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Cation Exchange Between Cells and Plasma of Mammalian Blood

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The exchange of potassium between cells and plasma of heparinized human blood has been studied in vitro using the radioactive isotope K(42). The changes in cell and plasma specific activity are characteristic of a simple two-compartment system. The mean of seven determinations of the exchange rate at 38 degrees C. is 1.8 per cent of the cellular potassium per hour. The results indicate that at 38 degrees C. the rate is relatively insensitive to oxygenation or reduction of the hemoglobin, and to 1200 r of gamma radiation. With varying temperature the rate follows pseudo first order kinetics with a Q(10) of 2.35. Below 15 degrees C. the rate of loss of potassium exceeds the rate of uptake.

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... Furthermore, existing literature assumes that the perfusion quantity measured using 82 Rb is estimated RBF [21,24]. However, early investigations into the exchange rates of radioactive potassium and rubidium between plasma and erythrocytes showed rates of~2% per hour [25,26], implying that initially, and hence during renal uptake studies, the majority of injected 82 Rb will be almost exclusively present in plasma. We discuss and question whether flow values measured by 82 Rb clearance are actually representative of RBF or whether they should be interpreted as estimates of ERPF. ...
... Whether we measure estimated RBF or ERPF with 82 Rb depends on the distribution of the tracer between plasma and erythrocytes in whole blood. Early studies on potassium permeability of the erythrocyte membrane showed a very slow exchange of radioactive potassium and rubidium between plasma and erythrocytes amounting to 1.8-2.1% per hour and even less over 8 min of study [25,26]. Hence, most 82 Rb is present in the plasma during renal uptake studies, implying that the measured renal uptake values most likely represent estimated RPF after correction for extraction, if EF is close to unity. ...
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Background Changes in renal blood flow (RBF) may play a pathophysiological role in hypertension and kidney disease. However, RBF determination in humans has proven difficult. We aimed to confirm the feasibility of RBF estimation based on positron emission tomography/computed tomography (PET/CT) and rubidium-82 ( ⁸² Rb) using the abdominal aorta as input function in a 1-tissue compartment model. Methods Eighteen healthy subjects underwent two dynamic ⁸² Rb PET/CT scans in two different fields of view (FOV). FOV-A included the left ventricular blood pool (LVBP), the abdominal aorta (AA) and the majority of the kidneys. FOV-B included AA and the kidneys in their entirety. In FOV-A, an input function was derived from LVBP and from AA, in FOV-B from AA. One-tissue compartmental modelling was performed using tissue time activity curves generated from volumes of interest (VOI) contouring the kidneys, where the renal clearance of ⁸² Rb is represented by the K 1 kinetic parameter. Total clearance for both kidneys was calculated by multiplying the K 1 values with the volume of VOIs used for analysis. Intra-assay coefficients of variation and inter-observer variation were calculated. Results For both kidneys, K 1 values derived from AA did not differ significantly from values obtained from LVBP, neither were significant differences seen between AA in FOV-A and AA in FOV-B, nor between the right and left kidneys. For both kidneys, the intra-assay coefficients of variation were low (~ 5%) for both input functions. The measured K 1 of 2.80 ml/min/cm ³ translates to a total clearance for both kidneys of 766 ml/min/1.73 m ² . Conclusion Measurement of renal perfusion based on PET/CT and ⁸² Rb using AA as input function in a 1-tissue compartment model is feasible in a single FOV. Based on previous studies showing ⁸² Rb to be primarily present in plasma, the measured K 1 clearance values are most likely representative of effective renal plasma flow (ERPF) rather than estimated RBF values, but as the accurate calculation of total clearance/flow is very much dependent on the analysed volume, a standardised definition for the employed renal volumes is needed to allow for proper comparison with standard ERPF and RBF reference methods.
... Bruce and Stannard (16) have shown, using yeast cells, that radiation increased the rate of potassium leakage but decreases the rate of uptake of potassium. Sheppard and Martin (18) studying human red cell in vitro " found the cation exchange rate to be insensitive to 1200r of x-rays, and also to the oxygen or hemoglobin concentrations, Sheppard and Beyl (19) found a definite increase in the rate of loss of potassium from human red cells after irradiation greater than 6750r. A change in the rate of uptake of potassium was not observed for any dosage up to 54,000r, suggesting either that there may be sep arate mechanisms in the membrane for influx and efflux of potassium or that the ionic concentration gradients may be maintained internally by the cell, and independent of the external cellular membrane. ...
... It has been shown (Sheppard, Martin, and Beyl, 1951;Frazier, Sicular, and Solomon, 1954) that K transport in dog red cells is described by a single exponential process. This finding, together with our study both of the kinetics of 2 4 Na movement and of the nature of the heterogeneities present in the cells, provides a basis for further experiment on this interesting system. ...
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Unidirectional (24)Na fluxes across the dog red blood cell membrane were measured. The kinetics were incompatible with a single time constant but could be accounted for in terms of a two-series compartment cell model, with approximately 1% of cell Na in the outer compartment. Dog red blood cells are known to be inhomogeneous in their Na and K permeabilities. Theoretical analysis showed that such cellular inhomogeneity in the Na permeability coefficient might in principle account for the flux data. In order to evaluate the inhomogeneity effect, a technique based on the differential response of cells suspended in isosmolar high K buffers was devised to measure the variations in Na permeability in the cell population. A variation in the Na permeability coefficient of approximately 30% was found. This inhomogeneity is insufficient to account for the flux data.
... Mammalian erythrocytes are highly specialised cells with specialised physiology lacking mechanisms of volume control. In these cells, the physical permeability for cations is very low 80,81 . As a consequence, RBCs swell until a critical volume is reached, which corresponds to the state of maximal membrane stretching. ...
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In recent years, cell-based new therapeutic strategies have been intensively explored for tissue regeneration and targeted drug delivery. In this context, cells loaded with magnetic nanoparticles (MNPs) gain increasing interest as MNP migration can easily be followed in vivo by magnetic resonance imaging (MRI). Moreover, an external magnetic field enables the direction and concentration of cells loaded with MNPs at the desired sites for imaging, tissue repair, drug delivery or cancer therapy by hyperthermia. Several cell types have been used to test this strategy. This chapter focuses on loading blood cells with MNPs additionally providing an overview on general strategies for entrapment of drugs and nanoparticles in cells, examples of promising results and applications.
... Since potassium is concentrated in red blood cells by a nonlinear active transport mechanism, the resulting compartmental model is inherently nonlinear. However, experimental data reported in [45] show that potassium levels in both the plasma and red cells stay relatively constant over time and hence at steady state the tracer distribution is linear. Hence, we use the model in Fig. 1 with u 1 = u 2 = 0 and a 11 = a 22 = 0 to analyze this system with the total red blood cells containing an amount x 1 of potassium (the tracee) designated as the first compartment, and blood plasma, containing a quantity x 2 of potassium, as the second compartment. ...
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Nonnegative dynamical system models are derived from mass and energy balance considerations that involve dynamic states whose values are nonnegative. These models are widespread in biological, physiological, and ecological sciences and play a key role in the understanding of these processes. In this paper we develop several results on stability, dissipativity, and stability of feedback interconnections of linear and nonlinear nonnegative dynamical systems. Specifically, using linear Lyapunov functions we develop necessary and sufficient conditions for Lyapunov stability, semistability, that is, system trajectory convergence to Lyapunov stable equilibrium points, and asymptotic stability for nonnegative dynamical systems. In addition, using linear and nonlinear storage functions with linear supply rates we develop new notions of dissipativity theory for nonnegative dynamical systems. Finally, these results are used to develop general stability criteria for feedback interconnections of nonnegative dynamical systems.
... When both isotopes were present, 42K activity was calculated from the difference between initial and final counts after having corrected the latter for 59 Fe decay. The K influx was calculated according to the following formula (Sheppard and Martin, 1950): ...
Article
Young cells produced in LK sheep during rapid hematopoiesis after massive hemorrhage contain more K than the cells which are normally released into the circulation. The K content in these new cells falls to that characteristic of mature LK cells after a few days in the circulation. K transport properties in young and old cells before and after massive bleeding were studied. Young and old cells were separated by means of a density gradient centrifugation technique. Evidence showing that younger cells are found in the lower density fractions is presented. Active transport of K in the lightest fraction as measured by strophanthidin-sensitive influx was four to five times greater in red cells drawn 6 days after massive bleeding while the K leak as measured by strophanthidin-insensitive influx was only slightly larger. No change after bleeding was observed in older cells which had been present in the circulation prior to the hemorrhage. It is concluded that the high K content of young cells produced in LK sheep after bleeding is due to temporary retention of membrane K transport properties characteristic of HK cells. Thus, genetically determined modification of membrane transport properties has been shown to occur in nondividing circulating red cells.
... It is usually said that with human cells potassium influx is independent of external potassium concentration over a range from 2 to 74 mm. This belief is based on the work of Raker, Taylor, Weller & Hastings (1950), Sheppard, Martin & Beyl (1951), and Solomon (1952). The finding of Raker et al. that potassium influx drops from 1-67 to 1*33 m-mole/l. ...
Chapter
Im Jahre 1886 beobachtete Hamburger 1, daß Einbringen einiger Tropfen defibrinierten Rinderblutes in Kochsalzlösungen verschiedener Konzentration zum Austritt des Hämoglobins führt, wenn die Kochsalzkonzentration kleiner ist als 0,58%. Er stellte außerdem fest, daß mit anderen Salzen qualitativ die gleiche Erscheinung zu beobachten ist, daß aber die Grenzkonzentration für den Austritt des Hämoglobins von derjenigen des Kochsalzes verschieden ist: für KNO3 1,00, NaBr 1,02, NaJ 1,55 und KJ 1,65%. Da die Molekulargewichte der Salze 101, 103, 150 und 166 betragen, besitzen die Grenzkonzentrationen der verschiedenen Salze offenbar gleiche Molarität.
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Der Transport von Na+ aus der Zelle und von K+ in die Zelle entgegen einem Konzentrationsgradienten wird durch eine (Na+ + K+)-aktivierte ATPase katalysiert. Wie die Kationen die Zellmembran durchdringen, ist bisher ungeklärt. Beim Studium der ATP-Hydrolyse durch das Enzym fand sich eine Na+-abhängige Phosphorylierung des Enzymproteins; zusätzlich scheint sich seine Konformation zu ändern. Bei der K+-abhängigen Hydrolyse des enzymgebundenen Phosphats wird wahrscheinlich die Energie für den Transport der Kationen entgegen ihrem Konzentrationsgradienten frei. Durch Umkehr des Kationen-Konzentrationsgradienten kann das Enzym ATP aus anorganischem Phosphat und ADP synthetisieren. Das Herzglykosid Strophanthin hemmt die Na+-Pumpe spezifisch, indem es das Enzym in einer Konformation festhält.
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Red corpuscles were labelled by adding 42KC1 to a blood sample kept at 37o C for 2 hrs. When reinjecting the blood sample to the patient in the course of 1 hr, within the error of the blood volume determination which is 3 %, no change in the activity of the red corpuscles could be observed.Washed labelled red corpuscles injected into the circulation lost in the average 3.5 % of their 42K content in the course of the first hr., while the mean loss per hour in the course of 24 hours was found to be 2.1 %.
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The net negativity of the surfaces of Ehrlich ascites cells was reduced by treating them with either neuraminidase or ribonuclease. Neither enzyme treatment affected the Na+ or K+ content of the cells, before or after cooling at 4°C. Experiments with K42 revealed a reduction (9.5 to 17%) in unidirectional K+-fluxes following incubation with neuraminidase, but no change after ribonuclease-treatment. Our data suggest that surface anionic sites associated with RNA and sialic acid moieties are not of major quantitative importance in regulating either intracellular Na+ and K+ concentrations, or unidirectional transmembrane K+-flux. Our results do not enable us to determine whether ion-binding to anionic sites at the electro-kinetic surface is not an essential prerequisite to transmembrane movement, or whether it is essential, but occurs through the 40% of cell surface net negativity which is unaffected by ribonuclease- and neuraminidase-treatment.
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Chapter
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Chapter
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Coronary heart disease (CHD) is the leading cause of morbidity and mortality across the entire world, in which reversion of angina or improvement of ECG remains an unrealistic therapeutic option for most patients, suggesting that microvascular dysfunction or impaired oxygen delivery might be critical factors in CHD patients. This research article, thus presents the rationale basis, clinical and experimental, for the first therapeutic innovation addressing the role of red blood cell (RBC) H/K and O2/CO2 exchanges in CHD. It is followed by a randomized single-blind trial of Amiloride and Optimal Medical Therapy (OMT, n=35 cases) vs OMT alone (n=35 cases) in patients having angina, ST-T alteration and a defective RBC-K transport. All patients had serial clinical evaluation, Ion Transport Studies, ECGs and non-invasive aortic waveform and cardiovascular hemodynamic recordings. Statistical analysis was performed by SAS. Results: Amiloride rapidly improved RBC-K (84.5±4 vs 93.5±4 mmol/lc, p<0.001), angina (80% of cases, 1.5 ±0.3 weeks,CI:1.72 to 1.45), CCS Class (1.3 ±0.5 vs 3.1 ±0.8, p<0.001) vs patients with OMT alone CCS Class (3.2 ± 0.4 vs 3.3 ± 0.5, p =0.21). Reversion of angina was sustained through the next 6-months (87% vs 26 % in OMT, RR 2.1, odds ratio 6.31, Pearson χ2 34.6,p<0.0001 at 95% CI) and 1-year (85% vs 37% OMT).At 6-months of amiloride, ECG became normal (30% vs 0%, RR ∞ uncalculated-time, odds ratio ∞, Pearson χ2 42.4 at 95% CI, p<0.0001), improved (55% vs 29%; RR2.1, odds ratio 3.16, 95% CI, p<0.0001) or unchanged (15% vs 67% OMT). At 1-year, seven patients on amiloride (18%) exhibited evidence of electrical regeneration of the heart, not observed with placebo. In Conclusion: This therapeutical innovation of amiloride improves RBC H/K and O2/CO2 function, and reverses angina, ST-T alterations while inducing electrical regeneration of the heart, in patients receiving optimal medical treatment for angina. The article has short discussion on the relevant patents to the topic.
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In writing this chapter for “Protoplasmatologia,” I have tried to confine the material to a consideration of the problems of the red cell and its breakdown as they appear at the moment. The problems of 1955 are very different from those which presented themselves tea years ago, as will he realized by anybody who compares this chapter with my monograph. “Hemolysis and Related Phenomena.” 1948. In these ten years. the situation has changed because of six new departures: the observation of fine structure. made with the electron microscope, the realization that there are many varieties of ghosts which have properties of their own, the increasing amount of evidence that some of the simplifying hypotheses regarding the osmotic behaviour of the red cell have broken down, the observation of the hitherto negleeted fragmentation phenomena, the realization that many Iytic reactions cannot be described by the equations for simple chemical reactions. and. finally. the appreciation of the fact that the mammalian red cell has a complex metabolism and that this metabolism is concerned with processes such as active ion transport.
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1. In Analogie zum Erythrocyten wurde gezeigt, daß der Mechanismus der Gewichtszunahme der Linse spontan und unter Einwirken von Äthylurethan kolloidosmotischer Natur ist. Die Gewichtszunahme läßt sich durch Kompensation mit Saccharose verhindern, vorausgesetzt, daß dabei für einen optimalen Elektrolytgehalt des Milieus gesorgt ist. 2. Glutathion kann die durch Äthylurethan bedingte Gewichtszunahme zum Teil deutlich vermindern. — Die Bedeutung des Stoffwechsels für die physiologischen Durchlässigkeitseigenschaften der Linsenkapsel wird diskutiert.
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More than thirty years have passed since the appearance of Höber’s treatise1 on the alkali metal ions in this handbook. Since then the literature on the biological functions and effects of these ions has encreased enormously. The mere bulk of material has forced the authors to abandon the vain attempt to cover all the papers with a bearing on the field. Instead they have tried to choose from the abundance primarily what they feel can be organized into a coherent picture of the biological role of the alkali metal ions.
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Im vorliegenden Referat möchte ich anhand einer Auswahl experimenteller Untersuchungen über die Ionenpermeabilität roter Blutkörperchen einige aktuelle Probleme der Permeabilitätsforschung skizzieren. Um den Überblick über ein umfangreiches Material zu erleichtern, möchte ich zunächst dogmatisch darstellen, wie Membranstruktur und Zellstoffwechsel bei der Regulierung der Ionenverteilung zwischen Zellinnerem und Plasma zusammenwirken und erst anschließend mit der detaillierten Diskussion offener Fragen beginnen.
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Nach Leibniz bleiben die,, Maschinen der Natur, d. h. die Lebewesen, noch in ihren kleinsten Teilen ad infinitum Maschinen” (Monadologie § 64). Ebenso sicher aber hängen auch diese kleinsten Teile in den Organismen so untereinander zusammen, daß sie eine biologische Einheit, d. h. ein einheitlich funktionierendes System bilden: In den Zellen, Organen und den Lebewesen liegen immer wieder vergleichbare Gebilde mit charakteristischer Feinstruktur vor, z. T. mikromorphologisch darstellbar, z. T. nur aus der Funktionsweise erschließbar. Die Funktion kann grundsätzlich nur vom chemischen Standpunkt aus verstanden werden.
Article
Rabbit antibody + complement alters the permeability properties of mouse Krebs ascites tumor cells and erythrocytes. When antibody + C' acts on ascites tumor cells in a low protein medium, intracellular K+ is lost from the cells at a rate far greater than the normal leak rate. At the same time the cells lose amino acids and ribonucleotides and become fully permeable to the Na+ of the medium. When antibody + C' acts in a low protein medium, the cells swell extensively and lose most of their macromolecules to the medium (hemoglobin from erythrocytes, protein and RNA from the ascites tumor cells). If the antibody + C' acts in a medium containing protein in sufficient concentration to balance the colloid osmotic pressure of the cells, the swelling is prevented; no macromolecules are then lost from the cells, but the loss of K+ and entrance of Na+ are not altered, and the loss of amino acids and ribonucleotides is only slightly affected. It therefore appears that the action of antibody + C' is to produce functional "holes" in the animal cell membrane which permit the equilibration of cations and small molecules between cell and medium. This leads to an increase in the osmotic pressure of the cell and a rapid influx of water. The cell membrane and its "holes" are thereby stretched, permitting macromolecules to escape from the cell.
Chapter
Mathematical analysis is most often applied to data derived from the use of isotopes, either radioactive or rare stable, in metabolizing systems to establish the kinetics of the reactions, the uptake and volume of distribution of the isotope, or in establishing precursors in metabolic paths. For our purposes, a metabolizing system will be considered as intact living biological specimen, parts of such specimen in vitro (e. g., liver slices or homogenates, leaves) or purified enzymes derived from biological specimen used with appropriate substrates in vitro.
Article
Sodium and potassium exchange has been studied in the blood of the sheep, dog, cow, and man. The potassium exchange rate in human cells is practically unaltered by increasing the plasma potassium concentration approximately threefold. Comparing the results in different species the exchange rate for potassium shows a rough correlation with the intracellular amount of the element. Expressed in per cent of the cellular content sodium tends to exchange more rapidly than potassium. In three instances the specific activity curves deviate from the simple exponential behavior of a two compartment system. In the exchange of potassium in canine blood the deviation is caused by the presence of a rapidly exchanging fraction in the buffy coat cells. Such an effect does not account for the inhomogeneity of sodium exchange in human blood.
Article
Chemical investigation to identify the antioxidative constituents from the stems of a tree Cleyera japonica Thunb. resulted in the isolation of seven compounds: catechin (1), catechin 3-O-alpha-L-rhamnopyranoside (2), epicatechin (3), taxifolin (4), taxifolin 3-O-alpha-L-arabinopyranoside (5), taxifolin 3-O-alpha-L-rhamnopyranoside (6) and proanthocyanidin A-1 (7). These isolates were studied for their scavenging activities against DPPH radical, hydroxyl radical and superoxide anion radicals using spectrophotometry and/or electron spin resonance. All isolates 1-7 exhibited more potent DPPH radical inhibition activities than the positive control, ascorbic acid. In the hydroxyl radical scavenging test, compound 7 (SC50 301.6 mu M) showed potent activity higher than ascorbic acid (SC50 859.7 mu M). All of the compounds 1-7 exhibited comparable activities to ascorbic acid for superoxide anion radical scavenging. These results demonstrated that C. japonica stem extracts could be potentially used as antioxidative agents in food or cosmetic applications.
Article
An automated method was adapted to measure the concentration of Na and K in plasma, nonhemolyzed whole blood, and hemolyzed whole blood, and thus allow the calculation of erythrocyte electrolyte con- .centrations by a modified indirect method. The Na concentrations of nonhemolyzed whole blood and plasma were used to calculate the percent cell vol- ume (hematocrit) of a blood sample. The percent cell volume and concentrations of Na and K in nonhemolyzed whole blood were used to modify the indirect method of calculating erythrocyte Na and K concentrations in canine, porcine, and human blood samples. Significant differences were found between the two indirect methods (indirect and modified indi- rect) used to calculate erythrocyte Na and K con- centrations of human blood samples.
Article
Sodium and potassium exchange has been studied in the blood of the sheep, dog, cow, and man. The potassium exchange rate in human cells is practically unaltered by increasing the plasma potassium concentration approximately threefold. Comparing the results in different species the exchange rate for potassium shows a rough correlation with the intracellular amount of the element. Expressed in per cent of the cellular content sodium tends to exchange more rapidly than potassium. In three instances the specific activity curves deviate from the simple exponential behavior of a two compartment system. In the exchange of potassium in canine blood the deviation is caused by the presence of a rapidly exchanging fraction in the buffy coat cells. Such an effect does not account for the inhomogeneity of sodium exchange in human blood.
Article
Freshly drawn heparinized human whole blood is exposed to x-rays in amounts up to 54,000 r in vitro and then equilibrated under a controlled atmosphere at 24 or 38°C. For as long as 26 hours following exposure, potassium is progressively lost from the cells and quantitatively replaced by sodium with little, if any, osmotic disturbance. The mean rate of loss at 20,000 r and 24°C. is about 0.4 per cent of the initial cell potassium per hour and approximately doubles for a 20,000 r increase. It is accentuated if blood is stored at low temperature (5°C.) following radiation exposure. Isotope experiments show that the rate of entrance of potassium into the cells is practically unaltered, the principal effect being an acceleration of the rate from cells to plasma. This suggests that radiation may have interfered with a mechanism of selective potassium accumulation based on preferential retention of the element. The sodium which enters the cells following irradiation contributes to the rapidly exchanging portion of the cellular sodium, suggesting that this fraction is ionic sodium.
Article
Full-text available
Unlabelled: Coronary heart disease (CHD) is the leading cause of morbidity and mortality across the entire world, in which reversion of angina or improvement of ECG remains an unrealistic therapeutic option for most patients, suggesting that microvascular dysfunction or impaired oxygen delivery might be critical factors in CHD. This research article, thus presents the rationale basis, clinical and experimental, for the first therapeutic innovation addressing the role of red blood cell (RBC) H/K and O2/CO2 exchanges in CHD. It is followed by a randomized single-blind trial of Amiloride and Optimal Medical Therapy (OMT, n=35 cases) vs OMT alone (n=35 cases) in patients having angina, ST-T alteration and a defective RBC-K transport. All patients had serial clinical evaluation, Ion Transport Studies, ECGs and non-invasive aortic waveform and cardiovascular hemodynamic recordings. Statistical analysis was performed by SAS. Results: Amiloride rapidly improved RBC-K (93.5 ±4 vs 84.5 ±4 mmol/lc, p= < 0.001), angina (80% of cases, 1.5 ±0.3 weeks, CI:1.72 to 1.45), CCS Class (1.3 ±0.5 vs 3.1 ±0.8, p < 0.001) vs patients with OMT alone CCS Class (3.2 ± 0.4 vs 3.3 ± 0.5, p =0.21). Reversion of angina was sustained through the next 6-months (87% vs 26 % in OMT, RR 2.1, odds ratio 6.31, Pearson x2 34.6,p < 0.0001 at 95% CI) and 1-year (85% vs 37% OMT). At 6-months of amiloride, ECG became normal (29% vs 0%, RR ∞ uncalculated-time, odds ratio ∞, Pearson x2 42.4 at 95% CI, p < 0.0001), improved (55% vs 29%; RR2.1, odds ratio 3.16, 95% CI, p < 0.0001) or unchanged (15% vs 67% OMT). At 1-year, seven patients on amiloride (18%) exhibited evidence of electrical regeneration of the heart, not observed with placebo. In conclusion: This therapeutical innovation of amiloride improves RBC H/K and O2/CO2 function, and reverses angina, ST-T alterations while inducing electrical regeneration of the heart, in patients receiving optimal medical treatment for angina. The article has short discussion on the relevant patents to the topic.
Article
Summary Nous avons recherché les effets de diverses substances appliquées seules ou en combinaison avec une irradiation x, sur les caractères de perméabilité des hématies provenant des espèces suivantes: homme, chien, coq et pigeon. Nos résultats s'interprètent le mieux en postulant que la perturbation ionique consécutive à une irradiation x est sous la dépendence d'une inhibition de l'ATPase nécessitant du Na et du K pour son activité maximum. Parmi les substances étudiées aucune ne s'est avérée exercer d'effet radioprotecteur. Toutefois, dans le cas des hématies de chien, l'hémolyse produite par l'irradiation est moins importante en présence de cystéamine. La situation inverse est observée avec les hématies humaines puisque l'hémolyse est accrue par la présence de cystéamine. Signalons enfin que l'ion CN n'excerce aucun effet radioprotecteur, que le système biologique utilisé possède ou non la chaîne des cytochromes.
Article
An automated method was adapted to measure the concentration of Na and K in plasma, nonhemolyzed whole blood, and hemolyzed whole blood, and thus allow the calculation of erythrocyte electrolyte concentrations by a modified indirect method. The Na concentrations of nonhemolyzed whole blood and plasma were used to calculate the percent cell volume (hematocrit) of a blood sample. The percent cell volume and concentrations of Na and K in nonhemolyzed whole blood were used to modify the indirect method of calculating erythrocyte Na and K concentrations in canine, porcine, and human blood samples. Significant differences were found between the two indirect methods (indirect and modified indirect) used to calculate erythrocyte Na and K concentrations of human blood samples.
Article
Whole human blood is incubated for periods of ½ to 3 hours with K42 at 37°C. At the close of this period, called pre-incubation, the plasma is removed from the cells and the cells, now become radioactive, are again incubated in a mixture of plasma and buffer for periods of up to 10 additional hours. The time course of the K42 activity of the incubating medium is followed. Characteristically, after 2 hours of pre-incubation, the activity in the medium rises to a peak about 1 and ½ hours after resuspension, and then falls slowly until at 10 hours it is very close to its initial value at the beginning of the resuspension interval. This transient rise in K42 activity in the medium is taken to indicate that the red cell does not consist of a single uniform K compartment, but contains at least two compartments. Thus one cellular compartment contains a reservoir of high specific activity K which provides the specific activity gradient necessary to drive the K42 content of the medium to its transient peak. Experiments with Na indicate that its behavior in this respect is unlike that of K. The experimental data are matched to a simple model system which is capable of theoretical analysis with the aid of an analogue computer. The model system, whose characteristics agree fairly well with those observed experimentally on red cell suspensions, comprises two intracellular compartments, one containing 2.35 m.eq. K/liter blood, and the other 44.1 m.eq. K/liter blood. The plasma K content is 2.64 m.eq./liter blood. The flux between plasma and the smaller intracellular compartment is 0.65 m.eq. K/liter blood hour; that between the smaller and the larger intracellular compartment, 1.77 m.eq. K/liter blood hour; and that between the larger intracellular compartment and the plasma is 0.34 m.eq. K/liter blood hour.
Article
The way in which the lectins concanavalin A (Con A) and Ricinus communis agglutinin (Ricin) alter the K+ content of Ehrlich ascites tumor cells was investigated. Unidrectional and net fluxes were determined in unwashed cells during a time course following lectin addition. Total influx, ouabain sensitive influx, Mg++- and Na+-K+-ATPase activity were all unaffected. Cell ATP content was normal for at least 19 minutes after exposure to Con A. Early after contact with Ricin or Con A efflux was stimulated 2-3-fold, resulting in net K+ loss, but after 20 minutes efflux had returned to normal. Ricin and Con A acted similarly although Ricin was present at only 1/50 the concentration of Con A. When the findings are evaluated together with previous work it is suggested that a particular membrane glycoprotein may be concerned in the efflux alteration observed.
Article
The activation method of measuring slow neutron cross sections is discussed, in connection with the survey made at Argonne Laboratory. A table is given listing 131 activation cross sections of 65 elements and properties of the radio isotopes produced.
Article
The basic equation for the mixing of radioactive isotopes is dR/dt = I grad a, where dR/dt is the flux of radioactivity; a, the relative specific activity; and I, the interfusion constant. The equation is applied to systems of compartments and some electrical analogies are presented. As special cases of the unconstrained systems treated in an earlier paper two constrained systems are discussed in which only a single radioactive isotope is required for the study of transport phenomena. One of these (mammillary system) consists of a central compartment communicating with a number of peripheral compartments. In the other (catenary system) the compartments are arranged chainwise. Equations are derived for the n‐compartment mammillary system relating the time dependent specific activities of the compartments to the exchange rates between the peripheral and central compartments and to their content of substance being exchanged. In analyzing the effect of lumping of a series of compartments into a single equivalent one the case where the exchange rates cluster about a mean is discussed in some detail. In the catenary system the greater mathematical difficulties are indicated including the fact that the results depend on the order of the compartments. It is pointed out that in mammalian physiological experiments observations confined to only one compartment such as the circulating blood are insufficient for a complete analysis.
Article
Expressions are derived for a system of n compartments whereby the amount of a substance S which has moved from any one compartment to any other can be determined in a single experiment from measurements of the amounts of n tagged species in the individual compartments. It is shown that n individual species of S are required which must be uniformly mixed and behave identically but must be distinguishable by the observer. The application of the equations to studies using multiple isotopic tracers is described, and the special case of a two compartment system is analyzed in detail.
Article
By using radioactive isotopes in tissue cultures, the rate of permeation of substances into cells can be measured independently of concurrent metabolic reactions of these substances. Techniques of obtaining and analyzing data are described. Examples are given using radioactive potassium and phosphorus. Using cultures of chick embryo muscle, turnover time for cell potassium is 6 hours, and for cell inorganic phosphate is 7 hours in the examples cited. Permeability rates, based on estimates of the cell surface involved and expressed as millimoles per cm.2 per hour, are of the order of magnitude of 10–6 for potassium and of 10–7 for phosphate.
Article
The diffusion coefficients for the exchange of potassium across the membrane of erythrocytes of humans, rats, and rabbits have been determined by the use of artificially radioactive potassium, both into and out of the erythrocytes both in vitro and in vivo. The diffusion coefficients found in minutes(-1) were 0.2 to 0.25 x 10(-3) for human, 0.32 to 0.665 x 10(-3) for rabbits, and 1.0 x 10(-3) for rat erythrocytes. Rabbit erythrocytes appear to be more permeable in vivo. Reasons are advanced to explain the failure of earlier workers to demonstrate appreciable exchange of potassium in erythrocytes.
A photoelectric method for the microdeterminafion of potassium in blood plasma by the chloroplatinate precipitation
  • R M Tenery
  • C E Anderson
Tenery, R. M., and Anderson, C. E., A photoelectric method for the microdeterminafion of potassium in blood plasma by the chloroplatinate precipitation, J. Biol. Chem. 1940, 185, 659.
Radioactive Indicators; Their Application in Biochemistry, Animal Physiology, and Pathology
  • G Hevesy
Hevesy, G., Radioactive Indicators; Their Application in Biochemistry, Animal Physiology, and Pathology, New York, Interscience Publishers, Inc., 1948.
Note on the permeability of red blood corpuscles to potassium, K. Danake Vidensk
  • H Levi
Levi, H., Note on the permeability of red blood corpuscles to potassium, K. Danake Vidensk. Sdsk., Mat-fys., 1945, 23, No. 10, 1.