrations maintained during a short period of time could produce significant hematological alterations and a depletion of body iron stores before clinical manifestations were evident.

Administration, Oral↗

PubMedDate not supplied

A multi-purpose system for water purification and sea-water softening.

A novel technique that can be used for reacting toxic carbon dioxide (CO2) emissions from power plants and other combustion wastes with sea water is described. A chemical interaction between CO2 and the cations in sea water, with the pH electrolytically regulated, can precipitate almost all the calcium and magnesium ions, as well as some sodium and potassium ions, as carbonates and bicarbonates. The carbonates and bicarbonates thus prepared can then be mixed with ash to yield a building material. Sulfur ions will be neutralized with calcium and magnesium, and the remaining ions can be removed using reverse osmosis or some other method. The technology and equipment for purification are based on modules that can be used for industrial waste-water, sea water, solutions, and otherwise. The module for separation of sand and suspended coarse substances consists of a tank for flocculation, coagulation, and precipitation of solid particles; and a low-pressure hydrocyclone. The module for purification from oil and fine suspensions is based on column flotation, flotation with a special ejector, and adhesion flotation. The module for ions and colloids consists of an absorbing filter with zeolite, fly ash, and other absorbing materials. Using a laboratory model consisting of a special mini-plant, we processed 10 L of factory-waste water containing more than 20 g/L organic content (compare with the upper limit of 0.02 g/L allowed by the Ministry of Environmental Protection in Israel). After the experimental solution was treated and evaporated to a small bulk, the water obtained was almost clear. On the basis of the results in the model, we present a scaled-up process for the design, development, and production of equipment for and the assembly of a large installation for drainage and water purification.

Seawater↗

PubMed2006

Transdermal iontophoresis.

Iontophoresis is a technique used to enhance the transdermal delivery of compounds through the skin via the application of a small electric current. By the process of electromigration and electro-osmosis, iontophoresis increases the permeation of charged and neutral compounds, and offers the option for programmed drug delivery. Interest in this field of research has led to the successful delivery of both low (lidocaine) and high molecular drugs, such as peptides (e.g., luteinising hormone releasing hormone, nafarelin and insulin). Combinations of iontophoresis with chemical enhancers, electroporation and sonophoresis have been tested in order to further increase transdermal drug permeation and decrease possible side effects. In addition, rapid progress in the fields of microelectronics, nanotechnology and miniaturisation of devices is leading the way to more sophisticated iontophoretic devices, allowing improved designs with better control of drug delivery. Recent successful designing of the fentanyl E-TRANS iontophoretic system have provided encouraging results. This review will discuss basic concepts, principles and applications of this delivery technique.

Administration, Cutaneous↗

PubMedDate not supplied

Photooxidative treatment of sulfurous water for its potabilization.

The feasibility of potabilization of sulfurous water was investigated by photochemical oxidation processes using a batch photoreactor and a continuous-flow photoreactor, equipped with UV lamps of 1000 W and 1500 W, respectively. Additionally, two advanced processes of oxidation were applied i.e. with a use of a UV light/H2O2/air and UV light/H2O2/O3/air. These two processes were compared for their efficiency to the direct oxidation process where ozone is used in the absence of UV light. Results obtained for both advanced processes showed better oxidation than takes place by ozone in the absence of UV light. After the photooxidation processes, different processes for the absorption or precipitation of sulfates were investigated to comply with the World Health Organization (WHO) norm that demands a limit of < or =250 mg L(-1) of SO4(2-) in drinking water. Additionally, reverse osmosis was simulated using Osmonics Inc. software to predict the feasibility of lowering the salt concentration below WHO limits.

Air↗