Red Blood Cell Potassium Research Articles

Changes in Blood Pressure, Plasma Triglyceride and Aldosterone Concentration, and Red Cell Cation Concentration in Patients With Hyperinsulinemia

Blood pressure, plasma concentration of triglyceride, aldosterone, renin activity (PRA), and atrial naturietic peptide (ANP), and red blood cell, urine, and plasma sodium and potassium concentration were determined in 24 healthy individuals divided into two groups defined as being either hyperinsulinemic or normoinsulinemic. The results demonstrated that the hyperinsulinemic group had significantly higher values for both systolic (P less than .01) and diastolic (P less than .05) blood pressure. In addition, plasma concentrations of triglyceride (P less than .02), aldosterone (P less than .05) and potassium (P less than .05) were higher in hyperinsulinemic individuals as compared to those who were normoinsulinemic. Furthermore, red cell potassium was lower (P less than .01) and red cell sodium higher (P less than .01) in the hyperinsulinemic group. Finally, the magnitude of hyperinsulinemia correlated directly with systolic (r = 0.50, P less than .01) and diastolic (r = 0.44, P less than .05) blood pressure, concentration of plasma triglyceride (r = 0.55, P less than .01) and aldosterone (r = 0.46, p less than .05), and erythrocyte sodium concentration (r = 0.57, p less than .01). In contrast, plasma insulin response was negatively correlated with erythrocyte potassium concentration (r = 0.40, P less than 0.05). These observations provide further support for the view that hyperinsulinemia, presumably secondary to resistance to insulin-stimulated glucose uptake, is associated with a cluster of variables that may play important roles in the etiology and clinical course of hypertension.

Sodium and Potassium in Red Blood Cells of Premature Infants during the First Few Days: Risk of Hyperkalaemia

Erythrocyte sodium and potassium were studied in 64 newborn infants including 21 very low birthweight infants (birthweight less than 1500 g) during the first three days after birth. Erythrocyte sodium showed a positive correlation with gestational age (r = 0.63, p less than 0.01) and birthweight (r = 0.66, p less than 0.01). Erythrocyte potassium was negatively correlated with birthweight (r = -0.33, p less than 0.05). The Na/K ratio in red blood cells showed a positive correlation with gestational age (r = 0.60, p less than 0.01) and birthweight (r = 0.65, p less than 0.01). In VLBW infants plasma potassium rose significantly (p less than 0.01) from 0-6 h to 12-30 h and decreased from 12-30 h to 30-60 h (p less than 0.05). Erythrocyte potassium decreased slightly from 0-6 h to 12-30 h, but not significantly. A new finding that "more immature infants have higher potassium and lower sodium concentration in RBC" may suggest a potential risk of hyperkalaemia in tiny infants.

Relationship between Red Blood Cell Potassium and Plasma Digitoxin Concentrations in Intoxicated Patients

After severe acute self-poisoning by cardiac glycosides, significant and persistent depletion of red blood cell K+ due to inhibition of Na+K+ ATPase is seen. Because of a delay between the time course of plasma digitalis concentrations and that of red blood cell K+ depletion, no direct relation exists between the two, and RBC K+ has hitherto not been considered useful as prognostic indicators of clinical outcome. In an effort to solve this problem, red blood cell K+ was measured by atomic absorption spectrophotometry and plasma digitoxin concentration assayed in six patients admitted to an intensive care unit after digitoxin self-poisoning. Using the effect compartment model of Sheiner, a relationship based on a sigmoid Emax model was able to relate the digitoxin concentration at the action site to red blood cell K+ depletion. Thus the duration of red blood cell K+ depletion could be predicted from two relative simple in vitro assays. Since RBC K+ is a marker of the inhibition of Na+K+ ATPase by digitoxin, this method could be of use for the management of patients self-poisoned with digitalis.

Erythrocyte concentrations and transmembrane fluxes of sodium and potassium in essential hypertension: Role of intrinsic and environmental factors

The intraerythrocyte sodium concentration is increased in the erythrocytes of Zaïrean Bantu with untreated hypertension, while the red blood cell potassium is not different from that of normotensive subjects. Compared with whites, normotensive healthy blacks have a higher intracellular concentration of sodium due to a depressed activity of the sodium-potassium pump. Normotensive healthy males with a positive familial background of hypertension display higher erythrocyte sodium and lower cotransport activity. None of the two measurements offer a clear-cut genetic marker of essential hypertension. In healthy women, the erythrocyte sodium concentration is lowered during the luteal as compared with the follicular phase of the menstrual cycle. This variability explains the difference observed between men and women. A low-sodium diet stimulates the activity of the sodium-potassium ATPase pump, which leads to a decrease in the erythrocyte sodium concentration. Both alterations reverse only slowly during sodium repletion. It is therefore suggested that an adequate matching for race, sex, stage of the menstrual cycle (in women), family history of hypertension, and the amount of sodium in the diet should be a prerequisite for valid conclusions when interpreting the erythrocyte concentration and fluxes of sodium.

Toxicokinetic-toxicodynamic models describing the relation of plasma and red blood cell potassium with plasma digitalis in acute human digitalis poisoning

Toxicity of cardiac glycosides involves the inhibition of the Na +-K + ATPase pump. As a consequence, extracellular K + concentration rises and intracellular K + concentration strongly decreases. Red blood cell (RBC) K + is a practical marker of ATPase inhibition. In a group of 15 patients intoxicated by digitoxin and lanatoside C, correlations between the calculated digitoxin ingested dose or plasma digitoxin levels and the kinetics of plasma K + and RBC K + have been assessed using kinetic-effect modelling. A correlation between the calculated ingested dose of digitoxin with RBC K + was found ( r = 0.64). A direct relation based on the linear model fitted the relation between extracellular K + and digitalis concentration. An indirect relation based on the Emax sigmoid model fitted the relation between RBC K + and digitoxin concentrations. Specific parameters were obtained from the linear model with a = 0.0196 ± 0.0272 and b = 0.455 ± 0.035. Specific parameters were derived from the Emax sigmoid model with k eo = 0.0139 ± 0.0052/hr and EC 50 = 91.95 ± 20.55 ng/ml, where k eo = first-order rate constant of the disappearance of the toxic effect and EC 50 = digitoxin concentration decreasing the RBC K + concentration by 50%. These data showed that the in vitro assays of plasma K + and RBC K + are convenient and predictive assays for evaluating the severity of human digitoxin poisoning.

Effect of dietary potassium chloride on feeder pig performance, market shrink, carcass traits and selected blood parameters.

A total of 288 commingled crossbred feeder pigs were purchased and transported 1,050 km in two trials to investigate the effect of added dietary potassium chloride in receiving and finishing diets on feeder pig shrink recovery, performance and pre-slaughter shrink. Diets containing 0, .48%, .96% or 1.44% added potassium chloride were fed for 2 wk post-arrival and again from 12 wk post- arrival until slaughter. There was no effect (P greater than .1) on gain (22.9 kg pay weight) or feed conversion or on plasma or red blood cell potassium for the 2-wk post-arrival period due to the inclusion of potassium chloride in the 2-wk receiving diet. Also, there was no effect (P greater than .1) of potassium chloride in diets from 12 wk post-arrival until slaughter on gain, feed conversion, market shrink, carcass dressing percentage and plasma or red blood cell potassium concentration at slaughter. These results suggest that corn-soybean meal-based diets contain sufficient potassium for pigs following a period of stress associated with marketing and transport.

Changes in red blood cell electrolytes and ATP in newborn shock.

Previous studies show an inability of the skeletal muscle cell and red blood cell to maintain sodium, potassium, and calcium homeostasis during hemorrhagic shock in adults. However, there is no information on the cellular effects of shock in the neonate. This study examined the effects of hemorrhagic shock on red cell membrane function in a newborn canine model. Changes in sodium, potassium, calcium, and magnesium concentrations in red blood cells and plasma were correlated with changes in intracellular and plasma ATP levels. Newborn dogs (n = 36), 10 to 14 days of age and weighing 501 to 707 g, were studied. After baseline studies (blood pressure, heart rate, temperature), electrolyte and ATP concentrations in red blood cells and plasma were measured. The dogs were then bled 40% of their estimated blood volumes. All parameters were measured after 1 h of shock. This shock model produced hypotension, bradycardia, and acidosis. The red blood cell sodium, calcium, water, and ATP content increased in shock, whereas intracellular magnesium fell. Red blood cell potassium levels, plasma sodium, and calcium concentrations were not significantly altered in shock, although plasma potassium and magnesium levels rose. Our data show that shock in the newborn disrupts cell membrane integrity. Intracellular accumulation of sodium and calcium occurred despite cellular ATP uptake, suggesting that high energy deficits are not the primary mechanism contributing to electrolyte imbalance in newborn shock.

Red blood cell sodium and potassium fluxes in psoriatic patients.

Psoriasis might be a widespread membrane disorder. Therefore, the red blood cell sodium, potassium and lithium outward fluxes (through Na-K-ATPase, Na-K-Cl co-transport, Li-Na countertransport and passive permeability), as well as the Na and K content, were studied in 31 psoriatic patients and 23 normal controls. A significant increase in intracellular potassium content, in the maximal velocity of the Na-K ATPase and of Na-K-Cl co-transport as well as in the outward passive permeability for Na were found in the psoriatic patients compared with controls. On the contrary, no differences were observed in sodium content, Li-Na countertransport and passive potassium permeability between the two groups. These results are compatible with a selective increase in inward, as well as outward, membrane permeability to sodium, which is compensated for by increased activity of the Na-K pump, and of the outward Na-K-Cl cotransport with a secondarily increased erythrocyte potassium content. They indicate that the red blood cell might be a useful model for the study of membrane transport in psoriatics.

Effects of red blood cell potassium and hypertonicity on the growth of Plasmodium falciparum in culture.

Malarial parasites reproduce asexually inside the erythrocytes of their vertebrate host. Relatively little is known about the interaction between host cell and parasite metabolism. In the present study the effect of host cell cation composition and osmotic shrinkage on in vitro growth and propagation of Plasmodium falciparum in human erythrocytes was investigated. It is shown that throughout the parasite cell cycle, infected cells lose potassium and gain sodium. Compartment analysis of infected cells revealed that host cell cytosol is poor in potassium and rich in sodium while in the parasite this relationship is reversed, indicating that the parasite is able to regulate its ionic composition independently. Parasites proceeded normally through their cell cycle in the presence of the sodium-pump inhibitor ouabain, although host cells lost up to 75-80% of their normal potassium content. Potassium-depleted erythrocytes harboring trophozoites and schizonts also display normal rates of protein synthesis as measured by isoleucine incorporation. Parasite growth was inhibited when infected cells were osmotically shrunken in hypertonic media, but this was not due to parasite dehydration. It is suggested that increased viscosity of host cell cytosol and/or hemoglobin gelation, are responsible for the effect, probably through interference with parasite feeding. The relevance of these results to understanding of the cellular mechanism involved in the inhibiton of parasite growth in deoxygenated sickle-trait erythrocytes is discussed.

Red blood cell electrolytes for monitoring digoxin therapy in adults.

Red blood cell (RBC) electrolyte concentrations were determined, with a method that can be applied easily in any clinical chemistry laboratory, in 18 patients not on digoxin therapy and 37 patients on maintenance digoxin therapy for various diagnoses. Of the digoxin-treated patients, 11 had electrocardiographic changes and other clinical evidence of digoxin toxicity. Mean RBC sodium was higher and mean RBC potassium was lower in patients on prolonged digoxin therapy than in controls, and these changes were more pronounced in patients with toxic symptoms. In the group of 11 patients with toxicity, a positive correlation was found between the ratio of RBC sodium to potassium and plasma digoxin levels (r = 0.8234, p less than 0.05). Plasma digoxin concentrations did not clearly distinguish between toxic and nontoxic patients. The RBC sodium/potassium ratio, however, identified 35 of 37 patients correctly, with two patients from the toxic and two patients from the nontoxic group giving the same results. Changes in intracellular erythrocyte electrolytes in adults appear to correlate closely with clinical signs of digoxin toxicity.

Quantitative local x-ray spectral microanalysis of single erythrocytes

Quantitative x-ray microanalysis was used to study the content of sodium, potassium, phosphorus and chlorine in single peripheral red blood cells of man. The method for sample preparation described permits its successful use under clinical and field conditions.

Zinc concentrations in plasma and erythrocytes in digitalized patients.

Determination of zinc, sodium, potassium and magnesium in plasma and red blood cells were performed in 31 controls and 63 patients treated with digitalis. In digitalized patients sodium and zinc concentrations in red blood cells were significantly increased. The intraerythrocyte magnesium and potassium levels as well as all investigated electrolytes in plasma remained within the normal range. There was a close relationship between the increase of sodium and zinc content in red blood cells, indicating alterations in transmembrane transport mechanisms induced by digitalis therapy.

Red blood cell sodium and potassium after hydrochlorothiazide

In six of seven healthy males 6 days of hydrochlorothiazide (HCT), 50 mg twice daily, without potassium supplements resulted in a rise in red blood cell (RBC) sodium concentration. Serum potassium concentration fell in all subjects. Four days after discontinuing HCT, intracellular sodium and extracellular potassium concentrations had normalized. Throughout the evaluation period the course of mean relative intracellular sodium was almost a mirror image of mean relative extracellular potassium. Thus, either the decline of serum potassium or of HCT (because of its inhibitory effect on Na-K-ATPase activity) might have diminished Na-K-ATPase-dependent active RBC sodium efflux with a resultant rise in erythrocyte sodium concentration. RBC potassium and serum sodium concentrations were not affected by short-term exposure to HCT.

Rubidium-86 uptake by red blood cells of breast cancer patients.

The red blood cell (RBC) uptake of rubidium-86 (Rb-86), a sensitive in vitro test of RBC membrane transport, was measured in 22 controls, 8 patients with benign breast lesions, and 30 stage I/II, 13 stage III/IV untreated breast cancers. Total Rb-86 transport was measured. Following ouabain block, passive transport was determined, allowing calculation of active Rb-86 uptake by difference. There was a significant decrease in total and passive uptake by RBCs from patients with breast cancer when compared to controls and those with benign lesions (total uptake 58.6 +/- 6.1% versus 63.6 +/- 3.9%, P less than 0.01; passive uptake 38.7 +/- 6.8% versus 42.7 +/- 4.6%, P less than 0.02). The Rb-86 uptake returned towards normal in successfully treated stages-II-to-IV patients. There were no correlations with the patient's age, hematocrit, or incubation hematocrit with RBC Rb-86 uptakes. Results from incubation in Krebs-Ringer solution were not consistent with a plasma blocking factor. The RBC potassium content was slightly increased in the cancer patients. This, along with decreased passive transport, eliminates the nonspecific malfunction of the Na-K-pump as an explanation, and suggests that the decreased uptake is a cancer-related phenomenon.

Response of the rat erythrocyte to ozone exposure.

Sprague-Dawley rats were exposed to high (6--8 ppm) and moderate (1.5 ppm) amounts of ozone (O3) for various time periods. Response of the rat erythrocyte to ozone was monitored with red blood cell potassium (rubidium) influx studies, with storage stress combined with ultrastructural studies and with levels of erythrocyte glutathione peroxidase and superoxide dismutase. Erythrocytes of rats exposed to O3 showed no significant changes either in their potassium influx or in their glutathione peroxidase and superoxide dismutase activities compared to controls. Erythrocyte differential counts on O3-exposed animals showed significant changes initially as well as following storage stress compared to controls. Rats exposed to 8 ppm O3 for 4 h showed a marked increase in echinocytes. These consistent transformations from discocytes to echinocytes following O3 exposure suggest latent erythrocyte damage has occurred.

Electron probe microanalysis of red blood cells. I. Methods and evaluation.

The concentrations of potassium, sodium, and iron in human and sheep red blood cells were measured with an electron probe. Cells were prepared for analysis by spraying them on pyrolytic graphite supports. The results obtained with this spray technique agreed well with values measured on similar cells that were prepared for analysis by freezing, sectioning, and freeze-drying. Higher Na concentrations and lower K concentrations were found to be associated with lower cell volumes in human and high-potassium sheep cells. In low-potassium sheep cells the reverse was found, lower Na and higher K concentrations were associated with lower cell volumes. However, the amounts of iron were found to remain relatively constant in all human cells.

The relationship between uric acid and potassium in normal subjects.

The serum uric acid concentration in normal healthy subjects has been studied in relation to sex, height, weight, lean body mass measured from total body potassium and predicted from the Hume-Weyers formula (1971), total body potassium, plasma potassium and urea, and packed cell volume. The strongest correlation was found with sex, but height, weight, total body potassium, lean body mass (measured and predicted) also correlated significantly with serum uric acid concentration. However, when the sex variable was removed, the other factors lost their significant correlation. Finally, total red blood cell and plasma volumes were predicted (Hume and Goldberg, 1964) and from these an estimate of total plasma uric acid, total plasma potassium, and total red blood cell potassium obtained. Measured total body potassium was found to correlate well with total plasma potassium and total red blood cell potassium independent of sex. Total plasma uric acid correlated well with measured total body potassium when both sexes were considered and when separated into male and female groups the males retained a significant correlation as did the female group.

Potassium transport and lipid composition in mammalinan red blood cell membranes

Potassium influxes in red cells from eight species have been found to follow an exponential relationship with membrane phosphatidylcholine and sphingomyelin content. This relationship with membrane phospholipid patterns was found to exist with both ouabain sensitive and insensitive fractions of potassium transport. When published values of chloride and phosphate permeabilities were compared with potassium permeabilities, correlations were found in seven out of nine of the species studied. On the basis of these findings it appears that potassium, phosphate, and chloride permeabilities in red blood cells of most species are related to the membrane phosphatidylcholine and sphingomyelin content; that is, membrane permeabilities increase with increasing amounts of phosphatidylcholine and decrease with increasing amounts of sphingomyelin. These results indicate that the membrane lipid is an important factor in transport processes in mammalian red blood cells.

Effect of short-term water deprivation in summer on Marwari sheep

SUMMARYEffect of 24 h and 48 h of water deprivation on glomerular filtration rate (GFR), and on blood and urine electrolyte levels in Marwari sheep of the Rajasthan desert, India, have been recorded. Body weight, urine volume, GFR and erythrocyte sodium concentration in these animals registered considerable decreases due to dehydration. Both plasma sodium and urinary potassium concentrations remained unaffected. While plasma potassium was somewhat reduced, the potassium in red blood cells increased after 48 h of water deprivation. The most remarkable response was in the concentration of urinary sodium which rose to more than double the normal level.

The effects ofLeptospiraserotypepomonain sheep of different haemoglobin types

Abstract Extract In the majority of adult sheep there are one or both of two genetically determined haemoglobin types designated Hb-A or Hb-B. The three phenotypes are A, AB or B. These haemoglobin types can be identified by differences in electrophoretic mobility (Harris and Warren, 1955 Agar, N. S., Evans, J. V. and Roberts, J. 1972. Red blood cell potassium and haemoglobin polymorphism in sheep. A review. Anim. Breeding Abs., 40: 407–435. [Google Scholar]; Evans et al., 1956 Blunt, M. H. and Evans, J. V. 1963. Changes in the concentration of potassium in the erythrocytes and in haemoglobin type in Merino sheepunder a severe anaemic stress. Nature (Lond.), 200: 1215–1216. [Crossref], [PubMed] , [Google Scholar]). A third haemoglobin type, designated Hb-C, is associated with the Hb-A gene and is produced underconditions resulting in anaemia (Blunt and Evans, 1963 Evans, J. V., King, J. W. B., Cohen, B. L., Harris, H. and Warren, F. L. 1956. Genetics of haemoglobin and blood potassium differences in sheep. Nature (Lond.), 178: 849–850. [Crossref], [PubMed] , [Google Scholar]). There is some evidence of a relationship between haemoglobin types and variations in certain physiological characteristics or productive traits (Agar et al, 1972 Harris, H. and Warren, F. L. 1955. Occurence of eleetrophoretically distinct haemoglobins in ruminants. Biochem. J., 60: xxix–xxix. [PubMed] , [Google Scholar]).