The effect of digoxin on 86rubidium uptake by erythrocytes from mothers and babies.

Kelly, J.P.; McMillen, RM; McDevitt, DG

doi:10.1111/j.1365-2125.1983.tb01462.x

Cited by 5 publications

(2 citation statements)

References 17 publications

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“…This time, the adults had a significantly lower value when compared to the neonates. The differences in results among Kelly et al (13) and ours, on the one hand, to Kearins et al (1 5), on the other hand, may be attributed to the different methods used. Similar to our data Kelly et al…”

Section: Resultscontrasting

confidence: 51%

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Comparison of the Digitalis Receptor in Erythrocytes from Preterm Infants and Adults

et al. 1988

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ABSTRACT. We compared adrubidium by erythrocytesThe membrane Na", K' , ATPase is considered by most auof preterm infants and adults as a measurement of their thorities to be the pharmacologic receptor for digitalis glycosides Na+, K+, ATPase enzyme system. In neonates, total uptake (7). By specifically inhibiting this enzyme, higher intracellular (0.92 2 0.13 pg/106 cells) and specific uptake (0.64 f concentrations of sodium are achieved; exchange of increased 0.076 pg/106 cells) were significantly higher than in adults amounts of sodium with more extracellular calcium results in (0.52 f 0.1 and 0.29 2 0.06 pg/106 cells, respectively; p < increased cardiac ionotrophy (8). However, the mechanism of 0.025). The percentage of specific uptake from total uptake action of digitalis in increasing cardiac inotrophy is still largely was higher in infants (73.3 2 2.3%) than in adults (57.9 f conjectural. 4.6%) ( p < 0.005). No differences were found in the affinityRb is a kaliumimetic cation that moves across cell membranes constant of 86Rb uptake between infants (4.35 f 0.48 ng/ in a fashion similar to potassium (9). Thus, by measuring Rb+ ml) and adults (4.85 2 0.48 nglml). Stratification of infants uptake, one may assess the activity of the membrane Na+, K", according to their serum K+ concentrations revealed that ATPase enzyme both in terms of binding capacity and affinity levels above 5.4 mEq/liter were associated with a higher (10). Rb, rubidiumAll were hospitalized in our neonatal ICU because of prema- RBC, red blood cellsturity, suspected sepsis, or respiratory distress syndrome. Twelve healthy adult volunteers served as a second group for the 86Rb Bmax, total specific uptake capacity uptake studies.Clinical studies. At the day of the study 1-ml heparinized blood samples were drawn from an existing intravenous indwellDespite continuous controversy over their clinical efficacy, ing catheter for 86Rb uptake studies. Electrolytes and creatinine digitalis glycosides are still one of the most commonly prescribed were determined in the serum and in 6-8 h urine collection. group of drugs (1). In infants and children, only a few controlled Creatinine clearance and fractional excretion of sodium and studies assessed the effect of digoxin in heart failure associated potassium were determined using standard methods. In each with congenital heart defects, and their results are inconclusive infant, potassium intake was calculated for the 2 days before the (2). Pharmacokinetic analysis has revealed that infants and chil-study and during the day of the study. dren need higher doses per kg of digoxin than adults to achieve 86Rb uptake studies. For the uptake assay of Rb in RBC the comparable serum concentrations due to faster clearance rates method described by Aronson et al. (1 1) was used with some (3). However, in some cases these differences are minimized by modifications. calculation of dose according to surface area.Erythrocytes were separated by centrifugation and washed The hypothesis that the immature organism is less s...

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Section: Resultscontrasting

confidence: 51%

“…Other studies in the newborn infant (13,15) did not specify maturity of potassium levels. Moreover, these authors did not correct their assay for cell numbers and/or hematocrit, but rather used a given volume of washed RBC.…”

Section: Resultsmentioning

confidence: 97%

Comparison of the Digitalis Receptor in Erythrocytes from Preterm Infants and Adults

et al. 1988

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Rubidium transport in human erythrocyte suspensions monitored by ⁸⁷rb NMR with aqueous chemical shift reagents

1989

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Dysprosium(III) triethylenetraamine-N,N,N',N",N"',N"'-hexaacetic acid (DyTTHA3-) was used as an aqueous chemical shift reagent in conjunction with high-resolution nuclear magnetic resonance (NMR) spectroscopy to monitor 87-rubidium (87Rb+) transport in human erythrocyte suspensions. NMR spectra demonstrated two resonances which were assigned to the intra- and extracellular compartments of the erythrocyte suspension. Uptake of 87Rb+ was shown to proceed via the [Na,K]-ATPase dependent pump as evidenced by the inhibition of uptake in the presence of ouabain. The steady state intra- to extracellular concentration ratio of 87Rb was 3.00 and 1.13 in the absence and presence of ouabain, respectively. The rate of uptake of 87Rb+ in the absence and presence of ouabain was found to be 1.3 and 0.5 mmol Rb+/L erythrocytes/h at 18 mM Rb+, respectively. Data are also presented which indicate that the intracellular component of 87Rb is less than 100% NMR visible.

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Digoxin Receptors in the Neonate

Kelly¹

1986

Pediatric Cardiology

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The effect of digoxin on 86rubidium uptake by erythrocytes from mothers and babies.

Cited by 5 publications

References 17 publications

Comparison of the Digitalis Receptor in Erythrocytes from Preterm Infants and Adults

Comparison of the Digitalis Receptor in Erythrocytes from Preterm Infants and Adults

Rubidium transport in human erythrocyte suspensions monitored by ⁸⁷rb NMR with aqueous chemical shift reagents

Digoxin Receptors in the Neonate

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The effect of digoxin on 86rubidium uptake by erythrocytes from mothers and babies.

Cited by 5 publications

References 17 publications

Comparison of the Digitalis Receptor in Erythrocytes from Preterm Infants and Adults

Comparison of the Digitalis Receptor in Erythrocytes from Preterm Infants and Adults

Rubidium transport in human erythrocyte suspensions monitored by 87rb NMR with aqueous chemical shift reagents

Digoxin Receptors in the Neonate

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Rubidium transport in human erythrocyte suspensions monitored by ⁸⁷rb NMR with aqueous chemical shift reagents