Effects of replacing medium sodium by choline, caesium, or rubidium, on water and ion contents of renal cortical slices

Removal of radioactive cesium from contaminated water by whey protein amyloids-carbon hybrid filters

We report on the application of an innovative whey protein amyloids–carbon hybrid filter for the removal and disposal of the long-lived radioactive fission product ¹³⁷Cs from aqueous samples. Test experiments revealed a reduction of ¹³⁷Cs radioactivity by a factor of 340 compared to the initial solution, with an efficiency as high as 99.7%. The adsorption capacity of the membrane was explored by performing several cycles of filtration, indicating a potential retention of more than 115 MBq per gram of filtering material at the applied experimental conditions. These results pave the way for further investigations on the applicability of this filter material to other nuclear fission products.

The efficient removal of the long-lived fission product ¹³⁷Cs from radioactive water by a filter material based on whey protein fibrils and activated carbon.

Sodium-23 and proton nuclear magnetic resonance imaging studies of carbon tetrachloride-induced liver damage in the rat

Magnetic resonance imaging techniques were used to investigate the response of the liver of the rat in situ to a toxicological challenge by carbon tetrachloride. Proton images were taken as transverse slices through the rat before and after intraperitoneal administration of the hepatotoxin. Two to three hours after carbon tetrachloride was given, a region of high proton signal intensity was observed where the portal vein enters the liver. Sodium-23 images were also taken, and a region of high sodium intensity was observed in the same location within the liver as the increased proton intensity. The results suggest that acute administration of carbon tetrachloride induces localized liver damage in the region where the hepatotoxin first enters the liver. This liver damage is manifest as edema with a buildup of sodium ion and water, which can be readily detected by sodium-23 and proton NMR imaging techniques, respectively.

Effects of axotomy on distribution and concentration of elements in rat sciatic nerve

X-ray microprobe analysis was used to determine the effects of axotomy on distribution and concentration (millimoles of element per kilogram dry weight) of Na, P, Cl, K, and Ca in frozen, unfixed sections of rat sciatic nerve. Elemental concentrations were measured in axoplasm, mitochondria, and myelin at 8, 16, and 48 h after transection in small-, medium-, and large-diameter fibers. In addition, elemental composition was determined in extraaxonal space (EAS) and Schwann cell cytoplasm. During the initial 16 h following transection, axoplasm of small fibers exhibited a decrease in dry weight concentrations of K and Cl, whereas Na and P increased compared to control values. Similar changes were observed in mitochondria of small axons, except for an early, large increase in Ca content. In contrast, intraaxonal compartments of larger fibers showed increased dry weight levels of K and P, with no changes in Na or Ca concentrations. Both Schwann cell cytoplasm and EAS at 8 and 16 h after injury had significant increases in Na, K, and Cl dry weight concentrations, whereas no changes, other than an increase in Ca, were observed in myelin. Regardless of fiber size, 48 h after transection, axoplasm and mitochondria displayed marked increases in Na, Cl, and Ca concentrations associated with decreased K. Also at 48 h, both Schwann cell cytoplasm and EAS had increased dry weight concentrations of Na, Cl, and K. The results of this study indicate that, in response to nerve transection, elemental content and distribution are altered according to a specific temporal pattern. This sequence of change, which occurs first in small axons, precedes the onset of Wallerian degeneration in transected nerves.

Sodium-hydrogen ion exchange in rabbit renal cortical slices incubated in acetate media

1. Thin slices (0.2-0.3 mm) of rabbit renal cortex have been incubated in isosmotic oxygenated acetate media at 25 degrees C with or without ouabain (10(-3) M), amiloride (2 x 10(-3) M) or iodoacetamide (10(-3) M). 2. Slices in normal isosmotic 146 mM-sodium-132 mM-acetate media swelled as reported previously (Cooke & Macknight, 1984). This swelling was not prevented by amiloride or by metabolic inhibition. 3. Slices in isosmotic 132 mM-choline-132 mM-acetate media gained much less water and were little affected by ouabain, amiloride or metabolic inhibition. Choline was able to substitute neither for sodium nor for potassium in activating preparations of renal cortical Na+-K+-ATPase in chloride or in acetate media. 4. Slices in isosmotic 20 mM-sodium-132 mM-acetate medium swelled nearly as much as did slices in normal sodium acetate medium. However, this swelling was impaired markedly by amiloride, by ouabain and by metabolic inhibition. 5. There was a direct correlation between medium sodium concentration and slice water content as sodium was increased from 1.25 to 30 mM in 132 mM-acetate media. However, up to a sodium concentration of 10 mM, amiloride (2 x 10(-3) M) completely prevented this increase in water content. 6. Increasing medium amiloride concentration from 10(-5) to 10(-3) M progressively inhibited cellular swelling in 10 mM-sodium-132 mM-acetate medium. It is concluded that, under these experimental conditions, the dominant pathway for hydrogen ion extrusion from the cells was via amiloride-sensitive sodium-hydrogen exchange. 7. The results are discussed in terms of a model which explains cellular swelling in acetate media in terms of (a) non-ionic diffusion of acetic acid across plasma membranes impermeable to the acetate anion, (b) removal from the cells of the hydrogen ion gained with the acetate by amiloride-sensitive sodium-hydrogen counter-transport and (c) subsequent extrusion of sodium from the cell accompanied by potassium uptake via the ouabain-sensitive Na+-K+-ATPase. 8. The results provide evidence for ion movements across the luminal plasma membrane of proximal tubular cells in rabbit renal cortical slices.

Some effects of monovalent anion replacement on the volume and composition of cells in incubated slices of rat renal cortex

Steady-state cellular water content and cation content and concentration have been studied in slices of rat renal cortex incubated in media in which Cl- was replaced by various monovalent anions at pH 7.35. Anions derived from low molecular weight aliphatic acids caused net uptake of cell water and K+. In the presence of larger anions cell water content fell in a manner related to anionic equivalent weight, but water content in media containing anions from weak aliphatic or alicyclic acids was slightly but consistently higher than that in media containing anions from strong acids. Cell K+ content did not decrease in these media. Aromatic anions caused enhanced cell water loss. When external pH adjusted to 6.8 or 7.8 it was found that in media containing anions from weak acids, but not from strong acids, increasing pH was associated with significantly decreased cell water content.

Effects of medium acetate on cellular volume in rabbit renal cortical slices

Slices of rabbit renal cortex were incubated at 25 degrees C in media in which acetate replaced chloride. There was gross cellular swelling in isosmotic 132 mM-acetate medium, and this swelling was unique in that, with a normal medium potassium concentration, it was accompanied by a substantial increase in cellular potassium content. This accumulation of potassium, but not the cellular swelling, was dependent upon metabolism and inhibited by ouabain. This accumulation of potassium was not dependent upon the cellular swelling. It also occurred in a hyperosmotic acetate medium in which swelling was minimized. In isosmotic media, the cellular swelling was proportional to medium acetate concentration and was also affected markedly by medium pH, being greatest at an initial medium pH of 7.1 and least at pH 7.7. The swelling was reversed and cellular composition restored when tissue was re-incubated in NaCl medium. Ouabain (10(-3)M) largely prevented this recovery in volume. The results are consistent with plasma-membrane-based theories, on the assumption that membranes are much more permeable to undissociated acetic acid than they are to the acetate ion. They are inconsistent with the expectations of an alternative hypothesis (the association--induction hypothesis) which ascribes the maintenance of cellular composition to properties of cellular proteins and cellular water rather than to those of the plasma membrane. The results do not favour the suggestion that cellular swelling itself results in irreversible cellular damage. The results are consistent with the hypothesis that the ouabain-inhibitable Na-K-ATPase plays a major role in the regulation of cellular volume. No alternative metabolically dependent volume regulating mechanism need be postulated to explain them.

Ions and water in the epithelial cells of rabbit descending colon

1. Isolated sheets of rabbit descending colon epithelial cells stripped from their underlying muscle coats were incubated in chambers at 37 degrees C with oxygenated media, and their non-inulin space water, sodium, potassium and chloride contents were subsequently determined. 2. With sodium Ringer bathing both surfaces, amiloride, 10(-4) M, decreased non-inulin space sodium content by 76 mmol/kg dry wt. Ouabain, 10(-3) M, caused loss of non-inulin space potassium which was not completely compensated for by uptake of sodium over 30 min incubation. Chloride and water, therefore, decreased. Amiloride, 10(-4) M, inhibited but did not prevent this uptake of sodium after ouabain. 3. Tissues exposed to sodium-free choline Ringer rapidly exchanged non-inulin space sodium for choline and, more slowly, lost potassium, chloride and water. The equilibration of sodium in the non-inulin space when sodium Ringer was restored to the mucosal medium alone was largely amiloride-insensitive. For restoration of non-inulin space potassium to normal levels, sodium was required in the serosal but not the mucosal medium. 4. Neither the absence of glucose nor the absence of chloride from the mucosal medium affected the non-inulin space sodium content when sodium was restored to the mucosal medium bathing sodium-depleted tissues. 5. It is argued that, whereas non-inulin space potassium and water contents are synonymous with their cellular values, only about one third of non-inulin space sodium is cellular when sodium Ringer bathes both surfaces, and the concentration of the sodium within the cellular transport pool approximated 20 mmol/kg H2O, consistent with estimates obtained from other techniques.

Cell volume regulation in goldfish intestinal mucosa

1. Ion and water content of goldfish intestinal mucosa, stripped free from muscular layers were measured under various incubation conditions. 2. Ouabain induces an increase in cation content that is electrically compensated for by chloride. The increase in solute content is accompanied by an increase in water content. 3. When extracellular chloride is partially replaced by sulphate, ouabain does induce cell shrinkage. 4. Anoxia induces a rapid increase in cell volume that is restored by oxygenation of the incubation solution. Ouabain prevents the restoration of volume. 5. It is concluded that the classical ouabain-sensitive Na/K pump participates in the maintenance of cellular volume. We suggest that the constancy in volume after ouabain poisoning as is reported for many tissues might be due to a low chloride conductance of its membranes. 6. Anisotonic media (range: 0.6-1.2 isotonicity), made by variation on mannitol concentration, induce changes in cell water content that deviates from the simplified van't Hoff equation by about 10%. No change in water content after the initial increase was found. 7. We conclude that goldfish enterocytes do not possess a mechanism for rapid volume readjustment.

Anion exchange and volume regulation during metabolic blockade of renal cortical slices

1. The development of swelling of rat and guinea-pig renal cortical slices was studied after metabolic blockade (hypoxia plus glycolytic blockade with iodo-acetic acid) and/or exposure to 'isotonic' high potassium, no sodium solution. 2. Swelling was greater after exposure to oxygenated high potassium solution than after metabolic blockade in physiologic Krebs-Henseleit solution. Swelling was reduced after metabolic blockade in high potassium solution compared to incubation in oxygenated high potassium solution. Increasing periods of transient metabolic blockade in Krebs-Henseleit solution progressively blunted swelling when slices were subsequently incubated in oxygenated high potassium solution. 3. Metabolic blockade in Krebs-Henseleit solution resulted in marked reductions in potassium and increases in sodium. Incubation in high potassium solution resulted in marked increases in potassium and similar low levels of sodium regardless of associated interventions. Metabolic blockade in both media resulted in significantly greater increases in renal cortical chloride than in monovalent cations (potassium plus sodium). Incubation in oxygenated high potassium solution was associated with similar increases in renal cortical chloride and total monovalent cations. 4. Renal cortical losses of solids and protein and increases in renal cortical inulin space were greater after metabolic blockade than after incubation under oxygenated conditions regardless of the incubation media. 5. These data support the conclusion that during metabolic blockade there is a significant replacement of larger intracellular anions by extracellular chloride. The loss of osmotically active intracellular anions limits the increase in renal cortical volume during metabolic inhibition and exposure to high potassium solution.