A novel assay of cell rubidium uptake using graphite furnace atomic absorption: Application to rats on a magnesium-deficient diet

Zhen, Yujie; Franz, Kay B.; Graves, Steven W.

doi:10.1016/j.jnutbio.2005.01.005

Cited by 6 publications

(5 citation statements)

References 18 publications

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“…EDLF activity was measured using a published functional bioassay, the inhibition of human red cell sodium pump activity. 17 This assay measures the quantity of rubidium ion (which is substituted for extracellular potassium ion) pumped into freshly obtained, normal human red blood cells by the membrane sodium pump (or Na, K-ATPase) in the absence or presence of plasma EDLF. The rubidium taken up into the cell cytosol after a 30-minute incubation of 1.0 mL (50% hematocrit) fresh red cells with 100 mL of control or specimen is quantified by graphite furnace atomic absorption spectrometer.…”

Section: Methodsmentioning

confidence: 99%

Digoxin Immune Fab Treatment for Severe Preeclampsia

et al. 2010

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We evaluated the efficacy, safety, and biological mechanisms of digoxin immune Fab (DIF) treatment of severe preeclampsia. Fifty-one severe preeclamptic patients were randomized in double-blind fashion to DIF ( N = 24) or placebo ( N = 27) for 48 hours. Primary outcomes were change in creatinine clearance (CrCl) at 24 to 48 hours and antihypertensive drug use. Serum sodium pump inhibition, a sequela of endogenous digitalis-like factors (EDLF), was also assessed. CrCl in DIF subjects was essentially unchanged from baseline versus a decrease with placebo (-3 +/- 10 and -34 +/- 10 mL/min, respectively, P = 0.02). Antihypertensive use was similar between treatments (46 and 52%, respectively, P = 0.7). Serum sodium pump inhibition was decreased with DIF compared with placebo at 24 hours after treatment initiation (least squares mean difference, 19 percentage points, P = 0.03). DIF appeared to be well tolerated. These results suggest DIF prevents a decline in renal function in severe preeclampsia by neutralizing EDLF. Sodium pump inhibition was significantly improved. Further research is warranted.

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Section: Methodsmentioning

confidence: 99%

Digoxin Immune Fab Treatment for Severe Preeclampsia

et al. 2010

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“…Rubidium belongs to the alkali metals. In biological systems Rb resembles potassium and is therefore used as a marker cation and substitute for Ka + in studies of the cellular sodium pump (Zhen et al 2005). Still, it is not known if Rb has a biological role in mammal systems, and it can be concluded that the literature on this topic is very limited.…”

Section: Rubidiummentioning

confidence: 99%

Elements in rice on the Swedish market: Part 2. Chromium, copper, iron, manganese, platinum, rubidium, selenium and zinc

Jorhem

Åstrand

Sundström

et al. 2008

Food Additives & Contaminants: Part A

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A survey of the levels of some essential and non-essential trace elements in different types of rice available on the Swedish retail market was carried out in 2001-03. The types of rice included long and short grain, brown, white, and parboiled white. The mean levels found were: chromium (Cr) = 0.008 mg kg(-1), copper (Cu) = 1.9 mg kg(-1), iron (Fe) = 4.7 mg kg(-1), manganese (Mn) = 16 mg kg(-1), platinum (Pt) < 0.0003 mg kg(-1), rubidium (Rb) = 3.3 mg kg(-1), selenium (Se) =0.1 mg kg(-1); and zinc (Zn) = 15 mg kg(-1). Inductively coupled plasma-mass spectrometry (ICP-MS) was used for the determination of Pt, Rb, and Se, after acid digestion. All other elements were determined using atomic absorption spectrometry (AAS) after dry ashing. Intake calculations were performed and it was concluded that rice may contribute considerably to the daily requirements of the essential elements Cu, Fe, Mn, Se, and Zn if rice consumption is high. The levels of some elements, e.g. Fe and Mn, were significantly higher in brown compared with white rice.

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“…This method has been described in detail [21]. The approach can be briefly summarized as follows: sodium pump (SP)-dependent Rb + uptake into red blood cells from non-pregnant, healthy controls is measured in the presence of serum from non-pregnant, healthy controls (as a negative, no inhibition control, i.e.…”

Section: Methodsmentioning

confidence: 99%

“…Note Rb + is not found in detectable levels in cells or the circulation but is an ion handled equivalently to K + , the natural substrate of the SP, allowing one to monitor uniquely the rate of the SP mediated Rb + entry as well as its specific inhibition. Using a RbCl standard of known concentration (40.4 µg/L), the relative standard deviation (RSD) within run was 1.46% and run-to-run was 2.67% [21]. The specimens were assayed in duplicate and the coefficient of variation for duplicates was 5.4%.…”

Section: Methodsmentioning

confidence: 99%

Association of cord blood digitalis-like factor and necrotizing enterocolitis

Graves

Esplin

McGee

et al. 2014

American Journal of Obstetrics and Gynecology

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Objective Endogenous digoxin-like factor (EDLF) has been linked to vasoconstriction, altered membrane transport and apoptosis. Our objective was to determine whether increased EDLF in the cord sera of preterm infants was associated with an increased incidence of necrotizing enterocolitis (NEC). Methods Cord sera from pregnant women enrolled in a randomized trial of MgSO4 for fetal neuroprotection were analyzed for EDLF using a red cell Rb+ uptake assay where inhibition of sodium pump-mediated Rb+ transport was used as a functional assay of EDLF. Specimens were assayed blinded to neonatal outcome. Cases (NEC, n=25) and controls (neonates not developing stage 2 or 3 NEC, n=24) were matched by study center and gestational age. None of the women had preeclampsia. Cases and controls were compared using the Wilcoxon test for continuous and the Fisher’s exact test for categorical variables. Conditional logistic regression analysis was used to assess the odds of case versus control by EDLF level. Results Cases and controls were not significantly different for gestational age (GA), race, maternal steroid use, premature rupture of membranes (PPROM) or MgSO4 treatment. In logistic models adjusted for treatment group, race, PPROM and GA, cord sera EDLF was significantly associated with development of NEC (p=0.023). Conclusions These data demonstrated an association between cord sera EDLF and NEC.

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A novel assay of cell rubidium uptake using graphite furnace atomic absorption: Application to rats on a magnesium-deficient diet

Cited by 6 publications

References 18 publications

Digoxin Immune Fab Treatment for Severe Preeclampsia

Digoxin Immune Fab Treatment for Severe Preeclampsia

Elements in rice on the Swedish market: Part 2. Chromium, copper, iron, manganese, platinum, rubidium, selenium and zinc

Association of cord blood digitalis-like factor and necrotizing enterocolitis

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