A family with mild hereditary xerocytosis showing high membrane cation permeability at low temperatures

1985 ◽  
Vol 69 (3) ◽  
pp. 309-319 ◽  
Author(s):  
G. W. Stewart ◽  
J. C. Ellory
Keyword(s):  
Room Temperature ◽  
Loop Diuretic ◽  
Cation Transport ◽  
Blood Film ◽  
Target Cells ◽  
Autosomal Dominant Trait ◽  
Transport Studies ◽  
Cation Permeability ◽  
Intracellular Electrolyte Concentrations ◽  
K Transport

1. Radioisotopic cation transport studies are described in a family whose erythrocytes had previously been found to show an abnormal net efflux of potassium when cooled to room temperature. This net efflux effect, which was inherited as an autosomal dominant trait, was associated with a few target cells on the blood film and a mild compensated haemolytic state. 2. Measurements of intracellular electrolyte concentrations, cell water and of Na+ and K+ transport rates across the membrane at 37°C were consistent with a diagnosis of mild hereditary xerocytosis. 3. Studies of cation transport in the temperature range 20–37°C revealed that the fluxes attributable to the Na+-K+ pump showed a temperature dependence comparable with that in normal cells, but that the ouabain plus loop-diuretic insensitive fluxes of K+, which probably represent the ‘passive diffusional leak’ to K+, were less sensitive to temperature than normal over the range 20–37°C. These findings were held to account for the net efflux effect previously reported.

scholarly journals CATION TRANSPORT IN YEAST

1956 ◽  
Vol 39 (5) ◽  
pp. 687-704 ◽  
Author(s):  
Ernest C. Foulkes
Keyword(s):  
Cell Membrane ◽  
Dissociation Constant ◽  
Concentration Gradient ◽  
Cation Transport ◽  
K Uptake ◽  
Present Evidence ◽  
Inhibitor Complex ◽  
Maximum Value ◽  
Low Concentrations ◽  
K Transport

1. The distribution of azide added to suspensions of bakers' yeast was studied under various conditions. The recovery of azide was estimated in the volume of water into which low concentrations of electrolytes can readily diffuse (anion space). Considerable azide disappeared from this anion space. 2. The incomplete recovery of azide in the anion space is due to its uptake by the cells. This uptake occurs against a concentration gradient at 0°C., and is attributed to binding of azide by cell constituents. 3. Confirmatory evidence is presented that one such constituent is the K carrier in the cell membrane. The azide inhibition of K transport is not mediated by inhibition of cytochrome oxidase in the mitochondria. 4. From the amount of combined azide and the experimentally determined dissociation constant of the K carrier-inhibitor complex, the maximum value for the concentration of this carrier is calculated as 0.1 µM/gm. yeast. 5. The addition of glucose and PO4 causes a secondary K uptake which is not azide-sensitive and is clearly distinct from the primary, azide-sensitive mechanism. 6. The existence of a separate carrier responsible for Na extrusion is reconsidered. It is concluded that present evidence does not necessitate the assumption that such a carrier is active in yeast.

scholarly journals Cytolytic activity of purified cytoplasmic granules from cytotoxic rat large granular lymphocyte tumors.

1984 ◽  
Vol 160 (1) ◽  
pp. 75-93 ◽  
Author(s):  
P A Henkart ◽  
P J Millard ◽  
C W Reynolds ◽  
M P Henkart
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Cytolytic Activity ◽  
Lymphoid Cells ◽  
Target Cells ◽  
Cytoplasmic Granules ◽  
Granule Protein ◽  
Surface Receptor ◽  
Ring Structures ◽  
Normal Rat

Purified cytoplasmic granules from cytotoxic rat large granular lymphocytes (LGL) tumors were cytolytic to erythrocytes, splenocytes, and a number of different lymphoid tumor cells. Granule concentrations of approximately 1 microgram/ml granule protein were adequate to lyse 100% of the erythrocytes, while the nucleated cells required up to 100 micrograms/ml granule protein to achieve complete lysis. Cytoplasmic granules purified from noncytotoxic lymphoid cells did not contain detectable cytolytic activity; purified granules from rat mast cells and rat liver lysosomes likewise failed to display cytolytic activity. However, granules prepared from normal rat peripheral blood LGL were cytolytic. Granule-mediated lysis of erythrocytes and nucleated cells was complete within 3 min at room temperature. The lytic activity required calcium at concentrations of 10(-4)-10(-2) M; magnesium or barium failed to replace calcium, while strontium could replace calcium at 10(-3)-10(-2) M when nucleated cells were the target. Exposure of LGL tumor granules to calcium before the addition of target cells resulted in an inactivation of granule cytolytic activity over the course of 20 min at room temperature. Granule cytolytic activity was heat and Pronase sensitive, and could be solubilized by 2 M salt. Examination of granules exposed to calcium in the electron microscope using negative staining showed that calcium treatment of granules results in the formation of ring-shaped structures previously described to be associated with LGL-mediated cytotoxicity. These results provide support for the hypothesis that the cytotoxic processes mediated by LGL are a secretory event characterized by the release of cytolytic material from the cytoplasmic granules after triggering by a surface receptor. The results further suggest that the ring structures visible in the electron microscope are associated with the lytic event.

Voltage-activated cation permeability in high-potassium but not low-potassium red blood cells

1990 ◽  
Vol 258 (6) ◽  
pp. C1169-C1172 ◽  
Author(s):  
J. A. Halperin ◽  
C. Brugnara ◽  
T. Van Ha ◽  
D. C. Tosteson
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Dielectric Breakdown ◽  
Cation Transport ◽  
Membrane Component ◽  
Transport Pathway ◽  
High Potassium ◽  
Human Red Blood Cells ◽  
Cation Permeability ◽  
Low Potassium

We have recently reported that voltage-activated fluxes of Na, K, and Ca occur in human red blood cells [J.A. Halperin, C. Brugnara, M. Tosteson, T. Van Ha, and D. C. Tosteson. Am. J. Physiol. 257 (Cell Physiol. 26): C986-C996, 1989]. The cation permeability increases progressively as the membrane potential becomes more inside positive above +20 mV. In this paper we show that this effect also occurs in high-potassium (HK), but not in low-potassium (LK), sheep and dog red blood cells. This result suggests that the voltage-activated cation transport pathway is not the result of nonspecific dielectric breakdown of the lipid bilayer but, rather, relates to some membrane component, presumably a protein, that is expressed in HK human and sheep but not in LK sheep and dog red blood cells.

scholarly journals Cation transport in Escherichia coli. IX. Regulation of K transport.

1978 ◽  
Vol 72 (3) ◽  
pp. 283-295 ◽  
Author(s):  
D B Rhoads ◽  
W Epstein
Keyword(s):  
Escherichia Coli ◽  
Steady State ◽  
Cation Transport ◽  
Transport Systems ◽  
Energy Requirements ◽  
Protonmotive Force ◽  
K Uptake ◽  
Kinetics Of ◽  
K Transport ◽  
External K

Kinetics of K exchange in the steady state and of net K uptake after osmotic upshock are reported for the four K transport systems of Escherichia coli: Kdp, TrkA, TrkD, and TrkF. Energy requirements for K exchange are reported for the Kdp and TrkA systems. For each system, kinetics of these two modes of K transport differ from those for net K uptake by K-depleted cells (Rhoads, D. B. F.B. Walters, and W. Epstein. 1976. J. Gen. Physiol. 67:325-341). The TrkA and TrkD systems are inhibited by high intracellular K, the TrkF system is stimulated by intracellular K, whereas the Kdp system is inhibited by external K when intracellular K is high. All four systems mediate net K uptake in response to osmotic upshock. Exchange by the Kdp and TrkA systems requires ATP but is not dependent on the protonmotive force. Energy requirements for the Kdp system are thus identical whether measured as net K uptake or K exchange, whereas the TrkA system differs in that it is dependent on the protonmotive force only for net K uptake. We suggest that in both the Kpd and TrkA systems formation of a phosphorylated intermediate is necessary for all K transport, although exchange transport may not consume energy. The protonmotive-force dependence of the TrkA system is interpreted as a regulatory influence, limiting this system to exchange except when the protonmotive force is high.

Transport Studies in Single-Crystal Films of Cosi2 and Nisi2

1983 ◽  
Vol 25 ◽  
Author(s):  
J. C. Hensel ◽  
R. T. Tung ◽  
J. M. Poate ◽  
F. C. Unterwald ◽  
D. C. Jacobson
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Room Temperature Resistivity ◽  
Transport Studies ◽  
Single Crystal Films ◽  
Crystal Films ◽  
The Difference ◽  
Temperature Resistivity

ABSTRACTTransport studies have been performed on thin films of CoSi 2 and NiSis2 in the temperature range 1 to 300 K. The conductivities are metallic with essentially the same temperature dependence; however, the residual resistivities are markedly different even though the two silicides are structurally similar (the room temperature resistivity of NiSi2 being at least twice that of CoSi2 of 15 μΩ cm). The difference is attributed to intrinsic defects in NiSi2. This defect has been simulated by ion bombardment of the film where it is also shown that Matthiesen's rule is obeyed over a remarkable range of bombardment doses.

Different cation transport inhibitor in malignant renal hypertension and in uraemia

1989 ◽  
Vol 76 (3) ◽  
pp. 329-333 ◽  
Author(s):  
Geza Simon
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Renal Hypertension ◽  
Cation Transport ◽  
Malignant Hypertension ◽  
Transport Inhibitor ◽  
Plasma Factor ◽  
Angiotensin Ii Antagonist ◽  
Control Plasma ◽  
K Transport

1. We investigated whether the previously reported circulating frusemide-like factor in rats with malignant renal hypertension was specific to this syndrome, or was also present in rats with chronic uraemia. 86Rb uptake (K+ transport) of monolayers of vascular smooth muscle cells was measured in the plasma of rats with malignant one-kidney, one-clip hypertension and of uraemic rats (60–70% nephrectomy). 2. Compared with control plasma, ouabain-insensitive 86Rb uptake of cells was reduced and ouabain-sensitive 86Rb uptake was unchanged in the plasma of rats with malignant hypertension. The reverse was found in the plasma of uraemic rats. 3. Inhibition of ouabain-sensitive 86Rb uptake of cells occurred in the plasma of rats with malignant hypertension when an angiotensin II antagonist was added to the reaction mixture. 4. The findings confirm the presence of a frusemide-like plasma factor in malignant hypertension and a ouabain-like plasma factor in uraemia. The presence of a ouabain-like plasma factor in malignant hypertension is camouflaged by an elevated circulating angiotensin II level, which stimulates K+ transport.

scholarly journals THE EFFECTS OF SICKLING ON ION TRANSPORT

1955 ◽  
Vol 39 (1) ◽  
pp. 31-53 ◽  
Author(s):  
D. C. Tosteson ◽  
E. Carlsen ◽  
E. T. Dunham
Keyword(s):  
Shape Change ◽  
Flux Ratio ◽  
Cation Transport ◽  
Cell Interior ◽  
Free Diffusion ◽  
Shape Transformation ◽  
Sickle Hemoglobin ◽  
K Concentration ◽  
K Transport ◽  
External K

The conversion of red cells of patients with sickle cell anemia (S-S) from biconcave disk to sickle shape by removal of oxygen was found to increase the fraction of medium trapped in cells packed by centrifugation from 0.036 (S.E. 0.003) to 0.106 (S.E. 0.004). The fraction of water in the cells (corrected for trapped medium) was not affected by this shape transformation. Cation transport, however, was changed profoundly. S-S cells incubated in N2 rather than O2 showed net K loss with acceleration of both influx and outflux. That this change in K transport was due to the process of sickling was indicated by (1) the persistence of the effect in the absence of plasma, (2) the absence of the effect in hypoxic S-S cells in which sickling was inhibited by alkali or carbon monoxide, (3) the reversal of the effect when sickling was reversed by exposure to O2, and (4) the independence of the effect from such potentially important factors as age of the cell population. The acceleration of K transport by sickling is probably mediated by modification of the cell surface rather than the cell interior since concentrated sickle hemoglobin solutions in O2 or N2 did not show selective affinity for K. In molecular terms, the effect of sickling on K transport can be explained by presuming that the shape change (1) opens pathways for the free diffusion of K, and (2) accelerates K transport by a non-diffusion carrier process. The evidence for the former mechanism included (a) dependence of K influx into sickled cells on the concentration of K in the medium, and (b) increase in the total cation content of sickled cells with increasing pH. Observations suggestive of a carrier process included (a) the failure of sickled cell K concentration to become equal to external K concentration even after 48 hours, (b) the deviation of the flux ratio from that characteristic of diffusion, and (c) the dependence of K influx on glycolysis.

Renal Na-K-ATPase: its role in tubular sodium and potassium transport

1982 ◽  
Vol 242 (3) ◽  
pp. F207-F219 ◽  
Author(s):  
A. I. Katz
Keyword(s):  
Cation Transport ◽  
Potassium Transport ◽  
Secondary Active Transport ◽  
Nephron Segments ◽  
Single Nephron ◽  
Acute Changes ◽  
K Transport ◽  
Sodium And Potassium ◽  
Slow Turnover

Na-K-ATPase, the enzymatic equivalent of the sodium:potassium pump, is found in large amounts in the kidney, and this organ has figured prominently both as a source for the purification of the enzyme and as a target for the study of its properties. Located on the basolateral aspect of tubule cells, renal Na-K-ATPase plays a key role in the active translocation of Na and K across this membrane as well as in the "secondary active" transport of a number of other solutes. The activity of renal Na-K-ATPase varies in parallel with sustained changes in Na or K transport, indicating the participation of this enzyme in the chronic adaptation of the kidney to altered Na reabsorption or K secretory load. Because of its slow turnover, however, the role of Na-K-ATPase in the modulation of acute changes in cation transport is unclear. Several hormones and vanadate influence renal Na-K-ATPase activity, and their importance as potential physiologic regulators of this enzyme is examined. Most of the information on the renal enzyme has been obtained from studies using homogenates or subcellular fractions thereof, but more recently the development of tubule microdissection and microanalytic methods has made possible the study of Na-K-ATPase in single nephron segments. This approach has opened new possibilities for evaluating the role of this enzyme in kidney function by facilitating correlation of enzyme activity with transport events in the same structure and by enabling us to focus the study of Na-K-ATPase on discrete anatomic subdivisions of the functionally heterogeneous nephron.

Insulin activates furosemide-sensitive K+ and Cl- uptake system in BC3H1 cells

1994 ◽  
Vol 267 (4) ◽  
pp. C932-C939 ◽  
Author(s):  
E. Weil-Maslansky ◽  
Y. Gutman ◽  
S. Sasson
Keyword(s):  
Transport System ◽  
Skeletal Muscles ◽  
Loop Diuretic ◽  
Uptake System ◽  
K Uptake ◽  
Factor I ◽  
Cl Transport ◽  
Igf I ◽  
K Transport ◽  
Cotransport Systems

Insulin augments the activity of Na(+)-K(+)-adenosinetriphosphatase (ATPase) in skeletal muscles. This study shows that when furosemide- and bumetanide-inhibitable 86Rb+ uptake is measured in the skeletal muscle-like BC3H1 cell line, insulin and insulin-like growth factor I (IGF-I) activate a loop diuretic-sensitive K+ and Cl- transport system but have no effect on Na(+)-K(+)-ATPase. The insulin-stimulated K+ transport system is extracellular Na+ concentration ([Na+]o) independent and extracellular Cl- concentration ([Cl-]o) dependent. Na(+)-independent K(+)-Cl- cotransport systems have been identified in other cells, but their sensitivity to insulin or growth factors has not been described. The affinities of the insulin-stimulated K+ uptake in BC3H1 cells for K+ (0.9 +/- 0.1 mM) and loop diuretics (5.9 x 10(-7) and 10(-7) M for furosemide and bumetanide, respectively) are higher than those of K(+)-Cl- cotransporters in other cells. Thus the insulin-stimulated K+ and Cl- transport system in BC3H1 seems kinetically different from K(+)-Cl- cotransporters in other cells. Insulin and IGF-I may activate a unique K(+)-Cl- cotransporter or activate a [Na+]o-independent K(+)-Cl- cotransport mode of Na(+)-K(+)-Cl- cotransporter in BC3H1 cells.

Loop diuretic and anion modification of NEM-induced K transport in human red blood cells

1990 ◽  
Vol 258 (4) ◽  
pp. C622-C629 ◽  
Author(s):  
L. R. Berkowitz
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Loop Diuretic ◽  
Sulfhydryl Group ◽  
Loop Diuretics ◽  
Human Red Blood Cells ◽  
Anion Substitution ◽  
Cellular Target ◽  
K Transport ◽  
Permeant Anion

The thioalkylating agent N-ethylmaleimide (NEM) causes ouabain-insensitive K loss from human red blood cells. This K loss is inhibited when intracellular Cl is replaced by another permeant anion or when loop diuretics are placed in the incubation medium after NEM exposure. In this report, we have tested the possibility that Cl replacement or loop diuretics not only influence the transport of K induced by NEM but also the interaction of NEM with its target sulfhydryl group. This possibility was examined by replacing intracellular Cl or exposing the cells to loop diuretics before NEM exposure, then measuring K loss in a Cl medium free of loop diuretics. We found that such pretreatment with either Cl substitution or loop diuretics stimulated, rather than inhibited, NEM-induced K loss. This enhancement was not additive in that the increase in K loss induced by anion substitution was not increased further when loop diuretics were also present. These data suggest that anion substitution and loop diuretics enhance the interaction of NEM with its cellular target but inhibit the K loss induced by NEM.

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